Synergy Horn with AMT

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Hi,

just have seen the all the cool threads about Synergy horns and I am also interessted in building one. But in generall I prefer the sound of an AMT over an compression driver.

What do you think will a Synergy horn also work with an AMT on his back?

I am currently thinking about the following configuration:

- Mundorf AMT29CM1.1-R (working from 1,5khz and above)
- 2x PHL 6,5 Inch - 1752ndu Low-Mid on the Synergy Horns left and right side (working from 200Hz to 1,5khz) in about 10 liters.
- 1x BMS 15 Inch - 15N840 Woofer below the Synergy horn (30Hz to 200Hz) in 75 Liter closed box

Attached are the first quick and dirty scetches. Horn is calculated with BWaslos Synergy Horn spredsheet (90x50). I cust moved the height in the back to the AMT´s diagraph height. Distance from AMT to the middle of the openings will be 5,7 cm, if I will move them a little more away from the edges into the middle of the horn (currently it´s about 6,7cm distance because openings are in the edges), so that 1,5khz crossover (1/4 wavelenght rule) should be possible.

What do you think? Is it worth a try or wont this work?
 

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The problem with crossing higher is the synergy horn rule, that the distance (along the middle of the horn) from high frequency diagraph to the middle of the midbass-opening-windows shouldn´t be higher than 1/4 the wavelenght of the crossover frequency. I have also read that the opening-windows should be if possible in the corners. So to keep the openings (in this case four for each horn see my Pictures in first post) near to a Corners they will be About 5,5 - 6cm away from amt which means an crossover Point of 1,5khz.

I don´t know how important it is to make the openings near the corner. If I could place them in the middle of the horn (see attached Picture) I could bring them up to 3,3cm away from AMT which means possible crossover up to 2,5khz.
So can maybe someone of the Synergy specialist tell me why the openings should be in the corners and which disadavantages I will have when placed in the middle?

If I will go up with the openings in the corners and 1,5khz crossover. What do you think can the AMT29 crossed that low with Maybe LR24?
I have seen measuremts of the AMT29 in german Magazin Hobby hifif and the distortion is very low above 1khz even at 20V. The resonance freqeuncy of the driver is at 1,5khz. So any reason why not cross there, even to consider that it´s horn loaded here?
On the other case I have heard from some people that the other big AMT on the market, the Beyma TPL150H sounds terrible crossed lower than 2khz and this one also have very low distortion at Hobby hif above 1khz. So distortion does not seem to be the only indicator of how deep to cross a Driver.
 

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many thanks! Why do you think they are too big for an Unity horn?
I wanted to use them down to About 200Hz crossed to an 15 Inch Woofer so I thought some additional sd can be good.

Should work fine.
The verison with one openeing in the middle and higher crossover or the one with outer openings and 1,5khz crossover?

I am also thinking About 4x 5 Inch PHL 930 instead of two 6,5 Inch (see attached scetches).
In this case I can have both. I can put openings in the edges and I can move them up to 3,3cm in distance to the AMT. But it´s more costly in the end.
 
Considering the Beyma TPL-150H is well behaved above 2kHz, wouldn't an extension of the Beyma horn such that it accommodate the midrange drivers be a good place to start? Extend to a size per Bwaslo's spreadsheet for the midrange cutoff frequency, had maybe 4x 4" midranges (2 per side of the TPL), down to 30 or 400Hz...bad idea??
 
Synergy Horn is patented by Danley Sound Labs. Better to build Unity horns, patent is expired.

He's showing a "Unity" in the pic., so presumably that's what he meant. ;)


Though moot (in this instance):

Is the "Synergy" really patented? (..reading the "Unity" patent that expired - it reads as if it covered the "Synergy" addition: in other words if there is an additional patent, I'm thinking it's void.) :eek:
 
Sorry but what exactly is the difference between synegy and unity horn?
I mean this one here:
Index of /SynergyCalc



I don´t know how important it is to make the openings near the corner. If I could place them in the middle of the horn (see attached Picture) I could bring them up to 3,3cm away from AMT which means possible crossover up to 2,5khz.
So can maybe someone of the Synergy specialist tell me why the openings should be in the corners and which disadavantages I will have when placed in the middle?

If I will go up with the openings in the corners and 1,5khz crossover. What do you think can the AMT29 crossed that low with Maybe LR24?
I have seen measuremts of the AMT29 in german Magazin Hobby hifif and the distortion is very low above 1khz even at 20V. The resonance freqeuncy of the driver is at 1,5khz. So any reason why not cross there, even to consider that it´s horn loaded here?
On the other case I have heard from some people that the other big AMT on the market, the Beyma TPL150H sounds terrible crossed lower than 2khz and this one also have very low distortion at Hobby hif above 1khz. So distortion does not seem to be the only indicator of how deep to cross a Driver.
Would be cool to get your opinions regarding these two questions.
 
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Considering the Beyma TPL-150H is well behaved above 2kHz, wouldn't an extension of the Beyma horn such that it accommodate the midrange drivers be a good place to start? Extend to a size per Bwaslo's spreadsheet for the midrange cutoff frequency, had maybe 4x 4" midranges (2 per side of the TPL), down to 30 or 400Hz...bad idea??

https://www.beyma.com/speakers/Fichas_Tecnicas/000003065.pdf

I'm note sure I could cope with such narrow vertical dispersion, current speakers are 40 degree nominal and I find myself wanting more like 60 degree in most situations. Thinking aloud would some kind of 3d printed grid turning the horn into a multi-cellular in the vertical plane fix the collapsing vertical directivity?
 
Considering the Beyma TPL-150H is well behaved above 2kHz, wouldn't an extension of the Beyma horn such that it accommodate the midrange drivers be a good place to start? Extend to a size per Bwaslo's spreadsheet for the midrange cutoff frequency, had maybe 4x 4" midranges (2 per side of the TPL), down to 30 or 400Hz...bad idea??


The idea in general is not bad but there are a few reasons I don´t want to do that.


1. I wanted to use the Mundorf instead the Beyma
2. Due to optical reasons the Horn has to mach to the 15 inch woofer size and I also want to build the Horn with MDF same as the complete front of the box to have an common look.

3. I wanted to use 6,5 woofers to cover the complete midrange down to 200Hz. The 6,5 woofers will not fit physically on the smaller TPL Horn.
I don´t think that any 4 inch woofer is able to handle that low without beeing extremely stressed.
 
most important question for me still is if I can put the openings in the middle of the horn or I have to put them in the edges?


This will decide the distance to AMT-diagraphm and then which midwoofer-size I can use and which crossover point I can make.

If you have a 3D printer, I've found that nothing outperforms the mid-range taps that I use. Basically the idea is a loooong ribbon shaped tap. By making the tap extra long, you can make it skinny. And skinny taps screw with the overall response less.

In my Ribbon Unity project, the mid-range taps were perpendicular to the wavefront. In my current project, they're in the corners. Both options have their advantages.

JBL uses parallel mid-range taps in their Vertec speaker.

EAW uses fractal taps in Anya.
 
For what it's worth (maybe not a lot), I was never able to get taps in the corners to work out right. Not that I tried a lot of iterations. But the CoSynes taps weren't in the corners, and worked out pretty well (luck). And when I tried to redo them with taps in corners in a set of REALLY PRETTY wood veneer preserving waveguides that were otherwise similar, the off axis response was horrid. My thought then was that maybe it was because moving the taps to the corners moved them away from each other.
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Both options have their advantages.
Very interessting post! So what hear from you, it´s maybe the best to start with an skinny ribbon shaped tab.
Which advantages and disadvantages do you see between the differnt placement of the tabs?

But the CoSynes taps weren't in the corners, and worked out pretty well (luck). And when I tried to redo them with taps in corners in a set of REALLY PRETTY wood veneer preserving waveguides that were otherwise similar, the off axis response was horrid.
Also very interessting. Do you have an picture of the CoSynes Horn (where the tabs where not in the corners)?
Do you still have measurments of the both version (off axis problems)?
 
Measurements are probably on an old hard drive somewhere, but not readily available. I do have this photo from during construction which sort of shows how the ports look (Patrick has the actual speakers, he could probably provide a better photo).
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The horns are rectangular, and moving the ports into the corners changed them from a square configuration (all the ports the same distance from their neighbors and as close as they could be to center) to rectangular (further apart horizontally). It also changed the paths they took slightly (because each ports were cut into edges of two walls rather than into just a single wall). A complication was that the tweeter used could not go down very low so the midranges had to perform higher in frequency than a lot of syn designs, so mids being close was a pretty important thing.
 

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Another maybe interesting data point (well, not data, more anecdote) is that when I did the first large 3DPrinted waveguide, the midrange ports seemed to be virtually invisible to the tweeter. I could cover them with duct tape with little change to the tweeter response, with the ports not in corners -- they were arranged in a square. The originally placed woofer ports, however, played hell with the tweeter response, even though I wouldn't have expected too much tweeter radiation to reach there. I moved those further out and made them smaller to get that interraction acceptable.
 
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