No. It's not audible at home levels....or really loud home levels...or really really loud home levels.
Scott
Like Bill I'm not sure what your asking here.....I've created two sets of Synergy horns....one of which has a 22"x22" mouth and a 60x60 coverage pattern. They are literally the best imaging speakers I've ever heard...and people who hear them tend to agree. I've had MANY instances where people get up and stick their head INSIDE my center horn to make sure it's not on during stereo listening sessions. Sometimes multiple times in the same session...the center image is that precise. Unlike many of the time domain accurate multi-way speakers (Dunlavy, Theil, etc...) the image and tonal balance does not collapse with a few inches of head movement. It stays very strong and good over a range of listening positions.
Scott
That was not my question.
I just wanted to know if the woofers have measurable influence on the tweeter. I ask this, because the coupling may be different then in a conventional design. The question of audibility comes later.
I have elaborated a bit more in post #393
I am confused now and now trying to understand what benefit can synergy horn bring to a normal living room over a large 2 way using large SEOS or Dr Geddes OS waveguide.
Because my earlier understanding wrt vertical pattern control freq of synergy horn doesn't seem to be true
, as pointed by Bill.[I know.. I was the one who asked for DIY project from Tom
]Waveguide based speakers, at a sufficient distance, should allow sufficient space for head movement, even vertically, isn't it ?
And vertical polar irregularities due to 2 driver design can be pushed out far enough, with right crossover, right ?
That was not my question.
I just wanted to know if the woofers have measurable influence on the tweeter. I ask this, because the coupling may be different then in a conventional design. The question of audibility comes later.
One of the things that I think I've read that Tom does in the commercial designs is put a small value inductor in parallel with the tweeter as the very last element. He does this to provide back EMF damping on it so it's not getting shoved around by the pressure from the woofer. Clearly it could be an issue in ultra-high power applications. I can try and set up a test with my home sized/powered designs but I'm not sure I'll get anywhere close to the pressures needed to get something measurable. My "big" horns have 4 Dayton Classic 8" woofers at a whopping xmax of +/- 3mm linear. My "little" horns have 4 TC14SG49-08 5.5" woofers....at +/- 4mm xmax if I remember correctly. Both will blow you out of the room.
For the first year after I built the big horns I listened with a SPL meter at my side...they were so clean I would have no clue how loud they were.
Scott
How much IMD is too much...and at what listening level? I've measured one of my horns...to the best of the ability of my equipment, but I'm wondering where you put the bar? ;-)
My living room is about as small as it gets. There's four of us here, in 1250'. (The joys of living in the second most expensive city in the United States.) Tom's Synergy horns sounded great in this space.
If any of you are interested in 'try before you buy', check around for prosound stores. I found two companies in my city that rent Synergy Horns. I offered to buy this pair but they never returned my email.
As far as sufficient space, I would say, that you can avoid this problem at the seating area for the most part.
Having a lot of experience with the 2-way design it is one area where the Synergy should be expected to work better and that is in the vertical polars right at the crossover. The 2-way will have to have nulls - one up, one down. The synergy should not do that.
However the 2 way is likely to have better pattern control in almost all other ways due to its uncompromised waveguide, - holes in the walls would generally not be a good thing. Which is the better tradeoff I don't think that anybody knows. Tom will always opt for the higher power handling, I for the cleaner polar response - that's what we do and why we do it that way.
Thanks for the photos, Patrick. I have not heard the Synergy in a room that small, although I tried to get a pair for Hi-Fi testing while I was still on the East Coast.
Also not been able to hear the Syngery next to a Gedlee product. I don't think it would be a fair fight, but they are meant for different things and spaces.
Also not been able to hear the Syngery next to a Gedlee product. I don't think it would be a fair fight, but they are meant for different things and spaces.
The (an?) advantage of the Synergy is that you can have one horn covering from moderately low to very high frequency, a standard horn can't cover near as much bandwidth, and due to the required dimensions for narrowing directivity, that forces the other drivers apart. Below where the horn stops controlling directivity, it keeps the apparent source at the same point as at higher frequencies, which is what I think appeals to me most, it never sounding like there's a speaker there, sometimes difficult to believe that's where the sound originates. Whether that effect matters if you can still get down to under 1kHz in one usual horn and have the rest in a separate driver is debated. But one should never assume that you hear only the sound coming from direct path, energy from other lobes will still get to you through reflection. Directivity should help swamp some of that out though.
Disadvantage of the Synergy is the ports in the horn walls, which certainly won't help in keeping diffraction low. How sgnificant that is is also debated. I hear nothing objectionable in mine, but Ive also never heard one of Earl's speakers, much less side by side with a Synergy. I also don't play at very high levels, so the diffraction effect might only be apparent when louder.
Disadvantage of the Synergy is the ports in the horn walls, which certainly won't help in keeping diffraction low. How sgnificant that is is also debated. I hear nothing objectionable in mine, but Ive also never heard one of Earl's speakers, much less side by side with a Synergy. I also don't play at very high levels, so the diffraction effect might only be apparent when louder.
Agreed on all parts. Though...I've listened at blistering levels without even realizing it...so I'm not sure that higher levels will bring out an issue with properly designed midrange/woofer porting.
One thing to note is that the concern over the holes in the walls of the horn is most likely overstated. I've done some measurements where I did a frequency response sweep of the compression driver in a synergy, with and without the midrange holes in place. ( I had taped over them with .005" thickness masking tape.) I could measure no difference...if I had done the ports correctly. Too wide and there was a measurable difference. That's why many of the commercial Synergy horns have tear drop or elliptical/extended hole bass taps for the woofers.
I did have a couple prototypes where I didn't get the taps correct and there was a measurable difference in the compression driver or midrange based on the midrange or woofer port placement and size.
Scott
My living room is about as small as it gets. There's four of us here, in 1250'. (The joys of living in the second most expensive city in the United States.) Tom's Synergy horns sounded great in this space.
If any of you are interested in 'try before you buy', check around for prosound stores. I found two companies in my city that rent Synergy Horns. I offered to buy this pair but they never returned my email.
This might be the only picture I've ever seen with a Synergy and a Geddes design side by side. I'd love to try that one day.
In the mean time I'm going to go listen to my DIY Synergy's and giggle into my whiskey. ;-)
Scott
Same here. I made three gorgeous looking wood veneered Synergy horns, very exactingly cut and built, but decided to "improve" the mid port positions more into the corners... but farther away from each other. What a mess, I couldn't get a smooth response from them and the off-axis response was miserable. They've since been plugged, smeared with wood putty, redrilled, generally used as test mules for experiments now. Lesson learned.
Wouldn’t the SEOS like waveguide help here, as the nulls would be outside the narrow vertical pattern determined by the asymmetric waveguide (as compared to OS waveguide though at cost of vertical pattern control freq) ?
But I get the point that synergy would be cleaner implementation in this respect.
This is also where I would like to apply your question “Whether that effect matters” , based on directivity pdf by Dr Geddes for the range 200Hz-1kHz and the ear’s sensitivity to reflections and timing aberrations. Though I realize that this would apply to waveguides beyond certain size as well..
Yes. This would be a difference which I missed earlier.
And if audible at the intended listening distance and below 1 kHz, this difference would be welcome.
I guess it would be even more beneficial in nearfield, though neither of the 2 designs (2-way with large waveguide and synergy) are intended for that…
Btw, all my questions are intended to understand better, not to doubt some design !
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The SEOS's vertical directivity doesn't help in this case, as it drops away at a quite high frequency (something like 2800Hz for the SEOS12 if I remember correctly). Both the short height and the narrow angle quickly push the lower control frequency upwards. It seems counterintuitive that narrower control needs the dimension (and length) to grow to keep the same control frequency, but that's the case (see Keele for the formulas, again).
>Btw, all my questions are intended to understand better, not to doubt some design !
no problem, I didn't think otherwise. I only chimed in because I find the topic interesting and would like to see more speakers go in this direction. There are limits to either design.
>Btw, all my questions are intended to understand better, not to doubt some design !
no problem, I didn't think otherwise. I only chimed in because I find the topic interesting and would like to see more speakers go in this direction. There are limits to either design.
Interesting that Tom treated it.
IMD is easy to measure. ARTA supports it. Just use two tones (or more) with a certain distance in frequency. There will be new difference tones visible.
Usually the more ways a speaker has the less IMD it produces. Examples are on Neumann's site. Now I wonder if the Synergy Horn as a multi-way speaker follows that or introduces new IMD caused by the shared horn.
I just don't know.
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