I think the writing of Rafael Valdivia is right. Actually, on this subject we could debate for hours. In my opinion, it all started in the era of poor sound systems of the 80s, precisely with the rise of salsa.
The bustling crowds that attended the concerts demanded a sound volume that the few amplifiers and archaic electroacoustic systems of the groups and companies of the moment were unable to guarantee. The solution that the soundmen found was the supersaturation of the power stages. This resulted in not only an overcompressed mixture of high levels of distortion, but also the frequent breakage of the loudspeakers due to the excess of square-profile sound waves present in the signal.
At the end of the 90s, the first moderately efficient sound systems entered, capable of sounding audiences of a few thousand spectators. However, the irreversible damge was done: the concept of dynamics in music had been lost.
Let's look at it from a slightly more technical perspective. The nominal power developed by an electroacoustic system must cover the dynamic range of the processed sound program, leaving a reserve (headroom) for possible peaks. When we had little, there was nowhere to get for the reservation. The power was sufficient to cover just the necessary dynamic range and develop an adequate sound pressure level in a given enclosure. At present, with greater technological facilities, the right thing is to have the necessary power to guarantee the ideal sound pressure level at any point in the room for a certain genre of music (for example, 90 dB RMS), plus a certain reserve such as headroom (say 14 dB). This would correspond to the use of x number of speakers per channel, of a certain model and brand, of a certain efficiency.
A previous calculation and design of the system and its distribution is an indispensable factor, although this important step is often omitted. An engineer with skill and good spirit uses the available power in the manner described. With greater or lesser taste, it achieves the right tonal and musical balance. An inexperienced «console driver», victim of the crisis of the 80s (or a disciple of one), whose empirical knowledge does not allow him to do anything else, simply uses the 104 dB mentioned in full, reaching an exaggerated sound volume, close to Painful threshold, to the detriment of the dynamics and therefore of the quality of the music being amplified.
Another relevant factor in the tonal balance is the balance between the different sound spectrum registers. The lower frequencies have the greatest masking effect. Our music is full of them. A bass drum, bass or tumbler featured in excess in a mix, offer a strong masking action on other elements, including vocals, threatening the intelligibility of texts.
As Rafael well explains in his writing, the performers themselves are sometimes not cooperative with the work of the engineer FOH (Front of the House) in charge of the room mix, demanding excessive levels of sound intensity on their monitors. Again the serious sounds are to blame. The higher the frequency, the more directional it is and vice versa. The stage monitor, aimed at the musician, emits signals in a relatively uniform frequency range to the front. However, low frequencies, less directional, reach the room, soiling the overall sound that the audience perceives. The higher the volume on the stage, the more murky the sound becomes in the room.
There are two concepts when working live: amplification and sound reinforcement. The latter, more dynamic and less aggressive, takes advantage of what, for better or worse, comes directly from the stage, adding only what is missing; whether they are global sounds from certain sources or part of them; for example, the acute components of the piano signal, whose bass already arrives from the stage.
Unfortunately, this is not the method commonly used in our country. The amplification of 100% of the signals emitted by the sources is preferred, until obtaining a balance whose lower threshold is the direct sound of the stage, so that it is masked by the room mix.
Fundamental role in the sound mix play orchestration and musical direction. A well-balanced arrangement and interpretation with the appropriate dynamics, undoubtedly requires less volume on the monitors than an unbalanced set.
The old school left us as a legacy recorded phonograms with just two or three microphones, where absolutely everything is heard. The first person responsible for the mix was the arranger, followed by the interpreter. The engineer didn't have many tools, but he didn't have much to correct either. The dynamics were built naturally and not based on multiple processing and constant changes in the parameters of the mixing console. There are few current ensembles that sound well balanced internally without the use of technology, sometimes excessively.
I had the opportunity to work for many years with a big band, which interpreted arrangements mostly conceived by a great musician of the old guard (from the aforementioned time of the three microphones), José de la Caridad Picayo, and conducted by the great teacher Demetrio Muñiz The sound pressure level in the tests, where it was only necessary to amplify the voices, did not exceed 87 dB. When the orchestra left the stage the work was very easy; Even with multiple monitors, the musicians themselves balanced their performance until they heard each other. The orchestra behaved like a large multi-band compressor, and it only remained to beautify what already sounded good.
On many occasions, in the rooms where the band was presented during its international tours, maximum permissible limits of sound pressure level were established, sometimes below 100 dB. I don't remember any occasion when the needle of the sound level meter that they put in front of my eyes as constancy, reached that measure. It was a perfect symbiosis between orchestrator, conductor, performers and engineer.
We can only appeal to the conscience and good taste of arrangers, performers and engineers, and urge, now that we have more access to the Internet, to find out how they are working in the world, draw conclusions and apply them to our musical field.