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stixstudios

On-The-Couch: "Confessions of a Low Range-Audiophile"

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On 01/02/2019 at 1:38 AM, stixstudios said:

 . . . During testing, a small 10x10mm piece of foam rubber fell out of the woofer that already has a cracked surround. So, that's it for loud testing in case I make it worse by screwing up the coils or something else . . .

Well, during the "thunderstorm Test", I almost did screw up something else.

 

I had the grill/cover over the other speaker that I thought was ok and was concentrating on the speaker of concern. The next day/s I pulled the cover off the other one and realised that one of the woofer surrounds was cracked approx. 1/3 of the way around. Ouch!!!

 

Today, although I didn't want to, I removed all 4 woofers. I wanted to check that no damage had been made to the coils. I tell you it was hard to start slicing through the surrounds with my stanley knife knowing there was no return. But it had to be done.

 

With the surrounds removed I was able to do a simple test by carefully pushing down on the cone. No scraping thank God, but the coils on these speakers are very tight around the pole piece. They are not damaged, but the small tolerance is by design.

 

So now the 508A's linger in hibernation, and I've had to re-instate my old Linear Phase 8812 Monitors (the "White Van" versions). Needless to say, the difference is like night and day.

 

I've ordered some replacement surrounds from the US. I'm going to carefully "prep" the speakers, ie. carefully remove the old glue/gunk (to help limit the costs).

 

Cheers.

 

 

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You shouldn’t be playing speakers until repaired especially at loud volumes.

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Yeah, I know AI.M, but it sounded so good I couldn't help myself. :) I knew it would happen, luckily no extra damage done (I don't think).

 

I'm currently prepping the speakers by removing the surrounds and cleaning the cone up etc.. I'll see how it goes, I may even attempt to replace the surrounds myself. <gulp>.

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It’s not so hard DIYing surrounds on woofers. Google it. Get an extra set incase make a mistake and start over.

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Done the googling enough. These woofers are not run-of-the-mill. Angled "under" surrounds" and non-standard plastic "over-surrounds".

 

On the first speaker I removed a gasket that I probably shouldn't have. It can be fixed though.

 

It's taken me many hours to prepare these, and it's looking pretty good. When the "surrounds" arrive from the USA, then I'll give it a crack, otherwise I'll get a professional to do it.

 

Yes, it would have been good to order 2 more (these need 4. That is 2 in each cabinet). I may as well have done so considering the postal cost.!!!

 

It's going be a huge task, but I'm looking forward to the challenge. I give myself 93% success, 7% fail. If I screw up, that would really piss me off. Nice original woofers (re-furbished) in original boxes.... aaarrrrggghhhhhhh!!! :) :)

 

 

Edited by stixstudios
Reason: Accidentally dropped my beer on the floor, then fell over looking for it. Apologies for the delay.

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What I find works for me in roll surround replacement, dont go the trouble of taking off dust cap, instead glue the woofer cone to surround first let it dry. Lineup woofer position to coil making sure its not rubbing, keep some pegs clamped to basket frame edge while gluing the one side then move around to other side and clamping it gently. Test for fit and coil alignment by gently pushing cone in and out.

Edited by Al.M

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Ron Newbound, take your speakers to him, guy is a gentleman, you won’t the regret it, doesn’t rip you off and does an amazing job.

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Cheers AI.M, Yep, I agree with everything you just said.

 

I don't have replacement dust caps anyway, so removing them and using shims could possibly screw them up.

 

I was just talking to my brother about the best way to attach the surrounds and we both agreed that using pegs as you suggested above, would be a good way to approach it. Sort of like a tack-weld situation.

 

I've finally finished prepping them. I'd guess it took me around 2hrs for each - softly softly, I took my time. I could have got similar replacements (kevlar), but NO, I want to try and take them back to their original condition.

 

As a side note, I mentioned in an earlier post that these 508A's tend to sound a bit "splashy". During the "thunderstorm" testing episode, I fiddled with the variable loudness control on the Yamaha A-S701 which "scoopes" out a bit of midrange and was able to remove, or at least control the sound to a point which I was very happy with.

 

What that means is it was not the treble (tweeter) causing the offending frequency, but the mid-range which is a 2 inch titanium speaker. Which I still reckon seems more like a "squawker".

 

I'm looking forward to getting the surrounds and replacing them. If they sound as good as they did (and they bloody well should sound better at the low end) then I'll be very very happy. These are pretty damm good speakers in my view. Hopefully I don't destroy them :).

 

Altec Lansing 508A's.jpg

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Regarding the spalshiness, the likely driver crossover freq of a speaker using small mid dome is maybe something like 500-1000hz from woofer to midrange and 5000-6000hz+ maybe even higher, it may be coming from a combination of tweeter and midrange driver response. Without access to sound measurements perhaps find the resistor feeding the tweeter and increase its value by about 20% to reduce intensity and play around.

 

Subjectively, without placing your grandmothers inheritance on any bets, many would say the metallic domes can tend but not always sound splashy or ringing. An upgrade or refresh of capacitors in the crossover circuit might also help as the speaker is quite old now and values may have drifted as caps can dry up over time.

Edited by Al.M

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Thanks for the good advice.

 

The whole thing hinges on the "refurbishment" of the woofers. I'm not completely sure about the new surrounds I've purchased. There are some measurement discrepancies between the diameter of the cone. These surrounds are glued under the cone on the inner side. Hard to explain, but the up-shot is I won't really know until the surrounds are in my hands.

 

The surrounds I purchased are for 8" Altec 508's, which I have "assumed" are the same as the 508A's. Dunno, because there is NO freakin' info out there. The Altec Lansing Heritage Forums are only interested in pre-1975's stuff. Fair enough, but that leaves me in no-man's land, and I'll just have to deal with it as it comes.

 

No big deal, as there has been no great investment of monies, but nevertheless, a big investment of my time. I really do want to get these speakers back to what I heard before, and back to original condition.

 

One does wonder however, if when the original rubber surrounds deteriorate and become a bit hard, then pushed to a limit, then they deliver some nice "punchy" bass. Yummmmm....

 

Who knows what the future holds, only a fool would say. :)

 

Well, I hope to get the surrounds in the next week or so, then perhaps the fool will be in a better position to say, Inhe?

Edited by stixstudios

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Finally after a lot of careful planning and "fly by the seat of your pants" moments, all 4 woofers have been repaired. A few minor glue splotches here and there at the edges that I would rather not have (for aesthetics), but job done, and no voice coil rubbing and no "physical" distortion.

 

I haven't driven them properly yet - best to ensure that the glue has dried fully. But at this point a big improvement (especially on the bass). :)

It's been about 2 days since the final gluing stage - the glue apparently dries within 1hr anyway, so I may well crank it up tonight.

 

I did have a look at the crossovers and couldn't see any sign of leaking caps, they looked as new as the day they were installed, so I just left them as they were. Apparently the speakers were in storage for quite some time, so although the original rubber surrounds had degraded (time issue) the electronics would be more likely to degrade from usage, not time?

 

Anyway, at this point all is looking good. I guess I'm still a bit scared of cranking them up just in case a huge bass note causes the cones to fly out of the cabinets!! Well, I hope not.

 

Cheers, Steve.

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Hi Steve. Just wondering how much your speakers are worth? Could you be better off using part of your budget to buy another pair of second hand ones?

 

Sounds like a lot of time and effort is going into the repair. Repair bill won’t be cheap either. If it takes a couple hours that’ll probably be a few hundred dollars minimum. 

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Hi Mike.

 

I've already repaired the speakers my self. If I had to pay someone else to do it, then it probably wouldn't be worth it. I think they cost around US$1100 new in 1995, so in todays money around 3 grand??

 

They sound fantastic to me. :)

 

[EDIT] Forgot to mention. All up including the repairs, they cost me around $350.

 

Cheers.

Edited by stixstudios
Further info.

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Nice one! It is great to read about people’s journey to musical happiness that don’t simply involve throwing more money at the problem. 

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On 26/02/2019 at 12:09 PM, Juzbear said:

Nice one! It is great to read about people’s journey to musical happiness that don’t simply involve throwing more money at the problem. 

 

Thanks Juzzy. ... Ummm . . . Well . . . I'm back on the couch again!!!

 

I just bought a sub-woofer to the extend the bass a bit. I did previously mention that I wasn't completely convinced that I was getting the bass response that I wanted/needed, and therefore surely the sub is justified :)

 

Just that little bit of low frequency helps for sure.

 

Everything is fine now, and no need to "improve" the sound anymore. All is good. Although perhaps a valve/tube pre-amp could increase the . . . . . .

Edited by stixstudios

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