Altec 602D enclosures

[jcephusg]

Hi,
I Have a set of Altec 602Ds mounted in homemade enclosures that are too small. It has been recommended that they need proper sized enclosures that are in the 5-6 cu ft range. Does anyone have any sketches or plans for the proper enclosures for these? Any help would be greatly appreciated. Thanks

[RMC]

Hi jcephusg,

I looked quickly in my Altec stuff but didn't find any plans for the 602D. Sorry. However, the following concept may help you decide in which direction to go re cabinet size.

Assuming that a 5-6 cu.ft. box is a proper volume for the 602D, I would tend to go with the larger 6 cu.ft. instead of 5 cu.ft. the reason being that older coaxial or duplex drivers tend to be more lossy woofers. Therefore, an increase in box volume is often required to compensate for the air losses that impact low-frequency response.

Keep in mind larger boxes tend to be more lossy, and duplex drivers also, a "double whammy".

In other words (technical terms), a box loss assumption in the range of QL 3-5 (creating a larger cabinet) is probably more logical here than using a standard box loss of QL 7. The lower the QL number the more losses and the larger the cabinet has to be to achieve the same LF response as a standard QL 7 box for example.

You might have to play this by ear (trial/error method) in terms of deciding which box size to use and/or vent tuning frequency, if a vented box is chosen, to get the LF performance level that suits your needs.

I have not seen any Thiele/Small parameters for the 602D, since these are pretty old, another reason you may have to go with trial/error method, unless you find data/plans from someone who's been there before. Regards,

Richard