AR-9 First Restoration

[meta_noia_fot]

Hi Everyone.

I'm working on my first pair of AR-9s. My question today is about the wadding material. Attached is a picture of the material that is in there now. The larger cabinet has the same material. Is this the correct material for these cabinets? I've only ever worked on earlier models of ARs and none had material like this. I'm wondering if this is replacement material since the LMR woofers had been replaced at some point. Thanks for your help.

-George

[Aadams]

1 hour ago, meta_noia_fot said:

I'm wondering if this is replacement material

YES.  That is the correct stuffing for the AR9 series.  That cavity was stuffed very densely, specifically for the original 8" midrange driver.

[lARrybody]

Maybe somebody can explain to me why the upper three drivers have poly fill stuffing, but the lower dual woofer and crossover area is empty.  

 

[Aadams]

26 minutes ago, lARrybody said:

but the lower dual woofer and crossover area is empty.  

 

The woofer chamber has a hard packed mass of the same material in the upper half of the chamber.

[meta_noia_fot]

@AadamsThanks! Glad there's one less thing I need to worry about.

[DavidR]

The woofers and crossover area of the AR9 and AR90 is left empty on purpose (i.e. no poly-fill material). There is a thread on this site about it. The Tim Holl white paper on engineering the AR9 might also shed some light as to why. I believe it is an isobaric chamber.

[DavidR]

[meta_noia_fot]

Thanks @DavidR. Directly behind the woofers is empty in mine but there is dense material further up the cabinet. I believe my speakers are as they should be with regards to wadding material.

[DavidR]

Yes, above the xover boards is stuffing. IIRC, it is 4 rolled up poly wadding. I have an AR drawing showing it. I will look for it after dinner and post it.

[lARrybody]

This thread answered my question.

 

[DavidR]

Here is a drawing for the AR90. Not sure if the AR9 has the (4) rolled up stuffing. My 1st pair of 9s appears to be just pieces shoved in and not the rolls. I have not ventured inside my 2nd pair of 9s too deeply.

 

AR90-Drawing1of2.TIF

[meta_noia_fot]

Thanks for all the help previously, everyone. I'm in need of some more advice.

1. How should I attach new grill fabric? The previous owner had the fabric replaced at some point to a tan fabric (I hate it). The larger grills have the fabric attached just using glue. The smaller, side grills appear to be glued with a chrome frame stapled onto the grill (I assume this is the chrome piece I've seen people talk about omitting on other threads). If there is supposed to be chrome frames on the larger grills, they're missing. I've only replaced grill fabric on one set of speakers before (AR-6's) with sub-optimal results. And the only hi-fi store near me doesn't do grill fabric replacement unfortunately. If glue, any suggestions for a glue/fabric combo? Or should I just get a power stapler?

2. What about speaker spikes/feet? I noticed there are screw threads on the bottom of each speaker. Does anyone know a spike set that fits these threads? Or what the thread measurements are? I figure elevating the speakers may help keep the floating floor I'm on from vibrating during heavy bass passages.

3. Finally, any advice on placement in a small room? The centers of the vertical arrays are about 7 feet apart. Unfortunately there isn't much room between the LF woofers and the walls and a record shelf (see pic).

Thanks again for all your help.

[Aadams]

1 hour ago, meta_noia_fot said:

If there is supposed to be chrome frames on the larger grills,

No.

The original black fabric was stretched and stapled around the entire perimeter of the large grill.  Same with the woofer grills.  But glue would work as well if you are careful and patient.

Regarding placement.  You have plenty of room and enough options.   You don't need spikes but you could use adhesive felt pads to ease movement on the wooden floor.

Those baseboard heaters being so close would concern me but others may know better.

 

Above is a link to an AR 9 ref manual download.  Read the section on speaker placement.

Adams

 

 

[meta_noia_fot]

Thanks @Aadams. I think I'm experiencing the slight bass boost below 100hz the manual mentions. I'm going to experiment with EQ-ing the bass a small amount. 

1 hour ago, Aadams said:

Those baseboard heaters being so close would concern me but others may know better

 

I know in the winter I'm going to need to pull them at least a few inches away from the heaters. I'm also going to insulate those wires. The room, like the speakers, is a work in progress.

[blanddawg625]

On 7/31/2022 at 1:59 PM, lARrybody said:

Maybe somebody can explain to me why the upper three drivers have poly fill stuffing, but the lower dual woofer and crossover area is empty.  

 

It is because of the standing waves from the woofers which will resonate throughout the upper regions of the cabinet. The filling is there to stop this from happening.

[DavidR]

On 7/16/2023 at 12:11 PM, blanddawg625 said:

It is because of the standing waves from the woofers which will resonate throughout the upper regions of the cabinet. The filling is there to stop this from happening.

[frankmarsi]

So,

"Regarding placement.  You have plenty of room and enough options.   You don't need spikes but you could use adhesive felt pads to ease movement on the wooden floor."

To me, the pictured room is too small for those speakers, especially the woofers. Speakers do best when their stands or spikes, etc. are in direct contact with floors.

When I was inside my AR-9's the lower woofer-chamber was empty as I described in my 2014 post and certainly as DavidR has patiently explained here (3X). And as I recall, the 8 inch lower-midrange has its own separate mini-enclosure and stuffing.

I won't mention the amount of necessary wattage needed for the best results but,  I use 700 WPC RMS and they do eat it up quickly.

FM

 

 

 

 

 

 

 

 

 

598
 

[meta_noia_fot]

@frankmarsi It's an old house and I don't have larger rooms to work with. The room size certainly isn't optimal, but after listening to these speakers for nearly a year in this spot, it's hard to imagine being more pleased. That being said, I do plan on upgrading amps in the next year or so. I want something that can do at least 400W into 4 ohms. Currently I have an 80's Luxman that was advertised as delivering 170W into 4 ohms. A Nakamichi PA-7 would fit in well with my other equipment so that's what I'm considering.

I actually purchased a second pair of AR-9s over the winter at I think a great price. I plan on gifting my current 9's to my dad and recapping this second pair as my set. And all of my equipment is moving into a room slightly larger than this one later this year. If you think a pair of 9's is too big for that space ... I'm putting those 9's as a stereo set and a separate quad setup of AR-3a's into the new space.

Oh, and I could detect some vibrations between the wood pedestal built into the 9's and the wood floor. I ended up putting felt furniture pads on the base and that solved the problem.

Edited July 18 by meta_noia_fot