SQ decoding using Adobe Audition

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sam77aus

Member
Joined
Apr 18, 2005
Messages
27
Location
Australia
Hi all,
I new to this forum but so far it has been very helpful to me, reading through various posts has been quite fascinating. I’ve been aware of quadraphonic for many years now (I am now 27) since playing one of my fathers records when I was about 10 years old and noticing the record sleeve had some information about it being in quadraphonic. The record was a CD-4 as I now understand it, but back then I wasn’t aware that there were three competing LP quad formats. I played this record on my father’s stereo (which I now realize was a QS system) and could not hear anything but stereo coming from the four speakers. Turns out he didn’t even know there where three competing formats, guess he must have thought all quadraphonic records were the same. I remember when I asked him about quadraphonic he simply replied “oh it’s no better than stereo”. The only other quad records we had were SQ ones, so playing those on our system would have only produced stereo through four speakers as well.

I came across Tab’s site a couple of years back and found it very interesting, I started to become interested in quadraphonic and the various titles that were released in this format.
I had a few records converted to DTS and was happy with the result. Lately I have been trying to do a few conversions myself with Adobe Audition, the results were ok but there is sill a bit of audio leakage across channels. It could be my cartridge alignment (I am using a AT 440ML cartridge with an Origin Live silver tonearm on a Michell GyroDec SE turntable). I have tried a few different settings in Adobe Auditions center channel extractor but have not found the perfect settings yet, not that I can fully understand some of them anyway, has anyone found the best settings for decoding SQ?

Also I have found copies of Pink Floyd’s three SQ quad albums released on rare limited edition CD’s. I have not received them yet but when I do I will try decoding them with Adobe Audition.

Samuel
 
sam77aus said:
I had a few records converted to DTS and was happy with the result. Lately I have been trying to do a few conversions myself with Adobe Audition, the results were ok but there is sill a bit of audio leakage across channels. It could be my cartridge alignment (I am using a AT 440ML cartridge with an Origin Live silver tonearm on a Michell GyroDec SE turntable). I have tried a few different settings in Adobe Auditions center channel extractor but have not found the perfect settings yet, not that I can fully understand some of them anyway, has anyone found the best settings for decoding SQ?

There is a inherent flaw in the decoding but this time it's not the SQ fault. Problem is, even playing a LP with a Laser Turntable will lead to channel crosstalk, because this is present right from the start on the cutter lathe. The cutting stylus is a *single mechanical device* and there's no way to recover a full 60-70 dB separation from a LP. This, IMHO, *is* the basic source of a problematic decoding, and it's easy to compare it if you try a SQ master that made it into CD. The results are really different, all due to the total separation L/R of the cd media.

In short, there will always be a leakage in the -25-35 dB area because this is inherent to the LP media. Applying a amplification factor, such as the "logic" decoders, will raise the separation but will introduce the hated "pumping sound" that no one wants.

The only possibility to improve a bit the thing is to add a small amount of a channel to the other with a 180 deg. inversion. It will work a bit but, again IMHO, will work good only on a linear tracking turntable, because it does respect the original geometry with which the disc was cutted.
 
winopener said:
There is a inherent flaw in the decoding but this time it's not the SQ fault. Problem is, even playing a LP with a Laser Turntable will lead to channel crosstalk, because this is present right from the start on the cutter lathe. The cutting stylus is a *single mechanical device* and there's no way to recover a full 60-70 dB separation from a LP. This, IMHO, *is* the basic source of a problematic decoding, and it's easy to compare it if you try a SQ master that made it into CD. The results are really different, all due to the total separation L/R of the cd media.

In short, there will always be a leakage in the -25-35 dB area because this is inherent to the LP media. Applying a amplification factor, such as the "logic" decoders, will raise the separation but will introduce the hated "pumping sound" that no one wants.

The only possibility to improve a bit the thing is to add a small amount of a channel to the other with a 180 deg. inversion. It will work a bit but, again IMHO, will work good only on a linear tracking turntable, because it does respect the original geometry with which the disc was cutted.

Thanks for that information, makes sense to me.
I was also wondering what settings the numbered values in your automated script (for Adobe Audition SQ Decoding) referred to, so I can tweak the settings in the center channel extractor.

Thanks
Samuel
 
mandel said:
By reading the sticky thread about decoding SQ on a PC
You know what's funny is that I did read that thread above right after posting that, and I thought to my self, "Oh, now I see what they are talking about."
 
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