AR5 midrange help, please

[ctjetta]

I've been looking almost a year for a pair of midranges for my AR5 cabinets. Had I known how unlikely it would be to find AR5 midranges I never would have picked up the cabinets for cheap. Everything else to make these functioning speakers is a small fortune. But, I'm all in now. 

Having said all that, I had read in a posting or two here, somewhere, that one could substitute AR 3 midranges with the addition of appropriate resistors. I purchased a pair of new "AR3", et al, midranges. Has number printed on back- 12100103 over 1718. They're all black, like later model AR midranges, but they fit the hole in my cabinet. So, I have that going for me!

So, now these are 3.2 ohms- can any one suggest the resistors I should acquire to make these work properly? 

Then it's on to new pots and recapping the crossover.  And new/refurbished grilles.

in my opinion, never let someone sell you AR5 cabinets cheap. They're not really doing you any favors.

[Aadams]

CTJetta

This thread.  Read the RoyC posts.  Ideally, you must add enough resistance to achieve 5 ohms.

 

[ctjetta]

Thank you!

[JKent]

5 hours ago, ctjetta said:

I purchased a pair of new "AR3", et al, midranges.

AR-3a? The 3 mids aren't the same.

[Dchristie]

HI Mark, sounds like you may have bought a new pair of generic midrange domes from one of the vendors selling them ( Simply Speakers) or those sold by AB Tech Services They have the same number as you quoted and are listed for use in AR 3, 3a, and several other AR  models using the 1.5 dome. I know that you can add resistance to the older, classic,  AR 3a midrange drivers and adapt them for use  in the AR 5 but Roy will have to confirm whether or not the 12100103 models are also acceptable . They may not have the same sonic character of the original  1.5 inch domes and I am not sure the xover would work for this model  without some additional tweaking as well.

But, in any case , since you have them already, add a 2 ohm resistor to each and see how they sound in your AR 5s. 

[Aadams]

7 hours ago, Dchristie said:

HI Mark, sounds like you may have bought a new pair of generic midrange domes

Good catch. I can't find it but somewhere in this forum is a thread in which RoyC discusses backward compatibility of all the AR dome mids.  IIRC the summation is all of the domes are backward compatible but the screened domes can be a drop in an replacement, including all the way back to the AR3 if you are willing to make crossover changes.  There was no discussion of after market domes.  If I were caught in this situation and could not find an original dome I would speak with Pete B about his new replacement integrated tweet/mid which might be ready for a real world application. See below:

 

Adams

[ctjetta]

I appreciate your suggestion of alternate an solution to my midrange issue, but, as I already own these dome midranges at a not insubstantial cost (sigh), I will have to make these work as best I can.

So, what power rating should I look for in this 2 ohm resistor? Does any one know where to best find this particular resistor- PE, Mouser, Digikey . . . ?

Edit- Found good supply of resistors at Madisound- still, what is considered minimum value for power, 10W,  20W, more? I have no basis of knowledge for this.

And as I'll now be ordering new caps will I be looking for different values for the midrange portion of the crossover?

It seems with these 5's it's always two steps forward, one step back.

I really do appreciate all y'all's help.

[Dchristie]

Mark, 10 watt resistors should be fine. I have used Dayton Audio-Grade Precision  resistors as well as other brands with equal success. As far as the xover  mods go, without any solid info from Roy or someone else on specifically using the 12100103 mids in your AR 5 application, I would just try the mids with the resistance added in the standard AR 5 crossover xover and see how it sounds to you.  You just might find it to be adequate for your needs at this time.

[Stimpy]

Those look like the same midrange domes that are used in the AR303's, 302's, and 338's.  Any way to compare crossovers, for the differences?

 

 

[RoyC]

ctjetta's mid has a slightly smaller magnet than the original AR mid, but the construction is otherwise very similar. It is less sensitive than AR's 4 ohm mids, but should work acceptably in the AR-5. As suggested above, I would use them with 2 ohm resistors (rated 10 watts or greater). I would also use them with 8 ohm L-pads (as is) for a little extra output, instead of the original pots.

Roy

[ctjetta]

9 hours ago, RoyC said:

ctjetta's mid has a slightly smaller magnet than the original AR mid, but the construction is otherwise very similar. It is less sensitive than AR's 4 ohm mids, but should work acceptably in the AR-5. As suggested above, I would use them with 2 ohm resistors (rated 10 watts or greater). I would also use them with 8 ohm L-pads (as is) for a little extra output, instead of the original pots.

Roy

Roy,

Thank you so much for your recommendations. The suggestion of the L-pad is appreciated as I would have purchased 15 ohm pots to replace the severely corroded units I currently have.

Now, I just need to gather the appropriate caps, resistors, two 15 ohm pots (tweeters), two 8 ohm L-pads (midrange) and I can put this project to bed. 

I'm really looking forward to putting these in play.

[ctjetta]

OK, So I just done a little CSP research re: L-pads, and I now have more questions. Go figure.

I saw where it was recommended to use a 25 ohm resistor when using an L-pad- is that still the case for use with my midrange application?

And, as opposed to my plan of using pots for the tweeters (for originality's sake, though why at this point . . .) and L-pads for the midranges it was suggested not mix the two types of controls. Is this still still true? Would I then use a 16 ohm version for the tweeters (which by the way, sigh, are 3a tweeters supplied by Roy with the appropriate add-ons) vs the 8 ohm for the midranges? And then what of that 25 ohm resistor thing?

I'm beginning to believe that AR5's are the red- headed stepchildren of the AR product line. Bu, damn it, I'm going to love them as my own!

[Aadams]

43 minutes ago, ctjetta said:

I'm beginning to believe that AR5's are the red- headed stepchildren of the AR product line.

Now 50 years after its introduction, the AR5 is IMO the most modern sounding of all the classic models.   The rare AR12,  AR92, AR 302 and especially the 338, which I have never seen for sale, should be competitive with the best sounding modern speakers for home use.  I would not have said this 2 years ago but I didn't know then what I know now.

Adams

[JKent]

1 hour ago, ctjetta said:

I now have more questions. Go figure.

Since you got the tweets from Roy and he's really the expert on all the things you asked about, just send him a PM.

[RoyC]

2 hours ago, ctjetta said:

OK, So I just done a little CSP research re: L-pads, and I now have more questions. Go figure.

I saw where it was recommended to use a 25 ohm resistor when using an L-pad- is that still the case for use with my midrange application?

And, as opposed to my plan of using pots for the tweeters (for originality's sake, though why at this point . . .) and L-pads for the midranges it was suggested not mix the two types of controls. Is this still still true? Would I then use a 16 ohm version for the tweeters (which by the way, sigh, are 3a tweeters supplied by Roy with the appropriate add-ons) vs the 8 ohm for the midranges? And then what of that 25 ohm resistor thing?

I'm beginning to believe that AR5's are the red- headed stepchildren of the AR product line. Bu, damn it, I'm going to love them as my own!

In my post above I stated to use 8 ohm L-pads as is with the replacement mids. Using the additional 25 ohm resistor for the L-pads would defeat the purpose of the recommendation.

Since your tweeters and mids are not original to the AR-5, I recommend using all 8 ohm (not 16 ohm) L-pads without the 25 ohm resistor for the tweeters and mids. As Kent suggested, send me a PM or an email if you need further assistance.

Roy

[ctjetta]

3 hours ago, Aadams said:

Now 50 years after its introduction, the AR5 is IMO the most modern sounding of all the classic models.   The rare AR12,  AR92, AR 302 and especially the 338, which I have never seen for sale, should be competitive with the best sounding modern speakers for home use.  I would not have said this 2 years ago but I didn't know then what I know now.

Adams

Though I had never heard of AR5's prior to purchasing the cabinets (,AR2's, AR3's, AR4's and many later ones I was aware of, if not familiar), it was the warm reviews of the AR5 that has encouraged me to continue on with the effort though it seems like forever before the job will be done.

So, though it may seem as if I am disparaging of the AR5, it's more that I was unaware of the investment required to restore these- I originally purchased the cabinets for $35 because the seller wanted to move them with the 4x cabinets he was selling for $15. Sounded good to me! I didn't know the midranges where near unobtanium. Oh, and then I learned of the front vs rear wiring versions of these, and also the tweeters (almost as difficult to find).

OK, I've cobbled together the parts that will give me a reasonable facsimile of an AR5- thank you, RoyC and PeteB. Would I prefer all original? Sure, but what's the point if I never get there.

And I appreciate all those who aimed to help. CSP is truly the finest community when it comes to member support.

I think I now have a clearer concept of what's required to finish the crossover and controls and I am really looking forward to these being the prime members of my speaker collection.

I will probably need more help. Just so ya know.

[Pete B]

Since I sold you the old 2ax woofers that I had, I came across some of my old posts where

I mention that while the Fc measured in box looked correct, Qtc did not for those woofers

and so there might be a problem with them.  I'd be happy to measure them for you and take

them back with a refund if they are not right - just let me know.

I believe that most of the 8 ohm 10" woofers used in ARs 2-way and 3way designs should 

work fine in the 5 since all that I've seen spec 56 Hz Fc and a Qtc of 1.15.

[Pete B]

I plan to do a tweeter-mid plate for the AR-5, just have to get around to it.

Try to enjoy the journey, assuming it is a hobby for you.

[Dchristie]

Hi Mark, the really only major sonic difference between the components you have ( woofer, mids, tweeters) and the original AR components are the generic midranges since they were later generation mids compared to the earlier ones. There should be no difference in the sound when using  the 4 ohm, AR 3a tweeters in place  of the 8 ohm, AR 5 tweeters as long as  you adjust the crossover for the 3a  tweeter and use a 6 uf cap  compared to 4 uf for the 8 ohm tweeter in the AR 5. The tweeters both crossover at 5000 hz for both models. You  may have to slightly decrease the L pad for the 4 ohm tweeter but sonically, I  think they are the same. And, if Pete's woofer checks out as well, then you are good to go . The level controls allow one to balance everything out in the mids and highs and I doubt anyone could tell the difference between AR 3a mids and tweeters compared to AR 5 mids and tweeters once they have been adjusted via the level controls. So you are really getting close to the classic AR 5 sound so don't despair. As Pete said, enjoy the Hobby. Even with the generic midranges, I believe you will have nice sounding speakers once you have everything put together. 

[ctjetta]

 

On 3/5/2019 at 6:14 PM, Pete B said:

Since I sold you the old 2ax woofers that I had, I came across some of my old posts where

I mention that while the Fc measured in box looked correct, Qtc did not for those woofers

and so there might be a problem with them.  I'd be happy to measure them for you and take

them back with a refund if they are not right - just let me know.

I believe that most of the 8 ohm 10" woofers used in ARs 2-way and 3way designs should 

work fine in the 5 since all that I've seen spec 56 Hz Fc and a Qtc of 1.15.

Pete B, I found this schematic for the AR5 crossover elsewhere on CSP. The reason I make note of it is that it says it's for the AR5 with the ceramic magnet woofer. Would this woofer be different than the AR2ax woofer you provided which has a ceramic magnet?

AR5_schematic.pdf

[Pete B]

I did not check that schematic carefully but it looks like the only one I've seen for the AR-5.

I'm certainly no expert on the AR-5 so others should also comment.

[ra.ra]

This has been posted here before, but I find each of these schematics far easier to use than the one posted by ctjetta. Although these diagrams show different values for the midrange resistor (I can never remember which one is accurate ), this issue is somewhat irrelevant since this resistor is the small nichrome wire and will not require replacement.

The pic attached shows an early AR-5 woofer with the alnico slug magnet, but I'm pretty certain that the crossover components remained the same regardless of which type of magnet is found on the woofer.

(Edit: just for clarification, RoyC commented in another thread that the correct value for the nichrome wire on the mid driver is 1.5 ohms) 

[AR55]

If your are still looking for midranges for your AR-5's, a pair is up for sale on eBay:

https://www.ebay.com/itm/Acoustic-Research-AR5-Midrange-Vintage-Speakers-Sound-Great-Test-Great-Long-Lead/123683251431?hash=item1ccc18a4e7:g:CfwAAOSwZGJcg2Wm

[ctjetta]

On 3/10/2019 at 3:09 PM, AR55 said:

If your are still looking for midranges for your AR-5's, a pair is up for sale on eBay:

https://www.ebay.com/itm/Acoustic-Research-AR5-Midrange-Vintage-Speakers-Sound-Great-Test-Great-Long-Lead/123683251431?hash=item1ccc18a4e7:g:CfwAAOSwZGJcg2Wm

 

Thanks for the heads up. Given what I've already spent on the AR replacement mids, if i'm going to replace them with originals, as I would like to do, they would have to better examples than those pair. For one thing, mine are rear wired. I know there's a work around but I'm not currently in a position to have to spend the extra dough then have to jerry rig drivers. I'd rather someone who needs front wired mids have them.

If a good example of the proper drivers comes along I can then opt to make the effort.

Again, thanks.