"Crossover Design for New Project"

[Earl K]

So I'm trying to decide what to do with drivers 1&2 and 5&6 drivers 3&4 are the good ones(NOS) but we were trying to match them.Which left the best woof out of the equation which I didn't want to do.

- Have woofers 1,2,5 & 6 ever been remagged ?

- If not , send a pair into GPA for recharging , & then retest upon return to see if their motor strength improves up to the levels of 3 & 4 .

- Alternately, dump the alnicos & buy ferrite 416(s) . Their motors don't weaken with normal usage .

<> cheers

[Altec Best]

[quote]

- Have woofers 1,2,5 & 6 ever been remagged ?

If I had to wager, I would say "NO"

- If not , send a pair into GPA for recharging , & then retest upon return to see if their motor strength improves up to the levels of 3 & 4 .

This is what I was thinking,I have them boxed already.

- Alternately, dump the alnico's & buy ferrite 416(s) . Their motors don't weaken with normal usage .

I like the Alnico's.Am I hearing a difference between them (Who knows) but when I had done testing (listening Blind) awhile back I always tended to pick the Alnico drivers,coincidence could be, but I feel I was hearing something I preferred.

The most telling difference between Alnico and Ferrite test for me was between a 604-8K and a 604-8H.I clearly liked the 8H way better.And was the easiest test for me to tell apart.With the woofers probably not so easy to tell the difference though.They (Ferrite's) cost way less too.But all the drivers I have for this project are Alnico V and would like to keep them all the same.

PS. So Earl are you saying that a vertical placement would be better ? We came up with the horizontal placement as it would allow me to keep the woofers up at the top of cabinet in close proximity to the 511E which is important(Single Point Source).With the port closer to the floor.When I first started that is how I had them configured Over/Under but was discussed that a horizontal placement would be a better configuration.Bfish first suggested the Horizontal placement, I think it would have a better polar response he said, I think. Regards !

[Earl K]

So Earl are you saying that a vertical placement would be better ?

No, I'm saying that even under less than ideal circumstances, vertical arrangements can also be made to work ( with a smattering of room treatment ) .

I went vertical, because I run an MTM setup that creates a nice "virtual point-source" image ( think large 604 , but with bigger everything ) .

However, I think horizontal is your best bet .

A design nod towards the beautiful Danish stylings of the Laguna, would be the direction I would test out .



JBL went this route ( eventually ) for their current TOTL speaker .



- Uncanny, isn't it ?


<> cheers

[Altec Best]

[quote=Earl K;1838838]

However, I think horizontal is your best bet .

OK phew !! Had me nervous for a minute.I should have the room gain measurements posted tonight or early tomorrow.

A design nod towards the beautiful Danish stylings of the Laguna, would be the direction I would test out .

Yes the Laguna and 820 are 2 of my favorite looking Altec Cabinets.Altec had this design in the early 60's which I think is a great design.Pano calculated volume of my cabinets at 22 cu ft.Which is a behemoth.I've been debating cutting down the height a bit.19-20 ft. GM said that would be OK but not much more than that.If I still wanted the f's I was looking for. Thanks Earl !!! :thankU: Regards ~ John

[Altec Best]

Hey GM,

Here are those room gain measurements you asked for.I took a few in each place (inside-outside) inside was 1meter,center of room,sitting position. First picture is inside and the second is out Thanks !!

1/3 Octave smoothed.

[Earl K]

- Have woofers 1,2,5 & 6 ever been remagged ?
- If not , send a pair into GPA for recharging , & then retest upon return to see if their motor strength improves up to the levels of 3 & 4 .

This is what I was thinking,I have them boxed already.

BTW, have you checked the polarity of those 4 drivers to make sure the cones move in the correct direction ( when pulsed with a 9V battery ) ?

- If they're moving the wrong way at this point / then due to last springs info ( ie; "Panos Plight" ), odds are that your woofers have been previously remagged by a machine using the wrong polarity .
- If that's the case, remagging with the correct polarity isn't likely going to restore them to 100% ( again,, according to "Panos Plight" ) .



Since you have (4) 288C drivers, why not put diaphragm #2 into either driver #3 or #4, to see if you can improve its' HF response to match driver #1 ?

<> cheers

[Altec Best]

[quote]

BTW, have you checked the polarity of those 4 drivers to make sure the cones move in the correct direction

No I haven't but I will.I'll let you know my findings.

Since you have (4) 288C drivers, why not put diaphragm #2 into either driver #3 or #4, to see if you can improve its' HF response to match driver #1 ?

They are completely different diaphrams,drivers 3 & 4 are 299-8A's w/diaphrams 25884.I haven't measured them yet though and think it would be a good idea to see how they measure on the 511E's.But the 288's w/23763 diaphrams sound real nice on the 511E for the short time I listened to them.They were real nice sounding.

I'm going to remeasure the 416's too.As the measurements don't seem right for the condition they are in.But looks can be deceiving as we all know.I'm going to do the Vas measurement differently as well.It will be good to see if I'm getting consistent results for one.And hoping for much closer to spec results for another.But even as they are, GM and Pano think I will still have an Above Average Sounding System due to high efficiency of the system.And with the size of the boxes plus the corner loading I should still be getting some great Low Bass response. Thanks Earl !

[Earl K]

They are completely different diaghrams,drivers 3 & 4 are 299-8A's w/diaghrams 25584.I haven't measured them yet though and think it would be a good idea to see how they measure on the 511E's.But the 288's w/23763 diaghrams sound real nice on the 511E for the short time I listened to them.They were real nice sounding.

- ( 3 & 4 ), Huh ?

- Obviously, your understanding of this is somewhat muddled .

- These are your drivers according to an earlier post by you .


- FWIW, once you put a 23763 diaphragm into any one of those 4 drivers it becomes the functional equivalent of the 288-8E driver .

& BTW, these older ( pre "G" ) magnetic assemblies just don't have the magnetic juice to be called the equivalent of a boan fide 299 / no matter which diaphragm you stick into them .

So,,,, swap in that 23763 diaphragm ! ( or are you just not comfortable doing that ? )

- If not, have Pano work on it .

<> cheers

[Altec Best]

[quote]

- ( 3 & 4 ), Huh ?

- Obviously, your understanding of this is somewhat muddled .

- These are your drivers according to an earlier post by you .

Earl Yes I know !! They are all 288C drivers I am just describing them that way just to distinguish them between drivers 1&2 and drivers 3&4 for reference only.The G,H,etc.. also had 30 Lb mags were as the C are 20-22 or thereabouts.

Drivers 1&2 were converted from 24 ohm's to 8 ohms with a 23763 diaphram
Drivers 3&4 were converted from 24 ohm's to 8 ohms with a 25884 diaphram

That's it, they are still 288C drivers.If I didn't people would assume they were all the same "Would They Not". Drivers are all the same just different Frams.

For our purposes we'll just call them 288-8E's

[Panomaniac]

- If not, have Pano work on it

Which reminds me. I forgot to send you the centering shim. All packed away now while the room is under renovations. Gotta to see if I can find the spare.