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Bitheadz Phrazer

Loop Composition Tool By Derek Johnson & Debbie Poyser
Published April 2001

The whole works: Event window to the right, master controls to the left, Event Editor across the bottom. The Engine palette is floating above an area of dead screen space.The whole works: Event window to the right, master controls to the left, Event Editor across the bottom. The Engine palette is floating above an area of dead screen space.

With its on‑the‑fly tempo‑matching for sample loops, Acid put a new spin on an old way of making music on the PC. Now, at last, there's a similar Mac program. Derek Johnson and Debbie Poyser try out Bitheadz' Phrazer...

In the early days of computer music, 'trackers' were a significant part of the scene. These rudimentary sample sequencers typically offered four to eight tracks on which snippets of low‑bandwidth digital audio were arranged to create 'songs'. As computers became more capable, and sequencers as we now know them began to establish their dominance, trackers fell from favour.

Fast‑forward to the late '90s, and sample‑based, cut‑up music dominates the airwaves, more and more people own powerful home computers, and DJs seek ways of moving from turntable to recording studio. It's fertile territory for software tools that update the ease of use of the tracker concept with the high‑quality sampled audio and sophisticated real‑time processing today's computers can handle.

Sonic Foundry must have thought so, when they released their PC 'music production tool' Acid, back in 1998. Since then, Acid has spawned a family of related programs, and it's fair to assume that the phrase‑sequencer concept has proved popular with musical PC users. Now Mac users can see if they like it too, with the advent of Bitheadz' Phrazer.

In a nutshell, Phrazer does much of what Acid does, enabling the user to build songs from sampled loops and phrases which are processed on arrival to allow their pitch and tempo to be changed freely. Effects can be added, and mixer controls allow level, pan and so on to be set. One significant difference between Phrazer and Acid is that the Bitheadz program can actually record and edit samples: Acid Pro comes with a copy of Sound Forge for sampling and editing, but has no sampling or editing routines itself.

The beauty of a program like Phrazer for people who use a lot of loops is that it takes the donkey work out of making them run together. Phrazer can insert 'split points' into samples automatically, usually on rhythmically significant peaks, to allow audio to be stretched or squashed to fit a new tempo, and pitch is also manipulated automatically. With little user input, samples originally recorded at different pitches and tempos will play back at a single master key and tempo in one Song. The processing required is not always sonically transparent, but it's fast and easy.

Phrazer Elements

From top left, to right, clockwise: The Mixer palette, offering level controls, pan pots and bar‑graph metering for each Phrazer track; the Files palette, from which any sample on a drive attached to the host computer can be dragged; the Tools palette, offering instant mouse access to a handful of editing and control functions; the Transport palette, with tape‑like transport controls and 'record‑to‑disk' icon; the MIDI palette, showing incoming MIDI activity; and the Engine palette, providing visual feedback on how hard your computer is working while running Phrazer.From top left, to right, clockwise: The Mixer palette, offering level controls, pan pots and bar‑graph metering for each Phrazer track; the Files palette, from which any sample on a drive attached to the host computer can be dragged; the Tools palette, offering instant mouse access to a handful of editing and control functions; the Transport palette, with tape‑like transport controls and 'record‑to‑disk' icon; the MIDI palette, showing incoming MIDI activity; and the Engine palette, providing visual feedback on how hard your computer is working while running Phrazer.

Phrazer's screen has several parts:

  • The Event display: Resembling the Arrange window in a MIDI + Audio sequencer, this is where samples are organised into tracks. To the left of each track is a Track Info View line, comprising basic mixing controls (Volume, Pan, Effect Send pots, track enable button) and a few track parameter settings boxes, all of which may be hidden, if desired.
  • The Event Editor: This zoomable waveform window is where samples are edited and processed, and shows their split and loop points. Automation events and effects are also edited here. The Event Editor sits permanently across the bottom of the screen, and though it's resizeable it never gets any bigger than a third of the screen height.
  • The Control Section: This area hosts Master controls that apply to a whole Song (Tempo, Volume, Balance and Effects returns), master and effects send level meters, a master key control, a fine‑tune control, and a 'beats‑per‑bar' pop‑up selector (values between 2 and 8 can be selected).
  • The Floating Palettes: The Tools palette provides transport controls plus Undo, Cut, Copy, Paste and Clear tool icons. These operations have key–command and menu–item equivalents as well, though, so the tools' usefulness is debatable! The Transport palette also provides transport controls (so why put them on the Tools palette as well?), plus a large bar/beat Song location display, and a slider for fast Song navigation. Also here are icons for the 'Record to Disk' function, which creates an AIFF audio file of the current Song on your hard disk, and the Loop function, which playback‑loops the whole Song (with a jump at the loop point!). The Files palette is for auditioning samples off hard drive without having to first import them, and allows you to drag them into the Event window. The floating Mixer palette provides a level and pan control and output meter for each track, which might be useful if you've 'hidden' the mixer controls in the Track Info View, or if the Event display is obscuring them. Finally, there's the Engine palette, which monitors CPU usage, and the MIDI palette, displaying incoming MIDI activity.

Importing, Recording & Editing Samples

This screen shows a typical effect's editable parameters in the Event Editor window, in this case a Dynamic Filter being used as send effect 1.This screen shows a typical effect's editable parameters in the Event Editor window, in this case a Dynamic Filter being used as send effect 1.

The first step in making a Song is importing or recording a sample. There are two ways of importing samples, which can be in various formats: AIFF, WAV, SDII, Bitheadz' own Unity DS1 format, and even Acid format. The first method entails dragging a sample from any attached drive, via the Files palette, into the Event display. Alternatively, you can load a sample directly into the Event Editor, which is the best plan if you know the sample will need editing. Full or partial tracks can be easily ripped and saved from audio CD, but it's not so easy to import AIFF or WAV files from CD‑ROM: they load fine, but there appears to be no way in which to save the files to disk, and any edits are temporary since the program always refers to the original sample on the CD.

There are also two methods of recording samples. You can record directly into the Event Editor — after first setting mono or stereo sampling, 8‑, 16‑ or 24‑bit recording and level — which is a good way of capturing audio off tape or CD that might need trimming. The other method is recording into a track, which is something like recording in an audio sequencer: you record‑enable a track, press the Transport palette's Record button, and name the sample you're about to capture, whereupon the program immediately goes into record — with no choice of sample rates or mono/stereo recording, no input‑level control, count‑in, or metronome! Loops already running in the track can be monitored, to provide a timing reference for the new recording. This method would suit, say, direct recording of live sung vocals over a sample‑based backing track you'd already constructed.

When a sample arrives, Phrazer asks whether to insert default split points, reminding you that they can be changed later. If you want split points inserted, it helps to know the sample's tempo, because Phrazer can't work it out; if you can't tell it, the split points may not be as accurate as they should be, and tempo‑matching may suffer. A tempo–detection element was added to the Tempo–assigning dialogue in v1.0.1, which we downloaded during the course of writing this review, but we couldn't get it to work and there's no help in the documentation. If it works out, all well and good, because a program like this really should have automatic tempo detection. (The shareware D‑Sound Pro allows you to input the number of sample bars, and calculates tempo from that and sample length.)

The insertion of split points can cause artifacts — we noticed a rhythmic juddering with some samples — but these sound appropriate to certain styles of music. However, you can choose a different 'mode' for playback of the split sample if the effect is undesirable: one mode seems to 'smooth' between split points, giving a time‑stretched effect, but this can also sound 'flanged'. The most obvious artifacts are on samples that are not drum loops.

If a sample needs editing, the Event Editor offers a fair amount of 'munging' power. Basic cropping and looping operations (whole sample or section of sample for the latter, but with no crossfading) and sophisticated DSP functions are offered: Normalise, Reverse, Change Gain, Fade, Parametric/Shelf EQ, and Flange. The last three are not just playback effects, but change the sample permanently; the shelving EQ in particular is good, especially for removing hiss from old tape recordings. Under the Editor window is a useful area hosting details about the current sample, including name, sample rate, bit depth, length and tempo (if unknown, the default label is 120bpm).

Making Tracks

Once you have a few samples on the Event display — 'split‑pointed' and edited if necessary — you're in business. The Event grid's quantise resolution is variable from a quarter‑note to four bars (it can also display in samples or time), and samples snap to grid when moved; alternatively, you can turn 'snap' off and move samples freely. Samples automatically loop to fill the length of the event box they're put in: drag the event box out as long as you like and the sample fills it, allowing very quick track creation. As many samples as desired can be placed on one track, sequentially, and there's no stated limit to track numbers, either.

As mentioned earlier, regardless of original tempo and key, all samples in a Song can play back at the Master tempo and key. Individual sample events on a track may be transposed (±12 semitones), and any that have been transposed change key relative to the rest of the Song if the Master key is changed. This transposition of individual events allows, say, a single‑note bass pattern to be shifted to create the feeling of a bass line. Incidentally, it's possible to make any track immune to Master key alterations — most obviously, to prevent drum tracks from changing pitch — by choosing the 'Split Non‑Pitched' option for interpreting split points.

The mixer controls allow real‑time track manipulation, to create extemporised performances by triggering, muting and unmuting different tracks. The 'Enable' button mutes and unmutes a track, but muting and unmuting can also be done with MIDI notes and user‑definable computer keyboard keys or function keys. (There is also an option to trigger events with MIDI notes or computer keys.) Having 'function key mappings' assigned in Mac OS's 'Keyboard' control panel interfered with the function–key method, leading to applications being launched from within Phrazer when the F‑keys were pressed! We also found the computer‑keyboard method sluggish, and on our machine it was necessary to hit the key slightly before the 'beat'.

Also tweakable in real time are the four rather tiny pots controlling Volume, Pan and the two effect sends. You'd hope that tweaks of these controls, plus mutes, and moves of the Tempo slider (calibrated 40‑200bpm), could be recorded for automation purposes, but automation doesn't come that easy — see below. What you can do is move these controls and do muting/unmuting while recording a mix to disk as audio in real time. During four attempts at this our computer crashed three times, but it worked well on the fourth.

Though there are several ways of doing real‑time mutes/unmutes, you can't transpose a track in real time from a MIDI keyboard, as you can with some hardware grooveboxes and the 'Pattern Play' features available from certain synths. This surely would be an ideal facility in such a loop/phrase‑based environment.


Aside from recording a mix to disk in real time while making changes manually, as described above, it's possible to automate track volume, pan, master volume, master tempo, master balance and effects‑send level changes. This is done by inserting 'parameter events' into tracks — not a particularly good way of handling automation. At the point where you want a parameter change such as a mute or a change of pan position to happen, Option–clicking in the Event window summons a menu, from which the required event type is selected. The event appears as a skinny vertical line at the nearest quantise grid point.

To edit the parameter event's value, you click on it — no mean feat if the display zoom value is too coarse — and it doubles in thickness. The parameter itself appears in the Event Editor. A slider lets you easily select a value for the event; be warned that a value of 'zero' (the only way to create a 'mute' event, in the case of level) reduces the skinny line to a dash of almost 'full‑stop' dimensions that's hardly visible.

Progressive changes such as level fades or gradual pans from left to right would obviously require many consecutive events to automate in this way. Bitheadz' not‑entirely‑elegant solution is a 'transition' control which ramps up or down over time to the chosen value. The user selects a transition curve type, plus a time (in ticks) over which the transition will take place. A tick isn't the most intuitive or musical of concepts, but it helps to know that 480 ticks equals one quarter–note. So, for a track to fade in over four 4/4 bars, reaching full level at bar five, you need to insert a volume event at the beginning of bar one and select a transition of 7680 ticks (16 quarter notes). People just don't tend to think like this, and it's far from spontaneous. Why didn't Bitheadz provide an automatable mixer interface, or a system of drawing level curves in the way used by virtually every MIDI + Audio sequencer?

It's also odd that one can't insert a 'transpose' event, but instead must transpose (±12 semitones) during track composition, by way of the Event Editor. So, if you'd like to use one loop for a whole Song, but want it transposed at various points, you'll have to create a new sample 'event' for each transposition. It would be much more elegant if you could create one sample event — which, as noted earlier, loops the chosen sample for its entire length — and insert 'transpose events' where required.

The situation is further complicated by events which affect not just the track they're inserted in, but the whole Song. Any changes to these — master volume, master balance or tempo — entails choosing any track of the Song, inserting the desired event at the desired location and editing it in the Editor.


The main raison d'être of a program like this is running loops and phrases automatically at the same pitch and tempo, and making mixing and matching fast and easy. Phrazer does this well. You can get an impressive track going quite quickly, and speeding up and slowing down samples in real time is great fun.

The sound quality of stretched and shifted audio varies depending on the original sample: it works very well with a lot of samples, but be prepared for the odd click, warble and split‑point‑related artifact, and even for loops that just don't quite sound in time with other loops, despite the tempo matching. What needs looking at more urgently is the lack of spontaneity of some aspects of the program — real‑time controllability and automation in particular. Bitheadz should also improve its stability (see 'Could Try Harder' box). However, we can't dispute Phrazer's usefulness for loop‑ and phrase‑based music and as a remix tool, the fact that you can sample and edit within it is great, and the DSP on offer (as befits a company so experienced in software sampling and synthesis) is impressive and lends itself to creative processing. There's nothing else quite like it for the Mac.

Computer Requirements

Bitheadz say Phrazer will run on a 200MHz PowerPC‑based Mac, with Mac OS 7.6.1, but a G3 with Mac OS 8 (or even Mac OS 9) would be a better starting point. A minimum 64Mb of RAM is required; a more realistic recommendation is 128Mb. You'll need 300Mb of free hard disk space, but add 500Mb or so to that if you want to install the program's free sample library onto your hard drive. We tested Phrazer on a 450MHz G4 (not dual‑processor) with 385Mb RAM and Digi 001 audio hardware.

All For Effects

Phrazer features thoughtfully designed effects which trade facilities against processing overhead. They comprise two global processors at the end of the signal chain, two send/return effects, and (essentially) insert effects. The last, however, can be placed as 'Effect Events' in a track — allowing you to have a different effect in every bar, if you like. However, insert effects can't be chained to create more complex processes.

The processor types on offer in each case are reverb, delay, phaser, chorus, flange, shelf and parametric EQ, compressor, filter, dynamic filter, distortion and degrade (a sample‑rate and bit‑depth reducer). The reverb is so‑so, but the remaining effects are better; delays are faithful and are tempo‑sync'able, and the more creative effects are well worth having. Effects are reasonably editable (up to six parameters each) and sound quality is good.

Could Try Harder!

Fast and clever as Phrazer is, it has rough edges. We found it crash‑prone, often during sample auditioning, importing or recording, but at other times too. Also, sometimes when the program was booted the transport wouldn't work until the Preferences box was opened and 'OK' clicked. We eventually discovered that deleting Phrazer's Preferences file also made it work again, but every time the program crashed the problem returned.

When a sample is dragged into the Event display, even if the mouse pointer is right at the start of the track the sample always drops in somewhere else and has to be dragged back. That gets tiresome pretty fast! Samples can't be dragged from one track to another, either, which is odd. You can barely tell when some of the on‑screen buttons are selected, especially the Record to Disk button in the Transport palette. The Loop button, too, is very faintly highlighted when clicked.

The program is quite mouse‑intensive: it would be great to have a Hide All/Show All option for the floating palettes, for example, and even better, keyboard shortcuts for selecting/deselecting them individually. In general, it needs more keyboard shortcuts. And there are little refinements that are well meant but not correctly implemented. For example, in the Event Editor, if you highlight a section of waveform and click on the green magnifier tool the display should zoom so that the highlighted section fills the Editor display. Instead, the section fills it and then some, so you still have to scroll to access the whole section, or un‑zoom one level. Also, the PDF manual is deeply uninformative.

None of this is fatal (except for the crashing, which may be related to our computer or setup — though it runs Pro Tools LE, Cubase VST 5, Unity DS1, Rebirth and Reason perfectly), but it puts you in a bad mood, if nothing else!

Supplied Samples

The 500‑plus Mb of sample data provided by Bitheadz consists of a ragbag of rhythmic loops, hits, bizarre textures and melodic phrases, including many that serve as demos for third party developers. Samples appear to be organised in no particular way; the aspiring DJ looking for an instantly useable, cohesive construction set of drum loops and breaks may be disappointed. There are some great, well‑recorded samples in here — including drum loops — but there seem to be rather too many texturally interesting but musically dubious impressionistic examples. At least it makes the new user go in search of his or her own samples!

Communication Studies

Phrazer is compatible with third‑party audio hardware (we used an ASIO driver to feed our Digi 001 system) and can pipe its output to other software on the same computer. At present, it works with Steinberg's Cubase VST, Digidesign's Pro Tools and Mark of the Unicorn's Digital Performer. We linked it to Pro Tools LE via DirectConnect and Cubase v5 via Rewire, though we experienced crashes during configuration. Ultimately, the results were as expected, with Phrazer's main mix and audio from up to 16 individual tracks routable to PT or Cubase mixer channels. However, it was necessary to set up an OMS Inter Application Communication buss to sync Phrazer to Pro Tools, and also, surprisingly, to achieve sync when Rewiring to Cubase. Our experience of Rewire with other applications is that it automatically provides conduits for both audio and MIDI — including sync — between connected applications. At least, this is what happens when Propellerhead's Reason and Rebirth are Rewired to Cubase.


  • Matches tempo and pitch automatically.
  • Can record and edit samples.
  • Comes with free 500Mb library.
  • Built‑in effects.


  • Cumbersome automation.
  • Some operations sluggish.
  • Crash‑prone.
  • Poor manual.


A useful phrase‑based music creation tool that could do with a bit more elegance and spontaneity.