AR 2ax tweeter


2010-08-18 6:47 am
Does anybody know if the late production (1970´s) AR-2ax tweeter was ferrofluid cooled? As far as I remember when AR-7 was discontiuned and AR-7x was introduced, the tweeter was converted to use ferrofluid.

Information about possible use of ferrofluid in AR mid domes is also appriciated.

Best Regards

Generally speaking, ferrofluid, which is a simple mixture of oil and ferrite iron oxide particles along with a chemical to bind them, is best applied to tweeters. It tends to shake off and go flying in all directions with lower frequency units. :D

It has the benefit of damping the tweeter Fs resonance well and improves cooling.

Most of its frequency response effects occur at low frequencies around 1.5-3kHz where it lowers output by about 6dB. It has little effect at high frequencies.

After about twenty years the oil dries out and it turns to sticky brown gunge which just wrecks the tweeter. You could clean it off with tissue and apply some fresh oil bought on eBay or such if the tweeter can be disassembled, but USUALLY it's "game over", time to buy new tweeters. :rolleyes: