Embiggening the Altec 620. Thoughts/experiences with >9 cu ft cabs for Altec 604-8g?

[Baaronj]

Hey folks. I'm ready to start planning for construction of replacement - hopefully permanent - enclosures for my Altec 604-8gs and would really appreciate hearing your thoughts or experiences on just how big I should go.

Having heard the 604-8g in a variety of enclosures - the largest being the 620 - I consider the ~9 cu ft of the 620 as a minimum volume. Not really interested in narrow baffle types or MLTLs - I like the wide baffle sound. Willing to keep an open mind though.

My 604s are currently in some derelict 620 cabs, which among other indignities suffered before I found them were 'modified' by a pro audio roadie to house a Peavy driver and squawker of some sort, which was housed in the clumsily enlarged front crossover opening.

I fixed them up as best I could, which required enough bondo to get an old Alfa Romero street worthy, and they do sound great. They don't rattle or anything.

But I believe they'd sound much better in well well-constructed cabs. Even if they sounded the same in new cabs, my bondo work leaves something to be desired - sculpting a nice square corner from bondo ain't easy - so they've gotta be replaced.

Anyhow, I'm intrigued by the idea that the 604s could sound even better in larger enclosures than the 620.

Does anyone have any experience with 604s in *really* big boxes?

The big Shindo 604e Latour enclosure is ~11-12 cu ft.

Hiraga Onken cabs are 12.7 cu ft (I know these are designed for the 416, but I think there's some precedent for using 604s in these).

I've heard of people running 604a in A7 cabs and liking them, even though it seems 'wrong.'

I know it's bananas, but the big old Jensen folded horns are interesting. Anyone heard 604s in back loaded/folded horn designs?

Are there tradeoffs to the improved LF extension/authority that something like the 'sane maximum' ~12 cu ft neighborhood would achieve?

These will probably be the last cabs I'm able to implement for the 604s for the foreseeable future, so I'd like to go for the gold here.

Appreciate any and all guidance you all are willing share.

 

[marantzfan]

How timely....

Since completing my Onken build and hearing what 416-8a's can do in those boxes.....I have to be honest I'm curious what my 604-8G's would sound like in there.

The mid-bass from these cabinets is so much more visceral then I ever remember hearing from my Model 19's.

With that said, I seem to remember reading in a few places where folks were less than enamored with 604's in Onken cabinets...

I'll be honest, it will likely be a while till I have the desire to tear both systems apart to make the comparison. Maybe someone that has actual ears on experience can comment.

 

[Baaronj]

How timely....

Since completing my Onken build and hearing what 416-8a's can do in those boxes.....I have to be honest I'm curious what my 604-8G's would sound like in there.

The mid-bass from these cabinets is so much more visceral then I ever remember hearing from my Model 19's.

With that said, I seem to remember reading in a few places where folks were less than enamored with 604's in Onken cabinets...

I'll be honest, it will likely be a while till I have the desire to tear both systems apart to make the comparison. Maybe someone that has actual ears on experience can comment.

I'm trying to imagine midbass more visceral than Model 19s. Are you running 416a or b?

I've read those kinds of comments about 604s in Onkens as well. To be fair, I recall reading more "they probably wouldn't be good" comments than first hand reports.

I have read positive things about enclosures up to 20 cu ft, and have often seen knowledgeable folks say something along the lines of 'bigger is better.' My question has always been how much bigger and how much better. My understanding has always been the bigger the better, up to a point. There are people who swear by those 20 cuft cabs.

I've been looking into this cab issue for the 604s for what feels like forever. I've got the exact dimensions of the Shindo enclosures and a few others saved around here somewhere.

I'm not wild about the looks of the Shindo enclosures, but I'm hoping whatever I wind up with will allow me to get the horns up to ear level, which the Shindo seems to have been designed to do. The big Latour enclosure puts the horn close to the top edge of the 620 enclosure (~42" of memory serves), which is about where I'd need it.

I was close to saying to hell with it and trying Onkens at one point, but my wife isn't crazy about their aesthetics. Not a no go, but they'd require astute salesmanship on my part as to their unmatched sonic virtues.

If they didn't live up to my hype, I could see a precipitous drop in my own domestic-audio-political capital which could imperil the possibility of future, even more ridiculous pieces of audio equipment in our home.

Hoping others will chime in too. If I'm not able to get sufficient first hand information, I'll probably wind up designing an embiggened 620 that raises the horn up to where it should be. Probably ~12-13 cu ft.

 

[ICTWoody]

Following closely. I gots 604-8G’s. :-)

- Woody

 

[jeb98]

I can't say specifically how the 604's will sound in the Onken cabinets but I do feel the 604's and the 416's are very different in terms of bass response. I get more bass out of the 416's than any 604 iteration I have heard, in the same cabinets (only tried up to 9 cubic feet).

 

[Baaronj]

I can't say specifically how the 604's will sound in the Onken cabinets but I do feel the 604's and the 416's are very different in terms of bass response. I get more bass out of the 416's than any 604 iteration I have heard, in the same cabinets (only tried up to 9 cubic feet).

Totally agree with this. I had the model 19s and 604s in the same room for a little while... the difference between the two in LF response is not subtle.

I am still really intrigued by some of the other ultraflex type implementations for the 604 - all of which I've come across originating in Asia, if not specifically Japan.

I do love the look of the Utopia cabinets. I also seem to remember seeing a few examples of 604s in upside down Jensen Imperial corner horn enclosures, which I think look gorgeous.

I'll edit this a little later with some pics.

 

[Audionut]

Totally agree with this. I had the model 19s and 604s in the same room for a little while... the difference between the two in LF response is not subtle.

I am still really intrigued by some of the other ultraflex type implementations for the 604 - all of which I've come across originating in Asia, if not specifically Japan.

I do love the look of the Utopia cabinets. I also seem to remember seeing a few examples of 604s in upside down Jensen Imperial corner horn enclosures, which I think look gorgeous.

I'll edit this a little later with some pics.

Although I really like my 602’ish cabinets at about 9 cubic ft., I thought of, and would still consider building utopias; uber-wide baffle and great looks! I’ll have to check the volume on those.
Not sure what amp you are running but have you considered a push/pull 6v6? My HK A300 squeezed more bass out of my 604E’s than any other amp (2a3, 300b or el84).

 

[Baaronj]

Although I really like my 602’ish cabinets at about 9 cubic ft., I thought of, and would still consider building utopias; uber-wide baffle and great looks! I’ll have to check the volume on those.
Not sure what amp you are running but have you considered a push/pull 6v6? My HK A300 squeezed more bass out of my 604E’s than any other amp (2a3, 300b or el84).

I hadn't considered PP6V6 until you mention it, but I had an eye-opening experience yesterday with big power behind the 604s.

Up until yesterday, I think 25 watts is the most I've heard pushing my 604s, but otherwise it's mostly been lower power designs: Art Audio PX-25 (still the most gorgeous, clear sounding amp I've yet heard), Line Magnetic 845 amps, Allnic 300b, a slew of el84 push pulls and SE designs, 6V6 SE, etc.

Yesterday, a close friend who's about to move overseas for a few years brought most of his equipment over to live at my place until he returns to the states. Sweet!!

He was running a pair of c. 1990s Mirage flagships - huge black monoliths that are the single heaviest piece of home audio equipment I've ever had the herniating displeasure of lifting. I only got to hear them once briefly, but they made the spookiest imaging I've ever heard. The music seems to emenate from everywhere in the room except where the speakers are standing. I understood why they landed on 'mirage.'

Anyway, his main amp was the 100watt/channel Conrad Johnson Premier Seven. Eight kt77s. Preposterously large and heavy. I watched the distribution transformer on the telephone pole outside when we flipped the 'on' switch for signs of distress.

To my ears, it sounds gorgeous on the 604s. Like you said, much better bass and control of LF than lower power amps. Really fun. All the (good) CJ attributes. Given the efficiency of the 604s, I was expecting there to be some sonic indication that you can RIDE THE LIGHTNING with this amp, but it's super smooth and refined.

Not saying better than any of the others - we played it back to back with the 1.x watt SE 6V6 project amp, which also sounds wonderful.

So cool that one can even use such disparate amps on the same speakers with great results.

I've read comments from people (usually pro audio and studio guys) over the years who swore by massive power for the 604s.

It was neat to finally hear it firsthand. Felt like I was working on mixdowns for a new REO Speedwagon live album, c. '84. Where's my muscle shirt?

 

[jrocker]

Isn’t the trade off with varying volume a function of lower frequency reach versus transient snap? And, can’t minds differ?

 

[Baaronj]

Isn’t the trade off with varying volume a function of lower frequency reach versus transient snap? And, can’t minds differ?

This is exactly what I don't know. I've mainly read comments from speaker design folks that, essentially, larger box volume = greater LF extension. I don't recall seeing comment re the what tradeoffs are involved above the LF band in the 604 specifically. It's hard to imagine there wouldn't be some effect.

Actually, I had forgotten about this, but my 604s were stuck in little (2.9 sq ft - empty) 614 cabinets for almost a year until I found some beat up 620s. I've got RTAs on them in the 614s around here somewhere.

I didn't notice any loss of transient attack when I moved them into the 620 cabs, but to be fair, I was so enthralled with the big sound I don't think I would have noticed.

Not sure if you meant 'minds differ' or (as a possible typo) 'mids differ', but in either case, I say absolutely! Personally, I'm way more interested in hearing others' thoughts and opinions on all this stuff than I am specs and numbers.

 

[Baaronj]

Here's what got me thinking about 604s in Jensen Imperial cabs. Notice the cute little Model 19 barely in frame on the right.

 

[jeb98]

Here's what got me thinking about 604s in Jensen Imperial cabs. Notice the cute little Model 19 barely in frame on the right.

I just got to hear some Jensen Imperial cabs with the original G610B Jensen triaxial speakers this weekend! Those are some big cabs for sure

 

[Baaronj]

I just got to hear some Jensen Imperial cabs with the original G610B Jensen triaxial speakers this weekend! Those are some big cabs for sure

Really cool. What did you think about 'em?

 

[J. Frum]

Y’all need to get religion with regard to enclosure simulation. With T/S parameters, modeling a basic bass-reflex cabinet is easy and accurate. It’s a brave new world.

You’ll learn all about the delicate balancing act between the driver’s electromechanical properties, enclosure volume, and tuning. It’s a lot more complicated than “bigger = better”, and you’ll see the effect changes have on frequency response, power handling, and group delay.

I’ve modeled the 604-8G every which-way, and I can’t come up with anything that’s better overall than a 9 cu. ft. cabinet tuned to about 40 Hz. - essentially, a 620.

I’ve said it before, and I’ll say it again: It’s almost like those Altec engineers knew what they were doing.

 

[jeb98]

Really cool. What did you think about 'em?

They’re interesting, very large soundstage, which I didn’t get as much of with 604’s (I’ve had 604C and 604E). Imaging wasn’t super pinpoint, and I detected some honky-ness in the upper midrange. Not sure if it’s due to the phenolic RP-302 tweeter or the midrange driver it uses? It was at a friends place so I didn’t listen to the music I normally listen to in the way I normally listen either.

 

[rjwolf]

I put some 605s in a Greg Monfort designed MLTL 16 cu.ft. box
Altec MLTL with Model 19 drivers
Its is the same footprint as a model 19 but taller.r.

 

[Baaronj]

Y’all need to get religion with regard to enclosure simulation. With T/S parameters, modeling a basic bass-reflex cabinet is easy and accurate. It’s a brave new world.

You’ll learn all about the delicate balancing act between the driver’s electromechanical properties, enclosure volume, and tuning. It’s a lot more complicated than “bigger = better”, and you’ll see the effect changes have on frequency response, power handling, and group delay.

I’ve modeled the 604-8G every which-way, and I can’t come up with anything that’s better overall than a 9 cu. ft. cabinet tuned to about 40 Hz. - essentially, a 620.

I’ve said it before, and I’ll say it again: It’s almost like those Altec engineers knew what they were doing.

B-b-but that would mean sticking with what I've got, and then what would I have to do with all my spare time - play records?

Kidding aside, there's a lot of validity to this. It's been a while, but I've spent some time in WinISD looking at box volume on the 8g, and I remember the seeing the curve look nicest at ~9 cu ft. I seem to recall a bump happening around 80-100hz as box tuning went higher than 9 cu ft, but I could be thinking of dual 414 models.

Thing is, these kinds of projects are so time consuming and hard to get off the ground with all the other domestic priorities, I want to be real real certain I'm going with a design I can live with for a while.

Mainly though, I just wanted to hear from folks who've owned or heard the 604s in bigger cabs. There are *just* enough >9 sq ft builds out there, and anecdotal praise for them, to make it tough for me not to explore the possibility.

 

[Baaronj]

I put some 605s in a Greg Monfort designed MLTL 16 cu.ft. box
Altec MLTL with Model 19 drivers
Its is the same footprint as a model 19 but taller.View attachment 37706View attachment 37707r.

This is impressive. I'm about to check the link you posted.... but were you happy with the sonics?

 

[Olson_jr]

I have nothing to add to this thread other than the fact that I love the word Embiggening.

I believe that was from The Simpsons.

​

 

[rjwolf]

B-b-but that would mean sticking with what I've got, and then what would I have to do with all my spare time - play records?

Kidding aside, there's a lot of validity to this. It's been a while, but I've spent some time in WinISD looking at box volume on the 8g, and I remember the seeing the curve look nicest at ~9 cu ft. I seem to recall a bump happening around 80-100hz as box tuning went higher than 9 cu ft, but I could be thinking of dual 414 models.

Thing is, these kinds of projects are so time consuming and hard to get off the ground with all the other domestic priorities, I want to be real real certain I'm going with a design I can live with for a while.

Mainly though, I just wanted to hear from folks who've owned or heard the 604s in bigger cabs. There are *just* enough >9 sq ft builds out there, and anecdotal praise for them, to make it tough for me not to explore the possibility.

The Westend build thread is great.
This was designed for a 416 so i figure a 605 would work just fine.
I had to change the design slightly to accommodate the A vs B frame.
The bass goes way lower than the model 19 and feels more balanced in the low end to me.