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AR-94Si "Improved"


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A friend gave me a pair of AR-94Si speakers. The woofer foams were rotted away and the "sock" speaker grilles looked a bit shabby.

These are from the "9" series but not TOTL. I have a pair of their bigger brothers, the AR-91, which are wonderful speakers--direct descendants of the 3a.

A search found surprisingly little about these. And it gets confusing because there were also the AR-94, AR-94R, AR-94S and the AR-94Sx. Apparently all a bit different. The 94 seemed to be the most expensive of the lot and it looked different with a sloped front. http://www.tnt-audio.com/clinica/ar94rebuild_e.html

Back in '06 Roy wrote that the 94-Sx is very similar to the Si. He wrote " these speakers can produce a great deal of very satisfying bass. The midrange balance is so-so (probably why AR kept messing with the crossover ;) ) and the highs are fine...just my two cents. They have worked well for me for video sound, the tall cabinets being a plus for that application. They are worth $100 to bring them back to life if the cloth and tops are in good shape. I would not break the bank restoring this model however." http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=1530

So my goal was to restore them without "breaking the bank".

In '08 CSP member kkc posted a pdf file on restoring the 94Si. It was informative but some of his upgrades such as replacing the coils with air core, the caps with Clarity Caps and replacing the internal wiring with "big chunky multi-stranded OFC copper" did not seem cost effective in terms of getting the most bang for the buck. I did note that he said the tweeters were too bright so he replaced them with Dayton DC-28F-8 units. Food for thought.

I had a lot of communication with Roy. He was not a fan of the 94Sx but he suggested a couple of mods: Reduce the 5uF tweeter cap to 4uF, Increase the 40uF cap to 70 or more (I noticed the 94S had a 100uF cap), put the woofer on the bottom. Unfortunately this was later in the string of emails and I had already rebuilt the xo and didn't feel like tearing them apart. Maybe later. The "woofer" and "mid" are identical drivers and the mid is on the bottom. To swap them I'll have to add extensions on the green and white wires.

So here's a summary of what I did:

  1. Ditched the socks. This allowed the next 3 changes, which I believe are real improvements.
  2. Moved the speaker terminals from the bottom of the speaker to the back.
  3. Replaced the cheap spring terminals with 5-way binding posts.
  4. Added an L-pad in the tweeter circuit to tame any perceived brightness.
  5. Refoamed the 4 woofers (or 2 woofers & 2 mids).
  6. Added a 1"x1" oak brace front-to-back for increased rigidity.
  7. Replaced the NPEs with film caps. The 5uF was replaced with a 4.7 Carli and 0.22 WIMA (I could go in and snip the leads on the 0.22's but two Madisound 2uF caps would have been better). The 40uF was replaced with four Madisound 10uF surplus film caps but then following Roy's advice I added a 33uF NPE from my parts box, so those are now 73uF.
  8. Removed the solid walnut tops and sanded them down to bare wood. These were not oiled. They seemed to have a polyurethane finish so I used Minwax "Wipe-On Poly" gloss finish.
  9. The thick felt diffraction "blocks" around the tweeters were replaced with Madisound felt diffraction rings.
  10. The cabinets were sprayed with PlastiCoat Truck Bed Liner. It took one rattle can per speaker so it probably would have been more practical to use the roll-on version.
  11. Built new grille frames of 1/2" x 3/4" pine "parting strip". These will probably be covered with black stretchy grille cloth but I need to notch out the backs of the frames first to clear the woofers' rims.

That's it. Photos of the finished speakers to follow.
Oh yeah. How do they sound? Pretty awesome with Rock music. I turned the tweets down to about 3/4. Have not yet listened with classical and jazz but I don't think mid-range is this speaker's strong suit. Nevertheless, vocals by Roy Orbison and Mark Knopfler sounded good.





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This is a rather interesting modification and indeed, the AR-94 variations do seem to have quite a range of components and specifications. Not particularly pertinent to JKent's 94Si's, but the image below, for AR-94's and AR-94Sx's, suggest substantial differences in efficiency, nominal impedance and crossover frequencies.

The comment (and photo) that caught my attention was that the two 8" drivers in these speakers were identical, and they seem to have an unfamiliar (to me) cone material. I may be mistaken about this, but I believe the original AR-94 used p/n 200001-1 (same as AR-17, 18 and others) for the woof and p/n 200027 (same as LMR in AR-9 and 90) for the mid. In other words, high-quality drivers found in some of AR's top products.

I was surprised to see mentioned here (re: kkc's post) and in other online discussions that several listeners find these tweeters undesirable - - - for my ears, I happen to really like virtually all of the variations of AR's 1-1/4" tweeter, but if some listeners find it too bright, I guess it can't hurt to add the tone control in the form of a new L-pad (that didn't show in the pics, did it?). I did notice that in JKent's pair that the tweeter leads were the s-shape variety, whereas the original AR-94 literature shows tweeters with straight lead wires, perhaps confirming that all three drivers had been changed by the time of the AR-94Si model.

post-112624-0-81682600-1400862079_thumb. post-112624-0-05601700-1400863358_thumb.

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All four 8" drivers in these 94si's are marked:


Roy said they are Tonegen and although they seem lightweight compared to "classic" AR 8" drivers he assures me they are good quality.

The L-pads are not shown. When I have some better photos I'll post a pic of the back.

According to Roy the Si and Sx seem to be essentially the same except for the solid walnut cap on the Si.


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Nice work as always, JKent, particularly those new grille frames. I think I finally figured out what I was looking at in pic 3 of your original post - - - looks to me like the speaker cabinet, upside down, with new holes in rear face for binding posts (larger hole) and L-pad (smaller hole, and near tweeter). Also, it appears you've filled in the void on the bottom where the original speaker wire terminals were located.

Methinks Roy is most probably spot-on, as usual, since this schematic for the AR-94sx looks exactly like your original crossover with the identical 8" drivers. Nice retrofit, looking forward to finished pics.


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I think I finally figured out what I was looking at in pic 3 of your original post - - - looks to me like the speaker cabinet, upside down, with new holes in rear face for binding posts (larger hole) and L-pad (smaller hole, and near tweeter). Also, it appears you've filled in the void on the bottom where the original speaker wire terminals were located.

Exactly right. Sorry about the ambiguous photo. And yes--that is what the xo looked like before I increased the 40uF to 73uF and added the L-pad, I'll get better pics up when I can. Thanks for the kind words.


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OK. Here are photos of the completed project. btw--Huw Powell provides a how-to on re-covering the grilles here: http://www.humanspeakers.com/howto/grill-cloth.htm

In the photos you can see the textured finish, new grilles with stretchy black cloth, original walnut top caps, sanded and refinished with wipe-on poly. On the back are the tweeter level control and new 5-way binding posts. I salvaged the original serial number stickers and attached them.

Still not sure about whether to put the woofers on the bottom or reduce the 4.92uF cap. They sound pretty good as-is. Strong bass, so maybe I don't want to move it closer to the floor. I like the tweeter adjustment. It's at about 1/2 in the photo but 3/4 sounds good to me.

I have tried jazz and classical and found these speakers to be quite satisfying. They don't have the soft, laid-back sound of the 3a's but I can't find any fault with them. Maybe a side-by-side comparison with the 91s is in order.




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Nice job Kent, they look great!

I like how you moved the speaker connectors from the bottom to the back.

You did a hell of a job on the grills too.

You've got a nice set of speakers now......sit back and enjoy them.


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Ditto on the "nice job" comment, and I rather like the revisions you made here (terminal relocation, addition of tweet control). As usual, your projects are very well-documented, while clearly explaining your observations, biases (who, me? -_- ), and objectives. Further, your historical research, explanation of detail, and sense of humor always contribute to an interesting read.

Speaking of biases, I can openly admit that I've always been very partial to the walnut-linen look of the early speakers, and to that end, my modest collection is intended to become part of a desired visual furniture aesthetic. No doubt at all that the original 9-series (9, 90, 91, 92, 93, and 94) are really terrific speakers, but for my tastes, the vertical orientation and black cloth have always been a bit too visually aggressive. Those sheer fabric socks?..... definitely not AR's shining design moment - - - not a bad idea to ditch them from the start.

Enough about me, so back to the speakers. It is great to hear that you have no audio criticism, and once again, the new rear tweet control and wire terminals might just be an obvious improvement over the original design. Two final thoughts or observations: (1) how does the addition of the non-original L-pad affect the ultimate performance of the tweeter (re: added circuit resistance); and (2) this version of "94" is sort of interesting since it utilizes the exact same driver for "woofer" and "upper woofer" (or midrange), and all performance differences between the two 8" drivers are achieved thru crossover manipulations.

Yet another interesting project.

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Thanks guys.

ra.ra: I agree on the early AR "look". In fact, my other current project--definitely NOT classic New England--is the "Rompicollo" ported design by Johnny Richards, using some no-longer-available PE buyout drivers and nice looking walnut cabinets salvaged from some unimpressive SA finds. I'll be adding linen grilles to those and they'll look sort of like AR-4x's. "Naked" photos attached to post #28. here: http://techtalk.parts-express.com/showthread.php?225010-Rompicollo-8-quot-2-way/page2 "Clothed" will follow.

Now an admission: I seem to think nearly every speaker I build or restore sounds "good" so take my recommendations with a grain of salt. The Rompicollos were a bit boomy without any cabinet damping but with the addition of some foam rubber they sound very nice. These 94Si's also sound good. I trust Roy when he says the bass and treble are this speaker's strengths while the midrange balance is "so-so" but I've been listening to a variety of music including some male and female vocals, and can't find any fault with these. I do turn the tweets down a bit but that may be because I'm used to the AR-3a sound. Maybe the combination of increasing the value of the woofer cap from 40uF to 73uF along with the tweeter attenuation did the trick. Wish I could give a more definitive description of the strengths and weaknesses. :unsure:


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Have never even heard of a Rompicollo, but I think you're right - - - with some off-white grilles and from a distance, at first glance those speakers might pass for decent impostors of the early AR's.

Not unlike yourself, I, too, have stated on these pages my own inability to describe sound perception in meaningful words. For my own projects, my personal limitations (in equipment, testing, and general audio know-how) prevent me from taking measurements or producing graphs to offer definitive performance results, so I just use my aging ears for evaluation.

Regarding your comments about the midrange performance, this evaluation does not surprise me when the speaker in question uses the exact same driver to cover two different ranges of frequency response. As corners were cut (engineering, production costs) in the later incarnations of the AR-94, it appears that performance suffered accordingly.

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