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In the Forum: Horn-Loaded Speakers
In the Thread: Macondo Frame modification.
Post Subject: Horn is not Saddam – I feel it could be hanged.Posted by Romy the Cat on: 12/27/2006
| hagtech wrote:|
|Romy, I don't know what it is, but something bothers me about the way the upper horn hangs. All other drivers are supported from bottom, that one from the top. This is just gut, but it doesn't seem right to me. I get this sick feeling of wobble and resonance. Perhaps merely irrational thoughts.|
Is there any way possible to offer a support from the bottom? That is, without disturbing the gas field in front of the tweeter. I don't think it is as much an issue of top or bottom as it is that large moment of inertia I see with the tall stand.
Well, it is rational thought, I did think about it. Let look at the subject deeper.
Are any ways to support the upper-horn from bottom? There are 3 ways that contemplated in past. It was use of thin tripod-like tubing coming from the upper-horn all the way to the bottom (similar to what Avantgarde did). This would put the speaker inside a virtual pyramid. I do not like how it looks like, not to mention the presents of one and a half rods ahead of the tweeter. Another option that I contemplated was use of two sides, similar to what Cessaro GAMMA does. I decided do not do it as I would like to keep HF and MF horns as free-hanging as possible because I feel that proximity of any boundaries near horn mouth screw imaging. The third way that I was thinking was to make the tweeter and the upper-horn frame integrated. It would require an enormously strong enclosure for tweeter and very-well designed tweeter-frame. I am not settled with tweeter, an nowadays a new custom tweeter is being built for me. Theoretically after I get the tweeter and if it will perform up to the demands then it would be possible to contemplate the tweeter-frame integrated design. Still, whatever it might be it should connect the tweeter from it’s back only… it is EXACTLY what I a doing now anyhow… so, I disregarded the idea of making Macondo as “a pyramid of the horns” and decided to hang my upper-horn.
Let look what we have as “the problems”. The upper-horn is 600-1000Hz, and it is a compression drivers…. means relatively high frequency, very low exertion, low mass, low inertia. The upper-horn I made think (as you can see at the picture in the beginning of the thread). It is approximately 30 pounds + ~12 pounds of the driver. Now, correct me if I’m wrong but as far as I understand it - any theoretical resonance-induced by swinging would act against the center of mass. The center of mass is far ways on the horizontal level that makes the total applied mass of the horn assembly way over 200 pounds. In the past, contemplating all of it I made soft suspension of the upper-horn in its horizontal arm. It was immense complex setting where the horn was handing on 2 rubber suspenders. Interestingly that the decupling produce ABSOLUTELY NO DIFFERENCES to the actual SOUND OF THE HORN and I decided to go for hard-coupling between the horn and the arm. I also trued adding the additional 150 pounds atop of the horn (5 bags of the led shots) and it HAD NO SONIC EFFECT…
So, what I concluded was that any resonances that might take place in the “handed horn” are imaginable or negligible. At least so far I was not able to hear the problems attributed to the swinging resonance…. So, I do not care about it anymore, and unless I head something that I find is “not right” I will not dig deeper. Generally purring a statescope on the horn says a lot what is doing on… The “hanged horn” responses via statescope identically to the same horn sitting on carpet. So, as they say out of sight – out of mind….Rgs,
Romy the Cat
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