Speaker output from amps ?

[Audio Al]

I have been thinking of maybe running 2 pairs of the same speakers from one amp

The amp has an option to select

Speaker 1
Speaker 2

or Both 1+2

Does anyone know what the amp does when 1 + 2 are selected together ?
Doe it split the power output
Would the quality from the amp drop as it is powering 4 speakers not two :scratch:

cheers :)

[istari_knight]

You mean like on some amps it says A/B/A+B ? If so then output power is not split. The amplifiers output will be fed into a relay which distributes it to A/B/A+B for your selection.

Most if not all amplifiers with this facility state that if powering 2 pairs of speakers at the same time they should range between 8-16Ω to avoid damage to the output stage.

[Audio Al]

You mean like on some amps it says A/B/A+B ? If so then output power is not split. The amplifiers output will be fed into a relay which distributes it to A/B/A+B for your selection.

Most if not all amplifiers with this facility state that if powering 2 pairs of speakers at the same time they should range between 8-16Ω to avoid damage to the output stage.

Thanks James

[Ali Tait]

If you run two pairs at once, you are effectively running them in parallel, so the amp will see half of the total impedance, so with two pairs of 8 ohm speakers connected, the amp will see a 4 ohm load, hence the requirement for speakers that are an easy load i.e. 8 ohms or more. Many modern speakers drop to 4 ohms at some point in the frequency response, more so with more modern ported designs, so it would pay to check the impedance curves of the speakers you are going to use.

[Reffc]

If you run two pairs at once, you are effectively running them in parallel, so the amp will see half of the total impedance, so with two pairs of 8 ohm speakers connected, the amp will see a 4 ohm load, hence the requirement for speakers that are an easy load i.e. 8 ohms or more. Many modern speakers drop to 4 ohms at some point in the frequency response, more so with more modern ported designs, so it would pay to check the impedance curves of the speakers you are going to use.

Correct...it effectively means that you'll draw twice the power from the amp as compared with driving one set of speakers on its own for the same output from each set of speakers. All you need to check are the speaker specifications to make sure that you'll have ample headroom on the amp to avoid clipping. (ie if the amp is rated at 100w RMS and the speakers are 8 to 16 Ohm nominal with a reasonable sensitivity and no nasty phase envelopes, you should be fine. If the amp is lower output and the speakers are a difficult load/under 8 Ohms, you may risk over driving the amp which wont do the speakers or amp any good).