I recently rebuilt an older 2x15 cabinet and have been using them in that.

For the SBB4 alignment, WinISD seems to call for 2.570 cu-ft, tuned to 35hz.

Now that would be one seriously-small cabinet, even with a bunch of internal bracing, etc.

Ive seen a few cabinets that used these drivers, and none were anywhere near that small.

Ive seen recommendations for boxes in about the 4.0 cu-ft size, but no real information as to why.

When I rebuilt my cabinet, my internal volume was about 4.2 cu-ft, and I tuned to 40hz.

It was suggested (discussions in this forum) that this arrangement was not ideal for these drivers, but I was in a needful situation with less-than-optimum resources.

How many of you would follow WinISDs recommendation for volumetuning, and why Would I get a tighter bass response A more effiicient cab Thanks alot for your opinions.

Mag.

Before making your final decision change the tuning to 50hz to get more usable low end.

If you like that I would suggest the small 2.5cu.

If you want more low end then I would suggest 4 cu.ft.

You will notice that the bigger box and lower tuning will increase low end response at the expense of power handling and group delay.

You should also realise that when you add bass from your amp you are also incresing group delay and decreasing power handling.

You can verify this by adding parametreic EQ under the EQfilter tab.

That means if you want more low end from the smaller cab you will nullify the advantages the small box has.

For reference the Avatar B115 has an internal volume of about 3.6 cu.

Each compartment has two 3 ports, the top one has a Foster horn too.

I still havent really got a grip on WinISDs graphs and what everything means.

Its hard to take that information and figure out how that applies to how a cabinet will sound.

When I was rebuilding this cab, I finally gave up and just decided on a tuning of 40hz for the internal volumes I had to work with, and only because I play 4 string and 40 is pretty much the low E.

With WinISD, any cab volume above the suggested 2.5 seems to have negative results on everything.

Sure, by the time all the internal bracing and driver displacement gets taken off, it would be closer to the 2.5 cu-ft.

As a crosscheck try going to Search for the speaker and they will usually have Project Ideas with a suggested cabinet design.

The fine tuning is up to you and you will find that the popular ones are right for some drivers and not for others.

What Is An Sbb4 Subwoofer Box Look Like