Not enough sub output can i add one more sub?

The subwoofer is much more than just another bass unit and the purpose is to reproduce sub-audible content in order to add ambience to the listening experience and before it can reproduce the sound it must first be part of the recording or performance. Even if a recording is rich in sub-audible content, unless the amplifier is designed to process and filter sub-audible frequencies, the amount of content available at the output is likely to be minimal.

A pair of good 3-way loudspeakers will, most of the time produce a purer and more realistic sound with plenty of power and render a subwoofer superfluous.

The fact your amp doesn't have an output for a sub means, even if you successfully connect it there is unlikely to be much activity from it.
The only sensible way to connect it would be as a ghost speaker as used by many hi-fi enthusiasts since the introduction of stereo.

The purpose of a ghost speaker is to fill a gap between the channels and is driven by the difference in emf between the loudspeaker positive of each channel. Unfortunately the difference between the channels isn't great enough to drive a loudspeaker so another amplifier will be needed.
As it is a surplus subwoofer you are trying to find a use for you should either obtain the signal from the bass unit of each speaker or use a crossover type filter in the output of the second amp.

There are several methods, depending on the the types of 1)inputs on the subwoofer and 2) outputs on the amplifier (aka receiver). You can only use the type that is on BOTH.

Most sub woofers have "line level" inputs (they are the RCA phono style jacks or other style jack) that are marked "In" or "Input" and may have speaker level input & output terminal that accept speaker wires.

Amplifiers or "amp" all have speaker level outputs and many also have jacks that are labeled "Subwoofer" or "LFE" (low frequency effects) Output. If both your sub and amp have the "line level" jacks, then all you need to do is get a cable that is long enough to connect the two together, and then enable the low frequencies to be sent to the sub instead of the normal speakers in the receiver's set up menu. Done!

If you have only a speaker level connections common to both the sub and amp, you'll most likely need to disconnect the Main front L and R speakers from the amp and connect to the sub's Speaker Output terminals - and connect a couple of new speaker cables between the sub's Speaker Input terminals and the amp's Main front L and R terminals.

If you don't understand completely, provide the make and model of the amp and the sub, and I'll be able to clear up anything that isn't clear.

The easiest thing to do is add an outboard crossover; something like a Rane AC 22S. Set the mode for stereo 2-way & mono sub out. L & R mains out from the mixer to the crossover, mono sub out to the sub and high out's to the full-range speakers.

You would need to use a modern equalizer like the EQ901 PS which has a built in crossover and four outputs. This would be connected in the pre-out / main-in loop of your Marantz 2285B.

Make sure that the level is set high enough to be audible either by the volume control on the sub and/or the sub/lfe level on the setup menu. Then make sure that you also have surround sound output selected in the blu ray player setup menu.

Hello hembreegerry,

If you like a lot of bass, you definitely need to consider another amp. The SP2X-300 is only rated at 170 watts RMS into 4 ohms mono. That would barely be enough to power one small sub. You do not specify what brand and model your subs are, their impedance, or their power handling capacity. But for any subs, your best power solution is to add together the individual RMS power handling capacity and select a monoblock amp that provides close to the maximum at the impedance they will be wired to present. For example, if your subs are 4 ohms and have a maximum RMS of 250 watts, you would want an amp that outputs abour 500 watts into 2 ohms (2 4 ohm subs wired in parallel = 2 ohm load). An ideal amp in that example would be the Alpine MRP-M500 which outputs 500 watts RMS into 2 ohms.

Hope this helps.

Hello 76firebirdfo,

If there's no sound at all from the subs and you know they are good, there's probably no output from the amp. It's either wired incorrectly or it is defective.

If there's some sound but just not loud enough, then either the amp is not getting enough of an input signal from your head unit, or the amp settings are not adjusted properly. Adjust the crossover and gains for the best output to subs. LP filter on, crossover frequency at about 80-100Hz, and gain to maximum without distortion when head unit volume is at about 3/4 maximum.

Hope this helps.

According to the specs for the xo 1945- the output is; 50W x 4 Max Power Output , and I do not see a pre amp output listed. So I think to connect subs, you will need a separate AMP.
The way this works; the rear speaker wires from the xo 1945 hook into the Add-on amp, for example a 4 channel amp. In a 4 channel amp, the rear speakers come off two of the channels of the add-on, and the subs come off the other two channels. There is also the option of bridging two channels for more output power to ONE sub.
You did not mention what size sub(s) you were thinking of adding, but keep in mind that the ox 1945 puts 50 watts MAX per channel. So, if you add two 12" subs and a 1500 watt amp to drive them, your total sound is going to be very uneven.
If you go on line and look up auto audio or amps, you'll get a good idea of all the Sub and amp options that are available.... Hope this helps.

Well make sure you have enough power wire, remote wire, RCA's make sure they are long enough as well. Now depending on wattage the amp can kick out determins on the power wire size. Run a wire bout a foot from the battery + terminal and add a in-line fuse (once again depends on the power of the amp) now run the rest of the power wire to the back. (along with the remote wire and RCA's) Now hook up your RCA's on the sub output, (If no sub output hook up to the rear) this will connect to your amp RCA's input. Now for the remote wire, wire it up to the BLUE remote wire or power intena, this will go to your remote terminal on the amp. from thier all thats left is your speaker... Hope this was helpful

The easiest solution to use your subwoofer is to buy an amp for it. Any old stereo receiver from a garage sale will probably do just fine.

1. Connect the mono RCA subwoofer output from your Sony with a 1xRCA-to-2xRCA splitter to both the left and right input of the cheap reciever's tape or aux input
   
2. connect both speaker outputs of the cheap reciever to the speaker input on your subwoofer. make sure both black (-) outputs on the reciever connect to the black input on the sub, and the red outputs (+) on the reciever are both connected to the red input on the subwoofer.
3. make sure the cheap receiver's volume is all the way down. turn your Sony up to about the loudest you'll listen to it. turn up the subwoofer amp until it's loud enough to sound good.
4. leave the subwoofer amp alone, the Sony volume will all you ever need to touch from now on.

You can even now turn off your subwoofer / adjust the volume easily now!