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JLH wrote:

One of the things that is not talked about with tapped horns is they are more directional than a normal subwoofer. They do not excite the entire room with omnidirectional sound.

 John, 

this is serious drawback I my book, even though you told before that the tapped horns become non-direction below 80Hz. Despite I do not argue that you might have the targeted SPL level I do not know how useful would be this SPL if it does not couples with room.

 Any LF acoustic system has two SPL levels: the SPL of pressure and the SPL of tone. (People do not talk about it as this is an absolutely alien concept for audio people. The unfortunate who sell far-machines to audio morons did not pre-sell and did not implant this issue into the feeble minds of the audio hoodlums and thankfully I write about it cryptically and marketing industry idiots do “get” it). With many LF solutions that I do not appreciated the pressure rises faster than tone. The pressure also reduces with different speed in relation to tone. It is not the attack and decay or room reverberation decay - it is a different subject. It has more to do with heating the correct SPL number and with having us as the listeners the practical benefits from specific pitch in musical information that exposes itself at given SPL. I wrote about it before, impaling that there are some listening techniques that allow differentiate the SPL pressure and SPL of tone.

So, in what you say about tapped horns it sound to me as the tapped horns do have the problem with pressure vs. tone.  It was very much expected by me, let me to explain why. There is a pattern in the pressure vs. tone subject that I observe. Being familiar with many many many LF solutions and implementation I was able to observe that the targeted lowest frequency has to be in accordance with lower frequency radiation surface. There are zillion solutions how can get more bass from smaller exerting surface, most of them would do right pressure SPL. However, the more misbalance between the size of the “exerting surface” and pressure SPL the more we have pressure SPL rise faster than tone SPL, I can bring as evidence very many famous models . BTW, this pattern is reversible: with higher targeted lowest frequency the pattern works compliantly and this explains why in some cases the pressure SPL marks let say 100Hz but the tone SPL impressers a listener as it was 40Hz.

So, with tapped horns we are in very disadvantaged situation to begin with as we have very harrow radiation hole and very low targeted lowest frequency for the size of this hole. This is in a way a recipe for “pressure SPL vs. tone SPL” disaster.  What I would propose you is trying to use the tapped horns intentionally non-directional with intentional 3-5msec delay. You might for instance try to reversed you LF listening arc and turn your highly  directional tapped horns in opposite direction from you listing spot, letting the tapped horns to work “off the wall”.  If your upperbass channel is good enough then it might be interesting. In particularly it might be interesting to play in THAT configuration with low pass on the tapped horns as it will not be only moderate the frequency but also the virtual delay. There are some further tricks that you might do in this work “off the wall” configuration: you might put in the end of your room, right at the bouncing wall a subtraction channel but this is another subject….

Again, all of it juts my thinking on the subject that is NOT based upon the tapped horns experience. Sure, sitting in the same room, listening the same inhalation and comparing notes would be more productive…

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