was planning on a voigt pipe, now not so sure.
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 28th April 2011, 09:50 AM #31 diyAudio Member   Join Date: Feb 2011 Location: Dhaka Ok Russel K and look forward to your updates. -Zia
diyAudio Member

Join Date: Jun 2003
Location: Chamblee, Ga.
Quote:
 Originally Posted by planet10 What is a reverse taper? A TL is typically tapered* (as per Baily) or straight. A reverse taper would imply a voigt pipe (please note that voigt has no h in it) dave *(in reality a taper can go either way, decreasing or increasing taper would make more sense, but only if defined from a particular end, convention is from the closed end, again makes sense only in the context of a quarter wave line)
Well, since I've used this description on a regular basis to describe a TQWT [aka TQWP/TQP/TQWTL] for as long as folks on BB lists/net forums have been interested in such alignments, I'm surprised you would ask this, especially since MJK and some others schooled in electrical and/or acoustical transmission line theory have been at odds with me about my too narrowly defining it on a number of threads, but since you asked.............

A horn is a device that expands in area with increasing length from the closed [throat] end, so a reverse taper is one that contracts with increasing length from it as defined by 'opposite or contrary in position, direction, order, or character' among others since it's a relatively general term.

I normally don't think in scientific [mathematical] terms though and these are mathematical constructs, so looked up 'inverse' and while it has some of the same definitions as 'reverse', it also has mathematical ones which more narrowly defines a TQWT, apparently making it at least a more correct way to define it.

I'm surprised none of the less math challenged folks didn't long ago point this out to me, but will use 'inverse' from now on when describing a TQWT or its mass loaded [vented] ML variants.

Hmm, the only true Voigt pipes I'm aware of are those in his original patent, so only applies to horns and constant [straight] tapered TLs.

Anyway, speaker alignments are defined using electrical equivalent circuits, making TQWT [as you note] either expanding or contracting in area from the closed end, but I have, and will continue to more narrowly define them to keep from explaining what I mean each time or require the 'gentle reader' to have to look it up.

Unfortunately, since many don't agree with me presumably because it's not the most technically correct, it will only reliably apply to my postings AFAIK, so long past time for me to add an 'abbreviations' reference that will hopefully fit in my signature.

GM
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diyAudio Member

Join Date: Jun 2003
Location: Chamblee, Ga.
Quote:
 Originally Posted by planet10 same area/length as pipe dave
The shelf vent shown will have a considerably different end correction that will tune lower than the equivalent area/length pipe, though in this design's case it probably isn't enough to matter in-room, but you can check it by recalculating it and convert it to a longer pipe of course:

GM
Attached Images
 PortCorrection.jpg (89.6 KB, 209 views)
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 28th April 2011, 04:31 PM #34 diyAudio Member     Join Date: Mar 2005 Location: UK If it's any consolation Greg (not much admittedly), I decided a long time ago that your way of defining various pipe configurations worked for me, so I've used it ever since. I suppose that means we're both pariahs.
diyAudio Member

Join Date: Apr 2011
Is the principle of operation of the voigt and the metronome and the voigt basicaly the same thing? I must say the V seems a much easier build.
Attached Images
 voigt.gif (32.6 KB, 198 views)

 28th April 2011, 06:34 PM #36 frugal-phile(tm) diyAudio Moderator     Join Date: Oct 2001 Location: Victoria, BC, NA, Sol III Blog Entries: 5 Metronome is a small variation on a mass-loaded voigt. The image you show could be a voigt or an ML-Voigt. dave __________________ community sites t-linespeakers.org, frugal-horn.com, frugal-phile.com ........ commercial site planet10-HiFi p10-hifi forum here at diyA
diyAudio Member

Join Date: Jun 2003
Location: Chamblee, Ga.
Quote:
 Originally Posted by Scottmoose I suppose that means we're both pariahs.
Pretty much!

GM
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Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.

diyAudio Member

Join Date: Apr 2011
Quote:
 Originally Posted by planet10 Metronome is a small variation on a mass-loaded voigt. The image you show could be a voigt or an ML-Voigt. dave
It is the box that was posted on the previous page, I still have to add the feet and port.... was playing around in sketchup.

 29th April 2011, 11:44 AM #39 diyAudio Member     Join Date: Sep 2009 Location: City Of Villans Blog Entries: 1 lol @ GM and Scott: they say 'tailpipe', I say 'exhaust pipe'. which is more correct? swings and roundabouts..... __________________ It still amazes me every time I get something right
diyAudio Member

Join Date: Apr 2011
You say traffic light I say robot :O

I added the ports but not the feet yet (lol, kinda don't like them - the feet).
I have to say the square port is lots more apealing, as you are not looking down its throat into the cabinet's tonsils...
Attached Images
 voigt2.gif (89.6 KB, 172 views)

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