Not so much a review as an overview and thoughts of a new piece of ripping software. 

What is AUI?

Audiophile Inventory’s AUI ConverteR is a Windows or Mac based tool for professionals as well as the home user. For use in Hifi its main features are – ripping discs for streaming and the conversion of file types for device specific requirements such as any high resolution home audio device, potable players and car head units etc.

The software offers:

– High quality sound conversion
– High precision (64-bit floating point) algorithms sample rates and bit-depth conversion (alphaC)
– Gentle dithering algorithms (alphaD) for  decreasing audio bit resolutions to 16 bit.
– Uses a solid and simple user friendly interface

The user is also able to add their own input and output audio formats (by using command line software – encoders, players, etc). The more professional features are not really something the average audiophile will be interested in and their specifics are beyond the scope of this review.

In short AUI is in my eyes a tool for ripping and converting files for the day to day home user, which offers a very high quality rip for a file based system, with features such as “Dithering” to retain the integrity and quality of a digital file allowing for (in experience) a smooth and transparent sound.

Applying Dither to conversions

When truncating an audio file (reducing its bit depth) from say 24bit to 16bit for example, maybe if the user wishes to burn a disc for a car CD player or another disc player elsewhere in the home we can run into “Truncating Errors”.

Truncating Errors are the result of this compression which manifest itself as missing bits, missing 1’s and 0’s in the digital signal leading to a loss in details, nuances and information within the audio track.

The effect of these truncating errors is what many refer to as a nasty digital sound or recording. Artifacts, hard edges and high frequency grainy noise becomes very apparent on down samples and compressed music. So, how can the signal integrity be retained and smoothed out? This is where “Dithering” comes into play.

Applying dither during the process of sampling from the 24bit original to the 16bit copy eradicates these loses and retains the information by adding a low level noise to the sine wave. Dither however is not a magic wand, it does add a background hiss to the music just like a tape recording of old, yet at levels far below. This level of hiss is only apparent on 16bit and above files when at very high volumes during extreme silence cues between passages.

The audio signal with dithering remains intact, retains details and does not have a hard digital edginess or apparent noise across the frequency range which has been left by the missing 1’s and 0’s. The sound is more transparent and smoother sounding.

AUI has a built in dither slider in the settings tab and fine tuning the levels of dither will produce better results dependant on the recording (whether it has already been dithered or not) any down sampling which needs to be undertaken or whether the user is ripping from a disc. The standard amount of dither which AUI provides is deemed by them as the ideal rate for ripping on the fly and in my experience using the software I have found that applying dither to a rip makes for a more musical and smoother rip, retaining or adding transparency and being a safe method to reach the optimum quality or the rip.

If a rip seems to have a level of background hiss which is not on the original disc then it’s advisable to re-rip that particular album again with dither turned off. I myself have not encountered this as of yet. The recording may already have some high dithering in place when originally mastered to physical copy. Remember, nearly all recording are originally mastered in the studio at either 24 or 32bit and are down sampled to 16bit for a standard CD .

A 24bit SACD would have less or no truncating of the original file (due to its original deriving from a 24bit master or 32bit) and therefore dithering is not essential. AUI has the ability to rip SACD’s to DSD 64 or 128 formats allowing for the playback of High Rez files on compatable DACs and PC/Mac direct systems also.

DSD is trademarked by Sony/Phillips, the actual file extension is .dsf (data stream file). AUI refers to DSD files within the software as DSF “1bit/2.8mhz” and “1bit/5.6mhz”. These numbers equate to:

1bit/44,1 kHz x 64 = 2,8 MHz (known as DSD64).
1bit/44,1 kHz x 128 = 5,6 MHz (known as DSD128).

The Software in Use

Using the AUI Interface is a breeze, the user is presented with a very simple GUI with options for sample rates, bit depths and file output type. The software covers all major file types, so if you wish to rip a disc to ALAC, FLAC,WAV,AIFF the option is there. Likewise if you wish convert pre-ripped files – say you originally ripped all of your files to Apple Lossless and have the need for them to now be in FLAC this is also an available option, or if you simply wish to make copies in other formats such as WAV for burning a CD for the car or MP3 for a portable music player.

Like other ripping software on the market AUI can obtain metadata by first opening iTunes. When the inserted disc ready for rip is recognised by iTunes and message appears asking if you wish to import the album simply click no. Leaving iTunes open however will allow for the album and track names to appear within AUI and be located into the albums folder once ripped.

Ripping is very straight forward. The trick is to create a Master directory on the chosen drive you wish to save all of your rips to. Within this folder simply add sub folders with a preference to how you wish the library to be displayed. Personally I create a folder with the artists name and sub folders for individual albums.

Then on the AUI GUI click “Open Files” navigate to the disc and select all files and open. Then clicking the three dots at the bottom of the AUI screen allows you to navigate to the destination folder, once selected click “Start” bearing in mind the chosen output file format, bit depth and sample rate required, as well as clicking on the “dither” button which will be required 99 times out of 100. A more specialised dithering can be obtained through a trial and error process using the slider in the advanced settings, but for standard usage of the optimised settings it’s just click click click and Start.

– Note: Some players/streamers will state that they will playback files of many variants, but in fact they can often convert these files to FLAC “on the fly”. You may wish to investigate this and copy and rip all your albums to FLAC for piece of mind so that there is no converting necessary and to maximise hard drive capacity. Personally I rip everything to the exact file it appears in on the disc, mostly WAV and on the odd occasion AIFF, for me I feel why change anything about the original recording, especially if the playback software will play these files directly as my Amarra 3.0 does.

My impressions of the ripped media files.

Bearing in mind as earlier stated I haven’t (yet) found the need to not use dither and have found that in practice multiple rips using AUI have sounded incredibly good and sometimes better than the original CD itself, offering a more analogue take on the sound with great midrange transparency and perceivable air in the top end. Now I’m not saying that these differences are game changing, but the subtleties which they convey are very pleasing to a high end system.

Details seem to portray a more solid leading edge and allow for a more natural decay of instruments, also revealing reverbs which are more understandable.

The difference is in these smaller notifications and cues which add more atmosphere to the performance.

Before AUI and being Mac based I would use X-ACT which is free software. X-ACT is extremely good software and gives an audio reproduction which is leaps and bounds ahead of iTunes, causing me to re-rip my entire library again after discovering it.

Now with AUI I find myself working back through my albums as and when I have the time. The distinctive difference is in all the smaller nuances, details and cues which add to and are crucial to the entire performance.

With many audio playback softwares available to the end user such as JRiver, Audirvana, Puremusic and Amarra, it makes absolute sense that a good aolid ripper is essential too. Once you have experienced the differences with specifically and professionally designed playback softwares, it makes sense to put your trust into a ripper of the same calibre and Audiphile Inventory’s AUI ConverteR 48×44 is one to consider. A Free Trial as with any good vendor is available feom the Audiophile Inventory website.

Price – Varies from $33 – $249 dependent on edition.

Dan Worth