genek

The long face that's in shadow in photo #2 looks stripey enough to be korina, but the tops don't. Could be that the photos are washed out or the tops have been sun bleached. The face frames just look like generic "blonde." Do we know if the korina cabinets had solid wood korina face frames, or did they use birch the same way they did for the pine cabs?

Consider doing what Micro Acoustics did when they designed their add-on tweeter. Multiple capacitors and a switch to enable the selection of different crossover frequencies. The MS1 could be set to cross at 2500 or 5000 Hz. For this setup, I would suggest switching between 700 and 1400 Hz (which was the crossover frequency of the early 2ax with cloth surround woofer).

Here are the response curves for the 2 and the 1ms (1ms on top). The 2 has a flat response up to about 1200Hz, after which response becomes more variable for the upper 800Hz of its operating range. The 1ms is relatively flat from about 700Hz up, and is rather jagged below that. I'd say your best crossover point would be somewhere in the 800-1200Hz range. The 4" woofer in the 1ms and the 4" mid in the 48 series are not the same P/N. The tweeters in the two models also have different P/Ns.

The 10" woofer in the 2 is a more capable driver than the 4" woofer in the 1ms. If reducing driver stress is your goal, you'd be better off raising the high-pass filter frequency to take the load in the under-2000Hz range off the 1ms.

Just take the values from the schematics for the 3a. The 3t and 3st were designed to duplicate the crossovers from the 3.

If the 1ms is doing a good job with mids and highs, you'd be better off removing the jumpers to disconnect the original mids/tweeters and just use the 2s as woofers. Positioning the speakers vertically is producing a narrow vertical mid-frequency beam along the front axis of the speaker boxes because the cross-fired drivers were designed to be placed horizontally. The 1ms is a 8 ohm speaker with a bottom end somewhere around 85-90 Hz. Response becomes a bit ragged below 200 Hz. The 2 and 2a are 8 ohm speakers whose woofers cross to their upper drivers at 2000Hz. If you insert a 100mfd capacitor on the + lead to the 1ms, that will provide a high-pass filter that cuts off frequencies below 200Hz. If you're happy with the performance of the 10" woofer in the 2s, then just removing the jumper will roll them off at the original 2000Hz and no additional coil should be needed.

The square openings are common. There's a box behind it that keeps the cabinet sealed for the woofer (the 755 is not an acoustic suspension driver).

History probably has a lot to do with the AR-2ax, which started out as a 2-way speaker with a pair of cross-fired cone tweeters. In its final form, the 2ax is really still a 2-way speaker with a supertweeter added on, because other than the addition of the HF driver, its crossover design didn't really evolve much.

You should put a bit of sealant on the hole in the tweeter flange that the wire is passing through.

Another option you might consider is padding lacquer,, which as the same suggests is applied with pads in much the same way shellac is used for French polish. I've used a Behlen product called Qualasole, which works well, though not on anything as large as an AR-3:

I've not had good experiences with rattle can lacquer. The spray droplets are too large to lay down really thin coats, which is what you need to build up a mirror gloss finish. Though I suppose if you're determined you could rub it out the same as brush on lacquer.

Mahogany only came lacquered. Applying lacquer yourself without the right equipment (spray guns and a booth) and getting a good finish is both difficult and annoying, not to mention potentially dangerous. I was suggesting ironing simply as a means to reduce the amount of sanding you'll need to level out the surface. There's no chance you'd be able to only iron. Depending on how the sanding goes, it might be best to apply a sanding sealer before you do the finish coats.

You'll probably end up sanding and putting on a new finish, but if you do the steam iron trick first, it may reduce the amount of sanding needed to level the scratches. You can "restore" the patina of aged mahogany by "aging" the sanded wood with a potassium dichromate solution prior to refinishing. https://www.sawdustzone.org/articles/tutorials-how-to/824947-potassium-dichromate-chemically-coloring-wood

I suspect that determining how much it would cost to achieve that AR sound using modern components is one of the major points of interest in this topic.

How would using AR or Allison hardware meet the criteria of using "modern components?"

The thing you have to watch out for when finishing with polyurethane is that unlike traditional finishes like shellac, varnish or lacquer where each new coat will chemically merge into the coats before them, bonding multiple coats into one, poly will not. The solvents in which poly solids are suspended don't react with cured poly. You can apply multiple coats, but each new one lay up on top, so before you put on another coat it's much more important to make sure the previous one is as free of imperfections as possible. If I'm not spraying I prefer to wipe or pad on, because no matter how careful I am with a brush I always seem to end up with a stray bristle embedded in the finish. If you apply multiple coats of any finish, regardless of what surface sheen you want from the final coat, all the ones before it should be gloss. The flatting additives used to make satin or matte finishes tend to be just a tad bit obscuring, and applying a lot of coats that contain them can result in a cloudy finish. My personal preference is to use only gloss and after the finish has fully cured to take down the shine with abrasive pads or compounds until I get what I want. Poly wood finishes are pretty similar to automotive clearcoat, so you can definitely accomplish good things with car products.

Since I already have all the vintage AR gear I have room for here, I'd just put on some music, relax and keep my eye out for new technical bulletins from Dolby Laboratories.

I envision the ultimate answer as an array of sources whose combined frequency response and reverberant field are digitally modeled and controlled. Component frequency response would become irrelevant because of equalization, and component dispersion would become irrelevant because the field is generated by modulating the output of each source. Think audio holodeck. The question would be, would you still want to recreate vintage AR sound, or knowing the original of the vintage design was to simulate the sound of a live concert, would your target be the original live performers in, say, the Boston Symphony Hall?

Were there any 4-way AR speakers other than the ones with side-firing woofers? I'm wondering if the reason they were 4-way was just that they wanted lower midrange coming from the front instead of the sides.

With regard to the comments about "vocal heavy popular music," the jazz and classical music that AR's classic era ads leaned toward both had plenty of vocals. And if I'm choosing a vocal to use as a listening test source, I'll take Sarah Vaughn or Maria Callas over David Lee Roth or Axl Rose any day.

They're not mutually exclusive, except in cases where some manufacturer is still offering "non modern" products for sale.

The original question specified "devices in today's audio market."

Probably because it just didn't show up when I googled "3 way acoustic suspension speaker." Would it be enough just to use the subwoofer's low-pass, or would you want an external crossover that rolls off the lows on the satellites as well?

The original question assumed that someone wanted "acoustic suspension sound" and was tired of trying to keep old speakers alive. So the "modern components" being referred to are whole speakers that can be bought today and somehow combined and/or manipulated into producing AR-like sound (either Classic or post-Classic, since no particular AR era was specified). We already have plenty of other discussions about suitable replacement drivers, and there's already an old discussion somewhere about how a new speaker could be built from scratch with new parts that could be revived if anyone is interested, but that would be at least as much work as trying to keep an old speaker alive. So let's not confuse this one.

No. I went looking for a 3-way acoustic suspension speaker one could add a 12" subwoofer to, and that Yamaha bookshelf box seems to be the only one there is.