SpeakerTalk

clubsport911 · Posted: Fri Oct 05, 2012 10:34 pm Post subject: BAF internal wadding

Apologies in advance if this post is in the wrong place.

I have this material in the upper and lower speaker cabinets of my 105/3's. perhaps the best at the time what recommendations would you suggest from a selection of modern days materials ?

Also, the Maidstone 109s had no internal fill in the bass section

Why ?

If I remove the fill and replace with (say) Rockwool, could you estimate the effect ?

Please move this post if it makes sense !

Thks

ColinR · Posted: Sun Oct 07, 2012 2:38 am Post subject:

Google this material

http://www.falconacoustics.co.uk/acoustic-wadding-polyester-damping-loudspeaker-cabinets-enclosures.html

(not an advert Wink

)

it's used to stuff pillows and duvets, so look towards Manchester for larger sizes and quantities.
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clubsport911 · Posted: Sun Oct 07, 2012 10:54 am Post subject:

Thanks for the lead. Having explored (at length) this whole subject of box filling materials, I'm more interested in the "ology" of the clever people using this forum who were / are still involved in speaker design.

The material shown from the link looks almost identical to what's in the cabinet right now (but of course looks can be deceiving)

I suppose the triggering event was reading the kef design concept that they didn't use any BAF wadding for the (large) bass section of the 109.

@colinr

Good riposte and well made !

proffski · Posted: Sun Oct 07, 2012 7:02 pm Post subject:

A long, long time ago we experimented with a couple of IMF Super Compacts.
It was nothing too scientific; we merely added layers of BAF wadding to the enclosure in small quantities.
The results were astounding, the apparent level of bass rose after each layer until it got to the point of being so unnatural that we removed one layer and put them back together.

Although a signal generator was available we just relied on music.
Yet on other loudspeakers the differences were either inaudible or so vague that it was a waste of time continuing with the experiment.

My 'Eminence Designer' software makes allowances for different depths of filling in loudspeakers.
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audiolabtower · VIP Contributor 500+ Joined: 06 Jan 2009 Posts: 686

Could it be that the 109 enclosure was just so big and so inert that wadding served no purpose within it's bandpass?

proffski · Posted: Sun Oct 07, 2012 7:53 pm Post subject:

clubsport911 · Posted: Sun Oct 07, 2012 9:05 pm Post subject:

@ audiolabtoower I (sort of) see your point of view, but I'd just love to know the science.

A zillion threads worth of reading of experiences leaves me none the wiser. I get the science of reducing the reflections when the system demands the woofer reaches into the midrange, but when (as in the 109) the wooder is band limited then I struggle.

I just need to read more ! [of the right books perhaps]

proffski · Posted: Sun Oct 07, 2012 9:08 pm Post subject:

"High Performance Loudspeakers" by Martin Colloms. My shelves groan with the weight of many others and I'm stiill not that much wiser!
I have sent you a sample, peek in your usual email inbox.
_________________
I contend that for a nation to try to tax itself into prosperity is like a
man standing in a bucket and trying to lift himself up by the handle.
-Winston Churchill

proffski · Posted: Sun Oct 07, 2012 9:20 pm Post subject:

Ok, 1st clue, you are dealing with a tuned reflex enclosure here not a closed box design.

2nd clue, look up adiabatic and isothermal on a good physics site.
Extrapolate before we move on... Confused

_________________
I contend that for a nation to try to tax itself into prosperity is like a
man standing in a bucket and trying to lift himself up by the handle.
-Winston Churchill

clubsport911 · Posted: Mon Oct 08, 2012 1:17 pm Post subject:

I've had a result !

I'm over in Canada on business and came upon some excellent hi-fi mags (the kind we do NOT have in the UK) and one of them is called:- Audio Express. Its basically an entire mag devoted to high end audio with DIY in mind. Smile

It's expensive as far as all the other mags go but loaded with great ideas. One section is (quite by coincidence)called:-

"Beyond The speaker Cone! - Box Stuffing and Beyond

Its a reasonably in depth article from a couple of speaker designers and helped me understand some of the science. Sure, it's not a book, but of value

@proffski - of course, the 109 was indeed a reflex design so compared to the needs of IB, I suppose the KEF bods indeed "worked it all out" deciding stuffing was not needed. Good point