The idea of a truly portable DAW application has obvious appeal, especially when that application costs as little as EnergyXT. But can you really carry everything you need to make music on a USB Flash drive?
Available for some time as a download from the developers' web site, EnergyXT has recently graduated to a fully fledged retail package. As usual, this consists of a large and largely empty box containing an installation CD. More unusually, a USB Flash drive is also included (2GB in the 'Plus' version, 1GB otherwise), on which the software is installed and from which it may be run. It's available for Windows, Mac OS and GNU/Linux, and has a basic minimum system requirement: 512MB RAM and a 1.4GHz processor on PCs, or any Intel or Power PC CPU on a Mac.
Reading the promotional copy, you get the impression that the developers aren't entirely sure how to market EnergyXT. It's described as a "digital audio workstation” and an "ultra portable studio”, while at the same time promising to "extend your current DAW” and work comfortably alongside "any professional environment such as Logic or Pro Tools”. It can "neatly host ReWire compatible applications such as Reason and Ableton Live”, and can itself be loaded "as a VST plug‑in within any VST host software of your choice (Windows only)”.
In reality, EnergyXT is a relatively simple audio recording, MIDI sequencing and plug‑in hosting application, and is affordable at $220 for the boxed version or 59 Euros on-line. It does, however, have some unique features, and is the first commercially available audio recording package to conform to the 'portable application' paradigm (see box).
The main pane in the EnergyXT window can be switched between three different views: Modular, Sequencer and Mixer. Sequencer adheres to the de facto standard that has evolved for sequencer and DAW applications: if you've ever worked with Cubase, Ableton Live or FL Studio, it will all seem familiar. Tracks containing MIDI parts or audio recordings run from left to right across the larger part of the application window. At the left, each track has an editable name field, and buttons to mute or solo track output. To the left of that, a browser pane allows searches for project files, plug‑ins, audio content and so on.
Each track can be expanded, allowing a more detailed view of its contents without leaving the main sequencer overview. 'Normal' MIDI instrument tracks expand to show a piano‑roll display of note data (double‑clicking adds notes, right‑clicking deletes them), with velocity, pitch‑bend, aftertouch and other controllers displayed in a strip below. All the usual recording, quantising and step-programming functions are provided. An event-list view of all note and controller data is also available, allowing further control. Tracks using EnergyXT's built‑in drum-machine instrument (see the 'Instruments Included' box) display an intuitive grid editor for drum patterns, where double and right clicks work in the same way.
Audio tracks show a simple waveform overview, where selections can be dragged and simple destructive editing processes applied. Edit functions include normalise, delete, reverse, and fades in and out. There's also an automatic 'beat‑slicing' function, and a high‑quality time‑stretch. Multiple tracks can be recorded simultaneously.
MIDI instrument and audio parts can be double‑clicked and opened in dedicated editor windows, allowing a little extra room for manoeuvre, although it's very often possible to carry out edits without needing to leave the main sequencer view.
The Mixer vew displays a fairly standard virtual mixing console, with channel strips for audio and virtual instrument tracks, each having a fader, slots for insert and send effects, a built‑in EQ, and so on. Group channels can also be added so that submixes can be created. All mixer parameters can be automated. A single channel strip can also be displayed in the Sequencer view, to the left of the track list, which updates to display the selected track's channel settings so that it isn't necessary to switch to Mixer view to make small adjustments.
The Modular view is more unusual. As its name suggests, it mimics the functionality of a modular synthesizer, allowing the different sound‑generating and ‑processing devices and plug‑ins in a project to be patched together in more or less arbitrary fashion. The modular window is reminiscent of applications like AudioMulch or Plogue Bidule, and works in a broadly similar way.
At its simplest, the Modular window provides a way to chain effects processors together to create sound‑mangling multi‑effects patches (any number of processors can be chained). The main audio and MIDI inputs also appear as modules, as do virtual instruments. Modules can be connected in series and in parallel, and an Arpeggiator MIDI effect can be patched between the MIDI input module and an instrument to generate complex variations on passing note data. The Modular view is easy to get started with, and offers an interesting alternative view of the component parts of a track.
EnergyXT supports third‑party effects and instruments in the industry‑standard VST format, and even allows VST plug‑ins to be used on Linux systems, although specially compiled versions are required. A fair selection of in‑built effects is also provided, including reverb, delay, chorus, phaser, bit crusher, a multi‑mode filter and a compressor. These are simple but work well, and together with the built‑in instruments they add up to a useful toolkit for accomplishing basic production tasks. A freeze function can be used to temporarily render plug‑in‑heavy tracks as audio, to reclaim some CPU cycles.
EnergyXT provides sensible shortcuts to make common tasks quicker and easier. Right‑clicking in empty space in the track list opens a contextual menu from which you can choose Synthesizer (which creates a MIDI track and assigns an instance of the built‑in synthesizer to it), Drum Sampler, which does likewise, only with the built‑in drum sampler, a blank Audio track, or Guitar Amp — an audio track with an amp simulator effect inserted in the mixer channel, ready for recording. A simple MIDI learn function allows external hardware controllers to be assigned to mixer and plug‑in parameters with a couple of clicks.
Overall, EnergyXT is easy to learn and use, and performs well. The application starts quickly, is relatively undemanding of system resources and feels responsive. Simple musical ideas can be outlined rapidly, and the program's modular capabilities make it a useful tool for more creative sound‑design tasks. It doesn't offer all the features of a more heavyweight sequencing package — there's no score editing or sync'ing to picture, for example, and if it's possible to program a tempo change within a song, I couldn't work out how — but it's still more than functional. While writing this review I had periodically to keep reminding myself that the whole package is available for less than the cost of a budget effect box. Given the power and flexibility on offer, EnergyXT represents very good value for money.
In an ideal world, a portable audio application could be taken just about anywhere, plugged in to just about any computer, and used right away without any need for setup or configuration. In reality, this is a fairly tall order, and there are a number of small to medium‑sized technical problems that can arise to make matters more complicated. With this in mind, I decided to start testing EnergyXT without making any special preparations, on a couple of not especially audio‑friendly computers, to see how it would bear up.
I began with my laptop, an entry‑level ASUS notebook running Windows Vista Home Basic. I plugged in the EnergyXT Flash drive, which was duly recognised, and waited while Windows set about installing a device driver. A few moments later I was informed that the device was ready to use. Double‑clicking the drive icon, I navigated to the 'EnergyXT 2.5 for Windows' folder, and double‑clicked the executable file inside. EnergyXT launched and prompted me to register the software.
Registration requires a serial number, which is printed on the CD sleeve, and an Internet connection. On‑line activation is sometimes made a tediously drawn‑out process, but in the case of EnergyXT it took only seconds to complete. EnergyXT stores its activation in a single file called 'xt.lck' in the program directory (that is, on the USB flash drive when running portably). This means you can carry your activation with you wherever you go, and won't be constantly prompted to reactivate. You can also make a backup copy, to insure against accidental corruption. (Application preferences are also saved on the flash drive, in a '.ini' file.)
For some reason, the Windows, Linux and Mac versions of the program store their own copy of the 'xt.lck' file in their own sub‑directories, which means that you either have to activate each one in turn, or activate one and then copy the 'xt.lck' file to the other sub‑directories. A better solution for portable use would be to store a single activation file in one place, accessible to all three versions, so that activating one activated them all.
Once the application was up and running, I loaded the supplied demo project and clicked the Play button. The results were... not impressive. The sound was choppy and distorted, and generally unsatisfactory. To be fair, this was while using the default DirectSound driver and my laptop's built‑in audio hardware, with EnergyXT's default buffer size of 1024 samples. Increasing the buffer size gradually improved things, until I finally arrived at clean and stutter‑free playback. Switching to an ASIO device driver, if one is available on the machine you're plugged into, improves performance dramatically, as you would expect.
Next, I quit the application and tried to remove EnergyXT's USB Flash drive. None of Windows' usual methods for 'stopping' or 'safely removing' the drive would work, and after several attempts the machine stopped responding. I left it to think things over for 20 minutes, but in the end I had to forcibly shut down by leaning on the power button. A bit worrying, but fortunately it proved to be a one‑off. After a reboot the problem disappeared, and on every successive occasion the Flash drive mounted and unmounted cleanly.
For the next test I plugged EnergyXT into a USB port on the elderly beige box that sits under my desk running Ubuntu GNU/Linux and doing useful work as a print server and backup store. It's an old Dell machine from before the days of USB 2.0, and very definitely not a high‑end audio workstation.
To be frank, I wasn't expecting EnergyXT to do much more under these conditions than fail colourfully, but in fact it worked, after a fashion. The application ran, and I was able to load the demo project as before. However, as before, audio performance was very poor: choppy and distorted. I wondered at first if this might be something to do with the lower bandwidth of the older machine's USB 1.1 port, but copying the application to my home folder on the hard disk and running it from there yielded the same results. In the end a certain amount of tweaking of my Ubuntu system configuration (which I won't attempt to document here) was required to get things working properly. Once up and running, I was surprised how well the program did run, in spite of the inadequate hardware.
My admittedly simple tests revealed a not‑too‑surprising fact about portable applications and their viability for audio: more than text editors or web browsers, the usefulness of audio applications depends on the hardware and software configuration of the machine you're working with. If a computer you encounter in the field isn't quite up to the job, EnergyXT may not be usable. If you're plugging into a computer that's routinely used for audio (at a studio, for example), with a high‑quality audio interface and ASIO driver, there's a good chance EnergyXT will work well 'out of the box'. A more general‑purpose computer, perhaps in an environment where changes to the operating system configuration are not permitted, may have problems.
It's difficult to predict in advance exactly what kind of performance you can expect from EnergyXT with different computers, but common sense is a pretty reliable guide. Older machines with USB 1.1 ports should be approached with caution, and recording directly to the USB drive should be avoided unless there is no other option. With more recent hardware you can expect better performance — although, in any case, if a project relies on intensive multitrack audio recording and playback, a conventional hard disk installation will always be preferable, since it reduces the likelihood of take‑spoiling technical mishaps.
Equivocation aside, during my own tests, with EnergyXT's Flash drive attached to my laptop's USB 2.0 port, I ran into very few problems. Recording directly to a folder on the USB drive, I was usually able to overdub six or eight tracks of audio alongside a basic virtual instrument backing programmed using the built‑in instruments, without encountering any stuttering, drop‑outs or similar problems. Beyond that point, in the interests of reliability, I'd probably want to be recording to hard disk anyway — but it might be possible to push it further.
Overall, EnergyXT's developers have succeeded in adapting a powerful, professional‑quality audio application to the 'portable application' paradigm as well as could reasonably be expected, and have also done an excellent job of making the same functionality available on different computing platforms.
As USB Flash drives have become bigger, cheaper and near‑ubiquitous, a trend for 'portable' applications has begun to emerge. A portable application is defined as one that installs all its essential files on a removable USB device, which can be run from that device without requiring a hard disk installation, and which leaves no configuration files or user data behind after the device is removed. Portable applications have earned a following among students and employees wanting to make use of software that's not available (or not allowed) on their campus or workplace systems.
A version of the Firefox web browser was among the first portable applications to be developed, followed by versions of popular word processors, image editors and other useful utilities — see www.portableapps.com for more examples. Portable audio software has been slower to catch on, although a portable version of the open‑source Audacity editor does exist. EnergyXT is, to the best of my knowledge, the first commercially available DAW package to be offered in portable form.
At first glance, portable audio software appears to be an excellent idea: musicians travelling to gigs or rehearsal rooms, or to a bandmate's house for practice, need not bring their own computer equipment with them. Instead, a pocket‑sized stick containing the application and project files can be taken and plugged into whatever machine awaits at the other end. Which sounds good in theory, and is certainly possible — albeit with a few technical caveats to be borne in mind.
First, any computer you use must be running an operating system compatible with the software on the USB drive. EnergyXT is off to a flying start here, offering, as it does, versions for Windows, Mac OS and GNU/Linux. The minimum hardware requirements must also be met, and if you rely on any particular effect or instrument plug‑ins, these must be compatible too (which is by no means guaranteed, especially if you're moving between operating systems).
If you're planning to run the application directly from the USB device, you should also be aware that its performance will be limited by the maximum bandwidth available on the USB bus. The USB 2.0 specification (the standard on all recent computers) allows 480Mbit/s in theory, although potentially rather less than that if multiple USB devices such as audio and MIDI interfaces are in use on the same bus. The EnergyXT manual notes that intensive audio streaming requires significant throughput of data, and warns that this may not always be practical when running from a USB 2.0 device. Furthermore, older machines may only have hardware supporting USB 1.1, where the maximum bandwidth is 12Mbit/s, which will only exacerbate the problem.
Like any self‑respecting DAW application, EnergyXT supports third‑party VST instrument plug‑ins. However, it also includes two of its own: a synthesizer and a drum machine. The former combines a 'phase modulation' synthesis engine and sample‑playback capabilities, while the latter is a more basic drum sampler. Both present simple user interfaces that are functional almost to the point of being bland, but are also commendably clear.
Although not visually ornate, the instruments are easy and intuitive to use, and ideal for sketching out musical ideas quickly. A fair library of presets is provided for the synth, including some good analogue‑style basses and warm pads. It's potentially a lot more versatile than that, however, especially taking its sample‑playback capabilities into account. The drum sampler allows samples to be loaded by simply dragging and dropping, and the volume, panning, tuning and filter settings of each drum pad can be adjusted independently.
Being closely integrated with the application, EnergyXT's built‑in instruments are especially useful when working with the portable version on two or more machines running different operating systems. While third‑party instruments may suffer incompatibilities or present copy‑protection or activation problems, the built‑in instruments can be relied upon to work the same on any machine where EnergyXT will run.
Despite providing something pretty close to a complete, self‑contained package, EnergyXT's developers have also attempted to build in interoperability for users who want to use the application in conjunction with other DAW software.
Not content with being a VST plug‑in host, EnergyXT is also supplied in a special version that can itself be loaded as VST plug‑in. In fact there are two versions: one configured as a VST Instrument, the other as an effect. The VST version does not replicate all the functionality of the stand‑alone application, instead focusing on the modular window, allowing freely patchable audio and MIDI plug‑in chains to be created and put to work in other host applications. This is certainly an interesting addition to the package, although it's also one of the few areas in which cross‑platform compatibility is wanting: EnergyXT VST is available for Windows only.
Windows and Mac OS users (Linux users are out of luck) who buy the 'Plus' version of EnergyXT 2.5 can also take advantage of ReWire compatibility. A special ReWire VST plug‑in is provided, which allows EnergyXT to exchange streams of audio (one stereo and six mono channels) and MIDI data with other ReWire‑capable applications, such as Reason or Ableton Live (for instance, the output of Reason instruments can be recorded onto audio tracks in EnergyXT). Only one instance of the ReWire plug‑in can be used at any time, although that's still enough functionality to be useful.