Turntable Pre-Echo Sound....?

It's in the record grooves, called "pre-echo". Sometimes it's in the tape as well, due to print-through (in analogue tapes). When a record is cut today, the grooves's pitch is controlled by a computer, which is supposed to space teh grooves far enough apart to keep loud passages from bleeding into adjacent 'quiet' grooves. It does not always work. In the past, before about 1973 or so, this was controlled manually by the disc masterer.

if it's only on your turntable it's probably a kind of bleed-over you get from the adjacent groove on the lp - it's a flaw in the pressing, not a problem with your system

Actually, it's a good sign for your system. Most pre-echoes are at pretty low levels. The more resolving the system, the easier and more frequently you'll hear them.

Wow, I can't believe I actually nailed what the sound is called in my post title. It's literally a pre-echo!

I have never heard of this phenomenon. Do more expensive cartridges make this better, or does their better tracking make it worse?

I saw a cartoon in Stereo Review years ago wherein a customer asked his dealer about hearing the first few notes softly before hearing them at full volume. The dealer replied,

"yes, that's a common phenomenon... YES, THAT'S A COMMMON PHENOMENON..."

Cheers,

Duke

04-16-07: Heyitsmedusty

"Wow, I can't believe I actually nailed what the sound is called in my post title. It's literally a pre-echo!

I have never heard of this phenomenon. Do more expensive cartridges make this better, or does their better tracking make it worse?"

Yes, it's "pre-echo". It comes from two sources:

1) Tape print-through. In thin tape, the strong magnetism from a loud passage can affect the adjacent layers of the tape. This is called "print-through". Good studios avoid this by keeping tapes from winding too tight and frequently rewinding them, so they don't sit in the same position for too long. Also, using thicker base helps, because the tape surfaces are farther apart.

2) Adjacent groove modulation. If grooves are too close together, they can be affected by adjacent ones.

There is no remedy.

http://en.wikipedia.org/wiki/Mercury_Records

"In 1961, Mercury enhanced the three-microphone stereo technique by using 35mm magnetic film instead of half-inch tape for recording. The greater thickness and width of 35mm magnetic film prevented tape layer print-through and pre-echo and gained in addition extended frequency range and transient response. The Mercury 'Living Presence' stereo records were mastered directly from the 3-track tapes or films, with a 3-2 mix occurring in the mastering room."

You can only hear pre-echo during a silent groove, but it actually goes on throughout the LP, and constitutes a form of distortion.

And of course that distortion is inaudible, contrary to the far lower distortion introduced by, say, a digital facsimile of the same recording, which everybody can hear!

Bob P.

04-16-07: Heyitsmedusty
Wow, I can't believe I actually nailed what the sound is called in my post title. It's literally a pre-echo!

I have never heard of this phenomenon. Do more expensive cartridges make this better, or does their better tracking make it worse?

In my experience, line contact type tips usually make this artifact more audible than a conical tip - probably due to taller contact footprint on the groove wall.

This may be one reason that the Denon 103 (which uses a conical tip) actually produces less measurable distortion than some high priced cartridges with line contact tips. I also wonder if this has some bearing on the 'musical', coherent sound that is a feature of the 103.

You can read more on 'groove echo' here.

Eldafort says, "You can only hear pre-echo during a silent groove, but it actually goes on throughout the LP, and constitutes a form of distortion".

Hello, are you sure about this? I have a number of LPs with pre echo. I have never thought about this possibilty.
I must say though that I have never heard any detriment to the sound except for the pre echo. I guess my question would be; are you sure that it continues throught the record or is it lmited to certain areas on the LP? I will listen with this in mind the next time I listen to an LP with pre echo. Certain aberrations on LPs auch as rumble, distortion, groove or vinyl noise can be transient, is pre echo?
Bob

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?

Is this true?

Dusty,

Yes there are two types of pre-echo. The industry move to digital brought about its own new set of issues/deficiencies but pre-echo is one of the many issues with analog that made digital attractive. Those who say it was purely a cost cutting measure are a being a little unkind to the engineering folks at Sony and Philips who developed the CD digital formats. There was no conspiracy against Analog, as far as I know.

It's easy to tell which is the reason. Watch the LP and see if the "real" sound begins one recolution after the pre-echo. That would be 1.8 seconds for a 33.3 rpm. This has always been my observation, although mag tape print through is also real. However, I think this occurs when a tape has been stored for a long time (years) without rewinding. Only analog tapes are affected. For any LP made from a digital tape (and that includes most of them these days) any pre-echo must be from the cutting process.

Mind blown. I thought I was crazy. 

actually it's called 'print- through' for reasons that may be obvious ....

Man...another time jump thread...I get that pre-echo stuff on my rig and it really doesn't seem to have an audible effect on the "proper" musical bits, although logic dictates it should.

Upon cursory review, I think this thread explains the pre-echo phenomenon the best.  Here's a similar explanation from an outside source:

"When you master an LP, you have to put each groove as close to the other as possible. As a result, in loud passages you sometimes can hear bleed-through from the previous groove. (A similar thing can happen in the master tape when one layer of tape magnetizes the next layer on top of it in the reel.) Compromises in the sound must be made to press music in this format, and bass is what mastering engineers have to compress and attenuate the most."

Quoted from:

The Joy of 45 Collecting: Why 45s Sound Better Than LPs (classic45s.com)

 

I'm hearing this in almost every quiet passage of music on LP's, throughout the LP, not just one revolution before the start of the LP.  This effect must induce some low level distortion, possibly 1-2%.  

for a clear example of this, listen to "More and More" from Blood, Sweat, and Tears from their self-titled 1968 release.  You can hear the intro horns very clearly just before the track starts.  I wonder if the end of LZ's "Whole Lotta Love" ("Waaaaay down inside") is an intentional effect or tape bleed.