AR 4x vs 4xa Tweeters?

[JonL]

I've got a pair of AR 4x speakers with one non-AR tweeter. I believe the 4x and 4xa differ only in their tweeters (not sure about crossover). Another AKer has a pair of 4xa tweeters available. I am looking for opinions/advice: should I look for one or two original 4x tweeters, or convert my speakers to 4xa's? Anyone have any comments on the differences in sound quality between the two?

 

[gkimeng]

I've got a pair of AR 4x speakers with one non-AR tweeter. I believe the 4x and 4xa differ only in their tweeters (not sure about crossover). Another AKer has a pair of 4xa tweeters available. I am looking for opinions/advice: should I look for one or two original 4x tweeters, or convert my speakers to 4xa's? Anyone have any comments on the differences in sound quality between the two?

I would go with the 4xa tweeters, which are the same Roy Allison-designed cone/dome combo units that were used in the AR6, 7 and the MST-2 (among others). They have a wider dispersion than the earlier cone-only 4/4x tweeter, which can be rather "beamy," though not as wide as the domes on the bigger ARs. Some people think the 4xa unit has a brighter sound than the earlier model, but IMO what they're really noticing is that it produces a wider "sweet spot."

 

[RoyC]

I've got a pair of AR 4x speakers with one non-AR tweeter. I believe the 4x and 4xa differ only in their tweeters (not sure about crossover). Another AKer has a pair of 4xa tweeters available. I am looking for opinions/advice: should I look for one or two original 4x tweeters, or convert my speakers to 4xa's? Anyone have any comments on the differences in sound quality between the two?

The 4xa tweeter is a good, somewhat later, AR tweeter (also used in the AR-6 and others), but the 4x crossover point is too low for it to be used in that model.

Roy

 

[JonL]

Can the crossover point be changed with a capacitor change, or is the inductor also wrong? In other words, is it practical to modify my existing crossover?

 

[gkimeng]

Can the crossover point be changed with a capacitor change, or is the inductor also wrong? In other words, is it practical to modify my existing crossover?

I don't think I've ever seen a 4xa schematic anywhere. The crossover point is 1600 Hz compared to 1200 Hz for the 4x.

The AR-6, which uses the same drivers in a different cabinet, crosses at 1500 and uses a 10uF tweeter cap vs the 20uF cap in the 4x. It has a different inductor on the woofer for the US models (.88 mH vs 1.2 mH in the 4x), but no woofer inductor at all in the Euro model.

There's not a whole lot in the crossovers for these. If it was me, I'd order some caps and coils from PE and start playing around with them.

 

[JonL]

Oh boy... seems like I'm gonna start learning about crossovers now. Just what I need... another sub-hobby!
Thanks for the info.
Jon

 

[Zilch]

AR4x studies with a bunch of tweeter/crossover options here:

http://www.audiokarma.org/forums/showthread.php?t=123113

Woofers, too:

 

[JonL]

Thanks for the link. I've read that thread a few times actually, but haven't really dug in yet to grasp everything (anything?) that's there. I don't really have a use for the AR's right now, they will become my office speakers sometime when I have finally refurbed another amp or receiver. I was hoping that the 4Xa tweeters might be an easy way to retain the basic AR sound while gaining a bit of an improvement. I think I have the non-cross-hatch woofers (that should be better in terms of bass extension from what I've read), and perhaps the best approach then would be to purchase those $12 P.E. tweeters and build a new crossover... I think that thread had some designs. In the meantime I'm going to stick my head back in the sand and not think about this for a while!