What Instrument would you listen to?

Theo, Beethoven's Waldstein sonata is my favorite of the 32 sonatas he wrote. Also, it is a great piece for equipment audition. Very dynamic and engaging. You can listen to it 1000 times and not tire of it, which can be helpful when you are auditioning equipment.
I like to use good recordings of recent vintage for auditions. The Schiff account on ECM of this sonata is a pretty decent recording. Not sure if he used a Steinway or Bosendorfer grand for the Walstein. The Paul Lewis recording of this sonata is also probably very good, but I haven't heard it yet.

Brownsfan, if you don't already have it try to find the 1981 recording on the Astree label of Paul Badura-Skoda performing the "Waldstein" and two other Beethoven Sonatas on an early 1800's fortepiano. I have it on LP as Astree AS73. Not sure if it was ever released on CD. An absolute treasure, musically and sonically!

Best regards,
-- Al

Brownsfan, I did find it on Amazon on the ECM lable and am ordering it once I get my order completed, I realize that it was ONE selection you suggested not two as I said. I did see a number of other listings but am sticking with your suggestion, I have been realy wanting to get a good piano recoding for evaluation as well as enjoyment.
Again thank you for your help.

I find, when the cymbals sound right, the highs fall into place, but that is it for these ears. A Bosendorpher piano (sp?) is the piano I want to hear. Those extra notes would certainly help clinch the deal.

My own. :)

I actually do often audition equipment with horn music, sometimes with recordings of my orchestra.

But to give a more serious answer to your question, the human voice would be the one to use, and not just sung, but also spoken. The horn is not a bad second choice, though, as it has one of the more pure timbres, acoustically speaking, among the orchestral instruments.

Some folks recommend piano because it is a difficult timbre to duplicate. If you want to try another very complex tone acoustically, than the oboe is a good choice. But if the more pure timbres are not resolved very well, then certainly the more complex ones won't be, so I would first use instruments with less complex timbres.