New cabinets for Altec Model 5 woofers

[buzz_cdn]

Some time ago I had gotten a pair of Altec Model 5 cabinets for $5 with a little water damage and the foam degrading on the alnico woofers. Accepting the 70's vintage (warmer tone than new stuff), I was extremely pleased with the overall bass performance of these 2 way boxes which was warm and tight (again considering their era). My comparison point for clean sound was Monitor Audio Silver 8's with a Sony ES80 preamp, Cyrus CD transport and Anthem power amp.

I have refoamed the drivers (professionally) and now the boxes are tending to boomy (I don't get this, I thought they would get firmer not softer sounding). Maybe my tastes have changed or the cabinets are just resonating more now. I know that a person's "sound memory" is very fleeting.

Before and after were driven with the same Sony ES80 preamp, Cyrus CD transport and Anthem power amp.

If anyone is familiar with or has measured the specs for the Model 5 woofers I'd love to hear about it so I can redesign the cabinet (I planned to rebuild them anyways).

Otherwise, perhaps someone has experience with using a particular cabinet size or different port size to tweak this driver and could share. My thought was to reduce the cabinet size (10%?) and keep the same port size as well as making more rigid cabinets.

Thanks for any help or suggestions!!

[Zilch]

There is a process for doing this. You need:

1) The actual model number of the Altec woofer.

2) Luck that the Thiele/Small (T/S) parameters for it are available.

3) The interior dimensions of the existing box.

4) The size and depth of the port.

5) A box modeling program such as WinISD, which is free.

6) An estimate of how much box volume is occupied by other stuff.

7) Ideally, a measurement of at least the Fs of the refoamed driver to verify that it conforms with the original spec.

Someone else will have to sort out boomy and softer; they don't correlate to me....

[speakerdave]

Perhaps the new surrounds have raised the resonance enough to detune the system. Work them hard for several days to break them in. You could hook them up out of phase and set them face to face and put Tiger Lily or Ernest Ranglin's Bassline on repeat. When your bass is working those two CD's sound good.

David

[buzz_cdn]

Thanks for the comments.

The woofer is not one of the famous cast frame types so I have not been able to find any postings for its T/S values based on the number on the back of the woofer. This is why I was asking for any measured values. I am not set up to check this but may end of doing that.

Regarding the possible detuning from the driver refoam, I remembered that I had changed the type and amount of batting in the cabinets before the refoaming to adjust the tuning (for the better). So I reduced the amount of stuffing after your replies and there is a noticable improvement.

I am also still getting cabinet resonance so I am going to play with that as well to dampen the bottom end.