I've been looking around for a single 12" cab for PA use with the following perks:
- less than 50lbs
- high power density (125db @1m half space with two cabs)
- F3 of 35Hz or lower
- passive cab
- Less than 500€/600$ total cost for DIY
- Parts available in Germany
I even had a hard time trying to find a commercial solution like this, but was planning to DIY anyways.
I decided to go with the B&C 12BG100 because of its high power handling, Xmax of 10.5mm and good performance in a small cab (and because I'm very happy with my two 21DS115's). If you know of a better driver for that application let me know!
I simulated a vented 50l cab with 35Hz tune, which gave me an F3 of just below 33Hz after dsp. Output is excursion limited, but the cab reaches 117db (1m full space in WinISD, I guess?), which would equal to 129db half space with two cabs stacked. Excellent!
There is also an efficiency (?) maximum around 60Hz, which is great since that's usually the best punchy frequency for a kick drum.
Here are the graphs and the filters applied:
Looking good to me, but as I said, this is the first time I've ever used WinISD so please point out the mistakes if I made any!
So now to my question: I have no clue about air velocity and port design, except that a flared port can reduce port noise, too much displacement can cause chuffing and that there is port compression.
Here is the air velocity graph; the port dimensions are chosen this way because I want the cab to have a slot port at the side (front firing), utilizing the full height of the cab (easier to build). 40m/s seems pretty high to me, but it's at the very bottom of what the cap will be capable of. It'll be used for some EDM DJ stuff (at weddings) occasionally, which is why I'm going for quite a 'low' tuning for music (for a 12" for PA application at least).
Also, the port seems pretty long to me with 43cm. Running the port that long would either require running it along the rear wall as well or a ~50cm deep cab, which wouldn't be that bad.
I might also increase the port dimensions and run it a little longer, as a 3cm wide port seems pretty small to me. What impact does folding the port have? Is my data correct? Does this make sense