Currently I’m running 2 subs in my HT. I’d like to run 4. Right now I have the single line level (LFE) output on the amp split and running the divided signal to the two subs. My question is right now I notice what I think is a reduction in bass output when I split it once. Is it actually a reduction in bass output from splitting the output on the amp or is it just wave cancellation in the room? Is there any way I can test the signal level on the sub out from the amp?
this is the real cause of global warming. Soon the sun will go supernova unless you stop it.
the sub "hears" the voltage, which is not divided in a parallel connection. Assuming the subs have reasonably high input impedances, there is so little current demand that splitting cannot cause a real problem with, probably, any reasonable number of subs a person could actually fit into a room. At 2 volts (high for a receiver's sub output) into 20,000 ohms (low to middling for an input stage - I don't think a megohm - 1,000,000 ohms, is unheard of) the receiver is being focred, FORCED, I say, to put out 0.0002 watts. Yes! Fully two thousandths of a watt. And one thousandth of an amp. Put two of those subs in parallel and the power demand skyrockets to .0004 watts. Fully .0002 amps. Just not a problem
the sub "hears" the voltage, which is not divided in a parallel connection. Assuming the subs have reasonably high input impedances, there is so little current demand that splitting cannot cause a real problem with, probably, any reasonable number of subs a person could actually fit into a room.
The Laws of Physics aren't swayed by opinion.
I have noticed a drop in preamp output when Y-jacking on two different systems. I think when you do that the inputs have weird interactions with each other too. The best way is to have active buffers between each sub that isolate the inputs, kind of like a headphone amplifier with multiple outputs. If you have one of those lying around you can use it instead of splitters to see if the problem is still there or not. The cheaper headphone amps tend to be a bit noisey but it shouldn't matter that much on the low end.
The difference Aiui is that phones are passive and powered subs are not. I have over time taken plenty of heat around here from folks who do not grok this distinction in the opposite direction. Different cables can result in measurable and audible differences when they are connecting say a high output impedance guitar pickup to a guitar amp. Shifts the resonant frequency of the system. It's why Hendrix liked coiled guitar cables with his post-CBS neutered strat pickups. Rolled off some highs. Irrelevant unless something is terribly wrong in the context of a relatively low output impedance preamp out into a high input impedance sub amp.
Wouldn't the signal load change from all of the different input impedances combining in parallel? So if the number drops and there is a dc blocking cap on the amp's input for example, it would create an RC filter with a faster rolloff down low, right? I'm not saying that's what happens every time but it is one possibility where there would be degradation. I just don't see hooking 19 subs up to one jack being an audiofile kind of thing to do.
I just don't see hooking 19 subs up to one jack being an audiofile kind of thing to do.[/quote]Hyperbole doesn't help. No one suggested that. But splitting a signal to two (or even four) sub or power amps, will not cause a drop in level, nor provide any real issue in almost all cases.
As for audiophiles, they do lots of stupid stuff and generally don't understand any electrical theory, so it not 'seeming audiophile' is a positive.
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Your emotional response to the situation is your problem and it seems that you can't bear to be questioned. I'm more than happy to be proven wrong and learn something, but have yet to see anything from you that I can learn from on this subject.
Image is from the TI datasheet. Note the 1-2V region which is what most power amps need to drive them to full output. None of the distortion there is audible. This easily fulfils the OP's requirement of 4 units in parallel and I'd put money on being able to do 10 in parallel with not much worse, and certainly not audible performance.
I did not say that, I am saying I ran 8 subs on one lfe output with no problems and I measured my output and THD to be very low.