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upgrading speaker crossovers & tuning

I recently picked up a pair of Snell type A's (orginals) in near perfect condition. The foams were recently upgraded.

I have them hooked up to 60 watts of tube power while I search for the preamp & power that will drive them for real.

At this point the speakers sound fine (barring the lack of the right power), but I'm considering having the crossovers upgraded. I found a gent out on the east coast that has redone one pair of Type A crossovers with apparently very good results. (see bottom of webpage --> http://classicloudspeakerservices.com/gallery.html#crossover)

There is one point I'm sticking on & I hope someone here can help me out. It's said that Peter Snell 'tuned' each set of speakers prior to them being available for sale. I hear this is still the practice today.

One description of the tuning I've run across is: "A highly specialised set up process, which matches the crossover to the drivers in a way that not only aligns the drivers in the frequency and time domain, but also affects the dispersion."

My question is whether the crossover upgrades will basically negate the tuning that Snell did. Is this 'tuning' marketing hype or something real that shouldn't be lost? As I said, the speakers currently sound very nice, but I have to believe the capacitors and resistors might be weak just from age alone on top of being obsolete in design.

If the tuning is lost by the upgrade, can I get it back? I'm told there are variable resistors in the crossover that may be the tuning mechanism & that the upgrade doesn't touch these. Would this maintain the tuning in spite of the upgrade?

Lots of questions I know...

thanks
fishboat

Showing 2 responses by jeffreybehr

jeffreybehr's avatar
jeffreybehr
805 posts
 
I disagree with Unsound. I agree with Fischboat in that the quality of the caps and resistors probably leave a LOT to be desired.

I certainly don't disbelieve that Richard Snell personally tuned each system. I THINK you can retain that by matching the replacement resistor and cap values to within 1%. I'd sure take out any variable resistors and replace with good fixed resistors. The Mills 12W. NI WWs sold by Percy and Sonic Craft are great for crossovers, and probably I'd use SoniCap-1s to replace all caps*. If there are inductors in series with the signal (other than in the bass section), as in a MR low-pass filter, I'd use the AlphaCores, here http://www.soniccraft.com/alphacore_inductors.htm .

Good luck.

* except any shunt cap in the woofer section.
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jeffreybehr's avatar
jeffreybehr
805 posts
 
Raul's comments make sense to me. I'm no GEA but I've heard differences in caps and resistors, the latter between the cheapest sand-type and the Mills NI WWs. I've replaced the usual 16g. inductors in series with the MR drivers of my Eminent Tech. 8s with Solo copperfoils, and the whole topend sounds better, but I did other things too.

Tuning with and later replacing variable resistors is a good idea.
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