Thanks for the tip.The sealant appears to be silicone based and remains flexible when cured. You know, I'm thinking there's no reason to bother using my butyl sheets as this sealant will do the same job and cut down on complexity. I won't have that much mid frequency bouncing around inside as I'm only running the bass mids up to 1.5k. I bought some of the egg crate foam sheets to line the sides but I've decided instead to use 10mm wool underlay, ,built up with several layers on the back walls.
Hi Marty
I don't have any speaker building knowledge...All I've decided to do is what I thought was best to cut out freq resonance by using lead. I'm prob going to use 3M™ Viscoelastic Damping Polymers for the inside for trying to solve what I can hear when I place my ear against the cabinet...mid range sounds. There may be others who know best.
All the best Dave.
I don't have any speaker building knowledge...All I've decided to do is what I thought was best to cut out freq resonance by using lead. I'm prob going to use 3M™ Viscoelastic Damping Polymers for the inside for trying to solve what I can hear when I place my ear against the cabinet...mid range sounds. There may be others who know best.
All the best Dave.
Hi Dave, I just had a read about the 3M product. Looks very interesting. I wonder where you can buy suitable quantities for DIY speaker projects? Are you applying any damping to the baffle panels? They are taking lots of the vibrational energy from the drivers.
Cheers
Martin.
Cheers
Martin.
Hmmm. Altecs' "Voice of the Theatre" boxes which are likely as large as your Rooms were constructed of 5/8" plywood.
Material /thickness was considered Beneficial to transmit the critical sub 1000hz frequencies. thru the enclosure surfaces
FEW have issue with the sounds of those Boxes.
Double wall construction intent on Concrete rigidity reads as perhaps ott, given the teeny tiny drivers.
Material /thickness was considered Beneficial to transmit the critical sub 1000hz frequencies. thru the enclosure surfaces
FEW have issue with the sounds of those Boxes.
Double wall construction intent on Concrete rigidity reads as perhaps ott, given the teeny tiny drivers.
Attachments
The big name 'High End' domestic manufacturers make much of the importance of cabinet design & the lengths gone to in this area. I suppose it's bound to rub off a bit on us DIY ers?! When you are going to the trouble to design & build your very own speakers, the tendency will always be a bit towards OTT!
I wouldn't call these high end audiophile loudspeakers. I'm no expert but tell me why Wilson Audio build so very heavy cabinets?
I play music at concert levels and sound can be heard if i connect my ear to the cabinet wood.
Blimey, this is turning into a never ending project but there's light at the end of the tunnel!
Finally got to the stage where the cabinets are ready for the lining to be added. I'm using a half price alternative to green glue called Everbuild AC50C4 acoustic sealant to apply my lead sheet and it seems to be perfect for the job. You need much more than I expected as my 2 900cc cartridges didn't quite manage a single speaker so 3 more on the way! I'll hopefully finish the buggers in a couple of weeks and get to hear them and start tweaking!
Finally got to the stage where the cabinets are ready for the lining to be added. I'm using a half price alternative to green glue called Everbuild AC50C4 acoustic sealant to apply my lead sheet and it seems to be perfect for the job. You need much more than I expected as my 2 900cc cartridges didn't quite manage a single speaker so 3 more on the way! I'll hopefully finish the buggers in a couple of weeks and get to hear them and start tweaking!
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
As a general (industrial) rule-of-thumb, the mass of damping material should roughly match the mass of the panel it is attached too. Beware of adding too much mass, as this can dramatically reduce the panel's resonant frequency into the bass frequency range where there is far more energy available to excite the panel. The perfect panel would be infinitely stiff with infinite damping so it is unable to store energy. In the real and practical world, unless the enclosures are extremely thick and massive, then bracing will go along way to achieve stiffness, and damping will reduce energy storage. A well-known designer has stated that unbraced panel areas should not exceed 4 inches square! A mass such as a sheet of lead will have an unknown resonant frequency when floating on a thickish bed of springy silicone, and might be better more firmly attached to the walls.
Cheers, Carl.
Cheers, Carl.
The lead is now all installed & the acoustic sealant layer has had 2 weeks to set. I'd say it's less viscous than plastecine but still slightly unset and deformable. Under finger pressure. I've installed the carpet underlay damping (30mm on back panel, 10mm on sides, top & bottom. Knuckle rap sounds very dead indeed & there's still the baffle to go on which should hopefully increase overall solidity.
An externally hosted image should be here but it was not working when we last tested it.
I'm hoping the end result will be inert and resonance free in its pass band. It will definitely be my best (first) effort!
Martin.
- Status
- Not open for further replies.