MX6050D Subwoofer Issues

You don't say what make or type either of the appliances are, so I can only answer in general terms.
First look at the back of your stereo system and see if there is a dedicated subwoofer output. If there is you should be able to find the correct lead between the two units by looking at both the connections. If the subwoofer is a powered one. IE with a mains plug on it, you have to plug it into the mains before it will work at all. The connection points also then need to be hooked up to the amp. If it's not a powered subwoofer then your main left and right channels speaker wires need to be split into using the subwoofer terminals provided. Another set of terminals on the sub, then lead to the main speakers.
Lastly if it has a dedicated subwoofer output, then the amp might have a setting that turns this on or off. So you might need to switch it on.

Many subwoofers accept both line level (RCA jacks) and amplified inputs (+ and - speaker terminals). The Pioneer SX-316 does not offer line level output, only amplified outputs via the PURPLE + and - speaker terminals. This means that in order to use any subwoofer with an SX-316, the sub woofer will need to accept a + and - speaker wire connections for input Your manual speaker connections are on page 11 of the manual which can be found here: http://www.manualslib.com/manual/260358/Pioneer-Sx-316-S.html#manual

Starting at the rear of the SX-316; run a speaker wire from the PURPLE + and - terminal (SUBWOOFER) to the + and - speaker input terminals on the subwoofer. See your subwoofer manual or experiment (at your own risk) with connecting the speaker wire from the SX-316 to the subwoofer's + and - LEFT only, RIGHT only or BOTH left and right speaker inputs. Do not connect wires from the SX-316 to the speaker OUTPUT terminals of your subwoofer.

Finally, adjust any variable low pass filter knob or setting on the subwoofer to the lowest frequency that your main speakers are capable of producing. If you're not sure what that value is, try setting the subwoofer to 100Hz and judge how it blends with the main speakers. If it seems a little too bass heavy and thick then reduce the setting to 80Hz. On the other hand, if the sound seems to be slightly thin and lacking weight, try increasing the setting to 120Hz. By careful listening and a bit of patience you will be able to get the sound to seem balanced and well blended.

Good luck!

The subwoofer is normally the main power supply for the other speakers. When setting up the system, there is a set up guide which allows you to control the power supplied to each speaker. You may have inadvertently set the subwoofer to have 0 output.

This manual discusses it somewhat.

http://service.us.panasonic.com/OPERMANPDF/SAAX730.PDF

Basically, feed the self-powered (active) subwoofer from the Subwoofer Out. There does not seem to be a way to adjust the subwoofer output to match the rest of the speakers because the sub out is muted during the adjustment procedure.

Another way would be to refer to page 15. The note at the bottom right suggests your subwoofer might accept full range speaker level inputs. Refer to the manual for your sub. I believe they mis-printed it and meant "active" subwoofer, as simply wiring a passive (unpowered) sub across the front speaker outputs might cause some amplifier overload issues and you would have no way of balancing it anyway.

change the settings in your audio , it might be set to 2.1 channel which might have stopped the other three from working.

The signal don't seems to be present to the sub input.
Try change the wire betwen the audio system and the subwoofer.
Spider Guy

Unplug all of the speakers and power on.Its possible that one of the speakers is causing the protection circuit to activate.If powered on and subwoofer works start reconnecting one speaker at a time( after powered off) and retest each time.One Speaker may be bad.Its also possible the output ic is failing under a speaker load.There are no fuses related to this issue.If its not a speaker problem then the subwoofer will need to be serviced.

if this is ao powered sub, that plugs into the wall, there should be no problems, if it is powered solely by the reciever it may work fine but be sure you dont exceed amperage on the subwoofer.

Well, as I know, your Cerwin Vega subwoofer is designed for use with stereo systems. Therefore, it has only 2 channels for input, and 2 channels for output as well. However, you can try this out; the first thing I suggest is that you hook up your main front channels through the subwoofer. All you have to do is to connect the subwoofer input to the front channel output on the amp, then hook up your front speakers to the satellite output on the subwoofer. As long as you make sure that system is working on 8 ohms, I believe this can activate the subwoofer.

Most AV receivers do not have a built in amplifier block to drive a subwoofer, and merely provide the subwoofer output channel at line voltage. Thus, a powered subwoofer is required. Does the subwoofer require mains power? From your description, I'm guessing it doesn't. If not, it does not have a buit in amplifier, you will need to purchase a monoblock amplifier, which is just a mono amplifier with a volume control, no tone controls or anything else. Make sure that the amplifier power rating is as close as possible to the subwoofer power rating, as it is quite possible to blow a speaker by using an amplifier whose power output is too low, by overdriving the amplifier , and putting DC through the voice coil when the amplifier clips. If it does require mains power, it will have an amplifier built in, but does not have line level inputs.