digitalfrost
Major Contributor
So my last post actually got my thinking about this topic again, and if we agree das Löfgren A is the best solution, just for sake of simplicity and because I believe it is, other interesting things come up. With IEC standards for inner and outer grooves, the maximum tracking distortion is 0.62%. With a DIN inner groove radius it raises to 0.69%.
I looked how up big vinyl labels are, and they are either 100mm or 4" which is 101,6mm. So, let's assume we have this one record that goes over the (worst case) DIN standard and is longer than 57.5mm inner radius. Whatever the vinyl label radius, if we add either 100mm or 4" to 57.5mm halved we arrive at ~54mm rounded. Middle value. That surely is some kind of worst case vinyl record because none can go right until the label right.
I come from an IT/infrastructure background, where stuff just has to work like the water supply or the power system. So you just err on the side of caution and build stuff that works even under bad (worst) circumstances. We don't ask how good is it going to work when everything's perfect, but how good will it work still if shit hits the fan. Coming back to vinyl.
If I decrease the inner radius to 54mm, maximum distortion is now 0.78%. So I gain ~ 0.1-0.2% in calculated distortion for an alignment that always works, even when the record is bad/against the standard. What's not to like?
Now if you chose an IEC inner groove of 60.325mm and used the Stevenson alignment, you pretty much arrive at almost the same distortion graph. Difference in maximum distortion is 0.02%, however my 54mm Löfgren A solution is 0.1% better at the usual cutoff of 58mm. So any discussion of alignments is useless without specifying inner curve radius.
The real question is how much tracing distortion is rising across the record (probably dependent on needle type) and if you can even compensate that by working on tracking distortion. I'm so pissed of I'd buy a linear tracker if I'd cared enough about it.
There is clearly more at play here than the curve shows. I have never ever thought that in the region where it has that belly towards the lower 3rd of the record anything would not be alright, but I'm sure most know the bane of a bad sounding last track.
To arrive at the optimal null points, we'd really need to know how tracing and tracking distortion influence each other and in how far one can be compensated by the other.
I looked how up big vinyl labels are, and they are either 100mm or 4" which is 101,6mm. So, let's assume we have this one record that goes over the (worst case) DIN standard and is longer than 57.5mm inner radius. Whatever the vinyl label radius, if we add either 100mm or 4" to 57.5mm halved we arrive at ~54mm rounded. Middle value. That surely is some kind of worst case vinyl record because none can go right until the label right.
I come from an IT/infrastructure background, where stuff just has to work like the water supply or the power system. So you just err on the side of caution and build stuff that works even under bad (worst) circumstances. We don't ask how good is it going to work when everything's perfect, but how good will it work still if shit hits the fan. Coming back to vinyl.
If I decrease the inner radius to 54mm, maximum distortion is now 0.78%. So I gain ~ 0.1-0.2% in calculated distortion for an alignment that always works, even when the record is bad/against the standard. What's not to like?
Now if you chose an IEC inner groove of 60.325mm and used the Stevenson alignment, you pretty much arrive at almost the same distortion graph. Difference in maximum distortion is 0.02%, however my 54mm Löfgren A solution is 0.1% better at the usual cutoff of 58mm. So any discussion of alignments is useless without specifying inner curve radius.
The real question is how much tracing distortion is rising across the record (probably dependent on needle type) and if you can even compensate that by working on tracking distortion. I'm so pissed of I'd buy a linear tracker if I'd cared enough about it.
There is clearly more at play here than the curve shows. I have never ever thought that in the region where it has that belly towards the lower 3rd of the record anything would not be alright, but I'm sure most know the bane of a bad sounding last track.
To arrive at the optimal null points, we'd really need to know how tracing and tracking distortion influence each other and in how far one can be compensated by the other.
