Nice graph, and in case you use single cabs it makes sence. What this grap doesn't show us however, is that four 20" single loaded t60's without boundary loading will play near flat down to 50Hz and then roll off 6dB/oct. down to an Fc of 27Hz. It's a different animal. T48' will start to roll off higher at 65Hz and will do so, much steeper then t60's.
Really? Quoted from Bill on the T60 SPL forum thread:
Bill Fitzmaurice wrote:
Tuba 60 1x15 and T48 1x15, 36 inches wide:
T60 has the advantage below 32Hz, T48 the advantage above 32Hz. If you don't really need the output below 32Hz that T60 is capable of you don't need the T60, so be well sure of it before you make your choice.
Both cabinets will gain +6dB for double the cab count, only the T48 gains another +3dB from a V-plate.
Taking the natural rolloff for granted you will not have any problems with the titan48 but everything below say 50Hz will be lacking.
Please show where you see that? While a single cab starts
to roll off at 60Hz, the T60 single 20" wide has a -6dB drop starting at 48Hz to 35Hz, where the T48 beats it. While I agree that the T60 goes about 10Hz lower (T60 High pass = 23Hz, T48 high pass = 30Hz), the T48 goes a LOT louder, and benefits from the V-plate, which is especially helpful outdoors. This is why I will always recommend T48 over T30/45, because it kicks their collective ass, especially in groups of 4 or more. There are very, very few mobile operations that need
T60s, but their egos talk them into it. T48 certainly do not lack below 50Hz, in fact, they rule even the T60 down to 32Hz!
Thanks for all the input.
I'll go with the T48s at 24 inches wide. It seems that they will allow more configuration options as far placement/stacking and according to the plans can be high passed at 35Hz with 4 or more.
I also started two DR250s this weekend and so far I have the horns glued up. Spent a lot of time staring at the sketchup model to verify all the angles. I'll start a separate build thread for those later.
+100! If you can build 1 set wider, do! Can't wait for the DR250 thread, although this T48 hasn't started yet, either!