Gpa 416-8c

[gortnipper]

It is illegal to put a 604 in a 1.5 cu ft box!

10 cf box...

Using the measured plus derived specs [attached], it will need to be tuned lower [Fs] to get a 'close enough' similar response, so will probably need at least a 6” long vent.

GM

Thanks. And keep the 3.5R or no?

[VolvoHeretic]

sorry, last time I checied, 42.5 liters equealed 1,5 cubic feet.

[GM]

Thanks. And keep the 3.5R or no?

Hmm, IIRC, the 3.5 ohms was due to Jay's tube amp, so was tuned to the Iconic/GPA's Fs to maximize power conversion and you used it too.

Anyway, as a general rule for HIFI apps, I prefer/recommend an Fs or lower tuning and EQ if necessary to flatten it out in-room, but if you’re using a typical SS or tube PP amp, then try the cab as is first without any added resistance.

GM

[gortnipper]

sorry, last time I checied, 42.5 liters equealed 1,5 cubic feet.

Sorry, I copied out of GM's doc to Jay and L=Length of the internal longest dimension of the cab, not Liters. So, ~10.3 cu ft.

Hmm, IIRC, the 3.5 ohms was due to Jay's tube amp, so was tuned to the Iconic/GPA's Fs to maximize power conversion and you used it too.

Anyway, as a general rule for HIFI apps, I prefer/recommend an Fs or lower tuning and EQ if necessary to flatten it out in-room, but if you’re using a typical SS or tube PP amp, then try the cab as is first without any added resistance.

GM

OK, thanks again.

BTW - with the 604s in that box and my SE valve amp, I tried first w/o any added R and it sounded flat and thin. I then used a variable and found ~3R works very nicely so I added a fixed r.