Example of a recent speaker refurbishment:
Before: main drivers were fried (voice coils were welded together)...here, I've carefully removed one driver which had been glued in with silicone...2 1/2 hours carefully persuading it out without damaging the cabinet! I've already replaced the tweeter unit and wiring:
Close up of one of the voice coils...insulation totally broken down and blackened:
Interior cross brace had insufficient wadding to prevent reflections at the critical mid range straight back through the speaker cone causing phase distortion:
This brace was wrapped in 35mm lambswool.
Detail of delicate solder joint to replacement tweeters (just fitted in this photo):
Existing external crossovers: A bit of a mess!:
Before:
These had been messed with over the years and some of the values were wrong. I tracked down the designer of the originals who was rather surprised to get a call from someone about his first ever speaker and crossover design of 30 years ago! Lengthy conversations followed during which various permutations were discussed, measurements recollected and final values settled upon in line with some later improvements to this crossover. I chose the components. The multiple caps are there because there are two advantages in wiring caps in multiples for passive crossovers: Firstly, they behave more as an "ideal" capacitor load and secondly, there's more chance of tolerances being met in place of using one large value cap (as in this case it would have to be).
Two of the inductors were the wrong value. I replaced these (bass and one of the treble circuit damping inductors) with low resistance air cored inductors. Caps and inductors were all within 3% on tolerance. Wiring and routing was neatened up in the process and I ensured that soldred joints were all to a high standard:
After:
Note that the original poor quality plastic bodied steel input terminals have all been replaced with quality WBT items.
Completed refurbishment project being tested for the first time....covers will be added to the external crossovers. They were simply ommitted until I had a chance to put them through their paces:
Sound-wise, these sound wonderful, and the owner is very happy with his newly rejuvinated loudspeakers which should go on to give at least another 30 to 40 years of service
Before: main drivers were fried (voice coils were welded together)...here, I've carefully removed one driver which had been glued in with silicone...2 1/2 hours carefully persuading it out without damaging the cabinet! I've already replaced the tweeter unit and wiring:
Close up of one of the voice coils...insulation totally broken down and blackened:
Interior cross brace had insufficient wadding to prevent reflections at the critical mid range straight back through the speaker cone causing phase distortion:
This brace was wrapped in 35mm lambswool.
Detail of delicate solder joint to replacement tweeters (just fitted in this photo):
Existing external crossovers: A bit of a mess!:
Before:
These had been messed with over the years and some of the values were wrong. I tracked down the designer of the originals who was rather surprised to get a call from someone about his first ever speaker and crossover design of 30 years ago! Lengthy conversations followed during which various permutations were discussed, measurements recollected and final values settled upon in line with some later improvements to this crossover. I chose the components. The multiple caps are there because there are two advantages in wiring caps in multiples for passive crossovers: Firstly, they behave more as an "ideal" capacitor load and secondly, there's more chance of tolerances being met in place of using one large value cap (as in this case it would have to be).
Two of the inductors were the wrong value. I replaced these (bass and one of the treble circuit damping inductors) with low resistance air cored inductors. Caps and inductors were all within 3% on tolerance. Wiring and routing was neatened up in the process and I ensured that soldred joints were all to a high standard:
After:
Note that the original poor quality plastic bodied steel input terminals have all been replaced with quality WBT items.
Completed refurbishment project being tested for the first time....covers will be added to the external crossovers. They were simply ommitted until I had a chance to put them through their paces:
Sound-wise, these sound wonderful, and the owner is very happy with his newly rejuvinated loudspeakers which should go on to give at least another 30 to 40 years of service
