Review of the Marantz AV 8003 tuner pre/pro

March 26th, 2010

It was time to change my Rotel 1098 for something more up to date.  The Rotel unit, now four years old, had no HDMI facilities, and of course did not contain the new loss less codecs.  Also even after to going to a lot of trouble, it was impossible to make the unit totally impervious to RF interference from SCR light dimmers.  So on deciding to add Blue Ray, as there are increasing number of opera BD disc it was time for a change.

I decided on the Marantz AV8003, because it had the corps functions I wanted, especially a Neural 6 decoder, as MPR are now broadcasting the live Friday night Minnesota Orchestra broadcasts in 5-2-5 neural six.  Also the signal to noise ratio was excellent at 105 db.

I did do some measurements on the unit.

In pure direct mode, at 1 Volt output I measured the signal to noise at 106.2 db A unweighted.  I should stress this is at the limit or beyond of my older test gear.  However I think it shows that his unit is superior in the regard.

The unit has a clipping indicator for the analog inputs.  I had to use the 6 Volt out terminals of my Quad 44 preamp and crank it to get the indicator to light!

So I measured the head room.  This is a really important aspect of audio gear, and not enough attention paid to it.  The specs for the line inputs are 400 mv for I volt out at the unbalanced outputs and 2 volts out at the balanced outputs.

It took 15 volts in the clip the line in preamp and 14 volts out from the unbalanced connector before distortion was evidentb on the scope.  This is a very superior performance.

The order of the low pass LFE crossover is not stated.  The low pass crossover is fourth order.  I did not measure the high pass crossovers since I don’t use them.  My system requires the low pass crossover to be set to 60 Hz.  At 60 Hz the LFE output is 6 db down compared to a reference signal at 30 Hz.  At 120 Hz it is 30 db down.  I have not idea why manufacturers choose to hide such vital information from the prospective user.  That is irritating to say the least.

The unit is impervious to SCR noise, and is exceptionally quiet in use.

The unit is well constructed.  I did not remove the case, so as not to void the three year warranty.  However a large toroidal power transformer is visible.  The boards are stacked in logical fashion close to the inputs and outputs.  There appears to be no crowding, and I would think service would not be a nightmare.

Installation: -

I purchased the optional rack mounting brackets, which gave me one of those “what do I do now moments,” at the start of installation.

The standard practice for 19″ rack mounted equipment is to mount from the front.  The front mounting is 19″, but the space through which the equipment goes is 17.5″.  Now the main body of the case will fit the 17.5″ width.  However the case bells out at the front because of the fascia, and the brackets bell out as well, so it will not go all the way in.  So the unit has to be mounted from the back instead of the front.  Now the mounting brackets were slightly too wide to go into my rack from the back.  I think it would have gone if the rack had been fabricated of steel.  However because if humidity/rust issues I fabricated the racks from aluminum, which requires a greater thickness of metal.  So I had to take off exactly 3/32″ from each bracket with a JET band saw in my shop.

Fortunately the inside width of the mounting brackets when mounted is 17.5″, and the inside rack spacing of my racks is precisely 17.5″.  So I was able to make a cosmetically acceptable job of the installation.  As you can see, because of the need for rear mounting the inside metal edge of the rack is exposed, which it would not be with the usual front mounting.

Here is a frontal view of the mounting.

Set up: -

I took the opportunity to fully revise the some aspects of the installation as the LFE crossover is different.  I revised the active crossovers that send the the low pass output to the upper 10″ driver in the large bass lines, to improve the diffraction compensation to the 7″ drivers in the bass mid line.  The SEAS ecal drivers are a challenge to say the least.  I modified the crossovers to better compensate for the rising response of those drivers above 200 Hz.

The unbalanced LFE output goes to the lower 10″ driver.  I added an ATI L200 buffer amp, replacing my buffer amp to send the LFE signal to the upper 10″ driver also.  This requires a mono sum buffer amp, as the diffraction signal has to be stereo and the LFE is mono.  Without buffering the diffraction compensation would be mono.  The ATI L200 was connected to the balanced LFE output of the AV 8003.

Other connections were quick and straightforward, as I can get behind my equipment in the studio mechanical chase.

Doing Audio, speaker, input and video set up was quick and straight forward.

I should add that the instruction manual is poorly written, sufficiently poor that it would give the novice a lot of difficulty.  There is a lot of “Pigeon English” in the manual which is unacceptable in a unit of this quality and price.

Functionality is good.  You can can use digital and analog inputs of the same label.   If a digital signal is resented it will use that.  If an analog one is presented it will use that.  No need to go back to the menu.  That is a nice touch.

As far as recording, only an analog input selected is presented at the analog tape out.  So you can not record from the analog outs and listen and or watch something else.  That is inconvenient.  The Rotel had this covered.

I did a vet careful manual set up, before experimenting with Audyssey.  My review of Audyssey is a separate review.

The unit is easy to use.  There is a left control knob for changing inputs.  I use this the most, as you need to be at the equipment to switch units.  It is faster than using the remote.  The right knob is for volume.  The knobs are on plastic shafts and have a little wobble.  I think this was done to stop static on the fingers transmitting to the electronics and cause failure and damage.  With the Rotel, it would lock up if you touched a knob without discharging yourself first.  This unit does not require you discharge yourself.  The rack mounting by the way securely bonds the unit to the robust studio star cluster ground plane.  The power cord is two pin with no grounding prong.

There is a pull down panel to get to the other front panel controls.  The most frequently used front panel controls are the button to select the7.1 channel analog inputs, and the selector for direct and pure direct modes.  The Direct mode, by passes everything except volume, and the pure direct in addition switches off the video circuits.

Audio modes such as Dolby Plx stereo etc are best switched from the remote.  They can be changed quickly on the fly.

I have not got into file sharing yet, but I might.  I have no difficulty sending any audio file from a file my audio workstation via its RME Fireface 800, in SPDIF digital or analog.

Performance in use: -

So far the unit has performed flawlessly.  Both sound and video are beyond reproach.  In pure direct it is literally a wire with gain.

I did not have much expectation that the FM tuner would be of high caliber.  However I was wrong.  It is a first class FM tuner.  It is every bit the equal of my quad FM 4 which I hold in high regard, as do numerous others.  The unit also comes with the iBuquity HD radio system.  This unit did not endear me to that system any more than the little Sony unit I bought to evaluate that system.  An analog FM is significantly better in all aspects except dynamic range.

The only issue I have is this.   I have found is that it decodes SACD discs incorrectly from PCM via HDMI.  The rear channels in SACD should go to the center backs.  The Marantz sends them to the surrounds, which is not what should happen at all.  So I’m glad I kept my Marantz player in the rack, as I have to still use the external analog inputs for five channel SACD.

I have reviewed this recently and find that the speaker and monitoring arrangements for SACD in the US and Europe are different.  Since all my SACDS are from Europe, I have to use the 7.1 analog inputs for SACD playback.

The unit has a power draw of 60 watts and makes significant heat.  This further reinforces my view that complex processors like this should not be in the same case as power amplifiers.

So I have to say that I would recommend this unit who has need of a pre/pro for AV.

I purchased the unit from my local dealer Hi-Fi sound of Minneapolis.  I have had good relationship with them for over a quarter century.  They gave me a discount.  I purchased the unit with mounting brackets for a little over $2300.  I could not be more pleased.

Review of ATI L200 Buffer Amp

March 26th, 2010

Review of ATI Stereo line buffer amp

Pros : Compact, Versatile, Excellent Sound, Accurate Controls
Cons : Turn off thump a problem, Low output impedance
Best Uses : Blending buffer amp, Mono summing amp, Variable gain voltage amp

The ATI L200 is a useful device.

Its main uses will be to buffer blended signals.

To place a mono signal in two independent outputs.

For use as a positive or negative gain stereo or mono voltage amplifier.

The L200 has two xlr balanced inputs and two balanced outputs.

It can provide up to 28 db of gain down to zero output.

Input impedance is 40 Kohm and output impedance 40 ohms which presented a problem that I had to solve.

The unit comes with a 24 volt DC power supply. There is a 24 volt DC output that can power another unit.  Be careful if you do, the outside of the DC plug is hot!

I used my unit as part of my triamped dual aperiodically damped transmission line monitor speakers.  These are a novel design of mine and are truly full range.

However the LFE signal which is mono needs blending with the signal from the low pass active filters which are stereo.

So I took the balanced LFE out from my Marantz AV 8003 pre/pro, to the left balanced input of the L200.  I opened the unit up and moved the link to the mono sum position.  Then I could blend the LFE output with the low pass outputs of the active crossovers from the two L200 outputs

However the low 40 ohm Zs output impedance drastically dropped the output from the low pass crossovers.  So I had to modify the unit to increase the output impedance.

One other problem, when power is cut to the unit a large spike appears at input and output.  The unit sent my Marantz into reset.  So I have left the unit permanently on.  The unit contains no on/off switch.

All in all the unit is nicely made, has excellent signal to noise in all modes except maximal gain where it is noisy.  It would be better if it did not have a huge turn off thump, and had provision for a higher impedance output when used as a combining buffer amp.

However when all is said and done this is a useful unit, but for the price could be improved.

A two way speaker using the SEAS CA18RNX and Vifa D27TG-05 drive units.

February 19th, 2010

This design is a two way.  Here is the box alignment for the woofer.

Note that the driver and port will displace 0.0408 cu.ft. in the enclosure, this will have to be added to Vb.  To get to Vt you will have to add brace volumes as well.  Mineral wool (Rockwool) should be placed on the back surface behind the driver.  50% of the internal surfaces should be covered with Polyfill.  Damping is included in Vb.

This is the crossover.  Chokes should be air core. L1L2.  The value is 1.5 mh, but this is close enough to 1.6 mh.

C1 and C2Ce.

Rp1Rp2Req.

The rise below 1 kHz is intentional to correct the diffraction loss of the cabinet.  The acoustic response is for a driver on a baffle, so when loaded the rise will continue to cut off as intended.  These Vifa tweeters have a slight rise in response at 15 kHz but there is no need to notch it.

The crossover point is at 2.8 khz and both drivers are down 21 db an octave either side of crossover.  The tweeter has an Fs of 1500 kHz and ideally the tweeter should be a little further down at that point, but I think the result will be satisfactory.  This could really only be corrected by selecting a tweeter with a lower Fs.

With the diffraction compensation these speakers have to be considered essentially five ohm.  The phase response is superior and the speakers are only 90 degrees out of phase at crossover.

When the boards are constructed the inductors should be spaced from each other as far as possible and their axes at 90 degrees to one another.

This is the port you will need, you will have to cut to length.

Loon Platform Rafts

February 17th, 2010

The Loons are in trouble in Minnesota and Wisconsin.  We are now thought to be as low as 700 nesting pairs in the two states.  The Loon is moving North to Canada.

The reasons are.

1).  The rising Eagle population that takes the chicks.

2).  Fluctuating lake levels, that leave the nests away from the water.

3).  Raccoons taking the eggs on the shore line.

4).  Boat traffic in nesting areas, especially big wakes that swamp the nest and can cause loss of eggs.  Also when the Loons get scared they can become “flusher Loons” and flush their eggs.

5).  The cold windy Springs we have had of late.  The conditions are brutal on the newly hatched chicks, that in natural nest are pitched by their mother straight into the water, never to return to the nest.

On Benedict Lake we are down to two nesting pairs.  Last year one chick was produced but did not survive.  The year before there were no chicks.

So, I was informed of this fact as my neighbors as they left for Florida in the fall.  They left giving me orders to fix it!

I was steered to the Mantrap Lake program by Ms Perry at the DNR office Brainerd, who informed me they would be of more assistance then the DNR.  Seems like another program that needs less money!

On Benedict Lake, the problems have been exacerbated by the American Army Corp of Engineers operation of the Federal Dam.  Now there is a government agency that goes around spreading harm far and wide.  That is definitely an organization that needs legislating into oblivion.  Please see the page on this blog on Red River Flooding.  The problem has occurred since the Corps lost their lawsuit filed by the State of ND over their operation of Lake Sakakawea.  The Corps can no longer empty Lake Sakakawea into the Missouri river to float barges on the Mississippi, so they are taking water from lakes like ours that drain to the Mississippi watershed.

So at Ice off the lakes are high.  Then as soon as the flood run off is gone, the Corps drop the Lake levels by opening the dams.

The loons nest the day of ice off on the shore line.  The Loons can not get around on land and have to abandon their nest.  This also causes increased predation by Raccoons.

The Eagle population has increased drastically and they love the chicks.

On Benedict Lake the Loons like to nest at the entry to the Benedict River.  Unfortunately far too many fishermen and boaters, do not obey the closed throttle rule on the river, swamping nests and scaring Loons.

So the Mantrap Lake Association has been studying the Loon and assisting breeding with a rafting program.  They have identified 19 nesting areas, and have increased the population of Loons to 19 pairs.

Loons return to the same Lake.  A lake that looses its Loons is far more lilely than ot to stay silent.

Yesterday with Don, a local Artisan we constructed the latest version of the Mantrap Raft, but modified, by allowing the canopy to hinge to allow this portly old chap to easily built the nest.  Here is a late model Mantrap Raft.

Now you have to deploy the raft the day the ice goes out.  Now for obvious reasons it usually goes off on a windy day, so boat control is a significant problem.

We will try and encourage nesting away from the river. There is a relatively sheltered area when Loons have historically nested, so we will deploy our first raft 15 ft off shore from this location.  We can only put the canopy 12″ up until we have our first successful nesting.

The rafts are deigned to accomplish the following.

Provide a stable nesting area for the nesting pair that is unlikely to be swamped.

The nesting ring prevents eggs rolling into the water.

The canopy prevents predation of chicks by Eagles.

The chicks never return to a natural nest but these rafts they do, and have been observed to use the rafts for 3 to 5 weeks following nesting.  The ramp is crucial here.  The black canopy provides shelter and heat, as the sun heats the black structure.  Chick survival is much improved.

Once the Loons accept the rafts, they expect them to be there each year, and follow their raft to safe anchor, and hop right in as the boat pulls away.

Loons have been known to fight to the death over rafts so once acceptance is achieved it is desirable to have enough rafts for the nesting pairs of the lake that use them.

It can take 3 to 4 years to get the Loons to accept the rafts.

There is some push back from Fishermen who feel deprived of these nesting areas in breeding season.  The rafts and the deployment are licensed by the County Sheriff.  When legally marked with official marker buoys fishermen can not approach the nesting area without risking severe penalties.

So we will see how this endeavor progresses this year.

This nesting program has been successful.  The raft has now been deployed for 4 years at ice out.  The first year the placement was less than ideal.  The next year the raft was deployed close to successful nesting area where one chick hatched and survived.  The next year the raft was deployed in the same place.  The loons built a natural nest that was predated right away.  No chicks resulted from that pair.

The next year 2012 the loons used the raft and two healthy chicks hatched which survived.

This year 2013 the loons again used the raft and two healthy chicks hatched which are doing well at just over 5 weeks of age.

It has surprised me how well wild animals take to a device like this.  However they seem content and safe in these rafts and do not stay head down most of the time.  They sit up surveying the scene like lord and lady of the castle.

Probe into Toyota throttle control intensifies, and now Chevy Cobalt electric power steering under scrutiny. Is new technology getting ahead of safety?

February 4th, 2010

Are we letting new electronic car control systems outpace development of  fail safe mechanisms at times of failure?

Electronic devices and systems, have, and always will be prone to both unpredictable intermittent and sudden total failure.

When electronic controls and systems are used to control vital systems in cars, such as speed, steering, braking and shifting, there is grave cause for concern.  Added to which an automobile is a harsh environment for electronics.

Toyota’s recent problems with unwanted acceleration have brought these issues into focus. Worries are intensified by the fact that Toyota almost certainly has no clue as to the real cause of these incidents, but have come up with a couple of face saving sham solutions.  More likely than not this will result in larger helpings of egg on the old visage, giving new meaning to “loss of face.”

Today I had my Toyota Camry hybrid out to the dealer to get numbers off the radio/CD/GPS unit which has developed problems.  I understand from the service department this is not infrequent.  They checked the accelerator pedal and confirmed it as a Denso and not CTS.  They checked the recent recall data and said there is a carpet recall.  I told them that the carpet is firmly fixed by stout hooks, and the pedal hung from above, and nowhere near the carpet!  The service tech agreed.  With a twinkle in his eye said, “But we will be doing something to the carpet.”  Now the word so often used by  Click and Clack fits the situation perfectly: – “BOGUS!”  It is also a total waste of everyone’s time.

Toyota’s situation is rapidly deteriorating to farce.

However the issues remain serious.  This report leaves open to question whether under some circumstances the driver can exert any control over a Toyota vehicle at all.

This report gives credence to the belief that the accelerator pedal fix is a smoke screen.

Despite Ray LaHood’s retraction the Houston Police Department have parked their Toyota Camry Hybrids, and they are not involved in the pedal recall!

Toyota now have company with accidents caused by electronic controls in vital places of GM vehicles.  The electronic power steering in the Chevy Cobalt is now under intensive government scrutiny, after failure reports, accidents and deaths.  GM have this system on all their vehicles with engines 2.4 liters or less.  Ford say they will have the system on 80 to 90% of their vehicles by 2012.

From Wikipedia, this is the rational for moving to electric steering: -

[The aim of steer-by-wire technology is to completely do away with as many mechanical components (steering shaft, column, gear reduction mechanism, etc.) as possible. Completely replacing conventional steering system with steer-by-wire holds several advantages, such as:

  • The absence of steering column simplifies the car interior design.
  • The absence of steering shaft, column and gear reduction mechanism allows much better space utilization in the engine compartment.
  • The steering mechanism can be designed and installed as a modular unit.
  • Without mechanical connection between the steering wheel and the road wheel, it is less likely that the impact of a frontal crash will force the steering wheel to intrude into the driver's survival space.
  • Steering system characteristics can easily and infinitely be adjusted to optimize the steering response and feel.

As of 2007 there are no production cars available that rely solely on steer-by-wire technology due to safety, reliability and economic concerns, but this technology has been demonstrated in numerous concept cars and the similar fly-by-wire technology is in use in both military and civilian aviation applications. Removing the mechanical steering linkage in road going vehicles would require new legislation in most countries.]

In pursuit of government mandates to stretch the gallon of gas ever further, manufacturers are forced into these complex high tech systems.  In order to keep prices down the temptation to compromise safety grows by the mandate.

So if this is the way of the future, the same rigorous testing review and oversight will have to be given to automobiles as aircraft.

In addition, it is instructive to note that in the errant Toyota vehicles no OBD fault codes have shown up, and the problem goes away at least for a period of time after re starting.  To me this indicates that like aircraft, automobiles will have to have black boxes, that record data form every sensor, every driver command and computer command.  If this technology was in Toyota vehicles now, I very much doubt any facts about these serious incidents would now be in doubt.  We would then be well on our way to the right fix.

The problem is that the cost of all this is likely to put the cost of vehicle ownership outside the reach of most.  Cost I suspect will not only be prohibitive in terms of cost but maintenance.  The cost of maintaining older high mileage vehicles will put them out of the reach of low income families.  The personal and family car is destined to become a luxury for the few.

This incredible news just in today.  Our government could not get people drunk in a brewery.  Our government seems bought and paid for through out and that’s sad.

A fix for Toyota’s problem. A hypothesis that explains the facts: a way towards solutions.

January 29th, 2010

Toyota claim that it is a sticky accelerator mechanism that is causing unwanted and unexpected acceleration in their cars.  I think this is unlikely and here is why.

I have watched all the witness accounts of this problem in Toyota vehicles on the ABC News site.  Now one of these vehicles spontaneously accelerated while going down hill with the driver’s foot off the accelerator pedal.  So a sticky accelerator does not explain what this driver experienced.

Now it is valid to ask if a retired critical care physician like myself has any business posting about a problem like this.  I would plead that physicians are trained and should posses critical analysis  skills, and quickly be able to put a hypothesis together that explains all the facts.

In addition I have worked on cars and engines since my preteen years.  I work on antique and modern engines, and I’m familiar with the components of engine controls.  In addition I have had an over riding interest in electronics, and have put big systems together and I’m familiar with some aspects of circuit design and do my own service work.

In addition my son Andrew is an electrical engineer who graduated summa cum laude from the University of Minnesota.  He has reviewed this hypothesis and finds it more plausible than statements from Toyota.  We also have a vested interest.  He owns a Toyota Camry and a RAV 4.  I own a Toyota Camry.

I have managed to find a copy of the  Toyota throttle circuit in block diagram at least

As you can see it is a servo type of motor with Hall effect control.

Now I came upon this post where a mechanic on eHow says the opening of the PVC valve opens at a bad place on Toyota engines and sticks up the throttle body.

Now if the PCV valve is putting oil deposits in the area of the Hall sensor, this could easily cause the Hall effect device to send erroneous information the the ECM and explain why this problem is so prevalent in so many Toyota models.

Now if that is the problem there are two potential steps Toyota could take to remedy the problem.  When the break light is activated, a voltage should be taken off that to a relay or preferably a MOS FET switch to interrupt the signal from pins 66 and 80 of the PCM to pins 3 and 5 on the throttle body.  Now if the PCV valve effluent is gumming up the throttle body, then the throttle body should be redesigned to have the PCV valve breath into the intake manifold like on every other engine I know of.  The reason for the latter is that if the mechanism is gummed up in the throttle body then breaking power to the throttle body servo motor would not work.

The only fly in the ointment I see here is that the throttle body air flow control looks rather nasty and over complicated from the photographs.  Instead of the usual brass butterfly rotating against spring closure, this Toyota design appears to have a geared louver type of control, and cheap plastic gears at that.  I have a suspicion it might not close with power interrupted to the throttle body servo motor, like the usual arrangement would.  If that is the case, then Toyota would have to totally redesign the throttle body to make a break override be fail safe and operate independently of ECM failure.

The problem has now been documented to occur over a nine year period and seems to involve 2005 models preferentially for some reason.  So the cost to Toyota could be enormous.  If the throttle does not close at zero voltage to the throttle body motor, then this would require a new throttle body design, a new ECM module, and modification and or replacement of the throttle body motor.  This would likely cost more than older and or high mileage vehicles are worth.

If the throttle closes at zero voltage to the servo motor then the fix could be relatively simple.

Questions journalist should be asking Toyota.

1).  How will changing the throttle mechanism prevent random acceleration going down hill when the accelerator was not depressed?

2).  Does the throttle close with no power applied to the throttle servo motor?

3).  Will you quickly provide all throttle control parts, circuit details and software for immediate peer review?  If not why not?

This is I think a very dangerous situation.  I think it is valid question to ash whether or not Toyotas should be grounded until this problem is solved.

Now my hypothesis is very unlikely to be correct in every detail, but I would bet the cause and solution is something along these lines.

Runaway Toyotas: The Real Issues Behind the Scandal.

January 27th, 2010

In modern engine management the accelerator no longer has a mechanical connection to the throttle butterfly, or injector pump slide in diesels. The reason is fuel economy.

In a standard mechanical control, the accelerator sets the air flow and fuel flow follows. With the accelerator sending a signal to the engine management control via a sending unit, the engine management is in control of fuel and air independently.

This system came to Europe first in the nineties. They had runaway cars and especially heavy goods vehicles and IEC 61508 standard came about. The testing and compliance are rigorous and the engine has to die if a problem is detected with the system and the vehicle can not be restarted.

Now in 2004 Toyota withdrew models from Europe, the Camry being first. They claimed it was due to poor sales, but on my frequent visits I saw lots of them. I’m now convinced Toyota removed the vehicles from Europe because they could not meet IEC 61508.

The dealers have been urging Toyota to bring back the Camry but they have refused.

Ford are going through this process in Europe now and this is what is involved.

I think the press have done a sloppy job on this story so far.  I now find that this issue has been suppressed since 2001!

As a Toyota Camry owner, I think Toyota have a huge problem. I think Toyota and other manufacturers should be made to show their systems can meet IEC 61508. I personally don’t think another Toyota involved in this should move off the lot until they can!

This just posted.

This is how Toyota treat their engineers.

Red River of the North: – A history of flooding and possible mitigation.

April 4th, 2009

The Red River of the North arises from the the two stem rivers, the Bois de Sioux staring at Lake Traverse and the Ottertail River arising near Alexandria Minnesota.  It forms the boundary between Minnesota and North Dakota.  It crosses the US/Canadian border, entering Manitoba at Pembina/Emerson.

The Red River of the North runs its way North to Lake Winnipeg.  It follows the lake bed of Lake Agassiz.  The only remnants of this lake, the largest of the North American Pleistocene lakes, are Lakes, Winnipeg, Manitoba and Winnipegoshi.

The Red River has a wide flat valley, which has  outer, middle and inner thirds, with progressively decreasing slopes.  So the water falls faster in the outer reaches of the valley, getting funneled into the inner third were the slope is only one foot per mile.  Added to this the River flows North into colder regions.

It is therefore not surprising that the Red River is prone to severe spring floods.

The following factors in addition to the above contribute to this problem.

The Autumn is often wet, and the winter freeze can come quickly, and freeze a lot of water in place.

It stays cold until early Spring and warm up can be rapid, and a lot of water can flow into the inner valley quickly.

Springs are often wet adding more water to a critical situation at the wrong time.

Ice jams are prone to form, especially as flows start in the south flowing into a frozen river down stream.

The fall is only 1 ft per mile so flows are slow.  The flat terrain enables the river to spread out across the valley, 60 miles being recorded south of Winnipeg in years past.  This results in severe flood potential, with damage to structures and agriculture, many miles from the river.

Geologically the Red river is a young river, shallow and without steep banks, and lots of oxbows.  The banks have a lot of unstable over banking.   It also has a huge watershed, in which the Minnesota watershed is significantly dominant over the North Dakota watershed.

The issue of agricultural drainage is often cited as a cause.  However a review of a history of Red River flooding shows that flooding was even more severe prior to cultivating the Red River Valley for agriculture.

Here is a history of main flood events in the Valley, not including this years severe flooding which is not over yet.

{Floods1700s Large flood in 1776 according to anecdotal accounts; floods in Canada, especially in 1747 and 1762, substantiated by tree-ring evidence.1826 Flood of record in Canada that destroyed settlements.1882 Large flood at Fargo, N. Dak./ Moorhead, Minn., and Grand Forks, N. Dak./East Grand Forks, Minn.1897 Largest flood on record at Fargo. 1916 Large flood in Fargo and on upstream reaches; sizeable flood in Canada.1943 Large flood in Fargo/Moorhead; in an 11-day period, the Red River rose about 23 feet; St. John’s hospital was engulfed and 270 families were forced from their homes.1950 Flood that caused most severe damage ever sustained up to this point–extended time for flooding; major disaster in Winnipeg with one-third of city evacuated.1965 Widespread flooding caused by heavy rain on frozen ground.1966 Severe flooding from United States/Canada border to Winnipeg.1969 Maximum discharge recorded on the Red River at Fargo/Moorhead and Wahpeton, N. Dak./Breckenridge, Minn., and in some areas on the Sheyenne River to this date; first flood to be diverted around Winnipeg by Red River floodway. 1975 Flood that included two peaks, in spring and summer.1979 Second largest flood after 1897 (to this date) at Grand Forks and in Canada.1989 Flood that severely damaged the cities of Wahpeton and Breckenridge.1993 Summer flood caused by a series of intense thunderstorms at various locations throughout the basin. 1997 Major flooding in United States and Canada; largest recorded flood in Grand Forks/East Grand Forks; second largest in Fargo/Moorhead and Wahpeton/Breckenridge.2001 Significant flooding caused by heavy rains on frozen ground in addition to above-average snowfall. 2002 June flooding in northwestern Minnesota, especially in Roseau, Minn., and northeastern North Dakota caused by intense rainfall.2006 Spring flooding throughout basin; most cities well prepared because of improvements made since 1997.}

But not so well prepared in 2009 it seems.

If anything agriculture has most likely slightly mitigated flooding, because of the section roads, and their culverts.  These culverts often remain frozen and hold back water on the fields.  The author believes this factor likely saved Fargo form devastation in this year’s first crest.

These devastating floods occur with a frequency that makes a mockery of current incidence ratings, with 100 or even 500 year events occurring every decade or so.

These floods occur when the temperatures in the region can be harsh, below freezing and deliver punishing snow and ice storms.  These spring flooding events inflict untold misery on the inhabitants of the Red River Valley.  It is long passed the time were this recurring disaster should be a national, and now international media spectacle, to see how much misery the population can stoically endure.

After the devastating Red River flood of 1950, in which the inhabitants of Winnipeg had to be evacuated under very difficult circumstances, the Manitoba premier Duff Roblin, was instrumental in the building of the Winnipeg Flood way.  (Duffs Ditch).  This is one of the most remarkable civil engineering projects in the history of man. (To watch an interview with Duff Roblin and Ed Kuiper, click on video 3 on the above link.)

This is the story behind Duff’s Ditch and flood mitigation projects in Manitoba.

As a result of the the devastating flood of 1997, which devastated Grand Forks and East Grand Forks,  the architect of Manitoba flood mitigation, the dutch hydrological engineer, Ed Kuiper determined that the Winnipeg flood way needed an increase in capacity of at least a third.  Manitoba embarked on the Winnpeg floodway expansion project.

This project is coming to fruition.  Its progress can be followed here.

After the flood of 1997 the author was a member of the Grand Forks mayor’s flood committee to consider mitigation.  I think it is fair to say the committee favored a Grand Forks flood way to the west.  Ed Kuiper, whose engineering has been so successful and the original civil engineers of the Winnipeg flood way, Acres International, drew up a well fleshed out, and cost estimated, a diversion channel to the west of Forks on the ND side.

However the American Army corps of engineers would not sensibly consider the plan, and pressed a rush to dikes.

This is their completed plan.

It involves two problematic ring dikes to protect East Grand Forks.  There is a combination of compacted clay dikes, flood walls, removable flood walls and diversions.

Fargo has had no significant flood mitigation projects since the 1997 flood.

In conversations the author had with Ed Kuiper after the 1997 flood he was of the opinion that if a significant fraction of the added capacity of the Winnipeg flood way was ever used protecting Winnipeg, then no diking scheme would protect the large population centers of the Red River Valley in the US, and that included, the then proposed and now completed project at Grand Forks/East Grand Forks.

He is opposed to ring dikes because, unless a population is evacuated in times of flood, people become trapped in the event of a levee failure.  He also is not in favor of high diking, on the unstable soils of the Red River Valley, only low to medium diking.

So what options are there for mitigation?

Holding back water in the outer tributaries would provide some mitigation.  The Red River Watershed Management Group have some proposed projects in this regard.

The ERC at UND through the Red River Water Management Consortium have been proposing the waffle plan.   This invoves holding back the water on fields, and releasing the water in a controlled manner with the use of sluice gates.  This plan  can be shown to take 2ft of just about any flood event, and may be under some circumstances 3.5 ft.  Whether there is enough benefit to the cost of placing, managing and controlling those sluice gates is questionable.  How to make the system relibale, in the freeze thaw cycles of the Red River Valley region would take research.

However none of the above measures, even in combination would prevent devastation in severe flooding.

That leaves the option, of levees, flood walls and diversions.

The geology of the Red River Valley makes high diking a poor option.  The experience in Winnipeg has shown that a combination of low to medium diking in combination with a flood way  provides reliable protection, with minimal stress on the communities in times of flood.  This is the split flow solution, and the author’s opinion the optimal solution for mitigating flood devastation in the Red River Valley.

Even for small communities this can be a good cost effective option.  The town of Warren Minnesota suffered frequent floods form the Snake River.  They even achieved the distinction of having three devastating floods in one year.  The late Richard P. Nelson, who was mayor of Warren, brought to fruition  a Snake River diversion at Warren.  In the floods this year, the Snake River at Warren stayed below flood stage!

The brilliant Dutch hydrological engineer, Ed Kuiper has a proven track record of succesful flood mitigation in Manitoba curbing the devastating floods on the Red and Assinboine Rivers.  He has used a combination of holding dams, diking and diversions.  He is now 87.  However time has fortunately not dulled his mind.  He is the greatest expert alive on flooding in the Red River Valley.  I know he has well founded opinions about correct mitigation of flooding in the US portion of the Red River Valley.  After this years experience in Fargo/Moorhead, a high level political delagation from North Dakaota and Minnesota should consult him without delay.  Soon it will be too late!

Fargo should move to build a split flow diversion rated to a 700 year event without delay.  Grand Forks should have a diversion channel added to the West to keep water below the Sorlie bridge in a 700 year event.

iBiquity/IBOC HD (Hybrid digital) radio system. An evaluation performed using the Sony XDR-F1 HD FM/AM Digital Tuner.

March 29th, 2009


I was invited to review the Sony XDR-F1HD by Jeff Nelson, public affairs director for Minnesota Public radio (MPR).

 

My first experience of the iBiquity/IBOC hybrid digital radio system was around two years ago, when I specked and installed a system for a musician in the Falcon Heights area of the Twin Cities.  I used the Sangean HDT-1HD.  The ancillary equipment used was a NAD integrated amp and a pair of D’Appolito Thor transmission line loudspeakers.  These are a superior high-resolution speaker.  At the time of the installation, I had with me a good friend, who also has a good ear.  We used for evaluation the classical FM MPR station 99.5 out of St. Paul.  The provided dipole antenna was used which gave adequate signal at that location.

 

Impressions of the HD quality were not good.  This was not an extended evaluation.  The Sangean unit allows switching between analog FM HD.  My friend and I double blinded each other and were easily above to distinguish the two, and it was not in favor of the HD.  It sounded weird, but time did not allow detailed analysis.  A choral selection that was played sounded particularly unpleasant.  So I was not opposed to a more formal assessment of the iBiquity/IBOC Hybrid digital system.

 

We should get one irritation out of the way right away.  I think there was intention by iBiquity to pull the wool over the eyes from the start, to make people think the HD stands for high definition.  It does not.  It stands for Hybrid Digital.

 

The iBiquity digital system is broadcast on the side band of analog FM and AM broadcast systems.  It is licensed by the FTC to be broadcast at 1% of the power of the analog signal.  In theory it is supposed to be transparent to the listener of the analog signal.  However in cars at the limits of range, the digital signal adds a spit artifact to the analog FM sound as you progress.  There is an application before the FTC to boost the digital signal to 10% of the analog signal, which would reduce the analog signal a further 9%.  The result would be that the digital signal would have a range slightly beyond the range of the analog FM signal.  Currently the digital coverage is about 30% less than the analog FM signal.  This change would reduce the range of current FM signal and substantially worsen the moving artifact at the ends of the range.

 

The FM and digital signals are combined with a proprietary combiner.  This is known to cause linearity problems at the transmitter amplifier.  Traditionally transmitter amps have been class C types.  Up grade to more costly AB transmitter amps is recommended when being fed from a combiner.  One wonders how many stations have actually done this.

 

The maximum bit rate allowed by the FTC is a streaming rate of 130 kbs.  42 kbs streaming rates are common.  96 kbs is the current max bit rate currently supported in the US,  If only one digital channel was broadcast then the system would allow a maximum streaming rate of 300 kbs and support multi channel audio.  The lossy codec used is called by iBiquity HDC.  This codec is known to be derived from the PAC Lucent codec.  iBiquity claim better performance at low bit rates for their modification, more about this later.

 

The system allows for the simulcast of the analog signals broadcast by the transmitter in HD and also additional channels not broadcast in analog.  There are also extended side bands known as HD2 HD3 etc.  However as channels are added the bandwidth is shared and bandwidth has to be shared by all programs, and must fit within the analog broadcast mask as determined by the FTC to minimize inter-station interference.

 

In a simulcast situation where the HD signal is inadequate, or becomes inadequate, HD units default to analog FM.

 

The system is very complex and this narrative has to be regarded as providing minimal information for a reader to understand the broad concept of the system.

 

Now to the Sony XDR-F1HD, which is a small compact unit measuring 7 1/8 X 2 3/8 X 6 3/8 inches.  The unit is quite heavy for its size weighing 2lb 6.8 oz.

 

The front panel has on on/off button and display window.

 

The rear panel has a 75 ohm FM antenna input, two small and awkward spring-loaded connections for the AM antenna, two stereo RCA analog output terminals and a reset button.  There is no SPDIF digital output.

 

Also provided was a crude FM dipole flexible wire antenna.  The cable was bell wire type, which was neither 75 ohm cable, nor 300 ohm balanced cable.  The termination was by a 75 ohm male antenna plug.  There is no impedance matching transformer balun.  There was a frame type AM antenna with bare wire connection to the spring-loaded connectors.


Awkwardly the top panel contains a row of buttons, from left to right, display, band, scan, HD scan, menu, tune-, tune+, enter preset- and preset+.  Fortunately all these functions are duplicated on the full function remote.

 

This unit is easy to set up and use.  It is mains AC powered.  The display can show the clock, the band, the signal strength meter, which has three bars, the station name and frequency and RBDS information if available.

 

Setting the clock, adjusting the display and setting the station presets was straightforward.  There is also a sleep timer, which seems strange for a unit not containing amplification or speakers.  This mode was not evaluated.

 

This evaluation has become not only a review of this Sony unit but a comparison between iBiquity HD1 versus analog FM, and also of streaming internet audio from MPR and the XM-Sirius satellite radio system.

 

The location was on Benedict Lake, Benedict Minnesota.  As the crow flies this is about 35 miles from the MPR Bemidji transmitter at Blackduck MN.  This broadcasts the classical service on KCRB 88.5 FM and the news service on KNBJ 91.3 FM.  Both stations simulcast an HD1 hybrid digital signal.

 

Now a word about the ancillary equipment used for the evaluation.  This evaluation was carried out at Walberswick Studios Benedict.

 

A roof Yagi Uda array was in use, directionally set to the transmitter by instrument.  The unit is by Winegard, and in addition to the active dipole contains four directors and four reflectors.

 

The signal is fed down to the garage area where there is a wide band two way splitter using good 75 ohm coax cable, the two coax cables then travel in separate conduits, to a Quad FM 3 tuner in the lower level family room and to a QUAD FM 4 tuner in the fourth level studio. 

 

The Sony HD unit was formally installed in the studio.  Another wide band two-way splitter was installed in the equipment chase, connecting via good quality coax 75 ohm cable to the Quad FM 4 and the Sony XDR-F1HD.

 

The equipment list is comprehensive.

 

The analog output of the XDR-F1HD was fed to a Quad 44 preamp.  This unit designed by the late Peter Walker OBE, has an exemplary performance.  The output of the Quad 44 was fed to the studio switch bus.  From the switch bus instant connection can be made to an analog input of a Rotel RSP 1098 preamp/processor, or an analog input of an RME Fireface 800 DAC/ADC.  The Fireface 800 was connected to a Carter audio workstation via a Firewire 800 connection.  The audio workstation was designed and built by the author to meet the exacting standards required for audio processing.  The workstation is loaded with Steinberg WaveLab 6 software, and also the drivers and software to control the RME Fireface 800.  Dual screens were used.  The RME was connected to a SPDIF digital input on the Rotel RSP 1098 with a good quality (Blue Jeans) 75 ohm RCA SPDIF cable.

 

To evaluate Internet digital streaming the 128 kbs stream from MPR was used.  The player was Winamp connected to the RME unit, outputting via RCA SPDIF.

 

To compare the analog FM signal the Quad FM 4 was used.  This is a Peter Walker design form the eighties, but this high quality unit can still be considered a reference FM tuner.  This tuner was connected via analog DIN/RCA cables to an analog input of the Rotel RSP 1088.  The analog outputs from the tape outs of the Rotel unit were connected to the studio switch bus via analog RCA cables, for quick switching comparison, signal leveling and analysis in WaveLab.  In this way precisely level matched signals could be instantly switched between analog FM, HD radio and streaming Internet audio, playing the same program.  Levels were set using the very accurate metering in WaveLab and with an spl. meter.

 

A word about the speaker system is in order at this point.  This is a 7.1 channel system.  The front left and right speakers are dual aperiodically damped transmission line speakers.  The drivers in each speaker are two 7” and two 10” magnesium alloy drivers from the SEAS Excel line.  The tweeters are SEAS Excel Millennium tweeters.  There is one passive crossover and two active crossovers.  The speakers are critically damped providing non-resonant bass with a Qt of 0.5.  The speakers are powered by Peter Walker’s current dumping amplifiers, one Quad 909 and two Quad 405 2 power amps.  The system is fully step response/diffraction compensated.  In addition to a very smooth on and off axis response, the bass is highly defined and articulate.  Since high spls. can be obtained in room to 20 Hz no dedicated subwoofer is required.

 

The center speaker is another aperiodically damped transmission line using SEAS coaxial drivers, although only the lower unit has the tweeter in use.  One passive and one active crossover are used.  The speaker is diffraction compensated and powered by a Quad 909 amplifier.  This speaker is highly musical and reproduces the human voice, both sung and spoken in a remarkably realistic fashion.

 

The surround speakers are of a sealed design using two Dynaudio W 75 extended range mid-woofers, and a Dynaudio D28 AF tweeter, in a 2.5 way diffraction compensated design using passive crossovers.  The speakers are powered by a Quad 405 2 amplifier.

 

The rear back speakers are dual aperiodically damped transmission lines.  The bass drivers in each speaker are two KEF B139 units.  There is one Dynaudio M 75, D 52 AF and D21 AF per speaker.  There is one active and one passive crossover in each speaker.  The speakers are powered by two Quad 405 2 amplifiers.

 

The speaker system was designed and built by the author.  This system is considered an accurate reference monitor system built to the most exacting studio specifications, and considered amply adequate for this review.

 

The total power available to the speaker system is 2 KW continuous.

 

The electronics were powered via APC smart UPS units, including the subject of the review.

 

During the evaluation two channel stereo was largely used using the front left and right dual line speakers.  Connections were either analog stereo or two channel PCM.

 

For reasons that will be discussed in the review, Dolby PL IIx music mode was also used during part of the evaluation.

 

I should state that the Quad FM 4 receives a signal from the roof Yagi Uda array adequate for high fidelity reproduction, free of audible background hiss at the listening position, and free of any radio born, or other interference.

 

So how did the Sony XDR-F1HD perform?

 

After setting the unit up it was first used with the provided FM antenna.  Results were very disappointing.  No FM stations of listenable quality could be received.  There was not sufficient sensitivity of the tuner to activate the HD signal and it defaulted to FM.  To put this in perspective, none of our current vehicles, or any we have owned, have had trouble finding a stable FM signal at this location or immediate environs. 

 

So the tuner was plugged in to the feed from the roof Yagi Uda array trained on MPR Bemidji.  Right away things were considerably better.  It detected  both MPR stations without difficulty and the HD symbol stayed illuminated, showing the receiver was detecting and reproducing the HD signal.  The level meter has three vertical bars and all were displayed.  There were no other HD signals in the area other than from MPR.  The unit does not allow switching between analog FM and HD, so the quality could not be directly compared using only this unit.  There were over compressed rock stations that did not allow useful evaluation.  There was one country and western music station that seemed to have good clear signal, and the Sony unit provided analog FM of good quality from that station.  This was enough to convince me that the analog circuits of this unit were not a significant limiting factor.

 

One further comment about the FM sensitivity of this unit.  In order to provide analog FM of listenable quality, at least two bars on the signal meter have to be displayed.  However all three bars had to be displayed to guarantee good FM reception.  On some stations with two bars displayed reception was adequate for others it was not.  Also if reception was not adequate, in addition to poor signal to noise there was excess distortion and unpleasant modulation of the program by the noise floor.  This unit has to be judged to have poor FM sensitivity.  There are not enough FM stations close enough together on the dial to comment on FM discrimination and rejection.  However poor sensitivity is usually accompanied by poor performance in these other areas.

 

It would seem to me that though this unit is inexpensive, I paid $84.49 for my unit, including shipping; there will be significant added expense.  Unless the location is close to a transmitter, I fear a high gain roof antenna will be mandatory, especially to reliably receive HD signals.  The cost of the antenna will run around $100 and installation depending on the circumstance of the home, probably between $300 and $400 dollars, unless the owner can safely carry out the installation of the antenna.

 

The AM section was then assessed.  As is typical of modern AM tuners, the performance was dreadful.  Only a handful of AM stations could be obtained at this location were speech was even intelligible.  I could find no AM stations supporting HD, so the performance of HD AM could not be assessed.

 

One other issue:  The unit under test produced a significant amount of heat, so it needs good ventilation.  The unit becomes quite warm, but not uncomfortably so.  The power consumption is not stated but is obviously significantly higher than an analog FM tuner.  This should annoy the “greens.”  In contrast my Quad FM 4 produces no discernable heat to the touch.

 

The next part of the evaluation consisted of comparing the HD signal to analog FM from the Quad 44 and 128 kbs mp3 streaming from MPR.  For the vast majority of the testing the classical KCRB and classical streaming signal were used.

 

The first step was to carefully level match the three sources by metering within WaveLab and with an spl. meter set to slow ballistics.  Great care was taken to precisely level match.  During the time of this study I have had no assistance to blind it, however the sources are easily distinguishable, especially HD from analog FM.  There is time delay from the Internet stream, which hindered precise comparison somewhat.

 

So how did HD stack up to analog FM?  I’m sorry to have to report not well.

 

The first thing that distinguished the HD signal was a peculiar excessive ambiance that seemed to somehow unnaturally widen the sound stage.  At the same time it did not support a stable central image.  All the time one was aware of two distinct speaker sources not working well together.  Vocals, solo instruments sound wide, with no defined location in space.  This was a most disconcerting effect.  Choral selections in ambient spaces sounded particularly weird.

 

The other issue was not only a lack of bass compared to analog, but a significant reduction in the quality of the bass.  The bass stings lacked the natural bloom this speaker system so beautifully reproduces.  On this system, the notes of the individual tympani can be easily distinguished.  I could not do this from the HD signal.  The strings lacked their lovely smooth sheen and sounded significantly steely.  Piano lacked the correct timber in the bass strings and the higher strings showed some brittleness.  The brass, especially the trombones lacked their deep-throated luster.  Voices sung and spoken were also changed in timber and poorly focused.  Prolonged listening resulted in a lot of listener fatigue.  The analog FM signal was free of these defects.  These latter aspects I have noticed with all low bit rate lossy codecs.  

 

Now I would have thought that the HD would have had a clear advantage in signal to noise and therefore dynamic range.  As far as I could tell the dynamic range of the analog and HD signals was identical.  Both systems provided hiss free listening at the seated position.  When putting an ear to the tweeter the HD had a slight but not significant advantage.

 

However it was the peculiar unnatural ambiance with poor focus and the inability of the system to provide a locked central image that really caught my attention.  I compared the 360-degree phase scope patterns of the HD and analog signals in WaveLab.  The patterns were markedly different.

 

I performed an intensive Internet search to see what I could discover about this observation.  One of iBiquity’s claims is that their HDC codec performs better than other low bit rate codecs and loftily claim good performance with bit rates as low as 42 kbs.

 

I found reports that there are linear phase problems with the PAC Lucent codec.  However I eventually ran into information stating that the stereo image for the iBiquity HDC codec is M-S derived.  Now this is a technique used mostly for a type of microphone set up.  In fact this is a technique, I frequently used myself when making recordings for the public radio station KFJM in Grand Forks ND.

 

Now in this system an omni directional or forward facing directional microphone is connected to the mix desk and panned center (mono).  Then microphones are placed facing direct left or right, or a figure of 8 microphone used where the left and right facing elements are 180 degrees out of phase.  The left and right signals are then mixed with the center signal to produce the left and right channels.  Now balancing the center and side signals is crucial.  Too much center and you have a collapse of the stereo image that is close to mono.  Too much side and you have an ill focused ambient sound stage.  I would only ever use this technique when I could balance with good monitor speakers to get a believable and natural sound stage.  I would never do this balance with headphones.

 

So it seemed to me this system had too much left right and not enough center information.  The question was why?

 

Well I soon came across a paper showing that adding ambiance was the easiest way of hiding the undesirable effects of low bit rate codecs!

 

So how to put my hypothesis to the test.  I reasoned that the Dolby PLIIx music algorithm would unscramble the egg so to speak.  So I switched from two channel to Dolby PLIIx music.  Sure enough as I advanced the power slightly to the center speaker, I had a stable stereo central image and the artificial abnormal ambiance disappeared.  The problem was the sound was dull and flat and sounded like any other low bit rate codec I have ever evaluated!  So there you have the dishonest slight of hand uncovered.  The unfortunate thing is that this excess ambiance is something the inexperienced listener might glum onto and actually prefer at first hearing.  However it is not realistic or pleasing, and I’m certain would be a fundamental detriment to serious listening, especially choral music in ambient spaces.

 

So how did the mp3 128 kbs streaming stack up to analog FM?  Actually it stacked up surprisingly well!  The biggest difference was in the depth of bass and its quality. Violins were less silky and piano a little brittle.  The sung voice also was harder edged.  Of course choral music in ambient spaces, especially British boy sopranos, against powerful organs in their fine cathedrals produced a sound significantly below satisfactory.  No lossy codec I have evaluated has been up to the task of this type of program material.  For the most part this source provided comfortable listening for extended periods.  On much program it was very hard to distinguish it from analog FM.  It was far superior to the iBiquity/IBOC in performance.

 

In the course of my intensive evaluations spanning four days, I included the XM-Sirius satellite system.  In this location, my only option to receive a high definition television signal is via satellite.  I’m a subscriber to the Direct TV system.  The package includes access to the XM-Sirius satellite radio system.  So I tuned into the classical channel “Symphony Hall”.  All I can say about this was that it was an excruciatingly awful experience.

 

The sound had no dynamic range worth talking about.  The upper bass was severely bloated, the highs were rolled off, I suspect to disguise frank digital twinking artifact, which I could detect through the fog.  Like the iBiquity HD, the sound was way over ambient.  The Sirius system uses the PAC Lucent codec.  I cannot be certain of the streaming rate, but I have good reason to believe it is 64 kbs and sounds like it.  I have a hard time believing that all that investment in technology can go towards producing something so dreadful!

 

So the question becomes, what is the place of the Sony XDR-F1HD?  It is cheap enough and seems well made for the price.  However if there is an HD signal it defaults to that.  The HD quality is significantly inferior to analog FM, yet the unit cannot be switched to analog FM when receiving an HD signal.  The unit’s only use would be to receive a non-simulcast program.  At this location there is no such program available, and so the unit for me has no utility, other than to evaluate the iBiquity/IBOC hybrid digital transmission system. 

 

I should make clear that the major flaw of this unit cannot be laid at Sony’s door but iBiquity’s.  In fact I would single out iBiquity for severe criticism.  They have deliberately misled the public by giving it the acronym “HD”.  They have made claims that its performance is close or even CD quality.  MPR continue to make the claim that it is CD quality.  It is not even in striking distance of CD quality.  What it is, is a low fidelity transmission system and in no way even a serious replacement for analog FM.

 

It is another bad example of the modern decent to the bottom.  The whole scheme is to cut and reduce corners as much as possible, and fill the airwaves with more signals of poor quality.  And then deliberately mislead the public into thinking that this is a great technological advance that will bring them CD quality over the air.  A total disgrace typical of what we have seen in these recent money grubbing years.

 

 

As far as I can tell the only HD tuners are this one and those from Sangean.  The quality of the iBiquity/IBOC system is not likely to encourage higher end manufacturers to produce units of the build quality of my Quad FM 4.

 

To summarize the state of play of the systems evaluated, analog FM provides the best and most believable listening experience of the formats tested.  However the mp3 128 kbs Internet streaming ran it a surprisingly close second.  If the bit rate could be increased to 300 kbs, then this system could likely equal or probably exceed analog FM on most program material.  This would encourage the production and marketing of more Internet streaming radios.

 

The iBiquity/IBOC system falls well short of the mark in terms of required audio quality, at least for classical program.

 

The quality provided by the XM-Sirius satellite system, does not even merit consideration as a serious broadcast/listening system and the less said about it the better.

 

There is need for a much better digital replacement for analog FM.  It is now over 60 years since Major Armstrong’s first FM broadcast in New York City in 1948.  The fact that modern technology has not yet bested his broadcast system is a tribute to his achievement, which is still standing the test of time, against very inferior competition; how sad.

 

Vifa_TC14WG-49-08_optimum box

February 13th, 2009

In my view this box gives the best compromise between f3 and linearity of response.  I consider this the optimal box.