VTA and HTA overhang

The problem is twofold, overhang changes with arm height and SRA varies from 91 to 95 degrees. Even Jon Risch* (the guy whose work this is based on) said that 91 degrees is right for 80% of all records. In reality, I think most people who occasionally change arm height for a record, usually change it a small amount. A 9" arm requires 4mm height adjustment for 1 degree change. Who set up the alternatives of changing for every record, or not at all?

If you use a Loefgren A or B alignment set at 92 degrees, then raising your arm slightly won't do much to alignment. Any two set of nulls between 60 and 121 mm, is a "good" alignment. Look at the nulls for Loefgren A, B, and Stevenson. If you're skeptical, get a straight line calibrated grid, raise your arm 2 mm and see where the nulls are. IMO SRA errors can be much more audible. Some people don't seem to hear it, but some people are nearly oblivious to speed variations.

Put a UHQR on your table, and in order to maintain your orig alignment the arm must be raised the same amount of extra record thickness. Look at the record and arm pillar as 2 sides of a right triangle. The arm tube to stylus is the hypotenuse. The alignment change is very small and SRA goes negative, Sound a little bassy?

*Audio magazine March 1981

Where did the notion of perfect alignment originate? It is only tangent at 2 points throughout the record side, whatever alignment you choose. Wax poetic about your wonderful alignment, but it is only choosing one set of errors vs another.

What about the null throughout the record, when the stylus is or is not vertically aligned with the angle/cut of the groove undulations? Why is that unimportant, because Roy Gandy can't hear it, or it's cheaper to make an arm without height adjustment?

In reality, if your arm height is set so SRA is right for the "average" record, it won't have to be changed for every one. The majority of records will sound right. But for the occasional record that is obviously off (assuming you can hear it), a small change in height will have little affect on horizontal alignment, and great affect on vertical alignment.
Regards,

Hi Searcher, Actually, Baerwald (Loefgren A) is least average error across the entire record i.e. even amount beginning, middle, end. Loefgren(B) is least total error. That's because nulls are closer to the middle where error is the greatest, but error is a little higher at the beginning. Stevenson puts the inner null at the lead out groove to help with inner groove problems. There's no right/wrong. I've aligned many arms designed for Stevenson with nulls between there and Baerwald. IMO it worked out better.

Why only consider horizontal aspect? Tracking is 3 dimensional. If SRA is off, it effects playback of the entire record. If someone finds occasional height adjustment to sound better than not, how can you question that?

Sarcher30, I didn't mean to imply that you took a position, that you really didn't. I should have addressed my last comment to "anyone who". Sorry.
As far as the various alignments, you still have them mixed up. Baerwald goes for even error at beginning, middle and end. Loefgren B has least total error. Maybe description on VE is confusing, but nevertheless.
Regards,

Sarcher, That's better. Maybe it was use of terms, not sure.

Anyway, "The people that try to get the perfect SRA for every record must believe that it's more important than perfect alignment. I doubt there are many people that would go to the trouble of adjusting overhang for every record as well."

I know that's taken out of context, but that perception was what I was addressing by statements about percentage of records needing correction, and viability of resultant alignments. If SRA is set for 92, then additional SRA angle results in less overhang from raising the arm. It's true that angle changes slightly but less overhang would put a Baerwald alignment a hair closer to Stevenson. A small change in height results in a much smaller change in overhang, depending on eff length, plus most records don't need correcting.

After many thousands of records, it's a trade-off I might make to optimize SQ. Hence the popularity of on-the-fly adjusters. The only problem with some of them, is they compromise mounting integrity. Some linear arms are a particular problem with respect to changing SRA, those with a short arm tube.
Regards,