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Last song on most LP's pressed with compression

Over the last few yrs, I have spent more time with my cd player than analog rig. Anyway, the winter is here and I'm feelin the groove and started listening critically to LP again. What bothers me is the last song on a side is often compressed. You have hear this as a reduction in sound quality, akin to what an MP3 does to a cd original. Now if you inspect the LP closely that bothers you. You can see visually that the grooves towards the end are actually cut into the record differently. They are compressed together. I don't care what cartridge or equipment you use, the distortion is there..period . Once your brain locks onto it, listening thru this distortion is very difficult. Now before the experts chime in, I'm not talking about inner groove distortion here. Nor is there anything wrong with my alignment,VTA, tracking,azimuth etc. If you can't hear this on your rig (with an LP that is cut compressed on the last track- not all are)then no doubt your system is not resolved enough. Part of my LP collection (about 500 records)are 12" singles. These do not suffer from this problem for obvious reasons. But I'd bet that 60% or more of regular LP's do. What all this means for me is that the days of investing big $$$ on LP playback are over. What I have is what I have and when it eventually wears out, I doubt that I'll replace it. Yup, I am that bugged by wasting a portion of my valuable listening time listening to a lower quality signal. I modify my own equipment to achieve the highest quality signal that I possibly can. So subjecting myself to a flawed LP format is a step backwards. Before I play an LP now, I examine that groove pattern towards the end. If it looks extra compressed, then back on the shelf that title goes. I'll pick the original (non maximized) cd version every time.

Feel free to chime in.
reb1208
halcro's avatar
halcro
2,664 posts
 
"If you can't hear this on your rig (with an LP that is cut compressed on the last track- not all are)then no doubt your system is not resolved enough."
Hmmm........I don't hear it on ANY records so I guess I need to get rid of those damn arms (Copperhead and DaVinci Grandezza) and get a decent turntable to boot (rotten Raven AC-3?).
Perhaps you might enlighten us as to the brand of your super-resolving turntable and arm?
And then you might inform us as to what tool you use to adjust the arm/cartridge geometry?
kirkus
502 posts
 
"Compression" is absolutely the correct term . . . it's dynamic range compression and it's common practice to apply this to the inner tracks during mastering. As others have pointed out, this is done because the linear groove velocity has decreased, and thus a given stylus acceleration corresponds to a lower modulation level. And the tracking performance of ANY cartridge is of course related to the stylus acceleration.

Simply looking at the groove spacing, however, will only give you very little indication of how much compression has been applied. In the 1970s, sophisticated computer programs were developed to control the progression of the lathe's cutting head as it moved across the record, to maximise the utilisation of the available space for the recording . . . and a visual check will only give you an impression of how effectively this was done. Had the groove spacing been increased . . . the compression would still be there.

Groove spacing does affect the amount of "pre-echo" heard, but this is of course much more noticable at the beginning of the record, not at the end . . . and there are other things that affect this, like the processes of plating the lacquer and making the stamper.

The reality of the situation is that we owe a great debt to the mastering engineers who have given us those records that sound great from start to finish, in spite of the necessary compromises involved in doing so. And while some of the harshest words on Audiogon forums are reserved for the CD format . . . this is THE format that brought us extremely consistent performance across the entire recording, in one contiguous block of time.
reb1208 OP
518 posts
 
Halco, it appears that you are quite fortunate. In addition to your very impressive analog rig, its obvious that your LP collection is comprised of only the finest cut records of all. Congratulations, it must have been some effort to put that collection together. Enjoy, and good listening!!! Oh, BTW how old are you if I may ask. I'm 47 and can easily hear that high pitched text message kids use. Most adults can't, get my drift.
danmyers
135 posts
 
"Normal hearing loss due to aging consists of a gradual decrease in high frequency sensitivity over time. The chart is from Modern Sound Reproduction by Harry F. Olson. It shows the average hearing loss Vs age for men and women at frequencies from 250 Hz to 8000 Hz. This means that for a man at age 35, sensitivity is down about 11 dB at 8000 Hz. For a woman at that age, sensitivity is down only about 5 dB. This varies, of course, from person to person but we can infer that sensitivity is down even further at 20kHz."

The accompanying graph is frightening with HF hearing loss increasing (or is it decreasing?) by about 10 db per decade. Makes me think I should really only be buying subwoofers from here on out :)

http://www.roger-russell.com/hearing/hearing.htm
halcro's avatar
halcro
2,664 posts
 
Reb,
You conveniently forgot to enlighten us on your turntable/arm/cartridge combination and the protractor tools you use to set up the alignment of your arm/cartridge?
Incidentally, I can easily hear the the 18K Hertz tone on the Stereophile Test CD.
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