What is the actual frequency(ies) of record surface noise?

I'm not sure if this post is in the correct forum, but I thought I'd try it here. Does anyone know the frequency(ies) that make up that low rumble that you hear at the beginning of a record? I'm not actually talking about the surface noise from scratched or worn records. I've heard a lot of people say that removing the 60Hz frequency is supposed to remedy this, but honestly, I don't really notice a difference. The reason I am asking, is because I do a lot of needledrops and this low-level rumble is a bit troubling. What is the best option to removing/greatly reducing it? I use Adobe Audition to do my processing. My turntable is a Technics SL-3300 and my cartridge is a Grado M+ for mono records and also a Grado for stereo records (although the model # eludes me at the moment). Overall, it is a great program, but was wondering if there were any tools within it that would help with my issue. Thanks to anyone in advance.

 

Depends on the source of the noise.

If you look at the famous 1977 AES paper by Poul Ladegaard of Bruel & Kjaer, "Audible Effects of Mechanical Resonances in Turntables," you'll see that rumble is typically a mix of tonearm resonances and arm/cart responses to surface irregularities and motor vibration breakthrough, many of which have fundamental frequencies below the audible range but which have sidebands in the audible range and which modulate signal in the audible range. It's a complex mix of frequencies and it's not necessarily identical from arm to arm or table to table or even record to record.

Ladegaard recommends placing the fundamental arm/cart resonance much higher than we typically do -- 13-18 Hz instead of 8-10 Hz -- and to use fluid damping to minimize some of this. Also, in my experience, the better isolated the motor is from the whatever the arm is mounted to, the less motor noise breakthrough -- also, since some of that is from cogging torque, different motors and different method of motor control will produced different frequencies of vibration, and different amplitudes.

If you record some of that noise and do a spectrum analysis of it, you'll see that it's not one frequency. And because we're talking about sidebands of mechanical resonances, it's hard to filter it with a rumble filter or just by rolling off low and subsonic frequencies. The problem is best solve first mechanically with a more inert turntable.

 

Try the following in Adobe Audition: Effects > Filter and EQ > FFT Filter > Kill the Subharmonics

You can play around with the high-pass point to create a custom EQ curve.

That said, you might consider trying a different cart. I stopped needing to apply a rumble filter when I stopped using Grado carts.

 

Record surface noise is at all frequencies, no matter what speed of the record. But it gets processed through the RIAA curve.

The program DeNoise from clickrepair dot net includes two separate programs - one for general noise reduction which can be kind of touchy to use but works, and one called DeNoiseLF which greatly reduces low frequency rumble and is easy to use. It's not merely a hard cutoff filter. It basically (almost but not exactly) sums to mono the frequencies under a user-set cutoff of 20 Hz to 220 Hz, and it does additional processing to reduce remaining low frequency noise in that band but tries to keep any actual music content in that band. It won't have any effect on anything above the 20Hz to 220Hz you set. I don't think Audition can do this in any reasonable way. You can use DeNoiseLF first, and then possibly try to trickily set DeNoise to reduce anything remaining, but the DeNoise processing for this can usually be audible during song fades if you're listening for it. If you're less critical, you can get CD quality silence between tracks.

 

Thanks everyone! I was thinking of trying a new cart, and I will also try floweringtoilet's Audition suggestion. Will let you know how it goes...

 

One example of noise:
Dropbox - Tonearm mass and noise LP playback.pdf

 

Just for clairification....
2 components of sound are noise and tone.
A tone is a waveform with a shape that repeats. A noise is a series of random waveforms that don’t repeat and therefore can’t have a frequency....

Sorry, just had to be that guy!