Euphonia3 from TBProAudio
Euphonia3 is the latest version of TBProAudio’s compact audio spectrum balancing plug-in that was last reviewed on this site over ten years ago. That was version 1.0 – version 1.5 added a custom reference mode to enable users to tailor tonal balancing for genres other than the included styles, and version 2 added improved spectrum matching, a mix control, gain matching function, switchable minimum phase/linear phase filters and a GUI redesign. Version 3 adds free GUI scaling, updated Mac universal binaries, and completely rewritten DSP code.





What Can it Do?
Euphonia3 (Euphonia going forward) is a user-friendly spectrum matching plug-in that has several modes of operation. As you can see above there are four general musical genres built in, Pop, Dance, Jazz and EDM. There is also the Custom genre where you can add you own style based on analysing a file of that genre, which it turns out is a very useful function. While I was surprised that Rock in not a built in style, Rock is arguably a type of Jazz, but often falls into Pop and EDM styles (TBProAudio actually used Rock samples to tune their Pop category). Although the Euphonia user manual states “Please use the style which fits to your audio material!” genres cross borders all the time, and you may find you actually like Pop rather than Jazz for a given Jazz song. As Joe said, “If it sounds good, it is good.”

Euphonia Controls
I have several spectrum matching plug-ins that all work reasonably well, but Euphonia is faster and easier to operate than most with a unique fast analysis mode I'll describe below in "Part 2". It also has less extra bells and whistles, such as additional EQ that can be impressed on the spectrally matched EQ correction (a function which seems to somewhat defeat the purpose of a spectral match!). It also lacks dynamics control and saturation functions, but since Euphonia is intended to help balance a final mix, you probably have already applied compression and distortion during the mix process. And if not, such as mastering a final mix, you can always apply such audio processing after adjusting the spectral balance, using full-featured dynamics and saturation devices.

In the view below you see an animation of the three buttons in the left centre area labelled only with graphical notation (previous versions named these, from left to right, Capture, Stop, and Process). They are in fact the capture, stop/bypass, and process controls. In the middle is a large Tuning knob that switches the genre from Pop to Dance to Jazz to EDM to Custom – these are discrete settings in that there is no blend between any two of them. At the right centre area are the Mix and Gain controls. Mix adjusts the strength of the added EQ and Gain is an output level control but it can interact with the Match button below it in odd ways. More about that later. Along the bottom are four controls to save and load “fingerprints” (left corner) and reference files (central area) which provide various ways to analyse and adjust your musical files. There is one more control, marked A/D, which indicates if the filter creating the EQ correction curve is analogue or digital (button light on) – analogue is minimum phase like a real hardware EQ and digital is linear phase that can only be accomplished in a software emulation and requires latency – a rather high 16,383 samples in Euphonia at any sample rate which is 342 msec of delay at 48 kHz. However, since Euphonia is not in any way intended for tracking use, such a delay should be taken care of in a DAW.



How to Work It – Part 1
In use you should place Euphonia as the first plug-in in your mastering chain (you may want to follow it with compressors, limiters, saturation, etc.). If you are using it in a mixing project, place it at the top of your master bus. Press the middle Stop button (icon is a square stop symbol), start the audio playback and click the left Capture button (a square target symbol). Let the audio material run completely through to the end in the "capture" state. You can run the analysis in "real-time" as the DAW plays or you can use your DAW’s offline rendering function which will speed things up considerably depending on how many other processors you have active. When the playback or rendering is finished switch to the "idle" state using the Stop button which will stop the capture mode and save an audio “fingerprint” in Euphonia. If you save your DAW project at this point, the fingerprint will also be saved within Euphonia.

Note that the user manual states, “As soon the LED above the “capture” button lights green Euphonia has enough data.”, but also states, “At first let the audio material completely run through Euphonia with "capture" state enabled.” This second statement should be your guide – the green LED lights up in a split-second after the capture mode is started, and that rarely has full spectral information from my testing. Also note that you can remove the current audio-fingerprint by switching from either the Process state or Stop state back to the "Capture" state.

To hear the results of spectral matching of your audio source to a specific genre, click the right "Process" button (icon is a “double” EQ curve) and start playing the audio material again. Set the Tuning to the genre you want, and adjust the Mix level. Note that Mix level often needs be only 20% to maybe 40% for useful improvement – sometimes 50% or more may be needed, but may result in over-processed sound.

How to Work It – Part 2
There is another way to create a fingerprint for an audio source file that processes the entire source file very quickly – using the FP (FingerPrint) Load button in the lower left of the GUI. Even if you have the same file already loaded in your mixing or mastering project, you can use FP Load to quickly create a fingerprint of the file without needing to use the Capture mode. Using this method you are ready to run the Process mode in about a second. This feature is unique to Euphonia3 in my experience with other spectral matching tools. Note that you can save any fingerprint (created either by playing a file or using the Load FP method) to a file, and when you save a project in your DAW, the current fingerprint will be saved automatically, so this is an alternate method that allows you to you have the fingerprint immediately available if you need to process the same source audio in a different project or different DAW, and is also useful if you wish to quickly load a previous audio fingerprint file in order to convert it into a ref file, as described below.

How to Work It – Part 3 – There is More!
In addition to the four built-in genres there is the Custom selection that requires a user-supplied genre reference. To use this mode you simply choose a previously created reference (ref) file with the genre you want, or choose an audio file of music you want to turn into a genre reference, and load it using the REF Load button in the lower middle area. This will quickly install a previous reference file or provide a temporary reference created from your loaded audio file. You can then play your source material using the Custom selection and it will be processed to spectrally match your custom input – and you can still switch to Jazz, Pop or other built-in genre to compare results, but only the Custom setting will use your reference genre.

Note that converting an audio file to a reference does not save the temporary reference file automatically to the Euphonia folder. To save your own custom ref file you must first load your desired reference audio file as a Fingerprint using the FP (FingerPrint) Load button described earlier, then click the REF Save button which enables you to name the new ref file. This is very handy if you want to use your custom reference again and don't want to keep the original audio files on your system – it saves a lot of storage space in the process. In one of my tests I used 196 MB of audio files to create a custom ref file, and the ref file itself is less than 2 kilobytes!

And Another Thing
The Gain control and Match button must be mentioned. Match is not really an A/B (input/output) matching system like TBProAudio’s ABLM2 or ABLM Lite provided in some of its other plug-ins. Match is described in the user manual as “The “Match” button matches the gain value to 0.0 dBFS maximum peak value.” and “Euphonia clips the signal at 0 dBFS in the “process” state to avoid signal overload.” However, I find this a questionable function since I’ve used gain-staging in mixes for decades and would never let peak (true peak actually) exceed -6 dBFS or lower. I usually aim for -12 dBFS. So I quickly learned never to click the Match button. You can click the dBFS digital readout itself (to the right of the Match button) to reset the peak reading without Euphonia trying to boost the signal to 0 dBFS peak, but as you run the source file (in real-time or using DAW rendering) the dBFS reading will continuously update to the maximum instantaneous sample peak. The Gain control can then be used to adjust the peak up or down as needed to provide reasonable headroom.

Euphonia does tend to match the loudness between the Stop (bypass) mode and Process mode, but while sometimes it was within a few tenths of a dB, other times it was off by two or three dB. For my testing, as I always do when evaluating the effects of EQ, dynamics and saturation, I used ABLM2 to instantly match before/after levels to within a tenth of a dB (or LUFS). I’d love to see some form of TBProAudio’s ABLM integrated into Euphonia.

What Does It Do?
Below are spectral plots of the four genes built into Euphonia – these all follow the generally found roll-off of high frequencies reported in many studies of music, but each shows slightly different slopes and different emphasis.



Euphonia does not try to force the spectral response of input material to match these smooth average curves, but “tilts” input spectra to generally follow the genre curve which can result in better balance of the overall tonality, as you can see in the plot below. This plot shows one bar of a jazz tune before and after applying the Jazz spectral curve – this is an un-smoothed spectrum where you can see prominent individual notes and harmonics. The original sound was a bit “thin” sounding and the corrected sound is well balanced.



But the built-in genres don’t work for all musical styles. Some styles, like solo piano, do not show improvement using any of the included Euphonia genres, and in fact can be degraded using a general genre like jazz or pop. In such a case a custom reference is needed. With a piano solo I had recorded none of the built-in genres helped at all – results were boosted strongly in the high frequency range. I found an excellent solo piano performance by David Lanz in my mix reference folder, and used the REF Load function to set the custom genre to David’s performance (spectrum shown below).



The results were excellent when I used this with my piano recording. You can see how different a solo piano spectral distribution is from the four built-in full band genres. The piano spectra tends to be relatively “flat” (+/- 3 dB) from about 90 Hz to 900 Hz instead of rolling off pretty much continuously from 100 Hz up. And above 1 kHz the piano spectra drops about 50 dB at 10 kHz, while the main genres drop only 15 to 25 dB over the same range. This is why my piano solo sounded so “tinny” using any of the built-in genres. Great to have the Custom Ref mode.

How Does It Sound?
Spectral matching is controversial in some circles since one may argue that trying to force an overall spectral distribution on a given audio recording is not necessarily a valid approach. I have found spectral matching to often provide increased clarity and sometimes increased loudness perception (even with “official” EBU R128 loudness matched). I have included an audio file with four examples that each start with the original audio and about halfway through I switch in Euphonia – and in all four cases the loudness is matched (to within 0.1 dB) using EBU R128. You’ll probably notice the Euphonia processing usually sounds a bit louder, even though, technically it is not.

One area where spectral matching provides little or no improvement, even if you have an appropriate genre to apply, is when the source material is already “perfect”. I find tracks from some commercial albums by Sting, Norah Jones, and Dire Straits, for a few examples, are changed almost imperceptibly using the POP genre, even when the Mix level is pushed way up. And if you analyse the correction provided, you quickly see why – the added EQ is nearly “flat”. In other words, such productions already match the Pop genre very closely! If all your own musical productions are already “perfectly” balanced, you may not need Euphonia, but if sometimes they seem a little “off”, you could find it very helpful.

One question to ask of any audio processing, especially when used for critical mastering, is does it create any unwanted distortion, noise/aliasing? Euphonia3 does not create any distortion or other noises that I can measure down to the limit of my testing (-145 dBFS). So Euphonia3 provides very clean EQ adjustments.

Technical
Requires Windows 7, or later, OpenGL 2 GFX card/Mac OS X 10.11 or later, Metal GFX card. Plugins provided for Windows: 32/64 Bit VST, 32/64 Bit VST3, 32/64 Bit AAX. Formats for OS X: 64 Bit VST, 64 Bit VST3, 64 Bit AU, 64 Bit AAX.

I tested Euphonia3 using a PC Audio Labs Rok Box with Intel Core i7-4770K CPU @ 3.5 GHz, 16 MB RAM running 64 bit Windows. CPU load was pretty much constant at 0.4% running at 48 kHz in REAPER. Latency is zero unless the linear phase mode was used, in which case it is a constant 16,383 samples which is a lot, but not an issue for its intended use in mixing and mastering.

Pros
A very effective and easy to use spectral matching tool with several methods of analysing an input file and using either one of the built-in genres or setting up a custom genre.

The unique Load FP (FingerPrint) control enables creating a fingerprint in seconds rather than needing to play the source file.

The Load Reference function enables loading either a previous Custom ref file or loading an audio file which it automatically detects and processes into a ref file.

DAW automation support of all controls other than Analogue/Digital EQ processing which is not something you want to change on-the-fly due to significant latency change.

Low CPU load and no latency unless the Digital EQ processing is used which adds a significant 16,383 sample latency, but latency should not be an issue for its intended applications.

A reasonable price for such a time-saving tool.

Cons
Nothing really important – a recommendation for a future version would be to add TBProAudio’s ABLM loudness matching function. And a few more built-in genres would be helpful, but you can easily devise your own using any excellent commercial releases. I’ve already created and stored half a dozen custom genres.

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