NASP

Here is a speaker design for novice builders.  I have called it NASP (Noob Audiophile Speaker).  It is built round the SEAS: -

29TFF/W (H1318) Fabric tweeter, price $43.9 each, and the Peerless PPB-6.5″ Polycone woofer PPB 830874.  This woofer is now renamed, so there is a discrepancy in the name on the simulations, however it is the same woofer. Price is $57.9.  The drivers are available from Madisound

This is a good beginner’s project.  The impedance is very uniform at 8 ohms and will be an easy load for ANY amp.

I designed this for an experienced builder for his brother in law to do his first project.  Results were highly favorable.

The crossover consists of a third order Butterworth low pass filter, formed by L2, L3 and C2.  The Zobel network that corrects the impedance rise, so the low pass filter can work correctly is formed by Req and Ce.  Rm, Cm and Lm can be omitted, they just flatten the impedance curve.

The high pass filter is a second order Linkwitz-Riley formed by C1 and L1.  Level matching is accomplished by the L-pad Rp1 and Rp2.

The crossover is nice and smooth.  Time and phase aberrations are minimal and very acceptable.

The box is a fourth order BB4 0.5 cu.ft. ported reflex enclosure.  The F3 is 51.5 Hz.  There is no ripple and QL is 7 so the bass will be tight without being over dry.  The box though small should be well braced.

Here are the pdf. files of the box and crossover.

nasp-bassbox-pro.pdf

nasp-crossover.pdf

Please note that this is a beginner’s project.   It should be straightforward to build.  All crossover parts can be obtained from Madisound.

The design, in order to have a very flat 8 ohm impedance curve, is not diffraction compensated.  In most rooms best results will be achieved of the speaker is not too far from room boundaries.

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