If this is finite element type analysis, the size of the mesh governs the resolution, not the screen resolution governing the analysis resolution, afaik. I'm not sure what the 81x81 refers to in this case, the whole mesh or the mesh per some unit area??
No it is the drivers that are horrible as most compression drivers are based on breakup resonances to get the SPL.
I use waveguides on my AMTs, but not to give SPL gain..
Aside from 3 or 4" diaphragms above 10 KHz, I don't know where you're getting this information. 😕
I don't know where you are getting your data, but that is simply not true. A 1.75" diaphragm in a 1" compression driver is a rigid piston up to > 10 kHz, above which I don't really care.
Ive posted some examples of this on the forum
For instance the diaphragm on the Celestion CDX1-1425 is half the size of the b&c de250. The reduction in size pushes the breakup to about 20khz. This yields more extended response.
The breakup is easily seen in a CSD plot
As Geddes noted, if u can't hear 18khz, its probably not a big concern.
Thanks Patrick. But is this the same as what Ray is claiming? That breakup resonance is used to get the SPL? Or is it just used to extend response?
Both.
Check out the Bruce Edgar articles on volvotreters site.
Easiest way to see the effect is in a CSD plot. Ribbons DO decay faster than domes.
There have been lots of papers on how the breakup of a compression driver dome (and surround actually) can be used to extend the response, but these all referred to frequencies above 10 kHz. There simply are not any significant breakup modes in a 1.75" diaphragm below 10 kHz. They all start to loose it above that, but who cares.
Hmmm. I don't see any significant problems from 1.75" diaphragms. There are obviously problems with larger diaphragms though. However, where constant high output levels from a single driver is required (outdoors, etc.), I still think a 3" diaphragm is a good compromise. Even here, breakup doesn't seem to me to be significant until about 12 KHz or so. For personal use at home, a 1.75" diaphragm will do the job just fine.
+1
Totally with you on that one. It amazes me how much pertinent info/research is dismissed by experts here, when the data says it all.
As far as horns go, their path length and resultant delay is something unavoidable and in my humble opinion makes them unsuitable for full or extended range operation.
OK, but then instead of "who cares"... why not just cross over to a proper (horn, or ribbon) tweeter at around 7-8kHz, thereby reducing the output from the breaking-up compression driver? The supposed "complications" and "non-ideality" of the crossover (phase issues etc.) are no longer relevant at those frequencies, where the human hearing systems is incapable of detecting phase; OTOH, the reduced distortion should be audible.
I think when a tweeter is not added, it is mainly because of cost considerations, not because forcing the compression driver to cover all frequencies up to its extreme limit is the best approach, all things considered.
Marco
No AllenB,
I just believe that, depending on a couple of factors, horn path length is problematic at lower freqs.
BLH being the worst offender, and front horns with a long path length relative to its accompanying woofer cone depth.
Same goes for TLs which attempt to amplify rather than LP and attenuate the rear wave.
But its only my opinion lol
I just believe that, depending on a couple of factors, horn path length is problematic at lower freqs.
BLH being the worst offender, and front horns with a long path length relative to its accompanying woofer cone depth.
Same goes for TLs which attempt to amplify rather than LP and attenuate the rear wave.
But its only my opinion lol
Fair enough mondogenerator. I guess that I just see it as being for the most part possible to find a way.
By the way, I kind of see back loaded horns as being a different beast, and I don't tend to use them in multi-way.
By the way, I kind of see back loaded horns as being a different beast, and I don't tend to use them in multi-way.
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Flawed Horn Model Assumptions:
Some of which include:
a) that the horn is of infinite extent (mouthless),
b) that it is free of transverse radiation modalities, and
c) that the isophase surfaces are plainer.
What remains unaddressed is the transition into free space or the confines of an enclosed venue. Klipsch addressed this issue for enclosed listening spaces at low frequencies. Le Cleac’h for high frequencies with a tractable isophase surface geometry. And, the addition of foam and the hyperbolic profile to suppress transverse modes by Geddes. Profile enhancement continues using shape optimization technology [1].
[1]
urn:nbn:se:uu:diva-44639: Shape optimization of an acoustic horn
http://www.it.uu.se/research/publications/reports/2002-019/2002-019-nc.pdf
Regards,
WHG
Some of which include:
a) that the horn is of infinite extent (mouthless),
b) that it is free of transverse radiation modalities, and
c) that the isophase surfaces are plainer.
What remains unaddressed is the transition into free space or the confines of an enclosed venue. Klipsch addressed this issue for enclosed listening spaces at low frequencies. Le Cleac’h for high frequencies with a tractable isophase surface geometry. And, the addition of foam and the hyperbolic profile to suppress transverse modes by Geddes. Profile enhancement continues using shape optimization technology [1].
[1]
urn:nbn:se:uu:diva-44639: Shape optimization of an acoustic horn
http://www.it.uu.se/research/publications/reports/2002-019/2002-019-nc.pdf
Regards,
WHG
I think we are probably in partial agreement. The decade rule is one i wouldn't break, and suffice to say i would likely cover significantly less than a decade. E.g. something like a 4 way system, 3way at a push.
In a two way going from sub 500 hz seems to my eyes a compromise too far. To me 500-5k horn mid and a horn top makes more sense. Even better if the tops are horn loaded ribbons ��
But that's still a full decade...and going 4way leaves awkward xo points.
In the end all concepts are flawed to varying degrees, its just a matter of determining which flaws youor i can live with.
To qualify myself, my opinion is just that, an opinion. Neither right nor wrong. But its my reasons for never building a horn system. Lack of distortion is the most attractive thing about horns, DI next (presuming the optimal flare etc). Basically, separate horns for mids and highs are attractive to me, but midHF horns are not. Abberations at 12k+ are pretty abhorrent to my ears.
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That is simply not the case. At those frequencies the wavelengths are very short and the spacing between the sources is very large. The lobbing problems are enormous. That is a bad idea. The use of a single source is by far the better approach. It has nothing to do with cost.
I love that point of view - its my opinion so it can't be wrong.
No, your "opinion" can be wrong if its a quantifiable question. Opinions are valid for subjective things like art, but science is not subjective.
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