My part (Sandy Bird) here is to provide some bench measurements and add my two cents worth to the review. I wish all my reviews were so easy to complete. That said, lifting the Yamaha RX-Z1 was the most difficult part of the entire process.
For the most part my feelings echo Brian's in their entirety. The unit is the best sounding Yamaha receiver I have ever used, and I have tried many over the years. I cannot stress that point enough, since the one gripe I have with Yamaha is that their receivers tend to sound bright. The RX-Z1 is anything but that, it makes Jazz sing and Hip Hop thump, all the while maintaining a detailed smooth presentation. The unit has power beyond necessity even in reasonably large rooms. It never sounds stressed at any time, even at unlistenable levels. To me, this unit sounds every bit as good as my BK AV5000 MKII power amp.
I do not agree with Brian's comments on the remote layout (I have to disagree on some level or it would take the fun out of this). The supplied remote is a re-branded Phillips Pronto TSU-2000 with a slightly different outer shell. I have two Pronto remotes in my home and use button layouts much smaller and tighter than the ones Yamaha has chosen. At no point did I feel the need for a stylus. If anything, I think Yamaha could have put more controls on a single page. Regardless, this is a great remote and all manufacturers should now be OEM'ing a professional remote from Philips or Universal Remote Control instead of trying to design their own remotes.
The only other comment I will make on its functions, is that the RX-Z1 is almost unusable without the on-screen display. In most cases, this will not matter to users, but in my case I have to turn on a projector to make configuration changes. With the large display on the front of the RX-Z1 they could have made it easily configurable without the aid of the on-screen display. We believe Yamaha has corrected this issue with their newer receivers.
On the Bench
The RX-Z1 measures as good as it sounds. It is nice to know that when you pay close to $3,000 for a receiver, you get performance that rivals separates. All pre-out measurements are taken at 1 volt in and 1 volt out. Speaker output measurements were taken at 120 watts into 8 ohms. The unit easily dealt with its specified 130 watts, but due to the attenuation increments it was more convenient to take measurements at 120 watts. It is also interesting to note the RX-Z1 clips much softer than the RX-V640 which basically slams into a brick wall when it clips.
The graph below shows 0.01% THD+N using the S/PDIF input while taking measurements from the pre-outs. Very respectable
Using the same S/PDIF connection, the unit showed 0.0016% IMD, using 5 and 6 kHz test tones, again excellent performance.
With the CD analog input, we observed an even better 0.004% THD+N measurement.
IMD with the analog inputs is 0.002%
Frequency response is flat out beyond 40 kHz
At the power amplifier output (speaker output), you can see that at 120 watts into 8 ohms, there was only 0.01% THD+N.
IMD remained a respectable 0.0018% at 120 watts into 8 Ohms.
The frequency response at the speaker output was almost the same as with the pre-out.
All-in-all, if you can deal with the interface challenges, we think you will be 110% satisfied with the audio performance. This is a fine product at the performance level, which is really where it counts.
While this is undeniably the best sound we have every heard from any Yamaha receiver to date (and I have heard a lot of them), we are not thrilled with RX-Z1 usability. We are very much looking forward to Yamaha's first THX Certified AV Receivers which are coming to market now, as we hope that in following the THX Design manual, many of our concerns, such as time alignment and volume settings, will have been addressed by Yamaha, yielding a world class product. We formally invite Yamaha to send us one of their THX units as soon as possible so that we can put it under our critical view to see what this new cooperation between the two companies has produced.