My new-to-me 820s

**Audio_by_Goodwill** · March 16th, 2013, 04:28 PM

What would it look like without grill cloth?

**wws944** · March 16th, 2013, 07:12 PM

Originally Posted by Audio_by_Goodwill

What would it look like without grill cloth?

Unacceptable to my wife, in any case. She is barely tolerating the fact that they will be in our home thea^h^h^h^h^h^h^h^h um living room... ;-)

Not sure what happened to the dresser, lamp, and that nifty black radio. I wonder if they made it with my uncle to California way back when? Will have to ask my cousins. I think he must have gotten rid of that white Zenith record player decades ago.

Originally Posted by Alien_Shore

Not sure about the grill cloth, other than I totally agree that you should replace it!

How cool would it be to have a thread of old pics showing new vintage gear in it's prime. That picture is a fantastic example.

We have a few more photos from the '60s and '70s that have his hifi gear in the background. Didn't want to bore you guys though.

**wws944** · March 17th, 2013, 03:27 PM

Looking at Antique Electronic Supply, the "Oxblood/tan" grill cloth looks very '50s retro and apropos. The page for it Grill Cloth, Oxblood/Tan 34" Wide | Antique Electronic Supply says it is for Fender guitar amps.

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At the Newcastle/Acoustone web site, http://www.acousticalsolutions.com/5...-speaker-cloth, none of the speaker grill cloths look right. However a couple of the ones for amps, http://www.acousticalsolutions.com/a...htbox/prod_492, seem closer. I wonder if their P211 is the same or very similar to what I am looking for? Five yard minimum order though. I figure I only need three yards.

Newcastle/Acoustone P211:

217H5246 3

**wws944** · March 19th, 2013, 04:03 PM

Update: Talked with Acoustone today. They were very helpful! He is thinking the Acoustone P102 is the match, and is sending me a sample. BTW, the "-72" in the grill cloth spec in the Badmeiff & Davis book refers to 72" wide material. So at least that mystery is resolved. Here is what P102 looks like:

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**wws944** · April 8th, 2013, 11:51 PM

Update: I have obtained a bunch of swatches of grill cloth - both from Acoutical Solutions and from another distributor. Also we discovered something interesting. I knew that one of the main grills had newer cloth than original, but it turns out they both match each other. So I guess my uncle did both. But they don't match any of the samples I have. Now here is the interesting thing: The bass reflex ports, which are hidden below the main grills down by the floor, still have original grille cloth! And it looks to be an exact match to the P211 pictured a few posting above!

Unfortunately, what was purported to be a swatch of P211 from the distributor, does not exactly match what is on the reflex ports. So now I need to obtain a swatch of 'real' P211 from Acoustic Solutions for comparison...

Another tid bit - as mentioned in post #44 and others, the Badmeiff and Davis book refers to "211-72 Aluminum". Still not sure how the "Aluminum" comes into play. But we measured the bass reflex port and it is nearly 40" wide. So it seems that 72" wide cloth is definitely necessary to get the orientation of the lines in the cloth correct.

**Alien_Shore** · April 9th, 2013, 01:43 PM

So what did you decide to do about the crossovers and drivers?
Are you going to get the Alnico recharged? Are the voicecoils in good shape, or are you going to replace the HF diaphragms? You going to refurb those old series crossovers, or go with a parallel design?

**wws944** · April 9th, 2013, 07:38 PM

I intend to keep the original drivers. Once I get everything back, I will do a lot of listening and testing on them.

Not sure what to do about the crossovers yet. First step, of course, is to measure the caps to see how out of spec they are. I talked with Bill at GPA a few weeks ago. He was recommending raising the crossover frequency to 1200 hz.(*) So that says I should probably abandon the original crossovers and just build new ones. Or perhaps I could bi-amp them. An active crossover would cost about what a pair of decent quality passive crossovers would, and I already have the amps.

Bill thought I probably made a mistake getting the cabinets refinished, value-wise. It was a really hard decision for me. But the 1955 cabinet did need a lot of work. And if I just did it, then the 1957 cabinet would look bad by comparison - as it had its flaws too. (If they had both been in the condition of the 1957 cabinet to begin with, I wouldn't have touched them.) Asian collectors can mourn. But I intend to keep these until I no longer can. So in the end, the tough choice became clear. And I am staying true to the era by using lacquer instead of polyurethane. I think my uncle would be happy with the results.

(*) This running a 15" woofer at 1200 hz thing does bother my sensibilities a bit. Back in the 1970s, when I bought my ML-1Cs, I read Roger Russells white paper on their design. His design rules included keeping the cones very stiff, and importantly, small in diameter WRT the wavelength of sound each driver was expected to reproduce. This to avoid cone breakup modes and beaming. He only ran his 12" driver up to, as I recall, 250 hz. Then the 8" driver took over. Of course he was designing for a sealed box and using a woofer with much larger excursion than the high efficiency Altec setup with bass horns. Also with the 820s sitting in corners, perhaps beaming is less of an issue. All part of the 'art', I guess...

**Altec Best** · April 10th, 2013, 03:45 AM

Originally Posted by wws944

Update: I have obtained a bunch of swatches of grill cloth - both from Acoutical Solutions and from another distributor. Also we discovered something interesting. I knew that one of the main grills had newer cloth than original, but it turns out they both match each other. So I guess my uncle did both. But they don't match any of the samples I have. Now here is the interesting thing: The bass reflex ports, which are hidden below the main grills down by the floor, still have original grille cloth! And it looks to be an exact match to the P211 pictured a few posting above!

Unfortunately, what was purported to be a swatch of P211 from the distributor, does not exactly match what is on the reflex ports. So now I need to obtain a swatch of 'real' P211 from Acoustic Solutions for comparison...

Another tid bit - as mentioned in post #44 and others, the Badmeiff and Davis book refers to "211-72 Aluminum". Still not sure how the "Aluminum" comes into play. But we measured the bass reflex port and it is nearly 40" wide. So it seems that 72" wide cloth is definitely necessary to get the orientation of the lines in the cloth correct.

I read a Altec sheet before, can't find it ATM though. But the aluminum color was one of 2 offered the other was blond.I think it may have been on the Laguna.And was from Newcastle Fabrics.

**wws944** · April 10th, 2013, 10:20 AM

Originally Posted by Altec Best

I read a Altec sheet before, can't find it ATM though. But the aluminum color was one of 2 offered the other was blond.I think it may have been on the Laguna.And was from Newcastle Fabrics.

Perhaps you are thinking of the 820 cabinet plans in the Badmeiff & Davis book?

The grill cloth portion is:

Interestingly, the plans above don't show the bass reflex port. So it is something a home builder would likely overlook - unless he had a real 820 available for comparison.

**Altec Best** · April 10th, 2013, 10:27 AM

Yes I have that book too.Could be. But my recollection was on one of those pink Altec sheets... I'm pretty sure I saved it.. I just have so much stuff I can't find it now.And I recently had an external hard drive crash on me that I can't access so it could be on that one.