Phone Tag

Apr 1, 2007 12:00 PM, By Steve Ouimette

Lower Your Voices

After finishing the file cleanup and loop, the next step was to create the 4-voice GM version. Using the 16-voice version as the template, I began the task of reducing the theme to four voices. Because the melody was using only one voice, there were three voices available to finish the arrangement. The bass track also used one voice, so it stayed in as well. With only two voices left, I employed a technique that allowed me to squeeze an apparent three voices out of the drums. Inspired by Charlie Watts's technique of never hitting the high hat and snare simultaneously, I simply removed the high-hat notes whenever the snare was hit. Because both the hat and snare were high-frequency sounds, it was a great way to keep the groove going, and the hat's absence was barely noticeable.

Making the mono version required a bit of extra thought and work. I used the 4-voice GM version as the working template and employed a few techniques to make a convincing 1-voice track. Because the original theme began with drums and bass, there would have been a lot of empty space had the file been reduced to just the melody track. The best way to represent the rhythm was to use the bass track up until the melody came in. I erased all the bass notes when the melody was playing, and when the melody took a break, I used the bass again to fill in the gap. This created a pseudo rhythm track while still using only one voice.

Yamaha Considerations

The Yamaha SMAF format works a bit differently than standard 16-voice General MIDI in that each different drum sound is counted as one voice of polyphony. This means a kick, snare, and high hat will count as three voices, even if they are not played simultaneously. Because I had used seven different drum sounds in the 16-voice GM version, I had to be careful not to go over the 16-voice limit. As a result, I ended up combining the two toms into a single tom hit, which reduced the track polyphony to six. With those changes, the SMAF file preparation was complete, and all the files were ready to go for the conversion stage.

The next step was to convert the SMAF and Nokia tracks into their respective formats (the 4- and 16-voice GM files were already in their final format). Many specialized tools are available for file format conversion and creation, but the one I chose to use on this project was Unwiredtec's Ringtone Creator. Ringtone Creator allows for conversion to many note-based and PCM formats from a variety of sources (see Fig. 2). The conversion process involved simply loading the prepared file, selecting the appropriate output format, and clicking on a few buttons. I did this for both the SMAF- and Nokia-prepared files and ended up with files that could be played on their respective handsets.

Playback Testing

Playback testing for mobile is very much like mixing and mastering at the same time. Listening to the files on real handsets allowed me to tweak the voicing and balance of the instruments to sound best for each format. Because there was no single handset that could play all four of the formats for this project, I ended up using several to test on. The files were loaded onto the handsets through a data cable using various software and hardware combinations. Although there are other ways to transfer the data (Bluetooth or WAP, for example), all of the phones were set up for data-cable transfers. For the 4- and 16-voice GM versions, I used Motorola Phone Tools and loaded the files onto a Motorola Razr. For the Yamaha SMAF format, I opted to use the Yamaha MA2 hardware developer box with a dummy phone connected to it (see Fig. 3). Finally, the Nokia format was loaded onto a Nokia 6630 phone using Nokia's PC Suite.

Listening to the GM versions, I noticed right away that the bass was inaudible. It was also clear that the high hat was far louder than it had sounded when playing back on my PC monitors. The solution was to raise the bass part an octave and reduce the Velocity of the high hats. After going back and forth a few times, I found the balance to work great for both GM versions on the Razr. Knowing that each handset would sound different, I opted to load the GM versions onto a variety of handsets in my collection. After a few more minor tweaks, the files sounded good across the different phones (see Web Clip 1).

The same process was applied to the SMAF and Nokia formats until they sounded right to my ears. Yamaha's hardware developers tools allow for extensive editing of the FM voices, so I spent a good deal of time crafting the actual sounds. An added bonus of the SMAF format is that it provides uniform playback across MA2-enabled phones (see Web Clip 2). The only difference is in the speaker and molding of various handsets.

The most difficult format to get a good-quality sound from was the mono Nokia OTT. OTT was created more than a decade ago and was not designed to play ringtones the way we know them now. The familiar Nokia ringtone that we've all heard showcases the sound of the format, which can be very piercing but functional. Most of my time was spent making sure the notes were in a pleasing octave range and not overly loud (see Web Clip 3). With that last bit of tweaking, I was finished and ready to deliver the files to the client.

Who's Calling?

Working on this project was very much like writing a polyphonic ringtone. At this time the technology is growing fast, so expect to see a lot more in the way of interactive soundtracks, multiple tracks of streaming audio, and PCM sound in the future. These trends have already developed in Japan and Europe, and some of the game companies I work with are now using highly advanced engines for mobile games.

Still, there will always be projects that have small audio budgets, so the need to squeeze the most out of every byte will remain for the foreseeable future. It's also a fun and rewarding challenge to work under tight limitations — it forces creative thinking. If done properly, your music can be a joy to hear when playing in a game, even if it's coming through a 10 mm handset speaker.

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Steve Ouimette runs 8th Wonder Productions (www.8thwonderproductions.com), whose main business is creating soundtracks for mobile, console, and PC games. You can reach him at steve@8thwonderproductions.com.

Manufacturer Contacts

Motorola http://direct.motorola.com/Hellomoto/nss/productresource.asp?PhoneModel=mpt

Nokia http://europe.nokia.com/A4144903

Unwiredtec www.ringtonecreator.info

Yamaha http://smaf-yamaha.com