New Project Idea - LE10H-1's with Altec 806 Horns

[Zekeman]

I am thinking about blending LE10H's with a set of Altec 806 drivers I have. I also have a set of N96 networks and cabinets from L96's.

My questions are:

1. What would be the best horn to mate with the 806's? I have 811's but they are too big. Ideally I'd like to use a cabinet like the L96's but I will probably end up building new, similarly-sized cabinets.

2. Could I modify the N96 networks and use them in the new setup (I like the idea because the N96 networks already have attenuator pots and an existing circuit board) also I know nothing about crossovers.

Thanks!

[macaroonie]

LE10 is a great starting point and the 806 will do pretty much what a 2425 / 2426 will albeit not as great a power handling. Why not think in terms of a slim tall floor stander approx 12" wide 36" - 40" tall. See if there is a waveguide that fits within those sizes , there is one approx 12" square that will allow the Altec to mount. Sorry I cant retrieve the part no.
Maybe leave space for a slot tweet , or even some of those ribbon tweets that are out there are well good ( Aurum Cantus )
Now here is the tough bit , the N96 is not ideal for this as it stands in that the crossover frequencies are not really going to allow the altec to shine. Other thing is there is not the correct padding to match the sensitivity of the horn down to the system sensitivity. This is fairly easy to fix.
Why not have a ( long ) read at Zilch's epic ' quick and dirty 2 way ' thread. In that he touches on more or less what you have at hand.
The crossover gurus will lend a hand when the time comes. I have long held notions about using the LE10 H-1 with a horn , it is a very responsive driver and should mate very well . Good luck

Here is the link into the Zilch experience

http://www.audioheritage.org/vbulletin/showthread.php?9745-Quick-amp-Dirty-4430-Inspired-Two-Ways-Part-I&p=44254

[Earl K]

Marrying an older Altec or JBL aluminum diaphragmed driver with any le10 variant is ( IME ) indeed a worthy endeavor .

One might create (a vintage component based ) Array 1000 ( once some sort of tweeter is added & if one could achieve some good imaging from whatever horn is chosen ) .

Unfortunately, the N-96 idea won't work well at all ( unless it's so completely rebuilt as to be unrecognizable - ie; no $$ savings ) .

It's best to start with a blank piece of paper for a design .

- As shown by Zilch here , the 806 needs @ 15 db of HF compensation (ie; midband padding ) to become reasonably flat for HiFi duty ( ie; reaching 20K ).

- The relative impedances between the woofer & the compression driver will dictate whether or not the 806 can be made flat enough ( before its' output level becomes too low, relative to the output/sensitivity of the le10 ) .

- FWIW, Zekeman should post the DCRs ( dc resistance ) for his 806(s) . They might be too high to work with the le10h .


http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=23763&stc=1&d=1174451089

- A design philosophy worth mimicking ( for a new network ) is the network for the AM6212 (http://www.jblproservice.com/pdf/AE%20Series/AM6212,00-WH.pdf) .
- Its' salient features are ;

(i) No Variable Lpads ( Midrange padding is accomplished by choosing an appropriate capacitor size ) .
(ii) No "Fixed Lpad" ( same as above ) .
(iii) Smallish coil size ( in the Hi-Pass section ) , steers lower frequencies down-wards after an LCR ( notch filter ) filters ( carves ) out the last remaining midrange hump ( typically found in the 2 - 3K region ) .
(iv) LCRs ( series type ) notch filters are used extensively to flatten out response anomalies.
- They are all placed after the standard LC parts of the network ( essentially ,they are strapped across a drivers input terminals ) .

As an example ( of this design philosophy at work ) here's something I cobbled together & tested out when I saw this thread ( earlier ) .
- The pieced together HP portion ( of a full network ) has @ 12 db of midband padding ( as measured at @ 2800 hz ).
- If put into practice ( with a beatup 2410 ), some may want to add a tweeter of sorts for above 12K ( as JBL sometimes does ) .

http://www.audioheritage.org/photopost/data//500/jbl_2410_on_waveguide_with_filtering3.png






Horn ???

http://www.loudspeakersplus.com/PDGImages/XT120.jpg (http://www.loudspeakersplus.com/product/XT120/18-SOUNDXT120/)

- I'd be inclined to see if I could get the XT120 to work ( it's an elliptical waveguide made by 18 Sound and is bolt-on like all these old drivers ) .
- It looks to need a highish crossover point , like @ 2K .

<> cheers

[Altec Best]

I am thinking about blending LE10H's with a set of Altec 806 drivers I have.

Is selling the 806's an option,or just picking up a pair of 802-8G's or a pair of 902-8A,B,s feesible.IMO it would make your project a whole lot easier WRT the X-over.As they extend much higher than an 806 and would be less likely to need a tweeter period.And you would need to do less X-over work.

The 806 is an old driver that didn't extend high enough IMHO 13Khz at best.And was phased out after the 806-8A,the 802G/902's were developed due to their (806's) inferior HF response.With the advent of the tangerine and larger magnet's in the (802's) the 806 is obsolete.It was a great driver in the 1960's . I know it may cost a little more money but the bottom line is we want them to sound good. Best Wishes with your project !! ;)

[macaroonie]

This little horn might fit the bill , should play down to 1200 without issues.

http://www.p-audio.co.uk/pdf/PH-220.pdf

Cheap too :)

[Zekeman]

The DC resistance measured on the 806's is 8.5 in one and 9.2 in the other.

[Earl K]

- FWIW, Zekeman should post the DCRs ( dc resistance ) for his 806(s) . They might be too high to work with the le10h .

The DC resistance measured on the 806's is 8.5 in one and 9.2 in the other.

Thanks !

If one designates the le10H as a 7 ohm woofer ( from its' lowish dcr figure ),,, &

If one designates the 806 as an 11 ohm driver ,,, then

One will see ( after some math ) that when playing together the 806 will "pull" about 4 db less juice from the amp ( due to the 806s' higher impedance ) .

The @ sensitivety of the 806 is 104 db ( 1 watt / 1 meter ) and the le10H is @ 90 db .

That 14 db difference becomes just 10db when this impedance differential is accounted for .

Applying just 10 or 11 db of midrange-specific padding ( on the 806 ) will still leave the 806 rolling off its' HF, at around 10K .

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=23763&stc=1&d=1174451089

So,,, matching up an older ( high impedance ) 806 with the le10H would still necessitate the addition of a tweeter above @ 10K .

Conclusion,,, I don't see the point to pursuing this project ( when using the high impedance 806a ) . Sorry ! :(

<> cheers

[Zekeman]

OK....so back to the drawing board to re-think the project. I am thinking I probably scrap the 806's for another driver. What drivers would be optimal?

[Earl K]

OK....so back to the drawing board to re-think the project. I am thinking I probably scrap the 806's for another driver. What drivers would be optimal?

If you want to use an aluminum diaphragmed compression driver / then buy a new pair of GPA 902-8As ( @ 205.00 ea ) .

GPAs 902s ( 9-Slit Radial Phase Plug ) has always get top marks in the subjective comments department ( from what I read online / though I don't own any ) .

Here's the FR of a pair ( as measured recently by Zilch on a 511a ) .
http://www.audioheritage.org/photopost/data//500/GPA_902-8A_511A.PNG
Here's another ( posted by iain42 a while back & doctored up by me ) .
- His measurements ( though with a different EQ ) nicely support Zilches measurements .

http://www.audioheritage.org/photopost/data//500/GPA_902-8_on_511b_5.png

Here's an older measurement ( by Zilch of course ) of an original Altec 902 using the 11 Slit Radial Phase Plug .
- It drops off pretty fast after 13K ( with that particular diaphragm )

One can see that GPAs newer phase plug has bumped up the top end nicely out to 20K ( plus is arguably flatter in the 5 - 10K region ) .

http://www.audioheritage.org/photopost/data//500/902_M14_on511A_D34647.PNG

If you buy a pair of these GPA units and sign onto the Ewave thread over at AK / you might expect a bit of help with a custom crossover design ( once Zilch gathers up some interest in it as a project ;) ) .

Alternately, buying a pair of B&C DE250(s) ( it has a mylar diaphragm ) will get you some immediate help at AK ( as long as you choose a currently approved Ewave waveguide ) .

<> cheers

[timc]

I have just measured the DE-250 on an Eminence 290 horn. Here are the results. Horisontal first, and vertical at the bottom

[macaroonie]

Are there no aftermarket Dias that fit the 806 motor , poss with Ti ? Radian ? :dont-know: In any case what would be so terrible about the classic solution and top out from 8-10 KHz with a slot tweet ?

Just asking , Mac