I was at a milonga a while ago in the East Midlands where the DJ was prelistening with open ear bud type phones while the current music playing was so loud that at least one dancer left the salon altogether, rather than risk damage to his hearing. When I left, myself (well before the end) the music could still be heard two streets away.
More recently, in the South West, I overheard a dancer asking the DJ to turn the music down a little. The answer astonished me: “Oh sure, sorry, I couldn’t hear how loud it was, I don’t have my hearing aids in”.
I have taken to using a sound level meter when I DJ, and find volumes that peak at around 85dB to be fine. There are plenty of mejays that play ‘bang bang bang’ music (regardless of sound level), and they are not usually short of fans who seem to equate ‘loud’ with good. More discerning dancers, perhaps go elsewhere.
Peak volumes at 85dB (90dB max) are fine for me, but beyond that, the sound can be fatiguing (particularly if the sound system and room acoustics are not good) and, of course, sustained high volumes can lead to permanent hearing loss. I wonder how many DJs (not necessarily restricted to tango, of course) have done a huge amount of damage to their own hearing and may be quite unaware of the subjective effect their chosen replay levels are having on others.
I’d say that if you are sitting and chatting at a milonga, you shouldn’t have to raise your voice to be easily heard by the person next to you. If a well-attended event has dozens of people having to shout over the music, and the DJ turns up the volume to compensate, then I’m heading home quite early.
In some venues it can be quite a challenge to get acceptable volumes in the centre of the dance floor, without excessive volumes close to the speakers. Having them positioned quite high, so that they are above anyone’s head, can help a bit. But two speakers at the narrow end of a rectangular space can easily lead to big differences in SPL from one end of the space to the other.
I measure SPL when setting up (while the salon is still empty), and check it again as the room fills up – as people absorb sound. There are several free apps for smartphones that do a decent job of measuring SPLs. At the least, every DJ should do some simple listening tests to establish what an objectively measured safe volume sounds like to THEM, before they start relying on their own perception of loudness.
Another aspect of volume is the management of relative volume between songs. Most DJ software can scan music files and determine peak volumes and an average volume. I use media player Foobar2000 and it incorporates a well-known utility called ReplayGain for this purpose. My whole working library has been scanned by ReplayGain, and values have been set, song by song, to even out the differences in mastering volume of the music files. The algorithm isn’t perfect, but I rarely find I need to touch the master volume control when I’m playing a set – it generally does a very good job.
It’s annoying to have paid good money to attend an event and to find one song too quiet and the next one blasting your ears off. I’ve heard both experienced and novice DJs get this wrong too often. Last year I attended an event where the guest DJ was playing Troilo (and dancing). The 2nd song in the tanda was so much louder than the first that he just about dropped his partner and rushed over to the mixer to adjust. It shouldn’t have been necessary and it wouldn’t happen to me.