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Magnepan 20R vs 20.1Rs

Anyone know the difference between the Magnepan 20Rs and the current 20.1R version. I am pretty sure they both have the push pull quasi ribbon midrange (verses the 3.6s'midrange type panel) but I am not sure how the base panels compare. The 20.1 is a push pull diplanar bass driver. What is the bass in the earlier 20R? Anyone heard a side by side comparison. I tried to find earlier threads but with no results.
bbro

Showing 4 responses by josh358

josh358
286 posts
 
That's interesting. Maybe you're measuring interference between the holes? There's also going to be some lobing at the crossover point. I haven't heard the effect either, maybe it's just because the brain is accustomed to comb filter effects at the highest frequencies. Anyway, it's the ear that counts. I tried the experiment you mentioned, flipping them around, but didn't think to measure them.
josh358
286 posts
 
Bbro, do a search for HP's Absolute Sound review of the 20.1, it's available online and he compares the two versions.

Hi Magfan, they said in a review at the time (of the 3.3? whenever they flipped it) that they flipped the pole piece to the back to get better high frequency response. JBen did some measurements of the MMG's from both sides, and with the MMG's anyway there's a bit of a peak above 10 kHz followed by rolloff from above 15 kHz from the pole piece side. But I think it's a matter of preference, with my MMG's anyway I think the imaging is better from the pole piece side, but that the top octave is better from the front.
josh358
286 posts
 
IIRC, the Radio Shack meter goes all the way up, but it's not even roughly accurate towards the top. So you could see relative changes but not absolute ones. If you do a search on the Planar Asylum, you should be able to find JBen's measurements of his MMG's with mylar front and mylar back. They're close enough to the 1.6's that I suspect the results would be similar.

I actually liked them both ways. On balance, I preferred front, because getting the high end right was more important than the better imaging from the back, but I can see that that could depend on personal preferences and your room (mine was very live when I tried it, no furnishings at all).
josh358
286 posts
 
I suspect that the top end of the Radio Shack meters (and most inexpensive calibrated mics) is too inconsistent. If you want to make inexpensive measurements that are more meaningful, you might look into a calibrated Behringer:

http://cross-spectrum.com/measurement/calibrated_behringer.html

Parts Express is selling what looks to be the same thing with a cal file for only $40!

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=390-801
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