ZilchLab said:
The gedlee thingee must be a horn because it has gain. And it does use defraction so it can't be a waveguide.
Clue: Measure driver and compare with and without thingeeThe epitimy of defraction - Sounds Great!
Robh3606 said:"They do have a foam lining at the edge to minimize diffraction..."
And they are not the first on that count. This should look familiar it's a Urei 801C horn.
Rob
My beefy PAS 15" 2580 with 2" exit large format compression driver coax (I call it Super UREI) has the foam on the horn lip. It seems to help most at the 800-1000 Hz crossover overlap
You can get the foam lip from PAS for like 15 dollars if yours is missing
Jmmlc said:
Cut-off is a concept from Horn Theory (a weak one IMO) that does not exist in Waveguide Theory. There is a coupling of the input impedance with the angle and this is something like a "cutoff" but no real "cutoff" exists. And of course this phenomina doesn't exist in the real world either. No horn or waveguide exhibits a true cutoff - only in theory. All devices transmit all frequencies, with more of less gain. Cut-off is a meaningless concept to me.
Now the HOM do have a true "cut-off" a frequency below which they are purely imaginary waves (mathematically) and thus propagate with an exponential damping - this phenomina is called evenescent waves. But the main wave has no such effect.
P.S. Nobody really answered *except in riddles* if that device can be filed under ''WG'' or not.
salas said:
The system -6dB point is driver dependent. You could talk about the 1/2 real part of the impedance point. This changes with coverage angle, so what coverage are you interested in down to this frequency? And oh yes, to control down to 160 Hz. the mouth needs to be about 10 feet across.
The whole question of cutoff at 160 Hz is, IMO not a very useful one since the device would have to be huge to work. And if it is too short then its performance is dominated by mouth diffraction and internal resonances and "cutoff is just a paper exercize.
No compression driver goes down to 160 Hz. anyways.
I mean the whole question is unrealistic.
Hello,
Compression drivers which can reproduce 160Hz exist:
As an example give a look to:
http://www.e-speakers.com/Pdf/Goto.pdf
see reference SG505 : 100Hz-8kHz
and reference SG-143LD : 20Hz -500Hz (
Also, I gave recently that link to the response curve of an Azura horn having a 160Hz cut-off
http://www.azurahorn.com/6681_on_160.pdf
I rewrite my question without any reference to "cutoff": what are the dimensions of a waveguide able to reproduce 160Hz at the same SPL that a Tractrix horn(e.g) will give?
Best regards from Paris, France
Jean-Michel Le Cléac'h
Compression drivers which can reproduce 160Hz exist:
As an example give a look to:
http://www.e-speakers.com/Pdf/Goto.pdf
see reference SG505 : 100Hz-8kHz
and reference SG-143LD : 20Hz -500Hz (
Also, I gave recently that link to the response curve of an Azura horn having a 160Hz cut-off
http://www.azurahorn.com/6681_on_160.pdf
I rewrite my question without any reference to "cutoff": what are the dimensions of a waveguide able to reproduce 160Hz at the same SPL that a Tractrix horn(e.g) will give?
Best regards from Paris, France
Jean-Michel Le Cléac'h
gedlee said:
Jmmlc said:
What you are asking is so far from anything that I would consider doing that I don't want to respond. I just be guessing and thats not something that I like to do.
Looking at those links we are not considering the same things or even close to the same designs. For a compression driver to go down to 160 Hz its excursion would be excessive resulting in a very low MaxSPL or a lot of distortion. I don't see polar responses for those horns and thats far more important to me than an axial curve ploted on a 120 dB scale.
Show me a system response that can compete with what I have shown and we can talk. Otherwise the question is academic to me.
Hello Earl
That's OK for me but most probably this will reinforce among us the idea that low frequency domain is not something to which waveguides are devoted...
And as I feel my questions are not welcome, I stop to bother you on that thread.
Best regards from Paris, France
Jean-Michel Le Cléac'h
That's OK for me but most probably this will reinforce among us the idea that low frequency domain is not something to which waveguides are devoted...
And as I feel my questions are not welcome, I stop to bother you on that thread.
Best regards from Paris, France
Jean-Michel Le Cléac'h
gedlee said:
Jmmlc said:
I have stated many times before that I don't believe that horns or waveguides have any advantages when the device becomes too small to control the directivity. I also stated that your simulations were wrong and hence there simply is no data to compare my designs with yours below about 800 Hz. I WILL compare mine to yours in any frequency region in which mine were designed to be used, but you setup the comparison in your favor when you go outside of my design criteria.
I have no problem with your asking the questions, they are all welcome, but I am not going to do an elaborate analysis that I don't see as meaningful.
I'd love to discuss the NEED to take a waveguide down to 160 Hz that would be meaning full.
As I have said, I focus on the system design rather than any single component. And I find that the best system designs do not require a waveguide below about 800 Hz. My justifications for this are well published and I don't see any flaws in the analysis. Nor have the personal reviews of my approach highlighted any issues.
salas said:
Possibly, but thats pretty much what I do now. The directivity control of the 15 starts at about 500 Hz - its down by 10 db at that point. Going lower "might" be positive, but its what would have to be compromised to do it that would be a concern for me. I would rather move the crossover higher in frequency than to take the waveguide down lower than it was designed to control. That equates very simply to size. What size can you live with and I'll tell you how low in frequency I can control the pattern and what the woofer size and configuration has to be. From what I can tell the Summa was a good choice for me, but not very many other people. They want smaller.
But in a custom design I could do anything that you want.
Variac said:I believe that DIY Audio people can tolerate larger than the general market
Their Spouses are either immunized to monstrous creations appearing in the house, or they are long gone.....
Probably true.
I have never understood WAF. I think that it really means "I don't think that they look cool, so I'll blaim it on my wife" - they don't want to admit how strongly their impression is weighted by what they see. Because how a speaker looks SHOULD NOT have anything to do with how it sounds.
I just say - put them behind a curtain and be done with it. When they don't want to do that its clear what the priorities are.
Robh3606 said:"Their Spouses are either immunized to monstrous creations appearing in the house, or they are long gone....."
LOL yeah if I didn't have a basement something would have to go.
But honey the MDF looks so good next to the china closet. It matches the drapes.
Rob
Why anyone would want to share a listening space with their wife is completely beyond me. Only if there just isn't enough room for each to have their own space would this make sense. But I don't think that I could survive very long in an abode that didn't allow for the couple to each have there own space.
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