@richardbrand If I'm not mistaken, Thoren's came up with the suspended platter design. I understand the basic idler drive design but not as much as yourself as I've never owned one. Let me rephrase my comment from earlier, people have told me that the motors in the idler drive tables like Garrard or Thoren's are big and loud. Is this true or not the case at all?
Where do classical vinyl records get their rumble from?
Recently converted back to vinyl from silver disks, I am struck by how much rumble seems to be inherent in the new and used vinyl I am buying.
A case in point, is a recent Deutsche Grammophon (DG) recording (487 7484) of Mahler’s Second Symphony made at a live performance at the Sydney Opera House (I was there). The first set I bought was amongst the dirtiest pressings I have ever had, but the second set was much improved. However, there is a persistent rumble whether played on my Holbo Mk2 air bearing system or my venerable Garrard 301 (new bearing from Classic Turntable Company).
Mahler typically has huge dynamic range, from muted off-stage performers to hundreds of musicians going hell-for-leather.
The rumble could be partly caused by the venue’s air conditioning system, but I hear similar background on a Telarc recording (Stereo 10051) of Saint Saens Organ Symphony made in Philadelphia. Telarc even arranged to have local roads shut down for the recording sessions.
Similar efforts were made by DG when recording the organ at Notre Dame in Paris, where recording was done late at night to reduce traffic noise. My copy includes Dolby Atmos on Pure-Audio Bly-ray (DG 486 1466).
I was beginning to think the rumble was inherent in my tables, but then I played a German Direct Metal Mastered (DMM) set from In-Akustik for Clearaudio’s 40th anniversary (INAK 78051 2LP). It includes some Telarc tracks. This set has the quietest background I’ve never heard. There is virtually no rumble, exonerating my tables.
So apart from the recoding venue’s air conditioning and traffic noise, why do so many classical records seem to have built-in rumble? Could it be from the mastering lathe?
I am really only thinking about classical recordings where the dynamic range approximates the signal to noise ratio of vinyl, meaning that very low-level signals are musically important, while simultaneously bumping against the noise floor.
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@richardbrand I have about 7,000 LPs and don't have rumble issues on them except for the very few LPs recorded at Kingsway Hall under which a subway ran. Those LPs are famous for that (mostly EMI). I have stayed mostly away from DG recordings since their microphone technique seemed inferior to me as compared to Decca, EMI, Mercury or RCA. They have done a few that are quite good though. I do not regard Archive as part of that mic placement issue. But no rumble. My main speakers are flat to 20Hz as are my subs (used to break up standing waves in my room). The phono section cuts off at about 2Hz. My arm and cartridge match pretty well so the mechanical resonance falls within the recommended 7-12Hz window. If the mechanical resonance is outside that window you can encounter problems with low frequencies! You've mentioned the use of a turntable with an air bearing. This is entirely the FWIW Dept.: There should be zero slop between the platter surface and the mounting of the cartridge. As best I can make out, air bearings do not satisfy that requirement. The more slop there is, the more difficulty involved getting the cartridge to track properly and not pick up artifacts from the turntable itself. An air bearing for a platter can oscillate up and down (there might be a means of stabilizing that of which I am unaware...). Any microscopic movement in that regard can be interpreted by the cartridge as a signal. Idler drive turntables are also known for lessor rumble noise floors. It is why there are belt and direct drive turntables. As yet I'm unconvinced that your LPs are the problem. Your surmise that classical is the most demanding in terms of surface noise is also incorrect. There are many non-classical recordings that are just as demanding of the noise floor of the LP. FWIW, I ran an LP mastering operation for about 20 years. Mastering lathes of course generate some rumble too, but the savvy operator of such devices knows to run the lathe for 20-30 minutes to warm up the bearings (if an older style lathe, such as the Scully we ran). I think we can rule out the mastering lathe since they do any and all recordings made though. |
No, rumble (whether from table or record) is just more noticeable because of the huge dynamic range in some classical music, especially large-scale romantic orchestral / choral works. When the music is very quiet, it is on a collision course with the noise floor of your gear. To those who cannot hear the noise floor, turn your volume up until you can. |
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