On 3 way speaker design and my path as inquired above......Owned Khorns for my own listening speakers. Lost them per Katrina etc, etc... Years later (but fairly recently actually) and familiar with their quirks, acquired some EV Sentry III's that needed tlc and restoring them with..... It took me about 10 minutes to figure out that D.B. Keele et al had figured out just about everything you needed to know about horn speakers small enough for homes back in 1973 or so. Past the large 120 degree sm120 horn, there wasn't a whole lot to learn. That horn was the whole ball of wax. Point source from 600 to 3500. Aha! a light went on. It took a little more time to figure out that the driver on st350 tweeter variant of the old t35 was sub optimal and you could stick a bunch of other drivers on that little baby ckeeks lens, you would be fine, but why? You could get away with a bit of fudging near or anything above that crossover point. Hmmmm. It took me about a week to discern something sort of nasty, something that actually was untenable going on at around 600 hz, crossover point. From there it took a few weeks of playing around to figure out that almost everything that really counts in a speaker is within the range of 500 to around 6k or so. Below that and above it you can fudge a bit *if* you have a proper directivity horn that can cover that. Those WILL be big horns. Period. Crossovers in the middle were and are a royal PIA. It took a couple of hours after switching the Sentry III over to the incredible power of a digital electronic crossover, to find that if DB Keele et al would have had access to anything remotely resembling a Behringer DCX 2496 they would been doing an even bigger whoopie dance all over the floor just like in the old ad for those things! That unit transformed the simple Sentry III horn loaded and Theil aligned box into something that is and will remain competitive with anything out there......Until it dawned on me that it would be pretty damn incredible if high SPL flat FR and full range was coming from one point source. Well and obviously, hello Diyaudio, hello Wayne P. hello Earl Geddes and finally...... hello Mr. Danley....Holy Grail.....end of trail.
Actually, there might be one of us out here 🙂
I would argue that the baffle of a loudspeaker forms a waveguide. It constrains the directivity of the loudspeaker into 180 degrees. It works down to a frequency that's basically equal to the baffle diameter.
I think it's important to understand this, because a lot of the audio mags wax poetic about the virtues of narrow baffles. And there isn't anything 'magical' about narrow baffles; the main virtue of a narrow baffle is that it raises the frequency at which the loudspeaker will start to radiate into 360 degrees. For instance, a tweeter on a 10" wide baffle will radiate into 180 degrees down to 1,350hz while a tweeter on a 3" baffle will radiate into 180 degrees down to 4500hz.
yeah, but i guess I'm a bit of both and I listen both ways. Yeah I have some friends that are talking about Jericho's, crazy huh? On the curve issue I suppose that with the lack of phase issues, the curve could be anything the heart desires at the crossover right? Ditto on the Hip Hop thing, and that is a big slice of the pie.
Patrick, this is exactly what I was thinking.I was thinking that not seeing a baffle as a waveguide is not being honest with ourselves, simply smoke and mirrors nothing more.
Richidoo, the information above in the long post was incredibly detailed. I am inclined to listen carefully to every word you said, based on that level of detail and insight. Thanks a lot.
My hammer drives both thumbtacks and nails equally well, but my tack-hammer only drives thumbtacks, it has a hard time driving nails. My tack-hammer on the other hand, is a lot easier to carry around.
That is fine, and right on the line.
But as mix engineers, translation is key.
And if we do not use speakers similar to the unwashed "thee", we won't be hearing what "they" hear. Auratones are better than much of the crap passing as "high end", and whatever your speaker of choice replacing the fatiguing Yamaha NS-10 will still be closer to the sound of the speaker the typical listener uses than a Synergy.
It would take a rather large paradigm shift for the average listener to accept a speaker of around 30 x 30 x 30 inches when raised on stuff that makes "bookshelf" speakers seem huge.
Anyway, don't hold your breath regarding DSL doing reference monitors, Mike Heddon knows where the money comes from, and it ain't from that market in big horns, that ship sailed before last century was over.
That said, just soffit mount some SH-50s and EQ them the way you like and alternate with little near fields (like mix guys always have) and tell us how you like it.
Art
Well everything you said, but the Auratones. No longer relavant thank god. back then I used a clock radio. Better choice too in retrospect. I had NS 10's. I truly hated them. I never turned them on. They were there for the clients to see, that was about it. If the tweets ever blew out I could have cared less. Never heard about the Kleenex thing till years later. Always knew they sucked, never drank the koolaid. I was jazzed when I read Tooles report, laughed my butt off. In the 80's I used sentry 100's for everything and guess what? I soffit mounted them . Yeah I know I must use the hated 801's and the assorted 8" two ways for the very reasons you mentioned, but that paradigm is shifting too. What I might actually do in the mastering realm and sort of as a sideshow, is funny, but I might just do it. I might put myself a full on car interior in here (-: What a marketing tool huh? I don't like marketing at all if the results don't translate, but imagine the Hip Hop intensity !!!!! Soffit mount Danleys? Hmmm....the thing is I can't afford them anyway for now. They are not inexpensive at all, but if they are made for this market, the price will come down I think.
Weltersys, A three way box with a two way "synergy" horn to the Schroeder and a direct radiator below would be highly relevant. And small enough too. It's the midrange and associated phase crap that's Fubar on all of these near fields and has been forever.
The point about the synergy technique that seems to get missed IMO is this:
When the HF compression driver sends a wave down the horn, what happens when it encounters the midranges? It will diffract off of them a create HOMs and some rearward reflections. This is never going to be a good thing although it can be minimized. But since it does not exist in a singe driver waveguide it does not have to be minimized.
Also the midranges send sound back down the device towards the compression driver and reflect off of it. This too is never going to be a good thing, but could be minimized.
There is also the mouth treatment and potential diffraction from it.
As with all designs the devil is in the details and only a high resolution polar map would show if these problems are significant in any individual design or not. I have yet to see such measurements. I would love to, or better yet, I would love to do them myself, but that has not happened either. Everyone here is arguing from a "it should work great" point if view, but without real data how things actually work is just a guess.
When the HF compression driver sends a wave down the horn, what happens when it encounters the midranges? It will diffract off of them a create HOMs and some rearward reflections. This is never going to be a good thing although it can be minimized. But since it does not exist in a singe driver waveguide it does not have to be minimized.
Also the midranges send sound back down the device towards the compression driver and reflect off of it. This too is never going to be a good thing, but could be minimized.
There is also the mouth treatment and potential diffraction from it.
As with all designs the devil is in the details and only a high resolution polar map would show if these problems are significant in any individual design or not. I have yet to see such measurements. I would love to, or better yet, I would love to do them myself, but that has not happened either. Everyone here is arguing from a "it should work great" point if view, but without real data how things actually work is just a guess.
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Could you explain what the "in your lap effect" is?
I'm familiar with horns, Bose 901s and a wide range of other speakers. Not sure what this effect is supposed to be, and what its source is alleged to be?
Thanks.
_-_-
So far this has been an interesting read.
Dr. Geddes touched on a question that I have not found an answer for, going back to the days of the earliest Unity horn rollout.
It's completely unclear to me why the LF drivers do not *modulate* the heck out of the HF diaphragms. Even a relatively modest amount of LF energy would wreck havoc with those dainty compression drivers. Even if most of the LF energy radiates out the front of the horn, the interior of the horn still has to become pressurized entirely, there is not going to be a region at the back of the horn with unity or negative pressure (vacuum) except to the extent that there is a period to the pressure for given waveforms as generated by the diaphragms (sound, in other words).
So, I am of course dense, and don't actually know anything, and am at a loss to explain why the LF energy does not impact upon the other diaphragms in a negative way.
_-_-
PS. Both the Unity and the Synergy seem to me to be really slick, innovative designs.
Tom, are you going to have them at the upcoming NY AES??
Dr. Geddes touched on a question that I have not found an answer for, going back to the days of the earliest Unity horn rollout.
It's completely unclear to me why the LF drivers do not *modulate* the heck out of the HF diaphragms. Even a relatively modest amount of LF energy would wreck havoc with those dainty compression drivers. Even if most of the LF energy radiates out the front of the horn, the interior of the horn still has to become pressurized entirely, there is not going to be a region at the back of the horn with unity or negative pressure (vacuum) except to the extent that there is a period to the pressure for given waveforms as generated by the diaphragms (sound, in other words).
So, I am of course dense, and don't actually know anything, and am at a loss to explain why the LF energy does not impact upon the other diaphragms in a negative way.
_-_-
PS. Both the Unity and the Synergy seem to me to be really slick, innovative designs.
Tom, are you going to have them at the upcoming NY AES??
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Thanks for that post, very informative. I haven't spent enough time with the Synergies to get that detailed a listen. You have. Thanks for the very clear explanation.
Earl I was thinking the same thing about the diffraction issues..... I was hoping you'd be the one to bring it up. How would you go about minimizing it, foam?
I have done measurements on a JBL SRX725 horns that does have screw holes in the profile (that is how the driver is attached, which make for a very solid and non resonant throat).
Here are the measurement, with and without covering them (I used foam and duct tape, as I did not have the original cover). Of course those dips cannot be equalized because they are different from a measurement angle to another.
Tom said putting the holes along the edges of the horn profile, like it is done in the Synergy, reduces the problem.
Here are the measurement, with and without covering them (I used foam and duct tape, as I did not have the original cover). Of course those dips cannot be equalized because they are different from a measurement angle to another.
Tom said putting the holes along the edges of the horn profile, like it is done in the Synergy, reduces the problem.
Attachments
Bill Waslo posted some measurements of the effect of covering the woofer holes in his synergy horn (post #101) in this thread
DIY Synergy/Unity spreadsheet
DIY Synergy/Unity spreadsheet
A horn is very sensitive to aberrations in its walls. How would I resolve the problem of mids in the walls? Well if I didn't need to put them there then I wouldn't. But for Tom to get the kind of SPL that he is looking for he has to. Given that, one would have to experiment with ways to minimize the negative effects and maximize the positive ones. The details are what matters.
In my own designs I have found even small, and I mean very small, mismatching of the waveguide to the compression driver can have a large effect (as shown in the photo above). So I cannot see how big midranges in the walls will not have a substantial effect.
In my own designs I have found even small, and I mean very small, mismatching of the waveguide to the compression driver can have a large effect (as shown in the photo above). So I cannot see how big midranges in the walls will not have a substantial effect.
Thanks - clearly confirms that the effect is real. I'd still like to see some good polar maps!! That would even be more instructive.
Oh no not I. The more "forward" a spjeaker the better. I'll explain it this way. Up there on the pole you can see it ok, but In you lap better. It's called the stripperaural effect.
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