I'm currently shopping for a subwoofer to turn my 2.0 system into a 2.1 system. I was wondering what the pros/cons are between high-level speaker inputs and line-level RCA inputs are.
My amplifier is a 2 channel flea-watt tube amp. It only has 2 high-level speaker outputs. My receiver( actually a mixer ) has a couple line-level RCA outputs that could go to my amp and sub.
Option 1: Use the sub with high-level speaker inputs and outputs
Option 2: Use the sub with line-level input.
Option 3: -Maybe I'm missing an option? lol
What's the 'best' option?
The best option depends upon all of the specific gear we are talking about, and the desired outcome.
Theoretically, it is better to use line level inputs than speaker level inputs for a powered subwoofer, because otherwise, the subwoofer simply reduces the power down to about a line level and then re-amplifies it, so you get the added distortion, noise, whatever, from the main power amplifier in addition to whatever is going on in the subwoofer, without benefiting from the power being used. However, if the main amplifier is good, then this is likely to make for an inaudible difference.
There is also the issue of which devices are capable of redirecting different frequencies. With
some powered subwoofers, the line level output has the deep bass filtered out, and so one can hook up one's preamp to the subwoofer, and use the subwoofer's line level outputs to the main amplifier, thus freeing it to provide power only to the upper frequencies, so you are less likely to run out of power for them. Of course, how well that will work depends on what frequencies are filtered out of the line level output, and the capabilities of the main speakers. And, of course, not all subwoofers handle things that way.
If you have a preamp (in your case, your mixer) that has an electronic crossover in it, then using that to send the signal directly to both the power amplifier and the subwoofer (upper frequencies to main amplifier, lower to subwoofer, obviously) is likely the best approach, assuming that you want to not send the full range signal to your main speakers (which, if you need a subwoofer, you probably do not want to send the full range signal to the main speakers). You can also buy a separate electronic crossover, though some of them can be expensive (professional models tend to be much cheaper than home units). And depending on the specific gear and desired results, it may not be a good investment, as the money that goes into that could go into a better subwoofer instead. But, again depending on the specific gear and desired results, it might be an excellent investment.
