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SBL cross-over

At a tangent but I guess might be of interest.

I have recently installed a brand new pair of passive SBL X-overs made at Naim a few weeks ago. They are now settling in and are significantly better that the original 19 year old ones.

I have no idea what components are used in either the original ones or the latest ones but they certainly sound different and better to these ears. Very much like a veil over the music has been lifted.
 
Naim may now be using more polyprop caps than before but I doubt there are that many changes as they wouldn't fit in the vac formed ABS case they use.
 
I thought that, there're a couple of pics on the web and they are at 90º to each other. As you saw, the provenance is closed stock I imagine they are as intended.

They are loose, I plan to secure them, if I can twist I will?
 
rontoolsie said:
I also found out that a very well designed crossover with premium parts was quite superior to Snaxo/Supercap etc with multiple amps.
Click to expand...
The SNAXO uses 'standard' Bessel transfer function in the electrical domain, which is no better or worse than a generic linkwitz-riley or other crossover topology. If the objective is seamless crossover and even summation in the acoustic domain, then the native response of the drivers matter greatly. There are very few drivers that are completely flat within their passbands, let alone in their (crossover) stopbands. A tailored crossover (active or passive) network that incorporates the drivers' native behaviour has the potential to sound much better than any generic crossover network.

The only real advantage of active filtering and direct amplifier connection to drivers is in the LF area. But what one gains in better control in the bass, one also loses in gravitas and/or depth. Deleting the inductor(s) increases electrical damping, and lowers the overall system Q. This tends to make the bass sound leaner (in sealed systems) or may throw ported systems out of alignment. I feel decidedly nervous about direct amplification for expensive tweeters and uber-rare midrange drivers.

I await hacker to try the active filters I designed for his E-IIIR loudspeakers. I'm prepared to bet that he'll be a little disappointed by the marginal gains he'll realise (if any) over the passive filters he's already enjoying.

James
 
I think its important to put some costs into this, the first DIY project cost well over £100 , the Audio 42 I priced conservatively at £400+ .Compare that with a Naim retail of £220 (£40 parts??) you can see there's scope for improvements.

These are not accurate, no level matching and on different days, but I think interesting

SNAXO + SBL
SNAXO + sbl by levs the diver, on Flickr

Audio 42 + SBL
IMG_1444 by levs the diver, on Flickr

The SNAXO puts quite a bit more energy into the lowest registers.

I may get chance to do the originals later in the week, better if I started fresh and monitored levels :D
 
@ divedeepdog, both those frequency response plots are pretty poor and wildly different from each other. If that is truly representative of what a Snaxo does then it is hardly surprising that people say active SBL's have 'way better bass' - they certainly have a heck of a lot more of it! A difference in frequency response of that magnitude is going to sound very different and swamp any active V passive issues/benefits.

On the other hand, the sweep Ron has supplied is surprisingly flat for an 'in room' measurement - particularly a boundary loaded design.
 
divedeepdog said:
I think its important to put some costs into this, the first DIY project cost well over £100 , the Audio 42 I priced conservatively at £400+ .Compare that with a Naim retail of £220 (£40 parts??) you can see there's scope for improvements.

These are not accurate, no level matching and on different days, but I think interesting

SNAXO + SBL
SNAXO + sbl by levs the diver, on Flickr

Audio 42 + SBL
IMG_1444 by levs the diver, on Flickr

The SNAXO puts quite a bit more energy into the lowest registers.

I may get chance to do the originals later in the week, better if I started fresh and monitored levels :D
Click to expand...
All bets are off if the measurements were carried out at two different locations. I suspect this is the case because there is a peak around 167Hz in one whereas there is a dip in another. This is likely a room, rather than crossover effect.
 
YNWOAN, I certainly heard more bass output with the SNAXO. The sbl is still a very 'tight' speaker, but Naim are in business to sell box's

I've got the Xtz for a while longer I'll try and do a more methodical and measured test, but borrowed Windoze lappy, and swapping cables aren't first place for fun ;-)

I got the SNAXO in spite of being happy with the first DIY Pxo, every thread you mention sbl is followed by 'you must try them active'. I like to talk from experience, the benefit of Naim box's us we can try them (2nd hand) for free.

I'm sure most people are happy active, the piminary tests sugest much more bass at least !


*its an in room response, mic in front of one speaker may give a more accurate reading ?
 
Hoorah, another set of SBL paxos built!

I went for a smaller footprint box, to enable that I split the board layout into two, HF on one, LF on the other. Then I stacked them "over-under" style and popped them in a compact box.
(cables are make do for testing)



 
Well, taken the plunge and cooked up a pair of home brew XO's for my SBL's and they are now singing away.
Based it on isnchys's post but used pieces of phenolic sheet as I want to keep the Naim crossovers intact for comparison.
I like them ! more of everything, detail, space, 3d, bass drums have that 'blat' as the pedal hits the skin just before the drum shell starts to resonate (Yes, I play drums )

Have fitted bipolar electrolytics in the LF but have some polypropylenes from Wilsmlow on order, so I'll see how they compare.

One other thing, 'divedeepdog' previously mentioned about locating the PXO's near the amp and running dual cables over to the speakers. The Van Damme studio 4 x 2.5 mm might be an option here. Anybody done an A-B comparison on this one. I currently have single run NAC 5 and don't have anything else to compare it. I'm thinking of NAC5's inductance.
The amp is an NC200'd CB 250, which should be happy with any cable. Suppose I could try some twin and earth.............?
 
The PXO's are too big to hang off the back, putting them near the amp is about logistics as much as sonics.
The Audio 42's are in a full width case, so near speakers isn't an option.

Against all NAim folklore, I (along with Andy and his Nait2) really like Audioquest Type4 speaker cable, twin earth mains cable might be a good choice :D

Great to hear of another build, can we have some pictures ?
 
My SBL's have come over all sweet n fruity

IMG_1644 by levs the diver, on Flickr
not quite what I wanted (9700) but these D2905/3000 were the right ££ to try. Sound promising on first listening.

If successful, I'll make some new face plates and fit them in the original box's
 
Can you do some measurements?

I could do you laser cut acrylic adaptor faceplate if you wanted. As I actually have met you - mates rates.
 
Thanks Mark, I've got a lathe :D Would you recommend Acrylic or aluminium?


Measurements might be more difficult, regular trips to London (and friend with XTZ analyser) have dried up. I'll look into (free) software if anyone's got suggestions for Mac?

Lots of swapping to do before I get the tools out, although first impressions are good.
 
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