Speaker Phasing

[Guest dogmeninreno]

Help, Do you know how to check phasing of individual AR3a tweeters and mids if they are not marked? Dale

[Carlspeak]

Take a "D" cell battery and somehow get wires hooked up to the pos. and neg. side and connet each to the speaker terminals. When battery pos. is at the speaker positive the cone should move out. If it moves in then reverse the connection and there you will have it!

[Guest dogmeninreno]

Thanks for your reply! Can you detect movement on the AR tweeters and mids?? Dale

[Guest dogmeninreno]

Tried the D cell battery and cannot detect movment in the mids or tweeters. It has always worked on woofers. Help? Dale

[Guest dogmeninreno]

Carl, Makes sense to me. I should be carefull to be sure that the mids and tweeters are hooked up correctly series parallel - set one to + then - set2 and + to line + source? Thanks, Dale

[tysontom]

"Tried the D cell battery and cannot detect movment in the mids or tweeters. It has always worked on woofers. Help? Dale"

Are these AR-3a mid- and high-range drivers of the "hard-wired" variety, i.e., are they front-wired to the tweeter-terminal strip? They evidentally must be, as the newer versions (which began to appear in about 1973-74) are "back-wired" and use tab connectors that push onto on the rear of each driver, and these have fairly clear marking. It is possible that the "+" sticker is missing, however.

The reason I ask is that the earlier drivers usually had a "+" or red "a" marking on the front of the driver to denote polarity, and it sounds as though this is gone or missing from those drivers. One way to determine polarity is to look at the way they are wired to the four-lug terminal strip; the midrange and tweeter have a common center contact on the strip, and it is the positive side. Looking at the front face of the tweeter, the positive wire would be the wire on the right side of the dome (both wires are close together on the early tweeters). On the midrange side, the positive wire would be on the left side facing. Bear in mind, however, that after AR-3, Ser. No. 1417, AR reversed the polarity of the midrange and tweeter as wired to the strip.

--Tom Tyson

[Carlspeak]

There really is no need to bother wit the mids and tweeters becaluse they don't move nearly as much air as the woofers. It's the air movement at the lower frequencies that must be in phase so each woofer is pushing air out at the same time.

Carl, The SpeakerDoctor

[Guest dogmeninreno]

Carl, Yes these are the early ones, hardwired. I have a couple of extra bad tweeters that have the + mark on the left side of the driver lead as viewed from the front. The mids are as you indicate. The speakers are AR-LST's. Thanks, Dale in Reno.....

[tysontom]

>Carl, Yes these are the early ones, hardwired. I have a couple of extra bad tweeters that have the + mark on the left side of the driver lead as viewed from the front. The mids are as you indicate. The speakers are AR-LST's. Thanks, Dale in Reno.<

I pulled two tweeters from my NOS inventory, one old-style hard-wired version, and one new-style back-wired version. The old-style tweeter is marked positive on the right-side wire, and this wire is soldered to the center terminal of the front-panel tweeter-terminal strip. The newer tweeter (both are treated-paper domes) has the positive terminal on the left side when viewed from the front, with the AR logo mounted at the bottom. However, when mounted, that tweeter was positioned so that the positive wire was closest to the terminal strip. Remember, too, that AR furnished some "new-style" back-wired tweeters and midranges with pigtail leads to the front to mount on the tweeter-terminal strip on the early cabinet, if that's not confusing enough.

--Tom Tyson