AR 2x vs AR 2ax

[jlovda]

Is an AR 2x the same as a 2ax except there is no dome tweeter? Is the crossover on a 2x the same as a 2ax except there is no tweeter connection and no second rheostat? (same caps and coil). First I have poor hearing. Second I obtained a pair of 2ax speakers with beautiful cabinets for $10 but I have already spent about $100 for two replacement woofers, surrounds and cone cleaning chemicals. I have yet to buy new tweeters and xover components. I feel like I am chasing good money after bad. Any suggestions?

 

[ra.ra]

Yes, your assumptions of the speaker models are basically correct - - the 2x is a two-way and the 2ax is a three-way - - but it should also be noted that there are two versions of each speaker model. Early versions of each used a 6-screw cloth woofer surround, while later versions used a 4-screw foam surround woofer; also, the diameter of the baffle cut-out was different, so the woofers are not interchangeable. Further, early and late versions of each model also used different tweeters.

And yes, your notes about the crossovers seem correct as well. The 2ax, being a three-way, has an additional cap (4uF) and pot for the third driver, the HF tweeter.

Not sure why you are replacing drivers in the first place. Did you start this project with empty cabinets? Post some pics, perhaps that will assist you in getting the best responses for your project.

 

[jlovda]

Yes, your assumptions of the speaker models are basically correct - - the 2x is a two-way and the 2ax is a three-way - - but it should also be noted that there are two versions of each speaker model. Early versions of each used a 6-screw cloth woofer surround, while later versions used a 4-screw foam surround woofer; also, the diameter of the baffle cut-out was different, so the woofers are not interchangeable. Further, early and late versions of each model also used different tweeters.

And yes, your notes about the crossovers seem correct as well. The 2ax, being a three-way, has an additional cap (4uF) and pot for the third driver, the HF tweeter.

Not sure why you are replacing drivers in the first place. Did you start this project with empty cabinets? Post some pics, perhaps that will assist you in getting the best responses for your project.

My woofers have foam surrounds and four mounting holes. The speakers came with two Radio Shack 10" woofers. I assume the previous owner had woofers with rotted foam and either did not know or didn't want to bother refoaming. Both of the black paper dome tweeters have dents; one minor, one major although both work. The midranges work. I'm taking a wild guess that the straw that broke the camel's back was rheostats with dead spots. I have not removed them from the cabinet yet. The woofers are reasonably close to the AR originals looking at the T-S parameters on the RS website. One other problem is that I bought two original woofers with bad foam on ebay as-is but one has minor rub that I do not think can be corrected by shimming. That means another woofer and surround purchase somewhere. New tweeters and the required inductors would be another $40 from Parts Express. As you can see, I am beginning to contemplate refinishing the cabinets and selling them alone. The grilles had been redone and are beautiful. No logos. I was going to refurbish and flip them as I have two good sets of speakers but I will probably spend over $200 to complete the whole job.

 

[ra.ra]

Sounds like you know what you are doing, and who knows, maybe both of those replacement woofers will work out fine - - even the one with the rub may become re-aligned with a careful re-foam using shims. Not sure why you need new tweeters if both originals are working - - perhaps those dented domes can be remedied with a little creative suction. And if the original inductors are missing, of course they'll require replacement. And, as always, those pots most surely have developed some corrosion and will require some careful restoration or replacement.

Best of luck, keep us posted.

 

[jlovda]

The original woofer inductors are not missing. According to the experts here, the replacement dome tweeters from Parts Express require an inductor in parallel for optimum performance. This coil is glued to the magnet of the tweeter.

 

[ra.ra]

Oh, oh, now I think I understand. You must be talking about the Hi-Vi tweeter that fits the hole, and with the added inductor, pretty much replicates the original tweeter. Carry on.

 

[gkimeng]

The 2x two-way has a crossover frequency of 1200 Hz. The 2ax 3-way crosses at 1400 Hz and 5000 Hz.

The original tweeters in the 2x are the same ones used in the AR-4 and 4x.

The HiVi Q1r + inductor combination was calculated for replacing the 4 ohm dome tweeter in the AR-3a. Some people have used it in the 8 ohm 2ax and have reported satisfactory results, but to date we have not seen any actual measurements, so these reports are based solely on listening.

 

[ra.ra]

gkimeng is correct about the 2x later version (2-1/2" tweet, foam woof), with x-o at 1200 Hz - - this speaker uses the AR-4x tweet and should have a 20uF cap. The first pic attached shows this crossover, which should be similar to yours.

For information, the 2x early version (3-1/2" tweet, cloth woof) has its x-o at 2000 Hz and uses the AR-4 tweet with a 6uF cap. Second pic shows this version.

As would be expected, both of these AR-2x cap values and crossover frequencies match the applications where these tweeters are used in the corresponding smaller AR-4 and AR-4x models.

 

[jlovda]

Just looking at the pictures, the tweeter in the 2x looks identical to the midrange in the 2ax. Cone unit with fiberglass and a grille in front of it. The mid in the 2ax does not have a low pass inductor matched to it so it seems to be operating in tandem with the dome above 5khz. The midrange must naturally roll off somewhere near 10khz-15khz. If it was lower, there'd be no highs in the 2x.

By the way, I just refoamed my two woofers and the one with the rub works OK (pushing the dustcap) after shimming it and soaking the spider with acetone to reshape it. I saved almost $50!! I will put a 50 hz tone on it tomorrow to confirm its operation.

 

[RxDx]

Here's the FR of the late 2ax. Your speculation appears accurate.