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AR-4x woofer response document source?


Carlspeak

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I came across the attached document recently. It looks very much like an original Acoustic Research response chart and I would like to confirm this.

I can't remenber how or where I obtained it. I looked in the library and it's not there. Sadly, there's very little information on the 4x.

There also is a similar tweeter response chart. I did some 4x thread searches here and over at AK and couldn't find it.

Can anyone help confirm this is indeed an original AR document?

post-100237-1224937570.jpg

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Thanks. I suspected it was someone like TT or Roy C. or John O.

Could you give a link to that TT post you referred to?

Hi Carl,

After a great deal of searching, just for you ;-), I found Tom Tyson's posting I think you wanted.

Unfortunately, the links to the diagrams have not been updated and failed when I tried them. Of course, the curves above are the ones refered to in the post.

(should you want to find the original posting, you could use a unique phrase in the text to search)

<<<<<<

tysontom

View Member Profile Aug 29 2005, 02:53 AM Post #4

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Group: Members

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Joined: 30-November 99

Member No.: 100,160

>I have never seen published anywhere FR numbers for any of

>the old single-digit AR speakers. I assume AR must have had a

>policy of not quoting such things in advertising, brochures,

>etc. I could have missed it, but I've not seen figures in the

>library either.

>

>I'm most interested in the 4x. This is a speaker, perhaps

>because of it's diminutive size, that just never fails to

>astonish me with it's sound every time I listen. I just wonder

>what numbers are attached to the sounds I so enjoy.

Ed, it was AR policy to publish a full family of response curves and performance data for each and every speaker they made up through at least the mid-1970s. This information was available to anyone, simply "for the asking." AR did not just throw out numbers; they published curves with measurements made on instrument calibration traceable to the US Bureau of Standards. For example, AR published both on- and off-axis anechoic frequency-response curves for the AR-4x as well as harmonic-distortion data. Later data included impedance and acoustic-power-response data as well. To my knowledge, AR was the *only* "mainstream" loudspeaker manufacturer to publish this level of information for a loudspeaker during that time period.

The AR-4x has a very flat measured response, both on- and off-axis. It also has smooth, uniform response off axis, and AR considered dispersion to be extremely important. Flat response on-axis is one thing; uniform response off-axis is quite another.

http://www.classicspeakerpages.net/dc/user_files/579.jpg

AR-4x Tweeter anechoic response curves -- 1965

http://www.classicspeakerpages.net/dc/user_files/581.jpg

AR-4x Woofer free-field response curves -- 1965

Hope this information helps.

--Tom Tyson

<<<<<<

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Thanks a bunch for spending the time to find the post. I have yet to see a respose curve for any COMPLETE AR speaker. What I find all the time are curves for the drivers, but for some reason they didn't 'put it all together' for public viewing. Tome aludes to their having published finished loudspeaker response curves, but I haven't seen any.

I've been doing some nearfield testing of a 4x woofer and get a slightly different curve with a larger hump at the low end. I'll try and do a 180 baffle board test also to see if I can get closer to what AR published.

In any case, the PDF you attached earlier belongs in the library.

Thanks again.

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Ed, it was AR policy to publish a full family of response curves and performance data for each and every speaker they made up through at least the mid-1970s. This information was available to anyone, simply "for the asking." AR did not just throw out numbers; they published curves with measurements made on instrument calibration traceable to the US Bureau of Standards. For example, AR published both on- and off-axis anechoic frequency-response curves for the AR-4x as well as harmonic-distortion data. Later data included impedance and acoustic-power-response data as well. To my knowledge, AR was the *only* "mainstream" loudspeaker manufacturer to publish this level of information for a loudspeaker during that time period.

Hope this information helps.

--Tom Tyson

<<<<<<

Hi there;

My big brother had original AR blueprints of the AR-3A Improved and the AR-LST's.

These were accidently dumpstered about a decade ago.

In hindsight it is a shame that blueprints were not provided with each individual speaker system along with their spec sheets.

I know, cost.

They were available for the asking, as were the spec sheets and promo literature and booklets, all at no charge to the end user.

A very confidant manufacturer in their product line, with it's superior customer service program at that time.

I feel fortunate to having been led down this AR garden path with my second system and later ones.

I felt very supported by my many, sometimes silly, inquiries to AR, which were most often answered personally by none other than, Roy Allison.

A great company during that classic period, bar none.

Vern

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