Search found 54 matches

by KMN
Wed Aug 05, 2020 11:27 pm
Forum: Pro Audio Design
Topic: A Second Order Elliptic Equalizer for Vinyl Mastering
Replies: 59
Views: 65138

Re: A Second Order Elliptic Equalizer for Vinyl Mastering

Sample the difference signal (vertical) pre-filter and the difference post-filter then null the two.
Maybe you could feed this noise signal to some kind of event indicator meter or LED circuit.
by KMN
Tue Aug 04, 2020 12:10 pm
Forum: Pro Audio Design
Topic: Mid Side M-S Matrix Uses No Precision Resistors
Replies: 264
Views: 364851

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

Thank you for your comments, sir!
by KMN
Tue Aug 04, 2020 12:06 pm
Forum: Pro Audio Design
Topic: A Second Order Elliptic Equalizer for Vinyl Mastering
Replies: 59
Views: 65138

Re: A Second Order Elliptic Equalizer for Vinyl Mastering

What I do to listen to what is being mono'd by the EEQ is to feed the left input, dead patch the right channel input, mute the left channel output and monitor the right output. Doing this allows me to hear the deliberately introduced LF crosstalk from L into R. Hmm. I may have to give that a try to...
by KMN
Tue Aug 04, 2020 12:01 pm
Forum: Pro Audio Design
Topic: Mid Side M-S Matrix Uses No Precision Resistors
Replies: 264
Views: 364851

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

It occurred to me that the best way to obtain inverted copies of the input would be to use cross-coupled line receivers. Using cross-coupled inputs, both inverted and non-inverted signals are available with identical phase shifts Yes this is what I have been doing since I have a balanced/differenti...
by KMN
Mon Aug 03, 2020 3:00 pm
Forum: Pro Audio Design
Topic: A Second Order Elliptic Equalizer for Vinyl Mastering
Replies: 59
Views: 65138

Re: A Second Order Elliptic Equalizer for Vinyl Mastering

Wayne, I've been playing with your circuits in LTspice. I believe I have come up with a good way to listen to the information removed. This may be useful for deciding whether the chosen filter roll off point is too low or too high based on musical contents presence within the stripped material or if...
by KMN
Mon Aug 03, 2020 11:52 am
Forum: Pro Audio Design
Topic: Mid Side M-S Matrix Uses No Precision Resistors
Replies: 264
Views: 364851

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

In my case I did not want to sacrifice noise margin (Edit: uh SNR) and so talked myself out of the 1246's in the encode. Also I am coming up against rail voltages and 1240's would have put me over when my designs overload margin is considered. Even with the 1243's my current concept still utilizing ...
by KMN
Mon Aug 03, 2020 10:55 am
Forum: Pro Audio Design
Topic: Mid Side M-S Matrix Uses No Precision Resistors
Replies: 264
Views: 364851

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

perhaps I have overlooked something. What I have done to, encode for example, with the 1243's is: M+ -> +in=L+ -in=R- M- -> +in=L- -in=R+ S+ -> +in=L+ -in=R+ S- -> +in=L- -in=R- Ref pins tied to ground, Sense pins tied to outputs. I found these formulas in a Sound on Sound article Left = (M+S)-3dB R...
by KMN
Mon Aug 03, 2020 1:11 am
Forum: Pro Audio Design
Topic: Mid Side M-S Matrix Uses No Precision Resistors
Replies: 264
Views: 364851

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

Thanks for the tips. Using THAT1243's in both the encode and decode makes the math work perfectly. It makes a differential version of the encode and decode seem really clean and nice. You still gotta buffer the inputs though. And you have to do a single ended conversion for the filtering..... And a ...
by KMN
Sun Aug 02, 2020 1:48 pm
Forum: Pro Audio Design
Topic: Mid Side M-S Matrix Uses No Precision Resistors
Replies: 264
Views: 364851

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

How did you do the decoders with THAT1246's? I've done it before and it requires some tricks since the internal resistors do not have equal value. It added stages so I chose an alternate method Hello Wayne and the forum . Thank you again for hosting this forum where conversations like this can exis...
by KMN
Fri Oct 25, 2019 3:37 pm
Forum: Build
Topic: Flat Balanced Input Moving Coil Phono Preamp Construction Information
Replies: 52
Views: 7561

Re: Flat Balanced Input Moving Coil Phono Preamp Construction Information

Sorry if I missed it. Is there a BOM or a cart or a set up for this?