VisatonLTS50coating a fullrange driver

[DrBoar]

Visaton LTS50 is a coating compound for loudspeaker cones (paper). To test if iit does anything I coated some vintage oval fullrange drivers 6" by 4"

Frequency response (Omnimic at 10 cm on axis) with one of the drivers set -5dB for clarity
Uncoated, one coat of front, one coat of front and one of the back side of the membrane. Not much going on.

I then looked at the time domain
Uncoated
Front one coat
Front one coat and back one coat

Note past 6 cycles in two ranges

Past 6 cycles in one range after front coating

Not past 6 cycles with both front and back coating

Up to 10 cycles in two ranges uncoated

That thing at 5-6 kHz dropped from 11 cycles to 8 after front coating

A further reduction

It does look like an improvement

 

[mondogenerator]

nice to see that doping works!

 

[Scottmoose]

Adding something to a cone will always change something. Whether it's actually beneficial or not is another matter entirely and will vary from driver to driver. In some cases, you may obtain a change for the better. In others, you could royally screw it up.

 

[DrBoar]

I would not dream of adding that compound to say Voxative drivers on a whim and expect an improvement
Nor my mint vintage Goodman Axiettes.

But more mundane drivers that have more or less of problem with resonances such as Philips 9710, Lowther or WR123, the worst would be that I have destroyed some decent drivers bought in a flea market

 

[mudihan]

Is there any difference between 2 coats front vs. 1 coat front and 1 coat back? Asking because the liquid seems to get absorbed by the paper cone completely, so I wonder if the side of cone makes any difference. Thanks!

 

[DrBoar]

In theory there is a difference in two oposite coats compared to a double coat on one side, how to in practice show that is an other matter.
I do not know how deep into the paper the damping compound soaks. The solvent as such may soak through but that does not mean that the solvent carry the damping particles all the way through the fibrous paper.

Currently I am out on damping compound, cheap paper drivers and time, so it might take som time to get back on this subject

 

[mudihan]

In theory there is a difference in two oposite coats compared to a double coat on one side, how to in practice show that is an other matter.
I do not know how deep into the paper the damping compound soaks. The solvent as such may soak through but that does not mean that the solvent carry the damping particles all the way through the fibrous paper.

Currently I am out on damping compound, cheap paper drivers and time, so it might take som time to get back on this subject

Thanks! Makes sense.