Far too lean 604-8Gs in 620 kabs

**KBergsson** · September 14th, 2011, 07:34 AM

Just removed the Altecs 604s and removed som fiberglass from 2 sides in each speaker. Initial impression: more open/transparent or lively sound. The bass membranes are stamped 1803035662 and 1803035(5or6) cannot se last two figures.
Does this indicate original membranes or later recones?
Regards
Kjartan

**Todd W. White** · September 14th, 2011, 11:33 AM

Be careful not to remove too much damping material - if you do, you'll set up some nasty standing waves inside, not to mention making the loss of perceived LF response due to wasting the energy wiggling the box.

**KBergsson** · September 14th, 2011, 11:38 AM

Hi Todd, I only removed damping from one side and bottom so that top, back and one side is still covered.
Sounds fine, but no change in bass output.
Regards
Kjartan

**speakerdave** · September 22nd, 2011, 12:38 AM

Originally Posted by KBergsson

Just removed the Altecs 604s and removed som fiberglass from 2 sides in each speaker. Initial impression: more open/transparent or lively sound. The bass membranes are stamped 1803035662 and 1803035(5or6) cannot se last two figures.
Does this indicate original membranes or later recones?
Regards
Kjartan

If anyone responded to this I missed it. Those are not Altec cone numbers for the 515b/604G, so they are apparently recones. I don't recognize the numbers, so i cannot place the source.

**KBergsson** · September 22nd, 2011, 03:45 AM

Originally Posted by speakerdave

If anyone responded to this I missed it. Those are not Altec cone numbers for the 515b/604G, so they are apparently recones. I don't recognize the numbers, so i cannot place the source.

Thanks speakerdave, that explaines why they look "new".
Regards
Kjartan