604 - 12 inch ?

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I think most Altec speakers using the 12" (414) use 2 with a small format HF driver.Just for that reason that they don't produce enough bass.Is this wrong ??? I just don't see the advantage of doing that with a 12" my thought would be to just use a real 604.I dunno

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While i can't say what the dual woofer reasoning is/was, i can tell you that in the case of 9844's the dual woofer setup has a very equivalent polar response to the 811 horn at the XO point, with good XO's it's a seamless match to my ears.

IMO, the advantage of a 12 inch duplex is mostly in it's compact size. Used as the sole driver in a full range system, you could be looking at a pretty small(under 2 cuft?) package.

I would also think that the smaller/lower mass cone would improve transient response, not sure if the difference would be audible, but certainly attractive to the number crunchers.

Of course i think most of us Altec fans/tinkerers/hobbyists picture a 12 inch duplex as the upper 2/3 of a 3-way system. My thinking is that you could have a very substantial "extended" range system in a package about the size of a 620 cabinet using the 411 woofer in the bottom.

Many years ago, Peavey made a single box system(project four) that used a 12 inch BW duplex, and a 15 inch BW to fill out the bottom. At that time, it was one of the most substantial drum monitor/side fill boxes i'd heard. Not exactly hifi, but the SPL and coherence were amazing for any loudspeaker, let alone one wearing a "Peavey" badge. I'd love to hear a refined version of that design approach using Altec components.

Just my .02.......................................

Thanks Guys for the explanations that helps.All good points and good reasons for doing the mod.:2thumbsup:

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Originally Posted by Altec Best

I'm still trying to figure what would be the advantage of doing that with a 12"..........

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It's all about getting the best blend between the woof/horn through the XO BW from a polar response POV, so for a nominally 15" driver this occurs in the 900-1200 Hz BW depending on the woofer's design and ~1300-1600 Hz for a 12" and why me and a very few others have been a 'broken record' about the 604 returning to a large enough horn/lower XO point as it was in its 'glory days' of the 601, 604B. From this we see that a 12" is the proper woofer size for the small horn/~1500 Hz XO that has dominated for most of the 604's career.

WRT to LF output, even the 604 needs a helper woofer to keep amplitude modulation distortion (AMD) below audibility at recording studio, piano bar SPLs if a low tuning is desired.

GM

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Originally Posted by Cal Weldon

From what I can dig up tonight, the original 601 was a 15" field coil.

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You are correct,sir!
However made the assumption he wasn't talking about that one since the discussion was about the 12.

I do need to be cautious however, as the conclusion you jump to may be your own.:D

Yes I tend toward the "inquiring minds want to know" side and until yesterday, I wasn't aware the original 601 was a field coil. So, while I'm not a "young guy" I am pleased to know I can still learn new things.

But you might come to a different conclusion. ;)

As our friend GM says: YMMV

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I wasn't aware the original 601 was a field coil.

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Did you know that most of those were in a stamped steel basket?

Sacre bleu! Say it's not true. Altec and stamped steel? My insides are hurting.

Cal, during the war years most of the Altec 15" baskets and all of the 12" (I think) were stamped steel, as all available aluminum was going into aircraft. Altec purchased these parts from Utah, who also produced drivers from the same parts during that period. Jim Lansing had begun his speaker business in Salt Lake City in the mid 1920s when Utah was still located there, so the business relationship may have been established then.

If anyone wants to learn more about the field coil Altec Lansing 601 and see some pictures, have a look at this thread:

Holy grail driver

BTW, the 601's horn was made much like the tar filled horns of the time only in miniature. Each cell was soldered together from sheet metal, with a beautiful brass throat casting. This horn is dimensionally similar to the 604 and 604B horn which followed soon after.

Cal, during the war years most of the Altec 15" baskets and all of the 12" (I think) were stamped steel, as all available aluminum was going into aircraft. Altec purchased these parts from Utah, who also produced drivers from the same parts during that period. Jim Lansing had begun his speaker business in Salt Lake City in the mid 1920s when Utah was still located there, so the business relationship may have been established then.

If anyone wants to learn more about the field coil Altec Lansing 601 and see some pictures, have a look at this thread:

Holy grail driver

BTW, the 601's horn was made much like the tar filled horns of the time only in miniature. Each cell was soldered together from sheet metal, with a beautiful brass throat casting. This horn is dimensionally similar to the 604 and 604B horn which followed soon after.

anyway - I'm wondering to purchase this odd 12" driver, also because it's quite close to my location. unfortunately the seller didn't reply until now. there is also no asking price mentioned - any suggestions about its value? - even if it is a 'hot rod'?
best,