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Gear / Technical Help => Playback Forum => Topic started by: kindms on November 16, 2020, 01:23:47 PM

Title: TSKB: Speaker restoration
Post by: kindms on November 16, 2020, 01:23:47 PM
So rocksuitcase has a pair of these Altec Lansing speakers

(http://www.lansingheritage.org/images/altec/catalogs/1993-pro/1993-37.JPG)

Pretty sure these are 310 or 312

Any way I have built a kit before but have never done any refoaming or etc. Anyone with some tips on where to start ? Do they look like they can be salvaged or would just reusing the cabinets be worthwhile / better ?

(http://www.blueberrydreams.com/images/altec1.jpg)
(http://www.blueberrydreams.com/images/altec2.jpg)
(http://www.blueberrydreams.com/images/altec3.jpg)
(http://www.blueberrydreams.com/images/altec4.jpg)
Title: Re: TSKB: Speaker restoration
Post by: Gutbucket on November 16, 2020, 02:06:10 PM
Looks to be an early 80's era speaker that was in production through the early 90's- http://www.lansingheritage.org/images/altec/catalogs/1993-pro/1993-37.JPG

Refoaming is pretty easy, or at least it was when I last did it 25 years ago to fix a pair of mid 80's era Infinity's (Infinities?).  Might be worth trying that just to get a taste of how they are before making the decision to go further or not.

Title: Re: TSKB: Speaker restoration
Post by: rocksuitcase on November 16, 2020, 09:45:34 PM
Thanks kindms and gut.
we received four these from Altec Lansing in 1986 as part of our deal to research hoping to manufacture our surround sound effects processor. They were used at the time for side or rear speakers in early theater Dolby arrays. They were part of our research, then my stereo for another ten years. Had been sitting in grandma's attic for years. We used to power them with Crest Amps....yum
Title: Re: TSKB: Speaker restoration
Post by: Gutbucket on November 17, 2020, 09:55:19 AM
Don't mean to take the thread too OT, but I'd love to hear more about that surround sound processor.

I had a Yamaha DSP1 in the mid/late 80's and used it for all kinds of interesting stuff.  As one of the first general outboard DSP boxes it suffered something of an identity crisis, being partly targeted at hifi ambience extraction and recreation, partly at early pre PLII era Dolby Surround, and partly at effects for musicians and mixing.  It had four outputs which could be used to feed speakers placed in the upper corners of the room, and an accompanying 4 channel power amplifier.  It didn't have much bit resolution and had a rather high noise floor, but the algorithms were very good for the time.  I'd use it for music making mostly as a 4ch Lexicon type verb, 3d swirly phaser/flanger guitar and organ effects, and vocal chorusing/pitch-changing stuff.  It was great fun at parties, switching roles between eye-opening unexpected mind-expansion of whatever music was playing (it was predecessor to the later ubiquitous and generally terrible "hall" preset modes built-in to home theater receivers, except way better implemented) which would morph into panning and swirling our own jams all around the room.  After a day's field trip out to the cow pastures, later totally displaced by housing developments, we'd come home, boil up some tea, open all the windows and let the music diffuse out into the thick air of a warm summer night.  Good times.

As I recall, the modulated pitch-changer in combination with a cheap DAK digital delay unit in a loop-back arrangement was capable of forming a vortex that could cause the floor to dissolve away revealing a bottomless cavern reaching all the way down to the center of the earth.  It took a fine hand on the controls to ease intrepid travelers safely back to the surface without subjecting them to too much psychic-g-force.
Title: Re: TSKB: Speaker restoration
Post by: Numpy on December 09, 2020, 06:29:10 AM
Was it 32bit?
Those early ones didn't have enough bits.
<Cheesey grin, +T if you can name the movie that I'm riffing from>
Title: Re: TSKB: Speaker restoration
Post by: kindms on December 09, 2020, 06:33:20 PM
Re-coned them earlier today and currently jamming some dead on them

(https://scontent-bos3-1.xx.fbcdn.net/v/t1.0-9/130096908_10213935921112393_2360121263763065211_n.jpg?_nc_cat=103&ccb=2&_nc_sid=8bfeb9&_nc_ohc=j-5oqTznHRoAX_XGcuh&_nc_ht=scontent-bos3-1.xx&oh=e3083bd1a14805fe9a73a6a5b1ab6476&oe=5FF7AD22)

(https://scontent-bos3-1.xx.fbcdn.net/v/t1.0-9/130290378_10213935921832411_8997442497003224589_n.jpg?_nc_cat=109&ccb=2&_nc_sid=8bfeb9&_nc_ohc=8fUsgWqItEcAX_4dNj5&_nc_ht=scontent-bos3-1.xx&oh=d8f5db62a6d14dea3f692683ee2981c8&oe=5FF86A0F)

(https://scontent-bos3-1.xx.fbcdn.net/v/t1.0-9/129976749_10213935921192395_2422023169097017439_n.jpg?_nc_cat=101&ccb=2&_nc_sid=8bfeb9&_nc_ohc=nM7dcbTZ00gAX8lm1jJ&_nc_ht=scontent-bos3-1.xx&oh=fcac29e835d7b80971b90467744c19b0&oe=5FF66F42)
Title: Re: TSKB: Speaker restoration
Post by: Numpy on December 10, 2020, 02:32:58 AM
Re-coned them earlier today and currently jamming some dead on them

(https://scontent-bos3-1.xx.fbcdn.net/v/t1.0-9/130096908_10213935921112393_2360121263763065211_n.jpg?_nc_cat=103&ccb=2&_nc_sid=8bfeb9&_nc_ohc=j-5oqTznHRoAX_XGcuh&_nc_ht=scontent-bos3-1.xx&oh=e3083bd1a14805fe9a73a6a5b1ab6476&oe=5FF7AD22)

(https://scontent-bos3-1.xx.fbcdn.net/v/t1.0-9/130290378_10213935921832411_8997442497003224589_n.jpg?_nc_cat=109&ccb=2&_nc_sid=8bfeb9&_nc_ohc=8fUsgWqItEcAX_4dNj5&_nc_ht=scontent-bos3-1.xx&oh=d8f5db62a6d14dea3f692683ee2981c8&oe=5FF86A0F)

(https://scontent-bos3-1.xx.fbcdn.net/v/t1.0-9/129976749_10213935921192395_2422023169097017439_n.jpg?_nc_cat=101&ccb=2&_nc_sid=8bfeb9&_nc_ohc=nM7dcbTZ00gAX8lm1jJ&_nc_ht=scontent-bos3-1.xx&oh=fcac29e835d7b80971b90467744c19b0&oe=5FF66F42)

Images not coming through
That's fast drying glue !

How do they sound ?
Title: Re: TSKB: Speaker restoration
Post by: rocksuitcase on December 10, 2020, 08:46:49 AM
OK, A little background. These speakers are Altec Lansing 312's. they were designed to be surround or rear speakers in small to medium theaters. They were designed in the late 1970's but we were given four of them by Altec's engineers in 1985 in order to do the research on our patented signal processor. Altec obtained the rights to retail the surround processor and we only sold about a dozen before going out of business due to personal differences. But I digress.

These speakers were designed to be very efficient, used on side walls, flush mounted or hung on the wall. The woofers are solid, 12 inch, nice bass response. The tweeters aren't the best, but they weren't designed for incredible high end, surround signals being less prevalant in the high frequencies.I believe they have a passive crossover which cuts off about 140 Hz. I am inspired my buddy did the DIY job to keep these old speakers alive!

I have documents and should open a new thread when I get to discussing the Tri-Ambient synthesis surround processor.
Title: Re: TSKB: Speaker restoration
Post by: kindms on December 10, 2020, 10:43:18 AM
Re-coned them earlier today and currently jamming some dead on them


Images not coming through
That's fast drying glue !

How do they sound ?

Cure time was an hour according to the instructions but it sets up pretty fast. so 1 hour for the cone, 1 hour for the frame. and 1-2 hours if regluing the original gasket which I did. it comes with an optional foam sealer as well that I did not use (yet).

They sound good. I was using my kit bookshelf speakers which i really like. The Bass difference was of course immediate. but overall for the age and some not so great storage the fact they play at all is awesome. But they sound great to my shitty ears. not hearing anything so far that i would call failure of the speaker components etc.

They do throw some sound.

got my repair kit here

https://www.simplyspeakers.com/

Based in St Petersburg FL
Title: Re: TSKB: Speaker restoration
Post by: Gutbucket on December 10, 2020, 11:08:52 AM
Cool that the new surrounds were a relatively easy fix, without any voice coil centering problems. 

I have documents and should open a new thread when I get to discussing the Tri-Ambient synthesis surround processor.
^
Looking forward to this when you do.


Somewhat pertinent to both topics, I've had lots of fun over the decades adding pairs of old speakers like this to standard stereo setups using the good old "Hafler circuit" difference-wiring technique.  Fun to play with and works well for a lot of stuff.  It's simple. All it takes is a couple extra speakers and three long sections of single conductor wire. 

It sends the L-R difference signal (the Side signal in terms of Mid/Side) to the extra speakers, so only the stuff that produces level or phase differences in the two channels goes to them, with level determined by how strong that difference is and the sensitivity of the speakers.  With good live recordings, much of that difference signal tends to be the ambient audience and room sound - the non-direct-sound "you are there-ness".  With a mono source they remain silent.

I found pointing the extra speakers toward the walls, ceiling or back corners and away from the listening area often helped to diffuse the sound more evenly, create a longer path to the ear so the image doesn't pull away from the front, and helped reduce the level from them to something more to optimal.

It's a long time favorite thing to do when a friend says "check out these old speakers I came across.. don't know what I'll do with them though", and really spices up crappy second-hand garage and shop stereos especially well, filling the space with sound.  Even rather crappy speakers work well.
Title: Re: TSKB: Speaker restoration
Post by: Gutbucket on December 10, 2020, 11:16:21 AM
^
I recall a couple old Brian Eno albums suggesting it, with instructions and a wiring diagram printed on the back cover.  I think those indicated using a single extra speaker instead of a pair, but I found it worked better with two as indicated in the diagram above.
Title: Re: TSKB: Speaker restoration
Post by: Craig T on December 10, 2020, 02:12:51 PM
got my repair kit here

https://www.simplyspeakers.com/

Based in St Petersburg FL

I drive by that place all the time and wondered what they were about.  Nice work on the speakers!