together with 4 PPA12" and cross them over at 2000 Hz ? What XO frequency would be approriate ? And how many PDBT38 would balance well with the subwoofers ?
When building array be sure to stack vertically and as close to each other as possible. Like touching the frames together. As far as how many, they are 106db efficient. One would most likely work and then you may need a L pad to match to the sub. Remember a 10db increase in volume is perceived by the human ear as being Twice as loud. Now the sensitivity of PPA12 is SPL: 90.0 dB 1W/1m which means the tweeter is Twice and a half louder than those twelves. Adding more PPA 12 do not make them more efficient, it just lets them work easier and that makes them more accurate and of course can handle more power. Arrays give more ambiance and power handling. If your going to build an array why not use (270-125) they are 104 db and less than half the price.The chart below will guide you to what capacitor to use depending on the load you end up with. Be sure to series and parallel the tweeter wiring to end up with the ohms you are wanting.Hope this helpsCapacitor Value2 ohms 4 ohms 8 ohms 16 ohms1.0uF 80,000Hz*40,000Hz*20,000Hz* 10,000Hz2.2uF 36,000Hz* 18,000Hz*9,000Hz 4,500Hz3.3uF 24,000Hz* 12,000Hz 6,000Hz 3,000Hz4.7uF 16,800Hz* 8,400Hz 4,200Hz 2,100Hz6.8uF 11,600Hz 5,800Hz 2,900Hz 1,450Hz10uF 8,000Hz 4,000Hz 2,000Hz 1,000HzFrequencies marked with a (*) are effectively beyond the range of normal human hearing
Date published: 2012-05-08