steel plates in speakers

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guydarryl
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steel plates in speakers

Unread post by guydarryl »

"Re: Goodmans Magnum K

by Andrew » Sun Jun 16, 2013 11:24 pm

Just found this link, showing the inside of a pair of Royds. It claims the plate is 4mm, so spot on Doc

http://www.audiochews.com/index.php?p=/ ... rive-units

Handy to see the size and distribution of the plates too."

I found this interesting (hope you don't my copying from your Goodmans thread Andrew), and thought the topic of steel plates in speakers may be of interest in its own right.

Questions: any ideas on the reasons for plates in speakers?
is it added mass to change resonant frequencies/modes of the cabinet walls?
is it added mass to make the speakers couple with stands better (rather like stacking bricks on top of the speaker!)?
is it something else?

I had thought that the plates would be full panel size and screwed to the internal, but the photo's in the link show relatively small plates glued (glue gun/resin?) in place.
A quick look on ebay came up with lots of sheet steel plates at reasonble prices for experimentation - although I guess that one has to be sensible and not try to make a silk purse out of a sows ear.

(I have a pair of TDL RTL2 in the study which have quite thin/flimsy cabinets whch could be interesting to try some panels in).

Guy.
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Re: steel plates in speakers

Unread post by Dr Bunsen Honeydew »

guy wrote:"Re: Goodmans Magnum K
Questions:
any ideas on the reasons for plates in speakers?
is it added mass to change resonant frequencies/modes of the cabinet walls?
is it added mass to make the speakers couple with stands better (rather like stacking bricks on top of the speaker!)?
is it something else?

I had thought that the plates would be full panel size and screwed to the internal, but the photo's in the link show relatively small plates glued (glue gun/resin?) in place.
A quick look on ebay came up with lots of sheet steel plates at reasonble prices for experimentation - although I guess that one has to be sensible and not try to make a silk purse out of a sows ear.

(I have a pair of TDL RTL2 in the study which have quite thin/flimsy cabinets whch could be interesting to try some panels in).

Guy.
Glue them in.
They should positioned centrally on the wooden cab panels and be as large as sensible.
They increase the mass and lower the resonant freq of the cab. They damp the cab without the need for foam or other mechanical filters. It is called mass damping.
For what ever reason it works, try it.

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Re: steel plates in speakers

Unread post by Dr Bunsen Honeydew »

BTW experimenting with steel plate mass damping with the mk1 Cubes back in the early 90's led me to this, and in the late 90's visiting and getting to know Joe Ackroyd I found he did the same.

Anyway you don't need it in the mk2 Cubes as the acrylic cases gives more and better mass damping than even the steel plate.

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Re: steel plates in speakers

Unread post by guydarryl »

Cheers Doc,

Does that mean that it is possible to do away with any existing foam/wool damping (or a matter of "suck it and see")?

Regards. Guy.
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Re: steel plates in speakers

Unread post by Dr Bunsen Honeydew »

Its all crap remove it and throw it away.

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Re: steel plates in speakers

Unread post by guydarryl »

:lol: love your style
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Re: steel plates in speakers

Unread post by wallace »

Well ,i hate to say it,but the Doc and Mr Ackroyd were on to something.I have just spent the day hot gluing 4mm steel plates in side my beloved JPW Mini Monitors.This has doubled the weight and the value (cost) of them.. :lol: .Quite frankly i am impressed, they sound like a different pair of speakers.Now worth at least £2000 (if reviewed by jerry).. :mrgreen: :shifty: :mrgreen: .Hurry up Guy,and let us know what you think.
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Re: steel plates in speakers

Unread post by Dr Bunsen Honeydew »

Well I thought it was funny :(

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Re: steel plates in speakers

Unread post by selby »

It's so cheap I think I'll get some for my Monitor Golds, will do tha sides, top and bottom.

A friend of mine has these solid metal, bullet shaped weights (probably 5kg) on the top of each speaker. It amazingly makes a huge difference. With my JPWs if I put a breeze block on the top the sound improves...I even blind tested it.
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But I would love a cheeky little AP10, AP20 sort of amp for a bedroom setup...

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Re: steel plates in speakers

Unread post by terrybooth »

selby wrote:.I even blind tested it.
Hopefully not when you were putting them on top of the speakers. :mrgreen:
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