Re: Upgrading Subs – New Driver or new Sub –What would you do?
Stuart,
The answer is yes, a well designed dual 15" front loaded sub with two drivers running at 1000 Watts will be slightly louder than a single 15" sub with a driver of double the excursion using 4000 watts. The down side is double the cabinet size, which requires a larger truck, and more warehouse space, and set up help.
Although patents can avoid a direct copy for commercial use, as a DIY you are welcome to make TH.
Other than patents, the reason more are not using TH are several.
Rider acceptance is one, X many dual 18" cabinets may be specified. It is very difficult to convince someone that one TH (with a single 15mm Xmax 18"driver) could match four "old school" dual 18" that use drivers with less than half the excursion.
That said, putting a pair of high excursion 18" in a small BR cabinet will outperform a TH in the same size by a small margin, though using double the power and drivers.
For those with big budgets, and limited space, BR are still viable, and those selling drivers and amplifiers make more profit with BR.
Then there is the issue of alignment, a TH needs the tops delayed to properly align, while a BR will generally be within 1/4 wavelength at the crossover point and no delay maybe needed.
Few seem to understand this, and come away after hearing a poorly aligned horn system thinking that the horn sounds bad, when it was a set up problem.
Then there is the actual design, as Ivan mentioned, small details in TH design can make rather large differences, while a ported box with adequate sized ports is an easy deal.
Using Hornresp or Akabak one can design a good TH (or BR, or FLH, or FLH/BR, etc. etc.) but getting the actual physical unit to match when each fold makes a difference is difficult.
At any rate, there are a number of good designs available. As I can unconditionally say that mine works great (if time aligned), I'll give you some links:
Tapped Horn Vs. Bass Reflex Case Study - diyAudio
This one has plans:
Keystone Sub Using 18,15,&12 Inch Speakers - diyAudio
A horn extender gave a 3 dB average increase in forward gain all the way down to the LF corner:
Horn Extender/Wave-guide for TH - diyAudio
A word of warning: once you go down this rabbit hole, don't expect to emerge for a while...
Art
