Completed Jobs

B&O RL140

Pair of B&O RL140 speakers

Bass drivers refoamed, crossover upgraded with Solen caps and Mundorf resistors, tweeters upgraded to Morel CAT298, new banana terminals.

Total cost $547

Infinity SM155

The Infinity SM155 are a 3 way with a 15" bass driver, 2x 5" mids and the polycel 1" dome tweeter

What we will be trying to achieve is to remove the bomminess out of the bass, make the mids clearer and clean up the treble.

Under first test run these speakers lack the deep bass which a 15" bass should produce, the bass has a nasty hump between 400 and 500hz, the mids kick in around 400hz but resonate at 70hz, both woofer and mids can be heard up to 10000hz.

What we will do is make a new crossover network and replace the mids.

The new crossover will roll off the woofer at 300hz, the mids will be at 200-300hz up to 6000hz, we will be using Peerless 5" mids as they can handle the lower frequencies a bit better.

To improve the bass we will also be lining the inside of the box, something that infinity dont do in these series for whatever reason, this will smooth off the bass a bit more.
The Peerless mid is a massive improvement over the existing mid used, it has a longer throw cone and coil, larger magnet, rubber roll surround and a cast alloy basket

The existing mid has a short throw, paper surround, smaller magnet, smaller voice coil, with these parameters this mid struggles with frequencies under 200hz

The new crossover utilizes 1.85mm inductor wire and Solen capacitors

The size difference is considerable, going from 500 grams to 2.5kg in weight
Once the new crossover and new terminals are fitted the box is lined with carpet underlay.  To cut down on costs the carpet underlay is a good material to use.  I would normally use acoustical foam.
A new enclosure is made for the mids and also lined.  The new enclosures are only 2 litres bigger than the original.
End result is, smoother more thundering bass from the 15" woofer, the mids are smooth and clear, the tweeter is clean and bright

crossover points are 300 and 6000hz

We stopped the hashness out of the tweeter, we removed the harshness and ear bleeding from the mids and we removed the wall hammering bass from the woofer, now the woofer is not over powering the mids

End cost is $1000
Tannoy Berkeley
Tannoy Berkeley
These came in with deteriorated surrounds, typical for its age, these are in beautiful condition, well looked after. We will also be adding some decent rear connectors.
The driver is removed and pulled apart, at the same time the crossover unit is also removed and checked over.
The magnet cover is removed, horn diaphragm removed, the magnet removed and cone are removed.
All gets checked over, voice coil gaps checked and cleaned, voice coils inspected for fatigue
All left over surround material and glues are cleaned off using a sander and whats left over gets cleaned with solvent.
This is where it gets a little messy, removing of the old foam material off the cone is hardly an easy job, this foam material is very sticky, the best is done to remove all of the old foam and under the cone ribs.  A lot of repairers dont go to this extent, they usually glue the surround on the outside, i prefer to fit it back in its original place, its more work but its a better job.
The new foam surround tucks in nicely under the ribs
The cone is now fitted back in the basket, the spider is screwed on so the nuts are left hand tight and the outter edge of the surround is glued, theres enough tolerance in the voice coil gap so the dust cap does not need to be removed and the coil shimmed.
A pair of nice Bennic speaker connectors were fitted
The edge trim is glued and screwed back on and the driver fitted back in its box, lastly the speaker gets a frequency sweep and checked for vibrations and distortions.

The job is now complete.
Kef 104.2 Speakers
These came to me with deteriorated dounuts and the owner also complained about a lack of sparkle to the overall speakers.
Looking closer at the crossover network i found some caps with much higher readings then specified and some also leaking.
What i ended up doing is replacing all capacitors and resistors, all the caps up to 50 uF were replaced with Solen Caps and from 100 uF to 600 uF i used Bennic Caps, reason being the costs of the Solen in the higher values and more so with the physical size of them, they are so large and so many that the internal volume of the box would change. Mundorf resistors were used.
Once all caps were fitted the crossover fitted quite nicely back in its place.
New dounuts were fitted to the bass drivers.
The most annoying part of this job is the removal of the access cover on the bottom of the boxes, Kef thought they were funny by not only screwing the cover on but also by glueing it thus making it quite difficult to remove, damage is inevitable so new covers had to be made.
Once the glues are dry a foam tape was placed around the edge of the inner base and the rest of the box lining was fitted.
The new cover was fitted and theres nothing like a coat of black paint to finish it off.  Now the speakers can be serviced at any time.
As a trial we used a Vifa DX25TG09 Concentric Dome tweeter in one box and the original kef T33 in the other.  After having the owner come in and do a test run he decided to go for the Vifa, the Vifa is a brighter sounding tweeter and brought the top end alive, its also a straight foward installation with only a very minor mod to the tweeter terminals.

Conclusion, the total cost came to $985, we turned a dull sounding speaker to something that can well compete with anything in the 5k mark, the bass is tight and fast, midrange is clear, bright and excellent vocals, the Vifa brought out excellent sound specially using strung instruments.  Weaknesses are the lack of low frequency notes, this is due to box design.  Music, it likes anything vocal such as opera, acoustic strung instruments such as Armik, Rock particularly Dire Straits for the tight bass.

The project is now complete and i hope the owner enjoys the results.

If anyone has questions about this job please contact me or Paul (owner)on this email 
paul@wolfsafety.com.au for info on the final result.

Hope everyone enjoyed looking at this, the next project is a pair of Tannoy Berkeley.  Keep an eye out for that.