‘Bits are bits’ was once the war cry of hard-line audio objectivists who maintained that digital was incorruptible and should always sound the same. After all, bits are just bits, and so long as the bits are the same, so will be the sound of the music they convey. See all software reviews.
Audirvana Plus is a software music player that certainly helps to disprove any idea that all digital music players sound the same. It’s a high-end software audio player for OS X, able to play every high-resolution format you might ask of it. See all audio and music software reviews.
For anyone unconvinced of the differences between players, try the two most popular media players, iTunes and VLC. Neither is clearly better – but they are quite different. Step up to audio-tuned players like Amarra, Bit Perfect, Decibel and Audirvana Plus, and you’ll get an idea of what’s really possible. Visit our Chord Electronics QuteHD review too.
Audirvana Plus can work as a standalone Mac application, complete with its own inimitable player interface; or serve as a background application that powers iTunes behind the scenes, leaving you with just the regular iTunes app and its familiar layout. If you take the iTunes route, there are also a couple of less-obvious features that can prove invaluable. Take a look at Free Audio Editor 2012 review.
The look of the Audirvana Plus app is skeuomorphic in the extreme – in this case, trying to take on the look of a 1980s black hi-fi amplifier. Or with the inclusion of a big central information display that shows album artwork in its front window, it could even be said to resemble an AV receiver.
You load music into a playlist, either by dragging tracks or folders full of tracks into its Dock icon. Or press the Playlist button by the amplifier’s left foot to bring out the separate playlist window. Look out for a smaller button on the amp labelled Display Off. It doesn’t dim the display but actually hides the app, as if you’d pressed Cmd-H. Pressing the Power button quits the app.
A large knob graphic to the right serves as volume control, available if your external digital-to-analogue convertor (DAC) supports adjustable gain. And even if it doesn’t, there is software adjustment of volume available on demand.
Within the app’s Preferences you can choose whether to engage any digital volume control, and if so you can play with advanced dither features, for those times when convenience calls and you need to use a resolution-reducing digital volume control.
As well as displaying embedded cover art (or folder.jpg/cover.jpg images from the album folder), the main display gives rich track information from each file type.
Just above the linear timeline bar is a read-out of the file’s type and sample frequency; the opposite end shows what’s actually being outputted to the DAC, indicating if the app or the Mac’s Core Audio settings have recoded the audio stream.
Audirvana Plus can upsample audio, such as 16-bit/44.1kHz CD to 24-bit/96kHz, a strategy that can be heard to confer some of the better sound quality of actual higher sample frequency audio.
From Preferences, you can set the system to automatically upsample, either by the sonically preferred factors of two – such as 44.1kHz to 176.4kHz – or to the DAC’s maximum.
Sample-rate conversion is handled by default by the well-regarded iZotope 64-bit SRC plugin algorithm, with plenty of fine-tuning available for the filter characteristics.
Also from the filters tab is an option to globally invert signal polarity. Getting the ‘right’ overall phase can have a subtle but useful benefit on the final sound.
A toggle button on the front panel to accompany the +/- inversion graphic would have been useful though, rather than having to delve into Preferences each time to experiment.
Direct Stream Digital
As well as the usual compressed formats of MP3 and AAC, and lossless audio like FLAC and Apple Lossless (ALAC), Audirvana Plus is one of very few software players that understands Direct Stream Digital (DSD). This is the 1-bit high-resolution format taken by SACD, Sony’s planned replacement for the Compact Disc at the turn of the last century.
The SACD format, along with its erstwhile rival DVD-Audio failed to gain mass-market traction, but there remains a strong underground audiophile following for hi-res audio. And that now includes DSD music, whose natural sound can again be enjoyed now that it can be extracted from SACD discs and also bought commercially as raw .dff and .dsf files.
If you have a DSD-capable DAC – over 40 models have launched in the last two years – you’ll get to hear the potentially jaw-dropping walk-through sound of this quixotic 1-bit audio format being played natively.
And even without a DSD DAC, you can set Audirvana Plus to convert DSD on the fly into all manner of PCM for any regular DAC to play.
By setting Audirvana Plus into iTunes Integrated Mode, it’s also possible to convert and save DSD files as lossy or lossless PCM files of varying sample rates.
After selecting iTunes Integrated Mode from the app’s application menu, click on ‘Add files to iTunes...’. This creates proxy files for iTunes to play. This key feature enables your DSD to be heard on devices like iPhone and iPad, although it will then inherit some of the shiny signature of PCM audio.
Remember, though, that for use on an iPhone you’ll need to restrict sample frequency to just 44.1kHz since the Apple phone is not smart enough to play audio beyond 48kHz sample frequency.
Sound quality from Audirvana Plus is a noticeable step above iTunes. It is able to show increased clarity, with better perceived stereo precision, for example, meaning less ambiguity about the positioning of instruments and voices in the mix.
Focus can be tightened further in some cases by selecting additional options in the Audio System tab of Preferences.
‘Exclusive access mode’ is Audirvana’s label for hog mode, where the music playback software takes exclusive control of the audio bus. This can also prevent system alerts and other effects from being unexpectedly mixed into the stream sent to your hi-fi systems.
The ‘Direct mode’ option from the same tab, combined with Integer mode where available, will reduce Core Audio stages from the signal path for better sound. This neatly replaces some core functionality that was removed by Apple with the move from 10.6 (Snow Leopard) to 10.7 (Lion).
Integer mode is a useful way to maintain a bit-perfect signal path, avoiding the internal conversion to floating-point register and optimising synchronous CPU load at the driver level.
With such options engaged, you can expect to hear a slightly sweeter top end; more like real musicians in the room and less like a playing CD.
We compared Audirvana Plus to our preferred BitPerfect and Decibel players, using PCM tracks like 16- and 24-bit FLAC, WAV and ALAC. Here we found Audirvana to have even kinder treble and effortless extension along with a better sense of colour and vigour to the music.
Turning to DSD music, we lined up a Chord QuteHD, Benchmark DAC 2 HGC and TEAC UD-501 – all three DACs able to natively decode DSD64 audio.
And here the combination of Audirvana Plus running on Mac mini showed clearly better sound to even the best 24/96 and 24/192 material we could find.
Transients were replayed as if there were no recording medium, while stray room reverberations from the recording session were captured and returned naturally.
Playing DSD over USB using the fledgling DoP 1.0 standard using Audirvana Plus is getting closer to delivering on the promises of perfect sound that was advertised at CD’s birth in 1983.