Is this amount of record/tonearm bobbing "normal"


Most records sound fine, but a few of them (shoegaze, Interpol) with extended chords sound bad, uneven.

This could all be in my head. I'm new to this.

Kindly take a look at a brief video and tell me whether my platter is warped?

 

 

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Might not realize this, the ones above certainly missed it, but there are four different things going on here. From bottom to top: platter, mat, record, and arm.

Watching the first few seconds it is clear the bottom edge of the platter is oscillating up and down. But the top edge is what counts and hard to tell for sure with your camera bouncing around but it looks like the top is off too just maybe not as much. Anyway for sure your platter is a contributing factor.

Then you have the mat, but it is way too out of focus and jittery. What you should do, place a piece of cardboard or something along side the platter with a mark as reference and watch the TOP SURFACE of the mat. If you are lucky the mat may not be flat. The reason I would call this luck, it is like balancing a tire you might be able to improve it by rotating the thick part of the mat to the lower part of the platter.

Then there is the record. Perfectly normal looking record. Some are dead flat, some are not. This one is well within the norm. That’s not your problem. The platter, that’s your problem.

Finally the arm. It is tracking well not bobbing, nothing wrong there. Bottom line, if it sounds good it is good. This is all within the range of normal LP playback. In other words I’ve seen worse. I’ve had them where the record was so warped it hit the cartridge causing it to go airborne. That’s a bad record!

Nice arm by the way. Graham? Had one myself. Deserves a table better than this. Do what you can, upgrade when you can, other than that don’t sweat it.

Agree - platter looks out of true - not seated properly on the spindle/subplatter

 

Thanks for the feedback. In this case there is a lower platter, an upper platter, a mat, and the record. The lower platter is about 48 hundredths "tall" and you can see it in this video:

 

https://youtu.be/0Tq1hydi-DI

The runout (probably the wrong word) seems like it's about ~three hundredths. 

I can hear it on some records. I guess my choices are a new platter or a better turntable.

 

Yes, millercarbon, it is a graham tonearm. I love it.