Loudpeaker cabinet acoustic treatments

I've bought a FAST cabinet and driver set from an eBayer. Its the RS225-8/Visaton B80, 25mm MDF cabinet with 25mm ply baffle, which is not yet attached.

My plan is to have two sets of binding posts so I can have an external crossover (and use my active setup). And also, to drill the 104mm baffle hole for the B80 and also (at 45degree offset) an SB29 tweeter, so I can see how the RS225 sounds in both cases.

Now the interior of the cabinet is not treated yet. I have (mostly Monacor):
  • 3mm bitumen panels
  • 10mm high density foam panels
  • BAF wadding
  • some acoustic tiles (not actually eggshell but similar)

The volume of the cabinet (excluding driver, brace, and the enclosure for the B80) is about 21l after allowing for foam panels so I don't think I need/want 'heavy fill'.

I feel with the 25mm enclosure the bitumen might be redundant. I will probably add the 10mm foam, put the acoustic panels on top on the back, and some BAF wadding on the sides (and maybe top/bottom). Maybe a bit at the back.

Is that sane? Any other suggestions?
 
That is a closed box I assume? You can fill that pretty much up, with the acoustic foam and/or the BAF. That‘s it. Skip the bitumen and high density foam. That is pretty useless. Fill the midrange enclosure with good quality acoustic foam or use mineral wool.
 
  • 3mm bitumen panels
  • 10mm high density foam panels

Not very useful those 2. The first will exacerbate cabinet resonances (adding mass without stiffness, pushes box resonances down in frequency and decreases the Q making them more audiable.

And i am no fan of foam for damping. If ytou use foam it does not take away from the box volume, actuallty slightly increasing it.

Tease the BAF really well.

dave
 
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Is there an actual box plan for the stand mount buried in that thread somewhere?

jeff

I think the only dimensions given are - “The important external dimensions are: 10in wide baffle and 24 liter internal volume (sealed)” but there may be more details buried some where. This suggests you can play with depth and height to get the look you like. There is also the big floor standing transmission line in the first post.
 
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