2. analog
  3. 193643-191808

Rumble - turntable or background noise DG LP

Context: Not really audiophile guy. Set up: AXR 100, Debut Carbon w/Ortofon Blue, KEF LS 50, BW ASW 8 Sub. I am a subscriber to LA Phil so I know what things should sound like. 

I notice a fair amount of what I would call background noise and sub flutter or pulsing when I play Dvorak New World - Berliner/Kubelik and Beethoven 6 Wiener/Bohm. Both are new DG and "remastered". The sound otherwise is very good but the background noise is annoying. When I play C Botti Vol 1 on Blue Note, or one of the 45 RPM  like Brubek or D. Krall they are really quiet. You have to want to find the noise. I have double checked the stylus for proper set up. 1.8 on the nose by measurement. Any idea on why the DG's would be so much worse? I have compared the DG vinyl with the same DG CD's and well, for reasons the defy explanation, I like the sound of the vinyl much better except for the background noise.

Thanks

sbsail9

Showing 2 responses by mulveling

mulveling's avatar
mulveling
2,118 posts
 

Rumble filter is a good idea. The ones built into phono stages generally range from mild to "really mild" and often won't save you in situations like this. KAB's standalone rumble filter is much much stronger, and can help a lot. But the fact that OP can hear the noise means it's at least partly above 20Hz, which is above the range of these filters. 

mulveling's avatar
mulveling
2,118 posts
 

It’s possible the rumble and flutter are being amplified from feedback. Especially with a sub, it can push out a lot of energy to excite resonances on your rack, plinth, tonearm, etc. If that’s the case, better isolation will help a ton. You can "easily" test if this is the problem - by listening through headphones (speakers off, subs off) and seeing if you enjoy much better signal-to-noise ratio.

I’ve heard inadequate isolation manifest as a rumble sound, and as a hum that sounds much like a ground loop. These types of feedback are particularly insidious because they can get to a point where they runaway (keep increasing), which is dangerous.

Also dangerous is woofer flapping (subsonic energy), ESPECIALLY on those KEF’s! Unlike per cones, those drivers cannot tolerate excursion at all past their limits (search for ample photo evidence of busted KEF drivers). Thankfully you’re protecting them with a sub (assuming you run a high-pass filter on the KEF’s - if not you need one or you run risk of breaking the drivers), but too much energy isn’t good for the sub either and it will contribute greatly to feedback into the table.

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