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SBL's, go active or upgrade crossovers?

Doddy said:
Taking this thread a bit further I wonder what speakers/ancillaries would be recommended as good inexpensive examples of active operation,if such exists?
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I started off with NAC92, 2xNAP90, IXO and Credos which was the 'cheapest' option in the Naim stable at the time. This worked very well for over 10 years until some SBLs appeared and I still ran with the pre/amp/cross as above very successfully for some time; the upgrades I mention above are better still but a good 'active experience' can be had with the kit mentioned above.

If you have the chance, get an IXO as you don't need a separate PS and have a play. It seems to work with IBL>SBL and the levels controls are external, so easy to play with.

CHE
 
CHE said:
That wasn't my understanding - can you reference where this is discussed please ?

CHE
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I can’t recall exactly where it has been discussed in the past. However, this was certainly the case when I sold Naim. Drive unit levels can be adjusted but not crossover points and, obviously, a three way crossover is different to a two way.
 
Arkless Electronics said:
An active crossover must be designed for a specific speaker and the same care and attention applied to it as would to a passive crossover. Any type of universal crossover will not give optimum results. Just because an active one can give better results than a passive does not mean one can be at all lax with the design and implementation.
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My apologies to the OP for butting in here, but I can't resist asking Arkless a question about an active crossover I'm considering... That's assuming Arkless has an opinion...anyway its this: Do you have any comments on using the Deqx-hdp-express-II as a crossover mainly but also room correction on Isobariks in original condition and with modifications such as new tweeters and mids (Morels)....any thoughts will be much appreciated...thanks.

http://www.deqx.com/products/hdp-express-ii/
 
timola said:
My apologies to the OP for butting in here, but I can't resist asking Arkless a question about an active crossover I'm considering... That's assuming Arkless has an opinion...anyway its this: Do you have any comments on using the Deqx-hdp-express-II as a crossover mainly but also room correction on Isobariks in original condition and with modifications such as new tweeters and mids (Morels)....any thoughts will be much appreciated...thanks.

http://www.deqx.com/products/hdp-express-ii/
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I don't "do" digital in any way shape or form.... and prefer Wharfdale Diamonds to Isobariks!
 
The Snaxo is 'generic' because it is just a 3rd order x/o at fixed x/o point-the only adjustable feature is the relative output of the HF/LF. But having a knee in the transfer function, notch filters, phase shifts etc are not possible. So in that way a passive x/o is more specific and less generic. You would not want to used the Tukans passive x/o in the SBLs, or SL-2, yet they use the identical Snaxo.
I have found a bespoke passive x/o can indeed handily outperform Snaxo/SC etc-but does not come on the cheap. Have you seen the cost of a Duelund CAST capacitor for instance?
 
I would agree in part with Rontoolsie on this in that the Snaxo is a fairly 'generic' x/o however, when the SBL was designed by Naim it was developed to fit their active crossover and as such should marry up quite well (but a Tukan? probably a lot less so). The passive crossover then just reproduced the active slopes in passive form using very ordinary components including electrolytic capacitors & cored inductors. As has been said previously, Naim certainly wouldn't want their passive x/o to outperform their active setup. Neither the active nor the supplied passive x/o had any of the notch filters etc rontoolsie talks about above and the passives are no more or less specific to the SBL than the Snaxo - the SL2 passive has identical component values. The one illustrated above also doesn't seem to change the basic Naim x/o design - it appears to reproduce the Naim one but with much better passive components - the capacitors obviously but in particular the foil inductors on the bass look nice though their values may have been tweaked by Les to good effect.

I also tried part of this route with the passive SBL x/o replacing the capacitors with decent film ones and adjusting the L-pad on the tweeter to compensate for their lower ESR. It certainly made a nice improvement but I still think the active setup was a clear winner - maybe if I'd persevered with better inductors on the bass it may have been a closer run thing. Also replacing the caps may have altered some other interactions within the x/o such as Q of the filters so maybe it wasn't a fair comparison.

Rontoolsie's thread on the custom DBL crossover (http://pinkfishmedia.net/forum/threads/aftermarket-crossover-for-naim-speakers-dbls.7326/) is very interesting in this regard and I'm sure a further improved passive could be built for the SBL with modified transfer functions etc. if needed but as he says, this designing of this would not come cheap.

When I first went active, the cost wasn't prohibitive just adding a secondhand Snaxo and a 140 - I already had a spare HiCap - and I think was very good value for money. When I later changed the power amps, the additional costs of being active certainly racked up though I am still happy with it.
 
OK, so the way I read it you can improve on both passive and active crossovers for SBLs and other speakers via the use of better design and components, so not a clear conclusion that a passive design is better than an active design as has been suggested.

I do know that Teddy Pardo built an SBL active x-over for himself but never did market it due to the need to match something exactly with the speaker. Shame as I'd probably have bought one.

CHE
 
I've been a fan of active x-overs from the day I heard the Meridian M1s. I went from passive to active with my Isobariks, using both the Linn Aktiv, and then the Naim NAXO. Both Linn and Naim took a very 'mathematical' view of crossover design, aiming to provide just the transition between the drivers, and very little attempt was made to shape the response of the drivers themselves, which resulted in the dynamics that we loved from these designs, so if you like what the SBL does with its passive x-over then going active with a Naim SNAXO and an extra power amp will be a huge step forward. The SBL has some response anomalies, like any speaker, and a really well designed and executed x-over would address these, and probably make 'better' speaker but it may not be the speaker that you originally fell in love with!
 
Hmmm... If those ferrite cored inductors really are as bad as the measurements suggest maybe there is room for substantial improvement of the passive crossover even within the context of the standard design by replacing those with air cored like Les has done.
 
There’s plenty on active operation on the Naim forum if you care to search there - including an unofficial list of all the speakers, including non-Naim models - that the factory has previously produced *NAXOs of various flavours for. These are very much the exception however, most of the 2-way *NAXOs encountered will cross over at 2.7kHz, with a fair bit of adjustment available on the relative levels using the internal pots. These will suit your SBLs very nicely, thank you - but require a decent power supply and matched amps (with associated cables) to give of their best. I rate active operation, but in fairness have never listened to upgraded SBL passive crossovers.
 
Gosh - seems to me Les / Avondale is “the only” crossover specialist we’ve heard of or give credit to? I replaced my passive XO’s with heavily upgraded components from Jantzen constructed by master Tony of HumbleHomeMadeHifi in NL. Personally I stopped short at £650 but could have gone further. Improvement in treble and bass are beyond any £650 I could have spent on Amp upgrades. I love my SBL’s more today that when I bought them. They’re ugly - wish they were rosewood and not black ash, but I won’t be changing anytime soon. Driven off a capped 140 and sourced by a Qute. Shoebox Compactness :) I’ve never listened to active so there’s possibly bit of “ignorance is bliss” going on for me, but I just wanted to point out that the original passive components leave a LOT of room for upgrade and a consultation with HHH has delivered for me a massive performance upgrade. Next up… some of those GR-Reseach speaker cables to replace my NAC-5’s… sharp intake of breath the suggestion of non-Naim speaker cable :)
 
I think its a bit unfair to say that Jez is the only crossover specialist that we give credit to in this instance, he merely stated that generic crossovers either passive or active cannot be truly optimised for different loudspeaker characteristics other than crossover frequency or level which is exactly what the Naxo does.A well designed crossover of any type will account for the individual drivers characteristics to provide a balanced loudspeaker over the entire frequency response, since no driver is perfect this should normally involve some shaping of the output over which the driver is operating.

Rgds
Stuart
 
I went for the cheap option Wimslow refurbed my passive crossovers for £130 same deign but new caps and resistors I asked about the inductors they tested them and said no need to change.

I cant judge as not tried them and never really heard the SBLs as they had a duff driver and I decided to give them a refurb
 
We have active SL2 and are delighted and it's a big step compared to passive. We should have done it years ago.
 
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