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Random Idea: Aluminum Baffle Heatsink?

Discussion in 'Amps and Cabs [BG]' started by voided3, Oct 27, 2018.


  1. voided3

    voided3

    Nov 11, 2008
    Random Idea: I see a few manufacturers over the years have offered aluminum speaker enclosures, for example GK (for bass) and Bogner (for guitar). I wonder if anyone has experimented with making a cabinet with an finned aluminum baffle board for heat dissipation purposes, similar to some automotive differential covers for oil cooling? Perhaps even going to the next step and putting heatsink compound in lieu of a traditional speaker gasket and then mounting it with T-nuts for a solid mechanical bond.

    My presumption is it’s not economically feasible or capable of efficiently dissipating heat as much as a heatsink directly on the driver’s magnet structure surrounding the coil. Either that or perhaps it wouldn’t make any difference for applications outside of super high powered subwoofers.

    What triggered this idea was a recent loud gig where I noticed my sealed Ampeg 4x10 at the end of the night was actually warm to the touch near the top of the grille from heat radiating off of the drivers. Being sealed, it doesn’t have ports to allow convection cooling, so the heatsink idea popped into my head. Maybe they just needed to turn up the air conditioning in the room. :D

    I’m just thinking out loud here. Thoughts?
     
  2. What sort of lighting was on stage?
    Thinking a lot of large incandescence lamps could contribute to cab being warm?
    You know, like heat warming lamps in a buffet line?
     
    saabfender likes this.
  3. voided3

    voided3

    Nov 11, 2008
    Just some LED light bars on each far end of the stage, not near the amp. It was an indoor wedding gig, but the windows and doors were open to the outside and it was a fairly cool evening. The heat definitely was from the cab as the grille was room temperature at the bottom but warm at the top. I was running a Mesa D800+ mounted in a rack so the heat definitely wasn’t from the amp’s exhaust, either.
     
    Old Garage-Bander likes this.
  4. JimChjones

    JimChjones

    Aug 6, 2017
    SE England
    Well, if folk are genuinely chucking hundreds of watts into their speaker cabinets then that energy has got to go somewhere. Whether the cab interior gets warm enough for it to affect the drivers I don't know I'm afraid.

    Transferring heat through the basket into the baffle feels a bit long winded to make much difference. I'd expect to see much bigger fins on the back of drivers first, but the point about sealed units is well made. Perhaps large fins which go right through the back of the cabinet, coupled with an external fan would be one way to go if there's a genuine problem. Of course those with 8*10s merely need to refit the heat exchanger to their fridges to solve the problem...
     
    Last edited: Oct 27, 2018
  5. Kro

    Kro Supporting Member

    May 7, 2003
    New Jersey
    I feel like this is probably most likely. I'd also presume that if your cab was just "warm" to the touch, it was still probably pretty safe. Sure the voice coil is probably much hotter inside... what cab did you say you were using again with your D800+?
     
  6. voided3

    voided3

    Nov 11, 2008
    It’s an Ampeg 410HE loaded with Eminence Basslite SC10-16 drivers, 4 ohm total impedance. I run the amp in 2 ohm mode to drop it down to 600 watts.
     
  7. seamonkey

    seamonkey

    Aug 6, 2004
    JBL has. They designed cooling fins in the ports back when they used internal class-ab amps.

    Drivers are designed to radiate a lot of heat right through the cone. So special venting may not even be needed.

    But if you want, Good cooling can be had by using the chimney effect. Have a port near the bottom of the cab and another near the top.
    Hot air rises and vents out the top, while cooler air pulls into the lower port.
     
  8. Kro

    Kro Supporting Member

    May 7, 2003
    New Jersey
    Kind of hard to do with a sealed cab though. ;)
     
    Coolhandjjl likes this.
  9. saabfender

    saabfender Banned

    Jan 10, 2018
    Indianapolis
    I fully applaud the amount of thought that went into solving a problem that doesn't exist.
     
  10. 4 Strings Good

    4 Strings Good

    Mar 6, 2014
    Aww, man! I thought this was going to be another @Rumbledore post!
     
  11. 40Hz

    40Hz Supporting Member

    I would think if heatsinking would materially benefit the speaker coils, it would already be there. Manufacturers don’t tend to skimp on reliability enhancements. Especially when it comes to something as inexpensive as a passive heatsink. But wouldn’t the speaker’s metal frame already serve as a heatsink of sorts?

    I think it is being done on some horn drivers looking at the finned backs on many of them however. So maybe those actually do need it since they’re often mounted to synthetic rather than metal horns?

    Don’t know.
     
    Last edited: Oct 27, 2018
    voided3 likes this.
  12. ThisBass

    ThisBass

    Aug 29, 2012
    Germany
    for cooling purpose it may make sense if temperature gradient was high enough. I don't think speakers can heat up the baffle to adequate highish temperature to make this "benift" workable
     
    voided3 likes this.
  13. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    In reality, the thermal load on the voice coil isn't all that challenging for the most part. The exception is drivers that have very large overhang since much of the cooling is due to conduction of the wire in the gap to the magnetic structure. At 150 watts per driver, that's not going to be an issue and at much more than that power the mechanical limitations of the driver are going to dominate.
     
    lowendrv and voided3 like this.
  14. Kmonk

    Kmonk

    Oct 18, 2012
    South Shore, Massachusetts
    Endorsing Artist: Fender, Spector, Ampeg, Curt Mangan, Nordstrand Pickups, Korg , Conquest Sound
    Aluminum is actually the most common metal used for heat sinks.
     
  15. DAB

    DAB

    Mar 28, 2016
    If the amp produces say 500w RMS, the cab will heat up noticeably. I would expect the cones to become a lot warmer than a plywood baffle thou, due to the lower thermal resistance. If you look at the cab as a cooling system, it should dissipate the maximum watts for a given temp difference between voicecoils and air in the room. What high power drivers have in common seems to be large diameter voicecoils and a thick frontplate in the magnetic motor. Where it matters most is where the heat transfering areas are the smallest and that would be closest to the voicecoils. A alu baffle would help but would probably be less cost effectice than measures in that area. Eminence kilomax has a cooler attached directly to the polepiece in front of the membrane.
    Eminence Kilomax PRO-18A
     
    voided3 likes this.
  16. DAB

    DAB

    Mar 28, 2016
    A way would be to use aluplates on each side of the top plate to dissipate heat but without being part of the magnetic circuit. I dont know if that method is beeing utilised in any comercial design thou.
     
  17. Gilmourisgod

    Gilmourisgod

    Jun 23, 2014
    Cape Cod MA
    My ancient Peavey Mark III head has a large finned aluminum heat sink that doubles as a cord wrap, I remember that would get quite warm, but never really hot to the touch. I can’t imagine a speaker cab generating more heat than an amp. I figure if Mesa didn’t see the need, there probably isn’t one.
     
  18. brianrost

    brianrost Gold Supporting Member

    Apr 26, 2000
    Boston, Taxachusetts
    Overheated speaker cabinets? Were you playing in a steel mill? :roflmao:

    That's something I have never experienced. Are you sure it wasn't warm because of the amp that was sitting on top of it?
     
  19. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Any driver with a cast aluminum basket has the basket attached directly to the top plate (not the pole piece like the KiloMax) there is some conduction that occurs here. Some manufacturers also tightly fit (or use an adhesive thermal interface) an "heatsink cap) to the back of the driver (more common with Neo drivers due to how they are constructed) which also conducts some heat from the structure (but plays an equally important cosmetic role)

    Guaranteed that if it was necessary it would be present. All heatsinking on the Subway amp is internal, fan cooled, effective and fully modeled to insure plenty of margin for 2 ohm stability.
     

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