Mono recordings

Started by bluewater, January 28, 2007, 15:00:11

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bluewater


I started to remaster to my own use the birmingham ´89 show which is
a mono recording although it has distinct left and right channels
that differ only in volume and compression. I was wondering what to do
with this kind of mono recordings? How many audience recordings are there
from the 80´s that are stereo? I started to downmix the channels to
mono (using average method) and started to think what is the best
thing sound quality- wise to do with these? If downmixed to mono
no information is lost and it goes 50% smaller size when encoded to flac.
However i haven´t noticed many recordings that have been downmixed. Is it
legal to do so and what do the collectors think about it?

-bluewater
Life's too short to listen to lossy music

bluewater


In other words : is it considered lossy encoding if the channels are
balanced by

left = 50% left and 50% right
right = 50% left and 50% right

then it goes to half the space when encoded in flac. If there´s no stereo
information in the channels (=if it's mono) then it should also sound better and balanced this way. or?

-bluewater
Life's too short to listen to lossy music

lostflower4

Quote from: bluewater on January 28, 2007, 15:00:11

I started to remaster to my own use the birmingham ´89 show which is
a mono recording although it has distinct left and right channels
that differ only in volume and compression. I was wondering what to do
with this kind of mono recordings? How many audience recordings are there
from the 80´s that are stereo?

This is a good question. Seems most recordings are in "stereo", at least in the fact that the left and right channels are not 100% equal. I'm aware that many of them may very well be mono recordings, and due to the imperfect nature of analog duplication, the levels will fluctuate, creating an "illusion of stereo".

As to how many true stereo recordings there are, I can't say. I wasn't old enough to be recording shows in the '80s. :lol:  I think some of the mics could do stereo, or at least "pseudo-stereo" where two independent channels were made. But I'm afraid I don't know many exact details about this.

If you take a known mono recording that has changed over the course of generations, I don't think there is anything "wrong" with averaging the channels back out.

You're right that if something is mono, the FLAC file will be half as big. FLAC is very intelligent in the way it encodes, so even if you have a "used to be mono" recording, and the left-right levels are only slightly different, it will still compress much more efficiently than something with true stereo separation.

As for it being "legal" to do what you're speaking of, as long as it was originally mono and you're certain, I think it's fine. After all, this is actually more original â€" which is what many serious collectors are looking for. How many people actually do this? I would have no idea.

I have some digital recordings with identical left-right channels, and it's impossible to know if it's the way they were recorded, or if it's the way somebody edited them at a later time... :?


bluewater

A few more examples.

-London 1990 crystal palace show

this is frozen to 32khz dat and this is also
a true mono recording, but has not been downmixed. It goes to much smaller size when downmixed.

-a wembley arena 1989-07-22 recording

this is an "illusion stereo" recording that cannot be downmixed without
technical problems.

-paris, zenith 2000-04-26

from the bootleg "dream tour". this is either illusion stereo or narrow-stereo
recording. Could be dat or minidisc, this can't be downmixed.

-new orleans 1996 Dat (upped by lostflower, thanks)

this is a narrow- stereo recording. It can't be downmixed.





Life's too short to listen to lossy music

bluewater

About the size differencies. The london 1990 show goes down from

928 Mb Flac - > adobe audition, channel downmix to mono - > 480 Mb Flac

so it really counts...

-bluewater
Life's too short to listen to lossy music