Taming resonances in the Odyssey

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spectral

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  1. Panel support pillar reinforcement: Custom-made granite pieces, 1/2 inch thick, 6lbs each, attached to the speaker with thin sorbothane sheet; shifts and absorbs audible resonances out of operating range. I used #10 1-1/4 inch self-tapping screws (impossible to find in black in any small quantity). Schematic of the drawings attached
  2. Stinger RoadKill RKX4: Common cabinet reinforcement and sound absorption material
  3. EAR Isodamp C-1002-25 isolation feet: That blue thing supporting the rear foot is aircraft-grade isolation material that I also use very successfully under my VPI with stunning results

odyssey-panel-supports.jpg

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IMG_5343-2.jpg

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Very neat Peter, nicely carried out modification. Do you hear the benefits clearly of reducing the resonance? What are the uprights made from on the Prodigy, where you have fixed the granite pillars to, i'm guessing MDF?
 
Sorry Peter, i meant Odyssey, not Prodigy, maybe Tom can edit this for me before posting so i don't look like a wally! Tom?
 
Very neat Peter, nicely carried out modification. Do you hear the benefits clearly of reducing the resonance? What are the uprights made from on the Odyssey, where you have fixed the granite pillars to, i'm guessing MDF?

Thanks. Yes MDF. Here's what I said in my system's edit on this mod:

the lack of smearing results in improved timbres, tonality and imaging. Imaging improvement was particularly interesting... I have a solo timpani CD track that was always rendered center stage, though the Revox VU meters would have it quite a bit to the left - it is now to the left, and of course much clearer.

Indeed, the strengthening has made for a superior upgrade; the bass cabinet in these speakers is really stiff, unlike the Spires/Summit et al, hence your need for those panels you have attached.

At the risk of coming across as overly pompous, all these mods plus obviously the crossover, have pushed these speakers close to the Magico Q3 performance level that I recently auditioned again with my Spectral electronics. Said otherwise, the modified Odysseys are as much a poor man's Q3s, as the Q3s are the wishful thinker's electrostatics. The Q3s have clearly superior, non-resonant cabinet, but with the above mods, I struggle to hear any sound from the panel support pillars unless I stick my ear on them, and even then, it is just a tad louder than the sound of a cartridge scraping a record as heard just inches away from one's ear in a quiet room. We are talking minutely soft sounds here...

These O's still lag behind the Q3s in a number of areas, and there is nothing I can do about it: 1) The Q3 has no mechanical noise, and the O's panels (stators) themselves resonate and thus imprint their own sound; 2) The Q3's bass is a tad faster, but I find the treble a little dark for my tastes.

I love beating the system, and I think I can call all these mods a success.

Peter
 
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Peter,

As you may be aware, I used the "Roadkill" product as part of my SL3 modes posted in the tweeks section. Also installed in my Home Theater sub woofer cabinet.

For those who don't know, this product is intended to be used for car audio installations to dampen sheet metal vibrations.

Good stuff and quite effective.

Gordon
 
Hi Gordon, yes I saw you used RoadKill too... Here are the finalized structural mods, with before and after response graphs - notice the panel smoothing. DONE.

IMG_5521-2.jpg

Before:
Odyssey-Frequency-Response-Before.jpg

After:
Odyssey-Frequency-Response-After.jpg
 

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