Table/Cart Set Up - By Ear or Test Record?

Tonywinsc,
It does require gear at a certain level to hear SRA changes as affecting phase coherence. Lower resolution cartridges mounted on lower resolution rigs (like my old Shelter 901/OL Silver combo for instance) are too muddy to hear this clearly, at least for me. Still, even on such gear, my partner's better ears do hear proper SRA as maximizing the amplitude of lower frequency notes... a function of phase coherence. It wouldn't be wrong to describe inaccurate SRA as "bright" or "dark" on such gear. If waveforms are muddied what's heard earliest may leave the strongest impression.

With resolving gear however, like my own UNIverse/TriPlanar to pick one example of many, I have always heard the phase coherence differential I described... long before I developed the vocabulary to describe it in fact. Frank Schroeder hears this and described it before I was able to. It was a chat with him that gave me the conceptual language to describe what my ears already knew. This is why I can now walk up to an unfamiliar cartridge/arm (like a friend's A-90/Kuzma Airline for example) and dial in SRA in a few seconds. It's pretty easy when you know what to listen for.

I don't dispute that "brightness" is in some audio glossary. It just isn't a detailed enough term to describe what I hear. Appeals to authority carry no weight with me, I listen and draw my own conclusions. :-)

Try visualizing a knife re-tracing a modulated groove cut along a stick of butter. If the knife (stylus) is raked backwards (SRA too low) it will respond to lower frequencies before the narrower tip sees higher frequency harmonics. If the stylus is raked forwards (SRA too high) the opposite occurs. This is a good visual analogy for what I hear.

Actusreus,
There's no question that altering arm height on a straight vertical axis alters overhang at the stylus. This isn't a matter of opinion, it's proveable by the principles of geometry. It could only be otherwise if an arm height adjustment operated on a curved path to keep the stylus tip immobile on the record... a theoretical improvement that doesn't exist on any tonearm I've seen.

Do I adust overhang for each change in SRA? No. I actually do have a life. ;-)

FWIW, tracking angle distortions sound utterly unlike changes in SRA, so while the adjustments are interrelated their sonic effects are quite different.

Doug,
I'm not sure whether I agree with your assertion since you're actually adjusting the VTA tower, which might as well keep the stylus immobile and the back of the tonearm traveling along an arch, albeit a very small one. That said, I'm not a mathematician so I might be misinterpreting what actually occurs in the process. However, if it's true, I'm curious where this leaves the whole discussion about the importance of the precise alignment with protractors such as the Mint. You spend two hrs trying to get the overhang perfect with a magnifying glass only to have it altered at the first VTA adjustment. Yet it is that precise alignment that is behind the claim of the Mint's superiority over less accurate tools. I wonder then whether the obsessive focus on the accuracy of the Mint or similar instruments is misplaced. At least for those who have the ability to adjust the VTA and do take advantage if it.

Actusreus, Nice post. You make the point that I tried to make in my earlier thread on the VTA/HTA topic, only you articulate it much better than I did. I use a MINT protractor and now can adjust overhang in about 15 minutes when changing cartridges, but still, I do obsess over it and get it to match the arc exactly. I find the Zenith alignment at the null points most helpful on the Mint. It is obvious that VTA adjustments alter overhang. I suppose those who adjust VTA on a regular basis feel that the sonic benefits of proper SRA outweigh the penalty of a slightly off overhang.

Actusreus, on any tonearm I know of the VTA tower is designed to move straight up and down, subject only to random variations in the threads. I'm unaware of any tonearm with a VTA tower designed to move on an arc with a radius matching the arm's eff. length. That would be technically correct and I presume it could be done using computer-controlled machine tools, but it would probably be very costly.

Nice summary Peter.

I suppose those who adjust VTA on a regular basis feel that the sonic benefits of proper SRA outweigh the penalty of a slightly off overhang.

They do for us.

That said, the sonic benefits of aligning zenith and overhang with the Mint are also very easy to hear.

I haven't checked visually with my Mint, but my suspicion is that the amount we alter arm height from one LP to another has only a trifling effect on overhang, possibly within the margin of setup error even when using a Mint. That would merely shift the null points slightly, which might actually be superior for some LP's, depending on the diameter of the innermost music groove.

Let's not forget that any chosen alignment scheme (Baerwald, Loefgren, whatever) is a compromise. Only a perfectly set up tangential tracking arm can achieve zero tracking error across the entire LP. On all pivoting arms we're simply choosing between compromises. Such is not the case with SRA. There is an absolute best for that parameter.