AR-9 Refurbishment

[RoyC]

Ok, so after a little bit more thought, honestly, removing the switches is not a downgrade. If you were to leave the switches at 0dB at all times the switch should not really add any more resistance, unless it's corroded (which all old switches are). The resistors are only in the circuit when the switches are selected at either -3 or -6dB. So, if you were to disconnect the wiring to the switches and utilize said wire to make the proper connections to the binding posts, little to none of the originally intended resistance would be lost (presuming the 0dB switch posistion).

Granted, in this case eliminating the switch is not a "downgrade" in the 0db position. Eliminating the other two options, however, is certainly not an improvement relative to the original design. (I personally have not preferred any AR speaker at the "0db" or maximum switch/level control setting in most circumstances.)

There are reasons AR provided response contouring options....one of the most important being adaptability to various listening spaces. Elminating the switch will get you going, but ignoring its contribution is a mistake, imo. There are significant crossover changes produced by the switch's series resistors shown in the schematic. The switch is not simply attenuating the drivers associated with it. It is changing the character of the overall response of the speaker.

Roy

[Robert_S]

A previous topic referenced an interview (in Italian) with Tim Holl, by Renato Giussani, where the switches in question were mentioned:

http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=5768

The following excerpt in particular is relevant:

"Q. What is the function of the “mid-low, mid-high and high” level controls on the speaker?

A: First, I must say that our Marketing Department has told us that it is very difficult to sell speakers without controls, so we mounted controls in accordance with the Sales Office’s request. But, in the case of the AR 9 and 90, these really help calibration in various listening environments. As a matter of fact, there are rooms furnished with reflective and absorbent furniture and the effect is a variation of the response in the medium or medium-to-high range; with the controls on the speaker it is possible to vary the characteristic of the response in a very complex way and obtain a good balance. However, I don’t think it’s possible to correct for a variation of the response of low frequencies using the controls because these work in an invariable way on an entire range. For example, the control of the low midrange works in the same way on the entire range from 200 to 1000 Hz while that which may be desired is an action like the control of the amplifier’s low frequencies, which is gradual; the speaker checks are carried out using resistances with increments of 3 dB.

It is a rather brutal adjustment technique but we have seen that many people prefer to listen using midrange and tweeter controls lowered by three dB, especially in environments that are not very absorbent. Personally, I use the AR-9s in the Flat position and I obtain the variations I want using the tone controls but, normally, we don’t have to correct the response of our listening room at AR, in which everything is set to flat.

Q: Do you think that controls of the speakers can also help adjust the response depending on the type of music or recording technique used?

A: Yes and no; if you’re referring to the pure frequency response, probably not, but if you’re referring to the sound that over a long period of time the person who bought the speaker may prefer then this is the best way to obtain it."

Source (courtesy of Steve F, translation by his daughter): An Interview_With_Tim_Holl.pdf

Robert_S

P.S. Ken Kantor's controversial view regarding October hyena audibility is perhaps best put on pause for the duration of this discussion.

[Mach3]

Jeez Louise - the mere mention of wire gets everybody's panties in a wad. Foaming and roaring as the "wire is wire" types trot out their old, tired defense of whatever cheap wire they endorse.

For the record wire, at least some wire, can make a significant difference in the sound quality of a system. I am not endorsing the lunatic fringe wherein people pay thousands of dollars for 2 meters of wire. I am saying that wire is not all the same. I also believe that the wire used in the AR-9 is cheap, barely able to do the job and the fact that is was pre-tinned has no sonic significance at all - more about typical industrial usage, e.g. the pre-tinning makes it easier to solder, than anything else.

As for Russel and his "report"; a clear example of somebody trying desperately to find data to support his a priori conclusions. Unlike Russel I do know that wire has associated capacitance and inductance. And that these values do make a difference in sound quality. For anybody who thinks differently then I suggest that you go borrow a piece of basic Kimber wire (interconnect or speaker) and place it in your system - you will hear a difference, even if your rig is a pile of junk.

Concerning Russel's "superior qualifications" - hey this is science and science doesn't respect authority. No bishops or authority figures in this field (a reaction to medieval thought models). All science respects is data as reflected by measurable performance. So don't try running that rhetorical red-herring.

Or go look at the difference between CAT-3 and CAT-7 (Ethernet or 802.3 wire) - the twist is tighter and consequently higher speeds (larger bandwidth) can be accomodated. Therefore wire is not wire - there are characteristics to wire that contribute significantly to the sound of a stereo system. Cheap, thin, industrial junk wire, such as used in the original AR-9 is easily transcended.

BTW: All of my "flat wire" was twisted by myself prior to installation. I believe that doing so gives me greater noise immunity - and the inside of a speaker is a very EM noisy environment what with all those coils and speaker motors firing constantly (pulsing EM fields).

I will say no more regarding wire. Use it or don't use it it is of no concern to myself. I certainly know what I hear and until you try some higher grade wire then you have effectively nothing to contribute.

[ar_pro]

"All science respects is data as reflected by measurable performance"

You wish.

Science has been rife with controversy, fraud, and axe-grinding, and can be as susceptible to the influence of opinion, money, or politics as any other aspect of human life.

"Climate-Science", anyone?

50 years ago, most high-fidelity loudspeaker manufacturers employed very similar types of wiring in their products, and ironically - even after five decades' "accumulated knowledge" on the subject - there are any number of dissimilar types of wire that are in use in today's designs.

This tells me that a hard & fast rule does not exist, and that "Science" does not rule the day - at least as far as loudspeaker-manufacturing goes.

Anyway, you're certainly entitled to your opinion on the importance of changing-out the original wire on the AR-9 - you would not be the first person to have done this - and as long as you're pleased with the end result, who really cares?

[Gerry S]

Sometimes small gauge internal speaker wiring is actually desirable. By changing it to a larger value, the "original" desired frequency response can be changed as well. When I did my XO work at BA, I included the DCR values of the chokes as an integral part of the crossover. This means possible elimination of a required resistor or two. Substantial differences in wire gauge could affect crossover points, tonal balance, impedance values, etc.

As a tinkerer, it's very common to feel that ANY changes would automatically yeild positive results. Only after extended listening and/or objective data is generated can I be sure that any percieved changes are both "real" and for the better!

[RoyC]

Jeez Louise - the mere mention of wire gets everybody's panties in a wad. Foaming and roaring as the "wire is wire" types trot out their old, tired defense of whatever cheap wire they endorse.

Unlike Russel I do know that wire has associated capacitance and inductance.

Cheap, thin, industrial junk wire, such as used in the original AR-9 is easily transcended...

The only "panties in a wad" around here are yours, whenever you are challenged.

Obviously your calibrated ears, and vast experience easily trumps Russell. Hey, he must not know a thing about capacitance or inductance. What about the "function" of resistance? Do you really know anything about his background...or, for that matter, capacitance and inductance as it relates to AR-9 wiring? I think not...

http://www.roger-russell.com/

I'm OK with opinions, but misleading pronouncements cannot be ignored...

Roy

[Gerry S]

I'm kinda skeptical about this internal wire business for the AR9. For that matter, even external speaker wire. Has anyone tried blind AB'ing test to see if there are significant differences? If the differences show up consistently and repeatedly under controlled conditions, I'd be a convert.

I'm thinking that any differences that are heard with wires would be swamped by other factors that are several magnitudes greater in their ability to affect what the listener can hear.

On a similar vein, has anyone heared differences using bi-wiring vs using a single speaker wire? Again, the emphasis is on significant, repeatable differences, otherwise it is just added expense and unnecessary complexity.

[Pete B]

John Dunlavy's "Cable Nonesense" post - he is being generous in saying

that there are differences since the ones he talks about are at RF frequencies

not audio:

http://www.verber.com/mark/ce/cables.html

Of course DC resistance matters for long runs or very small wire where the

resistance becomes significant and alters the damping factor. And we have

to rule out cables that are deliberately manufactured with odd characteristics

to make them sound different under some conditions. Generally, all decent,

even low cost, cables sound the same.

[Gerry S]

Back to "spiked feet" (no, I'm NOT tring to be a "troublemaker"). Many decades ago, I attended a Boston Audio Society (BAS) meeting where someone was demonstrating HUGE subwoofer cabinets containing multiple 15" drivers (I think). I'll confess outright that I do not remember the details; please don't ask me for them!

I DO remember this..... what amazed me about the demo was that these subwoofer cabinets were LITERALLY "walking" across the floor when driven to high amplifier levels! VISUALLY impressive as this was, this is NOT good because this "motion" is energy being wasted. It would have been a much more effective demonstration AUDIBLY if they could have weighted or bolted the cabinets down to the floor. Of course, this would not have been practical; the host would not have appreciated finding mounting holes drilled in the floor the next morning. And, no one could find anything massive enough to put on top of the speaker cabinets to weigh them down. What bass I did hear was NOT "viceral" as one would think or hoped for. Kinda wimpy, actually!

So, why "spikes"? My theory: the cabinets when placed on carpeting won't "grab" or "anchor" itself to the floor or subfloor beneath it. At high playback levels, the cabinet may not be visually moving in an OBVIOUS way. But they ARE being excited enough to "move" or "rock" imperceptually!

I owned AR 10 Pi's many decades ago. Placed on 12-14" wood stands (to bring the tweeters to ear level) and resting on a carpeted cement slab floor, I noticed my speaker location changing a few inches; thought that someone moved them when vacuming the carpet. When I asked, not so. So I performend an experiment. Using rock music containing heavy bass, both cabinets moved several inches from their original resting position after several hours of use!

For the AR9, I believe cabinet design and construction is as "rigid" and as "inert" as possible WITHIN REASON. Any "heavier" or "deader" cabinet material (like concrete or lead) and cost would go WAY up, not to mention that it would be next to impossible to transport.

At "reaonable" playback levels, the weight of the cabinet is heavy enough to prevent obvious bass loss/interference when placed on a carpet. At high levels, a different story. "Spikes" would/should penetrate the carpeting and "grab" whatever lies beneith. Energy once used to "move" the cabinets (however slight) would be used to move the woofers. Ergo, more/cleaner bass.

So, that's my theory. Think of shoes (or hiking boots) with "spikes" or "lugs" for traction/grip on slippery surfaces. Without "spikes", smooth shoes will "skate" across the surface (just like my AR 10pi's on carpeting). With "spikes", weight is distributed to fewer points so it can grab or anchor more effectively.

My theory (inelegant as it sounds) makes sense to me. But it may be incorrect. Perhaps others can clarify or correct me.

[AL78]

Hi great job on those speakears.I have a question how do you restores the cabinets.I have a pair of ar 7x to restore the cabinets need some refreshing.they look like the one in the right in your picture.Did you scrap all the old varnish or just put some clean layer on?thank you

[SHOKDU]

I don't believe the original cabinets were varnished, they were oiled. I used Howards Dark Walnut restore-a-finish, 6 or so coats. Then I did 4 coats of Howards Feed-n-wax. A very simple restoration, but with superb results.

All, I promised better pictures, and here they are!

[AL78]

Thanks great job.Did you also build the shelf for the stereo?Great idea.Listen did you scratch or treat the cabinets in any way before using oil?merry xmas

[SHOKDU]

Yes, I built the rack myself. The hardest part was staining and poly coating. Very easy, and very sturdy. It cost me about $250 to build.

No, I did not scuff the wood. The Restore-A-Finish is like a wood treatment in itself. The Feed-N-Wax is a mixture of beeswax and orange oil, which are both fantastic for the wood.

[DON]

Hi to all. I've been away for several months because of health and a few hospital stays. This thread on the AR9s has encouraged me to at least go out and dust my 9s off. They're right where I put them in the garage after unloading. All the woofers and LMRs are out and the foam and glue residue have been removed and they are ready for refoaming. This and restoring the wood finish are well within my skill levels but the crossovers may be a real problem for me. I have very little electronic experience and soldering is difficult at times with the irons I've tried.

Anyway I'm looking forward to starting work on these jewels. I'll start with the surrounds and the wood first and hope that the results will encourage me to look at the X overs.

It's always a pleasure to read the comments on this forum.

SHOKDU

Your 9s turned out to be beautiful. I like your rack as well (any information on construction?). What is the material under your speakers?

[Joel]

Shokdu,

Have you tried placing your AR9's closer the back wall? According to the documentation, that is the way they were designed. It made a pretty big difference with mine. If you don't like it, you can always slide them back to where they are now.

-Joel

[SHOKDU]

Don, are you planning on cutting the dust covers back in order to shim the voice coil? A lot of people say that shimming is unnecessary, and while I agree, I disagree at the same time. A person really needs to examine the condition of the spider. If the spider is not level, if it's sagging, then the cap needs to be cut and the voice coil shimmed so that you can adjust the cone to the proper position so that the spider is not sagging while you do your refoam job. If the spider is flat and you feel you can get away with not cutting the dust cap, and not shimming, then obviously that's the easier path.

Soldering comes down to having the right tools. I use a Weller adjustable temp digitial solder station, a brass "ball" (instead of a wet sponge) for cleaning, and I use eutectic solder. There is no desoldering required with the AR9 crossover, but when desoldering is involved, a Hakko 808 is another must have. Another thing to have is a helping hand soldering stand. These can be life savers. With the right tools in hand, practice soldering wires together. Just remember you always want to heat the item being soldered, not the solder itself, and never move a solder joint until it's fully cooled.

When replacing capacitors do one at a time. Cut the leads as close to the capacitor as you can, then all you have to do is solder the leads from the new capacitor to the leads of the old capacitor that were left in the crossover. This makes for much easier work. The AR9 uses lugs in the pegboard not only as supports leads, but to conduct as well. What I found is that soldering direct to the lug can be a pain, and is unnecessary, that is why i suggest leaving enough of the existing leads to solder your new capacitor to. Test fit the capacitor, make sure you know where you want it set, then lay your hot glue down, set the capacitor in it, let it cool, then twist your wires, cut where appropriate, and solder. It's very easy really. I'm sure you can get it figured out.

Don, thank you much for the compliment. The rack was really very easy to build as well. I cut oak plywood to 2'x4', clamped 4 pieces together with wood clamps, and then I measured 2" from the outside edges on front/side and put an X, I did this for all 4 corners. From the center of the X i measured 22" and 2" in from the edge and put another X. I hole sawed through all 4 pieces of plywood from top to bottom, and when the pilot drill bit punctured through the bottom I stopped. Then I flipped the whole stack of boards over and cut the last bit of the holes out, do it this way so that the plywood does not split on you. When all the holes are cut out I sanded everything down with 80 grit, cleaned it very well, put 3 coats of stain on (sanding between coats), then 3 coats of poly (sanding between coats). I got my 3/4" hardware (nuts, washers, neoprene washers, acorn nuts, threaded rod) from Grainger, and assembled it all. Overall a very easy, but very time consuming project.

Joel, yes, I have had them closer back to the wall (as you can see in some of my earlier pictures in this thread). I've been experimenting with placement, so in a week from now the placement that you see in the pictures will most likely be different until I reach the point where they sound best.

[xpat]

SHOKDU,

Gorgeous system! Have a great New Year..

[djcheung]

Hi all,

I am a newbie here.

Just purchased a pair of AR9's and just considering changing the capacitors.

I am considering Clarity ESA caps.

Any opinions?

After replacing the caps, do I need to add resistors to compensate the difference in resistance between old and new?

Hence I am also looking at the resistor board.

Does anybody has the detailed procedure on how to take the attenuation/resistor board out - the one with the switches attached to?

Thank very much in advance.

David.

[xmas111]

David,

To remove the resistor board you have to remove the Black metal cup in front of each switch. Take an exacto knife or something similar and gently pry them off. There will a nut on each switch. Remove the nuts and you should be able to pull the board out from the inside.

Hope this helps.

PS. Putting the nuts back on the switches can be a real bitch! Hint: Use a very thin pair of needle nose pliers.....and have patience!

John

[ligs]

When I had AR9s my adjustments were mainly between 0 db and -3 db. Sometimes I really wish to have -1 db, -2db instead -3 db, -6db. For me I would leave the level control panels alone and just insert the new resistors between the crossover boards and the level controls. When you set the level controls to 0 db you essential bypass the entire level controls so the old AR resistors have no effect on the sound quality. My 5 cents.

BTW, replacing the old bi-polar capacitors with the newer film capacitors would result in louder spl from the mid and high drivers(due to the lower ESR). Unless you can voice the entire speaker with ears only it is not a easy job.

[djcheung]

Hi ligs,

I know when the switches are set to 0db, it bypasses the resistors board. I thought it may be useful if after changing the caps, I need to turn it down a bit. At least I will get the choice.

I have read somewhere that the drift in capacitance may damage the UMR and tweeter if it allows lower frequencies to come through.

Is that right?

Best regards,

David.

[ligs]

There is a thread about the values of AR 9 crossover, actual vs original. It came from KKC( Message #10.

http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=5317

I don't know about the drift in capacitance would necessarily damage the UMR and tweeter unless the values drift upwards substantially. In the case of the series capacitor to UMR it has drifted to 41 uF from the 24uf in the spec. Normally for electrical components specs are typically within +- 10%.

[Robert_S]

There is a thread about the values of AR 9 crossover, actual vs original. It actually came from KKC(Ken Cantor himself). Message #10.

To the best of my knowledge, Ken Kantor posts on here as "kkantor", see for example:

http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=7789&p=96834

Robert_S

[JKent]

Hi great job on those speakears.I have a question how do you restores the cabinets.I have a pair of ar 7x to restore the cabinets need some refreshing.they look like the one in the right in your picture.Did you scrap all the old varnish or just put some clean layer on?thank you

AR did not use varnish. Some of the early speakers were available in lacquered finishes (AR-1 through 3) but the 7 was either oiled walnut or wood-grain vinyl. Assuming you have the oiled walnut it depends how far gone the finish is. If it's pretty good you can just wipe down with mineral spirits and apply some lemon oil or Watco Danish Oil (Watco comes in shades such as Walnut and Dark Walnut). If you need a bit more sprucing up, several of us have had good success with Howard Restor-a-Finish. Wipe on/wipe off. You can also apply it with 0000 steel wool. After that, apply a coat of wax such as Howard Feed-n-Wax.

If they are more beat up, you can sand VERY VERY lightly. Gouges and broken corners can be repaired with epoxy (I'll elaborate if you decide to go that route), then refinish with Watco Danish Oil.

No varnish!

Kent

[ligs]

My wild guess got me this time. KKC is not kkantor