Posted by Wayne Parham on November 09, 2003 at 15:41:07

In Reply to: Pi seven port size using Altec 421A 15" Drivers posted by jumpin on November 09, 2003 at 12:45:11:

According to "Great Plains Audio," Altec specs for the 421-8H are as follows:

Vas = 12.8ft³
Fts = 32Hz
Qts = 0.25

Based on these values, PiAlign recommends a 3.2ft³ cabinet tuned to 48Hz using a port that's 7.5" long, 4.6" tall and 8.2" wide.

Response is nice and flat with 60Hz f3 and 40Hz f10.

If this isn't the driver you have, you might consult the Altec T/S Specifications chart at Great Plains Audio to obtain the specs you need.