Stylus Rake Angle


I am trying to set up my new VPI 3D arm as close to perfection as I can. On the Analog Planet, Michael Fremer gives one opinion, however, a different opinion was voiced by Harry at VPI, and Peter at Soundmith. I've been discussing this with them....Fremer says that SRA should be adjusted even if the back end of the arm is WAY high up as needed, whereas Harry, and Peter said to start with the arm in a horizontal position and move it slightly up and down to find the sweet spot. Peter said that my cartridge (Benz LPS) and some others have an additional facet in the diamond so bringing the arm up in back would be exaggerating the proper SRA. When I wrote back to Fremer, he answered with an insistance that he was correct. Does anyone want to add to the confusion??
128x128stringreen
Although the setting the arm at the horizontal position by eye works for most arm/cartridge combos, isn't the advantage of using the microscope to set SRA come down to being able to set a good ballbark VTA for those cartridges that have more unusual cantilever/stylii angles or sylii with unusual sensitivity to SRA (micro line, shibata etc.)?

-Karl
I thought this SRA stuff was over the top but I am not so sure now. I track an old, re-tipped by Soundsmith, Koetsu rosewood signature fitted with an enhanced line contact (original Aeries 1 deck/arm). I read Fremner's article and even downloaded the original '81 article and thought it was worth trying. Previously I have always set the cartridge base to parallel and tweaked from there, usually ending up with the back of the arm a little lower. My system sounds quite good considering the components but some voices, etc. are still not quite right (ssssssss'ing/S's too emphasized occasionally/etc.). Cannot justify currently the price of the digital 'scope so I just did a crude check using a x30 illuminated jewelers loupe with the needle on a CD (so they ARE useful for something). As far as I could tell (and I do use microscopes routinely/microdissections) my SRA was >92o. I therefore lowered my arm significantly so the SRA seemed closer to ~90o (all guesstimates but possibly with a trained eye!) and low and behold the sound improved exactly as Fremner described: smoother more easy, natural sound BUT with more detail! For example I quite like/pretty familiar with the album "Survival of the Fittest" by the Headhunters (Herbie's backing band for his album amazingly called Headhunters!): on one slow track a shaker of some sort moves slowly from right to left producing 3 clear shakes, now I can "see" that shaker shaking clearly in space moving realistically across the soundstage- I was gobsmacked. The difference was minor but to my ears very significant. Now I cry even more when listening to the MFSL pressing of LIVE/DEAD. Everything now seems more psychedelic!(Fremner has used this term too- believable illusions).
So perhaps it might be worth trying it, even with a crappy x30 lens 'cos this crude guesstimate seems to have produced a significant improvement.
This is some good hints on setting VTA.

"Raise the VTA (raise the rear of the arm) and the highs will usually get better. Too much and you will lose the bass.
Lower the VTA and the bass will get stronger. Too much and you will lose the highs."

From:

http://walkeraudio.com/lloyd-walker-on-fine-tuning-your-turntable/

I have been playing with cartridge loading. It is interesting that I hear some of the same differences from loading changes as described above with VTA changes. Nothing ever seems easy. LOL

Bob
Karl_desch,

It's hard to imagine anyone designing a cartridge for something other than headshell-parallel-to-LP-surface. Why would they do that? It would restrict sales of their own product. Every tonearm on earth, even the wacky RS-A1, is designed to place the cartridge mounting surface parallel to the record.

This doesn't change with stylus profile. I have cartridges with all sorts of styli: conical, elliptical, micro-ridge. All sound best with the tonearm (fairly close to) level. A touch of tail up or tail down? Perhaps. But nothing extreme.

This makes Fremer's reported advice (in the OP) to jack the back of a tonearm up very high quite suspect. He either didn't say that or he wasn't thinking clearly when he did.

***

Peter,

Your recollection of what I hear when tweaking SRA was accurate. The most concise description I've heard was Frank Schroeder's, "Adjust for proper timing between fundamental and harmonics." He said that and moved on to another subject, as if he'd described everything we needed to know. And so he had.

If someone doesn't know what that sounds like, they need to get away from amplified music and listen to acoustic instruments in natural environments. It's easy to hear mis-timed harmonics in a mandolin or harpsichord pluck. Electic guitars are more congested. Tracker-action organs like the one E. Power Biggs built in Cambridge are easy, at least when played staccato. A Sears Silvertone? Not so much.

Of course the more resolving the cartridge and system, the easier this is to hear. Lower resolution setups may not reproduce enough audible harmonic information. If they do, they may smear things enough so that timing shifts actually do sound like a change in frequency balance. This may account for different descriptions of what people hear when adjusting arm height.

Dear Stringreen: ++++++ " What I did today was LISTEN. " +++++

that's all about.

+++++ " The arm is a bit high, but not absurdly so which the microsope dictated. " +++++

as Dougdeacon I posted several times that those 92 degrees could be a start number as could be 89 or 91 or whatever. 92 is not a compromise, perhaps and only by coincidence ( at random ) what you listened in a specific LP grooves can be that 92 but in the next one will be different.

LP are way imperfect items. For some time now and in some LP titles I bought two samples ( same lot. ) and I can tell you that even here both can/could sounds tiny different.

Now, what's important is to have a well proved VTA/SRA self test process that in almost any " escenario " can works and be repetable.

That test process must has a reference/standard against you will/can compare it. Best reference can be live music at near field listening because normally recording microphones are " near field " position against where we are seated in a concert hall.

IMHO could be a mistake to make comparisons against our latest set up when that set up was made with a different reference/standards. In the other side and even with the same reference we have to ask our self: what if that set up was " wrong " even that we like it and that we are accustom to?

++++ " Because the arm was raised, the VTF is now probably a bit too light, the Azimuth, is probably skewed....I'm too tired to futz with this arm.... " +++++

not only that butyou need to reset something more critical: overhang, because if not then you will have always a higher tracking distortion and all the other set up parameters could help almost for nothing because the overhang was moved with those VTA/SRA/VTF chanes.

Now, the right cartridge VTA/SRA set up depends on the audio system/room quality performance level and your self knowledge level on how live MUSIC ( near field. ) sounds.

IMHO DYNAMICS is the main live MUSIC characteristic that we " want " to even in our system ( with out success. ) and the one that contribute the more for comparisons. Main definition of that Dynamics is how we perceive both frequency extremes in a live event, any deficience in the bass range or HF range goes against dynamics. Precision, definition, accuracy, velocity and natural coloration and agresiveness are part of changes on dynamics.
I think we have to look for in our systems through analize quality performance at both frequency extremes and very especial on the bass that IMHO put the frame for the reproduced sounds in he audio system.

Regards and enjoy the music,
R.