SNR-1 : Mundorf / Scanspeak 2 Way

Hello everyone,

I'd like to offer all of you this Christmas present. The design data for the SNR-1.
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The cabinetry is by Lee Taylor of Taylor Acoustics. Drivers:


  • Mundorf AMT25CM1.1-R

  • ScanSpeak Revelator 18W/4531-G00
I can guarantee I screwed up the bass measurements. I got busy and never got back to splicing together the port and driver correctly. Take it with a grain of salt. The cabinet volume is straight up what Madisound recommends:


1.0 cubic foot box with 2" vent by 5" long for F3 of 40Hz


In terms of sound quality, I really love the final result. It needs a LOT of vertical space or damping though, you don't get nearly enough transparency out of them if they are cramped. They may seem a little lean to many, as they do not thump at all, but on movies, classical and classical they are pretty amazing, but may lack a smidgen along the lower registers of a double bass and piano. It's hard to tell where I am due to bad listening situation. There's no hype in the sound. They do not exaggerate presence, treble or bass. They sound amazing on heavy bass like the opening of the Universal Pictures credits, but like I say, not going to give you a Rock n Roll punch either. I suspect you could tune the woofer crossover somewhat and increase the tweeter damping to get this if you wanted, at the cost of some sensitivity.

The measurements above about 800 Hz were done at 1m, but I did attempt to splice in close-mic data for the woofer. In general it is very close to what I have measured in the far field.



Enjoy!




Erik
 

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Hey Bill, I'd suggest you grab the XSim files I included. I've been having this argument with Steve, who doesn't have them to measure or he'd get off his soap box. The actual drivers are far better measuring than the spec sheets, so no, it's not a big deal. In fact, the notch filter I include is practically optional.

Honestly the FR is MUCH better than the spec sheet, so my guess is SS at some point improved the drivers without improving the spec sheets. While I worry about the balance, and whether others will like it the way I do what I can state, unequivocally is that the mid-woofer to tweeter transition is absolutely seamless and they simply do not sound like speakers. You can't locate them as separate sound sources, and those who have listened who are not audiophiles describe them as very "warm" sounding. None of that would happen with this simple crossover if those woofers were standing out at all.

Best,

E
 
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Depends exactly how you measure it. :) There's quite a bit of EQ going on in the tweeter, hidden in the 3rd order high pass filter, to bring it down and extend the top octave. The tweet is so sensitive though it can give up a lot and still be efficient. :)

Best to look at the filter response graphs to see what I mean.
 
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The warm or lush sound divides opinion; without wanting to start a s#$tstorm, Troels tried a 2 way with this driver(not sure which ohm rating) and kind of gave up, concluding it was better suited to a 3 way.
But there are plenty of speaker builders who are satisfied with their results using these in a 2 way
 
I`m not sure why he`d have given up, the 18W is among the best mass produced midwoofers for a 2-way. There was a test in Voice coil where when even driven beyond its linear range it did very well. It makes a superb 2-way (with all its limitations) with a shallow waveguide. Perhaps what you mean is the fact this woofer wants a bigger than usual box, so you have ot go for a floorstander anyways and if you do, why not just do a 3-way with a 10" at the bottom :)
 
Oh, I think I know what happened! He's attempting a series crossover! My design is parallel. Unfortunately he seems to be generalizing his inability to make this woofer work in series as a general failure of the woofer, which is not what I found.

But as I have alluded to, my measurements are simply better than the spec, and maybe better than Troels. This may indeed be a driver that has been improved over time without being mentioned.


Best,

E
 
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This woofer does not need a notch filter. I saw his design and what he got there was a diffraction effect, there is a wide wrong belief that a 16-18cm woofer will be too directional and cannot illuminate the edges. While the amplitude will not be as high as if it was a small radiator, it still does and the bump makes some female vocals sound nassal, hence his notch filter. If he did a more careful work to the baffle, this would have been avoided but it also comes down to how feasible it would be - sometimes soldering a lcr trap is much easier, Gravesen used to build these for the diy community so I can understand his drive for simplicity.
 
The 3.9mH/22ohm/10uF notch Troels is using is for the small energy storage peak around 700-800 Hz. This is not centered at 4k, and I don't see any other notch in the system. This blip is common in the Revelator woofers, as the 15W also has it. It makes the vocals come through a bit forced and forward without the notch in place.

Later,
Wolf
 
Sorry, but I used a notch filter at 4khz, it's rather broad, almost too broad to call it a notch, and it helped flatten the woofer's rolloff significantly. Of course, I include my design files, so anyone who wishes to improve upon my crossover is free to do so. :) But I agree with everyone but Troels and Steve: This is a very nice, easy to use mid-woofer.

Interestingly, Troels uses a related 6.5" in another design, calling it the best mid-woofer he ever heard. :) I kind of agree. See here...

Fusion

There's another active thread on it as well:

Troel's new big 3 way classic

( I am being verbose for the sake of posterity).

Best,

E