The way I view it, inverse tapered [TQWT] are for when a vented alignment requires too long a vent to get a low vent mach.
Constant tapered [TL] are for all those that fall in between the TQWT and positive tapered [horn] that are for higher Qts drivers [> ~0.4 Qts'], though sometimes used with drivers best suited for a simple TL.
Ditto for vented [mass loaded] variants: ML-TQWT, ML-TL, ML-horn [aka ML-Voigt].
Qts' = Qts + any added series resistance [Rs]: mh-audio.nl - Home
GM
Constant tapered [TL] are for all those that fall in between the TQWT and positive tapered [horn] that are for higher Qts drivers [> ~0.4 Qts'], though sometimes used with drivers best suited for a simple TL.
Ditto for vented [mass loaded] variants: ML-TQWT, ML-TL, ML-horn [aka ML-Voigt].
Qts' = Qts + any added series resistance [Rs]: mh-audio.nl - Home
GM
Ok so space permitting tapered horn is the preferred cabinet design due to better efficiency.
Tapering a TL (mouth < throat) reduces box size requirements and extends the useful passband, at the expense of some output capability and the increased possibility of vent compression effects at high output levels.
The exact opposite happens when mouth> throat.
Image: tapered offset-TL (grey) vs. straight offset-TL (red) with the same driver. Box size has increased from 114 L to 190 L going from tapered to straight.
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That is some significant increase in volume but worth it if you're chasing bottom end. Assume expanding would be in the order of 300+ liters.
when you are chasing bottom end remember to check the driver Xmax because the diaphragm displacement will increase as well, so the if you already decided wich driver to use you won't have much freedom regarding volume. If you focus on the FR so you might end with few drive options.
As a trade off, if the cab is planed to be used as HT, so you don't need too much power, in this case there is no problem to trade some Xmax to lower the response but it will limit you the mach input power or at least if you play at max power i will have more distortion.
As a trade off, if the cab is planed to be used as HT, so you don't need too much power, in this case there is no problem to trade some Xmax to lower the response but it will limit you the mach input power or at least if you play at max power i will have more distortion.
What causes you to reach to Xmax? I was told that OB speakers suffer from it, yet my OB bass drivers barely moves (TC Sounds Pro 5100) is probably due to quite heavy suspension, but does less restriction, or more restriction like in a sealed box cause the driver to react?
I do have a few drivers already for some additional music / HT speakers for a friend.
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Xmax is maximum LINEAR excursion. Distortion increases rapidly if the driver's cone starts to exceed Xmax.
Xmech the excursion point at which damage will occur. Most good drivers have suspensions that stiffen up quite a bit after the driver's cone is driven past Xmax to make it very difficult to hit Xmech.
The amount of power you have to feed a driver for the cone to reach Xmax depends on the parameters of the system that you're using it in (box size, tuning) and of course the spectrum of the signal that you're feeding it with.
With the trade-off of a longer, larger cab for a given tuning, though one can increase the TQWT to the same net volume, acoustic path-length and achieve a lower tuned gain bandwidth.
As always, it's about using whichever alignment best overall meets the needs of the app.
GM
WRT vented alignments, 'mass loading' is MJK's phrase for the vent's acoustic damping of the cab's 1/4 WL TL pipe action.
If you add a front cavity to the driver like a Karlson cab or compression horn driver has or even the rear cavity [box] of a BLH, it's an acoustic low pass filter.
GM
Sure, though don't 'bend' Hoffman at all.
Bipoles work in sealed or vented alignments, which a TL is, though don't recall any builds in recent times, but have periodically been popular in recent decades, especially in the '90s, 2000s when Sonotube and other type cardboard tubes were all the rage for 'sub' systems, though only a relative few were actually TLs.
Anyway, Dave p10's sites have a number of old bipole designs labeled as 'push-push'.
GM
Something of interest - if you put the "vent" at the wide end instead of the narrow end of a TL, the resulting resonance frequency is higher. There are some supposed advantages to putting it on the wide end if the TL is destined for full-range duty, but for subwoofer duty there is some advantage to putting it at the narrow end.
Touche' Started sketching some lines up and sure enough there's no way to "share" the t line at all. Got excited a bit seeing the ROAR with shared helmholtz resonator. That said, you got my takeaway... Nothing much new in TL since then BUT drivers have surely improved.Sure, though don't 'bend' Hoffman at all.
Bipoles work in sealed or vented alignments, which a TL is, though don't recall any builds in recent times, but have periodically been popular in recent decades, especially in the '90s, 2000s when Sonotube and other type cardboard tubes were all the rage for 'sub' systems, though only a relative few were actually TLs.
Anyway, Dave p10's sites have a number of old bipole designs labeled as 'push-push'.
GM
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