Impulse h2 woofer refoaming - a couple of tips
The woofer surrounds in my Impulse H2 speakers were on their last legs, my finger went through them with ease, not surprising after 25 years of dailt use but a worry nevertheless. A quick search on the internet showed some great post linking back to a refurb by Reference Fidelity Components and you tube provided some great videos on replacing speaker surrounds so I thought why not give it a go - it doesnt look that difficult.
Its not !! the most tricky part was getting the drive units out - more of that later.
Ordered a pair of replacment surrounds from Good HiFi VOF (goodhifi.com/(speakerreapirsshop.nl) in the Netherlands, under 20 Euro, ordered Monday arrived Thursday. Great service.
Anita's sticky glue is widely available in the UK and worked fine. Its mighty hard to squeeze it out of the tube so I unscrewed the top and used a very small cheap paint brush.
Clothes pegs, non in the house but Wilko had them at £1 for 36 (36 per driver is good) I rermoved these from the drivers after about 1 hour as some were starting to stick to the unit, guess I used too much glue
Wood chisel I had one of these and it was very useful.
weight to hold the surround to the cone, this was a nightmare !! plant pots, saucers, saucepans find something the right size and not too heavy took ages. I ended up with something out of a fruit juicer. key internal/external diameter measurement needs to be 15.5/15.7 cm.
shimming and centring - everything seemed to line up fine so I didnt mess with this
removing the drive units.
Internet wisdom appears to be to lie the speakers on their backs I removed them in situ. the bass drive unit is a very tight fit to the case. With the 4 retaining bolts removed and the drive units still in the cabinets. I removing some of the foam surround and threaded some strong wire round the metal arms that support the drive unit rim. Holding the speakers still and I gave the wire a very strong tug. They popped out with some speed - anticipating this I had puts lots of padding round everything near by and held the wire tight.
I tried to unsolder the cables insitu but no joy so in the end I cut them off and retrimmed the cable. On the bench it took ages to get the terminals clean again. I solder removing tape or a suction pump would, no doubt, have helped. The solid core twisted Vector cable had been pushed through a hole in the terminal and squeezed tight against both sides then soldered
Time wise the first unit took 90 minutes from start to foam on the cone, the second one 30 minutes. 2 hours to let the glue set and then about 30 minutes all in for both units to glue and peg the surround to the chasis. left overnight to dry.
all is back in place now, bass sounds a bit tighter and deeper.
far easier than I first imagined, looking back the most difficult bit was unsoldering the old cable from the drive units
if you have some old Impulse speakers check the woofer cones ..........
I guess the crossovers come next
