i am really confused as to what i apparently don't understand and am left wondering how to move forward from here.
when someone who's knowledge and work i respect treats me in what seems to be a rather condescending fashion it makes me wonder if it's at all possible to re-mediate the situation.
i guess that i will have to review statements in several threads to see where i have potentially mis-understood statements that have been made in order to ascertain where i've erred.
when someone who's knowledge and work i respect treats me in what seems to be a rather condescending fashion it makes me wonder if it's at all possible to re-mediate the situation.
i guess that i will have to review statements in several threads to see where i have potentially mis-understood statements that have been made in order to ascertain where i've erred.
Who ever stated that distortion in a horn was not audible? I must have missed that.
I think that you are the one who has the condescending tone, remember your jab at me started all this and now you want to play the abused?
You clearly have misunderstood things, that is what I am trying to point out. I'd be happy to refresh the conversation, and try and clear up your confussion, but only back at the original thread (since you are trying to hijack this one.)
Can't agree on that one. My Synergy variations are only 12" deep, including the bass cabinet! And they are 90degree horizontal coverage in the waveguide controlled band, I personally wouldn't want a more narrow pattern horizontally (vertically, though, I probably would). And you don't really need hardly ANY space to work in -- I now have mine setup so the listening position is about 7ft from the mouths, being nearly point-source there is no need to get back and away for integration. You do want several feet of space behind the listening seat for best results, but that is true of all speakers I know of. The only thing that might make them unsuitable for home listening is the appearance of the commercial models (too industrial for most interior decorators, I suspect).
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I have the tweeters in mine crossed over at about 2kHz, due to the choice of the tweeter driver. I went with CDXi-1445 because it has a 30 degree throat angle, wider than most, and less different from the angles in the horn -- Tom has mentioned that at very high frequencies, the coverage angle is already largely determined inside the driver itself before the wave even gets into the horn. The CDXi-1445 also has a very short throat, which helps with getting the midrange ports close enough (does make design of the horn itself tricky squeezing everything in, particularly with +/-45 degree walls).
That driver also has rare output to 20kHz, not that it probably really matters (doubt I could ever hear that high, certainly not now at my age). Probably that is largely diaphram breakup, anyway. But it looks nice on graphs, though!
That driver also has rare output to 20kHz, not that it probably really matters (doubt I could ever hear that high, certainly not now at my age). Probably that is largely diaphram breakup, anyway. But it looks nice on graphs, though!
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Could it be said that 'waistbanding' is the product of a diffraction mode that effectively skirts the beam and cancels radiation at the edge? where a radius would disperse the pressure reversal at the cost of widening the beam.
Is the secondary flare intended to mimic a radius or is it a superior compromise (if frequencies are low enough).
Is the secondary flare intended to mimic a radius or is it a superior compromise (if frequencies are low enough).
I am not sure that I would describe waist banding that way.
At some point the waveguide is too small to control the directivity and so it narrows and then widens as frequency goes lower. Then as the frequency goes higher it widens once the waveguides mouth becomes sufficient large to control it. All devices will do this, but operating above the waistband frequency will avoid this. Of course, with a broad band device like the synergy it cannot be avoided.
At some point the waveguide is too small to control the directivity and so it narrows and then widens as frequency goes lower. Then as the frequency goes higher it widens once the waveguides mouth becomes sufficient large to control it. All devices will do this, but operating above the waistband frequency will avoid this. Of course, with a broad band device like the synergy it cannot be avoided.
This has been my understanding of why waistbanding happens.....though I don't think I would have been able to articulate it that well. Does Keele explain it in his paper "What's so sacred about exponential horns"? I ought to revisit that.
Maybe I'm dense, but that doesn't explain why the waistbanding occurs, only that it does in fact occur.
I had the thought to model it in hornresp and compare the relative power vs beamwidth to maybe identify whether any power is being lost through cancellation.
I'd have to isolate driver bandwith related effects, acoustic impedance effects, and separate the axial mode from the alleged higher order one (or more), and it's enough to put a person off their lunch.
The way I came to suspect this is by viewing wavefront simulations such as the sandbox in hornresp but I don't find it conclusive.
I'd have to isolate driver bandwith related effects, acoustic impedance effects, and separate the axial mode from the alleged higher order one (or more), and it's enough to put a person off their lunch.
The way I came to suspect this is by viewing wavefront simulations such as the sandbox in hornresp but I don't find it conclusive.
I can get apparently good results with a hypex T=~3. I can supply an appropriate throat wavefront shape.. but what will work for this particular aspect, will be a profile that permits me to terminate it onto a flat baffle without pulling the shown beamwidth plot apart.
I've considered going sharply onto a baffle (bandwidth for this horn is 200-700Hz), but I'd rather look for a smooth profile that achieves this.
I've considered going sharply onto a baffle (bandwidth for this horn is 200-700Hz), but I'd rather look for a smooth profile that achieves this.
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To me the "why" is because the mouth gets too small to control the radiation. To get more detailed than that we would have to look at the radiation modes for a spherical wavefront and see what is happening there. Basically at sufficiently high ka the wave radiates straight ahead regardless of the ka value - like a flashlight - but in the region of ka = 2 there will be some diffraction of the wave at the mouth which causes a reduction in the beam width - just like a piston source has. Below ka = 2 the mouth is basically just a flat piston and the beam will widen as the ka value goes down.
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Because I prefer single speaker mono I desire boundry effects to give me the sense of the room I am listening in, having my head inside the horn provides a very amusing mental image though !
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Art, agreed on all fronts.
Earl, I would point out that one main difference between co-entrant and a Synergy design lies within the interplay of properly tapping into the horn for each bandwidth, maintaining horn loading over a much broader range for all driver sets.
From what I've seen of the other co-entrant devices lose this facet of operation, figuring out merely how to get the devices into the same waveguide. The other impacts in terms of phase and distortion reduction are beneficial as well.
Scott
Bill, agreed on all fronts...they are simply the highest output most coherent headphones I don't have to wear. I stopped calling them high output mini-monitors because even mini-monitors aren't as precise as a Synergy. They sound very nearly the same if your head is in the horn...or not.
Scott
Hmmm...I'll have to go re-read the Keele paper on exponential horns...where he goes into waistbanding skirts in detail. I hadn't thought of it that way...though the commercial Synergy designs seem to radius the angle change more than most DIY...including my own. I might do that on my next try to see what the advantage is.
Scott
I've seen many people put their heads in mine. Including myself. They really do sound very nearly the same. I've also seen people put their head into my center channel speaker to ensure that it is indeed off. The center image is so precise that they don't believe me when I tell them the center channel is off and they are listening to two channel stereo. They'll point at some space behind the speaker and say:
"But Holly Cole (Or Diana Krall) is right *THERE* <points more emphatically>"
I'm like...ummm...go put your head in the speaker?
I had one person take the remote from me while they did it so they knew I wasn't changing it as they stuck their head in the speaker.
Scott.
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