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Aftermarket crossover for Naim speakers (DBLs)

Originally posted by Mr Tibbs


Very much in agreement with James here. It does make a difference to have everything soldered up carefully and with special attention paid to wiring layout. There is a lot of current flowing in a XO, so as much star-wiring as possible reaps dividends.

Mr Tibbs
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Hi Davie/James

Ever thought of trying the old Cardas solder out for this, I used some on my recent Ittok re-wire and it seems to 'stick' well to everything, which would suggest that it migrates quite well into all the 'nooks and crannies' as it were.

Just a thought ....

Mike (not Mark, James)
 
Sorry, Mike (not Mark :D)

I tried to return your last PM but your inbox is full. Will try again tomorrow. As for solder, I have a spool of silver loaded solder but find the standard 60/40 stuff works just fine as long as there is plenty of conductor to conductor contact and I'm not relying on the solder to bridge the electrical gap so to speak.

James
 
Originally posted by Marc
Blzebub,
I would So disagree with your opinion. You have never heard the DBLs if you have not heard them in this mutation. The sound is So far ahead of what you have heard any Naim speaker do active or otherwise...I have heard ACTs and I would humbly suggest you come on over to Rons or my house for a listen.
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No worries this end, it was only a suggestion to save a lot of time, money & effort on your part. It's a bit of a long way from the UK, but thank you for the invitation nonetheless.
 
A few days ago I got to hear the effect of a single Cardas cap in the HF section of a crossover network and compare it to an identical speaker (plus/minus 0.25 dB on frequency sweep) with my current reference Theta Audiocap. The Cardas capped x/o'd speaker sounded in an entirely different league in terms of purity, extension, lack of vocal hardness, coherence and instrument seperation. A far, far, FAR bigger difference than that between the Solen and Hovland caps which I am (and do) able to compare on a nightly basis at the flip of a switch. I have put in an order to the 8 caps I need to redo my tweeter section ($1300 in the values I need). I should have them in and installed in about a week or so.

James, as sophisticated as your E-speakers are, you NEED to try some of these out. I'm not so sure why they sound so good.... frequency sweeps all the way up to 100k failed to show a single measurable difference between them and the Solens.
 
Ron,

I did try some 'better' caps (Sonicaps) in the E-IIIs, both in the HP filter and the bandpass as well. I noted the 'improvements' in terms of a cleaner treble, more 'blackness' and seemingly better transparency - but somehow I did not enjoy the music nearly as much. I had the Sonicaps in circuit for almost a month. When I put the Solens back in, I was flabergasted how much more coherence I got. It just seemed more like music and less like a super-detailed hi-fi system.

Based on that episode, I have not felt the inclination to try other super-capacitors and would rather focus on getting my designs to sound right on Solen caps. Another factor in that decision to stay with Solen is price. I have a drawer-full of recycled capacitors and if those were Hovlands or Cardas caps, I'd have to sell the car to fund my hobby.

BTW, have you considered a capacitor-less crossover? Something like what the SF Extrema used could be interesting (but a hellava driving load and waste of power) and avoid the flavouring effect of capacitors.

James
 
"I have put in an order to the 8 caps I need to redo my tweeter section ($1300 in the values I need)."

:eek:

Mr Tibbs
 
Wouldn't it be worth considering designing a active crossover that mimics the transfer function of your deluxe passive crossover?

You could then use lower power (and so presumably cheaper) versions of the same components you are advocating for the deluxe passive. Presumably you would also get some of the benefits of active drive (better driver damping etc) and save some money.

Er, just a thought.......
 
Originally posted by Martin M
Wouldn't it be worth considering designing a active crossover that mimics the transfer function of your deluxe passive crossover?
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The custom passive crossover is designed to incorporate the reactive characteristics of the drive units as part of the overall crossover circuit. If you made it active, then you would be disassociating the drivers and external components, so the overall design would need to be completely different.

Besides, this crossover costs about $1000US, which should be much cheaper than an active crossover with power supply, plus 4 extra channels of amplification.

-=> Mike Hanson <=-
 
Hi Mike,

the overall design would need to be completely different
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Yes, but the overall transfer function would be the same.

Besides, this crossover costs about $1000US
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I believe $2500 with the merely extremely good components. Quite a bit more with the 'stunners'.

which should be much cheaper than an active crossover with power supply, plus 4 extra channels of amplification
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I was laboring under the impression that Ron had the extra amplification already.

I guess all I was saying that it may be worth re-considering the comparitive cost/benefit of the ultimate passive crossover vs an equivalent quality and function active crossover when you already have the extra amplifiers lying around.

Either way, it makes a fascinating read.
 
I do have an unused Snaxo, Supercap and 4x135s around. I know that it is possible to have my Snaxo retuned to provide a lot closer to the ideal transfer function than the standard Bessel 3-rd order that it currently does, although the all-important phase characteristics may be rather poorer. Also I know that a mix of 1x500 and 4x135s is lopsided and ultimately doomed to failure. Right now I am having a far better overall performance than any active system I have owned/heard. By the time I get done I will have a crossover worth circa $4000, which is still less than one supercap. Sometimes less is more.

If Naim ever offers a 500-series Snaxo that offers a less generic transfer function I would consider re-activating.
 
Ron, I have little doubt that you have improved your DBLs with all the work which you have done. One of the problems with the DBL, however, is the midrange driver, which isn't all that good. No amount of tinkering around the back is going to alter this, sadly. If you can get a demo of the ATC 150A (preferably on some Mana stands) you will perhaps see where I'm coming from.
 
I sat in an anechoic chamber, blind-testing crappy old Naim midrange drivers for three and a half weeks.
 
Actually the midrange driver is much better than the tweeter and in some ways even better than the far more expensive ATC-sourced woofer. But I have already ordered a pair of custom built midrange drivers (made of a randomly dispersed composite of Kevlar, carbon fiber and resin) with an aluminum voice coil, gold plated copper windings, a large linear x-max,a cast basket and near linear frequency response to replace the standard midrange drivers. I have no doubt that these will significantly improve the articulation, transient response, linearity and inner detail. At this point the speaker will no longer be a DBL, although if SBLs can go through driver upgrades and still be considered SBLs, then why not DBLs? The leaf driver decoupling will (for now) still remain preserved. Once installed I will have to re-run another set of SPL and electromechanical impedence sweeps and readjust the bandpass section of the crossover accordingly through CAD modelling.

Just as some people have completely redone 32.5, 102 and CD3s to great effect through scrupulous engineering, premium components and fortification of weak spots, the same is do-able with the DBLs. Oh yes I kan.

If I get a set of ATC speakers they would then be subjected to the same scrutiny as my DBLs, and probably end up no better than my final goal.
 
I admire your fortitude and dedication, and completely approve of your ditching the tired old Naim midranges. Best o' luck.
 
"I admire your fortitude and dedication"

Me too. There is something very satisfying in studying the workings of a piece of high end kit, then finding ways of eliminating the compromises.

Despite what you're hearing now, your ATC's are no different, Bub. For instance, I'll bet those active crossovers are nothing special :)

Food for thought?

Mr Tibbs
 
Ron,

"But I have already ordered a pair of custom built midrange drivers (made of a randomly dispersed composite of Kevlar, carbon fiber and resin) with an aluminum voice coil, gold plated copper windings, a large linear x-max,a cast basket and near linear frequency response to replace the standard midrange drivers."

A purpose built midrange driver does not need high power handling nor a large x-max. In fact, +/- 3mm is more than enough unless you are crossing much below 200Hz.

Also, what would be the point of gold plating on the copper windings other than to add weight, which is the last thing you want in the moving mass of a responsive and dynamic driver.

James
 
Originally posted by Mr Tibbs
...your ATC's are no different, Bub. For instance, I'll bet those active crossovers are nothing special :)
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I'm sure you are right, well, I'm not actually, but I'll take your word for it. The ATC amplifiers were described by a friend as "agricultural".

It's the design which is elegant, and the drivers and cabinets are very good, but anything can be improved upon.
 
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