AR11 midrange

[Guest]

Can anyone tell me if the midrange for an AR11 is the same unit used in the 3a.

[Guest Barrydor]

>Can anyone tell me if the midrange for an AR11 is the same

>unit used in the 3a.

It is of similar design, but it is not the same unit.

Barry

[Guest]

Thanks. I'll save my money and not bid on the one on Ebay. I currently need a mid for my 3a

[tysontom]

>>Can anyone tell me if the midrange for an AR11 is the same

>>unit used in the 3a.

>It is of similar design, but it is not the same unit.

>

>Barry

AR had as many as five 1-1/2" midrange units: one for the AR-58s; one for the AR-9 and AR-90; one for the AR-10Pi, AR-11, AR-3a and AR-LST; one for the "modified" AR-3; and one for 8-ohm AR-5 and AR-LST/2. The one for the AR-3a and the AR-10/AR-11 are actually the same unit, part no. 1200010-1, so you can use the AR-11 unit in the AR-3a. A few years into the production of the AR-10 and AR-11, the fiberglass under the wire screen was pink, and the screen itself was painted silver. Other than that, the driver was the same. Early 11's had the yellow fiberglass under the screen. However, all AR-11's were "back-wired" versions, so you will have to solder pigtails to the two eyelets on the front if your AR-3a is "hard-wired" to the tweeter terminal strip.

--Tom Tyson

[Guest SteveG]

Tom (and Others),

Tom indicates that the midrange for the AR5 was different from that for the 3a, 11 and LST. The AR% was a nominally 8 ohm speaker, but I had always thought that was because the woofer made the difference. The mid and tweeter of the AR5 have usually been characterized as exactly the same as for the 3a. But you are suggesting that they were in fact different, thus contribution to the difference in system impedance. Please confirm.

By the way, I awlways thought tweeter of 5 and 3a and 2ax were also the same. Not true??

Thanks

SteveG

[tysontom]

>Tom (and Others),

>

>Tom indicates that the midrange for the AR5 was different

>from that for the 3a, 11 and LST. The AR% was a nominally 8

>ohm speaker, but I had always thought that was because the

>woofer made the difference. The mid and tweeter of the AR5

>have usually been characterized as exactly the same as for

>the 3a. But you are suggesting that they were in fact

>different, thus contribution to the difference in system

>impedance. Please confirm.

>

>By the way, I awlways thought tweeter of 5 and 3a and 2ax

>were also the same. Not true??

>

>

>Thanks

>

>SteveG

Steve,

The AR-5 and AR-LST/2 1-1/2-inch-dome midrange unit was the same as the AR-3a/AR-11 except for impedance (AR-5 was 8-ohms-rated unit vs. the AR-3a's 4-ohm unit). They would be interchangeable except for differences in impedance. For example, the tonal balance would be adversely affected if you used an AR-3a midrange in an AR-5, and vice versa. I have heard of the AR-3a tweeter being installed in an AR-5 to increase the level, but not with good results, especially with respect to power-handling capability. Stick with the proper impedance if possible.

The 3/4-inch tweeter in the AR-2ax (post 1970), AR-5 LST/2 is also an 8-ohm unit. It, too, is physically identical to the AR-3a (and LST) 3/4-inch 4-ohm unit, but would be mismatched if interchanged.

The AR-58 and AR-9/AR-9LS, etc., had different drivers altogether.

Hope all this does not cloud the issue!

--Tom Tyson

[Guest SteveG]

Tom,

Thanks for the clarification. I had always thought that the mid and high drivers were identical between the 5 and 3a, and that the impedance difference arose from the woffer or crossover components. This is important to know that the mids and tweeters are NOT interchangable between these systems.

Are there any codes or other markers on the drivers that allow us to know which impedance they are???

Thanks SteveG

[tysontom]

>Tom,

>Thanks for the clarification. I had always thought that the

>mid and high drivers were identical between the 5 and 3a,

>and that the impedance difference arose from the woffer or

>crossover components. This is important to know that the

>mids and tweeters are NOT interchangable between these

>systems.

>

>Are there any codes or other markers on the drivers that

>allow us to know which impedance they are???

>

>Thanks SteveG

Steve,

If you can't find the part number on the back of the driver, you could actually measure the DC resistance of each driver. The DC resistance of the 4-ohm AR-11/AR-3a type midrange and tweeter is somewhere between 2.5 and 3.5 ohms; the DC resistance of the 8-ohm equivalents for the AR-5/LST/2 is on the order of 5.0 to 6.2 ohms. These resistances, of course, should be measured with the driver disconnected from the crossover.

--Tom Tyson

[fedeleluigi]

>

>If you can't find the part number on the back of the driver,

>you could actually measure the DC resistance of each driver.

> The DC resistance of the 4-ohm AR-11/AR-3a type midrange

>and tweeter is somewhere between 2.5 and 3.5 ohms; the DC

>resistance of the 8-ohm equivalents for the AR-5/LST/2 is on

>the order of 5.0 to 6.2 ohms. These resistances, of course,

>should be measured with the driver disconnected from the

>crossover.

>

>--Tom Tyson

Hi Tom

Thank you for all the answeers you give all of us in this forum. Your competence and help are very important and usefull to anyone who loves AR speakers.

I have some questions I hope you can answer.

Did the DC resistance of tweeters and midranges change during their production?

Could you be more precise with the DC resistance values becouse they are very usefull in order to understand if one driver is OK.

I mesured some AR tweeters (3a, 10 pi etc) and I noticed that there was a difference even of 0.2/0.3 ohms among them. Is that normal?

What difference can be considered normal?

I would like to use fuses to protect AR 3a, 2ax and 10 pi tweeters and midranges. Which values do I have to use?

Thank you  

Luigi Fedele