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BIAS Peak Pro 6 XT

Stereo Editing Software For Mac OS X By Paul White
Published January 2009

The Mac's most comprehensive stereo editor has just gained a whole new set of features...

Peak 6's main waveform display, with the transport bar at the bottom showing off its new high-resolution meters.Peak 6's main waveform display, with the transport bar at the bottom showing off its new high-resolution meters.

BIAS Peak is a very well established piece of Mac-only audio software. It's designed specifically to edit mono or stereo audio files, so it should be considered as an adjunct to a conventional DAW rather than as an alternative to one. It can edit files down to single-sample precision and is widely used for mastering finished stereo mixes and for creating Red Book standard CD-Rs (with CD-TEXT, ISRC codes, and PQ subcodes) based on playlists. It is also a very practical and comprehensive sound design environment for creating and manipulating audio samples, as its use by many top sample-library creators attests. Previous versions of Peak already included sophisticated looping and tempo-analysis tools for sample-creation purposes, and they have been enhanced in this new version. Other applications include editing sound for picture and restoration.

Peak is now available in several 'weights' and with differing bundled content. Peak Pro XT 6 packs the biggest punch: as well as Peak Pro 6 itself, you get BIAS's SoundSoap 2 and SoundSoap Pro noise-reduction tools, the Reveal analysis tools, PitchCraft pitch correction, Repli-Q 'fingerprint' equaliser, the SuperFreq paragraphic EQ and the Sqweez three- and five-band compressor/limiters. Both the standard Peak Pro 6 version and Peak Pro XT 6 also come with SoundSoap LE, Reveal LE, WireTap Pro, SFX Machine LT and a one-year membership to, plus a new selection of sound effects and other audio content from Hollywood Edge, Sound Ideas, Power FX and AMG. The more affordable Peak LE, meanwhile, dispenses with some of the more advanced Peak Pro features, but is still very powerful. A table outlining the full differences between the three versions is available at This review covers the top-flight Peak Pro XT 6 package: for more on the bundled plug-ins, see the SOS reviews of BIAS's Master Perfection Suite (July 2008: /sos/jun08/articles/biasmps.htm) and SoundSoap Pro (February 2005: /sos/feb05/articles/soundsoap.htm). The LE versions are identical to the stand-alone versions, except that they can only be used within Peak and not within other DAW applications.

Peak 6 is optimised for Mac OS X 10.5 (Leopard) and for machines using Intel processors, but being 'Universal', runs just as happily on G5s or even earlier G4s, albeit less briskly. Installing, registering, and authorising Peak Pro is straightforward as long as your studio computer has an Internet connection, and as soon as you input your details and serial number, you're up and running. If your machine isn't connected to the Internet, you can transfer a generated authorisation request file to a machine that is. Each of the components of the Pro package has its own serial number and so must be authorised separately, but I found that the whole process went very smoothly.

Your Flexible Friend

Peak is already a hugely comprehensive program, so this review will concentrate mainly on the new additions and changes in version 6, though so many functions and tweaks have been added that it's very hard not to keep saying 'and another thing...'

While the interface is still very recognisably Peak in its overall style and layout, with customisable toolbars and the ability to set user colours, the new version features a new scaleable gradient 'skin' that can be changed from dark to light, or turned off, plus a new display option that BIAS call 'magnetic windows', where nearby windows automatically snap together to maximise the use of space. Auto-tiling or auto-stacking of windows is also possible, while the floating transport bar provides additional metering options (now logarithmic), and a new master monitor fader with both pre-fade and post‑fade modes.

Audio is recorded into and played back from Peak Pro 6 direct to disk, at any sample rate supported by your Core Audio‑compatible audio interface. Recording can be carried out through plug-ins, or you can apply plug-ins after recording for more conventional non-destructive processing. Editing is RAM-based, with unlimited undo. This new version makes better use of cache RAM-based editing, which goes beyond the expected cut, copy, paste and move functions (to include declicking and other repair tools), speeding up the process now that large amounts of RAM are relatively cheap; temporary files are now stored in RAM where possible, rather than being written to disk.

Word lengths of eight to 32 bits are supported, at sample rates up to a theoretical maximum of 10 MHz (96kHz for Peak LE). The file-format support extends to AIFF, Sound Designer II, WAV, QuickTime, Raw, System 7 Sound, Sonic AIFF, Paris, Jam Image Files, AU, MP2, MP3, MP4 (AAC) and FLAC, with a batch converter for processing or converting multiple files. As before, both VST and AU plug-ins are supported, and the two types can be used in combination within Vbox 3, the latest incarnation of the BIAS 4x4 plug-in routing matrix. A number of useful plug-ins are included even in the basic Peak LE, while Ambrosia Software's WireTap Pro allows for directly recording Internet or system audio. In a similar vein, Cycling 74's Soundflower enables the audio output of other audio programs to be recorded directly into Peak Pro, where they appear as virtual input sources.

The Vbox plug-in matrix supports VST and Audio Units effects and instruments, and now offers a variety of ways to cross-pollinate their outputs!The Vbox plug-in matrix supports VST and Audio Units effects and instruments, and now offers a variety of ways to cross-pollinate their outputs!Vbox has been able to play and record virtual instruments since Peak version 5, but now features a 'cross-synthesis effects' facility that allows one sound source to modulate another. You can use an audio file and a software instrument or two instruments as sources, and four different kinds of cross-synthesis are available: ring modulation, convolution, 'magnitude multiplication' (which is similar to convolution except that the output remains in phase with the input), and vocoding, for those classic 'talking synth' effects. The degree of modulation can be manipulated using a MIDI modulation wheel.

Although Peak doesn't yet offer real-time parameter automation, you can apply complex envelopes to plug-in parameters, which are rendered when you bounce the file down.Although Peak doesn't yet offer real-time parameter automation, you can apply complex envelopes to plug-in parameters, which are rendered when you bounce the file down.Another very neat addition is the ability to apply envelope control to processes that are often considered to be static, specifically pitch change and convolution. Peak also has the ability to extract the audio envelope of an existing piece of audio for later use. Plug-in envelopes can be applied while bouncing files, to control the depth of processing, making it possible to vary things like reverb depth from one point to another in an audio file. Furthermore, BIAS have given Peak the ability to do something that I've been nagging Apple to put into Logic Pro for several years now: it can bounce a track in place to make any applied effects and processes permanent. This works in real time and can include the effect of real‑time parameter changes, but I couldn't find any way to audition the effect of envelopes I'd created until I'd bounced the audio to a new file; it seems that full plug-in parameter automation in Peak is still a way off.

More evolutionary than revolutionary is the added choice of alternative pitch/time algorithms for optimising results with vocals or musical content, but it's still very important: with some material, transients must take priority, while elsewhere, smoothness is the most important quality.

Work, Rest & Playlist

Peak's playlist view has had a make-over in version 6, and now combines many of the benefits of the waveform view with the traditional playlist approach. Peak's playlist view has had a make-over in version 6, and now combines many of the benefits of the waveform view with the traditional playlist approach.

The playlist has been given a make‑over with more view options, while metering has also been upgraded, with user calibration now possible. Metadata supported in the current version includes read and write tags for the artist and album title and so forth, with PQ-sheet text export to include custom playlist reports with timings, index points and CD-TEXT. There are print or save to PDF options, as well as the ability to export as a tab-delimited file.

The appearence of the playlist editor is now quite like that of Apple's Waveburner, where the waveforms of regions added to the playlist take alternate positions on a pair of parallel timelines, with full access to the track markers. There's also an option to view tracks in linear mode, which is useful for overlapping tracks and lining them up visually using beats, for example. More editing functionality has been added to the playlist as well: you can trim, split and merge regions non-destructively, and adjust fades and volume envelopes using breakpoints on a graphical envelope curve. There are two edit modes, one of which preserves the relative timing of the regions (very useful for some types of track editing) and one of which allows free movement, as would normally be needed when compiling an album. Level envelopes can be applied across regions, not just to fades, and crossfade curves can be edited in great detail. Plug-in effects can be aplied to individual regions, and regions may be re‑ordered by dragging them to a new position in the playlist pane.

Suitable audio files can be added to a playlist simply by dragging, and playlists are created and saved as separate documents, so you can have several different playlists relating to the same audio material if required. As before, edits are non‑destructive, and your edited audio file it is saved as a new file, taking on the Peak file icon. If you keep the same name as the original, it will be overwritten with the edited version when you save.

Endless Loops

For sample editing, the looping tool set has gained Perpetual Looper, on top of Loop Surfer, Crossfade Loop, Loop Tuner and Guess Tempo. This newcomer appears to use a form of frequency-domain resynthesis (presumably taking a different approach from the existing phase vocoding option) to ensure glitch-free loops in typical monophonic sound sources, and is a very useful tool for creating smooth sample loops from material that refuses to play ball with a simple crossfade. Providing you use monophonic material that isn't too different in character at either side of the edit, the algorithm will smooth over the transition to stop the loop sounding 'lumpy'. You set the pitch range that best suits the audio you are working with, then use the Preview Button, adjusting the smoothing sliders to achieve the best result. When you're happy, hitting Apply processes the file. Controls include the means to separate partials from residuals: for example, you can separate the breath sound of a flute from the pitched tonal component.

There are several settings you can tweak to achieve the best subjective results; I found that processing non-monophonic material or using extreme settings occasionally produced interesting abstract sounds that bore little resemblance to the original, so there's clearly some creative potential here too. Loops may be loaded directly from Peak Pro into an SMIDI-compatible hardware sampler. Hardware sampler support has been in Peak for as long as I can remember and is still around in version 6, which is good news for those not already seduced by soft samplers.

Peak Of Perfection?

While Peak 6 should feel quite familiar to users of previous versions, the sheer flexibility of the program means that newcomers might miss out on many of its less obvious capabilities unless they do the unthinkable and read the manual, though basic editing is as intuitive as it ever was. There's really so much in Peak now that it would take a book to list everything it can do, but BIAS have to be commended on the way they allow you to use the program at pretty much any level and don't intimidate first-time users. The manual is also very thorough, with examples of key processes that you can work through step by step. Peak is really two programs in one: for the sound designer, it offers some very sophisticated looping and slicing tools, which, in conjunction with the new virtual instrument powers of Vbox 3, make it a real heavyweight for creating sample-library material. Perpetual Looper is a welcome addition in this department, and has plenty of potential for 'creative abuse' as well as for its intended purpose of looping monophonic material.

As a stereo editor, Peak takes over where your DAW leaves off, providing a remarkable range of editing and restoration tools, including the ability to remove clicks and glitches. What's more, that tool set gets better with every new version, and the additional plug-ins you receive with the Peak Pro XT 6 package let you get very serious about mastering. Peak's ability to handle batch processing takes the pain out of repetitive tasks, a degree of plug-in automation is now supported, and when you have your individual tracks tidied up, you can compile them into a playlist to burn your CD master or image file with all the necessary fades, crossfades, level envelopes, track markers and metadata. I really like how the playlist has developed over the past few versions, to the point where it now offers the best of both list and waveform views, with the ability to apply level envelopes to audio within the playlist and also to bring in plug-ins where necessary. The new high-resolution metering also offers a welcome degree of reassurance.

To sum up, then, Peak Pro 6 is a significant evolution of an already solid and firmly established stereo editing package. There's scope for further advancement in the areas of plug‑in automation and in the auditioning of some processes, but none of the new features detract from the familiar way of working, and they add considerably to Peak's sonic arsenal. If you previously thought of Peak as a Swiss Army knife, let's just say it has gained some useful extra blades, a better bottle opener and one of those things for getting stones out of horses' hooves!


Alternatives to Peak depend very much on your needs and on the computer platform you use. The closest Windows equivalent is probably still Steinberg's Wavelab, while DSP Quattro and Audiofile Engineering's Wave Editor for the Mac offer all the basics in a friendly format. I don't think anything rivals Peak's feature set, though.

Podcasting Features

Podcasting has become something of a big deal in recent times, so Peak 6 now allows users to publish their own podcasts directly to a .Mac or FTP server, with a user-definable bit depth and compression setting. All the necessary info is filled in on a single form to accompany the podcast.

To ease the creation of podcasts, there's also a new facility for Voiceover Ducking in the DSP menu, to automatically attenuate the music bed during a voice-over. This works by opening two audio files, the voice and the music bed; then you set the ducking attack, release and depth parameters to achieve the desired type and amount of ducking. Once set, the voice can be added to the ducked audio to create a new file. Another nod in that direction is the ability to drag and drop audio between iTunes and Peak playlists (you can also 'Send to iTunes' documents or playlists automatically without leaving Peak, choosing between using iTunes encoders, Peak's encoders, or sending uncompressed). This can streamline sending audio from Peak to your iPod.

Because much podcasting material is now gathered using portable Flash RAM-based recorders, Peak has also added support for unnamed markers in WAV files created by these devices when importing audio.

A Few Of My Favourite Things

As with any major software upgrade, Peak 6 features a host of smaller improvements alongside the headline features. One that I welcome is support for the Frontier Design Tranzport wireless remote controller, as I have one currently looking for a purpose in life!

Peak was one of the first pieces of software to include convolution as a process, but that has now been expanded to add automatic sample‑rate conversion for matching the impulses and target files in ImpulseVerb. Peak now includes DCAT (Dither Cloning Audio Technology), which purports to model the most popular forms of dither, though I have to admit that I've yet to hear any real difference between dither types on pop music at normal listening levels. Perhaps more important from a practical point of view is that Peak has always had really first-class sample-rate conversion, which BIAS call USRC (the U stands for Ultimate!); this is one area where significant quality loss can occur if you use sub-optimal algorithms. DDP 2.0 export is included as standard in Peak XT and is optional for Peak Pro, allowing you to send off masters in a robust image format supported by a number of duplication houses. For colleges and universities, there's Key Server support, which is well suited to educational lab environments wishing to use server-based authorisation. Yet another nice touch is that the inclusion of Jack OS X means you can use Peak's new real-time bounce to play out audio from Peak via external hardware and bounce it back to the same file, as you can now do with many DAWs.


  • Simply the most comprehensive stereo editor available for the Mac platform.
  • Can be used on many levels.
  • A wealth of creative tools, plus support for most of the popular file formats.
  • Well-written manual.


  • Though many improvements have been made to add envelope control, full plug-in automation would be welcome.


Peak 6 is evolutionary rather than revolutionary, but it does boast many very practical additions that will further endear it to both the mastering engineer and the sound designer.


Peak Pro 6 XT £879.99; Peak Pro 6 £429.99; Peak LE 6 £89.99. Prices include VAT.

Sonic8 +44 (0)8701 657456.

Peak Pro 6 XT $1199; Peak Pro 6 $599; Peak LE 6 $129.

BIAS +1 707 782 1866.