Midrange test data

The following midranges were tested--

Accuton C44

Dayton RS52

Morel MDT55

Scan Speak 12M4631G

NOTE--For all these tests, my MM2 preamp was not used. This means that the levels are NOT calibrated to any reference. Within this group, SPL comparisons are valid, but cannot be exactly compared with any other test data not on this page. Roughly speaking, the amp has 6-7dB of gain. For the linear tests, add 15-16 dB to get 1m sensitivity. For the nonlinear tests, 100dB spl at 0.25 m is roughly equal to 94dB at 1m. (100-12dB going from 0.25 to 1m, then adding back the 6dB of gain lost by not using the preamp.)

The following data are shown

Impedance

Frequency response at 1 meter-Note the SS12M was done open baffle and chambered.

Nonlinear distortion at 0.25m-triplets centered at 400, 800, 1500, 3000 and 5000 Hz. Note also that there are two graphs for the 12M. The first is open baffle and the second is chambered.

Impedance data-Jumbo sized graph.

Frequency response

Note that the SS12M graph above was done open baffle on my standard baffle, described elsewhere. The graph below is a comparison graph of the SS12M open baffle and chambered.

Nonlinear distortion data

At 400 Hz.

Note that I set marker five on the sixth order products (2.4k, instead of 2k).

Chambered SS12M

At 800 Hz

Chambered 12M at 800 Hz

At 1500 Hz

Chambered 12M at 1500 Hz

At 3kHz.

Chambered 12M at 3k

At 5kHz.

Chambered 12M at 5000 Hz.

Conclusion

All of these are good drivers. General comments.

The Accuton C44 and the Dayton RS52 -- Between these, there isn't a clear winner. The C44 has better distortion numbers, but it's very, very close. On the flip side, the sensitivity of the Accuton is low (but the price is not...) and the sensitivity of the Dayton is quite high. The Dayton is more linear in the passband, but some work has to be done to tame the resonant peak. So it's more a "pick 'em" situation.

What about the Morel? Still pretty nice, but doesn't test as well as either the Accuton or the Dayton in tems of low end distortion/excursion. In it's favor, it has the smallest flange, which is very helpful in overall integration to the tweeter.

The 12M shouldn't be included here, since it really is a different beast altogether. It has the best nonlinear distortion at 400 Hz, and the only one I'd use down that low. Interestingly, it does not distinguish itself higher up; probably some more investigation is needed here. (Don't get me wrong. The SS12M is a very impressive mid. I just was a little surprised at the nonlinear numbers, given the extra Sd.) It is extremely well behaved out past 6-7k with a nice, smooth rolloff. This is the driver you cross to a 10-12" woofer. The domes are more suitable to an 8", although, I think with some thought you could pull off a 10" to RS52 or C44.

Current pricing as of 7/9/06 for a PAIR

Accuton C44        $470

Dayton RS52        $68

Morel MDT55      $172

SS 12M 4631G    $438   

As I said, all are very good. Each has its strengths and weaknesses. You can make your own judgement on value, however.

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