Can you use a receiver that has a higher wattage output than the speaker's recommended amplification?

Question

Newbie question here - If your speakers have a recommended amplification max of 150 watts per channel (@8 ohms), can you use a receiver/amp that has an output capability of 300 watts per channel (@8 ohms)? Will this send too much power to the speaker, possibly causing damage to it? Is there a way to limit the amount of wattage that the amp/receiver gives to the speakers? If so, how would this be done?

Answer 1

None of this is as straight forward as everyone would like it to be. Speaker power ratings are gross estimates at best and the actual power required to damage can vary dramatically depending on frequency, distortion etc. For example you can easily blow a "150 watt" speaker with a 50 watt amplifier given the wrong frequency and too much distortion or clipping. Sometimes having a more powerful amplifier can be less likely to damage a speaker because it is less likely to clip. It is however still possible to destroy a speaker with clean pure unclipped power if it exceeds the rating by a significant amount for a sustained period of time. Also, the ratings themselves can be pretty arbitrary. Most driver manufacturers provide a "nominal" power rating which should be a relatively good estimate of the thermal capability of the voice coil to handle continuous RMS power. Typically a speaker system manufacturer will rate a speaker about three or four times the nominal rating of the driver which is reasonable because music is very dynamic and the average power level is usually quite low relative to the dynamic peaks.



Amplifiers don't actually have an impedance such as 4 or 8 ohms. The output stage of the amplifier will be essentially zero ohms. The ohm rating in the amplifiers specifications is a description of current capacity of the amplifier expressed in ohms. They could tell you it is capable of some number of amps but you wouldn't know what to do with that. They tell you don't put speakers on it that are less than 4 ohms and you understand. You don't have to pull out a calculator and start trying to sort it all out, you just make sure your speakers are 4 ohms or greater.



You limit the amount of power to the speaker with the volume knob but again, this is not that straight forward. You might think that on a 300 watt amplifier that 1/2 volume is 150 watts and full volume is 300 watts but that's not the case. With no input, full volume is zero watts. Playing a recording of crickets chirping in the night full volume might be peaking at less than 1 watt. Playing a recording of a space shuttle launch at 1/4 volume might be clipping the amplifier (attempting to drive it beyond 300 watts). Music and movie sound tracks can be very dynamic. The power to the speaker is constantly changing from fractions of 1 watt possibly to the full 300 watts or beyond into clipping all without moving the volume knob. The volume knob is just a gain control. It determines how much the input is multiplied going to the output of the amplifier. A typical amount of gain for full volume is around +30 dB or about 1000 times. If the input is small like in the case of the soft chirping crickets multiplying by 1000 may result in less than 1 watt. If the input is large such as in the case of the shuttle launch multiplying by 10 may result in clipping.



I don't know of any receiver that is 300 watts/ch. Some may claim to be but none really are. For this you need straight power amplifiers instead of a receiver. These are available in very high power capability.



There is no way to be certain you are not playing at levels that could damage your speakers short of monitoring the voice coil temperature and observing the excursion to insure you are not mechanically over driving. Some speakers will begin to sound distorted to let you know to turn it down but I personally have fried drivers with the system still sounding great. I tend to like having a lot of power reserve so I tend to burn out drivers with clean undistorted power. Well at least I use to but now my HT uses big line arrays with so many drivers dividing the power it would be almost impossible to blow the speakers before destroying your hearing and causing structural damage to the room. If you really want to avoid speaker damage that's the way to do it, simply have so much overkill capacity that you never have to worry about it.



mk

Answer 2

Here are the basics. Generally, your amp should slightly to somewhat exceed the rated wattage of your speakers, PROVIDED THAT the ohm load is the same (PLEASE do not use 4 ohm speakers with an 8 ohm receiver). Thus, if both are 8 ohm, yes, go ahead and use that 300-watt receiver with the 150 watt speakers, but just don't turn the sound up all the way, or you'll blow the speakers. However, if you use a lower-wattage amp with higher wattage speakers, you can get an inefficient electrical load, which will result in worse sound. On the other hand, it will be technically impossible to blow the speakers in that case.

In answer to your second question, you can place a fuse in the wire between the receiver and the speaker - a fuse rated BELOW the maximum wattage that the receiver outputs. This will cause the speaker to shut off if you turn the amp up all the way. You'll blow the fuse, though, so you'll have to replace that if you do.

Answer 3

yes you can damage speakers by driving them too hard.

If they have multiple drivers (tweeter, mid-range, woofer) with a crossover unit, then the tweeter typically has a much lower power rating than the woofer based on normal music characteristics, so you can easily damage it at a lower power level with a pure frequency like from a electric guitar or synth.

Answer 4

Maniac is real. you're infrequently ever putting out a hundred and forty watts of power aside from very small bursts. in reality - for a HT equipment you place out an common of 10-12 watts according to speaker over the path of a movie. yet you're able to double the flexibility to get a million db quantity develop. using fact of this we've receivers that do a hundred+ watts according to channel - to handle the quantity swings.