Diamond Monster Sound MX400

Review date: 17 March 2000.
Last modified 03-Dec-2011.


Bigger is not always better. Take boils, for example. Or asteroids that cross our orbit. But when it comes to computer gadgetry, you can generally trust that the UltraZoot 4000 will be better than the old UltraZoot 2000. It seems pretty obvious, right?


Well, here's the darn Diamond Monster Sound MX400 to upset the applecart. Like Diamond's rather older MX300 (which I review here), the MX400 is a high end sound card with positional audio support, four speaker output, ultra low noise and a decent software bundle. But it's not really a better board. Newer, yes. Cheaper, even - it sells for $AU179 for the full retail boxed version. But better...

Well, perhaps.

In basic specification, the MX400 is similar to the MX300, with one significant addition - an RCA S/PDIF output, that lets you output full Dolby AC-3 surround sound to a compatible decoder, like the ones in home theatre amplifiers, when you're playing a DVD on your computer. Cards this cheap don't normally have this feature, and all by itself it makes the MX400 highly interesting for home theatre enthusiasts. The connector's not much use for anything but Dolby Digital audio output to a compatible decoder, though; as is usual with PC sound cards, it's just an output, not an input.

Apart from the S/PDIF, the MX400 has the same basic connectors as the MX300 - front and rear stereo 1/8th inch speaker connector sockets, a single stereo line in, a single microphone in, and a joystick port that doubles as an MPU-401 MIDI interface connector, with an optional adaptor cable. The MX400 it does the same basic thing as the MX300. And its main market is the same - game players.

Game support

The question for avid gamers is simple - can I get 3D sound with Game X?

And the answer, these days, is a resounding "maybe". It all depends on what your sound card can do, and what your game wants.

The old MX300 uses Aureal's Vortex 2 chipset, which is still right up there with the best of them. Aureal's standard reference drivers work fine with the MX300, so it's now just as good as any newer Vortex 2 board, and supports all of the popular 3D sound Application Programming Interfaces (APIs).

Sound APIs work the same way as 3D graphics APIs like Direct3D and OpenGL and Glide; they're systems programmers can use to do a complicated job without having to write all of the complicated code themselves. When a sound card's driver supports a given API, any software that uses that API will work with the sound card.

Canyon3D chip

Both Aureal and Sensaura use HRTF with crosstalk cancellation when you set the output mode to two or four speakers, as opposed to headphones. Crosstalk cancellation tries to stop sound that's meant for one ear being heard by the other, and is necessarily imperfect; headphones are still, really, the way to go for really sharp 3D localisation.

The MX400 uses the newer ESS Canyon3D chipset, which employs Sensaura's 3D sound technology. Sensaura have their own 3D sound technology, like Aureal, but they split it up into little bits with different names.

Sensaura's "Virtual Ear" technology, for instance, lets you tweak the system's HRTFs to more accurately match your ears and playback system. "EnvironmentFX" is a canned reverb system; it's basically just what Sensaura calls their support for the EAX, EAX 2.0 and Interactive 3D Audio Rendering Guidelines Level 2.0 (I3DL2) APIs.

I3DL2, by the way, is yet another reverb API. It comes from the Interactive Audio Special Interest Group (IA-SIG), which includes Aureal, Creative Labs and Sensaura. ID3L2 builds on EAX 2.0, and is as yet not at all popular - but Microsoft will include support for it in DirectX 8, which ought to kick-start the standard.

Back in the snappy name department, Sensaura's "MacroFX" handles sounds meant to be very close to the listener, and "ZoomFX" makes large sound emitting objects, like trains, sound right. Without a system like this, they're just point sources or clusters of sounds.

"MultiDrive" is Sensaura's multi-speaker technology, and they claim it "seamlessly integrates front and rear sound hemispheres".

This is one area where the Sensaura chipset has an advantage over the Vortex 2. The Aureal cards only apply their HRTF magic to the front speakers, and use plain old stereo panning for the rears. The various Sound Blaster Live! cards originally did four speaker mode the same way, but since the 2.0 version of the Live!Ware software they've supported proper four speaker HRTF sound too.

In practice, the stereo-panned-rear system actually works perfectly well most of the time - there's an occasional obvious transition when a sound source moves from one pair of speakers to the other, but it's seldom very noticeable. The Canyon3D solution, though, has no such glitches - at the price of using up more 3D sound channels.

Fortunately, the Canyon3D has plenty of hardware 3D channels to spare. 48, in fact, with the Diamond drivers. The Canyon3D is one of the more powerful pieces of Sensaura hardware.

One sound channel gets used for every sound that needs to be played simultaneously - but those sounds can be coming out of as many of the card's output channels as you like. It doesn't matter how many speakers are playing the noise of that game object that's whizzing round and round you; it still only uses one channel.

When sound cards run out of hardware 3D channels they can do one of three things. They can do the 3D processing in software, but that causes a big performance hit. If it didn't, there'd be no reason to bother with all of this 3D sound hardware.

Alternatively, they can just deliver extra sounds in ordinary stereo, with no fancy 3D effects. Which can sound quite weird. Or they can drop the extra sounds on the floor and not play them at all.

Obviously, it's really nice to have lots of hardware channels.

The Vortex 2 chipset has only 16 hardware 3D streams, but it's got another 60 channels for wall reflections in A3D 2.0 and above. If you're not using the fancy A3D 2.0+ wavetracing, the current Aureal drivers make the 60 extra channels available for ordinary audio streams, and this puts the Vortex 2 well ahead of the Canyon3D.


The carving up of Sensaura's 3D positional audio technology into lots of separate things is, essentially, just marketing-speak; if you can't get enough of it, check out Sensaura's page here. What it boils down to is that Sensaura have themselves a 3D sound system that's ahead of the rest in a couple of departments and not far behind in others; this is not a low-end 3D sound solution, although some other Sensaura cards certainly are.

On top of their own stuff, Sensaura systems also support the other "open" 3D sound APIs that anybody can use - Microsoft's DirectSound 3D, Creative's open-standard EAX and EAX 2.0 and, as mentioned above, I3DL2.

Most of the special Sensaura stuff is, actually, incorporated as transparent extensions to DirectSound 3D. This means that anything that uses DS3D will automatically produce better results on a Sensaura card. You don't have to wait for game support; it's there right now. The MacroFX close-sound improvements will work whenever a game puts a sound close enough to the player, for instance. The ZoomFX extension has to be specifically supported by the game, though.

The Aureal alternative

With a Vortex 2 board like the old MX300 and the current (version 2.048) Aureal drivers, you get support for all of the non-Sensaura stuff the MX400 can handle, plus Aureal's A3D 2.0 and 3.0. Which pretty much covers every 3D API used in any game today.

The latest SQ2500 Vortex 2 cards (I review one here) from Aureal themselves have a slightly updated version of the chipset with marginally higher performance, but the difference is negligible. Vortex 2 is Vortex 2, as long as the manufacturer doesn't mess about with the reference board design, as for example Turtle Beach did with their Montego 2 Quadzilla (reviewed here).

The biggest deal about these 2.048 Vortex 2 drivers, and a big selling point for Vortex 2 boards against other cards like the MX400, is that the new drivers include support for the new A3D 3.0.

This explains why it took the drivers so very long to arrive - they were originally billed as just adding EAX support, which wasn't such a big deal. Enthusiasts were irked and puzzled by the late delivery of the new software. But the A3D 3.0 update includes considerably more features than the fans were expecting.

The original A3D 1.0 is just positional audio, with no environmental frills. It can easily be emulated by other cards, including the MX400, by turning A3D calls into DirectSound 3D ones.

A3D 2.0 added occlusions and reflections, from accurately geometrically rendered surfaces, and also had environmental sound modification. This lets A3D 2.0 supporting games properly change sounds when you're meant to be underwater, for instance.

A3D 2.0 also added "A2D", the software-only reduced version of A3D 2.0 that works on any old sound card, but at the cost of a big fat performance hit. You can use A2D with the MX400 and get results no worse than those from any other sound card, because all of the work's being done by the CPU.

A3D 3.0 adds volumetric sound sources, which work like Sensaura's ZoomFX; you can have a great big crowd or babbling brook or train that emits a sound from its entire volume, not just from particular points.

A3D 3.0 also lets games play MPEG 1 Layer 3 (MP3) compressed sounds as positional audio sources, as well as supporting the usual uncompressed sound formats. This isn't necessarily a great idea on slower computers using current sound cards, without hardware MP3 decoding. But recent machines can take MP3 decoding in stride, even in games, quite comfortably. And the super compression offered by MP3 means something like ten times as much sound can be packed into a given amount of disk space.

The EAX reverb support in A3D 3.0 is actually a fall-back setting, for games that specifically want to use EAX or don't work with A3D 3.0's own geometric reverb system. The A3D 3.0 reverb seamlessly falls back to I3DL2 or EAX reverb when it's not supported.

There's also support for streaming audio - audio that plays as it's delivered, rather than making the user wait for a whole file to download - built right into the drivers.

Setting up

Installing the MX400 is no harder than installing any other PCI sound card - pop case, turf out old sound card, insert and screw in new one, close case, reboot, let Win95/98 detect the new card.

If you're not running Windows 95 or 98, though, you're pretty much out of luck. There are Windows NT drivers, which have no positional audio support because Windows NT doesn't dig DirectSound 3D. It is, apparently, possible to get the MX400 working in Linux, again without positional audio support. There's no Windows 2000 driver yet, and users of more esoteric operating systems can go whistle.

The default driver install doesn't saddle you with any particularly weird programs; the "InControl Audio Tools" MX400 control panel is simple and straightforward. The only thing that's missing is a tweaker for the "Virtual Ear" feature; until the drivers support this, or a stand-alone utility is released, Sensaura's HRTF tweaking feature isn't available.

The bundled drivers, which are also the most current ones as I write this (check here to see if they still are), also include DOS game sound support, via the usual Sound Blaster Pro emulation.

Early drivers for the Canyon3D were crummy, and led people to lump it in with other, cheaper Sensaura technology products, as no match for the Vortex 2 or Sound Blaster Live! Diamond's drivers, though, cure all of the performance and channel number problems, and make the chipset a real contender.

There are two internal MPC2 standard connectors on the card, one for CD audio and one for an internal modem sound connector, with the usual single cable for the CD hookup.

There's also a header that lets you send PC speaker sound output out through the MX400's jacks, if you want, and the usual four pin "legacy" connector that you can hook up to elderly TX chipset motherboards to help with DOS games that don't understand PCI sound cards.

The header on the back of the MX300 is for the upcoming Rio PC hardware MP3 encoder/decoder board. With this card added, the MX300 will be able to encode MP3 data rather faster than even a high-end PC can with a software encoder. This may be quite handy for people in the business of making MP3s, as the Rio PC is likely to be a lot cheaper than previous hardware encoders.

For home users, the Rio PC won't make much difference; even a modest Celeron box should be able to encode tracks in less time than it takes to play them, and many low-cost CD-ROM drives don't do great audio reading at speeds above 1X or 2X, anyway.

The Rio PC will apparently also include an FM radio tuner. This revolutionary, clamoured-for feature will no doubt make it a record-breaking bestseller.

Software bundle

You get a couple of extra discs along with the MX400's main software CD. One's the standard bundle disc, with a decent seven level demo of the giant-robot shooter Slave Zero, and the "NetActive" demo version of the smash-up driving game Demolition Racer.

In a new twist for crummy cut-down demo software, the NetActive game will only let you play for one hour, and then only if you've got an Internet connection active. If you like it, you can buy it for $US14.95 over the Web and unlock it for full play, or pay less to rent it for a bit longer.

It wouldn't have hurt if the people who wrote Diamond's back-of-box copy had given some hint that this was the case, though; Joe Average would be likely to think that "NetActive" indicated a better version of the game, not a heavily limited demo.

You also get Mixman Studio FX, which lets you do your own MP3 mixes. There's a selection of sound player programs as well, and Diamond's RioPort Audio Manager, a perfectly good MP3 encoder, player and organiser.

There's Yamaha Soft Synthesiser, which uses CPU grunt to imitate a quite capable MIDI module for high quality music playback. Soft Synthesiser sounds noticeably better than the MX400's standard on-board MIDI, which is OK but not quite up to the standards set by the Sound Blaster Live!

More significantly, you get the full version of Zoran's simple but popular SoftDVD DVD playback package - an excellent pack-in for home theatre buffs.

One thing to remember about S/PDIF equipped cards like the MX400 is that your DVD playback software must support your particular sound card - or, at least, the chipset your card uses, if it's a standard model card. SoftDVD supports the Canyon3D, so all is well if you want S/PDIF output and you're happy to use the bundled software. If you want to switch to a different DVD playing package, though, check to make sure it supports the card you intend to use.

Actually, SoftDVD is very well suited to the MX400; it not only handles downmixing of 5.1 channel sound to the four outputs of the MX400 (if you're not using the S/PDIF output), but it can even use HRTF manipulation to give you ersatz surround from only two speakers.

There's also Soft Karaoke Lite, which allows you to commit crimes against music in the privacy of your own home.

And that's not the end of it. There's another disc, too, which isn't even mentioned on the back of the box. It's Infogrames' "Family Spectacular", which contains superannuated platform game for kids Super Busby, not very new race game V-Rally, and trial versions of golf game Jack Nicklaus 5, baseball game HardBall 6 2000 Edition and not-very-realistic driving game Test Drive 5. And there are 10 video golf lessons from Jack Nicklaus in MPEG-2 video format.

How do they fit all of that on? By making it a DVD disc, that's how. Without a DVD drive, you can't even read it - but don't get too bothered, because everything except V-Rally and Super Busby is just demos unless you, again, choose to exercise your credit card on the Internet and pay to unlock the full versions of the trial games, which are on the disc but unusable until you pay for a key-code.

Given that freebie pack-ins are often pure rubbish, all of this stuff together is actually pretty good.


If you've got a slow computer, positional audio will make it somewhat slower. A3D's super-fancy tricks have a significant effect on game frame rates on even fire-breathing machines, but you're not going to be doing things that complex with the MX400, because it can only emulate A3D 1.0. You can do sorta-kinda A3D 2.0 via the A2D emulation drivers, but the performance loss is quite drastic.

When it's just doing DirectSound 3D and EAX work, the MX400 chugs along very pleasingly, slowing down most systems by only a few per cent. You'll get less slowdown if you use a Sound Blaster Live!, but the difference isn't big.

If you switch to the MX400 from an ISA sound card, you'll gain a little bit of performance anyway since there's less CPU overhead from sound cards on the newer system bus; in any case, the difference is likely to be impossible to notice.


A clear successor to the MX300 this card is not. But neither is it a poor choice; Sensaura technology with Diamond's drivers is definitely ready for prime time, the four speaker output sounds great, the S/PDIF connector is a nice touch for those that want it, and the price is right.

If you've got to have the latest A3D capabilities, then you want a Vortex 2 card. But then again, EAX 2.0 sounds pretty darn good compared with A3D 2 or 3, as long as the game programmers have their act together - the EAX effects settings have to be intelligently chosen and change in the right places.

Programmer input makes all the difference for A3D 2 and 3, too; either system can sound weird if it's not told what to do properly.

Using EAX 2.0 and DirectSound with the MX400, especially with four speaker output, gives a result that's arguably better than Vortex 2 performance, especially when there's lots going on. The proper all-around HRTF output and greater number of hardware 3D sound channels makes a difference.

It's certainly not a night-and-day difference, though. Owners of a card based on one chipset needn't rush out to audition a card based on the other. But the Canyon3D, with its current drivers, is still a real contender.

Of course, it's only a contender if you're playing a game that supports DirectSound 3D and its various extensions. If your game works with A3D 2.0+ - this is the case with Quake 3, for instance - then it should fall back to DirectSound 3D when you don't have A3D hardware available; you lose the fancy A3D extras, but you still get positional sound. A2D isn't really an option unless you've got a CPU From Hell.

Most positional audio games work fine with DirectSound 3D, though; you're not really going to miss out on too much if you don't have a Vortex board. Check which games you like use which API, and you'll probably find an MX400 will suit you just fine. For the money, it's a great bit of gear.




  • Four speaker output and S/PDIF
  • Broad API compatibility
  • Good price
  • No A3D 3.0 or proper A3D 2.0

3D audio flavours

Any half-decent sound card these days has impressively quiet input and output, and can be used for quite serious studio digital audio work, as long as you're happy with basic stereo analogue input and output and don't need fancy digital connectors. But funkier cards like the Monster Sounds have hardware that lets them do positional and environmental audio. They are for sound what 3D accelerators are for video.

Positional audio uses advanced psychoacoustic tricks to give you the impression of true 3D sound. In front, behind, above and below; sound sources can be quite clearly localised. This extra realism is more fun, and can be quite handy; as you crouch behind a crate with machine gun in hand, it doesn't hurt to be able to definitely tell which side of the box your enemy is about to walk around.

The positional audio is really only coming from two or four actual transducers - dual or quad speakers, or the twin transducers in headphones. But the Head Related Transfer Functions (HRTFs) used by the different positional audio systems fool your brain into thinking otherwise.

The theory behind HRTFs is, in essence, pretty simple. Humans only have two audio-detecting devices - those little tympanic membranes in our ears - but, without moving our heads, we can locate sounds all around us. The way we do it is by analysing the spectral and phase changes in the sounds that are picked up by each ear; the head, the ears and the environment all change the sound that's emitted by things and the brain decodes the phase rotation and reverberations and relative delays and frequency emphases. Fake some or all of those tell-tale distortions, and you fake the location information too.

Actually doing it, of course, is a heck of a lot more complicated than the basic idea. But it can be done, and it has been done; real honest-to-goodness 3D sound, even if all you've got is two speakers. With headphones, it can be spookily good.

Environmental audio is, usually, simpler; it's the simulation of what sounds do in particular spaces. It can be simple, just applying canned reverb effects to the sound you hear, or it can be complex, actually "wavetracing" the sound so you get proper wall reflections and sound occlusion by objects.

Even the simple kind of environmental audio doesn't just pick from its few dozen presets and stop there; game developers can specify the level of the reverb and the ratio of reverb to unaffected sound.


5.1 channels: Surround sound systems with six speaker outputs (left, right, centre, left rear, right rear, subwoofer) are often referred to as "5.1 channel", because the subwoofer Low Frequency Effects (LFE) channel outputs only low bass sound, not the full range of frequencies.

7.1 channels: The 7.1 channel format adds extra left-centre and right-centre channels to the standard 5.1 format. It's supported in DVD only by discs with an MPEG-2 soundtrack, and even then is very rare. Which is just as well, because practically nobody has an audio-visual setup that can play it.

AC3: This was the original name for the Dolby Digital sound system used on the majority of DVDs, and it's still the name for the kind of compression it uses. Dolby Digital uses lossy compression, conceptually similar to the ATRAC encoding used by Minidisc and the MP3 (MPEG 1 Layer 3) computer audio format, to squeeze audio data into a much smaller space. AC3 sounds better for a given data rate than the older ATRAC and MP3 formats.

The normal data rate for plain two-channel stereo AC-3 is 192 kilobits per second (kBps; one kilobit is 1000 bits), and the format supports bit rates from 64 to 448 kBps. 384 kBps is the normal bit rate for 5.1 channel AC-3 surround, and this bit rate is used by many DVD movies and all laserdiscs (the old LP-sized analogue video discs) that have an AC-3 surround soundtrack.

For well-encoded MP3 audio, 64 kBps per channel is enough for near-CD quality (better than FM radio) sound reproduction; 80 kBps per channel tidies up pretty much all of the remaining artifacts.

In 5.1 channel mode at 384 kBps, AC-3 uses 64kBps, but its superior sound quality at a given bit rate makes it about as good as CD for even critical listening. It's widely agreed that AC-3 surround at the full 448 kBps speed sounds only slightly better than 384 kBps. The AC-3 standard actually technically supports bit rates up to 640 kBps, but the implementation of it used in DVD doesn't. The general consensus is that 448 kBps AC-3 sounds as good as any other 5.1 channel system, including the much heftier DTS (explained, along with the other DVD movie audio flavours, here).

PC 99: Microsoft's latest standardised PC design specification, which like Microsoft's previous specifications will no doubt be adhered to in whimsical ways by different manufacturers.

For more information on PC 99, see the Design Guide here.

MIDI: Musical Instrument Digital Interface, the standard protocol for hooking together electronic instruments. PC sound cards have on-board MIDI music capabilities, and can also have a special cable connected to their joystick port to allow the connection of external MIDI devices.

MPC2: Another software and hardware standard, created by a computer company consortium led, again, by Microsoft, but rather older than PC 99. In this context, MPC2 just describes the kind of connector used by various sound cards for internal analogue audio, for instance from CD-ROM drives and internal modems.

MPU-401: An old dedicated MIDI interface card for IBM compatibles, which is emulated with varying degrees of success by various sound cards.

S/PDIF: Sony/Philips Digital Interface Format is an audio transfer protocol that can use either optical or electrical connectors - electrical, in this case. It's used to transfer either 16 bit stereo audio data between various components (CD players, Digital Audio Tape decks, some sound cards), or to transfer Dolby Digital (formerly known as AC-3) 5.1 channel audio for movies.

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