Tweakers' Asylum

Posted by unclestu (A) on April 27, 2010 at 18:26:17

In Reply to: RE: fo.Q TA-102 damping material continues to amaze... posted by kenster on April 27, 2010 at 15:09:20

I have been adding dampening material to speaker cones for many decades now, but I believe the mechanism at work is not dampening per se, but the control of the nodal break up of the cone itself. Yours is in the subwoofer, but have you tried it upon your mains speakers?

For the mains speaker, I place a small piece of material, even a small piece of tape will suffice, in a vertical orientation on the speaker cone. This, in effect forces the speaker cone nodes to break up into two L/R halves and thus enhances the stereo imaging. Too large a piece and on certain very light drivers, you will definitely notice the speaker "slowing" down (Lowthers for example). But vertically aligned the three dimensionality of the system can be greatly enhanced. You can do it on the tweeter also, if yours (I believe it is) uses the tweeter with the mesh grill, A piece of 1/16 wide Scotch tape about a quarter inch long oriented vertically on the grill creates enough back pressure to dampen the aluminum cone and again split it into symmetrical halves.

By the same token, one should carefully examine the speaker to see where the voice coil leads are attached to the cone. The attachment points effectively constitute a very slight drag on the movement of the cone and creates a point from which the nodal break up will start.

On earlier Triangle speakers I notice those attachment points are oriented to the right side of the speaker cabinet. Orienting them in a vertical manner (rotating the drivers 90 degrees) again enhances the imaging quality as the entire speaker now is more L/R symmetrical.

Of course at a CES in talking to a speaker company engineer, I was laughed out of the booth when I mentioned the effects of the voice coil wire attachment. The sonic differences are there, however, and quite audible, not so much in terms of frequency response, but simply in enhanced clarity. I also did a reorientation of the drivers in a JBL TI250, their top of line speaker system way back when. That owner, who had obviously spent a huge amount of time in his set up, was dumbfounded at the difference. His wife was not so happy as we had to delay dinner in order to reorient the other side.

I've used everything from masking tape (the Scotch Blue low stick tape for those expensive drivers!) to regular Scotch tape (easy to conceal) to minute pieces of putty.

You'll notice your Alons have the voice coil wires oriented in a symmetrical vertical orientation. I used to enhance the effect by flipping the woofer upside down so that the voice coil wire attachment faced the midrange driver. That way the "dead" spot allows more sound at the crossover points to come through by lowering the cancellation between the driver, I believe.

Of course YMMV, but these are essentially cheap if not free tweaks.

Stu

Edits: 04/27/10   04/27/10