Any physical tweaks to increase roll-off of woofer?

[ChuckT]

Just wonder if there are other ways to increase the roll-off of a mid/bass, I don't mean increasing the order of filters but physical tweaks such as damping the cone or just the dust cap. I have a SS 8530 and I would like smooth out the region above 5K .
Thanks.

[octopus]

Only thing I can think of is dampening a metal basket to take away the ring sound...

[Nat Eddy]

Mass loading with mortite or some other putty at the apex of the cone, or around the dust cap might work, but it will change other parameters in addition to upper end roll off. But it is a relatively reversible tweak, so it might be worth trying. But don't use an oily putty on a paper cone, and don't press it in so hard you can't get it off until you are certain you want to keep it there.

[SY]

Do you mean HF rolloff? And by "increase in the rolloff," do you mean a decrease in the rolloff frequency?

[mrfeedback]

I would like smooth out the region above 5K .

A zobel network can work wonders here.

Eric.

[SY]

Hmmm, I dunno, Eric. If it's a matter of cone breakup, then doing an RC may be a bandage on a corpse. Cone breakup can be sometimes ameliorated with cone dope or varnish, but it's often a function of the boundary conditions at the surround attach. If that's the case, all you're left with is rolling off steeply well below that breakup, because the cone dope will just lower the frequency of the problem rather than curing it..

[mrfeedback]

Hi Sy,
The dome is very often the source of nasties ime.
Damping the dome by painting with PVA woodglue has worked for me, as has soaking thinned PVA into the cone.

IME a zobel network across the driver directly at the driver connections can quite dramatically reduce HF nasties and enable a rather smoother and more tolerable response from typical woofers.
A zobel network is effectively a snubber network that loads the driver generator output under overshoot conditions and reduces the ringing time of the woofer as I hear it.

Eric.

Did you get those Wolf Blass photos ?.

[SY]

Yes, I did. I've asked a couple guys to contact you. Thanks!

We now return you to diyAudio.

[mrfeedback]

The photo is for those who are wondering what Sy and I are talking about.
Sy, tell them to email me is best - I am out and about lately and my mobile has fritzed itself.

Thanks and Regards,
Eric.

[ChuckT]

Mmm.. Wolf Blass! I believe intake of one bottle should roll off the high pretty well for me. No, I must look for other means.

I tried an overdamped zobel using 8.2uf/10ohm, but still doesn't do well in the 6-8K region, maybe I should increase the cap and lower the resistance, any ideas?