Arm resonance and other questions..

I am planning to listen to CDs through some rake and gravel noise to see just how good or bad CDs can sound. Face it, an LP is a mechanical device and if the groove is gone, it's gone. You can clean it, wet dry, chemicals no chemicals, 'till the cows come home, it will always sound like drek. Now, if you are single-minded enough to say you can listen to, and actually enjoy, the sound coming through this, you deserve the PBB Analogue Achievement Award. Nobody said the road to vinyl/analogue Nirvana would be easy.

The arm does resonante with the energy fed back into it from the cartridge. This happens with any arm, but it is not a great thing. A little damping can help, especially at the headshell. Try some self stick felt on the headshell and on the sides of the cartridge itself. Not alot of it. This worked for me.

As for the Brubeck album, it's trashed. The sound of the grinding getting louder and softer with the music, is the tipoff. Played on a "vinyl lathe" as I call it. Nothing can be done about it.

That's very perceptive of you to notice that.
Whenever I hear a description of a turntable functioning I get excited and giddy. I go into this sort of change, everything else seems not to exist and time stays still. I think it is because with every single element of function that a turntable does, there is a way to get evan more fidelity out of what is already the highest fidelity known. To hear elements of performances of the greatest musicians known to man, To realize artifacts of sonics that reveal the humanity of talent that evan possibly was not noticed during the origional performance. To transmit information through sound that was never heard, or thought could be, laying bare the souls of poeple the transcend sound into a living, breathing, piece of emotional history of passion, exitement, soul!
Anyway, you have my curiousity. It is normal for an arm to carry resonences from the cartridge, in fact, it is desirable for the arm to transfer energy from this back through the arm and away. But I have never heard an arm be louder at the bearing than the cartridge. Usually, when these ideals are met more the cartridge actually gets softer sounding. (thats what I have perceived). I am curious as to whether my rb-300 will do the same thing, as I have never thought to listen to this on it.
I wonder, could it be the coil spring that controls the trackong force resonating? Could it be that energy is being trapped at the bearing because it is not being absorbed by the plinth? Could it be soundwaves escaping from inside the armtube and that is the easiest place to hear it?
Whether or not these are true does not nessesarily mean that there is something wrong with your arm, though, so don't misunderstand my thoughts. I would not take it as something that must be alleviated. (provided everything is sounding the way you think it should). Luckily, some things that might alleviate it are things that you would want to do anyway, like the heavier counterweight, which will change the spring pressure, adjust or experiment with the tightness of the mount, stuff the arm with foam, and last but not least, the HIFI mod, which I have tried and found to be worthwhile. Contact the very same TWL above. (TWL, aren't you curious as to what your HIFI would do for his desribed condition?, anyway, if I were in his shoes, thats what I would do).

Thanks for the replies. sorry i haven't responded sooner but I've been out of town.
Hearing the amount of resonance in the arm it makes me wonder what would happen if the arm was completely dead (resonance wise). Im assuming that a cartridge is designed so that it dose not move and only the stylus moves, thus only receiving info from the groove and not the arm, bearings, plinth ect...?? If the arm is vibrating enough to here it, this must shake the cartridge at the same frequencies possibly conflicting with the same or other frequencies being picked up by the cartridge. Please correct me if im wrong! Would a sonically dead arm be a step forward or back?
(TWL) Following the thread on your “HIFI” mod my first thought was...... “well Duh”....that's a no brainier!!...Why didn't i think of that... Simple, elegant, cheep .... at least until you market it! ; ‘ ) and logical. Hats off to you and your ingenuity. Here is a question .... If i have the basic idea right, its all about increasing the moment of inertia in the lateral plane? Thus keeping the cartridge steadier and more resistance to groove influenced vibration, leaving the stylus to “wiggle” in a stable housing. All this insuring a more accurate picture of what is in the groove. Now what happens when the cartridge is “sinning” from arm resonance??. This has been on my mind for the last few weeks and i need help getting it out ... Im bet you have all done it before but go and put on a lp with a loud and complex passage ... turn off the sound and listen to that arm sing!!! Considering the lengths people go to eliminate the most subtle vibrations in the table/system this thing is just screaming with un controlled vibes!!
As for my Brubeck lp i’m going to learn to listen threw the groove noise with the idea that in time i will not here it any longer. If i can get to this point with this album then i will never need to clean another record as long as i live!!! ; ‘ )

Bill.......

Bill, there is a fine line in the amount of damping that should be done on an arm. If you do too much, it sounds dead. I recommend starting at the headshell, and even the cartridge. I used some self-stick black felt from Wal-Mart. I cut some very small pieces, and stuck them to the sides of the cart, and on the headshell. On the Rega arm, the finger lift is quite lively, so it should be damped. Also a 1/2" wide ring of felt around the arm about 1/3 of the way out from the pivot is a good start. This 1/3 point is the "ring" point on the Rega arms. That is about all you'll need, and you might not need even that much. You'll know if you do too much, because it will start to sound dead. I highly recommend doing the HiFi mod. The other really great mod, is the HeavyWeight counterweight from Expressimo Audio. A world of improvement for only $90. You can make the HiFi mod yourself by following the directions on my thread. You will not believe the improvements from that!

Yes, it is all about lateral movement control. And yes, a singing arm is not good, but as I said, you can go too far. I don't know the exact reasons, but some "liveliness" in the arm is good for sound.