Steinberg Time Bandit

Steinberg's Time Bandit is a Mac software package for processing Sound Designer II files off‑line, using sophisticated time stretch and pitch shift algorithms. Long‑time Sound Designer II user Paul White couldn't wait to get it home...

Digidesign's Sound Designer II is arguably the most popular stereo editing package currently doing the rounds, but its importance in the greater scheme of things goes deeper than that. Both Cubase Audio and Notator Logic Audio (Mac) are compatible with the Sound Designer II file format, which means that sounds recorded within these programs can be processed using Sound Designer II (with any of its 'plug in' accessories if available), or any third‑party utility capable of working with SDII files. Furthermore, many sample editing programs are compatible with SDII files, which opens up new avenues for serious sample editing and post‑processing.

The SDII editing software includes a pitch shift/time shift function, and for relatively small shifts of not more than a couple of percent, most people find it quite adequate. But Steinberg's Time Bandit is being pitched at those who demand the best possible audio quality or a greater degree of shift.

Time Bandit is a stand‑alone program, which means that you can't access it directly from within an 'audio' sequencer or even from within SDII. Any sound file (mono or stereo) to be treated must be opened in Time Bandit which, after processing, saves a modified version of the original file. Only whole sound files can be processed and, because the program insists on leaving the original file intact, you have to ensure that you have enough disk space to complete the task.

Installing the program is simple, courtesy of the included installer program, but you have to plug in the ADB dongle (in series with the mouse or keyboard) in order to make the program run. My Mac system currently has so many dongles wired in series that it looks like a set of worry beads! The program is said to run on any 020, 030 or 040 Mac though, because of the intense nature of the processing, one of the faster Macs is strongly recommended. According to the manual, a maths co‑processor doesn't make Time Bandit run any faster.

How It Works

Time Bandit's operating window is rather like any other Mac window and it can show several sound files at once — pretty much like the contents of any other folder. The main difference is that you can't drag a file directly to the Trash can — you have to deliberately delete it. Graphic icons show whether the file is mono or stereo, and three icon/buttons deal with the main functions of the program. The first button loads sound files into the session window, while the remaining two select either time or pitch manipulation. On‑line Help is also supported, though the manual is so short that this shouldn't be needed very often.

Sound files may be played back via Digidesign hardware such as Sound Tools or Pro Tools cards, though low resolution playback via the Mac speaker is also possible. A rough preview of the end result of the intended processing is also possible via the Mac's speaker, but the manual points out that this is very approximate and is not indicative of the quality of the finally processed file.

Having selected the operation you want to carry out on the file, there are a few decisions to make in the Options menu. The major decision is the choice of Normal or Highest Quality processing mode, though on speaking to Steinberg, they suggest that Normal mode is quite adequate for most material, especially if the range of pitch or time change is relatively small. Highest Quality mode uses rather more complex algorithms and, as expected, takes longer to process.

Normally, Time Bandit is restricted to a stretch range of plus or minus 25%, which in itself is far greater than would normally be needed, but by switching to Effect mode, it is possible to go much further. Unlike hardware pitch shifters, which usually apply the same algorithm to everything they process, Time Bandit first performs a Fast Fourier Transform analysis of the file and uses this to create a set of instructions telling the software what type of processing to apply to different parts of the soundfile. Essentially, each soundfile is broken down into short blocks and each block processed according to its characteristics. Steinberg call the analysis stage pre‑processing, and as this is a fairly time‑consuming part of the operation, there is an option to select several files for pre‑processing while you go out for a curry. I have to say at this point that if you are working on an album‑length file using an 020 Mac, you'll almost certainly have time to fly to India for the curry and still get back before it's done!

Time Stretch

The Time Stretch window is relatively self explanatory, with a virtual fader controlling the degree of stretch or compression. If you're working to film, it's also possible to determine the start and stop time of the file by SMPTE location. For musical users, there's a box that allows the current tempo to be inserted and a further box where the destination tempo can be entered. Both the original and destination file length are displayed.

Because different types of material require different approaches to processing, there's a further fader which allows you to weight the algorithm in favour of retaining the greatest rhythmic accuracy or the best sound accuracy. If you're working on a stereo file, this should be noted in the Options box. For pop music, a setting of +1 in favour of rhythmic accuracy might be more suitable, whereas a speech recording might benefit from a slight weighting in favour of sound accuracy. After that, it's just a matter of pressing the Process button, and if you haven't already pre‑processed the file, that is taken care of first. A Mac‑style progress box is displayed while all this is going on, and a grey bar creeps along this box with agonising slowness!

Pitch Shift

The pitch shift window shows a graphic representation of a keyboard; pitch shift is applied in units of semitones and cents. In addition to conventional pitch shifting, it's also possible to create multiple harmonies, turning a single note into a chord. While this may be of limited use when processing complete song files, it may well be useful when editing samples. Again, selecting Effects mode increases the range of pitch shift available. Transposing is normally possible up to +/‑16 semitones, but in effects mode, this is extended to plus +/‑59 semitones. The greater the shift, the more unnatural the result is likely to sound, which is why these extreme shifts are usually reserved for special effects.

When editing samples which are nominally one note, there is an option for scanning the file to find its exact pitch, which is an ideal way of correcting out‑of‑tune recordings or fine‑tuning samples. The keyboard may be used to enter intervals (via the mouse) but is also used to input chords for multi‑harmony creation. The root note is shown in dark grey and up to 15 other keys can be selected to determine the intervals in the new chord. A check function works out the name of the chord for you and even allows you to play it back using a default sound, just to make sure the musical result is what you were after.

The Results

Most time shifting operations involve relatively low percentage changes — for example, to add another bpm to a 120bpm song involves a change of less than 1%. In cases like these, Time Bandit performs flawlessly, though I have to be honest and say that I can't hear any real difference between Normal and Highest Quality mode in such situations — indeed, the time stretch facility in Sound Designer II sounds pretty good at these low levels of shift too.

If the time and pitch shifting options already available in Sound Designer II are not good enough for your needs, Time Bandit is about the only viable option without bringing in a dedicated hardware processor.

A rather more demanding test, involving the full 25% time stretch, left the finished file sounding just a touch grainy and fluttery in parts, and though I think you might get away with it when processing individual instruments in a multitrack mix, I don't feel the quality is adequate for processing stereo masters. Highest Quality mode fared slightly better, but I still didn't feel quite comfortable with the end result. In reality, I can't imagine under what circumstance you'd want to compress or expand a file to that extreme a degree, but for changes of up to 3% or so, I'd feel fairly confident about treating stereo pop mixes or voice‑overs using Time Bandit.

Less impressive is the time the processing takes to work, especially on my ageing 030 IIcx. No doubt a fast Quadra would reduce the time considerably, but my 22‑second test file took around 10 minutes to pre‑process and then almost a further 10 to process in Normal mode. Running the test again in Highest Quality mode took around 45 minutes to process though, thankfully, the software didn't insist on running through the pre‑processing part again.

In pitch shift mode, the calculation time seemed to be roughly the same and, once again, the end result was impressive — even a five‑semitone shift processed in Normal mode sounded smooth enough to be usable. As expected, processing a multiple harmony took longer — three or four times longer in this case — but again, the result was surprisingly usable. When processing complete mixes containing vocals, the end result loses a little of its intelligibility when you add multiple harmonies, and starts to sound rather 'vocoded'.

Summary

No pitch shifting or time compression system is perfect, because what such systems set out to achieve involves all sorts of compromises, but I feel that Time Bandit produces results which stand comparison with some of the best systems around. For those who already have a Sound Tools or Pro Tools system, adding Time Bandit isn't a particularly expensive option, though I do feel the system is unrealistically slow when run on all but the fastest of Macs.

The user interface is exceptionally clear and straightforward, though the fact that you can only process complete soundfiles may mean a little juggling in Sound Designer before you can go into Time Bandit for processing. For example, if you want to correct a flat note in a vocal track, the track would first have to be broken up into regions so as to isolate the offending part, then the regions would have to be reassembled in a playlist. A new playlist containing only the item to be processed would also have to be created and then saved as a soundfile using the 'Save Playlist as Soundfile' option within SDII. After processing the file in Time Bandit, you would then need to reinsert it into the original playlist instead of the original, out‑of‑tune part. In this respect, certain pitch shifting jobs would have been easier if Time Bandit also operated as a Sound Designer 'plug in', so that selected regions could be processed directly.

Ultimately, if the time and pitch shifting options already available in Sound Designer II are not good enough for your needs, Time Bandit is about the only viable option without bringing in a dedicated hardware processor. Its algorithms do allow you to make larger changes with less noticeable side effects than SDII's own facilities, and the only penalty, as already stated, is that of processing time. If you're looking for a cast‑iron excuse to upgrade to a Quadra, Time Bandit could be just what you're looking for!