I have read the dozens of posts in this thread related to the MD60N, and I find myself a bit puzzled by the disappointment and criticism. 95 dB sensitivity, usable range from 800 to 6k, low distortion at high SPL. If you need this kind of driver, this unit is a definitely worth considering, and there are not very many competitors for it.
...and no, it is not an ATC SM75, nor is it a Volt VM752. If it were equal to those drivers it would be $400.
...and no, it is not an ATC SM75, nor is it a Volt VM752. If it were equal to those drivers it would be $400.
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I wouldn't use it above 3kHz. It suffers the same problem that every other dome does - the faceplate is still 130mm like a 5" cone mid so even if you use a tiny tweeter of 30mm dia the best case CTC is about 80mm.
At 80mm CTC and crossed at 6kHz, a deep null occurs between mid and tweeter at just 20 degrees off axis. If you drop the crossover to 3kHz, it takes 45 degrees off axis to cause a null. I think that is even a bit lousy so I'd cross at 2.5kHz which pushes the null to about 60degrees off axis.
To completely avoid nulls you find yourself having to cross the dome mid and tweeter at <2kHz and the bandwidth of the dome mid becomes so small (barely 1 octave) that you start to question why you even bothered and don't just cross a 5-6" cone midwoofer straight to the tweeter.
A 2-3" dome mid is best used to bridge the gap between a 6-8" woofer (or two!) that doesn't want to play above ~600-900Hz and a 1" tweeter that doesn't want to play below ~2-3kHz.
There are 4-5" cone mids that will go lower than a dome and up to 3kHz cleanly, but not at 90-95dB sensitivity like a dome will. There's no free lunch
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Some drivers have a very broad applicability, like a 6.5 inch midwoofer... it can be used everywhere.
Other drivers have a more limited application... like an AMT tweeter, or a 15" subwoofer. These kinds of drivers have just one application, and if you don't need them, they don't seem to serve a purpose.
And that is exactly the application. This driver will cleanly cover two octaves ( 800 - 3200 Hz) at 95 dB/2.83V sensitivity. This is right where a lot of 8 inch drivers start to misbehave. It is a niche product, but an important niche.
Other drivers have a more limited application... like an AMT tweeter, or a 15" subwoofer. These kinds of drivers have just one application, and if you don't need them, they don't seem to serve a purpose.
And that is exactly the application. This driver will cleanly cover two octaves ( 800 - 3200 Hz) at 95 dB/2.83V sensitivity. This is right where a lot of 8 inch drivers start to misbehave. It is a niche product, but an important niche.
No complain about this unit, I just happened to to find this unit while I was looking for an alternative to ATC or horn to match 15" woofers. (ATC is unobtainable)
I do not want to see a crossover point or two between 500 and 4K, the most sensitive area, and it seems there aren't many choices. FR alike units (SS 10F) look great, and they should sound great, while they are a little low sensitivity. Someone said before, but I also wish if SB would make SM75 variant in the future. Would be a great unit.
I do not want to see a crossover point or two between 500 and 4K, the most sensitive area, and it seems there aren't many choices. FR alike units (SS 10F) look great, and they should sound great, while they are a little low sensitivity. Someone said before, but I also wish if SB would make SM75 variant in the future. Would be a great unit.
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Agreed the SS10F is a remarkable driver & more useful as a really wide-band mid than any dome. You might try horn-loading it for higher efficiency, lower distortion and lower the xover frequency: J.Crowe Sabourin horn Joseph Crowe sells plans for this horn for just CA$15. Meant for 4" Fostex FE108EZ, which seems a bit bigger, but should work -- and probably can be scaled down if desired. (JC will customize plans, too.)
Due to the size of the flange I think even going as high as 3kHz is pushing it. I would want to cross it lower.
There's no denying that it fits the application as a filler, but this is just the same as every other available mid-dome out there. All of them can do 800Hz to 3kHz with varying sensitivity and price points. SB chose to follow the crowd instead of make a stand-out product. All other mid-domes are 2", SB went with a 2.5" and used that extra SD to increase product sensitivity rather than greater extension down low. Sensitivity aside the biggest issue is that it only has 0.5mm of xmax. Even if they'd optimised the driver for 89dB sensitivity, and extension down to 400Hz, with only 0.5mm of xmax it would be very SPL limited down there.
It has been said that maintaining linearity with large domes, at large excursion, it problematic. There's a reason why ATC/Volt use spiders in their drivers. The TB unit didn't have spiders but I had read that rocking could be an issue with it. Maybe so, maybe not. Maybe tolerances need to be just right for stable operation without a spider and over time problems could develop.
If consistent operation, with spiderless domes, at appreciable xmax is something of a design challenge perhaps there is a very good reason why we don't see anyone releasing an ATC/Volt killer. To do it properly would be considerably more involved than simply enlarging a tweeter.
Hi HiFiCompass,
If you have the possibility to test one of the Kartesian Acoustic drivers,
that would be great.
Check out their Mid120_vHE, 5" 8ohm 91db and very linear
or Wom165_vMS, 6.5" 8ohm 90db
Most of their drivers use a hybrid cone material made of carbon and glass fibers,
that is 10 times more rigid than conventional carbon fibre.
Their drivers are available through TLHP
Regards,
Danny
If you have the possibility to test one of the Kartesian Acoustic drivers,
that would be great.
Check out their Mid120_vHE, 5" 8ohm 91db and very linear
or Wom165_vMS, 6.5" 8ohm 90db
Most of their drivers use a hybrid cone material made of carbon and glass fibers,
that is 10 times more rigid than conventional carbon fibre.
Their drivers are available through TLHP
Regards,
Danny
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