Hope this is not high jacking the thread but I need some advice about the importance of impedance with headphones. I have used Grado 60's for 10+ years. They are great but are an open design and I am looking for something as good but more enclosed to keep out background noise. The Grados have an impedance of 32 ohms. I once bought some Sennheiser phones (cannot remember which ones) with a higher impedance and couldn't get anything like the same volume from my Yamaha piano so I took them back. Also I don't really want noise cancellation phones that take batteries.

Any comments on impedance and choice of phones, up to say $200?

Thanks
Tony