Tango DJ resources
Experienced strange sound? Take a LOOK at your music!
Sometimes if your ears tell you that there is something wrong with the music you might have to take a look at your music!
Overmodulating
While DJ-ing a Milonga suddenly some tracks of one tanda sounded terrible. It was a tanda of Horacio Salgán with newer recordings which should have good sound quality. (ok, some people might say: this is what you get playing a tanda of Salgán..) The effects were similar to a distored signal. I managed to get rid of it by changing from professional +4db signal to consumer -10db signal and adjust gaining on the mixer. But actually there should not have been any problem in the first place. So I took a closer look at these Salgán tracks.
One of these tracks was "9 de Julio" which I use as demonstration. The following wave is taken from the CD Silbando - Horacio Salgán 1953/57 (EU-13006) published by the label Archivo TK in the year 2009 in cooperation with the BATC. Everything is ok with that one, this is how it should look like. Highest peak is just reaching the maximum level and since it is a mono recording left and right channel are identical.
Now what is going on with the track I used at the milonga? The following wave is "9 de Julio" also from a BATC CD Horacio Salgán 1950-1956 - BATC (orq 257).
Two things are obvious here.1. the right channel is way louder than the left one and 2. both are way too loud and therefore exceeding the maximum level and cutting of part of the music information. But I did not experience these artefacts on my home stereo system where I use my echo audiofire with a -10db consumer level connected via SPDIF. Compared to the track above it sounded louder and with more dynamic why I used this version for the Milonga. This is also the reason why major labels started to use compressors to push up the signals on their CDs to make them sound louder and therefore better to most people. It is necessary to listen closely and not getting fooled by just the sound volume.
But then I was wondering why this is being found on a BATC CD. Because normally BATC releases are rather natural sounding and unfiltered. So I took a look at a label where I'd have expected something like this. This wave is again "9 de Julio" from the CD Grandes del Tango 32 - Horacio Salgán CD 1 published by Lantower:
Yes, it is the same picture, because it was the same wave! All the tracks on the CD Grandes del Tango 32 - Horacio Salgán CD 1 published by Lantower are identical with the tracks on the BATC CD Horacio Salgán 1950-1956 - BATC (orq 257)! All of them being too loud and being able to produce overmodulating artefacts during playback.
So the second thing I found out while researching this issue was that obviously one label copied from the other AND not even bothered to take a brief look at the obviously wrong modulated tracks before publishing!
Stereo sound on an old tango recording?
While listening to many tangos you will come across some tracks having something like a weird stereo sound. Which is quite strange since the first commercial stereo two-channel records were produced 1957. So obviously all the golden age tangos were recorded in mono. So one would expect the left and right channel to be the same. This is the case in the following wave of "En la buena en la mala" played by Orquestra Enrique Rodríguez from the CD "La Fiesta Del 40 vol. 18 - Tangos / Almagro Vol 18" (DJ compilation) or "Enrique Rodríguez Y Su Orquesta Típica 1939-1946" (EBCD 101) published by El bandoneón.
But most likely you will also hear a tango having some kind of weird stereo sound. Sometimes it does not bother or even sound good, sometimes it can be disturbing. The next wave is again "En la buena en la mala" being played by Orquesta Enrique Rodríguez taken from the CD "Tangos Con Armando Moreno" published by Reliquias (EMI / DBN) or "Esto es puro compás" - BATC 89061 published by BATC. I took a closer look at that one, because the sound of this version was quite disturbing. It sounds like the music is jumping from one speaker to the other all the time.
You may click on the graphic in order to get a larger view. Take a close look at the wave and compare left and right channel at the marked sequences. You will notice that there are clear differences.
I personally don't like this kind of sound manipulation. Especially when the processed sound is rather disturbing. If the original recording was mono it should be treated like that. In addition if you merge these two tracks into one mono signal like it is done on some professional PA-systems by default it would sound even worse. And I wonder how this "jumping sound" would sound being played on a large venue on a PA-system with a stereo setup.
Out of phase
I am not a sound engineer and therefore I do not know the correct vocabulary for these matters, but I do hear if something is somehow wrong. Therefore another strange sound brought me to this WAVE:
It was brought to me that this can be described as out of phase. It is definitely not supposed to be found on a CD. In order to rescue this track in case you have not got another version you might consider to choose one of the tracks and copy it.
BATC ORQ-241 / AMP CD-1189
Some BATC CDs have the same tracklistings as AMP or CTA CDs. Does that mean that you get the same thing? You may find something like this:
WAVE of track 10 (Mosquetero de arrabal) from AMP CD-1189:
WAVE of track 10 (Mosquetero de arrabal) from BATC ORQ-241:
