Seen your device and was wondering if a similar type device could be used with a heat dissipator coming forward thru the dust cover instead of out the back. How much heat accumulates in the rear space with the vents inside the rear space instead of going out? Have very little rear space room in present design. How about a similar design as yours with a heat dissipating plate attached to the rear wall but instead of venting into the rear space going outward past the dissipating rear plate...looks do able. Presuming the distance between speaker and rear space wall is little 1-2 inches do you think it is worth it to keep rear space as cool as possible. These will be professional use flown speakers.

When I designed the cooling plug, my first instinct was to duct heat out of the cooling vents, rather than allowing heat to build up in the rear chamber. I expected air temperature would normally rise in a speaker with a small rear chamber used at high power levels, which would make the cooling vents less effective. My plan was to use a heat exchanger to cool the air ducted into the vents. What I found was that air temperature wasn't a big problem. The biggest problem is the heat that is retained in the magnet structure. It's like a thermos bottle, a large chunk of steel surrounded by ceramic. That's where the heat buildup is.

• Loudspeaker motor cooling methods

We miss you at audio asylum!! Too bad for the cat and mouse games played over there at times. Remarkable results with these VC heat dissipating plates. Looks like I will not have another pro use (or even home) speaker without them. Apparently not worth having vents going outside of rear space (with the possible driver parameter changes) since most VC damage is a local heat phenomenom. Large Aluminum plate will also help dissipate rear space heat anyway.

From my days as DIY plummer I remember not to contact Cupper tubing with other metals since it leads to a chemical reaction. Therefore the use of cupper clamps to hold cupper tubing in place. Will look into this further to be sure since seems cupper tubing is ideal for wicking away VC heat out to a lightweight aluminum plate for dissipation. But likely the cupper would chemically react with the iron in the pole piece even with thermal paste in between.

Can see a big advantage in using these heat dissipating techniques not only on pro use speakers but also in high resolution dynamic low power drivers with edgewound aluminum cupper clad VC wound on cardboard etc formers. Like old Altec and JBLs.

Anyway thanks Wayne for all the free education and info and congrats on your fine speakers.

Nicolas

I was readind this post and Wayne have in fact excelent information. Congratulations, one more time.

The name for this kind of corrosion is Galvanic Corrosin. Also very important is corrosion under stress. Look under "Galvanic Corrosion Tables". There are very nice ones. I had a problem with corrosion of magnesium speakers (maybe is better to get nuts and bolts of similar material or then use nylon spacers).

*nice read: Fastener Design Manual - http://www.tcnj.edu/~rgraham/barrett/manual1-A.html

PICTURE FROM: http://ops.dot.gov/regs/small_ng/images/chapter3_table.png

• Galvanic Corrosion [2. GALVANIC (Two metal).]

Again Thanks.