Active SBLs

Hi Debs, I was disappointed at first, the 300’s seemed very bright but I’d not had brand new before and the burn in took a long time.
I’d had 135’s for about 20 years and suppose I was just used to how they sounded and these were different.
The 300’s certainly give more detail and much better base with my system and now I wouldn’t go back to the 135’s although it would be nice to be able to do a comparison !


Sorry I can’t spell, it’s a hot night and the beer is going down too well !!

1 Like

Especially if the beer is the same as your username. :grinning::grinning: we did the brewery tour some years ago.


Exactly the thinking behind the original configuration of active SARA and Isobarik set up. I know back then everyone was still learning, as we are still today.

I only ever had 250’s on my Isobariks, the 135’s hadn’t come out yet. (My 250’s were pre Chrome Bumper even), so the line input to the power amp was a stereo XLR, and it wasn’t simple to re-configure the amps as you describe with your 300’s. I wish it was like that back then.

I did get busy on the soldering iron making up din patch boards so you could try things on the fly, but I’m sure this was detrimental to the sound. I had no idea of Naim’s star earth philosophy then so there’s the first flaw in my experiments right there.

I also made din-rca’s so I could plug in other amps downstream of the naxo. A perennial problem though with experimenting with active set-ups though is you need 2 or three of any particular model power amp to try. Not many dealers can afford to have three of the more expensive power amp models in stock, let alone unbox them and so potentially devalue them, just to muck around.

I was the most ardent of active promoters, had Kans, SARAs, Isobariks, Meridian M2s, Spendors, some home builds, and more active at one stage or another. To activate the Kans, Spendors and some other speakers required me removing the passive cross overs to just get it happening. (Although I was doing that anyway as the idea of having your passive cross over external to the box was “a thing” back then, and although to my knowledge no mainstream manufacturers did it, (we are talking early 80’s), crazy people like me were in the habit of trying this. Just after I left hifi retail, (1987), Linn put the cross overs externally on the Isobariks.

I spent 10 years doing custom home theatre in the late 80’s - mid 90’s, and got pretty good at doing custom active sub-woofers. This really confirmed my own bias towards fast, fast bass. We at the shop despised the wooly bass that a lot of the gear had back then. I also think bass control and speed is a big part of the PRaT factor that we get excited about on this Forum


Like your term “cabled horizontally”. Very apt

And to add, I never thought to just rewire the outputs of the NAXO.

I bought second hand Kans with the objective of making them active, but never got around to it, but they are still on my bedroom system.
I loved my active SBLs (4x135s) and took a reluctant upgrade to Ovator 600s, still with the 135s, but I don’t have the space to add more 135s or a 250 (routing the extra cables would be problematic.

I’m wondering how active compares with having a single 500. I bought a 2000 500 serviced late 2016 but not DRed. It is also partnered with the previous owners serviced but unDRed 552. Traded in my 252 and 300 DRs. Absolutely no regrets.


1 Like


back in the 90s i heard an active 4-pack SBL system [ CDS / 52 / 4 x 135s / SBL ] and not only liked the sound but forged the idea in my own mind of the sonic performance plateau i would one day aspire to be one day.

However, a couple of decades later my long term plan to acquire the 4-pack became somewhat superseded by the domino effect of obtaining a 552 about 5 years ago, which i originally ran passively with 2 x 135s into SBL, all fine and good but the question then was to either go active with a 4-pack, or buy a 500.

I have never experienced a direct A / B comparison between 4-pack vs 500, but there exists written testimony everywhere to confirm the 500 passive trumps the 4-pack hand down, and not to mention the illustrious synergy with 552, so i too went down the 500 road, who am i to disagree…

My opinion of 2x135 vs 500 into SBLs is a difference of enjoyment, yes the 500 is clearly an upgrade with more refined detail especially bass but the question in my mind has always been with the capabilities of the sibbles with a 500, and in that the 135s have for more synergy with sibbles and seem no less enjoyable in the overall musical sense.
Another way of terming this is to suggest the SBLs are bottlenecking the 500 which is probably true but so what, it’s a very good place to have a bottleneck if you gonna have one! : )

Wearing my 20 years old rose-tinted glasses i seem to recall hearing more “enjoyment” and “boogie factor” coming from my dodgy memories of 4-pack SBL. So perhaps i should have gone in that direction instead of a 500 (?) and simply to keep my SBLs as “active” end game. This would have saved me a bundle of money too.

Or then again perhaps now i have a 500 i should simply move with the times and replace the SBLs with a modern loudspeaker that is able to show more of what the 500 is capable of.
[ Please don’t suggest any! - i’m only supposing not asking! ]

There is much to like about the accordant synergy of the 552/500, so perhaps it’s best to plonk the best loudspeaker one can find [ to suit ones cost, room, sound, and aesthetics ] and then forget fussing about with hifi and get on to enjoy music for many years to come.

Anyway, this thread is about Active SBLs, which maybe classic in the historical sense but still very capable of producing a fine sound with boogie grin factor 10 thrown in.
Would be interesting to know how @mayburyds is progressing? …and hope he is at least relieved not to have any 1st world 500 series problems to cloud his active journey : )

1 Like

Hi Debs

Thanks for your interesting reply. Sorry for the diversion, but it seemed a question that should be asked. Of course the 500 could be seen as a step to active SBLs!

Like you I think this hobby has consumed too much cash but at least we have reached a happy resting place. I just wish I hadn’t meandered as much, but I did try to make other solutions work. I’ve probably got 12 years before the 552/500 needs another service and perhaps that will be the time to do the DR.


I wonder if I should have tried a single 500 instead of going active into my SL2s with a pair of 300drs. There just isn’t chance to try these things out, sadly and I did it all in stages


I’m talking from limited experience because i haven’t tried every conceivable variation either, but i have a good idea that if SL2s or SBLs are the ‘end-game’ speaker it’s a really good idea to have them active.

I won’t suggest a 500 is too powerful for SBLs [ because they ain’t ] but do think it maybe unnecessary powerful, maybe this also applies for SL2s. For some time i’ve suspected the 300 [ or 135s ] are the perfect adequate amp power for SBL or SL2. The 500 works fine too but i believe it could really do with a more sophisticated - lower bass frequency range loudspeaker to release it’s full potentially, and that probably excludes naim boundary speakers.

Having a pair of 300s driving SL2s active makes perfect sense to me : )


Well they are sounding pretty darn fantastic at the moment! :heart_eyes: it’s more of a curiosity thing (and if you take the cost of supercap and snaxo and a pair of 300s against a 500 then the gap is negative at new prices. Eek). And I have never even heard passive v active back to back - looking forward to the Kudos tour when it reaches the north west. Oh and I suppose it might have been an idea to try the sbls active too but I prefer the sl2s passive (still have the sbls)

The SL2s are the end game for the foreseeable future (never say never). I just don’t see any need for anything else. They don’t make the sofa shake (a friend has some b&w Daleks (can never remember the number) which certainly do but they just aren’t my cup of tea) but by heck the SL2s sound fantastic - everything seems to be nicely run in now.

One thing I really like about the 300 is the excellent quality at low volumes - doesn’t need cranking up. (Well low by my standards - everybody else in the house seems to think my low is too loud :roll_eyes:).

Sorry - rambling…


Debs, I too have considered changing from SBLs (I use a single 300). The problem is that few if any are boundary designs. Another issue I have is that SBLs have a unique set of strengths and weaknesses which really suit me. Having listened to a relatively small range of possible replacements nothing really impressed tbh. Yes, you get more detail, better imaging etc but not the engagement that I love. Looks like they are going to ‘see me out’…



Hi Stu,

I am with you here. I read @Simon-in-Suffolk description of what he terms the Mandelbrot effect and recognised that with my cat killed Focal 1008be I could more easily listen into and around a recording than I probably can with the SBLs, but, I know I can easily recognise a difference without always accurately determining whether it is an overall improvement. I find it is too easy to move from one compromise to another and kid yourself that you have taken a stride forward.

One area where I think the SBLs and Focals both work well is in being transparent to upstream changes.

Overall I think I know how the Focals are ‘better’ than the SBLs in certain areas, but the SBLs are a great package and I am very happy to stick. I just wish I’d tried them sooner, but then I am using EAR Yoshino amps and so I go easy on myself!


1 Like

I am only thinking about the active route and have been looking for a CB 250 to see what is around, but as I said before they are pretty thin on the ground, as are CB 135’s .

The more realistic upgrade option seems to be a 300dr but funding could be a problem with the internal finance department!


I got a non dr 300 to replace the olive 250 I had running my SBLs. Superb improvement. You could get a non dr 300 for less than the cost of a couple of 250s plus naxo etc and just do the dr later if you wish to as and when money available. Or just service without dr when needed if money tight

A certain Mr Vereker told me to keep the amplifier higher in the range for the tweeters.


Can’t believe the response to my question! The amount and quality of information has been amazing!

Many, many thanks not only for the information about going active but for all the alternative possibilities.


This topic was automatically closed 60 days after the last reply. New replies are no longer allowed.