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acoustical stuffing / sound dampening subwoofer cabinet REL BRITANNIA B1 subwoofer

Hello,

 

Quick question on acoustical stuffing / sound dampening in a subwoofer cabinet.

I am the 2nd owner of a REL Brittania B1 subwoofer.

Opened it up, and NO stuffing. A bit surprising. My guess is the original who was a dumb &*(&#$   removed it.

I am guessing there should be some stuffing in the cabinet.

 

IF SO, I am looking for recommendations as to how much to put in the cabinet and where.

THANKS for the help!

Please see pictures for view of interior of cabinet. Bottom-Middle- Top pictures

 

FYI--- Interior of cabinet is approximately 13” x 15” x 19”

 

 https://drive.google.com/open?id=0B01U3HhYR3nZZUJ6U0lzZVNMYkE

https://drive.google.com/open?id=0B01U3HhYR3nZbGZNR1ktRHBOMmM

https://drive.google.com/open?id=0B01U3HhYR3nZS3kzSWpOaF9ySmM

REL BRITANNIA B1


stevethe4th
erik_squires
16,022 posts
 
Keep in mind that adding/removing stuffing also affects the tuning of the cabinet. That cabinet looks REALLY clean, so not sure it ever had any. Stuffing will raise the effective volume, lowering the Q and lowering the tuning frequency. This Another way to put it is it will damp the response at the bottom.

Also, woofers get hot. The more stuffing, the hotter they will get and the more compression, I’m not entirely sure this cabinet ever had any stuffing at all, it looks way too clean. I would reach out to REL and ask if it used any first.

If you decide to add fill, Acousta-Stuff is a pretty good fill but for damping panels I much prefer the multi-layer Sonic Barrier to any thin membrane stuff. Comes with PSA already applied. I would start by playing music and feeling the cabinet for resonances. Apply the thickest possible Sonic Barrier there.

Then, if appropriate, lightly fill the cabinet. Make sure you do not insulate any hot areas such as internal heat sinks, metal surfaces, and leave room around the woofer for it to breathe. Woofers get hot when used, the better cooling, the less compression.

Best,

E
audiokinesis
2,734 posts
 

"Stuffing will raise the effective volume..."

Well, imo, yes and no.  Stuffing will increase system damping, but the measurements I've seen, and the professional-level modeling programs I use, indicate that its effect on low frequency extension is insignificant.  So we can't buy "free bass extension" by adding just the right amount of our favorite stuffing material. 

Ime the slight softening of "impact" from adding stuffing to a subwoofer usually outweighs any benefits (assuming the system is well designed to begin with), BUT not necessarily... 

For example, in a situation where room + sub = boomy, aggressive stuffing of the cabinet can be a net benefit. 

If it's a ported box in our "room + sub = boomy" scenario, often we can make a greater net improvement by lowering the port tuning frequency, which may call for some ingenuity.

Duke

geoffkait's avatar
geoffkait
23,365 posts
 
Almost all speakers have too much stuffing. More than say a grapefruit size amount strangles the sound and muffles the bass. I know what you're thinking, "but everyone does it."
erik_squires
16,022 posts
 
I think that evaluating stuffing without the proper experience with microphone techniques is pretty inefficient.

I point you to this thread:

http://techtalk.parts-express.com/forum/tech-talk-forum/8948-effect-of-stuffing-on-the-qtc-in-a-woof...

bdp24's avatar
bdp24
9,756 posts
 

As auxinput states, internal bracing is the best and first way to combat enclosure resonance. Braces stiffen the enclosure walls, raising their resonant frequency above the frequencies the sub is asked to produce. Internal stuffing "tricks" the box into thinking it’s internal volume is greater than it actually is (by slowing down the sound), and needs to be matched to the driver’s needs in relation to that volume. Both too much or too little for any given application are possible.

Sonic Barrier is a fair enclosure wall damper, but a superior product to achieve that end is NoRez, sold on the GR Research website.

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