genek

It's MDF. HDF is the stuff they make perforated pegboard out of.

Many thanks to member Dave S. for providing this bit of AR/Teledyne history. Teledyne 1980 Q2.pdf

There really aren't any "rules" for selling something here on CSP. Describe the items as best you can, tell people where you are and set a price. For a reasonable amount, there will probably be someone willing to come get them who will actually want to restore them and won't just replace drivers with boom box woofers and cheap tweeters to flip them on Craigslist or eBay.

Another alternative when you run out of attachment space: in the lower right corner of the posting dialog is the "Other Media" dropdown, and one of its options is "Insert image from URL." You can upload images to a pic hosting site like imgur.com and then insert their URLs and they'll appear here. The image below is uploaded to imgur.com. It's 3840x2160, 7 Mb, and takes up no space on CSP.

Could be time to think about restocking.

If the veneer on a 30+ year old cabinet is in good shape, it's probably going to be higher quality than consumer veneer today (that's paper-backed stuff that comes packaged in rolls at your lumber store). So if the drivers and crossover fit without too much hacking at the cabs, it might be worth the effort.

It's this one: https://ulsterlinen.com/?s=Y0400NT036+&post_type=product The last three numbers are the width (36, 42 or 60 inches).

I ordered a yard of my best pick from Ulster Linen. It arrived this week and if I can figure out what I did with my staplegun (which I haven't seen since before we packed up to move to Portland eight years ago!) I have a spare pair of 3a frame boards I can mount it to. It's undyed, unbleached natural flax linen. We figured out a while back that it's 20ct. Here's what the loose yardage looks like.

What I'm wondering is if someone tried to hack the crossover to make the side-firing mid work without the MGC amp.

Does it look as if the side mid and the added resistors have been rewired to be in series or parallel with the front-firing mid? I'm wondering if perhaps someone who didn't have the MGC amp rewired the speaker so the side-firing mid would produce output from a regular stereo amp.

I wonder if they might have been reconed. Hard to imagine someone going to the effort to take the P/N on a woofer that's going to be out of sight when the speakers are closed up.

Did you find out what's under the black smudge on the woofers?

Our resident experts here at CSP concluded quite some time ago that there are pretty much no available new woofers that are suitable for use in acoustic suspension speakers (including those being marketed as AR replacements). But it's good to see it being said outside of our little corner of the world.

I'd put some cleaner to the black smudge and try to see what's under it.

Try the seal first and see how you like the sound. You already have the woofers AR would have provided as replacements back in the 1980s.

These are the woofers AR listed as replacements for the 18 series in 1986. The label says they're US made, so they're not Tonegen. Is there a gasket under the woofer? If not, you don't have a seal. Even if there is a gasket, it may be too compressed to seal well. Try some new foam tape or sealing putty and see what that does.

The idea behind the MGCs was to create simulated ambience by shooting delayed signals out the sides of the speakers that would bounce off side walls. The MGC-1 had respectable 2-way woofer/tweeter side pairs, but the MGC-2 only had a single bass/midrange driver. For both models, the processor allowed the delay to each side to be separately adjusted to compensate for asymmetric listening spaces. In the absence of the original processor electronics, I think what I would do with an MGC-2 is just hook up the main front-firing set as the FLR pair on a HT surround unit and instead of trying to feed something to the side-firing driver, use some other ARs of the same period as surrounds and the front center channel.

AR moved to Norwood in 1973. My 1975 2ax speakers are from the last Norwood run of that model, with MDF backs and labels like the one in the photo, and they had all backwired drivers. I've also seen 3as with the same back, label and backwired drivers. These 3as still have front wired terminals, so they're not from the last run. Maybe 1973-1974. The back wired tweeter with the front lead is either an AR replacement or a later repair. Hopefully, it's the proper driver and not an 8ohm, but there's no way to tell without checking impedance or looking for a P/N on the back.

It's clear from what simonsounds says above that the UK did serials on pairs differently from what AR did in the USA.

Just to make things as confusing as they can possibly be, I have two pairs of AR-1ms. In both pairs, the speakers have the same serial number.

Moving to Library Additions and Corrections. Have you contacted Mark about this? The issue is more about Mark's time than site hosting, so any alternative proposal would need to include site authoring and management. And CSP is not a democracy; any decisions about its future would be Mark's alone to make.

If anyone has any concrete proposals to offer and has the web authoring chops to actually do the work - suggest you click on the Contact link on the site homepage and send a message direct to webmaster (that's Mark). I don't think he has time to read the forums much anymore.

Unfortunately, right now it just adds to the backlog. Best to hang onto them until (hopefully) Mark is able to figure out a path forward for the library.

Our site owner doesn't have the time to work on it.

If we ever get the ability to update the library again there's a huge backlog of this stuff. PDF attached that should be a little easier on the eyes. AR-1 Audio-1955-Jul.pdf