Altec 604-8g's how to improve?

[Terp]

Hi all,

I have a pair of 604-8G's that I love. They are in original Altec 612C cabinets and have new GPA crossovers. I was thinking about maybe different cabinets? Maybe add a subwoofer? Any ideas would be welcome.

Thanks!

[Phil-G]

Hi Terp, kinda slow here sometimes.
there's a lot of people here that can give you a few really good pointers. best i can come up with is, depending how old the diaphragms in the tweeters are, you could replace them with newer GPA ones. having not heard the 612 cabinets, it would be difficult to have a suggestion as far as a sub goes.
i use a sub with my 828 cabinets. makes a nice difference with them.

[gearfreak]

- what do you like about them
- what do you want to improve?
- would you go to a bigger cabinet?

Seems bass response is on the list -

The 612C is spec'd as 6.8 ft3, I don't see a cabinet tuning listed.

You might first get an idea of what you are dealing with,
- by measuring the impedance response of the LF section.
- by measuring the 'free air' parameter impedance response of the 604 itself.
A bass reflex should exhibit 2 peaks in the LF. So comparing/contrasting the two, you get a picture of what the cab is doing to the driver response as a matter of now being a system.

Then you can block off the port and see (while hearing) what difference that makes.

Then infer whether enlarging (or otherwise tweaking) the port is what you might want to do, or might want not to do.

I have 604's in 3154's (spec'd: 6 ft3) and have a bit of a hole from 55-80hz, maybe ranging a bit higher, ...to sort out.

[Terp]

- what do you like about them
- what do you want to improve?
- would you go to a bigger cabinet?

Seems bass response is on the list -

The 612C is spec'd as 6.8 ft3, I don't see a cabinet tuning listed.

You might first get an idea of what you are dealing with,
- by measuring the impedance response of the LF section.
- by measuring the 'free air' parameter impedance response of the 604 itself.
A bass reflex should exhibit 2 peaks in the LF. So comparing/contrasting the two, you get a picture of what the cab is doing to the driver response as a matter of now being a system.

Then you can block off the port and see (while hearing) what difference that makes.

Then infer whether enlarging (or otherwise tweaking) the port is what you might want to do, or might want not to do.

I have 604's in 3154's (spec'd: 6 ft3) and have a bit of a hole from 55-80hz, maybe ranging a bit higher, ...to sort out.

I like the midrange and "live" soundstage.
I would like more bass and a more cohesive sound (compared to my other speakers, PSB Imagine T3's)
I also would like a nicer looking cabinet, taller (ear level) and possibly larger CU ft.

I dont know how to do those measurments, ie LF frequency response etc.

Thanks

[bowtie427ss]

9 ft3 minimum ~ 40hz tuning, with a broad/wide baffle to control step response

Markwart phase corrected network, or just go active and don't look back.

Where's 604man with those 20+ ft3 boxes?

[Earl K]

Hi all,

I have a pair of 604-8G's that I love. They are in original Altec 612C cabinets and have new GPA crossovers. I was thinking about maybe different cabinets? Maybe add a subwoofer? Any ideas would be welcome.

Thanks!

Look to the Urei 813 or Urei 813A for some inspiration ( for filling out the bass ).

Google will find you the details.

[Earl K]

Some more info to get you started.

Urei 813 pdf

This product used the Altec 604-8G duplex along with a Eminence "helper woofer" ( which was 4 ohm I believe ) .

I would try various crossovers and see which one you like best.

The Urei is Time-Aligned, the GPA is whatever? while the Markwart variant is Phase Aligned ( if not Time Aligned ).

- Passive crossover parts are pretty cheap, build & try them all!

[604man]

9 ft3 minimum ~ 40hz tuning, with a broad/wide baffle to control step response

Markwart phase corrected network, or just go active and don't look back.

Where's 604man with those 20+ ft3 boxes?

HI, Yes just search "604-8g big cabinets big sound".

the cabs work good I gave the dimensions in the post .


604-8G.jpg

[Phil-G]

HI, Yes just search "604-8g big cabinets big sound".

the cabs work good I gave the dimensions in the post .


604-8G.jpg

unfortunately photoFuckit has your pictures hostage.
604 8G Big cabinets big sound

[rogerh113]

I built some 9 cu ft cabinets for my 604-8G, including Markwart crossovers. The bass goes low, and is tight and clean. I could not be happier. There is a thread on this board with all of the questions and responses from members here. Might provide some perspective on the larger cabinet option. With a bit of care, they might also meet the WAF hurdle.....