ATC SCM40 vs SBLs. Round 2

Ive been running some lovely SCM40s recently as a flight of fancy. Paired with an LP12/Nac52/supercap/250 they sounded marginally better than my Sibbles. Bass was more extended and the treble marginally smoother. Ran this for about 3 months. Heres thd fun bit. Swapped the 250 for a pair of 135 a couple of weeks ago and that saw a general improvement all-round. The jump in SQ is well documented with that particular upgrade and I recognised most of what has already been written on the subject. Last night, I thought I’d swap the sibbles back just for comparison. Oh my…

I always thought a 250 was pretty good with SBLs. Turns out 135s are much, MUCH better! The clarity and openess are just so much nicer than the ATCs. Female vocals especially are a delight. I realise now that whilst the former had better range, when swapped for the SBLs it was like a blanket had been removed from my system. I remember reading somewhere on these pages that to better a pair of SBLs nowadys, you’d be looking at circa 7k.
Going to do a lot more comparisons before I make my mind up completely, but the SBLs really are such a quality speaker.



Hi Clive, Interesting… It looks like we have not that dissimilar systems, so be I’d very interested in where you finally land once you’ve had chance to do more comparisons…

Hi Bokermonz

What do we share?..

I have a Vertere MG-1 turntable, plus 52/SC/300dr/SBLs. So I’m think a turntable, 52/SC and 300dr (which is at a similar level to 135s) and SBLs of course…


Hence why I own a pair of SBLs MK2 and SL2s :grin:

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How do you find the SL2s in comparison with the sibbles HiFiman?


The SL2s are a smidgen better but there’s not much in it, both are excellent. If you love what the SBLs bring then SL2s are for you, easier to setup, more transparent and I would say the bass is slightly deeper.

…but I could easily live with the MK2 SBLs.


I think SL2 are more sophisticated and have better resolution and control at both ends of the frequency range.

I have only run mine active, and swapping SBL to SL2 in this configuration made everything better in my view. Still ‘related’ but a class above. Cannot think of a negative.


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Price perhaps? I’ve payed 550 euro for a mint pair including 2x5 metres linn k20 with Naim plugs.

Oh, the sbls are not so mint anymore in our kid rich fam.

For my ears, a 250 is not really enough to hear what SCM40s are capable of. Even a 250DR was a bit lacking when I tried the combination. I’d put a 300DR as minimum (not heard NC 250 with them), but best of all are the actives. I don’t find it surprising that ATC sell most of their larger speakers in active form and in that context SCM40As are something of a bargain. IMO, of course.


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Interesting. I remember when I compared the 250 with the 135s (albeit with different speakers, namely the Royd A7), I found the 135s better than the 250 but not (to my ears) by a margin than justified the extra cost. That’s why, when I was ready to upgrade the power amplification in my system, I chose to activate my SBLs with a second 250 instead of running them passive with a pair of 135s.

SCM40A vs active SBL would be an interesting comparison. Would also really like to hear active ATCs on the end of Naim power amps. Anyone got a hacksaw? :grinning:

Very interesting to read your comparisons as I changed from SBL MKII to SCM40 passives and thought it was the biggest single upgrade of my entire audio journey. However, I remain convinced that SBL’s are hugely room dependent. They are undoubtedly a real bargain secondhand and you’d struggle to better them for sub £1000. They’re just incredibly detailed and fast but where I found them lacking was in warmth, slam and genuine bass power.

I found myself tending to play music that suited the SBL’s (basically well recorded light rock - James Taylor, Joan Armatrading, Dire Straits, Eagles etc) and steering clear of poorly recorded heavier stuff (U2, REO Speedwagon, Rolling Stones). With the ATC’s due to their greater warmth and bass extension I now play everything and am continually shocked by how great they sound. When I played Diamonds on the Soles of her shoes (Paul Simon) on both speakers I found the drums just immense on the ATC’s with a sense of the air in the room being jolted whereas this just didn’t happen on the SBL’s. Miss You by the Rolling Stones just came alive on ATC.

The SBL’s are now performing very well as rear speakers in the surround set-up with SCM40’s at the front so there’s life in the old buggers yet!!!

I should say I was driving them with 82/Hi/250 (all olive). Olive 250 is the absolute minimum to drive SCM40’s though I think and even then be prepared for the odd thermal shutdown at party levels… Not a problem at ‘session’ levels though. The new 250 is a very tempting proposition because it reputedly betters the drive capability of 300DR.

But you know what, if you’re loving the SBL’s that’s all that matters - we all have different ears and rooms! The only thing that matters is finding what you love.



I found ATC really came into their own with the active versions.

Glad to hear SBL’s still sounding good, classic pair of speakers!



Interesting. I find warm recordings sound warm on SBLs. I also think that they show whatever bass is on the recording. They are like monitors which of course is not everyone’s cuppa. But then I preferred SBLs to SL2s on dem so what do I know? :rofl:


This is my experience too. In their current setting, now of 20 years, I’ve never felt they lack warmth, or a deep tuneful bass. In two previous living rooms, where I had them firing across the room, rather than down the room, as the do today, they did struggle in that regard. I’ve always liked their speed though, and haven’t yet been tempted by anything else. I’m always interesting to hear people’s experience of direct comparisons to modern speaker designs, especially as they represent the most underinvested part of my system by some measure. My current pristine pair of walnut (I think but am not entirely sure) SBLs, cost me the princely sum of £339.


Thanks for all the interesting contributions…I think I should reiterate that I really like the SCM40s. What I’m trying to convey is the synergy that SBLs have with 135s. I think its fair to say that in my set up the 135s drive the SBLs effortlessly, where as the dont really bring out the best in the SCM40s…only a more powerful amp would do that. Something around 150w maybe? Another thing is the genius design of the SBLs. For a box that size they can generate an amazing expansive sound stage and if set up correctly and with serviced xovers, can also reach down pretty low in the bass department. They are no lovers of poorly recorded material though and for that I forgive them.



Not in my experience. I’ve used my SBLs in five different rooms (in 3 countries on 2 continents) and have always had consistent results from them. I have never felt they sounded better or worse in any of the rooms that I have use them in.

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Hi Clive,

That clarity is superb. When I got a pair of SBLs I was using an EAR868 into an EAR534. Now I loved that pair of amps, and had basically used them for a decade.

I swapped in one of my old 250s, and for the first time it equaled the 534. I then tried a 250DR, followed by a 300DR. The 300DR stayed.

Adding an pair of cross-overs with modern electrolytics gave another nudge too.

What cabling are you using? A5?


Hi Paul, my experience was that they really need a solid brick or breezeblock wall behind them as they didn’t suit a timber framed house I lived in for a while and particle board internal walls didn’t work for me either. I’m glad you found success though. I’m certainly not decrying them, they were my main speakers for about 20 years and they do a lot of things really well!

I noticed interestingly that when Kate Bush sold her house she had SBL’s which is quite something!



Im using some witchhat A5 substitute…
…really need to get some actual A5 though this synergy is anything to go by!