The impedance of current Sound Lab models, namely the PX series, is being measured by Roger West at this time. I requested it since we are looking at a large installation which may involve driving more than one speaker from an amplifier, possibly Atma-Sphere. When the impedance curves are developed I will try to make them available.
Amplifier power output ratings are nominal only, especially when driving difficult loads. I have had 100 watt amps drive the U-1s here well, while 250 watt amps fell flat on their faces. Interestingly, both were tube amps with output transformers. The speaker load is a challenge for any amplifier, whether tube or solid state. Amps with robust power supplies tend to do better. Not all OTLs are necessarily well suited to drive big ESLs like Sound Labs, either.
Disclaimer: I'm a Sound Lab and Atma-Sphere dealer.
Brian
Amplifier power output ratings are nominal only, especially when driving difficult loads. I have had 100 watt amps drive the U-1s here well, while 250 watt amps fell flat on their faces. Interestingly, both were tube amps with output transformers. The speaker load is a challenge for any amplifier, whether tube or solid state. Amps with robust power supplies tend to do better. Not all OTLs are necessarily well suited to drive big ESLs like Sound Labs, either.
Disclaimer: I'm a Sound Lab and Atma-Sphere dealer.
Brian