In this article we address five common audio myths. What are they and why don’t they stand up to closer examination?

Myth 1 - A Compressor Makes Things Louder

Compression reduces gain - it makes things quieter. Make-up gain can compensate for this and restore the lost level caused by gain reduction introduced by the compressor, and if taken further can make things louder that they were pre-compression. Particularly as, with the dynamic range reduction, make-up gain can be used to cause an increase in average level compared to the uncompressed version. But it isn’t the compression effect which does that. It’s the contribution of the make up gain, which is after all just a volume control conveniently placed after the compressor section.

It’s not helpful to use compressors with settings which increase the apparent level as they make A/B comparisons between compressed and uncompressed versions difficult to assess. The louder version will usually sound ‘better’ although it’s actually just louder. If you want it to be louder, use the fader.

Myth 2 - A Cardioid Mic Is Only Sensitive From One Direction

A cardioid mic is insensitive from one direction but is sensitive over a wide angle, for example it is only 6dB down at 90 degrees off axis. The behaviour is sometimes presented as being similar to a torch or flashlight, with the mic ‘hearing’ the thing directly in front of it like a torch shines on what is in front of it. That just isn’t what happens. If this were the true behaviour of a cardioid mic, if you were to move off axis the audio would inaudible with only a small movement and more importantly the sound would remain consistent while disappearing. If you try this with a typical cardioid mic you’ll find that the attenuation is modest until you get right round to the rear, and the sound is far from consistent while doing it. This can be a useful way to EQ sounds at source by working further from or closer to ‘on axis’, but describing the behaviour of a cardioid mic as being only sensitive to sounds coming from in front isn’t accurate.

Myth 3 - Digital Creates An Inferior Sounding Stair Step Waveform From Its Samples

We shouldn’t be surprised that this myth persists, we’ve all seen the staircase of samples diagram for so long now. Digital sampling actually creates a series of data points, the gaps between which have a duration but the points themselves effectively have no duration. When these samples are reconstructed into a waveform by a D/A converter a smooth waveform is produced.

This is because representing the data sampled by an A/D converter as a stair step waveform presents the samples as a continuous time function in which the waveform has a defined value at every point in time. A sampled signal isn’t like this. It is a discrete time function - It’s only got a value at each instantaneous sample point and in between these sample points, rather than remaining at the previous sample’s value, the value is undefined. The analogue counterpart of this discrete time signal is a waveform which passes smoothly through all these points. A stair step graph misrepresents the data and the waveform - i.e it is wrong.

Myth 4 - Room Correction Software Can Correct The Influence Of Your Room’s Acoustics On Your Monitoring System

This type of software would be better described as ‘speaker calibration software’ as it measures the combined effect of your monitors and your room at the listening position and calibrates the frequency response, and often the phase response, of your monitors to minimise the influence of the room by calibrating the monitors’ output to compensate for it as best it can.

These products are very effective. However there are limitations to what this approach can fix. For example this approach can’t address cancellations caused by room modes or room resonances causing long reverberation at particular frequencies. It can’t ‘correct’ the room, but it’s a convenient way to communicate the intention behind the product. I think ‘speaker calibration’ products would be much harder to market.

Myth 5 - Your Mixes Need To Be Loud To Be ‘Competitive’

In spite of all the work done by this blog and the tireless efforts of Ian Shepherd at Production Advice the myth that loud mixes give an advantage and allow mixes to stand out from their competition persists widely. Perhaps surprisingly it seems to be members of the production community themselves who are largely responsible for this myth being perpetuated, with misconceptions such as loud mixes being a requirement for certain genres being very common.

These ideas are often a result of people failing to understand that loudness and the sonic signature of audio which has been aggressively limited for stylistic reasons are independent considerations and mastering to loudness targets which make dynamic range headroom available doesn’t preclude the use of heavy limiting. Additionally with loudness normalisation in place on streaming platforms attempts to master to ‘competitive levels’ (i.e. very loud) are self-defeating as the streaming platform will attenuate the loud mix to sit at the target loudness.

Some commentators online present the ability to switch off the loudness normalisation in streaming platforms and hear the ‘competitive advantage’ of loud mixes but there is little evidence that many users actually do this apart from producers seeking justification for their ‘louder than yours’ tracks!

What audio myths do you think need debunking? Share your thoughts in the comments.

Stairstep image courtesey of PS Audio