Altec 409's

[dbale]

Cheaper by the dozen. As I recall, Altec packaged 409's 12 in a box. I used them as car speakers, along with 405's, before the "Voice Of The Highway" gear was launched.

If you ordered 240 you got a 10% discount off cont. net in 1980.

My first Altecs were 409s that I installed in my first car.

I don't think they are even close to published sensitivity.

[gortnipper]

Looking for cabinet suggestions now, if you please.....

Cheers all

Todd recommended a 3 cu. ft. vented box - http://www.hostboard.com/forums/f700...-speakers.html

[Alien_Shore]

After a listen to Gortnipper's wonderful GPA 604's recently, I decided to take some baby steps and bought some Altec 409 drivers

Coelacanth - very interesting nick name you chose there.
I was recently at a conference where Richard Pyle gave the keynote address about his dive for NatGeo to find the Coelacanth. Very interesting! Older than dinosaurs LoL!

[Coelacanth]

Thanks for the info guys. I should probably be a bit more circumspect about how I describe things.. these 409s wont win any competitions, I am under no illusion there. I guess what I should have said is that there is a certain magic that seems to happen when occasionally you connect a cheapish driver with little or no crossover network to the business end of an amplifier with tooobs inside..

Interestingly these units have gotten brighter and brighter since I connected them.. to the point of serious overbalance. Further suggestion that the caps have gone bad, my guess.

Anyhow, I wasn't really looking for forever speakers in the 409's, it was more of a psychological ploy on my part to convince me that Altec is the way forward for my forever speaker project.... which I am happy to announce will be... Altec model 19 clones with GPA drivers and Zilch XO's...

It has taken me some time to decide between a 604 based project and the 19 clones but I think I have made the right choice and am looking forward to getting under way.

Mike, thanks for noticing the Coelacanth thing. I was fascinated by the story of its rediscovery - a living fossil. As a kid, I thought it was pronounced "coal a kanth". When I heard it pronounced properly - "seelakanth" - the odd things the word does in the mouth really appealed to me. I don't know what the correct term is for what I am describing but for all its unusuall consonant placement, it still ends up a nice word to say.. if you catch my drift. Sorry for going OT.. :-)

[gortnipper]

which I am happy to announce will be... Altec model 19 clones with GPA drivers and Zilch XO's...

Excellent. Did you score those horns off of Peter?

[GM]

My only criticism is slightly pinched or set back vocals........

Looking for cabinet suggestions now

These are designed for a 70 V line app, so typically ?project? vocals to the point of ?shout? if not coupled with an appropriate auto-former to one, so something?s amiss. Hooked up this way, its published response is 50-15 kHz +/- 1 dB, which considering our hearing acuity is to say ?dead flat?.

It could be the caps and/or one tweeter and/or one woofer not working properly.

Cab wise, its specs are typical of drivers designed for a fiberglass damped ?leaky? basket, so with a T/S max flat alignment coming in at a hefty ~51 ft^3 net/24 Hz Fb, either an OB, IB, or TL are the best options with the latter in an offset driver tower form being the most floor space efficient.

A generic TL design routine I?ve historically used for this type driver [ultra high Qts] calcs a ~53? H x ~130? WxD with the driver down ~20? [all dims i.d.], damp to ?taste?.

It should closely match its IB response except in a smaller net bulk and with a ~2x higher excursion limited power rating due to the amount of damping required to quell its inherent high Q ?ringing?; which will also damp down its Fs impedance somewhat, so will present an easier, more efficient load if using a high output impedance.

Spaced up off the floor to get the driver up to the average seated ear height and placed near/at a wall, it should perform well enough for most music at a modest SPL, though of course they should ideally be high passed and let a ?sub? system handle the < 80 Hz BW.

GM

[Coelacanth]

Excellent. Did you score those horns off of Peter?

No - either he sold them or what you saw were JBL's of some flavour according to Peter.. nevertheless I am undeterred and will just have to look at importing some along with the rest of the gear. I will likely start a thread here as I get under way... I will have some questions no doubt...

- - - Updated - - -

These are designed for a 70 V line app, so typically ‘project’ vocals to the point of ‘shout’ if not coupled with an appropriate auto-former to one, so something’s amiss. Hooked up this way, its published response is 50-15 kHz +/- 1 dB, which considering our hearing acuity is to say ‘dead flat’.

It could be the caps and/or one tweeter and/or one woofer not working properly.

Cab wise, its specs are typical of drivers designed for a fiberglass damped ‘leaky’ basket, so with a T/S max flat alignment coming in at a hefty ~51 ft^3 net/24 Hz Fb, either an OB, IB, or TL are the best options with the latter in an offset driver tower form being the most floor space efficient.

A generic TL design routine I’ve historically used for this type driver [ultra high Qts] calcs a ~53” H x ~130” WxD with the driver down ~20” [all dims i.d.], damp to ‘taste’.

It should closely match its IB response except in a smaller net bulk and with a ~2x higher excursion limited power rating due to the amount of damping required to quell its inherent high Q ‘ringing’; which will also damp down its Fs impedance somewhat, so will present an easier, more efficient load if using a high output impedance.

Spaced up off the floor to get the driver up to the average seated ear height and placed near/at a wall, it should perform well enough for most music at a modest SPL, though of course they should ideally be high passed and let a ‘sub’ system handle the < 80 Hz BW.

GM

Many thanks GM.. will add this to the maelstrom in my head :-)

[SD-50]

Being following this thread and earlier today on a whim checked the local Craig's list and snapped these up this evening. Any suggestion for cap value?

[Alien_Shore]

According to the 409B spec sheet, the coax crosses over at 2kHz. Given that, I'd start with a 7 uF cap for the 1st order high pass.