604e cabinet and crossover

[billfort]

Hi Eisbar. As mentioned here, the cabinets I built for my 604-8G?s use the same volume and tuning as the 620A but I varied the shape and height for the reasons mentioned on my webpage. I am very happy with the results and believe a few key elements in my take on them where getting the driver center up to ear height and retaining the 26? wide baffle of the 620A. I have heard 604?s in narrower cabinets and exact copies of the 620A and prefer the upper bass/lower mid balance of the wider designs.

I use G?s but have heard E?s in both a very solidly built (1.5? thick HDF) 612 and an exact copy of the 620A in ?? Baltic birch (Mastering Labs crossover) and definitely preferred the 620. The larger volume doesn?t look quite so pretty when modeled in WinSID but the 620 just made for a better balanced bottom end and nicer overall sound. It might have been the volume/tuning, larger baffle going to the floor (the 612?s where on low stands) or maybe cabinet construction but the choice was pretty clear.

I did mess around with different insulation/stuffing configurations in my cabinets and found that you can certainly overdo it and kill some of the life and dynamics with too much. The best balance I found was a thin layer (maybe 1 ??) of fiberglass on the back, top and 1 side only.

I currently use a Jeff Markwart crossover (paper-in-oil caps, copper foil coils) and am very happy with it but do consider it a bit of a work in progress. I eventually want to replace all the resistors and the level pot with something like Mills wire-wounds and mount it all in a pretty external enclosure but I?m so busy enjoying it as-is I just never get to that.

I hope your project turns out to your liking and you get the kind of enjoyment out of the 604?s that I do.

btw Klaus; Nice to see you got your 604's all sorted. Doing the active thing huh? I keep thinking I'm going to try that but you know what tube guys are like, don't want all the SS stuff in there.

[klausesser]

<btw Klaus; Nice to see you got your 604's all sorted. Doing the active thing huh? I keep thinking I'm going to try that but you know what tube guys are like, don't want all the SS stuff in there. >

Hi Bill!

Good to see you! Yes - i?m almost finished ;-) . . .
The 604E?s running "delightfully" (i like that word :-) ) and the xover is almost ready - need to solder the res. and to find the point for the delay.

I understand completely your tube-thing . . i?ll do a passive xo (Jeff?s suggestion) and will look for a fine triode also.

Nothing to say against running both worlds, is it . . . ;-)

My cousin from Toronto ist just visiting us - worldcup, you know . .

best - and we?ll keep seeing, ok? Klaus

[HeartFixr]

Hello Eisbar,
I am new to this blog but am quite interested in the Stonehenge V design. Could you copy to me the building blueprints, please?
How would you compare the sound quality of the duplex 604 series to building a speaker with separate horn and bass woofer? If you could only take one to a remote island, which would you prefer?

Thanks

[selmerdave]

Bill,

Would you mind commenting a little further on the difference between the 620's and the narrower cabinets you heard? Can you go into a little bit more detail about the difference in the upper-bass/lower-mid? Also could you comment on any difference in terms of imaging? Many thanks.

Dave

[Todd W. White]

The Stonehenge V is heavily braced:

* Diagonally across the back.
* Horizontally below the opening and above the port (I like the rectangular vent better than a hole).
* Front-to-back bracing on either side, along with diagonal's too.
* A diagonal across the top.

All are made from stock which has been ripped to 1.5", then glued and screwed in place.

Insulation is on the:

* Back.
* One side.
* Top.

All is fiberglas, approximately 2" thick, secured with glue and fasteners ala early Altec (namely, wood screws holding cardboard squares that hold the insulation in place).

[eisbär]

Dear readers, members, fans of altec duplex

please let me first correct myself as I did in another post before: I don?t have a drawing of the Stonehenge V!!!! It?s just the Stonehenge III and that?s an entirely different loudspeaker!!! It?s too small for a stisfying bass reproduction as Todd explained in his post. Sorry guys :-(

Unfortunately my project didn?t do any progress up to now. My girlfriend is moving and becoming self employed so I?m spending all my time on constructing/building some furniture for her (during my leisure time - I?m not a professional carpenter). Well, that?s not a bad job however ... no loudspeaker for me :-((((((

Finally I?d like to tell you my plans for the SH V:
Todd told us the dimensions and subtracting a pedestal of 2.5 in you have 47,5 x 22 x 18 (H,W,D). Using 0,75 in board you get internal measures of 46 x 20.5 x 16.5 wich leads us to a volume of 15559.5 in^3 or equivalent 9.00 ft^3.

Since I live in Europe and we only have metres and centimetres here I did the rest of my work in cm: I?m going to use 2 cm mulitplex (multilayer beech or birch plywood) with the outer dimensions of 114 x 55 x 45 (H,W,D). Placement of the driver in the encolsure seems to be less crucial than placdement of the driver on erar?s height. So I decided to place it 86,5 cm above ground. Then it is also placed symmetrical that means space between driver and sides/top is 8.5 cm. Placement and shape of the port? I don?t think that really matters. Just the size is important. So I?ll copy the dimensions of the 620 maybe as a circle - that?s easier.

BTW a question: Has the port to be bigger or smaller when it gets longer? However, my port will be 1 mm longer than the original one ;-)

What?s left is the bracing and the dampening. Some of the bracing can be seen on Todd?s picture. In another thread in this forum I read the SH V is only dampened on one side and the back. Concerning both issues I?ll have to do some experimental work. Helpful comments are always welcome.

I hope I?ll be able to start building at the end of summer ...

Greetings eisb?r

[stlblue]

Help for a newbie, please.

What should the port size/shape/location be for 604E's (w/ Iconic crossover) if I were to build a pair of Stonehenge V's? As I understand it, the amp used can make a difference...my 604E's will be used w/ a 5 watt el84 amp (Glow Amp One).

Many, many thanks...

[stlblue]

Anyone?

[klausesser]

Help for a newbie, please.

What should the port size/shape/location be for 604E's (w/ Iconic crossover) if I were to build a pair of Stonehenge V's? As I understand it, the amp used can make a difference...my 604E's will be used w/ a 5 watt el84 amp (Glow Amp One).

Many, many thanks...

Hi!

The 604E is a bit "special" - it really needs 9cub.ft . . . no way around it.
There are some 620 plans on the web:
ALTEC PLANS

best, Klaus

[drummerwill]

Hey STLBlue are you in St Louis? If so , me too!

If you are interested in 604 cabinets, I got a pair of 604-8K's in a MLTL like cabinet,
if you'd like to hear them.

Here's a link to some pics, : The AudioCircle Gallery - Altec 604-8K's/Baltic Birch Cab 4



Have fun.