I recently started a project to build an inexpensive speaker/amplifier that is portable enough to take outside easily. I purchased a center-channel speaker from a thrift store for $6 and an amplifier for $25. I would like to combine the left and right channels so that both channels are represented in the output, but I've read conflicting information about whether this will damage the amp and/or speaker if I do it at the speaker level.

Right now I just have an RCA y-adapter to combine it at the line level (which works fine), but I was thinking it might work better to combine it at the speaker level so I can get more volume. The amp pushes out 20 watts per channel, and the speaker can handle much more than 40 watts.

Is it safe to combine the inputs at the speaker level? Can I do it without much additional expense?

  • \$\begingroup\$ What do you mean with "at the speaker level"? If you use the splitter, the power output of the amplifier is still 20W/ch so they will combine (it's not exactly a sum, unless they have different frequency) \$\endgroup\$
    – clabacchio
    Mar 19 '12 at 15:30
  • \$\begingroup\$ I am guessing he means tie the output of two different amps together. What are the amps? Do they have a bridged mode? This is starting to seem like consumer electronics hidden under the "design" term. \$\endgroup\$
    – Kellenjb
    Mar 19 '12 at 16:11
  • \$\begingroup\$ Well I don't know exactly how an amplifier works, but I made the assumption that piping the amplified signal from both channels into the same speaker would be louder than piping the output of one channel that had L/R combined prior to being amplified. Is that not right? Right now I have the stereo output of an mp3 player going into a y-adapter (that's what I meant by splitter, sorry), and that y-adapter goes into the left RCA input on the amplifier, then the left channel on the amp is the only one connected to the speaker. \$\endgroup\$
    – jdickson
    Mar 19 '12 at 19:32
  • \$\begingroup\$ @jdickson Your question is really a consumer electronics question. If you were wanting to design an amp that could be driven in stereo or mono, that would be a different question, but just using and hooking up your electronics is off-topic. \$\endgroup\$
    – Kellenjb
    Mar 19 '12 at 20:22
  • \$\begingroup\$ Sounds like you need some type of either passive or active mixer circuit. nirvis.com/mixers.htm \$\endgroup\$
    – Craig
    Mar 19 '12 at 20:55

You should not connect the two output amps together, as you will be effectively shorting them out. That may destroy them, although many amps will have protection circuitry and survive. If you want to double the output power, the best way is to buy a second speaker. Using 2 speakers will also mean that you are able to play stereo - at least, that's if you don't combine the 2 inputs.


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