Slight 100Hz Buzz from a Rogers LS7 Speaker Cone - Simple Fix/Recone?

[dantheman91]

Hi

Been offered a pair of LS7's and want to go back to them for nostalgia but their is a problem with one of the speaker cones with a slight Buzz at 100Hz could it be remedied by rotating 180 Degrees , Simple fix or Recone - thoughts much appreciated?

Cheers
Dan

[Barry]

Do you mean there is a resonance at 100Hz? Or could it be there is a problem with the amplifier driving it?

[walpurgis]

How do you know the buzz is at 100Hz?

Rotating the driver is unlikely to help on a speaker with lightish cones. However, if the voicecoil is undamaged, the cause of the buzz may just be slight misalignment making it foul in the magnet gap.

It's quite possible one of my 'cures' would work. See here: https://theartofsound.net/forum/showthread.php?51367-The-walpurgis-fix-for-buzzing-and-rubbing-speakers!

[dantheman91]

Do you mean there is a resonance at 100Hz? Or could it be there is a problem with the amplifier driving it?

Could possibly be an amp fault but they have been tested by an engineer who said the driver had a fault at 100Hz could well be an amp fault .�� could also be resonance. ��

[dantheman91]

How do you know the buzz is at 100Hz?

Rotating the driver is unlikely to help on a speaker with lightish cones. However, if the voicecoil is undamaged, the cause of the buzz may just be slight misalignment making it foul in the magnet gap.

It's quite possible one of my 'cures' would work. See here: https://theartofsound.net/forum/showthread.php?51367-The-walpurgis-fix-for-buzzing-and-rubbing-speakers!

I don't know but the guy who owns them now has had them tested by an engineer who said one driver has 100Hz fault but could well be resonance or faulty amp their end.��

[graham67]

May or may not be relevant but I had a pair of Studio 1s that developed a buzz at low frequencies. It was caused by cone sag causing the cone to rub. If I gently pushed the cone in with my fingers , I could hear the cone scraping.

It was not fixed by rotating the driver so I ended up sourcing replacement drivers.

[walpurgis]

The cone does not rub against the coil.

Suspension sagging can make the coil foul the magnet gap and cause the rubbing. This can often be fixed by realigning the rear cone suspension spider. I can advise on doing this.

[graham67]

Thanks for correcting this Geoff, original post now amended to avoid confusing future readers. ��

[Lawrence001]

Edward told me a simple fix that has worked for me a couple of times. Gently push the driver in a few times and you should feel the rubbing. Keep pushing in and out gently for a minute. Keep the motion almost parallel with the voice coil gap so as not to distort anything but you can tilt at a slight angle of you have sensed the side where the issue is. It can disintegrate any foreign body that might have got in there, or rub a bit of overheated varnish off the coil itself.

Try the speaker after a minute and if the rubbing noise has reduced do it again. Worked for me as I said!

Sent from my POT-LX1 using Tapatalk

[dantheman91]

So another pair of LS7's are on the way...:):)

Will get my engineer to fully test them when they arrive...

[dantheman91]

They are here I can see no issues they work fine no cone scraping under pressure took a fair amount of volume on test all good I heard no buzz . Going in for a a test on scope later on.�� just to be sure.

[dantheman91]

All Tested and the cone surround needs gluing on the problem cone no other issues units working fine otherwise - which would be best to use with polypropylene cone?

[Pharos]

I've used Thixofix on Polyprop.