Pioneer VSA-AX10Ai-S, Pioneer's beast laid bare

• Never before had Pioneer designed an amplifier as demanding in multichannel audio as in stereo. It could not be better equipped.

• Price: €4,890

• Specialists' rating: 5

• Text: Ramon Sendra

We were very keen to get our hands on the manufacturer's "top-of-the-range" receiver, especially after having had the chance to chat with some of the engineers who took part in its design. That conversation took place at AIR Studios in London, together with the very sound engineers who gave the beast its "final touch". On that occasion we only had access to the receiver with Pioneer staff present, and now it is time to verify everything we were told there. Pioneer is very proud of this formidable receiver, and with good reason.

They have dubbed it a "multichannel stereophonic amplifier". By this they mean that, in addition to strong multichannel performance, not one iota of quality is lost on the stereo side, giving it a certain music-lover's character. Besides being equipped with the latest generation of audio decoders, the design of its amplifiers could well be described as audiophile grade.



At the technological cutting edge



Perhaps that is why Keiichi Onodera, one of the engineers actively involved in developing this receiver, explained to us why the VSA-AX10Ai uses neither switch-mode power supplies nor Class D power stages: "Both technologies are very interesting, but at more or less affordable prices they do not yet deliver their full potential. The only way to offer uncompromising quality is to turn to very well-known technologies, improve them and offer something superior." The final touch to this concept was provided by the engineers at AIR Studios, one of the best recording studios, based in London, where some of the most talented sound engineers on the professional scene work. Their goal was to fine-tune the performance and quality of this receiver to achieve the most faithful sound reproduction possible, trying to emulate the tonal balance achieved in their own control rooms.

Another unique feature of this exclusive receiver is the first automatic acoustic calibration system of the sound field for multichannel environments, which they call MCACC. This circuit is an evolution of the well-known first version, which we reviewed in the previous issue with another Pioneer receiver, the VSX-D814.

The current "Advanced" MCACC, at present only available on this VSA-AX10Ai, stands out for including a three-dimensional calibration method. In its measurements the system even uses the sounds reflected in the room, ensuring a much more accurate calibration for perfect tonal balance.

The surprises continue, such as the inclusion of an i.Link input, something they already did with the VSA-AX10i in 2002. This input offers stable, true digital-to-digital transfer of high-resolution audio from DVD-Audio and SA-CD media, thanks to the exclusive PQLS (Precision Quartz Lock System), which drastically eliminates jitter problems. At this point it comes as no surprise that it also features all the latest multichannel audio decoders, including Dolby ProLogic IIx as well as Windows Media Audio 9 Professional. WMA9 Pro is one of the most recent audio formats, allowing the transfer of high-quality multichannel audio at up to 768 kbps. Finally, it is worth mentioning that inside this receiver we find seven discrete A.D.E. MOSFET power amplifiers, exclusive to Pioneer. A true benchmark.

Stereophonic philosophy



In developing this receiver, Pioneer has applied its Advanced MultiChannel Stereophonic Philosophy. With it, Pioneer answers a curious question: why can't I enjoy at home the sound the engineer hears in the studio? The VSA-AX10Ai has been designed with three basic design principles of professional audio in mind.

First of all, achieving quality audio requires quality components, such as Burr-Brown D/A converters, 32-bit SHARC Melody Ultra processors or 24-bit Motorola DSPs. The second step requires precise calibration for natural reproduction, something they aim to cover with Advanced MCACC (including the option of fine-tuning the settings manually). And the third step is to reproduce the "magic" of music, which is where AIR Studios and their final "tuning" come in.



Robust construction



The 34 kilos are not solely down to the oversized power supply, which weighs 10 kg. Pioneer has opted for a new chassis design, moving from the traditional two-dimensional approach of its earlier designs to a 3D design. This means that the chassis is a single piece of copper (which reduces interference between circuits and lowers ground impedance). Since there are no separate parts that have to be joined at right angles, rigidity is assured. Alongside this new chassis comes a 4-kilogram iron base made by TAOC (known for its audiophile-grade accessories) for greater stability and resistance to external vibrations. The material used in this base is 10 times more resonance-resistant than aluminum. To prevent any self-generated vibration, and with the help of advanced CAD (Computer Aided Design) technology, an extra 2 mm-thick metal piece has been added to the transformer.

In the amplification section, as already mentioned, we find seven exclusive discrete A.D.E. (Advanced Direct Energy) MOSFET amplifiers, which achieve superior efficiency and impressive sound quality. The layout of the seven amplifiers is no accident, as their symmetry reduces electrical, physical and magnetic effects. A quick note on the two 33,000 uF capacitors, designed exclusively for audio, which provide proper stability and instant response to power demands. Even their connection terminals have been redesigned for maximum, instantaneous energy transfer from these capacitors.

Finally, I should go over its connection panel, but suffice it to say that it is one of the most complete we have analyzed to date. See the image at the bottom of this page to confirm it.



Setup



In this case, it is worth describing the steps taken from the very moment I unpacked the receiver from its box. Apart from the fact that its weight makes it a nuisance to carry, installation is conventional. Worth mentioning is a plastic guard over the binding post section that prevents any short or leakage if we are careless with the connections. The VSA-AX10Ai was connected to a set of Focal JMLab loudspeakers and a Primare DVD30 player.

The receiver comes with a comprehensive, highly configurable remote control with a touch-sensitive LCD screen that will be enough to command all the electronic devices in our system. Even so, I must mention that the remote I used was slow to react; that is, some time passed between pressing a button on its screen and the corresponding window appearing. Perhaps a new software version would improve this. Another detail of this remote is the backlight, which can be switched on at will but makes the information tedious to read unless the room is completely dark (even after adjusting the contrast).

An omnidirectional microphone is also included, needed for the automatic setup this Pioneer boasts of. Beforehand, I assigned the digital input (in my case, I used an optical connection) and the multichannel analog input to the receiver's DVD selection (for the multichannel analog input, which I would use for the SA-CD test, simply pressing the "Stream Direct" input is enough). Although the receiver's LCD panel is of adequate size, the on-screen menu is far more versatile and useful. In case anyone missed it in the picture of the rear panel, this Pioneer has three component video inputs and the corresponding output (although in my case, as always, I did without them when connecting the DVD player).

The advanced MCACC calibration system aims to be an easy yet professional solution. The operation takes no more than 10 minutes in total, and absolute silence is required. Simply plug the microphone into the corresponding input on the front panel, place it right at the listening position and press a dedicated button. The system first checks what type of installation we have: whether or not there are surround channels (including the surround back center), a subwoofer, and so on. It even detects the size of the loudspeaker ("small" or "large"). After I confirm, a series of test sounds follows (seconds of pink noise at different levels and "clicks" that help determine the distance between the speakers and the microphone position). This calibration adjusts several sound parameters on each channel to neutralize the characteristics that color the original sound. As mentioned earlier, the aim is to measure both direct and indirect sound simultaneously.

The system is accurate to 5 cm in speaker-to-listener distance and 0.5 dB in output level. In addition to these two parameters, a moderate nine-band equalization is also performed using digital technology.

All the settings made are displayed at the end on the TV screen, although with dedicated software and a connection to a computer via its RS-232 port we can obtain a three-dimensional graph on the PC screen.

The result modifies frequency (that is, it equalizes), level and delay time (which is why we speak of a 3D calibration). All settings can be changed at will and stored in either of the two user memories. These two modes (which we can adjust for different kinds of listening) are complemented by two further modes, both generated after the automatic calibration and using its results as a basis. "All Channel Adjust" dispenses with the graphic equalization; the "Front Channel Align" mode synchronizes the other loudspeakers using the front speakers as the zero point.

The comparison between the calibrated mode and the "flat" mode reveals a great many differences, especially in difficult rooms. First, the equalization carried out is noticeable, resulting in a more balanced sound. The problem may arise with mediocre loudspeakers which, being unable to reproduce certain frequencies correctly (especially treble), are forced to reproduce them with greater force, which could end the tweeter's life. But of course, anyone spending the money needed for this Pioneer should not have that problem.

The level settings also proved perfect, something I was able to confirm with a sound level meter in hand. Distances came out almost as well, with slight differences of +/- 15 cm.

Listening to several multichannel passages from movies, the powerful energy this Pioneer is able to deliver is palpable. Its amplifiers, as well as being clean, are very fast yet capable of rendering the faintest whisper and then a powerful transient without any distortion or sluggishness. Audio decoding is very complete, brilliant and extremely well defined. There are no compromises where decoding is concerned.

The stereo image inherits many of the benefits of the multichannel performance. Excellent front soundstage, very well defined and superbly handled. There is a wealth of detail, however slight, and hard attacks are executed without any trouble.

Using high-resolution sources such as SA-CD, connected via analog (the DVD30 has no i.Link output), the VSA-AX10Ai once again demonstrates its excellent readiness for this type of format. It continues to respect high-frequency sounds without the midrange or bass obscuring them.

There is tonal accuracy across the entire audible spectrum, even if the use of the equalizer might suggest otherwise. Some will question the use of an equalizer as something that noticeably alters the sound, although in the case of this Pioneer receiver, and understanding the role of the MCACC system, rather than an equalizer we should label it a problem "solver". The manufacturer does not specify actual power in W RMS, only in DIN form, which usually gives higher values. It also does so into 6-ohm loads, rather than the standard 8. Even so, the power is sufficient for the vast majority of loudspeakers, however insensitive they may be. Sound pressure is guaranteed, with faithful tonality maintained over much of the volume range.

Perhaps the technological abundance applied in this receiver (which in any case is never a bad thing) will make some users wary, those who seek the highest fidelity without any artifice. Well, all they need to do is switch off any "added" feature and carry on enjoying high-quality sound and excellent performance. There will be time enough to discover the advantages Pioneer offers with the VSA-AX10Ai.

The VSA-AX10Ai is not the best A/V receiver in its price range, but it is one of the best (at the very least, it is the flagship of a manufacturer as respected as Pioneer).

And it is one of the few that has managed to balance, almost perfectly evenly, the needs of multichannel audio with the demands of stereo, without neglecting, quite the contrary, the advantages offered by high-resolution formats such as DVD-Audio and Super Audio CD.

With MCACC, Pioneer demonstrates that a perfect setup is possible without user intervention (only needed when the user wants surgical-precision adjustment), a clever solution that does not sacrifice ease of use and delivers more than decent results. Useful, in any case, from a simple guide template to a perfect calibration suitable for users who want to enjoy a very good system without worrying about the intricacies of setting up an A/V system. A coherent choice for users who like to be up to date.

Pioneer VSA-AX10Ai-S, Pioneer's beast laid bare

Specifications

7x170 W DIN (1 kHz, 1% THD, 6 ohms).

Dolby Digital EX, THX Surround EX, DTS-ES Discrete/Matrix, DTS Neo:6, DTS 96/24, Dolby ProLogic IIx, Windows Media Audio 9 Professional, THX Ultra 2 Cinema.

5-100,000 Hz, +0 dB, -0.3 dB.

86 dB phono, 105 dB DVD/Line (IHF).

MCACC (Advanced MultiChannel Acoustic Calibration System).

SHARC Melody Ultra 32 bit, Motorola 24 bit.

192 kHz/24 bits on all channels.

Inputs: 2 i.Link, USB Audio, 2 Trigger, 1 RS-232C, 7.1 multichannel analog, RF, 3 S/PDIF, 4 EIAJ-TosLink, 7 stereo analog, phono. Outputs: 2 EIAJ-TosLink, 5 stereo analog, 7.1 multichannel analog.

Universal, with touch-sensitive LCD screen.

725 W (0.65 W in standby).

440x210x476 mm.

34 kg.

Price: €4,890