AR 11 Diagram

[cARver]

I am working on my AR11 speakers and would like some clarification, explanation of the diagram listed on the The Classic Speaker Pages. I am by no means an expert and have pondered over this for some time. 

http://www.classicspeakerpages.net/library/acoustic_research/add_series_1975-1978/add_series_schematicsservic/ar-11_schematic.html

There are several difference between my speaker and the link above. I have also confirm my brother's speakers and a spare set of crossovers removed to have the same set up as mine.

The first difference are the resistors inside. 15, 10, 5, 3 and 1.5 ohm with this diagram showing 15, 3,3,1.5 and 1.5.

The second is an inductor (.44MH ?) on the same side as the 40uf cap in my speaker with the diagram showing on the opposite. 

The woofer circuit is a match to the diagram. 

One goal is to understand the paths for the mid and tweeter driver attenuation. 

I may be missing something, so please feel free to provide some clarity.

[Pete B]

I think that there were two or more revisions, that have been mentioned in other threads.

[cARver]

Thanks Pete. I've been looking for a while and haven't found them yet. If you see the threads please share. 

Thanks again!

[lARrybody]

I am thinking you may have the AR 11B model. My AR 11B had a single 120uf cap instead of the dual 72 uf and 50 uf caps in parallel of the original AR 11. I am sure the resister values may of been different too.

[Pete B]

Threads have been deleted here so I'm not sure if it is still around.

I think that it was in a thread were we discussed the AR-303 woofer as compared to the 11.

Here it is, links are often dead but you might try the Wayback machine or just looking up the 

docs in the library:

 

[Pete B]

Note that the schematic in your first post uses double pole switches, whereas your actual speaker

has single pole.  The two board version had double pole switches.

Here is a thread with pictures of member r_laski's rebuilds, nice work.  Also there are pictures

of the two board XO version with miniature switches rather than full sized - not sure if this helps:

 

[cARver]

Here is what I follow as the tweeter circuit. I moved the inductor to the tweeter on the diagram to clean things up. Looks like the tweeter is out of phase from the mid and woofer circuits.

I am a novice at this and tip my hat off to those of you who create these diagrams.

 

 

[fedeleluigi]

I've drawn the AR-11 MKII (B) crossover schematic. I've preferred to use old style types and drawing.

Hope it can be useful.

Luigi

 

 

 

 

Edited:  better drawing

[cARver]

2 hours ago, fedeleluigi said:

I've drawn the AR-11 MKII (B) crossover schematic. I've preferred to use old style types and drawing.

Hope it can be useful.

Luigi

Outstanding work!

I was close, but not quite. 

Can you please confirm 0/-3/-6 db signal path? See highlighted attachments in order.

Thanks again!

 

 

[fedeleluigi]

Yes, that's right!

Obviously,  tweeter and midrange switches are completely independent of each other and can be used to independently get different attenuation of sound pressure  in high- and mid-range frequencies.

Luigi

 

[cARver]

Yes, I did both to reduce the images.

These circuits are so much different to the 91 in my opinion. The 91 uses series resistance for all the attenuation where as this has parallel resistance for some attenuation?  

Thanks again!