Aluminum vs. copper voice coil wire?

[capslock]

Is there anything to be said against aluminum wire, as used e.g. in most Scan Speak drivers with a -00 suffix?

I was specifically thinking of temperature compression, i.e. the resistance increasing in the course of a burst. But resitance change between 273 and 300 K is 10.55% for copper and 11.56% for aluminum, so this is probably nothing to worry about.

Are there any other points? Like how contact to the wire is made? Also, there isn't any OFA (oxigen free aluminum) with those magically aligned crystals yet

[hifi]

one thought is that aluminum is much lighter then Copper...but than again this is not an MC pickup..

/micke

[navin]

well edge wound flat coil will have better temp dispersion as there is reall god contact between layers.

if used with al wire one can used wire teated with UV. this wire has a thin film of insulation on it and this insulation while being electrically good is also an excellent conductor of heat.

we build lifting magnets this way (see http://www.emagindia.com/magsep.htm for pics).

al is lighter and pound for pound can carry more load. al is brittle though. copper is more ductile. the pro and cosn work out that i's use al for tweeters and cu of woofers and mids where weight is not such a problem the cone weighs much more.

[FrankDIY]

aluminum does not rust (oxydation), copper yes.

[SY]

Rusting is probably not an issue with varnished wire. Al vs Cu is a matter of an engineering tradeoff between resistivity (Al is higher), weight (Al is lower), and heat capacity (Al is higher).

[navin]

rust = oxidization. the difference is that for iron the rust contineus after the outer layers has oxidised. for al the ALl2O3 layer protects the lower layers.

by controlling the al2o3 layer one can create preanodised aluminum. this aluminum is used for window frames. another applicaiton is to use a very thin (almost transparent) layer of anodization and this is used for lighting. for more info see http://www.emagindia.com/paranew.htm and http://www.emagindia.com/alm.htm.

moderators, i am not plugging my company just using its website as a resource.

cooper also has a simialr reaction the difference is that copper goes green if it is good and black-brown if it impure. In India it is tradition to use Silver and Copper vessels to store drinking water. Yes we all drink out of silver cups that were gifted to use by aunts or uncles when we were kids. I've had my silver glass since 1972 (when I was 9).

[lieven]

something useful!!!!

a defect often encountered with square aluminium coil wire:

if a driver suddenly fails, inspect the solderings between coil wire (Al) and the souple litz wire (Cu) towards the speaker connections.
Nothing wrong with the speaker, mostly a bad soldering.

Inspect it at the back of your speaker, soldering is mostly covered with some (black) glue.

[navin]

cu-al joints are notoriouosly difficult to solder.