Hi ...
I'm building a subwoofer for my car, a Jeep which has space issues. I have solved the physical and audio (driver) part of the design. I could just allow the subwoofer amplifier do the filtering, but I'm considering adding more sound shaping to my subwoofer box with a low pass filter. When you research these, the general format is this: positive lead --> coil (or resistor) --> (fork) capacitor shorts to ground in parallel with the speaker driver.
1)why is there the need for the coil BEFORE the parallel fork in the circuit? Aren't you just choking off the HFs that you are right after that going to bleed off (by pass) with the capacitor?
2)why have the coil there at all? Won't the capacitor, sitting in line with the speaker, always present a load to the audio signal? For frequencies at 'x' or below (where the capacitor resistance becomes greater than the speaker's resistance), the LF signals will go through the speaker and create a load for the amp. The highs will pass through the cap with virtually no resistance, but the LF will still present a load to the amplifier.
3)is the issue protecting the amp from a below 1 ohm load? I'm going to have 2 4 ohm drivers in parallel creating a 2 ohm subwoofer. If I add a bypass cap across the positive to ground (just before the positive driver lead), will this bring the total resistance to an unstable value? Is this why you see the coils and or resistors in series before the capacitor bypass line to ground?
4)given the state of subwoofer amplifiers for cars, is the low pass circuit in the sub box overkill, and not worth the trouble and possible stupid factor in adding it?
TIA.
I'm building a subwoofer for my car, a Jeep which has space issues. I have solved the physical and audio (driver) part of the design. I could just allow the subwoofer amplifier do the filtering, but I'm considering adding more sound shaping to my subwoofer box with a low pass filter. When you research these, the general format is this: positive lead --> coil (or resistor) --> (fork) capacitor shorts to ground in parallel with the speaker driver.
1)why is there the need for the coil BEFORE the parallel fork in the circuit? Aren't you just choking off the HFs that you are right after that going to bleed off (by pass) with the capacitor?
2)why have the coil there at all? Won't the capacitor, sitting in line with the speaker, always present a load to the audio signal? For frequencies at 'x' or below (where the capacitor resistance becomes greater than the speaker's resistance), the LF signals will go through the speaker and create a load for the amp. The highs will pass through the cap with virtually no resistance, but the LF will still present a load to the amplifier.
3)is the issue protecting the amp from a below 1 ohm load? I'm going to have 2 4 ohm drivers in parallel creating a 2 ohm subwoofer. If I add a bypass cap across the positive to ground (just before the positive driver lead), will this bring the total resistance to an unstable value? Is this why you see the coils and or resistors in series before the capacitor bypass line to ground?
4)given the state of subwoofer amplifiers for cars, is the low pass circuit in the sub box overkill, and not worth the trouble and possible stupid factor in adding it?
TIA.