Upgrading the Response 1SCs

Having listened to quite a few loudspeakers over the last year or so, it became clear to me that my trusty ProAc Response 1SC speakers are pretty damn good and suit my tastes very well. IMO, to significantly improve on them would cost a lot of money, so I have decided that I would like to live with them as long as possible.

WM has been telling me the improvements that can be gained by upgrading crossover components and internal wiring are very significant. So, with this in mind, and the fact that the speakers are quite old and well outside any warranty, I decided to take the plunge and upgrade the capacitors, reistors and internal wiring. The goal of the upgrade was to increase the detail retrieval and bass depth and control, whilst keeping the overall balance and character of the speaker the same - I did not want to lose the magic Proac midrange and driver integration.

The crossover of the 1SCs is quite complex, with 3 inductors, 2 ceramic resistors and 4 capacitors (3 polypropylene and high value electrolytic per speaker), and internal 79 strand type wiring (yuk!)




I decided to replace the Solen polyproylene caps with MCap supremes/ Mcap Zn high quality capacitors (the electrolytic was too high a value for a polypropylene cap to be used so I left it in place) and the ceramic resistors with high quality Caddock metal film resistors. The wiring would be replaced with silver plated copper wire with teflon insulation.

I did the upgrade in stages and listened after each stage so that I could tell how the components were changing the sound. First of all the speakers were re-wired, then the caps were replaced and finally the resistors.

Pic of the crossover with all components replaced and new internal wire. The capacitors are much bigger than the originals and the resistors are mounted on heatsinks to provide sufficient power handling.




After completing the mods, I found that there were very big gains in transparency and detail, and the bass went deeper with much better rhythmic control and less tendancy excite room nodes. The soundstage also increased massively with an image that just filled the room. I was less happy with the treble though. Somehow it had become detached and slightly obvious, and the speakers developed an ATC like tendency to analyse everything at the expense of enjoyment of the music. Luckily, as I had done the upgrades in stages I knew that this was down to the Caddock resistor in the tweeter network. Upon replacing the originals, the magical Proac midrange and driver integration was back with all of the improvements in transparency, soundstage and bass left intact.

In summary then, upgrading these components has massively enhanced the 1SCs without compromising their character. I would recommend these type of mods to anyone who wants to get the best out of their speakers, without spending a fortune. It is much more more of an improvement than a speaker cable upgrade!

However, I would recommend that only one or two components are replaced at a time so that it can be ascertained how the component changes effect the character of the speaker.

Cheers, Robbo

 

So was there a noticeable change with every new component or just some of them.

 

Chris,

each new set of components improved things. The caps brought about the biggest improvement, followed by the wiring and then the resistors.

 

Neil

Good result taking the Isc up another notch, which should make them awesome.

What size is the larger electrolytic? ICW can custom make any size polyprop. Also maybe get some big aircored inductors. This should open the sound up a bit more but may loosen the bass a bit, so may nnot be worth the expense.

 

Lee,

I am very happy with the results, a big improvement and £130 well spent. The electrolytic is 30 uF IIRC. Come over and listen sometime in the new year if you want.

If I upgrade further, I am worried about space constraints as it is only a small enclosure. maybe rigging up an external crossover is the next step.

Cheers, Neil

 

Good man.....Well done....

Try to get the Xover out of the speaker box, build it in a plastic box and also upgrade the inductors. I have used the copper foil types in various upgrades and they have always had excellent results. I must get round to doing my Apogee's sometime.....

The Audyn KP-SN type cap is a good one for Xovers. Try to change the electro too....

Regards

JC

 

Nice one Neil! You did those mods all since I was chez yours on Tuesday? I never had you down as a solder merchant

Michael.

 

Mike, I think you'll find, Robbo had already done them, last week

 

Neil

Yes, the 30uF would be about the size of a coke tin, so an external xover maybe the way to go if you want. My 47uF from ICW cost about £40/pair.

I'd love to drop by over the forthcoming weeks. Let me know if any others are around and I'll try and get over.

 

So I heard the modded speakers? Pretty impressive, especially considering their size Kept that one quiet Robbo!

Michael.

 

Mike,

Yes, you heard the modded speakers. I wasnt really keeping it quiet, I just never got around to mentioning it

 

I thoroughly enjoyed these response 1s myself when I had them, really sweet, lovely build, bass was great, I am not a small speaker fan, but these well, its got to be more complex than that. My brother has the tabletter 50 sigs, and they sound small, but the R1s...lovely...they roll off about 70 hz, but its so good, the quality, better than some floorstanders that go lower, I was not wanting for bass.

I drew the xover out.....

tweeter is : 4 ohm resistor in series, then a cap in series, inductor in parallel, another cap in series...

conventional...that makes a 3rd order on treble.

bass is: series inductor, parallel capacitor.....regular 2nd order, with a resonant filter....that is a resistor, inductor, and cap all in series with each other, across( in parallel with) the bass unit..



in yours the big inductor top right is the first component the bass goes through, the the resistor, yellow iron inductor, then the blue cap, and finally the solen cap and out again.

The 4 components top left are the tweeter bits.

 

Nice one robbo!

I know when I built my Consonance Basie pre-amp that ceramic resistors were something that you paid more to get, over and above metal resistors.

Im sure that what works in one circumstance cant necessarily be replicated in another, but am not suprised you prefered the sound of the ceramics.

Do you feel like putting the x-overs in an external box, or are you so happy with the result now that you want to leave it all alone?

All the best
Chris

 

This is an old thread, but I am amazed at the picture of your crossover. Compared to my Proac 1sc, those parts seem to be of higher quality:

 

Get the cross overs away from the speakers, build a nice damped case connect with high quality cable. I think you'll really appreciate the extra sublties that are currently being masked.

 

Hi finnegan,

I can explain what has happened. My pair of 1SCs was an early pair with the screw on back. Apparently the 1SCs are very popular in the far east and ProAc had a number of problems with the humidity corroding and discolouring the screws on the back. ProAc therefore decided to make an all in one box and without a removable back. This meant that the old crossover couldnt fit in through the front main driver hole, so I was told that they 'reworked' the crossover to fit. Looking at you picture, apparently 'reworking' means using smaller, inferior components. I'd say that was more like a downgrade!

Yours must be a later model with the non-removable back.

PS, I ran out of webspace so I dont have the picture of the modded crossover anymore!

Cheers, Robbo.

 

Indeed it is a downgrade.... air-cored to ferrite-cored inductors, lower rated resistors... was the power handling of the speakers changed at all?

 

Thanks for the explanation. I am certainly going replace those tweeter caps. There are several brands that fit.

 

V.V old thread i know but, if you see this Robbo maybe you could offer up some info and advice? I am going to attemp the same component changes and would like to know if you had real difficulty fitting the much larger Mcap Supremes on the small crossover board? Did you drill new holes to give easier spacing and where did you use the ZN?
Steven.

 

Mundorf Supreme sound very nice, but the treble has increased in every speaker that i've tried them in. Unless you're prepared to mess about with padding resistors, i'd use something like Jaztzen Z-Superior

For bigger caps, i'd use Ansar


The crossover in the picture looks very similar to my old Proac studio 100. I drilled extra holes to fit the new components in mine and used cable ties and a small dab of glue from my glue gun.