In the figure above: on the left, a reference scale of a high quality preamplifier, with clipping level at +26db above the reference 0db; on the right, a representative diagram of the average performance of three quality levels of preamplifier: as the quality decreases, the useful dynamic range is reduced, due to lowering of the distortion threshold and raising of the noise threshold. Furthermore, low-quality preamps often offer slow transients and low-quality harmonic saturation when used at high gain levels.

Registration levels

With regard to voice recording levels, the discriminating factor lies above all in the ability of the preamplifier to optimise audio quality in the area of harmonic saturation:

• for classical and operatic vocals and in all cases where perfect clarity and fidelity is required, the best results are generally obtained with an excellent transparent preamplifier, keeping the highest peaks below the clipping point, with a margin of at least 6 db
• if you were obliged to record a vocal source of the kind mentioned above with a coloured preampli, it would generally be a good idea to move further away from the clipping point, e.g. by 12 db or even more;

NOTE

In reality, this will depend on the characteristics of the preamplifier: there are those that colour the sound at any level of use and those that remain neutral up to a few db from the clipping point, the above indication is only a guideline

• for vocals in pop, rock, funky and dance, generally the best results are obtained with an excellent coloured preamplifier, taking care to push the gain more or less into the real saturation range (which will vary from one preamplifier to another) according to the specific sound requirements, thus seeking a balance between

1. grit and saturation, on the one hand
2. softness and clarity, on the other hand