Processing Tango Audio Files is the first post in a series about tango music audio quality, how to appreciate it, and why it matters.
I’m writing this one because of a post by Clive Harrison in the Facebook group Tango DJ Forum about audio processing for digital tango music files.
Here’s his question. “I have been experimenting with processing some of my digital music files (particularly TangoTunes’ ‘Golden Ear’ releases) to reduce audible clicks or crackle. Do you apply any processing to such files (and if so, what tools do you use) or do you prefer to play them ‘as is’?”
You may ask why you, as a tango dancer, should care about such technical trivia, and I’m going to offer you a possible reason.
When we dance, we are inspired to move by the music (hopefully). Our ears convert the sound pressure variations in the air into signals which are sent to our brains to interpret. We convert this information into movement in real time because tango is an improvised dance, and therefore there is a limited time available to do this.
When dancing to live music played by musicians on acoustic instruments then the sound is produced by the instrument and comes directly to the ear. As long as we know the sounds of the instruments we can interpret them with no problem.
But with traditional tango, we dance to orchestras recorded decades ago, and mostly these days we will be listening to digital files reproduced over loudspeakers.
Unfortunately ‘digital’ does not necessarily mean perfect. The digital realm offers a wealth of possibilities for manipulation of the sound file, which is great, but there are more ways to get it wrong than right. When it’s wrong, the resulting distortion means our brains must work harder to interpret the original sound. This leaves less time for movement and increases stress.
You don’t have to understand a single technical term or be an audiophile critic for this to happen, you probably aren’t even consciously aware it is happening. But it’s an extra load for our already busy brains to deal with.
So next time you’re not having a great night at the milonga, maybe it’s not you. Maybe it’s just bad sound quality.
Here are some excerpts from La yumba by Osvaldo Pugliese with different amounts of treatment. This was the track under discussion in the original facebook post.
I bought this version from the Tangotunes tango music download site. The quality of the audio is nice. The surface noise and clicks are a bit annoying, but it’s not too hard to ignore them as they are fairly constant.
Here is the same track but processed to remove the clicks using Izotope RX5 Advanced. It took a bit of experimentation with the settings to get a result I was happy with, but now the clicks are gone and there is very little degradation of the music.
Now I’ve taken the declicked version and treated it to remove the noise. Pay attention to what’s happening to the room ambience and the pizzicato violin part. There is very little noise, but there is some slight degradation of the music.
This example is with with the software on an automatic setting. It’s too much. The music becomes harder sounding, and what happened to that lovely bass? The effect of the processing is heard on the longer notes. It’s like flanging, really unpleasant. There are files out there that sound like this though! Even with decent software (and RX5 is), ears and experience are still needed to get good results.
Reliquias issued this version on CD. It was produced quite a while ago without the sophisticated software tools available now. The high frequency content has been attenuated to reduce the noise. Unfortunately this also reduces the top end of the music. Too much bass boost has been added and the resulting sound is heavy and unappealing compared to the Tangotunes version.
The examples above show the variation of sound quality even though the file is in the digital domain, and hopefully it will help you to spot these problems.
It’s not uncommon to hear peak distortion, continuous overmodulation, bad equalisation, and even artificial reverb on digital tango files. These things weren’t there on the original recordings, they have been added later, either deliberately or by mistake.
In later posts I will explore what can go wrong with file formats, loudspeakers and room acoustics.
You can find the complete track for download at https://www.tangotunes.com.
Izotope restoration software is available via their website, the latest version is RX6. https://www.izotope.com/en/products/repair-and-edit.html
The music clips provided here are used under the ‘fair use’ provision of copyright law for educational purposes only.
Paul Strudwick is a professional sound engineer and member of the Institute of Professional Sound.
He worked for the BBC as an engineer before becoming self employed in 1996.
He has mixed around 750 live radio sessions for the BBC and mastered 1500 sessions for the BBC archive.
Currently he runs his own mobile sound recording vehicle and provides a variety of professional audio services, as well as organising and DJing at The Magic Roundabout Milongas.