Box for American Bass HD-15

[certifiedquality]

I'm designing a box for a single American Bass HD-15 and have run into a snag using WinIsd. The specs for the sub online are as follows:

FS: 31.7 Hz.
Cms: 81.5 Um/N
Mms: 457.5 g

However, when i enter Cms and Mms into Winisd it automatically calculates Fs as 26.06 Hz. I'm not sure how this discrepancy will affect the box design. I've seen differences of like around 1 Hz but not this big a difference so i'm not sure how to proceed.

[Joe X]

Try entering parameters for a Fi woofer, see if that happens

[certifiedquality]

Try entering parameters for a Fi woofer, see if that happens

Good idea! Unfortunately Fi is over my already stretched past the limit budget.

[Triticum Agricolam]

I'm designing a box for a single American Bass HD-15 and have run into a snag using WinIsd. The specs for the sub online are as follows:

FS: 31.7 Hz.

Cms: 81.5 Um/N

Mms: 457.5 g

However, when i enter Cms and Mms into Winisd it automatically calculates Fs as 26.06 Hz. I'm not sure how this discrepancy will affect the box design. I've seen differences of like around 1 Hz but not this big a difference so i'm not sure how to proceed.

Unfortunately, what this means is one of those parameters is wrong.

Instead of entering in the CMS, try leaving it blank and putting in the VAS. They both are measurements of the same thing, so see if that gives you an Fs that's closer to what they have listed.

ETA: You have to enter in the Sd as well as the VAS. I just tried it and it came back with 29 Hz. It might be worth a call to American Bass.

[certifiedquality]

I tried again but this time entering Fs and mms manually along with Sd and WinISD calculated VAS and Cms and these were different from the listed parameters.

Found this in WinIsd's documentation:

" Since Vas depends on current air properties, there is no absolutely "correct" Vas value existing. So every time you'll adjust your room temperature, air properties will change, and your Vas will be different. My advice is to avoid entering Vas whenever possible."

So i'm ok with the discrepancy in VAS and Cms is proportional to VAS so this would be different also. I then tried the same box design using the old parameters i had entered first and compared it with the same box design using these new values of Fs, vas and Cms and the response graphs were extremely close.

[certifiedquality]

Here is the design i came up with:

[Triticum Agricolam]

Looks good to me!