ALTEC 604-8G help required...

[Horn Fanatic]

Hi folks -

I'm having a Hell of a time designing an enclosure for the 604-8G. I'm using Bass Box Pro, and by entering published T-S parameters I'm getting graphs I have never seen before. To say the least, half of them look squirrelly! I have checked and rechecked the parameters, and can't find a single flaw. I have had excellent luck tuning for the GPA 604-8H III, and many other drivers, but the 8G is throwing me for a loop. What ever volume I enter results in some very ugly graphs. I have reviewed many of my other designs on two different computers which are correct, so I don't believe my program has been corrupted.

The 8G system will be depolyed in a recording studio, not the control room. Can anyone provide me dimensions for the single driver Big Red monitor? The tuning appears to be much different than the 934 enclosure and Stonehenge III.

H.F.

[speakerdave]

Hi folks -

I'm having a Hell of a time designing an enclosure for the 604-8G. I'm using Bass Box Pro, and by entering published T-S parameters I'm getting graphs I have never seen before. To say the least, half of them look squirrelly! I have checked and rechecked the parameters, and can't find a single flaw. I have had excellent luck tuning for the GPA 604-8H III, and many other drivers, but the 8G is throwing me for a loop. What ever volume I enter results in some very ugly graphs. I have reviewed many of my other designs on two different computers which are correct, so I don't believe my program has been corrupted.

The 8G system will be depolyed in a recording studio, not the control room. Can anyone provide me dimensions for the single driver Big Red monitor? The tuning appears to be much different than the 934 enclosure and Stonehenge III.

H.F.

Published parameters can be wrong. Smith and Larsen WT2 (http://www.ht-audio.com/pages/WooferTester2.html) will tell you what you need to do with your drivers.

The Big Red, and the UREI 811 based in it, are designed for soffit mounting, so they will be bass-shy otherwise.

The UREI employs a resistive port.

The Big Red uses a 16ohm woofer section.

Why not use Altec's 620 or variations thereof? (e.g. Billfort's)

Lampton and Chase designed a 5 cu ft box for the 604-8G to be mounted in an upper corner in an early Audio Amateur issue.

Wayne Parham at Audio Roundtable suggests "a 5.5 cubic foot box tuned to 42Hz using a port 9.5" long and 9" diameter. You can also make the port rectangular, 10.5" x 6" and 9.5" long. These are inside dimensions of the port, and also inside dimensions of a cabinet. No displacement volume has been added, so you'll want to offset some for the space taken up by the parts inside."

How much bass do you need?

[Horn Fanatic]

Published parameters can be wrong.

The Big Red, and the UREI 811 based in it, are designed for soffit mounting, so they will be bass-shy otherwise.

The UREI employs a resistive port.

The Big Red uses a 16ohm woofer section.

Why not use Altec's 620 or variations thereof? (e.g. Billfort's)

Lampton and Chase designed a 5 cu ft box for the 604-8G to be mounted in an upper corner in an early Audio Amateur issue.

Wayne Parham at Audio Roundtable suggests "a 5.5 cubic foot box tuned to 42Hz using a port 9.5" long and 9" diameter. You can also make the port rectangular, 10.5" x 6" and 9.5" long. These are inside dimensions of the port, and also inside dimensions of a cabinet. No displacement volume has been added, so you'll want to offset some for the space taken up by the parts inside."

How much bass do you need?

Thanks for your reply -

The 620 volume will be too large for the environment. I'll enter your information into the program and check the results. I haven't gotten much information from my customer yet, I'm only at the number crunching stage right now, and will present the data for his approval. These speakers will be used as an alternative to his existing main system which is comprised of a pair of stock A7's, but using the ALTEC 909 compression driver. I'm not a big A7 fan, but I have to admit his system sounds very good. The 5.5 cf volume sounds more reasonable, as it is approximately that net volume that works best for the 604-8H III.

Regards, H.F.