It's all Quentin Tarantino's fault.

It was 1995, the midnight show of Pulp Fiction. As the end credits rolled, a quirky, captivating melody repeated, first on twangy surf guitar, then on ill-disciplined sax. Occasionally a little of the bass line would surface tantalizingly through the waves of music like a dorsal fin only to disappear again below the melody. Some weeks later the soundtrack came out on CD; the song was Surf Rider by The Lively Ones.

At that time the only musical instrument I owned was a nylon stringed classical guitar, and I had never succeeded in getting a single note out of a clarinet. I would never have believed that I would soon learn to play Surf Rider on tenor sax, transfer my guitar skills to electric bass and eventually perform Surf Rider with my very own band.

While the saxophone part was easy to figure out by ear, the bass line was not; every time I tried to focus on it, I was distracted into listening to the guitar or sax instead. It was only the discovery of the Amazing Slowdowner that allowed me to listen to and learn the bass line by temporarily banishing the other instruments.

Overview
When you are learning to play an instrument, it can be very rewarding to play along with a recorded version. However, as a learner, it's all too likely that the recording will be too fast for you.

Some turntables and cassette decks can play recordings slower than they were recorded, but anyone who has ever played a vinyl record understands the problem: if you play the record at the wrong speed, the pitch changes - it gets too high if you play the record too fast, and too low if you play the record too slow. There's no point learning a piece in the wrong key, so you have to get up to speed on your own before you can enjoy playing along with a recording.

The Amazing Slowdowner (ASD) was developed by a jazz guitarist to solve exactly this problem. You can use it to slow down recordings without changing the key. Furthermore, you can speed up or slow down as much as you like within practical limits: you are not restricted to the couple of options offered by a record player or turntable.

ASD can also keep recordings at the same speed but change the key - either by a little for tuning or a lot for transposition. Or indeed change speed and key together without the constraints imposed by analog media like records.

ASD works with tracks on CDs as well as AIFF, MP3, WAV, AAC and iTunes Music Store files on your hard disk. It can save the transformed file so that you can burn it to a new CD. The same version of ASD is available for Mac OS 8/9, Mac OS X and all versions of Windows from 95 onwards.

Setup
The setup process starts by downloading the trial version from www.ronimusic.com. The trial version of the file can read the first two tracks of a CD or the first quarter of a file.

Once you have paid the shareware fee, you receive an email containing a password and download instructions for a .dll file. No matter whether you think .dll is a windows file extension, Amazing Slowdowner needs this file to be stowed away in your system before it can be unlocked.

In Use
The whole ethos of Amazing Slowdowner is that you get to practice playing your instrument along with a recording without the usual constraints of playing at the same speed or in the same key. This is so much more enjoyable than playing on your own, and much better preparation for playing with a band. Here are some of the potential uses.

Slowing down is the most obvious application. You are trying to learn something but it's just too fast. Maybe you can't even make out all the notes. Slowing it down the old fashioned way would make it too low-pitched and lugubrious. Slow it down with ASD and the notes stretch out without changing pitch. Slowing down 10 or 20% may be enough to help you play along with a new song, whereas 100% or more may help figure out tricky runs and riffs.

So why would you speed up? Well, if you are learning to play something that's just a bit too fast for you, one of the tricks you can use is to work on playing it even faster than you need to. Eventually when you play it at the proper speed again it's easier.

Sometimes when you're playing along with a recording, you find that your perfectly tuned instrument sounds out of tune. This could be because the recording has been deliberately changed in pitch for some artistic or technical reason. It's inconvenient to change the tuning of a guitar or bass for just one song only to change it back again for all the others in your rehearsal list. It's very useful to be able to change the pitch of the recording to precisely match your instrument. ASD's pitch scrollbar moves in cents when you click on the arrows - this is about the finest pitch adjustment you can perceive.

On the other hand, your band may collectively decide to play a song in a different key than the common recordings to suit one or more members. For example the vocalist may not have the same vocal range as the original artist. With ASD you can change the pitch of the recording accurately one semitone at a time by clicking in the scrollbar.

Pitch changing up by a whole octave is a godsend for bass players, since midrange instruments and vocals usually mask bass frequencies. Sting described in an interview how he used to figure out bass lines by playing records at higher speed - for example 45 rpm instead of 33 1/3 rpm - in order to shift the pitch of the bass up a bit and shift the distracting midrange frequencies out of prominence. The trouble with this approach is twofold - as the frequency shift is not an exact factor of 2, the music ends up in a different key, and worse still it's also faster, so it's more difficult to play. With ASD you can shift up a whole octave while leaving the speed unchanged, or even slowing down the recording. The bass line is then clearly audible in the correct key and the other instruments and vocals turn into squeaking hamsters on helium - this can be alarming to other members of the household so earphones may be advised.

If this isn't good enough then ASD has some other tricks up its sleeve. Karaoke mode attempts to suppress the mid frequency range, which may improve your ability to hear what you want. There's a graphic equalizer. Finally, there's a stereo pan control, which gives some last-ditch assistance if the instrument you want to isolate is not dead center in the stereo field.

As a last example of special interest to wind players, ASD can help you play music intended for the wrong wind instrument in the right key. A note of explanation is probably necessary here for non-wind players. When a "normal" instrument plays the note that is written as C, the sound is C. When a wind instrument plays the note that is written as C, the sound, depending on the instrument, may be something else - for example, an E flat for an alto sax or a B flat for a tenor sax. So the music has to be written differently for each wind instrument in order to sound in the proper key when played. As a tenor sax player, you can read and play a bassoon concerto but it will sound in the wrong key if you try to play it with a recording. With ASD you can change the recording to suit your instrument and the available music.

All these miracles and more are possible with ASD. What's it like to use?

I tend to work with ASD and iTunes running at the same time. It's a good idea not to actually play a song with each program at the same time - especially the same song, especially at different pitch / speed settings. I blame the only time I really crashed OS X on failure to observe this commonsense principle.

However, since ASD is not a plug-in to iTunes and does not access the iTunes library like iPhoto and iMovie do, you need to find the song you want in iTunes and then drag it into ASD's song list. Alternatively you can command-R the song in iTunes to show its file and then drag that to the ASD icon. ASD keeps its own list of songs you are working on and stores up to 10 presets for each song. The presets store position, speed and pitch information; you can name them for the part of the song they refer to and call them up with a single keypress.

ASD doesn't use the same keyboard shortcuts as Garageband and iMovie for manipulating the timeline. However it does have a preference for how you use the spacebar during playback - you can set it to either pause and continue or always go back to the beginning. There are also useful settings for how much intro you get before the point you are trying to listen to. ASD has a host of keyboard shortcuts, many arranged on the numeric keypad. This is important because it's far quicker to hit a key on the keyboard than to find the mouse and move it to a target.

The only issue with the user interface is the three timelines - one for the playhead, one for the loop start point and one for the loop end point. They are woven together in a web of logic. Try to drag the start point beyond the end point and the end point has to move too. Try to drag the end point before the start point and it will spring back to a position one second after the start point. I really think all this ought to be possible with one timeline, as Garageband and iMovie ably demonstrate.

Summary
The Amazing Slowdowner is an essential tool for any musician using Mac OS X, Mac OS 9 or Windows. It allows you to make music faster or slower without changing its pitch, and to change the pitch of music without changing its speed. These functions have a variety of applications including learning complex passages, isolating masked instruments from a mix and transposing music into different keys to suit different performers.

ASD works with music on CDs and files on your hard disk in all common Mac formats including music purchased from the iTunes music store. ASD is not an iTunes plug-in, does not link to the iTunes library as iLife programs do, and in general does not follow the user interface conventions of iMovie and Garageband. Nevertheless it is easy to import music from iTunes into ASD and it has many keyboard shortcuts which make it easy to use while you are playing your musical instrument.

Pros

• Changes pitch and speed independently
• Special functions help to isolate instruments
• Loop function
• Drag and drop from iTunes
• Works with iTunes music store files

Cons

• No integration with iTunes
• Some differences from standards used by Apple timeline programs
• Multiple timelines may be confusing
• May disturb other members of your household unless you use headphones

Overall Rating

4 1/2 out of 5 Mice