Cool Rob, kinda mirrors my comparisons......varying results with none of them clearly compelling.
I've made the deciding factor whatever shows the most consistent polars after correction. Iow, which behaves best, post tuning.
Btw, what type measurements were you making? Looks like a transfer function down low, and an RTA up high ????
Nice build!
Is it possible lay hands on Mr Waslo's generous and excellent spreadsheet
//
Thanks TNT !
I see fluid linked you to the speadsheet.
I realized i made a mistake in opening post re the speadsheet inputs.
That input snip was for the prototype i was using to get to syn8.
For syn8, I had to expand the size of the prototype a little to increase the bass-reflex port duct length.
The correct inputs and sizes are below.
That's the raw response of the CD (BMS4550) raised 1.5m off the ground at 1m on axis. (no windowing / smoothing applied)
update...
added the secondary flares to syn8..
Still just tacked together with screws and a few brad nails, but i'm about to disassemble it and glue it up, and finish it....
because I REALLY like this one. (just like i did others before
I like its pattern 75x50, better than the prior syn7's 90x60.
About the only thing i don't like better, is the use of two 8" drivers, vs 10"s in the prior.
Bass reflex ports helped get frequency response down to 100Hz, so i guess the only real loss is some extra headbanging SPL capability.
Turns out, i was right about suspecting resonances from the previous syn7's secondary flares, which are foam board wrapped with glass cloth. This guy.
It's not hard to hear in comparison to syn8's wood flares, both sitting on the same subs.
(it's not a matter of sub cabinet vibration effecting the synergies...it's airborn bass waves resonating the foamboard flares.)
Which is a real bummer....had great hopes for the light weight foamboard....but I'll only use the syn7 without the flares anymore.
added the secondary flares to syn8..
Still just tacked together with screws and a few brad nails, but i'm about to disassemble it and glue it up, and finish it....
because I REALLY like this one. (just like i did others before
I like its pattern 75x50, better than the prior syn7's 90x60.
About the only thing i don't like better, is the use of two 8" drivers, vs 10"s in the prior.
Bass reflex ports helped get frequency response down to 100Hz, so i guess the only real loss is some extra headbanging SPL capability.
Turns out, i was right about suspecting resonances from the previous syn7's secondary flares, which are foam board wrapped with glass cloth. This guy.
It's not hard to hear in comparison to syn8's wood flares, both sitting on the same subs.
(it's not a matter of sub cabinet vibration effecting the synergies...it's airborn bass waves resonating the foamboard flares.)
Which is a real bummer....had great hopes for the light weight foamboard....but I'll only use the syn7 without the flares anymore.
Thanks !
The new one, 75x50, has a mouth of 44"x29.5"
The old one, 90x60, is 47.5" x 28.75"
So not too different in size.
One thing i don't understand, is why mouth sizes don't end up with the same aspect ratio, when the pattern ratio is the same.
What i mean is both the 75x50 and 90x60 have a H to V pattern ratio of 1.5x.
But mouth ratio for the 75x50 stays 1.5x, while mouth ratio of the 90x60 moves to 1.6x.
I thought the 1.6x ratio on 9the 0x60 syn7 was due to trying to have the secondary flares incorporate a tractrix curve.
But i see in Synergy Calc, the mouth ratio goes to 1.6x, even for straight-walled secondary's. Clueless why....
Anyway, i do like the H to V look of the new guy better
The new one, 75x50, has a mouth of 44"x29.5"
The old one, 90x60, is 47.5" x 28.75"
So not too different in size.
One thing i don't understand, is why mouth sizes don't end up with the same aspect ratio, when the pattern ratio is the same.
What i mean is both the 75x50 and 90x60 have a H to V pattern ratio of 1.5x.
But mouth ratio for the 75x50 stays 1.5x, while mouth ratio of the 90x60 moves to 1.6x.
I thought the 1.6x ratio on 9the 0x60 syn7 was due to trying to have the secondary flares incorporate a tractrix curve.
But i see in Synergy Calc, the mouth ratio goes to 1.6x, even for straight-walled secondary's. Clueless why....
Anyway, i do like the H to V look of the new guy better
Hi Mark
Thank you for sharing so much experiments, thoughts and results. I find it very inspiring.
I have been warming up to build a Synergy-horn for years, but haven´t had time to concentrate on building things due to other projects. But I like your aproach, as I like the aproach of Chris A. It´s going to be something big, K402-size. Maybe two-way with the AXI2050 driver.
I am going to build for a living-room, 13 feet wide, 26 feet long and 8 feet high. The speakers are going in the corners of the short side.
And now to some questions to your experience:
I would tend to prefure a 75x50 horn over a 90x60 horn with aproximately same Mouth-size. WHAT would you say? The ideer is, to eliminate as much first reflexion as posible.
I am also not going to build for mobility, so I am not so much concerned about wheight. I have contemplated using four 8" drivers, two on each side, with the injectionports in the corners, and the cones centred over the injectionholes. WHAT do you think?
It seems, that you are not bothered by "driversag", as you mount your woofers on top and bottum. Any experience/thoughts there?
Well I hope It´s OK to ask you these questions here in your thread, so that everybody has a chance to learn.
Thank you in advance
Regards from Denmark
Steffen
Thank you for sharing so much experiments, thoughts and results. I find it very inspiring.
I have been warming up to build a Synergy-horn for years, but haven´t had time to concentrate on building things due to other projects. But I like your aproach, as I like the aproach of Chris A. It´s going to be something big, K402-size. Maybe two-way with the AXI2050 driver.
I am going to build for a living-room, 13 feet wide, 26 feet long and 8 feet high. The speakers are going in the corners of the short side.
And now to some questions to your experience:
I would tend to prefure a 75x50 horn over a 90x60 horn with aproximately same Mouth-size. WHAT would you say? The ideer is, to eliminate as much first reflexion as posible.
I am also not going to build for mobility, so I am not so much concerned about wheight. I have contemplated using four 8" drivers, two on each side, with the injectionports in the corners, and the cones centred over the injectionholes. WHAT do you think?
It seems, that you are not bothered by "driversag", as you mount your woofers on top and bottum. Any experience/thoughts there?
Well I hope It´s OK to ask you these questions here in your thread, so that everybody has a chance to learn.
Thank you in advance
Regards from Denmark
Steffen
Hi Steffen, you're welcome and thanks for the kind words.
Chris A's K402 project was the inspiration behind my Syn7 version, the black one.
I tried to copy a tractrix like secondary flare, like a guy name Oohms did (pretty sure that's referenced in my syn7 build thread... let me know if you can't find it.)
I could see the AXI and four 8'' working awesome.
I also like the 75x50 for eliminating first reflections.
Since you don't care about weight, I agree with your plan to put the ports in the corners. Closer to throat the better.
I find centering the cones over the injection ports helps smooth and extend response, but i haven't really seen others report the same. Maybe because most other designs need the ports closer to throat than centering allows.
(Not having the advantage of a CD that can reach to 500Hz or below)
In the same vein re weight, you might want to even consider a 60x40, which will be a little heavier and deeper still, if it has the same size mouth as a 75x50.
I think the 60x40 is my favorite pattern....but that seems to run counter to most folks who like a bit wider i think.
Personally, I'm not at all concerned about driver sag for anything other than sub sized drivers. I've only seen one technical analysis (which i can't find or I'd link it), but it read like it is seldom a real problem. That said, i do rotate my horizontally lying 18n862 drivers in my PPSL subs annually.
Hope this helps !
Chris A's K402 project was the inspiration behind my Syn7 version, the black one.
I tried to copy a tractrix like secondary flare, like a guy name Oohms did (pretty sure that's referenced in my syn7 build thread... let me know if you can't find it.)
I could see the AXI and four 8'' working awesome.
I also like the 75x50 for eliminating first reflections.
Since you don't care about weight, I agree with your plan to put the ports in the corners. Closer to throat the better.
I find centering the cones over the injection ports helps smooth and extend response, but i haven't really seen others report the same. Maybe because most other designs need the ports closer to throat than centering allows.
(Not having the advantage of a CD that can reach to 500Hz or below)
In the same vein re weight, you might want to even consider a 60x40, which will be a little heavier and deeper still, if it has the same size mouth as a 75x50.
I think the 60x40 is my favorite pattern....but that seems to run counter to most folks who like a bit wider i think.
Personally, I'm not at all concerned about driver sag for anything other than sub sized drivers. I've only seen one technical analysis (which i can't find or I'd link it), but it read like it is seldom a real problem. That said, i do rotate my horizontally lying 18n862 drivers in my PPSL subs annually.
Hope this helps !
Hi Juhazi, thanks.
I've kinda learned not to trust nearfield measurements of synergies.
They can look a little too good, and differ from moving back a bit.
And not because of room reflections.....not sure why really...
(By nearfield i mean a distance within 2-3x longest mouth dimension.)
Here's an on-axis meas off the back of my deck at about 3m, early the other morning.
Had some low end boat noise in the background, as evidenced by red coherence trace. Polars of course won't look so good, but they are fine, and still under development when outdoor measurement conditions exist.
I've kinda learned not to trust nearfield measurements of synergies.
They can look a little too good, and differ from moving back a bit.
And not because of room reflections.....not sure why really...
(By nearfield i mean a distance within 2-3x longest mouth dimension.)
Here's an on-axis meas off the back of my deck at about 3m, early the other morning.
Had some low end boat noise in the background, as evidenced by red coherence trace. Polars of course won't look so good, but they are fine, and still under development when outdoor measurement conditions exist.
Attachments
Hi Mark
Thanks for the answers, nice to comunicate with people whith tha same kind of passion.
I am right now reeding "Loudspeakers for Music Recording and Reproduction" by Philip Newall and Keith Holland. Wery aducational, lots of engineering experience.
On page 283 they are discussing cone-shapes. From what I reed there, it makes perfect sense, NOT to have the injektion-holes placed at the edge of the cone, because it is not nesseserily behaving like a piston there. Its simply asymetric! So your aproach with centering the cone over the hole is logical.
John Sheerin on his webside has done some unity-builds, where he has distributed the four midranges in a different way. Only one hole in each hornwall (I think his horn was quadratic) and in the corner. and then the midrange was placed centered over the injection-hole. Words!!!! Can´t really explain! I have tried to find the picture, but could not open it.
I have been wondering why you need reflex-ports? Is it due to almost half membrane-area from 10" to 8" wooffers? Or is it due to smaller injection-ports, because nearer to the throat? I am personally suspicius of reflexports in regards to fase and resonances and transient-behavior!? But then again, you use FIR-filters. Maybe that solves some issues?
Steffen
Thanks for the answers, nice to comunicate with people whith tha same kind of passion.
I am right now reeding "Loudspeakers for Music Recording and Reproduction" by Philip Newall and Keith Holland. Wery aducational, lots of engineering experience.
On page 283 they are discussing cone-shapes. From what I reed there, it makes perfect sense, NOT to have the injektion-holes placed at the edge of the cone, because it is not nesseserily behaving like a piston there. Its simply asymetric! So your aproach with centering the cone over the hole is logical.
John Sheerin on his webside has done some unity-builds, where he has distributed the four midranges in a different way. Only one hole in each hornwall (I think his horn was quadratic) and in the corner. and then the midrange was placed centered over the injection-hole. Words!!!! Can´t really explain! I have tried to find the picture, but could not open it.
I have been wondering why you need reflex-ports? Is it due to almost half membrane-area from 10" to 8" wooffers? Or is it due to smaller injection-ports, because nearer to the throat? I am personally suspicius of reflexports in regards to fase and resonances and transient-behavior!? But then again, you use FIR-filters. Maybe that solves some issues?
Steffen
Hi again
How do you choose your woofers? I´ve noticed, that the most woofers in your builds have a fairly low Qes and corresponding low Qts. What T/S-parameters do you go for?
From your thread on the difference of 10" woofers in the syn7 (neo vs ferrit), it seems that magnet-power Qes is important.
It also seemed to be important, how the membane is constructed, whether it can tollerate compression 1:10 ,stiffness I guess. How do you judge that from specs? Do you consult somebody?
Is the construction of the suspension also something that you look for?
Well, just trying to learn.
Regards
Steffen
How do you choose your woofers? I´ve noticed, that the most woofers in your builds have a fairly low Qes and corresponding low Qts. What T/S-parameters do you go for?
From your thread on the difference of 10" woofers in the syn7 (neo vs ferrit), it seems that magnet-power Qes is important.
It also seemed to be important, how the membane is constructed, whether it can tollerate compression 1:10 ,stiffness I guess. How do you judge that from specs? Do you consult somebody?
Is the construction of the suspension also something that you look for?
Well, just trying to learn.
Regards
Steffen
Room pseudoanechoic measurement looks very good! Synergy should have extremely smooth directivity anyway.
I was wondering how port tuning works IRL. Ports I've never seen in synergys earlier... They might leak midrange sound as well, there's gradual phase rotation 180deg... Ports are opening so close to the edge, horn effect is minimal? But these issues are very difficult to measure!
I was wondering how port tuning works IRL. Ports I've never seen in synergys earlier... They might leak midrange sound as well, there's gradual phase rotation 180deg... Ports are opening so close to the edge, horn effect is minimal? But these issues are very difficult to measure!
Hi Steffen, sorry i forgot to reply to this earlier.
Thanks for passing on what you are reading about port locations under the cone.
I centered them based on a simple closed test box that allowed me to measure response as i moved a plate with a port or ports around, over the cone.
A single circular port centered kept winning, both in terms of response smoothness and better frequency extension, particularly on the high end.
I guess the tradeoff in a synergy horn is maybe mucking with the horn outflow more so than when ports are in the corners, but i can't say i've seen that happen. As far as i can tell, mouth termination seems to muck things up much more than port location.
I think i can picture what you're saying John Sheerin did...always love reading his work.
The reflex ports on the 8" were needed to boost low end response. My understanding is they have no horn loading whatsoever that close to the mouth and act as any normal reflex port.
I tried putting them in closer to the throat, but surprisingly it really messed up response. They are 5.4cm in dia. They and the ducts that feed them are simply the product of trial and error measurements.
Hi again
How do you choose your woofers? I´ve noticed, that the most woofers in your builds have a fairly low Qes and corresponding low Qts. What T/S-parameters do you go for?
From your thread on the difference of 10" woofers in the syn7 (neo vs ferrit), it seems that magnet-power Qes is important.
It also seemed to be important, how the membane is constructed, whether it can tollerate compression 1:10 ,stiffness I guess. How do you judge that from specs? Do you consult somebody?
Is the construction of the suspension also something that you look for?
Well, just trying to learn.
Regards
Steffen
Hi again back !
My woofer choice is not too sophisticated...i have to admit i don't pay much attention to T/S parameters.
I look at sensitivity, AES power handing, xmax, and a published response curve that looks like it will be possible to get response down to 100Hz without too much boost.
Then the one T/S i use as a tie breaker is BL...i really like high BL !! Particularly for 10:1 compression.
As far as membrane stiffness, on the various sub and mid drivers i've purchased and compared, stiffness seems to correlate highly with BL.
I kinda figure rightly or wrongly, strong motor implies strong cones.
No clue about judging suspensions, other than on subs where double spiders seem good to have.
I take it you're talking about the reflex ports and not the main port down in the throat.
Yeah, no horn loading at all. The duct area and length that feeds them, works just like any other reflex-port. I've read this is true for the DSL synergies using reflex ports too.
Measurements to find the reflex port size and duct dimensions were simply watching the response curve change as a i played with different port locations, sizes, and ducts.
I really didn't want to add them, but i couldn't get the response of the 8"s down low enough to mate with my standard sub xover usage at 100Hz.
That said, the build design with the cones on top and bottom and inside the side walls, makes it super easy to add the ports in the resulting cavity. And helps with bracing too.
I'm counting them a big win.
Hi Mark
Thank you for answering. I still have a kitchen to finish and a carport/garage to build in spring. But I am so "obsessed" with the consept of synergy/MEH, that I will build something big sometime soon.
I have been listening to fullrange-speakers (Visaton B200 and Coral Flat 5) for a long time, and am somehow used to "pointsource" and "simple" fase-curve (ie no crossower), but I want more frequency-range and SPL. Chris A once told me, that a MEH can come close to fullrange-sound if done right.
I contemplate to use Acourate by AudioVero. It´s a FIR toolset for crosowers, driver-linearisation, targetcurve, roomcorrecten, all kinds of measurment........ Mitch Barnett has written a book about the software.
By the way. What amplifiers do you use with your Coax-compressiondrivers? I have 6 MiniDSP plate-amps with ICEPOWER and DSP, that I will try to use, but am a bit worried about the high efficiency of an AXI 2050 and the ICEPOWER amps. We´ll see. I´ll maybe go for something class A?
Steffen
Thank you for answering. I still have a kitchen to finish and a carport/garage to build in spring. But I am so "obsessed" with the consept of synergy/MEH, that I will build something big sometime soon.
I have been listening to fullrange-speakers (Visaton B200 and Coral Flat 5) for a long time, and am somehow used to "pointsource" and "simple" fase-curve (ie no crossower), but I want more frequency-range and SPL. Chris A once told me, that a MEH can come close to fullrange-sound if done right.
I contemplate to use Acourate by AudioVero. It´s a FIR toolset for crosowers, driver-linearisation, targetcurve, roomcorrecten, all kinds of measurment........ Mitch Barnett has written a book about the software.
By the way. What amplifiers do you use with your Coax-compressiondrivers? I have 6 MiniDSP plate-amps with ICEPOWER and DSP, that I will try to use, but am a bit worried about the high efficiency of an AXI 2050 and the ICEPOWER amps. We´ll see. I´ll maybe go for something class A?
Steffen
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