[Mitsuman]

Cast baskets are a more recent "boutique" phenomenon, in reality more to satisfy market expectations than for much real advantage, especially for bass drivers, I think. Witness Fostex drivers.

These were probably made by CTS of Paducah Kentucky, as were 90% of all drivers in the USA. With CTS, a manufacturer could specify almost any design parameter, even with relatively low-number production runs.

Uh, well all of my vintage Mitsu speakers from 1974-1979 all have cast baskets so I don't think it is a recent "boutique" phenomenon. 

[Æ]

Uh, well all of my vintage Mitsu speakers from 1974-1979 all have cast baskets so I don't think it is a recent "boutique" phenomenon. 

Yeah, I've seen some pretty old stuff that had cast frames. Can't remember the names, but bigger professional types of drivers used in studio or on stage. Cast frames for ruggedness.

[Russell Dawkins]

I still maintain it was market driven, and boutique. Cast looks so much cooler than stamped that it became associated with quality, and was thus presumed to sound better. I can see the advantage of not having a large reflective area behind the cone, but a lot of drivers did pretty well with that handicap.

..and 1974 is "more" recent than the AR-4X design, if not actually "recent". 

[Æ]

I still maintain it was market driven, and boutique. Cast looks so much cooler than stamped that it became associated with quality, and was thus presumed to sound better. I can see the advantage of not having a large reflective area behind the cone, but a lot of drivers did pretty well with that handicap.

..and 1974 is "more" recent than the AR-4X design, if not actually "recent". 

Well, just like one can conduct a "knuckle" test on an enclosure, one can also "flick" a stamped or cast woofer frame and easily hear the difference. Stamped frames kind of have a tinging, clinking sound to them. Whenever I use woofer with a stamped basket, I'll finger flick it and if it rings, I'll apply some of that peel and stick damping sheet material to the basket.

[Mitsuman]

I still maintain it was market driven, and boutique. Cast looks so much cooler than stamped that it became associated with quality, and was thus presumed to sound better. I can see the advantage of not having a large reflective area behind the cone, but a lot of drivers did pretty well with that handicap.

..and 1974 is "more" recent than the AR-4X design, if not actually "recent". 

All I know is that Diatone (Mitsubishi here) has used cast woofer baskets since prior to any of their speakers I own. I really think "boutique" and market driven were not as big of an influence in Japan during the 60's and 70's like we think of those terms now.

Sorry for the OT Wayner, I applaud your restoration efforts.

[Wayner]

Yeah, I've seen some pretty old stuff that had cast frames. Can't remember the names, but bigger professional types of drivers used in studio or on stage. Cast frames for ruggedness.

That would be JBL or Altec Lansing.....

W

[Wayner]

Cast baskets or better yet, die-cast baskets or the use of them is probably determined by expect quantities to produce, as the tooling for one size could be quiet high, like $50,000 or more. So you would need lots of units to amortize the cost of the driver. I'm pretty sure when the AR-4x was designed (1965 +/-) cost was a huge consideration, as it was the lowest priced speaker in the AR line, selling for $51 dollars in unfinished pine, $57 dollars for oiled walnut. How do I know this? I have a 1969 catalog from Allied Radio (from Chicago), and these are listed in the there.

The thing that always impressed me with AR is that they could make some damn fine speakers and not use way expensive drivers. The frames for the rest of the series, I'm betting is made out of stamped steel baskets as well. They are not pretty, but they are functional. At one time, AR had a huge, huge share of the American speaker market, I thought I read once, something like 80%, at least in certain regions. These boys were makin' some sawdust!

Too bad they chose the awful sponge surround for the rest of their line-up. I'd love to have a pair of AR-3a's, but I'm not interested in the reconing costs, let alone the rest of the rehab.

So far I have over 20 hours in these, and I'm not done, tho close to it. I have also spent about $50 dollars on supplies for the project.

I would not recommend refurbishing to a newbie. There are lots of little things that have to be done right, to keep the whole thing from becoming land fill material. One slip, and you could easily destroy a driver that is scarce to find.

And it continues................

[Wayner]

I thought some caps were coming, but apparently not, so I cannibalized another old project and found some 12mdf caps. I had some 8mfd, so that makes 20. In they went. I also covered up all the cross-over circuits before repacking the wadding, to keep the wadding out of the level control.

 

 

I had just got them in place when the bride came home. She poured herself a nice glass of wine and came down to the studio for a listen. I had the FM going, and I thought to myself that it was kind of boring, no stereo, kind of like mono.

I use 3/4" wide masking tape to mark and align speaker positions on the shelf. They are there permanently. The ARs went in the middle position, normally where the Advent Model 3s went. Well, I got up and moved each speaker outward, the width of the tape, or 3/4" over with both speakers, so now that's an inch and a half, and the wife said, we just went into stereo mode! Sure enough, the entire stage changed, and changed drastically. We had found the sweet spot.

I don't claim to fully understand what goes on here, finding the sweet spot, but it's happened with all of the speakers. One thing for sure is what I call a "pressure ridge" created by the woofers. I believe that when speakers are too close together, the air pressure created by the woofers, blocks high frequencies. Moving the speakers father apart, always seems to fix this problem.

This is another reason why I don't understand why some people put their speakers along the short wall. To me, this is so wrong in so many ways, the above reason being number one, but the short wall location also invites second and 3rd reflections, turning the listening experience into a blur.

Wayner

[dB Cooper]

Well, just like one can conduct a "knuckle" test on an enclosure, one can also "flick" a stamped or cast woofer frame and easily hear the difference. Stamped frames kind of have a tinging, clinking sound to them. Whenever I use woofer with a stamped basket, I'll finger flick it and if it rings, I'll apply some of that peel and stick damping sheet material to the basket.

Plast-i-clay on the stamped speaker baskets, as recommended by Frank Van Alstine, works probably just as well or better for a fraction of the cost. Bet it would dramatically improve the little ARs.

I'm getting a major nostalgia buzz off these btw, wayner.

[dB Cooper]

Follow up thought, I wish acoustic suspension would make a comeback, but somewhere along the line, a port became a "must-have" selling point to John Q. Public, rather than a design approach that has advantages and drawbacks, like every design approach does. Only brand I am aware of still using this technique is NHT.

[Æ]

Plast-i-clay on the stamped speaker baskets, as recommended by Frank Van Alstine, works probably just as well or better for a fraction of the cost. Bet it would dramatically improve the little ARs.

I'm getting a major nostalgia buzz off these btw, wayner.

I have and have used non-hardening modeling clay also. I prefer the peel and stick variety simply because it is neater and looks cleaner. I buy generic sheets from Parts Express, not very expensive at all.

[Æ]

Follow up thought, I wish acoustic suspension would make a comeback, but somewhere along the line, a port became a "must-have" selling point to John Q. Public, rather than a design approach that has advantages and drawbacks, like every design approach does. Only brand I am aware of still using this technique is NHT.

The problem with "acoustic suspension" is the distortion, especially when using a small woofer. If you try and squeeze too much bass out of it at some point the distortion becomes gross distortion.

I'm not absolutely sure about their efficiency, but I'm thinking that woofers designed for acoustic suspension aren't all that efficient either, they have long throw, overhung voice coils, never a lot of turns in the gap.

[Wayner]

I think the main problem with acoustic suspension speakers is a misunderstanding of the nature of the beast. They are not made to play at concert levels. If you want that, go buy some JBLs or Cerwin Vegas. They are made to produce incredible, life-like bass and an incredible sound stage at lower volume levels, with a much smaller cabinet, than is required for a ported speaker. This was Edgar Villchur's goal from the beginning.

Last night I played a couple of LPs into these speakers: Dead Can Dance-Spiritchaser and Andreas Vollenweider-White Winds. The imaging was superb and when the musical content for bass was appropriate, they actually startled me a couple of times, especially on side 3 of DCD. I have the tweeter level at about 3/4 open. Both drivers blend very well. I thought the tweeter might be a little "cheezy", but it is infact, impressive.

Wayner

[doug s.]

hi wayner,

congrats on a great yob w/your speakers!   

a few questions/comments about soundstaging.  i think most folks place their speakers on the short wall because in the vast majority of cases, you will get better soundstaging - that's why so many folks do it.  if the room is too narrow, you may have sidewall reflection issues, but this can be addressed w/absorbtion at first reflection points - placing the speakers on the long wall of a wery narrow room means your back will be up against the rear wall, which is even worse, in most cases, than having speakers close to side walls.

also, when you audition your speakers, are they as shown in the pics?  that close to the rear wall?  other speakers adjacent?  unless speakers are specifically designed to be tight to the rear wall, they will always soundstage better out into the room.  and, it's been shown that having other inactive speakers nearby will negatively impact soundstaging and tone, as the inactive speakers will wibrate and add their own sound, due to excitation by the driven speakers.

ymmv,

doug s.

[Russell Dawkins]

FWIW, my experience has led me to always try speakers on the long wall first, as that usually sounds best to me. I cringe whenever I see speakers close to side walls in a narrow room: I have never heard a pleasant sound yet under those circumstances - it seems as though breathing room to the sides of speakers may be more important than breathing room behind.
More off topic, I am surprised that so few speakers are specifically designed to work with wall reinforcement. Seems to me that would open up possibilities for typical home use. This also may be why the AR-4X works in that placement - sealed boxes have predictable smooth shallow roll-offs in the bass, rather than the precipitous plunge following the resonant hump of the typical reflex. The roll-off of the sealed box is more like the inverse of the wall reinforcement. Roy Allison used this to good effect in some of his designs.

As to the other speakers reacting, this can be helped a lot with shorting links across the terminals of the unused speakers. This damps the woofers' resonances.

[Æ]

As to the other speakers reacting, this can be helped a lot with shorting links across the terminals of the unused speakers. This damps the woofers' resonances.

Totally awesome suggestion, one that really works. Wonder why I didn't think of it.

[doug s.]

FWIW, my experience has led me to always try speakers on the long wall first, as that usually sounds best to me. I cringe whenever I see speakers close to side walls in a narrow room: I have never heard a pleasant sound yet under those circumstances - it seems as though breathing room to the sides of speakers may be more important than breathing room behind.
More off topic, I am surprised that so few speakers are specifically designed to work with wall reinforcement. Seems to me that would open up possibilities for typical home use. This also may be why the AR-4X works in that placement - sealed boxes have predictable smooth shallow roll-offs in the bass, rather than the precipitous plunge following the resonant hump of the typical reflex. The roll-off of the sealed box is more like the inverse of the wall reinforcement. Roy Allison used this to good effect in some of his designs.

As to the other speakers reacting, this can be helped a lot with shorting links across the terminals of the unused speakers. This damps the woofers' resonances.

yust to be clear - i am not talking about breathing room behind the speakers so much as breathing room behind the listening position.  while i agree that having speakers close to side walls is not good, ime it is preferable to having the listening position directly against the back wall.  the reflection off a wall directly behind the listening position is harder to ameliorate, imo, than reflections off side walls.  of course, experimentation is best.

and, i agree - it is surprising more speakers are not designed to work with rear-wall reinforcement.  some, tho, are specifically designed w/this in mind...

and i second the suggestion of shorting unused speaker's drivers - it seems this would help reduce unwanted output from them.

as always, ymmv...

doug s.

[Wayner]

Thanks for your input. The Studio is a very small room in the lowest level of the house. At one time it was my personal recording studio. Now it serves as the vinyl room. As you may have noticed, all of my speakers in the studio are of the "bookshelf" variety. They love being on the shelf, but each one is in a very specific position, and toe-in angle(s) as they demanded it of me, to produce the huge, 3D soundstage that they do. The studio is in fact, a giant live in set of headphones, as my bride and I listen to everything in near-field. While the speakers are in slightly less then desirable positions, the near-field experience more then makes up for the situation.

Frank has been here and I think was very impressed with the sound this room produces. The lesson is that almost any room can be tamed, if you are diligent on your methodologies.

Each speaker set has it's own amplifier. One set of speakers can be set to two different amplifiers. There are 2 separate preamplifiers that can run any combination of amps. There is also a 3rd, all tube preamp, that is occasionally brought in. Each preamp has it's own phono board, and I also have an all tube AVA phono preamp, that has only one brother.

We also sport 3 FM tuners, 4 turntables and a reel-to-reel and CD recorder. Three separate dedicated branch circuits feed the rooms power and we also have LED and Incandescent dimmed lighting.

The room comfortably seats 2. In my glider, I can swivel around and have access to about 1000 albums, that are my favorite. In the next room is the other equpment room with another 3000 LPs and 4 more turntables, and some more amps, preamps, receivers and my workbench, where I build the Longhorn phono cartridges.

If there is any interaction with other non used speakers, it's not much, nor is it a problem, as the music in this room is not "blasted",nor is it necessary. We can (and do) play things rather loud at times, but for the most part, this is a very mellow and personal listening room.

The AR-4x speakers fit very well into the scheme of things.

Wayner

[Quiet Earth]

I am surprised that so few speakers are specifically designed to work with wall reinforcement. Seems to me that would open up possibilities for typical home use.

Pretty sad state of affairs that something meant to be enjoyed in the home is not designed for home use anymore. If you are going to cringe about anything in this hobby, that should be it.

I personally like the side walls, but I don't use modern (trendy) speakers anymore.

[doug s.]

sounds like a wery cool set-up, wayner.  and yes, i agree - w/nearfield listening, many otherwise "normal" acoustical issues go away...

doug s.