So Paul wrote his own software and threw out a few tantalizing tidbits about secondary resonance effects. Tom was right that tonearms/cartridges were designed to have a combined resonance that is lower than most speakers can go except for the Bass Pig. 8Hz is a good example. Amir is right that the focus of this short article (unless I'm missing some pages) is about secondary resonances. I personally don't have any woofers flapping in the breeze of resonances.
He did not throw out a few tantalizing tidbits, he has defined what parameters need to actually be measured.
You do know Paul Miller at one time was one of the leading measurement tools developer?
So I think you are doing a bit of a disservice.
Also as I mentioned another magazine does measurements that are not as detailed as the one Paul has created, however it does support a lot of what he says.
As an example in this other publication they measure g-acceleration with cartridge connected (so its cartridge-arm-mounting-etc).
On a cheap turntable with a basic cartridge this is how it measured, being very cheap it will suffer pretty badly from various vibrations and resonances.
There is a vibration at 8-12hz but it is minimal compared to what occurs at higher FR, in fact the higher FR is substantially worse than any 8-12hz vibration and this comes through on all the measurements I have checked so far.
This is probably why neither of these magazines bother going into detail about the very low resonance as it is minor in the scale of things (for a correctly setup table including very cheap ones under £200 as in this example).
Anyway this is what they say.
The simple tubular arm was inevitably lively, with a 0.45g third order bending mode at 690hz obvious in our vibration analysis.
However, the main arm tube mode at 230hz is well damped so the arm is stiff, if a little ringy.
The headshell was lively, shown in the peaks at right (5-6khz), but this is not uncommon.
And the measurements at 5-6khz is frantic (10x worse), while the main arm mode is about 50% more energy than 8-12hz
On a £14,000 complete TT, the 8-12hz vibration is identical level to the £200 one and it is minimal, with the main tube mode same value as the 8-12hz, and only a noticable (double that of the 8-12hz) narrow peak 3rd order bending mode at 450hz, showing how better engineering can manage resonances and vibrations, but has the same value at 8hz with that of the £200 TT.
I guess my point is that while there is the low level FR vibration, you should be picking up on the much higher resonances-vibrations as this are usually over 2x to 10x in magnitude and importantly be the ones that color the music.
I will keep looking to see if there is a product that actually does have a major 8-12hz vibration but so far nada, which as I mentioned may tie in with why Paul Miller and this other publication are not going out of their way for that specific 8hz characteristic.
I am curious why Bass Pig is picking up only the 8hz instead of what is happening in the higher FR and will try to find if there is anything measured that I can correlate to it (but not looking good at moment).
Thanks
Orb
I think that while I don't think that in this specific instance the de-mag makes an audible difference, there may have been problems with the protocol. My fault. But like I said, this was inserted in the middle of a session of a wholly different objective.
