Turntable Pre-Echo Sound....?


When I turn my system up fairly high, I can make out a faint "pre-sound" of what is about to play, with the beginning of the songs starting very, very quietly about 3/10 of a second before it actually starts.

At I thought it could be my stabilizer brush fibers accidentally acting as little styli ahead of the needle, but it does this even with the brush locked up.

Equipment:
Linn Basik TT
Linn Basik Plus tonearm
Shure M97xE cart
Pro-Ject Phonobox preamp
Harmon Kardon AV240 receiver
NHT 2.5 speakers
Cheap interconnects

Thanks in advance,
Dusty
128x128heyitsmedusty
The post-echo and pre-echo occur mostly with loud passages succeeding or preceding quiet ones. When adjacent grooves are about equally modulated, the echo is masked. When levels are moderate, the effect does not occur. Also, good mastering reduces the effect. The idea is to space the grooves wider during loud passages. You can examine a classical LP and see this.
are you sure that it continues throught the record or is it lmited to certain areas on the LP?

Yes it must do. It is a physical limitation of the way LP's are cut. LP = Long Play = some compromises are naturally required to get that extra music compressed (the RIAA curve etc)...this is analagous to good MP3 algorithms that make careful choices to get a compressed audio file that is often (but not always) indistingushable from the uncompressed version.

However, the audibility of this noise (I think of it it as a higher noise floor rather than distortion) will depend on an almost endless number of factors; loud passages close to soft ones, how many minutes of music is on the LP and how close the grooves are cut, the dynamic range of the music itself (more dynamic range will make the cutting of the master more tricky), the outside of the LP or the inner part of the LP... you can go on and on.

In general pre-echo is rarely a problem and even at the start or a track (the worst scenario) it is barely noticeable on the vast majority of LP's.

Fortunately those making the LP are well aware of these issues and will adjust the cutting paramters and choice of where to place tracks such that the LP sounds best (loudest tracks often on the outside).
Shadorne...I agree that "higher noise floor" is a better description than "distortion". It can and is controlled by cutting technique to a level which is inaudible except during silent grooves. I doubt that anyone tries to make it better than inaudible because that would unacceptably limit playing time. But audiophiles like to worry about imperfections that are inaudible, and sometimes nonexistant. Pre-echo does actually exist.
I agree with UC -mostly- on this one, although working with mastering LPs, I find that pre-echo is actually a tape phenomena rather than LP. It indicates that the tape was stored before the LP was mastered- not a good idea as the energy of the tape goes down even over a short time. It also indicates a thinner tape, possibly wound a bit too tight on the reel.

All are issues that are easily dealt with given a little care- but since when have major labels been all that careful? They jumped on digital for the sole reason of cost- cutting the cost of the master tape- now look at the mess they are in!
So are we saying that the problem comes from the way the groove itself is cut, or is it a symptom of cutting a record from a tape with pre-echo on it?

If the answer is "both," then essentially there are two different types of pre-echo: Pre-echo cut into grooves because there was an error in the cutting (an error of the grooves) and pre-echo cut into the grooves because the tape told it too (an error of the master tape).

Is this true?