The speakers are rated as "Recommended amplifier power 50W - 120W into 8Ω on unclipped programme." That means 120W on typical musical material. Typical musical material has much lower energy levels at treble frequencies than at lower frequencies. Therefore the 120W rating applies only to the low frequency driver, especially in view of the relatively high crossover frequency (4kHz).
Tweeter power handling capability is usually far less than woofer power handling capability. However, speaker damage occurs most frequently as a result of high volume bass peaks causing the amplifier to clip. The clipped waveform contains high frequency spectral components that are not present in the original music waveform, and the speaker's crossover routes that extraneous high frequency energy to the tweeter, causing it to have to handle more power than a music waveform would normally require it to.
None of that will change as a result of the bi-amping scheme you propose, apart from a probably inconsequential reduction in the amount of current each amplifier channel will be required to supply. And keep in mind that the power delivered to the speaker is determined not by the amplifier power, but by the music and by the volume control setting (as long as the amplifier's voltage and current capabilities are not exceeded).
HiFiTime -- Respectfully, I don't think that is true. The impedance that the speaker has at low frequencies (below the crossover region) will be the same regardless of whether or not the tweeter and its crossover elements are connected. Likewise the impedance at high frequencies (above the crossover region) will be the same regardless of whether or not the woofer and its crossover elements are connected.
Regards,
-- Al
Tweeter power handling capability is usually far less than woofer power handling capability. However, speaker damage occurs most frequently as a result of high volume bass peaks causing the amplifier to clip. The clipped waveform contains high frequency spectral components that are not present in the original music waveform, and the speaker's crossover routes that extraneous high frequency energy to the tweeter, causing it to have to handle more power than a music waveform would normally require it to.
None of that will change as a result of the bi-amping scheme you propose, apart from a probably inconsequential reduction in the amount of current each amplifier channel will be required to supply. And keep in mind that the power delivered to the speaker is determined not by the amplifier power, but by the music and by the volume control setting (as long as the amplifier's voltage and current capabilities are not exceeded).
HiFiTime -- Respectfully, I don't think that is true. The impedance that the speaker has at low frequencies (below the crossover region) will be the same regardless of whether or not the tweeter and its crossover elements are connected. Likewise the impedance at high frequencies (above the crossover region) will be the same regardless of whether or not the woofer and its crossover elements are connected.
Regards,
-- Al