Search found 56 matches

by KMN
Thu Aug 27, 2020 4:42 pm
Forum: Pro Audio Design
Topic: A Second Order Elliptic Equalizer for Vinyl Mastering
Replies: 64
Views: 69467

Re: A Second Order Elliptic Equalizer for Vinyl Mastering

I did listen to the warp (without my shim to make it worse) and it has harmonics that are in-band which sound a little like surface noise. Sounds kinda like a "whump" along with a LF "crackle" which are rotationally-related. On this particular disc it was once per revolution. Nice! This is where th...
by KMN
Thu Aug 27, 2020 1:52 pm
Forum: Pro Audio Design
Topic: A Second Order Elliptic Equalizer for Vinyl Mastering
Replies: 64
Views: 69467

Re: A Second Order Elliptic Equalizer for Vinyl Mastering

That's pretty cool, man. After our last conversation, I have wondered, since much of it is undoubtedly subsonic, maybe a good way to use this signal is sending it to a spectral display. Not too many preamp/ADC combos would be able to capture frequencies of interest, probably. but I modded my Flat Ph...
by KMN
Wed Aug 05, 2020 11:27 pm
Forum: Pro Audio Design
Topic: A Second Order Elliptic Equalizer for Vinyl Mastering
Replies: 64
Views: 69467

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: 372828

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: 64
Views: 69467

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: 372828

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: 64
Views: 69467

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: 372828

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: 372828

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: 372828

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 ...