Altec 604-8k driver issues

[big speaker]

Hi everyone on the Altec post, i have a pair of Altec 604-8k speakers in Altec cabinets. The issue i am having 1 driver sound the way it should, the 2nd driver has very little bass very thin and flat sounding. i checked the phasing all good, i changed over the crossovers fault still there. i checked the HF positive and negative all as it should be, the DC reading of the LF speaker number 1 is 6 ohms the 2nd is 7 ohms. i bought the speakers 2nd hand few years back of my boss who use to run them very loud. my thoughts were i may have a burnt voice coil, or the magnet has lost it gauss :crying:. has anyone else had the same issue and or is there anyone here in Australia with a 2nd driver etc. my work has the re-cone kits from the USA so the drive does not have to be working. thanks any hope you guys can help doing my head in

[grumpy]

Before going for a full re-cone

Might try:

running the woofer section with no crossover at all (no intermittent volume changes, mechanical noises, scraping, rubbing ...), bass returns to normal?

need a way to generate a sine wave of changeable frequency and be able to measure and AC voltage for the following:

if that fails to improve anything (i.e., it's not the crossover), perhaps test the woofer section for T/S parameters
which would give an indication of magnet strength (or loss thereof) as the DC resistance measurement doesn't seem way off (vs 6.4 ohms)

might also check free air resonance (~30Hz)... if the problem unit has gone out, there could be mechanical issues (stiffened spider, gunk in voice coil gap, ...)

http://alteclansingunofficial.nlenet.net/Thiele-Small.html

[Stew Macca]

Hi everyone on the Altec post, i have a pair of Altec 604-8k speakers in Altec cabinets. The issue i am having 1 driver sound the way it should, the 2nd driver has very little bass very thin and flat sounding. i checked the phasing all good, i changed over the crossovers fault still there. i checked the HF positive and negative all as it should be, the DC reading of the LF speaker number 1 is 6 ohms the 2nd is 7 ohms. i bought the speakers 2nd hand few years back of my boss who use to run them very loud. my thoughts were i may have a burnt voice coil, or the magnet has lost it gauss :crying:. has anyone else had the same issue and or is there anyone here in Australia with a 2nd driver etc. my work has the re-cone kits from the USA so the drive does not have to be working. thanks any hope you guys can help doing my head in


Hi
did you find the problem? I only ask because I'm having issues with 604-8H and reside in Newcastle.
Cheers
Stew