What's the frequency range of a 2ax midrange?

[genek]

Anyone done a sweep of this driver? What are its low and high ends when driven raw without a crossover?

[dynaco_dan]

Anyone done a sweep of this driver? What are its low and high ends when driven raw without a crossover?

Hi there;

Just a mention that this 3 1/2" driver was also used as the AR-4, not the AR-4X, early AR-1X and early AR-2X tweeters as well.

Quite a feat for it's cost, bought from CTS and then modified by AR with the fiberglas and metal screen cover.

When AR ran out of the Altec 8" mid/tweeter drivers, used in the AR-1 speaker system, the warantee depots were advised to use the AR-4 tweeter with the adapter plate that they provided, I never saw either the old 8" tweeter or the new plate adapter.

I remember this detail because I saw a hand written note where the word, "Altex", not, "Altec", was used.

This message must have come via phone call from either AR or A. C. Simmons and Sons in Canada, it sounds the same, only plural.

These can be had for $5.00 - $10.00 each on ebay very often.

I picked up 5 for $.99 plus S&H.

The CTS 3 1/2" was superceded by the 2 1/2" AR produced tweeter, which had slightly greater dispersion, transparency and power handling capabilities.

[genek]

So does that mean you don't know...?

[tysontom]

So does that mean you don't know...?

Genek,

I believe he was trying to describe the 3-1/2-inch midrange and its application, which he did quite well. It was an documented fine-performing driver in every respect.

I have attached the frequency-response measurements, on- and off-axis, as measured in an anechoic chamber by AR several years ago. It was measured with the crossover, since this is the best way to measure such a driver that is optimized for a particular application. The frequency response was flat within a couple of dB from approximately 2400 Hz out to 13000 Hz, on axis, and this should be considered its pass band. It was particularly linear and smooth out in the 4-10K region, and the uncolored sound of the AR speakers that used this driver is very evident. Unless you have an anechoic chamber, a gaited-measurement system or ground-plane setup, you will be hard pressed to make a meaningful measurement of the raw driver. RTAs are unsuitable for fr testing, and close-miking doesn't apply to anything except low-frequency woofer measurements. I would therefore recommend that you use the AR measurement, and consider the crossover elements as important adjuncts to the performance of the driver.

--Tom Tyson

[genek]

I have attached the frequency-response measurements, on- and off-axis, as measured in an anechoic chamber by AR several years ago. It was measured with the crossover, since this is the best way to measure such a driver that is optimized for a particular application. The frequency response was flat within a couple of dB from approximately 2400 Hz out to 13000 Hz, on axis, and this should be considered its pass band. It was particularly linear and smooth out in the 4-10K region, and the uncolored sound of the AR speakers that used this driver is very evident. Unless you have an anechoic chamber, a gaited-measurement system or ground-plane setup, you will be hard pressed to make a meaningful measurement of the raw driver. RTAs are unsuitable for fr testing, and close-miking doesn't apply to anything except low-frequency woofer measurements. I would therefore recommend that you use the AR measurement, and consider the crossover elements as important adjuncts to the performance of the driver.

Thanks Tom. I have a bunch of these in a box and was wondering how short they might be of being usable as "full range" drivers. I'm thinking about surround speakers that only need to go down to around 200 Hz or so. I guess I'd still need some sort of a woofer.