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Looking for some more info on Altec 816A's

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URL: https://forum.speakerplans.com/forum_posts.asp?TID=13288
Printed Date: 28 March 2024 at 6:09pm
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Topic: Looking for some more info on Altec 816A's
Posted By: AlfieDring
Subject: Looking for some more info on Altec 816A's
Date Posted: 13 December 2007 at 2:58pm
Im trying to find out if these are gonna be suitable for my needs.

Ive got hold of the plan and spec sheet from http://www.altecpro.com/products/vintage/index.htm

The intended use would be as the middle cab in a 3 way active setup, with scoop(s) beneath and a compression driver on a large horn above. System design goal is maximum electrical into acoustic conversion (efficiency of speakers, but also considering idle amp power as a reason not to go 4 way) to provide for live music outdoors to 200 people.

Quoted freq response is 50-1000Hz so this might be a tad on the low side for the comp driver?

Does anyone use them or have experience with em? If so what do you use on top? What x over points can you reccomend and what drivers do you load them with?

Ta :)

Alf



Replies:
Posted By: jbl_man
Date Posted: 13 December 2007 at 3:06pm

Yep,used to have a pair of the genuine Altec 816`s.with the 421-8h drivers(a slightly odd size at 16inches,due to a large frame!)...nice kick from around 100 up to around 800hz...very efficient...used a 2" driver above,crossed at 1k,no probs....i even used them as small bass cab from 60hz,to make a compact 2-way system...worked fine in a small hall...good throw as well....very loud for only 150w per channel...good"disco" sound!Wink

Edit....these also used to work well with the JBL"K" series driver,and the old Celestion powercell 250.....not sure about a modern driver..JBL E130 would be ideal,but its not around now.


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Be seeing you.


Posted By: AlfieDring
Date Posted: 13 December 2007 at 6:49pm
Cheers for the quick response JBL man :P And almost all good news too!

Im trying to compile a target spec now for the driver. Ive got the data for the JBL E130 that you suggested but cant find anything on that celestion one.

Looking over the drivers TS parameters (JBL E130, 421-8h and the altec 421-8LF) it looks like i need to find something roughly like......

Vas <300

Qts in range 0.19 – 0.25
Qes in range 0.2 – 0.3
Qms in range 1.8 – 3
Fs 30 – 40 Hz
Moving mass 60 – 80g


Closest match so far is Eminence gamma 15,  Qms is 5.13 though. Its a little high but then i noticed the spec sheet for the 816A also has a thing called the 515B in it with a huge Vas of 757L and Qms of 6.62.... Was this driver some kind of special option? It had a lot of xmax for a driver back then it seems...?

Ill keep nosing around to see what i can find.

Im also looking for any internal photo's as im having trouble figuring out the bracing!

Cheers

Alf



Posted By: boab
Date Posted: 13 December 2007 at 9:02pm
I have two working celestion powercell 15s in good condition.
Will be happy to sell them as they are not doing much just now.
Cheers
Boab
Edit: Just remembered I have one of those(copy) and 4 of the 12" versions. £150 the lot inc 2 x powercells.




Posted By: AlfieDring
Date Posted: 13 December 2007 at 11:10pm
Thanks for the offer boab, sounds like a pretty good deal. Ive no need of the 12's! Can i see some pic's of the 816A copy you've got? Particularly the insides if you'd be so kind :P

Also have you any info on the celestion's? Watt's yr of manufacture ect? Theres diddly squat on the net...

Cheers

Alf


Posted By: _djk_
Date Posted: 14 December 2007 at 3:03am
http://www.altecpro.com/pdfs/vintage/SpeakerAndMics/speakers/515-G%20series%20LF%20Speaker.pdf - http://www.altecpro.com/pdfs/vintage/SpeakerAndMics/speakers/515-G%20series%20LF%20Speaker.pdf
 
Best driver for the 816 cabinets, but very expensive, and not high power.
 
Look at the response graps (remember to add 1.7dB for 1M SPL), note that the horn loading drops off below about 160hz and it becomes a vented enclosure below there.
 
Also see the plans here:
 
http://www.lansingheritage.org/html/altec/plans/1970s-plans.htm - http://www.lansingheritage.org/html/altec/plans/1970s-plans.htm


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djk


Posted By: jbl_man
Date Posted: 14 December 2007 at 11:35am
Alfie,the 515b was Altec`s top-of the range cinema bass driver,also used in the A7 vott cabinet...i would forget about that,as they are quite low power,and almost impossible to find now.
The 816s i had were from the Altec factory,and had 421-8h drivers as standard.that being  basically a 150w extended-range guitar speaker,but they worked very well...as DJK says,the front horn loads it from about 150hz,below that it just works as reflex box.
Here is photo of mine from 1978!
Ian.


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Be seeing you.


Posted By: _djk_
Date Posted: 15 December 2007 at 3:19am
JBL E140 works quite well in these, will handle the power too.

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djk


Posted By: godathunder
Date Posted: 16 December 2007 at 12:54pm
I use a similar cab for kick bass. do very well from the high 40s. Ive never had any call to use them any higher than 200 but Id imagine theyd be good a couple of octaves higher. mine are loaded with k140s
 
 
http://img521.imageshack.us/img521/624/france013xj2.jpg -

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LOUDER THAN LOUD


Posted By: mykey
Date Posted: 16 December 2007 at 3:00pm
is that your system then Ger?

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......just all them hanging there like giant bananas.



Posted By: godathunder
Date Posted: 16 December 2007 at 4:57pm
2 of these at the front mykey - ancient but reliable jbl - parts of the old electrotec labq system- once in a while I even orientate the mids and his correctly. theres also some 15+1s, 12+1s and 8+1s depending on what Im using it for.
 
 
 


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LOUDER THAN LOUD


Posted By: jbl_man
Date Posted: 17 December 2007 at 9:22am
Great balencing act there Ger!..oh i love old skool stuff...are those pukka Court acoustics 18" horns at the bottom?
Ian.


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Be seeing you.


Posted By: godathunder
Date Posted: 17 December 2007 at 7:07pm

hi ian, all the cabs in the photo are part of electrotec audiolease's lab q system (stadium system from the 80s that we took something like 100 stacks of as part of a finance deal on a midas h3000). I didnt buy any of the hornloaded midhis, the mids and tops I have hung under the main system to cover the front rows. as far as Im aware the 18 ws are their own design but they could possibly have been a court oem jobbie. the 15s were part of the sidefill system.

aesthetically/structurally Ive always wanted another 15 per side but the tonal balance is pretty much spot on as it is.


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LOUDER THAN LOUD


Posted By: AlfieDring
Date Posted: 21 December 2007 at 11:01pm
Hello again, thanks all for the various inputs and pics. Ive worked up the plan from here (thanks DJK) ....

(large image)
http://www.lansingheritage.org/images/altec/plans/1970s-lf-plans/enclosures09.jpg - http://www.lansingheritage.org/images/altec/plans/1970's-lf-plans/enclosures09.jpg

.... in mm's but i cant work out whats going on with the braces behind the curved part? Either theres batterns up the side which dont seem very well placed combined with a part in the shape of an old telephone handset (have a look :P) Or theres a single battern behind the curve combined with a strange triangluar piece

Anyone got a photo of the insides or in a position to take one?

Ill put the plan up in mm's when its entirely complete.

Cheers :)

Alf


Posted By: boab
Date Posted: 21 December 2007 at 11:41pm
have you looked at this
http://www.wmeckle.com/ALTEC/Index.htm - http://www.wmeckle.com/ALTEC/Index.htm


Posted By: _djk_
Date Posted: 22 December 2007 at 11:52am
Pieces labled C and D are made from 2x4s or two layers of 3/4" laminated and are full height (16-1/8"). They are attached to either the baffle board or the sides (before the curved surfaces are mounted.
 
The best description and drawing of the 'ribs' is here:
 
http://www.lansingheritage.org/images/altec/plans/1968-enclosure/page09.jpg - http://www.lansingheritage.org/images/altec/plans/1968-enclosure/page09.jpg
 
They give the radius of the curve, but leave the exact fit to you. These are mounted after parts C and D, but before the curved surfaces. The glue blocks shown on the back of the curved surfaces are added after gluing in the curved surfaces. I would make the cabinets the same depth as the 825 plans, as they cut better from 4x8 sheets.
 
Because of the parallel top and bottom of the 816 there is some comb-filtering (dips) at 425hz, 850hz, etc. The 825 with its one top/bottom slanted (to be non-parallel) is a desireable mod to the 816, but more work (and adds 3-1/2" to the height of the box).


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djk



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