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AR3a tweeter polarity


Guest dogmeninreno

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Guest dogmeninreno

I recall some time ago that there was some ? regarding the tweeter being connected in reverse polarity to the mid and woofer by AR factory for a smoother response. Can someone verify the reason that they did this? Thanks Dale..

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>I recall some time ago that there was some ? regarding the

>tweeter being connected in reverse polarity to the mid and

>woofer by AR factory for a smoother response. Can someone

>verify the reason that they did this? Thanks Dale..

Dale,

In the early 1960s -- probably around 1960 or 1961 -- AR engineers noticed (in their anechoic chamber) some problems, and suspected it was a phase problem. The polarity of the woofer was reversed temporarily and the transition through the crossover improved. Subsequently, out of the anechoic chamber (this was prior to AR's development of their reverberant-test chamber), the engineers connected a dpdt switch at one end of a long cable to accomplish the same thing remotely, while listening to pink noise and music. Using the remote switch, the midrange was thrown in and out of DC phase alternately, and the difference was indeed audible -- not surprising considering the fairly low crossover and the small distance between the two drivers. It was agreed that the DC-out-of-phase condition was more natural. The tweeter polarity, however, made no audible difference and it was left alone.

Today the choice would be much easier to make because of the availability of test sets that make it simple to measure power output through the crossover region.

--Tom Tyson

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Guest dogmeninreno

Thanks again Tom...By the way, are the AR11 woofers interchangable with the AR3a woofers? I have a friend with a bad AR11 woofer and all I have is AR3 and AR3a woofers right now..Dale

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>.By the way, are the AR11 woofers

>interchangable with the AR3a woofers? I have a friend with a

>bad AR11 woofer and all I have is AR3 and AR3a woofers right

>now..Dale

Yes. All Classic-ADD-Vertical series AR 12" woofers (remember, NEVER call them 11"!) are 4-ohm units, designed to the same performance standards. While the materials and production methods changed and improved over the years, the drivers themselves can be considered to be, for all practical purposes, interchangeable.

As a matter of fact, AR-3a and AR-11 production overlapped for a short time (1975-1976), so the exact same woofer (and 1 1/2" midrange) was being used in both speakers. The tweeter, crossover, and cabinets were different, however.

So I would feel quite comfortable in using a mid-to-late generation 3a woofer in an 11.

Steve F.

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Guest dogmeninreno

>>.By the way, are the AR11 woofers

>>interchangable with the AR3a woofers? I have a friend with a

>>bad AR11 woofer and all I have is AR3 and AR3a woofers right

>>now..Dale

>

>Yes. All Classic-ADD-Vertical series AR 12" woofers (remember,

>NEVER call them 11"!) are 4-ohm units, designed to the same

>performance standards. While the materials and production

>methods changed and improved over the years, the drivers

>themselves can be considered to be, for all practical

>purposes, interchangeable.

>

>As a matter of fact, AR-3a and AR-11 production overlapped for

>a short time (1975-1976), so the exact same woofer (and 1 1/2"

>midrange) was being used in both speakers. The tweeter,

>crossover, and cabinets were different, however.

>

>So I would feel quite comfortable in using a mid-to-late

>generation 3a woofer in an 11.

>

Thanks Steve, that answers my question. My friend will be pleased! Dale

>Steve F.

>

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