Music in the Round

I took the second option, and inserted the DSpeaker AntiMode 2.0 between the Yamaha and the subwoofers, set up as "Stereo Subs" to maintain the distinction between the "Front+Rear" subs established by the Yamaha. When I ran AntiMode's automatic correction routine (fig.2), the resulting sound was so good that I bit the bullet and ran XTZPro to develop correction filters for each sub, which I then copied into the filter set already arrived at by YPAO.

The effect of either operation was substantial, and evident with Music for Brass and Organ, a recent 5.0-channel SACD of music by Gabrieli from the Berlin Brass, conducted by Lucas Vis and recorded in the reverberant space of the Berliner Dom cathedral (Pentatone PTC 5186 509). Comparing YPAO-Natural with no EQ, the positioning and tonality of the instruments were improved and stable with YPAO-Natural but still bathed in an overripe ambience that obscured their low end and, unsurprisingly, the contribution of organist Andreas Sieling. Adding proper subwoofer EQ brought all the low bass up to the level of quality of the rest of the audioband by clarifying the reverberations, which, while still substantial, were now coherent, and not swamped by the resonances they induced in my room. The organ notes were now discrete, more solid, and quite powerful. It was possible to hear what sounded like music being performed in a real space without it being obscured by the acoustics. This sub EQ also made a significant improvement with movies and other sources.

That's not to say that the CX-A5000 with YPAO active was not up to snuff, or that, with other challenging recordings, the additional LF EQ was valuable if not essential. With Daniel Barenboim and the La Scala orchestra and chorus's spectacular 5.1-channel recording of Verdi's Requiem (BD, Decca 074 3808), I was thrilled with the open acoustic, the detailed instrument voicing (particularly of the brasses and winds), and the silken string tones. The four formidable solo voices (Anja Harteros, Elina Garança, Jonas Kaufmann, René Pape) were, appropriately, a bit forward but quite natural. The extreme bottom of the bass drum in the Dies Irae and the double basses at "Mors stupebit," in the Tuba Mirum were full and balanced. Here, adding the supportive subwoofer EQ added more impact and definition to an already strong low end. Icing on the cake.

My experience with that Blu-ray of Verdi's Requiem brings me back to the essentials of the Yamaha CX-A5000. Regardless of what source I played, the sound was spacious and clean, with a detailed but natural treble that I hear from only the best components, or live. These were characteristics, too, of the sound from streamed files, and from Internet radio via the CX-A5000's excellent and reliable Net Radio function, even with relatively low-resolution MP3 stations.

Compared to the popular Marantz AV8801 ($3599), the CX-A5000 seemed to extract more information from the upper midrange and treble—and set to YPAO-Natural, it did so while maintaining an extremely satisfying spectral balance. The Marantz does offer somewhat better rendition of the low end, no doubt due to the ability of Audyssey MultEQ XT32 to control that region of the audioband all the way down. However, if one complements the Yamaha's excellent treble and mids with additional bass EQ, that problem completely disappears, and choosing between it and the Marantz becomes very difficult. I found the Yamaha CX-A5000's pure and natural treble completely addicting, and something rarely found for $3000. Once heard, many listeners will pounce on this excellent preamplifier-processor.

Yamaha Aventage MX-A5000 power amplifier
Along with the Aventage CX-A5000, Yamaha sent along its matching power amplifier, the Aventage MX-A5000, at its precisely matching price of $2999.95. At 17 1/8" (440mm) W by 8¼" (210mm) H by 18 1/8" (465mm) D, the MX-A5000 is a massive block of an 11-channel amp rated at 170Wpc into 6 ohms or 150Wpc into 8 ohms, both specs at 0.06% THD, 20Hz–20kHz, but with just two channels driven. Switchable RCA and XLR inputs are provided for every channel, and the MX-A5000 comes with shorting plugs for the RCAs. In general, I don't find power amps to be an exciting prospect for review; as far as I can tell, a competent amp well matched to the application and other equipment will make only a small difference in a system's sound.

However, the MX-A5000 offers remarkable flexibility, and may appeal not only to those with 11-channel systems, but also to owners of bi- and triamped systems, as well as those who need additional channels for other zones or systems. So while I was able to use only five of its channels in my system, the MX-A5000 provides rear-panel Channel Select switches that, when used with the Speakers A/B buttons on its front panel, can reroute many of its inputs to more than one output. These switching/rerouting options permit such configurations as five-channel biamping, five main channels with two independently amplified zones, a triamped center channel in a mono- or biamped five-channel system, and other, more specialized arrangements. Readers with such needs will immediately see the opportunities.

I'd thought that the CX-A5000 pre-pro was a bear—but when it came to wrestling the MX-A5000 into my system, I was happy I had space on the floor and didn't have to lift onto a shelf its 56 lbs (25.5kg). The amp is powered by a single, substantial toroidal transformer placed toward the front of the case and visible through openings in the cover. Still, the distribution of weight led me to believe that the heatsinks for the output stages, not visible but presumably at the rear, are generous. Indeed, when playing loudly through five channels, the MX-A5000 ran cool to the touch. I do wonder, however, if its aggregate power output might be limited by the use of a single power transformer; although Yamaha gives impressive output specs for a single channel—230W into 6 ohms or 190W into 8 ohms, both 0.9% THD at 1kHz— none are offered for operation of more than two channels simultaneously.

The front panel has only the two small Speakers A/B buttons (for two of the channels), and a large central power button with an illuminated indicator ring. The rear panel is almost completely occupied by connectors: the 11 sets of RCA and XLR inputs at the center, each set with its Balanced/Unbalanced switch, and six with Channel Selector switches as well. The input bay is flanked by columns of multiway speaker terminals: seven pairs on the left as you face the rear panel, six pairs on the right. Between the left column of these and the inputs are the trigger in/outs and the Impedance Selector—4, 6, and 8 ohm options are provided—and Auto Power Standby switches, and below the inputs is the AC power inlet. There is an underlying logic to these arrangements, although the wide range of options does demand reading all the diagrams and taking care in attaching cables to the densely packed speaker terminals. I recommend using banana plugs; I didn't, and it would have made my job easier and more secure.

I inserted the MX-A5000 into the system in place of my Bryston 9B-SST five-channel amp and, as expected, it made little difference in the sound, which remained excellent with a wide variety of music. However, as I listened more, I found that the MX-A5000 was a touch soft in the treble—which made it a great complement to the CX-A5000. It didn't change my assessment of the Aventage pre-pro's lovely treble, but brought it subtly closer to the sound of the very best and most costly pre-pros I've used. The prickly edges of the brass in the Verdi Requiem BD were just barely less aggressive and, if possible, even more thrilling. The CX-A5000's midrange definition and bass solidity remained impressive. On the other hand, the sound of the MX-A5000 in tandem with the Marantz AV8801 was unremarkable. Some might describe the sound of this combo as being more forgiving, but if so, it was at the cost of a few goose bumps.

Power and dynamic control at both extremes were quite well managed by the MX-A5000, which made it suitable for all music sources with my Paradigm Studio/60 v.3 speakers. I felt no significant constraints with my 5.2-channel system when listening to music (no movie-sourced explosions), but despite my wife's infrequent comments, I don't usually demand the extraordinary output levels that some users do. All the while, the MX-A5000 provided as seamless, open, and balanced a wrap of sound from multiple sources as I could want.

In sum, the Yamaha Aventage MX-A5000 is a very clean-sounding, adaptable power amp. It filled all my needs for multichannel music and—no surprise—was a superb complement to Yamaha's Aventage CX-A5000 preamplifier-processor. If you need 11 channels, regardless of how you choose to use them, I strongly recommend it.

Next Time in the Round
I'll discuss the Krell Foundation pre-pro, which has at last arrived. Also, with the rising interest in streaming and file-based music, I will have a review, long delayed due to my own technical problems, of Dirac Research's Live Room Correction Suite, a multichannel software system for measuring and equalizing rooms and systems.