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In the Forum: Horn-Loaded Speakers
In the Thread: The tapped horns: cons, pros and Sound
Post Subject: Looking at the tapped horn further…Posted by Romy the Cat on: 4/29/2009

 serenechaos wrote:
I do not know of importance of enemys death to this topic.

Oh, this is a sheer pleasure but do not call that dirt enemy. He is not enemy but way beyond it, he is the person about whom I have a death-wish as pure self-pleasuring. Think about him like people thought about Hitler and think how pleased some people would be learning that that son of bitch choked to death. Enemy implies a conflict of interests. He is no enemy, in fact I have no idea who he is and what his interest are. However, knowing his actions I sincerely feel that he is out of presentences of any civilized treatment and that he shall be literally exterminated like some kind of virus or very filthy bacteria.

 serenechaos wrote:
I do not know what is meant by “close bottom” or “open bottomless”-- please expound?

I have expressed those views of mine many times and this is one of my major reasons why I am not so excited about use of bass horns for the lowest channel of playback. In the past I wrote in the “Barn Conversion - James' Project” thered:

"The sealed enclosure I call “opened bottom” enclosures. What I mean is that there are no conceptual limitations in lower response. The limitations in sealed box are tactical: how much power you have, how much your drivers will handle, what is the relation of volume and Fs, how driver damped by amplifier and many others. However, there is no self-restricting boundary in there. With any other LF solutions (horn, open baffles, 4th order, ported and so on) there are always strategic limitations by nature of the design… would it be size of the baffle, size of the mouth or tuning of a port). With sealed box you can always burn some power, use the LF section on transition slope or even EQ (with open bottom only) your bass (works very well). With any other solutions (besides sealed box) those “further actions” are not available. Those are some of my motivations why I do not like the idea of bass horns and prefer the sealed enclosures"

Take a look what happed with any bass horn. In order to get proper sound out of any bass horn you must unload the lowest frequency from the horn, the frequency that are not able to be reproduced by this horn. This is a very big subject and I can talk for very long nowadays about the ways how the rule might be “banded”, but unloading of unused bass is very basic objective. BTW, the person who made me to think about it was John Hasquin.  That sharp explicit filtration of bottom knee of a channel is fine if you have another channel follow but if it is the last channel then it not good. Pretend that you have a tweeter with low pass filter. Did you ever try to use any anti-rambling filters in phonostages, those the kill under 20Hz of what they call TT noise and record warp noise? Di you see how it killed everything? So, those systems I call “closed bottom” and there is a sharp and definitive roll of at LF. Take a look what Tom Danley says in his tapped horn: 15 Hz with 24dB/octave of high-pass. You see it is the lowest channel in system and you have 4th order high-pass. I do not like this idea and I would like the lowest channel to have not explicitly restricted LF response, or something that I call “open bottom”.

 serenechaos wrote:
There is a long thread in the subwoofer section of "devil audio" about tapped horns.  John mentioned getting a flatter response than I was able to using the same driver (4012HO definemax) I was working with. I wrote, asking for advise, he suggested adding a inductor in series w/ the driver. 
Also cutting the throat the full size of the driver, not smaller for compression ratio (!!!) 
He has built others since, is now using two drivers per cab; and says it works better. 

I looked @ many designs, spent a while studying Danley's & the patent trying to figure out what was going on with it, and the resonators, etc.

Sure it is all very interesting but to have in an idea about what people are taking about discussing the quality of tapped horns it would be nice to hear one…

 serenechaos wrote:
Size of the THs I built is ~ 16" x 16" x 80". 

…and THIS is the deal-breaker….

 serenechaos wrote:
implementation--ok, here we go; now none of what I said means anything... 
different room, different system... 
mine is all "unfinished/evaluating/work in progress;" experiments--listen, change, listen, repeat at this point... 
only the tapped horns, and "what I use above 10kHz" stays. 
passive line leval crossover, seperate amps. 
This is all building towards:
the tapped horn is to ~70Hz.
a mid-bass horn from ~70 - ~500Hz. 
a low-mid horn from ~ 500 - 1kHz. (what you call fundamental channel)
a high-mid horn from ~1kHz - 10kHz.
a ribbon from 10kHz up. 

Very, lucid system!

So, you have a tapped horns at 70Hz and below. Does it mean that you do not use any high-pass filtration with your tapped horn? You said that you use passive line level crossover and separate amps. So, what is the bottom frequency response of the power amps that drive the tapped horn? Do those amps have any topological restriction of LF that might act at high-filter for you tapped horn?

Rgs, Romy

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