Pros: Superb for cinema AND music, now a bargain buy, exceptional connectivity options
Cons: Now obsolete with the AZ1 having Dolby PrologicII
Update Jan 2004
I've just finished building an mp3 jukebox (Asus VMSE microATX (uATX) mobo, Duron 1.3, 256 DDR, 80GB maxtor quietdrive and Creative SB-Live-Value! card with a hoontech soundbracket3 spdif i/o adaptor). It's running Windows2000, and is controlled using a VNC session, and it runs winamp5 with the full media browser to allow selection of music.
I've plugged this into the AX1's minidisc input and output, and am very pleased with the results on music ripped from CD (I am. The downside of the SB PCI card is that it's got a fixed sampling frequency of 48kHz, and whilst all the inputs on the AX1 auto-switch between 44.1, 48 and 96KHz sampling rates, the AX1 *seems* to output to MD at 44.1kHz only - i.e. it doesn't follow the original source. This means that for analogue sources, the AX1 samples it at 44.1 (I think!), then resampled to 48 by the SB!. However, if the origin is the digital radio, digital tv, or digital satellite receiver which all run at 48, then the signal appears to be downsampled to 44 by the AX1 and then resampled back to 48 by the SB.
I'll update this as I know more, but if you want to make the most of the quality of the AX1, I'd recommend getting a soundcard that has multiple sampling rates and thus reduce the number of signal processing stages!
Warning! Apparently the standard coaxial digital out on Creative's Soundblaster cards is not within s/pdif standard, and can, apparently, damage AV amplifiers, so be warned about simply getting a 3.5mm jack to RCA phono lead and plugging your PC directly into your amp!
Update May 2003
I bought a "quintro" four-way RGB/scart switchbox from keene.co.uk and so have bypassed the AV amp for any video functionality. It's certainly made the whole thing much easier to use, as the switchbox changes AV source automatically, meaning that the TV is left in AV mode, and then all you have to do is select the audio source on the Yamaha.
The terrestrial digital TV broadcast in the UK seems to carry Dolby Prologic, though not 5.1, and so gives a definite improvement over the plain old analogue Nicam sound. Hopefully they'll do 5.1 one day; I'd go for Sky satellite except that you have to have the expensive Sky+ system to get 5.1 (the Sony receiver has s/pdif out, but it's not 5.1!)
I am so glad I bought the AX1 instead of AX2, although I don't need the extra power, the extra inputs on the AX1 has been a real boon - I'm using all the coax s/pdif inputs because of the older a/v kit -I never thought I'd need so many I/Os!
Update March 2003
I now have a terrestrial digital television receiver, a Nokia Mediamaster, and this has an S/PDIF coaxial digital output. This D-TV system is used in the UK and some other European countries. The system outputs sound at 48kHz sampling. I've observed Dolby pro-logic surround sound on some movies, but never full Dolby Digital 5.1.
I also now have a Microsoft X-box (the second version of the xbox, which has a Philips DVD drive in it). I bought the RGB scart lead for it which has an optical s/pdif connector. The sound is very good, offering full DD5.1, and on Project Gotham Racing, for example, I find myself looking over my shoulder for the cars trying to overtake.
I intend to get a separate RGB switchbox, and abandon the Yamaha as a video switch; the mess of cables comprising RGB scart-scart, composite phono to scart, and S to scart, have all been too much, especially with the xbox and d-tv box. www.Keene.co.uk have the best one at the price I can find, which is 4 RGB ports plus one CV port. Having been married for a while I find my wife has trouble working out the right combination of TV channel and Yamaha settings to get both a picture and sound, so I have the perfect excuse to spend the 80 pounds ($130).
Update January 2002
I've now completed another set of cabling and interfacing, so here's the latest news.
Firstly, I've routed the S video from my DVD player through it, having connected the TV to the "S monitor out" on the AX1. The DSPAX1 overlays its configuration information over the top of the display when anything changes, this makes it much easier to fiddle with the AX1's settings and see what it thinks it is up to. It works very well. Note that the AX1 doesn't do any conversion, so if you connect up the composite video of a VCR, you'll also have to connect the CV out from the AX1 into the television. The other problem I have noticed is that, here in the UK where we use 50 fields per second PAL for TV, that playing region-1 NTSC disks upsets the AX1, I guess that its video overlay circuitry doesn't sync to anything other than 50Hz. This means that I have to switch to the RGB port on the DVD player, disconnecting the satellite receiver (being able to watch NTSC sources off satellite is far more useful than the occasional region 1 NTSC disk).
Secondly, I've had a chance to test the (European DVB/S system) Echostar Ad3000ip satellite receiver's digital audio out (coaxial connection) and it works just fine.
The AX1 indicates PCM @ 48kHz sampling rate. When there's dolby digital (whose standards have only been ratified relatively recently), the satellite receiver will automatically select DD (if enabled in the menus), and the AX1 will generally switch too if in auto mode; sometimes it doesn't, I suspect the Echostar is at fault. The display indicates which DD mode is active, 3/2 etc. The Yamaha manual doesn't really talk about these technical modes, to be honest, which is a shame.
Finally, I discovered that the maximum length of a coaxial SPDIF cable is far more than the 10 feet or so I previously expected! I managed to use my PC upstairs over a long run of shielded cat5e to drive digital audio into the Yamaha. The sound quality wasn't as good as I expected, so maybe there is a high bit error rate? I'd love to know how to do this properly, so I could use my PC as an mp3 jukebox. My PC is equipped with a plain old Soundblaster Live!1024!Value card, and then I used a SPDIF adaptor set from www.Hoontech.com (which is much cheaper than buying an SB Platinum card!).
--- previous review ---
You can read all the specifications online so I'll not play the numbers game and concentrate on what it's like to own one. Suffice to say both were built by Yamaha to have no real compromises - only Denon have produced something more expensive (and review indicate overly complex)! Only if you go to the specialists like Tag McLaren will you get anything better?
I have a black DSP-AX1, and have compared it extensively with my friends A1. The A1 has been obsolete since 2000, the AX1 obsolete since late last year. The A1 is still available in some dealers, sometimes as a second-hand unit, otherwise as ex-demonstration. The AX1 was being heavily discounted late 2001, often at less than half the original recommended price. The reason for this, so I believe, is that the DSPs inside the AX1 cannot have their software upgraded to handle prologicII (as if I particularly care!); this has annoyed many who bought the AX1 expecting some degree of future proofing with its serial port and suggestions of upgradeability. I got mine at less than half the recommended price (even including the expensive delivery costs!).
Why buy one over the other?
For the vast majority of people, there's little to choose between them; the AX1 has additional amplification channels to cope with the enhanced dolby digital and DTS modes, but unless you really want TEN speakers in your system, and absolutely have to have the latest, the A1 is still brilliant. Note too that they allow you to easily connect up an external decoder/multi-channel source, so even if yet-another-surround-sound system comes out, you don't have to worry about losing your investment.
Physically they're very much alike. Both are available in black or gold, and only have minor rear panel differences. The A1 has a much nicer remote control than the AX1, both are full learning remotes, but the A1's hides a lot of the unused buttons. The AX1 only has special function (setup/test) buttons hidden, but does have a little LCD display in it.
These amps will reproduce music with stunning clarity and depth of bass - not for nothing do they weigh about 30kgs, or over 60 pounds! The power supplies are huge! Expect to need two people to lift into awkward positions! This allows the huge power reserves to give the solid sound.
They also accept every different type of input imaginable, analogue, digital/coax, digital/optical and digital/RF/coax from laserdisk players. You can make the inputs auto-detect, thus keeping it easy.
You can tweak the cinema sound according to your tastes, and environment... if you have very near neighbours you can change the dynamic range of cinema sound so that climaxes don't get so loud it'll wake them up. You can set the delays to compensate for the room.
You can tune individual speakers - most useful for the rear surrounds - to make the most of the limitations of your room (I was able to add delays so that the rears seem further away), and to compensate for the different sizes of speakers (my rear effects are much smaller than the main/front ones). If you don't have certain speakers (I don't have a center/voice or sub-woofers) and it will mix the sound to give a reasonable alternative through the main speakers.
You can have a second speaker zone, useful for say the kitchen, so all you'd need is an infra-red extender/repeater and not need a complete 2nd hifi there.
Not only does it do all the audio switching, it also does video. Note that the switching is aimed at S-video or composite, and so not so useful for European markets which use SCART. There's also component video, great for US market but no good for Europeans who use RGB and SCART connectors; one day I will see if I can use the component video switching to carry RGB instead! However, the DVD standard means that using S-video doesn't detract much and means you can use the A1/AX1 to expand your TVs input selector easily (to cover say the VCR and DVD player).
The amp has some neat tricks to expand ordinary two-channel music inputs to give a "fuller" sound. Many of these are over the top, and being a purist I mostly leave the effects off, using them only for movies. I agree with the reviewers that the amp is superb for music (I have a Pioneer DVD player linking the digital out to the amp), which is the exception when it comes to home cinema equipment.
I'll be coming back to this review when I've hooked up the satellite receiver (Echostar AD3000ip) and can discuss the quality of digital audio from European satellite sources and proven to myself whether they are really transmitting proper dolby digital audio! (SEE ABOVE FOR UPDATE)
I paid GBP925 (about US$1500) for my AX1, and I could have bought an ex-demo A1 for about GBP750 (US$1200)