SpeakerTalk

[Stuarth]

I recently acquired a pair of original KEF 104's for £200. My system consists of a Classe CDP-10 CD payer, Classe CP-35 pre amp and Classe CA-101 power amp. I was previously using a pair of Dynaudio Contour 1.8 MK 1's. I'm very impressed with the KEF's sound quality. They're a definite improvement over the Dynadio's - fuller, warmer and possibly slightly more detailed. My room is 24ft x 15 feet, and I'm wondering if anyone knows of any mods which might improve the bass depth. I find the best overall balance with the speakers about 3.5 feet from the back and side walls.

Can they be bi-wired? What difference does the ab crossover make?

[terry]

Thank you for yoour interesting post. The Dynaudio Contour 1.8 is certainly a good speaker system and so to read that you prefer the 104s is music to the ears of all of us at this Forum.

The story of improvement offered by the 104aB is found in the pdf linked from this text. Advice about positioning is found in the pdf linked from this text.

I personally haven't owned 104s and so cannot contribute further to the discussion about positioning. Hopefully some 104 owner will see your post and help.

Now that you have 'discovered' vintage KEf speakers perhaps you should try to listen to a few more variations mentioned in the site. Also consider the diy variations. In my opinion the 'true' 3 drive unit KEF systems can offer more than the 104s and of course especially in the bass area. The 104 has of course an ABR.

[Stuarth]

Thanks for that. I think I'll put the Dynaudios on Ebay. I downloaded the PDF about the aB crossover circuit. If I knew the component values and the recommended types of capacitor etc. I'd get the soldering iron out and attempt to build a pair...

[Almtb]

Check out - http://www.hifiloudspeakers.info/Anatomy/Crossovers/104aB/KEF104aBcrossover.gif

When I had a DIY 104ab I used a 2.7mH First inductor for the bass section. In my experience this large inductor is used to combat the rising response of the B200 with a lower value inductor giving more midrange output.

As the first inductor is pretty high value then using an inductor with larger gauge wire (and even better air cored) will help efficiency and sound quality. Unfortunately a large air cored inductor won't be cheap.

Good luck.

Al

[Stuart Booth]

This is where the 'techies' go and comit the noble Japanese act, but I live in a house, not in a perfectly symetrical anechoic chamber. I am not interested in theoretical infinitesimal improvements, but in real sound. I will however admit that the aB modification is a must.

Throw away the rubbish stands (if you've got them) put some hefty spikes in the bottom and stand them on a solid piece of hardwood or marble or even a paving slab. Sand them down and give them a couple of coats of yachting varnish - (a bit like a stradivarious, which I think has 12 or more coats.)

Then do something even more horrific - take out some of the foam - there's too much of it and it slows down the reaction of the ABR Believe me you will live with any boxiness and love the increased speed and tone of the bottom end, be it piano, double bass or bass guitar. Yes the box may resonate, but so do live instruments. Finally, if you want to be really daft, try putting a heavy slab of something on the top. I've done it and it works.
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Stu.

[Stuarth]

Thanks for the advice. They're currently on spiked metal stands on a suspended wooden floor. I'll try slabs underneath, and I'll experiment with the amount of foam damping. As for inductors, I've seen 2.5mH air cored for around £16

[Almtb]

[ColinR]

Why not go the whole hog?


Flog the 104's and get a pair of Reference 103's .

[proffski]

Too easy and bass too fast!