Confused about compliance matching with airbearing


Chrome doesn't let me post more than a paragraph, so let's try again.

I am ordering a Soundsmith Voice. I currently use a 20cu Grado with no issues, 10hz vertical resonance, on an MG1 airbearing.

Petere advised against the 28cu model which confuses me because Trans-Fi owners are use 32cu carts with what seems to be much more lateral mass.

Should the horizontal effective mass be high in order to use high compliance?

"Keeping the wand short reduces resonances within the arm which typically colours the music. It is probably one of the major influences contributing to the overall sound of a tonearm. Manufacturers of conventional pivoted arms go to great lengths to try to eliminate resonances. They have a hard job!
Together with a lightweight slider, Terminator has the lowest lateral inertia of ANY airbearing tonearm on the market weighing in at just over 80g including the saddle, counterweight & cartridge, allowing safe tracking of the fussiest high compliant cartridge."
doctorcilantro
The horizontal resonance will be considerably lower, because of the higher mass. The ET-2 specs are 7g vertical, 25-35g horizontal effective mass(in horizontal plane, effective is actual, given lack of a pivot). This has a fortunate effect,in that horizontal is mono info, and deep bass is mixed to mono; the greater inertia enables higher output(the cartridge is shifted less, thus greater displacement of cantilever with respect to the cartridge windings). And, since warps are vertical, there's no penalty in that regard. Off center spindle holes, however..

In practice, I've found the loading of the cantilever suspension by horizontal mass does effect the over-all sound- too high, and it's like being off level(the stage in one channel collapses-same effect as with maladjusted anti-skate) in both channels. This is obviously cartridge compliance dependent. I use an ATOC-9 in an ET-2, and minimize the horizontal mass by putting the counterweight at the extreme end of the beam, thus using as little mass as possible. Using the Shure test record, I noted resonance at 9HZ only(range on the record is 5-14 HZ). If I use the dynamic compliance spec for the cartridge(9 cu), I calculate close to that for horizontal resonance(9.235 HZ @33g,25g plus 8g cartridge ). Vertical resonance calculates as 14.71HZ with 5g effective mass vertically(this is suggested by ET-2 manual as value, not 7g, why I don't know). I have no tracking issues, even with off center lps, stage is huge, but I do note tight coupling of lp to platter is needed to produce satisfactory dynamics; greater mass would yield more, but at a price I don't want to pay.
The ET2 is quite low mass then. I'm at about 60grams with cart, counterweight, and entire arm assembly on the MG1.
Rcthweatt, The ET manual is a well-spring of technical information, but I am confused on the subject of horizontal mass. If I understand correctly, moving horizontal mass is 25-35gm wand+manifold, plus up to 40gms counterweights, plus optional 18gm damping trough.
Yeah, I do think the counterweight was overlooked. The damping trough is attached to the horizontal moving mass asemmbly....interesting.
Dgarretson, Drcilantro-

Ooops! You are correct, as p.5 indicates, spindle 14g,arm tube 11g, so 25g w/o CWs, which are 5 &15g, small and large. I assume the spindle weight includes the CW arm, and the clamp, post, etc. (I'm not disassembling to weigh it tonight!)including the lead piece which slides into the clamp. So, my horizontal mass would be 25+5(1 small weight)+8(cart)+1(screws, also neglected),39g;using 9 cu, 8.49HZ,which still agrees pretty closely with test record. Now- this cu figure is at 100HZ,which isn't the frequency we're at, 10 HZ would be better, so supposedly one should multiply this by 1.5-2,or halve the static figure(35); trouble is, using these I get 6-6.9HZ: at those frequencies, arm is perfectly stable. Hmmm...not horizontal, but vertical resonance? 7+8+1g times 18cu(.000018), I get 9.378HZ, also close. Way to settle- add mass, and see if 2 resonance points develop..unless there's a test record with a wider range?