Comparison of 604E vs. 604G

[longdrive55]

Hi All,

I am contemplating purchasing a pair of either of these duplex models. From what I've read/seen, the differences are:
-Speaker baskets (604E with white old style basket and 604G with newer gray cast basket)
-Some 604G's had tangerine phase plug
-604G's might have had a different crossover
My questions are:
1) Are the 604E's with the older basket a different diameter than the 604G's?
2) If not, do they use the same woofer cone?
3) The 604E's have the fins on the backside of the basket by the mounting holes. Do these prevent mounting from outside of the enclosure?
4) Are the newer woofer baskets preferred over the older for any reason?
5) Any sonic differencese between the two (assuming the 604G has the same older phase plug as the 604E's)?
6) Any differences in crossover?

Thanks for any help you can provide.

Erik

[GuyL]

1) Are the 604E's with the older basket a different diameter than the 604G's?

Yes, the older basket diameter is 15" and the cast basket is 16".

2) If not, do they use the same woofer cone?

They look the same but the 604E has 16 ohm and the G is 8 ohm.

3) The 604E's have the fins on the backside of the basket by the mounting holes. Do these prevent mounting from outside of the enclosure?

It makes things difficult but not impossible. You'll need to do some woodwork to accomodate the fins. you might try a gasket with no mods.

4) Are the newer woofer baskets preferred over the older for any reason?

The cast frame, keeps the voice coil permanently centered, in the flux gap even with the heavy alnico magnets and also improve the heat dissipation and power handling, compared to the earlier versions.

5) Any sonic differencese between the two (assuming the 604G has the same older phase plug as the 604E's)?

Probably not big differences.

6) Any differences in crossover?

They are difference. The 604E is a 16 ohm driver and the The G is 8 ohm. I think that the crossover point is the same. They might be other differences as well.

There's a later version of the 604E called 604E2 which has the later 16" cast basket and tangerine phase plug.

[longdrive55]

Guy,

Thanks for the detailed response.

Erik

[jmarkwart]

Longdrive55,
Let me add a bit more to GuyL's response about the crossover differences. They were major. The N1500A filter supplied with the 604-E used a first order high pass and second order low pass, and was a series filter, i.e., the voice coil loads were placed in series across the amp's output. The 604-8G filter, besides being 8 ohms, used a third order high pass and second order low pass, and had its loads placed in parallel across the amp's output.
Having said that, did they sound very different? Like GuyL said "probably not".
The big improvement in 604 crossovers, in my opinion, came with the mid-frequency EQ Altec introduced with the 604-8H. Not only does it sound different than the 604-8G, its EQ technique can make all older 604s sound much better too!
Jeff

[Kevin Gray]

Hi Erik,

I'll jump in here. I prefer the 8G, although I've heard very good Es as well. The 8G is the one that will give you the flattest bass. Try them all out for size in a Thiele and Small program and you'll find in a 6 cu ft cabinet tuned to 36Hz, it's F3 is about 45. Not bad for no sub. Only the 605 comes close, surprizingly. And Jeff is right...proper mid EQ, x-over slopes and phasing is the ONLY way to make them sound really Hi-Fi.

Best,

Kev

[zelgall]

A question for GuyL. I have both 604e's and 604-8g's, both have cast frames but are different in shape and as you mentioned mounting style. Why do you think that the 604-8g's will support the speaker better? Niether pair of mine are exhibiting any droop or bending and the E's are very old.

[Don McR]

I don't believe there was a distinct break between the 604E and 604-8G since there were evolutions within each model name. Somewhere I have an old spec sheet that refers to the 8 ohm conversion of the 604E as the 604E-8G, which was subsequently contracted to 604-8G. This is why there never was a 604-8F. It looked identical to the original 604E and still used the white 15" frame.

The 16" black frame had nothing to do with any engineering requirement. Brazil, in support of a fledgling pro speaker industry, imposed massive duties on imported loudspeaker components. However, they only applied on drivers up to 15" in diameter. Altec upped the diameter of their drivers as a way of avoiding their duties and maintaining a presense in this significant South American market. The ad copy about the greater strength came later Once converted to the 16" black frame, there was a futher change in the 604-8G with the introduction of the tangerine phase plug. Production changed to this device in 1976 with no change in model number. Therefore, 604-8G's can be found with either the older circumferential phase plugs or newer radial phase plugs with no indication on the driver label. I'm not entirely sure when the cross-over design changed, but was most likely introduced with the original 8 ohm E version and before the 16" frame G version.

[GuyL]

I was just quoting what Altec claimed regarding the advantage of the 16" cast frame basket over the earlier 15".

[zelgall]

I made a pair of crossovers based on Jeff's work and they are WAY better than the stock units in the 8g cabinets. A big thanks to Mr Markwart. I have the parts to do the same for the 604E's, should be nice.

[Todd W. White]

According to Jerry Hubbard, the real main difference is the impedance - the "E" is 16 ohms and the "G" is 8 ohms. Both use identical software.

However, as Don mentions, later G's had Tangerine phasing plugs, which would make a difference. Of course, the physical differences, such as the frame and paint color, don't affect the way they sound...

As I recall, the real differences lay in the crossovers - the xo's for both were very lacking.

Iconic Mfg. Co. has Jerry Hubbard working on an entirely new crossover for the "E". He has an "E" with original software and has been measured to make sure it is performing to spec, and is using it wo make sure the crossover works properly. It's already about 75% done, and (hopefully) will be ready for production late in November, if not sooner. Calling it the <font size="3">SUPER</font>Crossover, the men of Iconic believe that it promises to be the best passive crossover made for the "E".

Ever.

Since the speakers are very similar, with the exception of impedance, Iconic hopes that a new <font size="3">SUPER</font>Crossover for the "G" will soon follow. Of course, a special model for those G's with Tangerine phasing plugs will be necessary for those who own that version of the model.