Originally Posted by pete424
First, thank you to all that took the time to respond. I wasn't suggesting that the 2 channel wireless headsets from Sennheiser were less than high quality. My thought was if I were going to go wireless, I think I would rather try the HD-220 with a surround feel. My questions have morphed to this: I purchased the Sennheiser HD-598 headphones and the sound directly from my Onkyo TX-NR-717 was just a bit anemic. Not horrible but certainly not acceptable, especially at low volumes. So I started looking for an amp. I found the Emotiva XDA-2 unit. Nice looking, good reviews and not crazy on price.
It appears to me that you are stacking one questionable choice on top of another.
Since my last post my HD 160s suffered mechanical failures, so I took my own advice - I bought a pair of HD 170s.
I learned a number of things.
(1) It appears that the HD 160, 170, 180 and and maybe even the 220 use the same dynamic transducer, basic digital radio receiver, and headphone drive circuit.
(2) The RS 160 uses this transducer without adding any equalization, while the more spendy models have adjustable bass boost. The bass boost control is a good idea. With the RS 160s I added the needed bass boost before the transmitter and then ran out of dynamic range in the digital link with a few really noisy movies because of the limited maximum acoustic output of the headphones. I find them all to be somewhat bass shy without equalization. The equalization available in the upper models seems well matched to the transducer.
(3) Headphones generally have 2 transducers and human beings have generally have 2 ears. Seems like a good match! AVRs generally matrix whatever they receive into an acceptable or better 2 channel drive for their headphone jacks. I happen to use a separate Technics surround decoder for the just the headphones so I don't have to run my AVR to listen to headphones.
(4) I expect my HD 170s to require a new headset at a cost of over $100 within a couple of years maximum because the common RS 160/170/180 etc.transducer/earpiece/headband assembly has designed-in weaknesses that a bit surprisingly result in all of the earpad mounting tabs to break off after about 18 months of really heavy use. Mine all broke off individually over a period of about 2 weeks. I continued to use the headphones by means of the application of several pieces 2-sided adhesive tape per headcup. I admit it - I use mine for several hours every day and even fall asleep while wearing them. The falling asleep part is probably especially bad. I have acquired over a dozen pair of different high quality headphones over the years, but only one other pair have fallen apart this way despite even longer periods of use. BTW, the other ones that broke weren't the RS 120s that I had before these. Those were replaced on the grounds of sound quality but they appeared to be more durable.
(5) The RS 170 has about twice the range of the RS 160 and it is finally barely adequate. No way do I get reception over 180 feet. Maybe 50 feet at best. My house does have exceptionally heavy construction including steel beams in the walls and ceilings and wet plaster.
(6) I use a 30 band graphic equalizer to customize the sound of my headphones.
(7) None of these headphones are what you'd call really loud, probably because of European laws relating to headphone maximum acoustic output.
(8) I remain unimpressed by the surround features.
(9) Everyhing I listen to goes through my TV set which has an optical stereo output which I use to drive the surround decoder for the headphones. I believe that the FIIO D07 driving a FIIO E5 for a total cost of about $70 would do a great job of driving just about any heaphones. The E5 is not needed for digital headphones because they have a high input impedance and are compatible with the D07. The D07 handles both stereo and mulitchannel optical and coaxial inputs for about $50.