View Full Version : 3 more, one tricky one. lossy?

2012-03-09, 06:43 AM
audience tape from 1980

http://img221.imageshack.us/img221/9610/801116sa.jpg (http://imageshack.us/photo/my-images/221/801116sa.jpg/)

it wouldnt let me generate a frequency analysis, it just turned out blank over and over

an aud tape of a 1992 soundcheck

http://img543.imageshack.us/img543/7967/920905sa.jpg (http://imageshack.us/photo/my-images/543/920905sa.jpg/)

and a frequency analysis

http://img816.imageshack.us/img816/2506/920905fa.jpg (http://imageshack.us/photo/my-images/816/920905fa.jpg/)

and the tricky one
a 1998 aud tape
note how the frequency analysis doesent show a drop
could this be a minidisc recording. would that make the lego block skyline in the spectral analysis?
http://img402.imageshack.us/img402/7712/980628sa.jpg (http://imageshack.us/photo/my-images/402/980628sa.jpg/)

and its frequency analysis

http://img195.imageshack.us/img195/1167/980628fa.jpg (http://imageshack.us/photo/my-images/195/980628fa.jpg/)

Uploaded with ImageShack.us (http://imageshack.us)

2012-03-11, 08:36 PM
My opinion in this exact order is mini disc [atrac], DAT, mini disc [atrac]

2012-03-12, 12:23 PM
My opinion in this exact order is mini disc [atrac], DAT, mini disc [atrac]

really? dat on the second one? even with the blocks and black void blocks?

2012-03-12, 05:10 PM
Yes with 99% certainty. I would be able to be certain if it was in black and white but I'm basing my decision on this DAT sample in the sticky http://www.thetradersden.org/forums/attachment.php?attachmentid=6575&d=1124725206

2012-03-12, 05:26 PM
Can you send me a snippet of a wav file and i'll give it a look.

2012-05-30, 08:28 AM
Can you send me a snippet of a wav file and i'll give it a look.

Yes, this. Tho 1 and 3 don't look good at all.

2012-06-18, 04:23 AM
#1 and #3 MD with analog transfer

#2 I believe is also lossy, it doesn't have the cutoff like a 32kHz DAT. I think its a strange codec, I have one blind melon track from about 1992 that looks very very similar to this and it sounds lossy as well. little blocks, red stripe its really really close maybe from the same trader.

2012-06-18, 05:40 PM
Five droppin' knowledge. Welcome back. :wave:

2012-11-27, 01:12 PM
i agree 1 and 3 don't look good at all

2012-11-28, 09:40 PM

All three are lossy.

Sorry for your lossy.

Great spec-anal shots, though! :thumbsup

P.S. Frequency Analysis isn;t indicative of lossy data compression, one way or the other. Sometimes, if a certain codec rolls off the high end as part of it's scheme, you'll see a drop, but:
1) not all codecs do that
2) a drop off in freq response is not always indicative of the presence of a lossy audio codec.

Fallacy: all lossy codecs roll off high frequencies. <<<--- NOT TRUE
Fact: all lossy codecs remove chunks of audio to shrink the data file size.

- There are many cases where high frequencies may be rolled off in the analog domain and it just doesn't prove anything.

- There are many cases where high-quality lossy codecs leave the high frequencies intact (iTunes does this).

- You can ALWAYS see the chunks' holes after removal in a spectrum slice - around a 2-3 sec span. This is the best way to determine if a lossy codec has been applied. ATRAC won't be as severe as MP3.