General Asylum: Re: Question: amp power and bi-amping by djk

If you use an electronic crossover and bi-amp a speaker like a Klipsch Cornwall with a 50W amp on the bass and a 10W amp on the mid and hf it will play as loud as a 400W amp through the passive crossover.If you 'bi-amp' your Newform speakers with a 250W amp on the bass and a 160W amp on the hf without an elecronic crossover it will play as loud as the 160W amp would play running both.The 4:1 benefit for bi-amping is only there when the spectrum is divided ahead of the power amps and when the division point is near the mid point of the spectral distribution of energy.On a voltage basis the division occurs around 250hz.This must be weighted by the peak to average ratio so that the equal energy point for above and below the crossover is about 500hz.This is also affected by the slope of the crossover.For the example of the Klipsch Cornwall it has a 600hz crossover point.If the drivers were the same efficency then 50W + 50W would = 200W through the passive crossover.In reality the HF is 10dB more efficent than the LF so we only need 50W + 5W to = 200W.If the HF remains undistorted it will mask distortion from the LF amp driven slightly into clipping.This means that if we use a 10W HF amp with a 50W LF amp it would take 400W to play the same level undistorted through the passive crossover.If you 'bi-amp' your Newform speakers without an electronic crossover each amp will be receiving full range signal and will clip at the same point it did with only one amp hooked up to the speakers.It does sound different to do this, but make no mistake, you will not be getting the benefits of dividing the signal ahead of the amplifiers.