I'm dipping my toe in nervously here months earlier than I'd prefer - despite weeks of reviewing the impressive volume of threads and data on MEHs, im still only near surface level understanding but here goes anyway. 😆
So yes, wondering on this point myself - Most of the documented PA targeted builds I've researched like the SynTripP or Scott Hinson's build seem to favour expensive coaxials like the DCX-484 or at least a fairly no-nonsense 1.4 like the CDX14-3050 or a HF1440. Is there an example of someone knocking out a MEH using a more budget friendly 1 inch CD like a DE250 that could maybe match the output of say a decent 12 inch plus Horn BR top box above 100 Hz ?
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This is a great thread and I don't disagree with anything in it. I can even second some of it base on my own experience with a 28" wide corner synergy about 8 years ago. I simply no longer have room for such large speakers. What I am investigating instead is using cardioid to extend the pattern control of smaller driver/waveguides/coax to get most of the advantages of synergy with less effort, perhaps at some sacrifice of top end smoothness.
What I have in ABEC+ Vituix simulation now is very much like a D&D 8C clone, except the waveguided tweeter has been replaced with a Radian 5208C 8" coax. The 8" coax is supported by an 8" woofer directly below it, and a 10" subwoofer in the rear. Attached below is its simulated horizontal polar map. This pattern control from a bookshelf on steroids sized structure only 268 mm wide.
I'm not a typical DIYer so much as an engineer that likes to simulate until I have something that I'm pretty sure is going to work, at which point I have the pieces CNCed and glue them together. If I were more into experimentation and 3D printing, I would likely be developing a small synergy with 4 4NDF34 mids with backs open to cabinet slots to replace the 8" coax. I think this could be better than a coax but I don't have appetite at this time for the type of work needed to bring it to fruition. Of course, even with simulation, one can't avoid the experimentation stage in optimizing the absorption for cardioid.
What I am suggesting is that if you can't go big, don't just envy those who can, go cardioid. There is some cost in headroom but depending on how loud you listen, that might not matter. That is what I always wonder about and can't address in simulation - how much SPL/headroom is enough?
What I have in ABEC+ Vituix simulation now is very much like a D&D 8C clone, except the waveguided tweeter has been replaced with a Radian 5208C 8" coax. The 8" coax is supported by an 8" woofer directly below it, and a 10" subwoofer in the rear. Attached below is its simulated horizontal polar map. This pattern control from a bookshelf on steroids sized structure only 268 mm wide.
I'm not a typical DIYer so much as an engineer that likes to simulate until I have something that I'm pretty sure is going to work, at which point I have the pieces CNCed and glue them together. If I were more into experimentation and 3D printing, I would likely be developing a small synergy with 4 4NDF34 mids with backs open to cabinet slots to replace the 8" coax. I think this could be better than a coax but I don't have appetite at this time for the type of work needed to bring it to fruition. Of course, even with simulation, one can't avoid the experimentation stage in optimizing the absorption for cardioid.
What I am suggesting is that if you can't go big, don't just envy those who can, go cardioid. There is some cost in headroom but depending on how loud you listen, that might not matter. That is what I always wonder about and can't address in simulation - how much SPL/headroom is enough?
How much SPL is enough? That depends on your average listening levels, and type of content. I feel that a good 20-30 dB of headroom is enough for most recordings.
If you like to play some of the Danley recordings at spirited levels, you quickly find out how much power is required. They will gobble up all of the headroom you thought you had.
If you like to play some of the Danley recordings at spirited levels, you quickly find out how much power is required. They will gobble up all of the headroom you thought you had.
This week I’m going to listen to a pair TAD 4001 with original Be, that is quite rare in my country.
But yesterday I found a second interesting option, the M1 driver from Lamar Audio with a carbon voicecoil which can cover from 50hz to 5Khz -3db.
The throat of this driver is only 0.7inch.
I was wondering if you can use this driver in a ‘synergy horn’ design and adding a supertweeter..?
Crossover point at 4Khz will mean it tap hole has to be in 21mm from the apex.. So perhaps creating some sort of dual throat idea?
Do you guys think this could work? Meaning I can place the drivers and get good phase response and time alignment?
But yesterday I found a second interesting option, the M1 driver from Lamar Audio with a carbon voicecoil which can cover from 50hz to 5Khz -3db.
The throat of this driver is only 0.7inch.
I was wondering if you can use this driver in a ‘synergy horn’ design and adding a supertweeter..?
Crossover point at 4Khz will mean it tap hole has to be in 21mm from the apex.. So perhaps creating some sort of dual throat idea?
Do you guys think this could work? Meaning I can place the drivers and get good phase response and time alignment?
The reason that dual-diaphragm compression drivers (ring radiator type) exist is to address this problem.
Why don't you look at using one of those, instead?
Chris
@Cask05
I think of three benefits: (but correct me if my idea is not gonna work.)
1. The main reason that I like to use one driver for the vocal area / and the most important range the midrange. Meaning no crossover is needed at around 5- to 600hz.
2. This means the LF woofers come in from 100 or 80hz down to 30hz or lower. I can by amp these with Hypex DSP plate amp.
3. Although TAD is considered king of compression drivers a good supertweeter is hard to beat. By choosing the Lamar driver I can add a nice 1” Be supertweeter or another super tweeter solution.
But I’m not sure if the Lamar driver and a supertweeter can be implemented in a synergy horn and correctly sum up and having flat phase response.
I think of three benefits: (but correct me if my idea is not gonna work.)
1. The main reason that I like to use one driver for the vocal area / and the most important range the midrange. Meaning no crossover is needed at around 5- to 600hz.
2. This means the LF woofers come in from 100 or 80hz down to 30hz or lower. I can by amp these with Hypex DSP plate amp.
3. Although TAD is considered king of compression drivers a good supertweeter is hard to beat. By choosing the Lamar driver I can add a nice 1” Be supertweeter or another super tweeter solution.
But I’m not sure if the Lamar driver and a supertweeter can be implemented in a synergy horn and correctly sum up and having flat phase response.
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Do you know what constant directivity horn they used for this measurement?
Do you think the M1 needs a way longer throat like a WE snail horn?
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They used a pwt not a CD waveguide for the measurement. A CD waveguide offers almost no loading at low frequencies.
Yeah, needs to be really big for what you get and with this one apparently needing a full size ~45 Hz/1" throat = ~34400/45 = 765 cm/301" long with a mouth perimeter = ~these dims if suspended in 4pi space like a mids normally would be........