When Yamaha announced its DSP Factory last year, it sent more than a few ripples across the pro-audio pond. Advertised as an 02R mixer and digital audio

When Yamaha announced its DSP Factory last year, it sent more than a few ripples across the pro-audio pond. Advertised as an 02R mixer and digital audio recorder on a card, the DS2416 promised to put a studio inside your computer. A stampede of software vendors pledged support for the DSP Factory, and the race was on to exploit Yamaha's new creation to its fullest potential. Now that the dust has settled, only a handful of serious contenders has emerged.

One industrial-strength option for DSP Factory support is MxTrax 2.4.4 from Minnetonka Audio Software. MxTrax was previously introduced for the Digital Audio Labs V8 system, but the version I reviewed was created specifically for Yamaha's DSP Factory products, which include the SW1000XG expansion card, AX44 analog I/O expansion box, and AX16-AT ADAT-interface card. (For a comparison of the two versions, see the sidebar "DSP Factory vs. V8.")

For this review, I installed MxTrax on a Celeron processor-based PC overclocked to 450 MHz with 128 MB of RAM. The test system used two 7,200 rpm IDE hard drives, one for program data and one for audio. Installing MxTrax from the CD was a simple task and took only minutes. The supplied copy-protection dongle attaches to the PC's parallel port.

VIEW FROM THE TOPIf you have some experience with tape-based studios, MxTrax should look and feel quite familiar. The program's interface is based on two main windows: the Track window and the Mixer window. The Track window is where you view and edit sound files from disk; each channel of audio appears as a track. The Mixer window is where you mix tracks from disk and external inputs. It looks very much like a traditional mixing console, with channel strips, faders, and other controls. The two windows normally appear in a split screen with the Track window on top and the Mixer window on the bottom (see Fig. 1). Separating the two windows is a small horizontal area that contains the transport controls.

The overall appearance of the program is pleasing, and the earth-tone color scheme is easy on the eyes. In addition to the standard Windows menu bar across the top, Minnetonka has graciously provided hot keys for nearly every menu function. For example, a press of the F2 key instantly puts you in full Mixer view, F3 in full Track view, and F4 in split-window view. Many of the MxTrax screen items also offer right-click menus.

MxTrax saves your work as a project, which consists of tracks, mixer design, automation, and edits. I like the simplicity of saving and retrieving everything under a single name. In addition, you can save several mixes of the same source material as different projects.

The program comes attractively packaged and includes a well-written (though unindexed) manual with plenty of screen shots and diagrams. Online help is available within the program, as well. Several multitrack tutorial projects are included to demonstrate the program's features.

KEEPING TRACKThe Track window displays a graphic representation of your digital audio files. To the left of each track is a Track Control area with Solo, Mute, and Record-Enable buttons. You can set a track's display size to Normal (the default), Full (for more detail), or Mini (for the smallest possible display). The Mini size is especially useful with a small monitor.

To add a track, select Add from the Track menu. You can also add WAV files from other programs to your project. As tracks are added, a scroll bar lets you move tracks into view. MxTrax supports 16-bit or 32-bit audio files. For 32-bit resolution, however, you must use version 1.003 or later of the DSP Factory driver.

You can mix tracks with different resolutions; the program converts them to the project default. However, you may lose precision in the audio data by using 32-bit audio files in a 16-bit project. Also, keep in mind that 32-bit projects-and any projects that require conversion-consume extra CPU resources.

While there is no limit to the number of tracks in a project, only 16 disk tracks at a time can be connected to the mixer. Most of my projects use more than 16 tracks, so I find this a bit limiting. Of course, adding a second DSP Factory card would allow 32 connected disk tracks. (Each card also offers 8 live inputs, for a total of 24 input channels per card.)

DO IT YOURSELFThis is my favorite part: in MxTrax, you build your own mixer! With a unique feature called the Component Toolbox, MxTrax provides a drag-and-drop scheme that lets you build your mixer exactly as you want it. You can create a custom mixer for each project or build a generic default mixer as a starting point and then customize it further as necessary. The Component Toolbox includes the following drag-and-drop objects: input channels, output channels, pan controls, EQ, aux sends, text labels, buttons (Solo, Mute, Record-Enable, and Automation), dynamics, attenuator, phase, delay, and effects returns.

MxTrax supports the DSP Factory EQ, dynamics processing, and DSP effects. For those with two DSP Factory cards installed, the program works right out of the box, providing an impressive 48 input channels with full DSP EQ, dynamics processing, and effects. The current version of the program doesn't support DirectX plug-ins, but DirectX support is slated for a future update.

Building a mixer is easy. To add an input channel, simply click on the Input Channel icon in the Component Toolbox and drag it into the Mixer window. A single channel strip, complete with a fader and LED-style VU meter, drops into place. To add a pan control, just click the appropriate icon in the Component Toolbox, and drag and drop it onto the channel strip. Need a 4-band EQ? Click, drag, and drop! The components all snap to a neat vertical arrangement down the channel strip (see Fig. 2).

Another particularly nice feature allows a single channel strip to be saved and loaded into other projects. You can also copy channel strips and paste them multiple times into the Mixer window. The Channel Copy command is very helpful when you need to quickly create a big mixer. Depending on the project, a custom mixer can become quite large and complex, so I recommend setting your screen resolution to 1,024 5 768 or greater. As with any multitrack program, a large monitor is always an advantage.

Output channels and effects channels are also built up from drag-and-drop components. For example, to add the DSP Factory effect called Reverb Stage, you click the FX icon in the Component Toolbox and drag the effect into the Mixer window. To connect audio to the input of the DSP effect, you click on the effect name and drag it to the desired input channel. The cursor changes during the drag to indicate an effects-to-aux connection. When you release the mouse button, a postfader aux-send knob appears on the input channel. You can change the aux send to prefader by clicking the Pre/Post button. With the Component Toolbox, you can build a software "mixing surface" that suits each project perfectly.

SMOOTH MOVESBecause of the program's tight integration with the DSP Factory hardware, mixer components in MxTrax work in real time, even when all 16 tracks are playing. There is no visible or audible latency between a movement and the expected result. Using the mouse, you can "turn" the rotary knobs for EQ, dynamics processing, and aux sends, but you can also place the cursor in a knob's value field and drag it, which allows finer control. The volume faders, which can be grouped, move precisely, and the changes are instantaneous.

The mixer components are comfortable and easy to manipulate with the mouse, but if you enjoy a more tactile mixing experience, MxTrax supports MIDI hardware control surfaces from CM Automation (MotorMix), Mackie (HUI), and Peavey (PC 1600x). Support for hardware controllers is selected from a drop-down box in the Preferences screen; no other program settings are required. MxTrax even provides built-in support for the Yamaha 01V as an automated front end. Although it's a full-blown console, I found that the 01V serves great double duty when used to command MxTrax.

AUTOPILOTMxTrax supports automation of the mixer controls on a per-channel basis via the Automation buttons. Parameters in the DSP effects can also be automated. There are three basic modes: Write, Update, and Playback. The background color of the Automation button indicates the mode. Red is for Write mode, split green and red is for Update mode, and green is for Playback mode.

In Write mode, all of the controls for the selected channel record automation data, whether or not a control is moved. In Update mode, the mixer plays previously written automation data until you move a mixer control. The control then enters Write mode until it is released, at which point it returns to Playback mode. In Playback mode, the mixer plays previously written automation data, and new automation data cannot be recorded. I found the Automation features in MxTrax to be straightforward and simple to use.

MAKING THE CONNECTIONFor those of us who are musicians more than we are engineers, the topic of DSP Factory busing can evoke blank stares and glazed eyes. Although I'm somewhat "schematically challenged," I found signal routing in MxTrax to be foolproof because the engineers at Minnetonka have implemented a routing system that does not require an in-depth understanding of DSP Factory busing.

A right-click on the box at the bottom of each channel strip opens a list of options for connecting that input channel. You can connect an input channel to disk tracks or to physical inputs (I/O cards) such as the optional AX44 unit or the SW1000XG card. The Tracks option opens a submenu that lists the current project's audio tracks; selecting a track places its name in the Track Input box. It's especially convenient that you don't have to retype track names into each channel strip.

Selecting I/O Cards provides a submenu of the available external inputs, such as DS2416 In L, DS2416 In R, AX44 In 1 through 4, and SW1000XG In 1 through 6. Once selected, the input name appears in the Track Input box.

MxTrax also has a drag-and-drop quick-connect feature. If you place the cursor in the leftmost track area and hold down the left mouse button, the cursor changes to a silhouette of a phone plug (see Fig. 3). By dragging the phone plug to the fader area on the input channel, you can assign the track and have the track name appear at the bottom of the input channel. Happily, MxTrax takes the rocket science out of DSP Factory busing and gets the job done behind the scenes.

EASY EDITSAudio editing takes place in the Track window, where MxTrax features nondestructive editing of audio Regions. A Region is a set of start and end points in any audio track. An unedited audio track consists of a single Region from start to end. During editing, you can split that Region into multiple Regions, move it horizontally to a different time location on the track, and adjust its size to include more or less of the original audio track.

In fact, you can perform more than 50 editing operations on Regions, including loop, nudge, normalize, crossfade, insert time, delete time, gain change, and automation scrubbing. I found the Gain Change command particularly useful for adding a fraction of a decibel to boost softer passages. You can group Regions with the Group/Ungroup function and manipulate them together. That feature is handy when two or more Regions must stay locked in time.

Working with Regions is easy and intuitive. In each Region display, there are five locations where the mouse is used: the left and right Region edges, the lower-middle Region section, the upper-middle Region section, the upper-left and -right Region corners, and the edit-cursor position. For example, to trim the beginning of a Region, you position the pointer at the Region beginning. The pointer then changes to a graphic cursor with left and right arrows. Pressing the left mouse button and moving the mouse to the right trims the Region. By adjusting the Region's ends in this way, you can make a Region as small as a single audio sample or as long as the entire audio track. Performing a track fade is just as painless: simply grab the fade handles in the upper-right or -left corner of a Region and drag horizontally. Fading in or out couldn't be easier.

Crossfades are performed in MxTrax by selecting two Regions on the same track and right-clicking on one of them to open a pop-up menu. After selecting Crossfade, you simply grab one Region and move it horizontally until it overlaps the other Region. A crossfade is formed in the overlapping area.

MxTrax also provides a user-definable number of Undo levels. The default number is 100, which I found to be more than adequate.

LIGHT AND BRIGHTIn today's audio-software market, where form often comes at the expense of function, MxTrax shines brightly. Although the reviewed version lacked support for DirectX plug-ins, I found it to be a rock-solid DAW component worth serious consideration.

Anyone who has ever worked at a console will understand MxTrax right away, and the program requires no special PC optimization or tweaking, although it would be nice to have a built-in indicator to monitor CPU and disk usage.

During the review process, I didn't experience any dropouts, skipping, or latency, as I have with some "big name" multitrack audio programs running an equal number of tracks. The thoughtfully engineered user interface, ease of signal routing, custom mixer creation, and support for several hardware controllers put MxTrax at the head of the class for DSP Factory support.

Bill Boggs is a PC-network specialist in Tustin, California. He has been involved with pro-audio recording since the '70s.

Although this review covers MxTrax for the Yamaha DSP Factory, an earlier version of the program for the Digital Audio Labs V8 is also available. The differences between the two versions are primarily the result of differences in the hardware.

With the DSP Factory, the mixer you build must conform to the architecture of a Yamaha 02R digital mixer. Within that framework, you can build any mixer up to and including a full 02R. The V8, on the other hand, has no predefined mixer, and anything can be connected to anything until you've used up all of your mixer resources.

The DSP Factory has 4-band EQ, dynamics processing, and other features available on all channels. It also lets you choose 2 of 40 mono-in, stereo-out effects. The V8 comes with no hardware effects but does allow any number of third-party effects, which can be connected anywhere in the mixer, up to the DSP horsepower limit of your system.

The V8 has optional ADAT and DA-88 interfaces, both with transport control and sync. The DSP Factory has an optional ADAT interface without sync. Furthermore, the V8 has an optional SMPTE sync interface. The DSP Factory does not have sync hardware, but MxTrax can generate MIDI Time Code, and a soon-to-be-released version will be able to slave to MIDI Time Code.