Exploring potential improvements to AR9's while restoring

[VinylChef]

I have decided to take up the hobby of vintage speaker restoration (glory or insanity awaits!). My first attempt will be a pair of AR TSW-610's which needs new surrounds, caps (probably), and a replacement tweeter.

I've sourced the surrounds from ebay and an original tweeter from someone online and the caps have been chosen and purchased by a technician here in Sydney. This technician, who I have used for a lot of audio gear previously, has also kindly agreed to teach me how to do the restoration.

After these speakers, I will move onto some Polk Monitor 7c's, then a pair of B&W DM6's, then Infinity RSIII's, then a pair of AR9's. (All these speakers are stashed in my garage, awaiting my care.)

The AR9's will probably need the most work of all of them. They have been battered around a fair bit. I expect I'll need to strip the old veneer and replace it entirely. The surrounds are relatively new but look pretty dodgy and I am anticipating doing them too, as well as a complete recap.

My question is around other 'improvements' that I could consider doing, that I could also practice on my AR TSW-610's with. A lot of the people on the Polk forum talk about using Larry's rings or, in their absence, Hurricane nuts in order to achieve a better seal between the driver and the baffle; and they also apply additional sealant to the inside of the enclosure joints to ensure the cabinet is airtight. They also apply Dynamat to the driver baskets, presumable to reduce vibrations, and deadening material, eg Blackhole5, to the cabinet behind the bass driver.

As AR drivers are acoustic suspension, I believe they also rely on a tight seal. Does this mean they would also benefit from putting in Hurricane nuts and sealant? What about the Dynamat and deadening material? Would this help the sound from drivers in non-Polk speakers?

Also, I saw someone who had restored a pair of AR9's and they removed the acoustic mat from the fronts and also the metal logo panel, in order to render it 'nude'. I love that look and think that if I am applying entirely new veneer, I'd love to make mine nude too. What would be the effect to the sound of removing the acoustic mat? Some people think the mat makes a difference, some don't.

In addition to these potential improvements, are there any other structural or mechanical improvements that could be made to the AR9's while I'm busy restoring them?

Thanks in advance for your advice.

David

 

[Aadams]

You are asking for advice on modifications to AR speakers.  You won't get much help in this forum.  Your post is more properly located in the Mods and Tweaks section.

The "nude" AR9s to which you refer were modified in appearance only IIRC.  Aside from replacing the rupture prone Callins caps, it would be difficult to electronically modify an AR9 and actually make an audible improvement.

[ar_pro]

The factory-standard foam gaskets for the drivers are very good at their job; just use fresh gaskets when you change out drivers.

I can't imagine any need to further seal the interior cabinet joints - the AR-9 box is very tight. Ditto for replacing the standard t-nuts with another sort of fastener - you can really torque the t-nuts down for a perfect seal. But be careful when re-installing the woofers, that you don't initially lean into the screwdriver when replacing the screws, since this could cause the t-nut to come loose and fall into the cabinet. The less wear & tear to the particle board around the mounting holes, the better.

Since you're doing a complete restoration and re-veneer, you can simply disassemble the entire system, and work on the components individually. Case in point: the AR-9 level control switches are prone to intermittent noise, and should be thoroughly cleaned. They're attached to a circuit board, which is held in place by nuts that are under the three switch cups. The "metal" decorative sticker is actually vinyl with an adhesive backing - there is no practical way to remove the sticker without destroying it. Same for the Acoustic Blanket - the glue is tenacious, and it will be very difficult to remove the Blanket in a single, undamaged piece.

As far as "naked" goes, I much prefer the appearance of the speaker without the Blanket and vinyl sticker. Sound-wise, the effect is that the system seems less-directional when listening close-up - say, 6-8 feet away - but at greater listening distances, I've never been able to hear any difference between a speaker with the Blanket, and one without.

On modifications, adding spiked feet can be beneficial, as is replacing the barely-adequate binding posts with more robust versions. 

There are many threads on updating the AR-9 crossover, so dig deeply into them, and it would be useful to study the AR-9 blueprints, just so you can see what you're going up against.

Good luck with your restoration!

 

[VinylChef]

11 hours ago, Aadams said:

You are asking for advice on modifications to AR speakers.  You won't get much help in this forum.  Your post is more properly located in the Mods and Tweaks section.

The "nude" AR9s to which you refer were modified in appearance only IIRC.  Aside from replacing the rupture prone Callins caps, it would be difficult to electronically modify an AR9 and actually make an audible improvement.

Thanks very much for your reply. Appreciate it.

And I'll be more mindful about where I post in the future!

[VinylChef]

Thanks ar_pro for your reply. I realise now that the nude pics I was so impressed by were from your old post! Beautiful work, btw... I hope to emulate it!

5 hours ago, ar_pro said:

The factory-standard foam gaskets for the drivers are very good at their job; just use fresh gaskets when you change out drivers.

 

Is this an example of the fresh gaskets you are referring to:
https://www.ebay.com/itm/ACOUSTIC-RESEARCH-WOOFER-FOAM-GASKET-TAPE-/193214639910

5 hours ago, ar_pro said:

Since you're doing a complete restoration and re-veneer, you can simply disassemble the entire system, and work on the components individually. Case in point: the AR-9 level control switches are prone to intermittent noise, and should be thoroughly cleaned. They're attached to a circuit board, which is held in place by nuts that are under the three switch cups.

Great tip about the switches and the fact that I can deal with every single component while I am restoring the cabinets in their entirety.

5 hours ago, ar_pro said:

The "metal" decorative sticker is actually vinyl with an adhesive backing - there is no practical way to remove the sticker without destroying it. Same for the Acoustic Blanket - the glue is tenacious, and it will be very difficult to remove the Blanket in a single, undamaged piece.

I guess it is no way back once I've decided to do this! (The veneer is so bad that I feel I've no choice but to remove it all and replace it. As the vinyl sticker and blankets sit over the front baffle, I guess don't really have a choice but to remove them in order to replace the veneer under them.)

Thanks for the rest of your tips. I'll read everything I can possibly find about the AR9 crossover etc before I embark on this adventure!
 

[ar_pro]

16 hours ago, VinylChef said:

Thanks ar_pro for your reply. I realise now that the nude pics I was so impressed by were from your old post! Beautiful work, btw... I hope to emulate it!

Is this an example of the fresh gaskets you are referring to:
https://www.ebay.com/itm/ACOUSTIC-RESEARCH-WOOFER-FOAM-GASKET-TAPE-/193214639910

Great tip about the switches and the fact that I can deal with every single component while I am restoring the cabinets in their entirety.

I guess it is no way back once I've decided to do this! (The veneer is so bad that I feel I've no choice but to remove it all and replace it. As the vinyl sticker and blankets sit over the front baffle, I guess don't really have a choice but to remove them in order to replace the veneer under them.)

Thanks for the rest of your tips. I'll read everything I can possibly find about the AR9 crossover etc before I embark on this adventure!
 

Oh, you're welcome. The AR-9 is a great speaker, and certainly worthy of a careful restoration and update. 

The gasket tape in your link appears similar to the product that Parts Express carries, and that many here have successfully used on their various projects.

Getting the Blanket off intact is pure hell, and I've only managed it one time. Removing the Blanket and the vinyl sticker is difficult enough without damaging the veneer beneath, but that won't be an issue for your project. Here's a couple of old photos of the before & after on one rebuild - it took both stripping & sanding to remove the glue and felt residue left by the sticker & Blanket.

Please be encouraged to take lots of photos of your project - everyone here enjoys seeing what other guys are up to.

 

[Michel Pe]

Hi Don, 

I just restored a pair of AR9... here’s my take on a few things you might want to consider. 

First, it might not be necessary to re-veneer them... I thought I would have to do so myself but after careful sanding, I managed to get the veneer back to a clean enough surface to re-finish; and mine were pretty bad! 

Secondly, before you recap anything, try them out once re-foamed. I was concerned with the condition of the crossovers and talked about it with my speaker technician; basically, he said that if the cans haven’t leaked or haven’t swollen up ... they should still be good! Luckily, I have an honest tech and I can’t stress enough the importance of having work done on your drivers by anyone else but a specialist! 

Thirdly, I replaced both tweeters... found replacements at simplyspeakers.com ... they had the best price! 

forthly, the AR badge on the front grill of my speakers were a screw-on type ... check before you try to pry them off; you might just have the same and just need to unscrew them! 

Lastly, like someone mentioned above, these are well sealed enclosures ... there’s no need to re-enforce in any way. Though you might want to change all gaskets; check they’re condition first... they might be ok! 

Good luck with your project, AR9’s are amazing speakers! Well worth restoring methinks! 

cheers

[Michel Pe]

[Stimpy]

I believe I see Black/Red Callins capacitors on your crossovers.  Not good.  They tend to drift out of spec, and leak as well.  You should consider replacing them.  Otherwise, Nice Job...!

[lance G]

Tung oil is lovely stuff for finishing wood, I have used it on many things with great results.

However I believe the original treatment for the AR9 was boiled linseed oil, therefore that's what I used when I treated mine.

Fully agree with Stimpy regarding the Callins capacitors and their likely need for replacement.

They are considered by many as very good speakers in their original form.

Good luck with the restoration. Well worth doing properly.

[DavidR]

1 hour ago, Stimpy said:

I believe I see Black/Red Callins capacitors on your crossovers.  Not good.  They tend to drift out of spec, and leak as well.  You should consider replacing them.  Otherwise, Nice Job...!

Even the ones that still measure in spec should be changed. A lot of the caps in my AR90s measured in spec. Some were very close and none were leaking (unlike in my 1st pair of 9s) BUT they were doing a better job of acting like a resistor than a capacitor. I thought my tweeters had dried ferrofluid but with new caps they sound wonderful again.

[DavidR]

I restored a pair of TSW610 for my son. Be careful removing the PCB board that holds the caps and resistors for this speaker. You need to unsolder both binding posts AND sometimes they also added glue to hold the PCB in place. I will never understand why they mounted the caps on the side that faces the rear speaker wall.

[johnfalc]

Best leave the boards holding the crossover components in place.  There's plenty of room to do the work without their removal.

Also - as others have said - replace at least the caps on the board handling the non-woofer speakers.  Look here by searching on AR-9 for a clear demonstration by several of us as to why - many of these caps are out of value by well over 100% - in my most recent AR-9 repair two caps (the 6uF ones) were out by 416% and 1,180% - do you really want capacitors in your crossover that are, for example, >75uF instead of their nominal 6uF?

[VinylChef]

On 2/9/2021 at 11:16 PM, Michel Pe said:

I just restored a pair of AR9... here’s my take on a few things you might want to consider. 

First, it might not be necessary to re-veneer them... I thought I would have to do so myself but after careful sanding, I managed to get the veneer back to a clean enough surface to re-finish; and mine were pretty bad! 

Thanks for the tip Michel. Unfortunately the previous owner had put all manner of dents in the veneer, even with a large chunk taken out of one of the sides. He had started to bog up all these dents and was in the process of painting over them with dark brown paint to try and convince me they were in great condition when I turned up to buy them!

I think I'll end up sanding down the veneer at least so it will accept new veneer over it.

Thanks for the photos of your AR9's. The cabinets do look just lovely!

[VinylChef]

On 2/10/2021 at 6:07 AM, DavidR said:

I restored a pair of TSW610 for my son. Be careful removing the PCB board that holds the caps and resistors for this speaker. You need to unsolder both binding posts AND sometimes they also added glue to hold the PCB in place. I will never understand why they mounted the caps on the side that faces the rear speaker wall.

Coincidentally, I only just restored a pair of TSW-610's! As in, last week! I put in new capacitors and binding posts and new surrounds. And they are just lovely now!!!

I agree that it is strange that the crossover board is inverted. I left some plywood on the inductors along with a fair amount of glue when I pried them out...