As my question implies, I have an amplifier rated as 2 x 100 watts and am using it to power two speakers with the following specifications:

  • 180 watts max and 90 watts RMS power handling per pair (4 ohms)
  • 80 Hz to 20 kHz frequency response
  • 89 dB sensitivity

The amplifier's specifications are:

  • 100 watts max power output X 2 (4 ohms, 20 Hz - 20 kHz, 0.04% THD)
  • 24V power supply - can drive 200 watts (8 ohms), 300 watts (4 ohms) speakers

I don't know much about power but wonder if the amplifier's output max limit is the 200 watts, or if the amplifier outputs more than its rating because I am using speaker of greater power.

I am also curious about this because I will use a battery to power my sound contraption, so perhaps this is a power consumption question? Could it be, how much power will the amplifier consume when powering these two speakers?

I welcome any feedback on how to improve my question. Thanks.

  • This is not a sound design question, it is an electronic engineering question, but doesn't contain sufficient detail to answer.
    – Tetsujin
    Dec 31, 2021 at 11:34
  • I’m voting to close this question because this is not a sound design question.
    – ghellquist
    Dec 31, 2021 at 13:06
  • @Tetsujin Please tell me what other details I can include. I'll be happy to follow through Dec 31, 2021 at 20:59
  • difference in interpretation of what constitutes "sound design" as opposed to "audio design". Good question, but unfortunately wrong stack I think. Migrate to electrical?
    – Mark
    Jan 1, 2022 at 4:58
  • I’ll leave formally answering to @ghellquist and others, but two points of clarification. 1) speakers rated for 160 watts peak power handling do not require 160 watts, just can handle it. 2) Amplifiers do not put out more power than they are rated for (assuming they are rated accurately) given a load they’re intended to handle: if the speakers’ could handle 300 watts of peak power, it wouldn’t make a difference at all.
    – J0e3gan
    Jan 4, 2022 at 8:50

1 Answer 1


There is a bit of misunderstanding here. The amplifier specification is a maximum power output - ie 2 x 100 W or less. The loudspeaker specification is a maximum allowed power input 160W or less -- more and the speaker will be damaged. So from this it seems like a good match.

How much power the amplifier will consume depends on how high you turn the volume - higher volume more power consumed. So no answer.

--- Addition to answer given below. So, given the specifications and nothing else we can deduce the following.

.1 The speakers can take a maximum of some power before they break apart. I believe you say a maximum of 90 W per speaker. That they are 4 Ohm is a piece of information. There sensitivity is given as 89dB with one watt of input. If you input more power to the speakers they will sound louder until you put in too much power when they will start breaking. The specs seems to indicate a "consumer type" equipment and, well, the producers tend to be a bit "happy" with specifications so you do not really know. This especially with the frequency range 80-20kHz really should include some specification at which point they measure, say at -3dB. My guess is that the speakers does not output very much bass and that the very top end, which people does not hear anyway, does not come out. Well, you use what you have.

.2 The amplifier can output some maximum power before the output gets distorted. Absolute maximum can often be a bit more. But again "consumer type" equipment often has a bit of "happniness" in how specifications are measured so you cannot really tell. And again no specification of at what level of distortion they specify the output. But it says a maximum of 100W output in 4 Ohms load (which you have) before starting to distort. So my guess is that the amp outputs a good amount of power. Not amazing specs but in the real world, the important part of a system is often the speakers anyway.

.3 So speakers and amplifier seems to be pretty well mixed together. You will not get any "disco loudness" from the combination but it may be what you want. Generally what you want to look out for is when the amp starts to distort -- in my experience it usually kills the hi frequency drivers in the speaker. Often not very expensive to get spares.

.4 Now for power input to the amplifier. It should be obvious that you cannot create energy in the amplifier. Some of the energy goes to the speakers, some goes up into heat. The amplifier will use a bit of energy when idle, not playing any sound. This could be a few watts. And then the conversion is not 100% effective. Class D amplifiers are more efficient compared to class A/B, but again the specs does not say which type we have here. But in order to output 200 Watts (2x100W) my guess is that you have to input something like 250W which then would be a max power input. But again, at typical listening levels you output only a few watts to the speakers so it might require say 10W in. It all depends.

In conclusion: neither the speakers nor the amplifier seems to have very detailed specifications which suggests to me that they are "consumer type" equipment. Nothing wrong really, it all depends on where and how you are planning to use them. They will probably work good enough for a beach party. Only way to find out is to test them.

  • The amp's output power will also vary according to speaker load. We have no nominal load figures, nor even any indication if this is true RMS or 'advertiser's peak'. There's simply not enough info to go on.
    – Tetsujin
    Dec 31, 2021 at 14:17
  • I've added the technical specifications I found in the speaker's vendor website. Perhaps the answer is different now? Dec 31, 2021 at 21:22

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