Altec 606 cabinets and which 604 to use

**cradeldorf** · January 2nd, 2013, 01:02 AM

53hz was free air. And I have seen 604E's all over the place even in Altecs literature. I've seen them as 25hz, 27hz, 30hz and so on. All I can say is both of my C's measured 53hz in free air using DATS to measure them. That's why I suggest just tuning the cabs to the speakers using the impedance method because then no matter what the Fs of the speaker is, they're tuned to the cabinet properly. If indeed you think the cabinet should be tuned to Fs.

GM · January 2nd, 2013, 02:22 AM

Originally Posted by cradeldorf

All I can say is both of my C's measured 53hz in free air using DATS to measure them.

This is way too high! OEM was ~40 Hz max or they didn't ship, at least this was the official marketing 'line'. Are they original?

GM

**Alien_Shore** · January 2nd, 2013, 01:00 PM

I bought a beat-up 604E from ePay and had GPA recone it, remag, new phram.
With the new VC and cone, it has a free-air resonance Fs of ~27 Hz.
I asked Santa for a router, but the elves are still working on it apparently

Maybe I will ask a local guy to do the baffle board for me and I can slap a test box together.

GM · January 2nd, 2013, 06:19 PM

The lowest OEM E series I've seen were around 25 Hz and others have listed ~27 Hz for new GPA later series and re-cones, so nice to see good consistency. What do you need a router for? Cheap jigsaws and a little patience works just fine.

GM

**cradeldorf** · January 2nd, 2013, 07:45 PM

Originally Posted by GM

This is way too high! OEM was ~40 Hz max or they didn't ship, at least this was the official marketing 'line'. Are they original?

GM

They are original, and almost 60 years old. (1954's) My guess is that the surrounds have hardened over the years and stiffened up. That was measuring them in the summer too. I'd almost bet that it is even higher in the winter because everything stiffens up in the colder months...well almost everything.

Probably why it seems like they sound better after they've been running for a couple of hours.

**HeathKitPat** · January 3rd, 2013, 10:16 PM

Just a follow up. I picked up my second 606 today this is the one with the 604C in it. The first cabinet I bought has a 601 in it that I have to replace with another 604c. I played the 604 today and had the opportunity to A/B it with one of my two Altec Valencia's that I added GPA HF drivers to and new crossovers that I built using high quality components. These Valencia's are near the top of as good as a Valencia can get. When testing I had the 604c on left channel, Valencia on right channel, preamp set to mono A+B. Tube preamp, Williamson monoblocks at about 30 watts per. The 604c has a bone stock crossover and compared to the Valencia it really shined. What an amazing sound. The combination of speaker and cabinet is wonderful. The first thought that came to mind when listening was "what presence". The music just jumped out at me as if it was in the room and not in a box. I can't wait to get to work on some custom crossover's with time alignment. I'm going to be looking for another 604c to add to the second cabinet so my need to figure out the LF resonance of an E and how to modify the cabinet accordingly won't be needed.