[Ericus Rex]

I, too, have used Luckydog's equation for measuring effective mass of arms.  I would be very interested to see if Wayner's easier approach to measuring would result in a close figure to Luckydog's.  I'd say if the numbers are within .5gr then Wayner's approach is good enough and wouldn't require any Advil afterwards...unless you broke your stylus in the process.

[TheChairGuy]

My concern in all of this though, is how much of an audible effect Resonant Frequency matching really has and if we convince ourselves that 10Hz is the magic number, how much we  might restrict cartridge choice because of this.

I've read many posts where 10Hz is sought as some form of Holy Grail - I think we do need to put this in some form of balance.

Personally I don't believe I had any audible issues with either of these carts while playing music (as opposed to test discs).
Both performed admirably at their respective price points, and I did'nt feel it necessary to apply any form of resistive loading mods to adjust their tonal characters.

Cheers
Dave

Dave - that's mostly been my experience, too.  Then again, I've never purposely paired a high compliance cartridge in the past 6 years since my return to vinyl (when I more thoroughly understood the subject) with, say, a heavy tonearm (to my knowledge)...so maybe I've self-audited myself before finding out any wrong effects.

I throw the subject into the same bin as getting 'perfect' alignment points.  It's too elusive of a goal and, ultimately, is decided anyhow on how it sounds - not how it measures.  Overall, it's nuanced stuff - not the meat of the vinyl matter.  Generally, close enough with both subjects, is really good enough. 

For compliance, I find a nice pot of silicone goo does wonders for tempering all sorts of resonance mismatches between cartridge and tonearm.  I've experienced damping via selector from JVC (both oil and electronic), at the pivot (JELCO / Audioquest) and spring/rubber at the counterweight (DUAL 701)...and found those damping methods inferior in effect to a nice pot of silicone goo sitting outside the tonearm with a paddle sitting in it square to be the best (KAB, my home brew solution I created a few years ago with aluminum foil, or the perhaps the best concepts are those arranged by Well-Tempered and Townshend)

As David / dlaloum points out....damping of this sort generally works best for the low frequencies (or perhaps ONLY at the lower frequencies?).  But, as the effects of compliance mismatch are generally in the low frequencies (actually subsonic) that we are experiencing...silicone does the trick for matching cartridge to tonearm quite well.

So, I hope you don't get blasted into the weeds on this from certain quarters, as these are my experiences, too

John

[bastlnut]

hallo,

yes, silicon is a good equalizer. it also damps and i am not a fan of damping.
i prefer to find the right tonearm for the cartridge, or use another cartridge that works better with the tonearm that i am using.
measuring eff. mass with simply measuring and doing the math does not tell the whole picture,
just as knowing the published specs will not get you a match.
there are tweaks to be used to get a cartridge to behave better.
even what you place the whole turntable on makes a difference....take the example of woofer pumping because of proximity to speakers or using an unstable table to place the turntable on.
i think that many of the formulas we use for calculating system resonance are just simple and meant to get us into the ballpark.
the tweaking that we do after is much more conclusive in determining if the sound is a hit or a miss.

damping can take the life out of the music just like using a heavy tonearm with a high compliance cartridge.
so it can be said that the weight of the tonearm overdamps the cartridge.
a unipivot tonearm does well being damped otherwise it will not provide enough of a reference point for the cantilever to move from to create the signal.
add too much silicon to the pot, and the life gets sucked out of the music.
a gimbal tonearm has more friction than a unipivot so is damped as a result, the movement is like adding silicon to a unipivot damping pot.
compliance does not tell the whole story of how the cartridge will react.
take for example the Denon DL-S1 that i reviewed a while ago.
the cu value suggested a lighter tonearm, but it ended up that a 13g-14g tonearm offered the best match for sound quality.
further loading the cartridge properly made additional differences in SQ.
loading at a lower value sounded better with a lighter tonearm, but really locked in and sounded best at the higher value and the heavier tonearm.
it was also louder and resulted that i did not need to turn the volume knob so far to the right for the same volume in room.

some tonearms feel lighter in use than others, and this has no relation to whether the tonearm has a high eff. mass or a low eff. mass.
the question for me is....how much damping do i need to help the cartirdge with.

regards,
bas

[dlaloum]

the question for me is....how much damping do i need to help the cartirdge with.

Amen to that

How does one determine the right amount of damping.... and perhaps the right type?

There is the compliance related LF damping (oil/silicon, servo or friction)

But there is also the Mid to HF damping provided by damping internal to the arm tube, damping shimms, herbies tonearm dampers, wrapping tonearm in tape etc...

is there any way to tell what form of damping might be helpful, and then how much is the right amount - to avoid overdamping....?

bye for now

David

[DaveyW]

So, I hope you don't get blasted into the weeds on this from certain quarters, as these are my experiences, too

John

Spoilsports!

Seriously though it's a good debate and very interesting to get everyone's varied perspectives.
Cheers
Dave

[dlaloum]

I have to say, I have read repeated reports of theoretically non-ideal combinations sounding good (or even great)...

It is not clear to me whether there were mitigating circumstances (damping?), isolated platform? Other?

Some things I keep hearing:
1) Higher compliance designs being silky smooth, grain free, controlled but in a velvet glove...
2) Lower compliance designs being more punchy, dynamic, full of energy, having bite...

This is purely in reading MM/MI reviews from various audiophiles - and usually higher end classic models (Signets, Empires, ADC's, AT's)

I'm not ready to commit myself to an opinion yet... but I will in due course...

Another area of substantial FUD (Fear, Uncertainty and Doubt) - is the headshell and its impact on sound....- which I believe has a relationship with compliance and tonearm mass/design...
High compliance provide less energy back into the arm to be dissipated, low compliance more - low compliance then use some of their mass budget in putting more damping into heavier headshells and tonearm damping....(talking mostly about mid/high frequency damping in this case)

Could it be that light flexible headshells suit very high compliance cartridges (after all some very well regarded tonearms were intentionally designed to flex as a damping mechanism...eg: NAD) - where heavy rigid highly damped headshells are best for low compliance (mostly MC's)?

[Wayner]

I like putting a small dot of plasticlay directly on the arm tube near the arm clamp area, or about 2 inches this side of the pivot bearings. Some experimenting is in order here, and I agree with bas's comment about sucking the life out of the cartridge/arm with too much damping. Just enough to take the ringing out of the tone arm tube is the trick.

 

I have noticed more ambiance in the recordings using this technique, and now I have the dot on all of my arms.
Wayner

[bastlnut]

hallo,

how does one determine the amount of damping needed....
this could take a whole book to explain, and then there will still be questions.

it does start with the amount that the bearings offer, what the armwand offers....
and so on and so on.
i don't agree with your assessments of what affects which frequency....
it is much more like one needing to identify where the damping starts and remember that it will trail off in both directions as to its effect.
silicon damping works like this, but bearing friction affects the frequency extremes more than anything.
even the geometry and type of bearings have its effect.
for example, when a record is pressed off center, not only do we hear WOW but also  exaggerated upper mids....SME tonearms are the biggest sinners here.
warped records tend to sound bright and have thin bass, here Linn arms are very susceptible.
using ball races for all the bearings have its woes.

i think it is more the construction of the tonearm that addresses these issues and offers better damping than our tweaks.
there are just more issues with the less developed and lesser cost tonearms.
some makers add damping to compensate for the shortfalls in design or because they are just adapting an old design and do not want to start from scratch....which is costly.

we are off on a whole new tangent here that deserves its own thread,
but tonearm designers are not apt to share their secrets.
i will think about what is of more use for normal Otto turntable user and post again.

sorry if it seems like a rant, it is not.
it is not so easy a question to answer.

regards,
bas

[BaMorin]

I like putting a small dot of plasticlay directly on the arm tube near the arm clamp area, or about 2 inches this side of the pivot bearings. Some experimenting is in order here, and I agree with bas's comment about sucking the life out of the cartridge/arm with too much damping. Just enough to take the ringing out of the tone arm tube is the trick.

 

I have noticed more ambiance in the recordings using this technique, and now I have the dot on all of my arms.
Wayner

Wayner, do you play guitar?

[Wayner]

Yes.

 

[BaMorin]

Yes.

 

Good............because it's easier to explain concepts using other known common devices.

The strings on your guitar when only touched....at certain frets will create harmonics. The lowest of these in pitch vs the open string is the 12th fret. Then 7th/19th fret then 5th fret.  The 12th fret is half way between the two termination points of the string. Nut and Bridge(saddle). Touching the string at the 5th and 7th fret will cancel almost all string sound (resonance).
Using the guitar neck as an example of distance.......and considering the stylus location as the saddle, and the bearing as the nut. You can put some damping material at the distances figured by ratio at the 19th, 7th, and 5th.

When i modify AR XA/XB arms I use a piece of foam ear plugs at those spots internally (as they try to expand and keep pressure applied)  It does wonders.  You might experiment with the material you are using at those three points and see if you get improvement.  The idea of damping is to stop resonances that interfer with termination.  A unipivot in design of the pivot just about cannot lose termination at that point, you can still lose termination at the stylus though. An arm such as a Linn has a total of 10 points at the vertical pivot that can lose termination (bearing chatter) The chatter has to start due to the arm tube resonances......eliminate the odd order harmonics.

[Ericus Rex]

Good............because it's easier to explain concepts using other known common devices.

The strings on your guitar when only touched....at certain frets will create harmonics. The lowest of these in pitch vs the open string is the 12th fret. Then 7th/19th fret then 5th fret.  The 12th fret is half way between the two termination points of the string. Nut and Bridge(saddle). Touching the string at the 5th and 7th fret will cancel almost all string sound (resonance).
Using the guitar neck as an example of distance.......and considering the stylus location as the saddle, and the bearing as the nut. You can put some damping material at the distances figured by ratio at the 19th, 7th, and 5th.

When i modify AR XA/XB arms I use a piece of foam ear plugs at those spots internally (as they try to expand and keep pressure applied)  It does wonders.  You might experiment with the material you are using at those three points and see if you get improvement.  The idea of damping is to stop resonances that interfer with termination.  A unipivot in design of the pivot just about cannot lose termination at that point, you can still lose termination at the stylus though. An arm such as a Linn has a total of 10 points at the vertical pivot that can lose termination (bearing chatter) The chatter has to start due to the arm tube resonances......eliminate the odd order harmonics.

Brilliant explanation!  Thank you!   

[TheChairGuy]

Foam ear plugs inside the arm tubes to break up arm tube resonances - quite cheap and trick, Bammer; thanks for that mind stimulant

[BaMorin]

Foam ear plugs inside the arm tubes to break up arm tube resonances - quite cheap and trick, Bammer; thanks for that mind stimulant

Also, on the box they come in usually lists attenuation vs frequency

125hz down 33.9db
250 down 37.7
500 down 39.8
1000 down 38.5
2000 down 37
3150 down 41.9
4000 down 42.7
6300 down 45.5
6800 down 44.6

And if ya wanna get real fancy, a thin coating of rubber cement inside the arm tube. Beats the heck out of wool and won't hold a static charge   

[Wayner]

The arm tube is not like a guitar, it doesn't have multiple strings, stretch from one end to another. It's more like a pole. In my experiences with lighting standards (light poles), they would vibrate themselves to death, because of their length, wind speed and wind load. We invented pole dampers that when set in the proper position, stopped even order harmonics, not some of them, but all of them. Odd order went away, as there was not as many wave lengths to become sympathetic with. The even ones could chum up easily, because 2 goes into 4 goes into 8 etc.

This is my approach. Do I think it works? Yes. I can't prove it with measurement, but my ears tell me the sound stage has gotten larger, the subdued details like ambiance, reverb and the like are more present. This tells me that nasty wave canceling elements are being muted, allowing these small details to come thru.

Wayner

[dlaloum]

So any calculations as to the optimum spot for plasticene dots?
And how does this change with differing tonearm lengths and shapes? (J, S, Straight.... tube, tapered, etc...)

Or is it (like so many things in this hobby) trial and error, suck it and see.... or rather: try it and listen, then again, and again, and again, and again......(starting to sound like a "broken" record.... - I wonder how long sayings like this will survive in our ever more digital world)

bye for now

David

[neobop]

I think that having a reasonable cart/arm resonance will just make it easier to address damping as a separate issue. All this stuff is interrelated and it's sometimes hard to figure out exactly what's doing what. But if say, you're not using the damping feature on a Jelco 750 to run a 50cu cart, it will be easier to make changes and/or access results.

I think the end result could probably be seen with the output on an oscilloscope. Overshoot vs slower transients vs neither. That's at least from the cart end of things pertaining to cu and mass. The rest is really structural considerations and fixes. A silicone type unipivot (some don't have silicone) provides damping as part of the design. It would only go beyond optimal damping when too much drag is created at the bearing. This would also be seen as slowed transients. You don't need an oscilloscope to hear this with really high quality equipment, but it helps. Many of us are using dots or foam inserts etc, to damp the arm tube. Origin Live cuts slots in a RB250 so ringing or vibrations can't complete a cycle around the tube. So how do we sort out bearings, arm tubes and all the rest from cu/arm mass? I think vibrations or bearing issues can sound very similar.

Cool dog heh?
neo

[BaMorin]

The arm tube is not like a guitar, it doesn't have multiple strings, stretch from one end to another. It's more like a pole. In my experiences with lighting standards (light poles), they would vibrate themselves to death, because of their length, wind speed and wind load. We invented pole dampers that when set in the proper position, stopped even order harmonics, not some of them, but all of them. Odd order went away, as there was not as many wave lengths to become sympathetic with. The even ones could chum up easily, because 2 goes into 4 goes into 8 etc.

This is my approach. Do I think it works? Yes. I can't prove it with measurement, but my ears tell me the sound stage has gotten larger, the subdued details like ambiance, reverb and the like are more present. This tells me that nasty wave canceling elements are being muted, allowing these small details to come thru.

Wayner

Well, yes and no..........the example you gave was for a pole (pipe) only terminated at one end to begin with. a tonearm/cart should be terminated at both ends......the resonance causes un-termination.

The example I gave was for nodes along a "pipe/beam" that is terminated at both ends.  Those nodes are dependent upon length between points of termination.  There are exactly the same points in relation to distance from the 12th fret in to the saddle. if you halve that distance again, the ratio of distance remains the same.
It doesn't matter the type of pipe.......this is a simple mechanical model.

[BaMorin]

So any calculations as to the optimum spot for plasticene dots?
And how does this change with differing tonearm lengths and shapes? (J, S, Straight.... tube, tapered, etc...)

Or is it (like so many things in this hobby) trial and error, suck it and see.... or rather: try it and listen, then again, and again, and again, and again......(starting to sound like a "broken" record.... - I wonder how long sayings like this will survive in our ever more digital world)

bye for now

David

Shape isn't an issue.........it's a function of distance. The shape can and does affect amplitude. Taper affects fundamental tone.

[dlaloum]

OK.... just thinking about this...

with an oscilloscope, measuring either square wave or sine wave cartridge output.... or some impulse tests perhaps...

Would I therefore be better off turning the tonearm damping off... adjusting it for best results, and then turning the damping back on? (possibly even at a lower level)