Best material for new speaker cabs?

Have you guys seen the Krell's solid metal cabs, as used in LAT and master class series? Looks like alluminium to me, screwed together with hex bolts. Might be the way forward and something I'd like to commision one day. One off CNC machining has come down in price.

Not sure about alloy, but I've read that lead and concrete are the most inert.

 

Please remember one thing: Sound = energy. Any energy soaked up by massive cabinets is lost as far as sound is concerned. The first few milliwatts of amplifier output goes into exciting the mass of the structure even before any meaningful sound emerges - hence loss of detail.

 

That's as maybe, but I love massive cabinets . Also it seems pretty well accepted that the larger Tannoy drivers work best in huge cabinets, so who am I to argue....

What's more, I've got all my panels already cut up and ready to be routed, glued, screwed etc, so I ain't changing my plans now!

 

My cabs are finally nearing the end of construction - still a bit to do with additional bracing but I'm now thinking about damping materials:

I've already bought some acoustic foam but was thinking perhaps I should treat the woodwork to some bitumen based product first, and then put the foam on. I've also go a fair amount of sheeps wool I can use.

I'm already over budget so as cheap as poss!

Any suggestions?

Edit: Scratch that question, I re-read Thorstens reply from my original question and the answer to the bitumen option was already given....it's taken me such a long time to build these beggars I've already forgotten some of the things I'd learnt...Doh!

 

Here's a pic of one of the nearly finished items, driver fitted this evening. Still a bit of bracing to do and haven't put proper binding posts on yet, and the crossover is just lying around inside, but already sounding better than the Lancasters.....

 

Well done LT. Looks better than the Lancasters (I don't mean it Ian (Sideshowbob), yours still look great ).

 

Why the round edging ......? My understanding is that the flat front panel with wide diameter rounded edges eliminates defraction. But yours are standing proud so may have an effect on dispersion and reflection from the front panel [as this also will radiate sound].....still this is a bit late ! Nice looking job !

Why bass reflex ?

 

The round edging was really simply a solution to the problem of me not having the appropriate tools to cut the complex corner pieces as per the plans. My work around was to use poles instead of flush fitting semi-rectangular corners (see post #18), although they were still very tricky to rout. Yes, I guess they may have an effect on the sound, but it was round edging or nowt!

I went for bass reflex after reading around loads of similar DIY projects where people had tried various cabinet styles with Tannoy dual concentric drivers. The impression I got was that bass reflex yielded the more satisfactory results overall (not exclusively, just generally). I'm sure other possibilities could have been equally good, but I had to make a choice and this is what I went for. But hey, maybe this is only the Mk I .

 

Sorry to keep rattling on about these cabinets, but after finishing the bracing and putting in acoustic foam damping and sitting down to some critical listening, I have identified a problem. And it's a clear one .

The mids particularly are much improved, but the bass seems to be plentiful but very muddy. I was hoping to dismiss the Lancaster 'one note bass' characteristic, but I'm coming to the conclusion that maybe my new cabs are as bad, or maybe worse! Boohoo.

More bracing? Re-think the ports? Thicker damping?

 

Tannoy monitor gold enclosures

Hi
Please excuse a late reader of your speaker cabinet material query but am also interested in rehousing my vintage (I bought them in 1970) drivers.
I too like the look of the McDonald brother's design, and have available some 28mm oak that I might press into service along with some birch ply, but could not find out how to obtain the cabinet dimensions from the link that you gave. Can you help me please?

 

What did you tune the ports to in the end? If they are tuned a bit too high you can get one note bass sound.

On the other hand it could simply be your room and or positioning?

I would not worry about the edges of the round poles, the concentric nature of the driver means controlled directivity in the region where the tweeter takes over so it is unlikely to go to the edge of the cabinet.

 

Sorry, didn't see these recent posts....

Whocares - pm sent.

Tenson; after your advice on ports and tuning I downloaded winISD to have a play myself - I see what you mean about the parameters you found, the prog didn't like them all. I played around with a couple of different combinations of parameters acceptable to winISD and eventually came up with 2 vents of 4.7cm diameter length 9.26cm, to tune the ports to around 30Hz. This possibly seemed a bit more conventional going by Tannoy cabinet design and other diyers efforts.

I am finding that playing around with damping material seems to be having some positive results, I think my original efforts were a little 'thin'. The bass isn't awful, it's just loose and ill defined.

A bit of advice from elsewhere and my previous experience of various speakers I have owned tells me that the positioning of my speakers and general layout of my room is not great.....but unfortunately I don't have many options for moving stuff around (it's a family living room more than a listening room ).
It has been suggested that an equaliser of some sort is my best option for improving the situation. This may be the way to go, along with a little subtle room treatment if I can get away with it.