GPA 604 in Voight Pipe?? (help GM)

[atilsley]

Greg

I understand you prepared a drawing for the 604 in a voight pipe...?

If so, can I get a higher-res pic? I can't read some of the measurements.

Also, any comments/feedback from others on this design appreciated.

What sound deadening do you suggest?

I was just about to start a build on a 9.5 cubic foot unit in 25mm MDF, with a 50mm front baffle, and sturdy internal bracing.

Bottom line - will the VP give a richer/deeper/improved sound over a conventional box, similar to Stonehenge V?

Thanks.

Andrew.

[GM]

No, I spec'd one for Jay Fisher who turned it into some drawings, so please contact him for these since I'm not sure I have the most detailed available. For sure, I don't have the one for the elaborate driver mounting that was used on a MLTL design.

I've always used Altec's damping suggestion of one side, back and parallel wall opposite the vent (usually the top) with 1" acoustic fiberglass insulation (AKA duct board these days) as a first approximation.

That said, pipe horn resonances are somewhat different to a typical cab, especially if they terminate in a point, so most of the damping will be concentrated only down to ~mid way or a bit below the driver, whichever is lower. Any additional damping would normally be stuffing in the peak.

What it does is increase loading on the vent, ergo increases its acoustic efficiency which normally equates into a larger, better damped vent with improved transient/impulse response. Perceived smoothness should be on a par with an optimized maximally flat sealed alignment.

Maybe Brad will chime in with his impressions of my low tuned inverse tapered ML-Voigts which will be similar to Jay's positive tapered one WRT smoothness, transient/impulse response.

GM

[bfish]

...Maybe Brad will chime in with his impressions of my low tuned inverse tapered ML-Voigts which will be similar to Jay's positive tapered one WRT smoothness, transient/impulse response.

GM

Adjectives... hmmm...

WRT smoothness, recall the last time you heard a standup fretless bass in the right hands.

Impulse response comparison is easy if you've ever been unexpectedly slapped.

Like I assume most members experience, my exposure to 515s was limited to stock VOTTs in venues. For the first ~2-1/2 octaves, GMs 515s could never be mistaken for the low end of any stock VOTT., and while they look like bass reflex, they lack the boom at any frequency. Think EQ'd sealed, only efficient.

[valhallax]

whoa! that sounds fast tight and smooth! dual 515's per side? got pics?

[GM]

Impulse response comparison is easy if you've ever been unexpectedly slapped.

Good one! I'll have to remember it.

Thanks for your thoughts, you didn't have much of anything to say about them when you were here, so kind of figured you were underwhelmed by their decidedly un-Altec 'West Coast Sound' presentation.

GM

[atilsley]

OK, thanks guys.

I also see another 604 thread going...another Ozzie!