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06/07/2003: Acid XPress [>> Go]

    Acid XPress from Sonic Foundry is a unique kind of music creation tool. Rather than hitting keys on a virtual keyboard or drawing notes on virtual lined paper, Acid lets you combine small loops or samples of drum beats, guitar riffs, vocals, and other snippits of music and sounds to create original music. The resulting songs depend a lot on the types of loops you have to work with and your creativity, but with the right source material (which is, unfortunately, difficult to obtain for free), you can create anything from country/bluegrass to heavy metal music, and then share it with friends and family. It's unlikely you'll get a recording contract with the music you create with Acid XPress, but it can be a lot of fun coming up with new compositions and playing around with new sounds.

    Acid XPress primarily uses files called "loops". These are short snippits of music or sound that are specially created to be able to be repeated over and over to create a longer piece of a song. Think of the drum line from some song you've heard recently; for most of the song, the drums probably just repeat themselves over and over, like dum-dum-DUM-da-da-dum--dum-dum-DUM-da-da-dum... A "loop" file would contain just one of the "dum-dum-DUM-da-da-dum" riffs, so that if you were to play it over and over ("loop" it) it would sound like the drum line for the entire song. This same idea can be applied to guitars, horns, piano/keyboards, and just about any other kind of musical instrument or sound. While you certainly can't be as creative using these pre-packaged loops as you could if you were conducting an entire orchestra, for me (and probably a lot of other people) this kind of constrained creativity is actually better (than, say, composing songs using MIDI) because I don't feel so overwhelmed with choices. To compare this to drawing/painting, Acid XPress is like starting with a pile of creative stickers that you're going to use to create a picture - you're somewhat limited by the stickers you happen to have, but you can still put them together in creative and original ways, and for some people, it might be easier to make a picture that way than to sit down with a blank sheet of paper and a box of watercolors and trying to decide "where do I begin?".

    Acid XPress' interface, shown above, lists your active loop/sound files down the left-hand side (Acid XPress allows up to 10 different loops in a single song). The right-hand side is a timetable, starting at zero seconds at the left and increasing to the right. You store loop files on your hard drive, browse to them within the Acid XPress screen, then add them to your song by dragging them from the bottom of the screen to the top. Once a loop is in your song, you need to specify at what point during the song it will play, and how many times you want it to repeat itself. "Composing" is more visual than aural; you have a couple of tools to help you diagram out your music, including a "pencil", a "paintbrush", and an "eraser". To add music to your song, select the pencil or the paintbrush, click at the time you want the loop to begin, and drag to the right until you want the loop to end. You can make a loop start and stop throughout the song to alternate with another loop or to add variety, and you can even adjust the pitch of individual sections of a loop to make it sound higher or lower at certain points. There is a set of play/pause/stop buttons at the bottom of the list of loops that let you preview your song to see how it sounds, and while previewing the song you can turn individual loops on or off to see whether the song sounds better with or without them (without needing to remove the loop altogether). The bottom part of the Acid XPress screen can be switched between an explorer pane (to let you browse your computer for loop files) and a loop information pane. In the explorer pane, clicking once on a loop file (which are really just .WAV files, though files provided by Sonic Foundry contain extra information about the loop, such as its beats-per-minute and key) will play it for you, so you can see what a loop sounds like before you add it to your song. Song files are stored in Acid's .ACD format (which keeps track of which loops the song uses and what their layout is), but when you are satisfied that a song is "done" and want to share it with others, you can use the "Render" option under the "File" menu to save the song as an MP3 file (limit of 20 in XPress) or a .WMA file (Windows Audio, limited to 56K bitrate, i.e. not CD-quality). You can also sign up for a free account at and publish your song to the AcidPlanet online community for other people to listen to. And fortunately, Sonic Foundry has provided some tutorials for using Acid to get you started (start with ACID 2.0: Getting Started with ACID, then check out ACID 3.0: Exploring the ACID Interface and ACID 2.0: Basic Editing in ACID). Here is a song I created in Acid XPress just for this review (MP3, 2MB), using 5 different loop files.

    As I mentioned before, in Acid XPress you combine loop files to make your own original songs. While you can use any audio recording software to create .WAV files and import them into Acid XPress, creating "loopable" files is a much more difficult task because it requires the loop's starting and ending audio to be synchronized. Sonic Foundry sells dozens of loop libraries which contain hundreds of loops in a particular genre for around $60 per CD, which is one solution, but I wouldn't recommend paying that much money for a loop CD if you're only interested in using Acid XPress. There are some other options available, but you're at the mercy of what loops you can find. When you download, install, and register Acid XPress, under the "File" menu the option "Get Media from the Web" will take you to a page where you can download a couple of sample songs (which include a few loop files and a .ACD file that uses the loops in a complete song). Sonic Foundry's releases a free loop and song file package (called an "8Pack", they usually contain between 8 and 10 loop files) every week, but you have to download the packs each week - old 8Packs are not available for download. (This is what I do, but I've been doing it for a long time so I've amassed quite a collection of various loop files.) Lastly, you can try to find loops and other .WAV files on the Internet. If you plan on doing anything with your songs besides listening to them yourself, be aware of copyright laws and what pieces of other songs, movies, TV-shows, etc., you include in your own songs. Yahoo has a Samples and Loops category with a number of Web sites, some of which have some free downloadable music loops; has a similar category you can look through as well. There is an Acid Loops Webring that has some Web sites offering free loop files. Hopefully some combination of these can get you enough loops to get started playing around with your own original compositions in Acid XPress.

    Acid XPress is a pared-down version of Sonic Foundry's fuller-featured Acid family of products, and it reminds you of that fact if you try to do something that is only available in the full Acid product. XPress is particularly hampered by not letting you create high-quality output files to share with other people - you're limited to generating 20 MP3 files, and after that you can only create 56k bitrate .WMA files (which will not sound as good as the 128k MP3 files you were able to make before). I find it very annoying that the XPress version of Acid doesn't just disable features that aren't available, like exporting to .WAV files - they purposely leave all the features visible so that when you try something that's not usable in XPress, it reminds you that you should buy the full version of Acid. I think that's kind of cheap, since it makes XPress feel like a promotional tool rather than a piece of free (if severely hampered) software. Even though the marketing messages are annoying, the base functionality of creating original songs (if you can find or create decent loop files) works without shelling out the money for the full version of Acid, so I think XPress still has value as a stand-alone piece of free software. I think it might be especially fun for children to play around with because you can listen to your song as you create it, and it really gets you thinking about what kinds of music samples go well with each other. I, unfortunately, was not satisfied with XPress, and eventually upgraded to the full version of Acid (not Acid Pro, just Acid, which was cheaper), but unless you really get into creating your own music, XPress offers enough tools to keep simple composers happy.

©2019 Tyler Chambers