I'm currently running 2-4 QW218 depending on event. I use a single PL380 to run them in both configurations of 2 or 4. I want to get a different amp so I can use the PL380 for other purpose. I'm considering getting an fp14000 for subs, but I want to add two more subs for larger events for a total of six QW218. If I get an fp14000 I won't have an amp for the third pair of subs.
My questions are:
What amp configuration would you recommend? I do NOT want to run amps in bridge mode. Is there an amp I could get in addition to the fp14000 to run third set of subs? Or what other amps configurations do you recommend? Also, I'm not a fan of on-board digital processing. I prefer higher quality amps, but I'm open for suggestions. I currently use all PL3 series, so equal or better quality.
I guess the real question is: do I need to maintain watts, ohm, load ratios across all subs? Or can the third set be run off a sub with different ratings as long as the subs are adequately powered?
PL380 is a good amp as you know and you could do worse than just picking up another 1 or 2 of those. Here is my advice to people:
What is the Load? Those QW218 are near the top in ability to handle power. The minimum impedance at 7.2 ohms is not too low to need to avoid paralleling them. The PL380 holds full power very well at 4 ohms, but only 80ms at 2 ohms. So you may be leaving some woofer capability unused when running 2 cabinets per side.
What is the Signal? If you are just reinforcing a Capella groups then most anything will do. But if EDM, special effects and synthesized bass are part of the mix, then you have to hold full power for a few seconds, not milliseconds or protection circuits in the amp will kick in and suck out the bass.
As others have said, most modern amps do not care if loads between the channels are matched or not. Interesting your comment about bridged amps because one case when it does matter is when you have a half bridge Class D amp that is loaded more on one channel and driven to high levels at very low frequencies you can get into a situation called power supply pumping. The back EMF from the sub can cause overvoltage of one polarity of the power supply. Modern amps detect this and protection circuits jump in to avoid blowing the outputs, but the result is a suck out of the bass right when you need it the most. The solution is to bridge the amp so that the back EMF is distributed equally to both power supply . I think 50-60ms hold time (2 cycles at 30Hz/40Hz) is the minimum hold time for rock music (thump thump thump) and 3-4 seconds for EDM (bwaaaaaaaahhhh). Steer clear of 20ms 1KHz power ratings for subs.
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