we have an open project which is about building a device with logical kernel which is able to measure an amplifier (SS or tube or Hybrid) characteristics like frequency response with given tolerance, THD, 2nd, 3rd harmonics, rise time and settle time, output impedance,... all with high accuracy...

I go for cross country biking now and then, so I'm looking for a good neckback headphone. I got access to Sennheiser models but have no idea which one is the best from sound reproduction point of view. any help is much appreciated.