I am looking for info on the subject of (FAST) Loudspeaker Design. I have done many searches but I think maybe the term "FAST" is getting lost in the translation of the search. I am working on a design that utilizes a 12" woofer and a small 3" full range for a 2-way design with a low (+/-500Hz) crossover point or maybe a 1st order at a higher point. I have been told this relates to a FAST design but I cannot find any info on this and do not know what the principals are. What does FAST stand for? Can anyone direct me to some pages or threads?
Any help would be greatly appreciated.
Thanks
Matthew
Any help would be greatly appreciated.
Thanks
Matthew
be careful of "1st" order highpass as an impedance peak in the driver/driver-cabinet combo combined with the cap's reactance can result in a bass "boost" which can make the higher frequency driver's excursion worse than nothing at all. It would be good to nullify the Z peak with a LCR network so it can be used with just a cap, or try to flatten it with aperiodic, or use a 2nd order highpass with low DCR choke.
Nice.
I am finding lots of good info now, thanks to you guys. This will be my first FAST project. Here are the drivers (Swan 305 and Fostex FE126) I will be trying to match up. I already have them from other projects so I wont be buying any drivers....just wood and crossover parts. I want to make it a passive crossover as well so I have something to play with. Keeping the box design a simple 2-way Bass reflex might work out ok.
I am finding lots of good info now, thanks to you guys. This will be my first FAST project. Here are the drivers (Swan 305 and Fostex FE126) I will be trying to match up. I already have them from other projects so I wont be buying any drivers....just wood and crossover parts. I want to make it a passive crossover as well so I have something to play with. Keeping the box design a simple 2-way Bass reflex might work out ok.
FE126 is a 4 1/2" FR.
It works nicely in a small sealed box for this kind of application. To take advantage of the natural 2nd order roll-off (~200 Hz) you should consider active.
dave
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I know that Dave, I don't know why I said 3". I have had this driver in a 2 liter box for a long time and it sounds quite nice. If I do a 100 liter or so bass reflex box for the Swan and incorporate a 2 liter mid-chamber for the Fostex, I think I will just install the banana inputs as driver inputs. then I will be able to build the "passive outboard" or go active.
Incidentally, following your work on this forum is one of the reasons I bought the Fostex many years ago. They sound quite nice. I have even gone so far as making several acoustic lenses for them with the stereo lithography machines I have access too. I did this to try to improve the imaging. It works to some degree in some rooms but not in others. I need more experimental time and measurements.
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