[mariolmb]

Sorry for the word "afraid."..

Thanks for the answer.

If your satisfy, it's all good for me.

But 15 DB of loss starting at 7.5k is not standard for an Altec HF driver.

But your choice to get :

"smoothest Altec speaker you will ever encounter within its range"

give the reason for your choice to get this curve and this range.

Thanks

Mario

[S Clark]

Mario, it's about +- 3 db until around 12000 hz.  Before that it stays really flat through the heart of the music- about +- 1.5 dB.  Perhaps the driver isn't delivering what it's supposed to, but it's not because of the voice coil. 
As far as the "choice", the crossover is not causing the drop off above 10K Hz, but instead corrects issues at  1700 Hz and creates a smooth transition around 1200 Hz from woofer to tweeter.  There were also several issues that were caused by ringing with the horn, that were smoothed considerably as we experimented with foam. 
The key areas of improvement were solving issues of harshness with brass instrument that were really showing up in the low treble and upper midrange. Also, there was an overall increase in detail and clarity by creating an open baffle for the bass.  But a crossover can't create a response where one doesn't exist.  I'd love to see some graphs of  811 horns that you've worked with, especially those that had extended responses.

[mariolmb]

 "it's about +- 3 db until around 12000 hz.  Before that it stays really flat through the heart of the music- about +- 1.5 dB."
That's lot better then I can do, as I tried to keep my cross over as simple as I can... normally less then 7 components.


...This pictrure is a standard compression in an 811b horn, Mics -15dBFS 6 feets front 48" high, no cross over, just a plain driver.


Me I am more like that on an A7 (825/828 style) cabinet with a cross over described with the picture.


This pictrure another compression in an 511b horn, Mics  -15dBFS 6 feets front 48" high, smooted a 1/6, cross over HIRAGA style ((7parts) cut at 500, measured in my men cave, valve amplified single end, just a plain  A-7 500


This pictrure is 806a compression in an 811b horn, Mics -15dBFS 6 feets front 48" high smooted a 1/48 , cross over HIRAGA style ((7parts) cut at 800, measured in my men cave, valve amplified single end, just a plain  A-7 800 for me.
It's not Altec Hifi style box, but lot's of guy who listen music with single end amplifier like those for speed and vivacity of the music. Lot better for the first octave with with an amplified sub 18 inch  crossed at 50/80 upon of the room ( Not in those measurement).

But my point was not about your final example of your Valencia, the one you described in last post.
it was about the loose of 15db from 7000hz(103db) to 18000hz(88db) without any recovery in the picture I put with my post.
It's not a kind of picture I'm familiar with on an HF Altec driver and was the reason I decided to say to other interested DIYer that's not an standard result.

The reason was not to critic the choice, but to encourage other to do their own research, they will appreciate what HF Altec driver will give to them for working with.
Lots of result could be done with a cross over on any Altec HF driver. Because rare are the speaker that can give you that amount of octave to work with... and the dynamic, and.. the speed... and ... etc... etc...


To add a point for comparaison I add a picture from a pair of Magneplanar 3.7i with a Pierre Lurne amplifier, just to show what an A7 is capable of with an valve amplifier single end of 8 watts in a man cave without any gadget.




But my measurement  was with an altec that give  99-102 db of pressure an an Magneplanar that give 83-86 db of pressure.
Was an A7 as refine as the maggies...no. Was the maggies have nicer dynamics...no  Wich one I prefer to listen music... both
But for lot's of pressure level musics, say average level at 95 DB+, Altec eat the Maggies
Hope it is enough measurement for today.  LOL

Mario

[S Clark]

Thanks for the graphs. Indeed it does look like there is an issue with my compression driver compared to your measurements.   I have several voice coils, including a repaired original that I may try out- if I ever get around to it.  If I do, I'll take measurements and post them.  I would guess that the voice coil is the most likely suspect, although I think I'll call Bill at Great Plains Audio and ask if he has any ideas. He probably knows more about Altec speakers than anyone else in the U.S. 
I appreciate your helpful reply.
Scott

[mariolmb]

Scott,

Hello,
I never see it, but if your broken original are 20275, in you 807 don't play to try to fix it.
Go to an experienced repairmen to fix it.
Aluminium diapragm have the reputation to go higher then other one.

But you will have a choice to do whatever is the best in your environment.

Go for the 802 with an 34852 if need more power or if you can't find what you want with you 807, but lot harder to tame the med bellow 4000, you needs lots of parts,
normally if you add...
more problems.

Sorry if I  can't help you, as I have not real experience with 807 and his 34726 symbiotics diapragm o 34647 replacement in an 1600 to 1800 cut off
Me my work is confined to do it at a 500 or 800 cross over an little hair cut from 5/800 to 8000
But I am sure you can do it to  go 14000 an may be to 18200 upon of your set up.
If great plain audio recommended this diapagm to you, it is the one you need.
But you could have lot's of other issues too, then the diapragm.
You really need to know that me, my 511 and 811 that I work with, are tamed with plumbing clay at the external, and for the 511 only, I add a autoglued mat behind the front wall, nothing inside in  front of the driver,(no foam as per all A7/A5 cab. )  this way I got no ringing at all.
Altec are like musical instrument, you need to tune it to your tast. May be you can try both way to see if "improvement were solving issues of harshness with brass instrument" are still in control with one and the other, and then you'll know  wich you prefer with or without the foam.
Valencia is an 95db speaker, so the Woofer is tamed to this level, so it give you lot's space to work with your HF driver.
But at one point, what you will get in leveling the HF, you will loose in speed and voicing of the lower. and then you need to finish with an Lpad fix or variable to keep your dynamics,  your choice.
It's a compomise, not so easy to get, but very  rewarding when you will get it.
You can read to end of world, but one thing is sure, when you will reach what you work for... you will know, your ear will tell you.
What Danny have to say about it? He have experience, I'll surely had a couple tricks to help you.

N.B: Even if it's not my first choice, you can keep what you got, as it look super to 10K, and add an Super HF JBL, easy to do after 10000hz, but again not my cup of tea, as this tweeter in top of the box... berk ... LOL

Ciao

Mario

[mariolmb]

sorry....

The "autoglued mat" ,

they call it  : Dynamat

This I put it around the horn inside the wall, not a the back of the wall itself.

Buy it here at Solen Electronics.in sheet of 1 meter to 1 meter

[jimjulian]

Hello,

   I have a set of Valencias with drivers that have broken leads. I've been giving some thought to your repair. It's August 2019, How are they holding up?
Did the modification effect the frequency response?

Thanks,
Jim J.

[jimjulian]

For these types of repairs on fine stranded voice coils I have used silver conductive epoxy with great success.  No heat/soldering needed to risk causing more damage.

Did you glue the broken leads or replace the leads? I have a couple of 806-8s with three toal broken leads. I also have a small packet of silver conductiive epoxy I'm ging to use to patch them up with. I think repacement may be better since age has effected the tensile strength of the leads. If they break once there's a greater likelihood they'll break again. The metal is fatigued after 20-30 years of vibration. A well chosen replacement would last again as long.

[S Clark]

I was able to CAREFULLY solder a thin wire to mine, although I replaced them anyway.  I picked up a pair of new voice coils from Great Plains Audio.  They have the original Altec equipment for their manufacture. 

[f575m]

Hello Scott,

I have read your posts, they are very interesting. I have a chance to purchase a mint, one owner, pair of 846A Valencias but the crossover cut at 800Hz bothers me. I have a question for you, did you take the xovers to Danny for upgrades and, if so, how did you like them?

Cheers,

Horacio

[S Clark]

Horacio,
I took the entire speaker to Danny.  We quickly abandoned the original crossover and built a new one. He also determined that the porting of the Valencia A was providing so little load on the woofer, that we went with an open baffle instead.   This increases clarity in the midrange.  The low bass of the Valencia was already a weak point (surprisingly for such a large woofer), so it plays best with a sub. 
At this point I am quite happy with them.  They are especially good at vocals. 
Regards,
Scott

[idler]

Scott,
Any more details about the new crossover?  Also interesting was your comment about running open baffle.

Idler