We all love our vinyl but let us not forget its many flaws. In particular, inner groove distortion.
When vinyl spins the stylus follows in a spiral pattern. That spiral brings us ever closer to the center of the record where there is less and less room for modulation (think of the difference between the open and closed state of an accordion’s bellows). As we near the disc’s center, it becomes harder to play loud passages without distortion because there is less room for the big wiggles necessary for loud music—and the louder the passage, the more distortion we’re likely to encounter.
To combat inner groove distortion, recording and mastering engineers prefer to place softer cuts of music near the end of the disc, reserving an album’s first tracks for the loudest (where there’s more room for big groove wiggles).
Which brings us to the Beethoven problem. Beethoven’s 9th symphony has a pretty wild and loud finale that is by default found at the end of the record—right where it’s hardest to reproduce without distortion.
Part of the problem is found in the difference between how records are cut versus how they are played back. Mastering lathes use a linear tracking arm, meaning the cutting stylus is perfectly aligned from start to finish. Most turntables, on the other hand, use a pivoting tonearm, which can only line up correctly at two points across the record surface (it’s a fact of geometry). A properly configured, high-quality turntable with a minimum 10-inch tonearm can reduce tracking errors significantly, but tracking errors will always be most noticeable at the inner grooves – thus further encouraging end-of-side distortion.
We can solve some of this by moving from a pivoting tonearm to a linear tracker, but these two have their own problems.
The better the turntable arm setup the more you can reduce the effects of inner groove distortion, however, you cannot get rid of it easily.
So, the next time you spin Beethoven’s 9th on vinyl, you’ll have to be a bit forgiving of the finale’s wild dynamics.
ht: to Marc in smokey Oakland for this riff
Paul McGowan / PS AUDIO
