Hi all, Just thought I'd share a method I've discovered for creating testtone CDs with Dolby Digital and DTS surround multichannel tones allowed. Basically it involves creating the various tones/pink noise etc. that you want as a WAV file, and then converting up to 6 mono wave files into a single Dolby Digital or DTS WAV file. These encoded wavs are basically an AC3 or DTS stream, padded out to correct for bitrate, and written with the correct header to an Audio CDR(W). You play them on a standard dvd player or cd player with optical out, and your receiver SHOULD pick up the stream as the appropriate type and decode as if it was a DVD. You must be careful about volume, as if your receiver doesn't pick up the stream correctly, you'll get 0dB noise output - not nice for speakers or ears! Too encode, you can use SoftEncode for DD and SurCode for DTS. A free option is available with BeSweet for DD, but no free option for DTS encoding, other than obtaining it via a dodgy download. This enables you to test your bass management to the extreme, by putting test tones and MLS signals in any of the channels including the .1 LFE channel, and seeing how it directed etc. I will over the next week or so performing frequency analysis using MLS signals to see what is happening to the management of bass in my NAD T752. Hope this helps someone!