604E cabinets again

[kestudio]

Hi!
Having read a bit about those "Big Red Monitors" i?d like to figure out wether my understanding is correct:
Mostly advised to use the 620 cabinet for my 604Es i believe the Big Red Monitors contain the 604E in a smaller dimension cab - am i wrong? I also learned they use the MasteringLab crossover.
Is this the reason for the differing cab size? Got the layout for the xovers and am gonna build them anyway.
Does anybody have "sonical" experiences with 604E in the "Big Red Monitors" or similar cabs?
I?m convinced the 620 is the best cab - but as i know was developed along with the original x-over
that came with the 604E. Looking at the layouts it?s quite obvious they?re very different ;-).
So while i?m just beginning to build cabs - i?m looking for the "last wisdom".
When i bought the 604Es they were build in a cabinet that might have been a 620 type but was so ugly i can?t remenber clearly enough . . (black vinyl and transport wheels fixed to it - a stage-thing i thought and quickly took a screwdriver to get the chassis). They sounded not really good in those cabs: a bit dull and boomy - may be it was the electronics (some selfmade bipolar transistor sounding like a car-radio of the 60s).
Well - here i am a bit confused: like to start but . . . TSPs of the 604Es are a bit confusing too - programs suggest a 94L volume with f58Hz. 620 cab is about 240L at 40Hz i think. . . . .
I like a very clean, not (if i had to make a decision) very deep bass.

regards, Klaus

[selmerdave]

Klaus,

I was going to reply to your other post but I didn't think I really had much of use to tell you. The cabinets that I'm using for mine are considerably smaller than your 620's (around 4.5 cu ft) and I imagine that they don't sound as good but I can say that they sound pretty darn great, and while they are not as "perfect" sounding I would not pay the extra $1500 - plus for that last bit of improvement. What I heard from the big reds was briefer than I would have liked, but they sounded really full and even - true sounding. I suspect the reason that most studios used the big reds as opposed to something like the 620 is more a matter of practicality related to size. Probably the big reds were a good comprimise.

BTW, do you have a copy of plans for the 620's? Maybe someday...

Dave

[GM]

The ML XO has nothing to do with cab Vb. It's primary purpose is to electronically correct the acoustic phase mismatch of the LF/HF and I highly recommend acquiring or DIYing some.

You'll have to measure the specs of your drivers as part of the system's output impedance, your room's gain curve, at least the long dimension axial modes, and factor in speaker/listening position, etc., to arrive at the 'last wisdom' on cab design for *your* drivers/room.

As for the 620 being the ideal cab, this depends solely on the above considerations, and the specs I have for the 604E tells me it's way too large for a 40Hz Fb.

Frankly, if they were mine and the specs I have were 'close enough', then they would go into a ~225L vented cab with a JBL 2235 (or similar) tuned to whatever complements the room gain. Combined with the appropriate ML XO, I'd have a nice pair of early Urei 'clones'.

If these are too big, then just the 604Es in ~140L tuned to ~27-30Hz and stuck in the corners appears to be an acceptable tradeoff of LF output while maintaining excellent transient response.

If tube driven, then all this needs to be revised a bit since the amp's output impedance will increase Qts enough to either require a larger cab and/or lower tuning.

GM