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In the Forum: Horn-Loaded Speakers
In the Thread: Idea of a 3way horn system
Post Subject: Some “uncomfortable” truth about horns.Posted by Romy the Cat on: 11/7/2006

 Dominic wrote:
romy-"A horn is not a sensitively boosting machine or the pressure impedance transformer but an equalizer and equalizer only. Consider a horn as a Dolby decoder"

But isn't it really all of the above. it's by means of all the other aspects that you end up with the equalizer.

Good catch, Dominic. It was a “loaded statement” on my part and I thought that it will be missed.

In the given case world “equalizer” has much extended meaning then just equalizer. The important thing in it - mentally go away from a concept of “impedance transformation”. You see, they are many books, articles and stupid programs are written about horns and all of them understand horn as a mechanism of propagation of acoustic pressure. It is fun to be able to circulate a phase shifts in each single point of a horn’a belly and it is fun to dive into lengthy discussion about the shaping of the wave front but the problem is that none of those “theories” ever were able to explain Sound that is coming from a horn/driver assembly.

It is virtually imposable to say what driver should do in order it to be sound good through a horn. I know, a lot of people would disagree with me and will recite the T/S characteristics… However, they can stick their recitations right into their asses. When they manage making musical and problem-free sounding horns installations instead of a pile of conceptual honky garbage then their lip-movement will be less meaningless for me.

So, we build Sound not Horns and therefore there are no impedance transformers. There are drivers and there are horns, the horns that make our drivers to sound more or less “compensated”. It is about balance, it is about sensibility, it is about prudence, it is about self-moderation, it is about having a very clear and very definitive vision what you want to get out of horn’s sound. And it is of course about your ability to employ different techniques in order to accomplish the Sound. Very few horns installations perform alike. For instance Bruce Edgar never was able to make two identically sounding horns and as I can see the subject it is perfectly OK. The multi-channels horn installations are live and vibrant organisms and as you said: “lot of things that happen when you put anything in the path of a sound”. Those “lot of things” are not necessary in compliance with stupid conceptual ideas: like boosting acoustic pressure by use of the front chambers.  The theory of pressure propagation explains the front chambers as a benefit however, the front chambers violate Sound. Here is why I like a mental picture that a horn is an equalizer.

Yes, a horn equalizers sound of a horn’s driver. Each horn, or each profile, of each mouth rate make equalization differently and each driver has own ability to be equalized. What is important, however, is do not take this equalization ONLY as juts frequency flatting but rather as equalization-normalization-harmonization. In addition, yes, a horn loading will boos some sensitivity (depends of many criteria) but it is secondary. The primary thing is that a horn should embrace the best that the driver has and after exposing the driver’s output to own equalization-normalization-harmonization it should bring it out the Proper SoundIt is imposable to make horn to sound well by juts looking at the horn theory (mostly existing theory is mistaken, completely obsolete or not applicable at all). To do so, would be similar to a woman who applies make up to her face but whiteout looking in the mirror… Imposable? Yes, imposable but it is exactly how most of the people approach horns.

So, why I propose that horn rather equalizer then impedance transformer? A transformer, from a very simplified abstract point of view, is self-contained devise that do not care about outside world. It has a transformer ratio and you just apply voltage to the primary and receive voltage at secondary. The inner behavior of a transformer will not change because the deeding AC was different. Yes, it will be different transformer for different frequencies or for pulses but still it will be the same basic operation: to render the transformation ratio. With a filter it’s slightly different because a filter does not have a self-contained propose. For intense in RIAA, Dolby or in the Tape EQ cases you need to know very precisely how your signals was the EQed in order to properly de-equalizer it. What I like about it that it set a reference to abstract “final objective normality of result” and forces a persons to look at the concluding Sound as applied objective outcome instead as at the outcome of some kind of semi-algebraic meditation about acoustic pressure. Pressure is good what you design some heavy duty hydraulic pressure machines but it has nothing to do with Sound. Even the acoustic pressure and acoustical Sound are frequently the players of the different teams…

Romy the Cat

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