MTM with mid domes

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waxx

waxx

Member
Joined 2014
#1
While discussing some possible project that i should design for someone, he asked if i could do an WWMTM with middomes in stead of cone middrivers. I tried to see if there are examples of that, but could not find any.

Is there a reason why this is never done before. Or did a mis some designs on that?

Are there disadvantages on that? Because it looks like this should make it easier to put the mids close enought to each other to work right, even with a relative high crossover point to the tweeter.

We are still in the brainstorm phase, so no decisions on drivers or so yet. It's just an wild id that need a bit tought and check on realism...
 
#4
The trade-offs balance much more towards cone midrange drivers than dome midranges. That's why you don't see them anymore.
John Dunlavy wrote an excellent white-paper on this many years ago. (There are numerous other references.)

If the desire for using dome midranges is some sort of aesthetic thing, I suggest to talk him out of it. 🙂

Dave.
 
#5
Davey said:
The trade-offs balance much more towards cone midrange drivers than dome midranges. That's why you don't see them anymore.
John Dunlavy wrote an excellent white-paper on this many years ago. (There are numerous other references.)

If the desire for using dome midranges is some sort of aesthetic thing, I suggest to talk him out of it. 🙂

Dave.
Click to expand...
He still sells a speaker with middomes, actually a even bigger one than the one we were thinking off, called the Duntech Sovereign. I did not know it.
1667584116375.png

http://duntech.com/products/sovereign.html


I can't find that white paper altough, do you have a link?
 
#6
Based on most domes available to DIY today, the biggest cons are definitely cost, and the diminished return of extending the radiating area of mid domes which have limited usable bandpass ranges in the low end. The easier thing may be go to 4 way for a bigger bass driver and to get the most out of the single filler dome instead of doubling up on them.
 
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#8
waxx said:
While discussing some possible project that i should design for someone, he asked if i could do an WWMTM with middomes in stead of cone middrivers. I tried to see if there are examples of that, but could not find any.

Is there a reason why this is never done before. Or did a mis some designs on that?

Are there disadvantages on that? Because it looks like this should make it easier to put the mids close enought to each other to work right, even with a relative high crossover point to the tweeter.

We are still in the brainstorm phase, so no decisions on drivers or so yet. It's just an wild id that need a bit tought and check on realism...
Click to expand...
Have done this two times. With dayton domes, or philips. In both cases mtm, in both cases ended up with exceptionaly good sounding speakers.
 
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#9
Joe D'Appolito invented MTM Design due to the fact that midrange drivers had low power capabilites at that former times, and so to increase maximum sound pressure capabilities by doubling cone area - without spreading sound sources too much for limited living room listening distance and without narrowing horizontal dispersion too much, which will occur with larger drivers. He also formulated design constrains to minimize the significant drawbacks, which occur especially to vertical dispersion (BW filters, xover frequency vs. driver distance) and are hard or impossible to reach with usual cone + dome drivers. So in almost all designs these criterias are not met; some (not me) like the special sound of narrow dispersion & comb filtering in a certain frequency range, what may have advantage in some bright rooms with lots of floor and ceiling reflections. Large dome mids like e.g. from Volt and ATC have very, very high power capability due to their large voicecoils and very robust suspensions and are often the least limiting drivers in a system, even if combined with high power 15" woofers. They also don't allow tight positioning demanded by D'Appolitos criteria due to their very large magnet systems. So I see no need, just drawbacks to implement that...
 
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#16
#17
First of all, thanks for al the info given.

The speaker is not for me, but for an old friend that is very rich. He wants to replace a pair of way to expensive wilson's with it. He does not like them at all and sold them. He heared some diy speakers that had a Bliesma middome (not mine) and heared much of what i did build, and came with this and a huge budget to do it right to me. He trust me more on this than any salesman or commercial company as i fixed a lot of his snake oil problems and set most of his systems right for way less money than what was there before i started to change it.

His id was to use Bliesma tweeters and mids, and the purifi 8" woofers. Crossover would have to be passive as he wants to use it with the Passlabs amp that is now driving the wilsons. I already studied it and came with a predesign that should work with those drivers with 3th order crossovers at 800 and 2000Hz. But i just wanted to double check if I missed something (I'm just a very enthousiastic amateur, i certainly don't know it all...)

Altough he is a bussiness man running several companies at the same time, his hobby is wood furniture building, and he got a wood workshop where most of use only can dream of, and he knows how to use it. He also knows how to solder and basic electronics. He just needs me for the design part and to avoid snake oil stuff like he had to much in the past but the building will be him mostly.

I'll go further with it i think. It may be interesting to do. If i'm allowed by him (he pays me), i'll post info about it.
 
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#18
planet10 said:
Wrong link format is incorrect. It is the right URL but translates to what you need given your chosen posts per page. Anyone with a different post setting will not get them where you intend (ie me). Copy the URL embedded in the post # not the translated one from your browser bar.

dave
Click to expand...
Ok dave, thanks, i understand. Was using phone and just copied browser.
Here are pictures just for fun.
 

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