Search found 5 matches

by eweitzman
Mon Feb 27, 2012 4:41 pm
Forum: Pro Audio Design
Topic: Mid Side M-S Matrix Uses No Precision Resistors
Replies: 264
Views: 496874

Re: Mid Side M-S Matrix Uses No Precision Resistors

While the ideas were still simmering in my cranium, I recorded a bit of a warped LP and looked at the signal in Audition. Also did some mid/side processing and filtering like the circuit, and also used low pass filters to keep the out of phase stuff only. It's amazing how much was there and though s...
by eweitzman
Mon Feb 27, 2012 3:40 pm
Forum: Pro Audio Design
Topic: Mid Side M-S Matrix Uses No Precision Resistors
Replies: 264
Views: 496874

Re: Mid Side M-S Matrix Uses No Precision Resistors

I wanted to check back in and see how this is working out. I wrapped up my phono preamp project this weekend. Yippee! Regarding the rumble filter, I removed the 100R buildout resistors from both the phono preamp outputs (where they could muck up the input THAT1240 resistor precision) and the rumble...
by eweitzman
Mon Jan 16, 2012 3:43 pm
Forum: Pro Audio Design
Topic: Mid Side M-S Matrix Uses No Precision Resistors
Replies: 264
Views: 496874

Re: Mid Side M-S Matrix Uses No Precision Resistors

When you reduce (filter) S, you are getting rid of the difference between L & R. So the large xtalk with your 100Hz S filter is precisely what I'd expect. I don't understand why removing the difference signal would show up as crosstalk. Would you mind explaining that? I guess it has to show up some...
by eweitzman
Mon Jan 16, 2012 3:41 pm
Forum: Pro Audio Design
Topic: Mid Side M-S Matrix Uses No Precision Resistors
Replies: 264
Views: 496874

Re: Mid Side M-S Matrix Uses No Precision Resistors

Lots to think about. Thanks. The 20Hz filters are *not* precisely matched. The decoder is done as shown in this post, except that a LM4562 is used for the inverter instead of another THAT1240. http://www.proaudiodesignforum.com/forum/php/viewtopic.php?f=6&t=112&start=120#p2127 The driving source is ...
by eweitzman
Sat Jan 14, 2012 3:13 pm
Forum: Pro Audio Design
Topic: Mid Side M-S Matrix Uses No Precision Resistors
Replies: 264
Views: 496874

LP rumble filter crosstalk

Thanks for this clever circuit! I used it to build an LP rumble filter for my phono preamp. It has separate HP filters in the mid and side channel to take advantage of the fact that bass is converted to mono below some frequency (70Hz, 100Hz, 140Hz, 200Hz, depends on production) before the lacquer i...