Altec 605A?

[Figge]

what´s the diffrence between altec lansing 605A and 604?

[Mr. Widget]

That has been discussed here, but I don't remember the details. Try a search. As I recall the gist was that the 605 is a poor little brother to the 604.

Widget

[tomp787]

Hello,

The Altec 604 and 605 differ in the magnets used for the LF and HF drivers. An analogy would be the 604 uses the 515 magnet structure while the 605 uses the 416 magnet structure. Similarly the 604 uses the 802 magnet while the 605 uses the 804 or 806? magnet. Sorry but I've forgotten my altec HF model numbers.

So while the 604 has greater efficency the 605 may have better low frequency response in home use. The 605's smaller magnets also result in a smaller time delay between LF and HF.

I think you can build a good system with 604 or 605. I don't believe one is bad as stated above.

I have more 604/605 info if you need it.

Regards,
Tom

[speakerdave]

Originally posted by tomp787
So while the 604 has greater efficency the 605 may have better low frequency response in home use.

Originally posted by tomp787
The 605's smaller magnets also result in a smaller time delay between LF and HF.

Hi,
I don't think I understand either of these statements. Could you explain?

Thanks,
David

[tomp787]

Hello,

The 605 has a smaller magnet and higher Qt than the 604 so it has more low frequency output. This should work better in a home style cabinet. The 604 was often used in a big baffle which better suited its lower Qt.

The 604/605 are built with the tweeter stuck on the back of the woofer. So the woofer and tweeter diaphragm are pretty far apart: 5.375 inches for the 604 and 4.25 inches for the 605. If you want to time align the woofer and tweeter this has to be done electrically. The 605 can use a simpler network to do this if you want to do it passively.

Did this explanation help?

Regards, Tom

[speakerdave]

A little--the part about the different physical sizes of the magnets. If you don't mind--What is Qt, how does a smaller magnet make it higher, and how do either or both of those make more low frequency output? It's just that as a non-technical person I see these terms used a lot and begin to think I understand what people mean by them, and then someone says something that just doesn't make any sense to me.

Thanks,
David

Edit: For example: The JBL 124/2203 and the 122A have very different size magnets, but they seem to be able to work in the same frequency ranges in similar-sized cabinets.

[tomp787]

Hello again,

The Q refers to the damping of a system: a q of .5 is called critically damped which means it has no ringing or overshoot. Q less than .5 would be overdamped, greater than .5 underdamped. A stronger magnet will have more control over the cone so will likely have more damping (lower Q).

Your mention of the 122A and the 124 is a good comparison to the 604 and 605. To me the 604 is to the 605 as the 124 is to the 122A. I find them more similar than different as I think you do, but Mr Widget posted that the 605 was clearly inferior to the 604. That was the primary point of my first post, that they are different, but that one might choose one or the other depending on the goals of your system.

Please PM me if I my explanations are still lacking.

Regards, Tom

[Mr. Widget]

Originally posted by tomp787
Mr Widget posted that the 605 was clearly inferior to the 604. That was the primary point of my first post, that they are different, but that one might choose one or the other depending on the goals of your system.

Actually what I was saying was that as I recalled the 605 had been discussed on an earlier thread and the 605 did not meet with rave reviews. I personally have no experience or opinion on the 605.

I do have experience with the 604E and well... let's just say if I found a pair today they would be going the eBay way.

Widget

[speakerdave]

Originally posted by Mr. Widget
I do have experience with the 604E and well... let's just say if I found a pair today they would be going the eBay way.

And make somebody's day!

Tom--Your response to the initial question has caused me to examine how much I really understand about this subject. So, I'm testing my ideas. Another example: The JBL 2225H has a Qt of .28, the 2235 a Qt of .25. They use the same magnet structure. Yet I think everyone would agree these are completely different bass drivers, that the 2225 is much more efficient, and that in an enclosure of a given size the 2235 would have more extended bass response. Obviously there is a lot more that goes into Qt than magnet strength and a lot more that goes into bass response than Qt.

Assuming that the cone, moving mass, voice coil and suspension in the 605 and 604 woofers are the same--that is, all other things being equal--the smaller magnet in the 605 would tend to tilt the reponse down at the top and up at the bottom, neither being necessarily improvements in the sound. In fact the 605 is crossed over at 1500 and the 604E at 1600. Adding the box to the electrical and mechanical characteristics of the driver as a third set of factors in the total system, isn't it true that either driver could be brought to the same final state of tune (Q)? And I think cabinet size would be more critical for the 605. The apparent increase of low frequency output is 1) relative to midrange response, which moves down, and is 2) largely overhang. With a smaller magnet and the same moving mass and suspension the 605 would be LESS able to work in a smaller box. Overall response would be at least 3-5dB less.

If any of this is wrong, I would admire to be corrected.

David

[4313B]

Originally posted by speakerdave
Edit: For example: The JBL 124/2203 and the 122A have very different size magnets, but they seem to be able to work in the same frequency ranges in similar-sized cabinets.

Different animals. The 124/2203 is literally a shrunken 136/2231 and usually exhibits a "shelved" response depending on volume/tuning. It was designed to offer the same bandwidth as the 136/2231 in a much smaller package. The 122 often has it "beat" in LF response due to it's much weaker motor (again, depending on volume/tuning). "The 124 has way too much motor". Several pluses for the 124 are that it obviously exhibits less dynamic compression and its transient character is fantastic. Wayne Parham had a Pi config for it years ago and it can make for a brutal sub driver down to ~ 30 Hz.

[Don McRitchie]

I've never heard a 605 to compare it to the 604/E/G/K of which I am familiar. However, I do know that there was a severe market backlash to Altec from the studio industry when it was introduced as the replacement for the 604C. In around 1962, Altec went on a cost cutting exercise that saw the introduction of the 605 and 806. Where the 604 could roughly be described as a 515 bass driver with a 802 coaxially mounted, the 605 was roughly a 416 with an 806. However, instead of selling this speaker as a lower cost altenative to the 604, Altec marketed it as a "new and improved" design to supercede the 604. Thus it was given the 605 moniker and the 604 went out of production.

This single act, more than any other, opened the door for JBL to compete in the professional market against Altec Lansing. Studios balked at this product, considering it noticably inferior to the 604. In particular, Capitol, a long time Altec customer, turned to JBL to supply studio monitors. They were impressed enough that they later standarized on JBL monitors for all of their studios. Soon JBL was supplying monitors to the industry at large. Eventually, Altec realized the error of their ways and re-introduced the 604 as the 604E SuperDuplex (the 605 had been given the longstanding Duplex brand name). However, by then it was too late. The genie was out of the bottle and JBL would come to dominate the studio market in subsequent years.

In summary, the 605A was not an intrinsically bad speaker. It was Altec's marketing blunder that, more than anything, gave it a bad reputation. Nonetheless, it was considered to be significantly different in sound from the 604 that it replaced.

[ERICTOURNERET]

I Have A Paire Of Karlson Enclosure With The Altec 605a
(16 Ohms). My Amplifier Is An Artec 70 (8 Ohms). I Have Added A Paire Of Altec 15067 Transformer To Convert The 8 Ohms To 16 Ohms. The Sound Is Fantastic !
If You Have Altec Loudspeakers 16 Ohms And 8 Ohms Amplifier Don't Hesitate To Use The 15067 Transformer. The Sound Is Totaly Different And More Dynamic.
Regards
Eric

[Meshplate]

I've never heard a 605 to compare it to the 604/E/G/K of which I am familiar.

Don't need to add any more to that: bench racing.

However, I do know that there was a severe market backlash to Altec from the studio industry when it was introduced as the replacement for the 604C.

The 605A/B were available concurrently with 604D, and then E. See below for more on the "backlash."

In around 1962, Altec went on a cost cutting exercise that saw the introduction of the 605 and 806.

The 605A came out in 1959. The price of a 604D was $177 at the time, the price of 605A was $175.

Studios balked at this product, considering it noticably inferior to the 604.

Such a failure that Altec kept producing it into the mid sixties, even making a B version.

605As were used at EMI Abbey Road to record nearly all the Beatles' music; they were used at Motown as their monitors (this comes from a senior Motown engineer); and they were used by Columbia Records which made some of the best sounding recordings of all time. Kind of Blue?

In particular, Capitol, a long time Altec customer, turned to JBL to supply studio monitors. They were impressed enough that they later standarized on JBL monitors for all of their studios. Soon JBL was supplying monitors to the industry at large.

A senior recoding engineer writes elsewhere: "The only major studio that was into JBL's in the 60's that I know of was Capitol/Hollywood." Hardly evidence of a deluge wiping Altec from the market. Secondly, if you were already satisfied with 604s the introduction of the 605 wouldn't make anyone get rid of an existing set of 604s.

In summary, the 605A was not an intrinsically bad speaker.

Everything you have written says the opposite.

Nonetheless, it was considered to be significantly different in sound from the 604 that it replaced.

Yes for the standard monitor cabinet, the 612, a 605A will produce deeper bass. Surely not a reason to not buy them. The 605A introduced the new accordion surround to the Duplex, lowering Fs and raising Q.