What is RMS?

Earlier I was reminded by a Facebook friend of 60′s/70′s blues rockers Canned Heat’s old “RMS is Truth!” bumper stickers. Someone in the thread asked for a translation and the original poster recounted the Heat’s advocacy of RMS amplifier power output ratings vis a vis other, more ‘marketable’ spec standards.

Root-mean-square. It’s a power averaging method. As noted, it was used by electronics manufacturers with some integrity, while many others used ‘BS’ ratings like ‘peak power.’ 

One place where you may see it increasingly is in ‘smart levelling’ systems for multimedia playback. 

We’ve all likely had the experience of listening to some nice, classic Billie Holiday at a comfortable level in our play shuffle and then some Skrillex comes on and pins your eyeballs into the back of your skull and your ears into the next dimension. 

The deal is that digital formats have a ‘maximum peak loudness’ (0 dB FS [full scale]) that essentially is the loudest the device can put out. Some material is loud all the way through (or mostly) like Skrillex — the producers have intentionally used extreme settings on one or more compressor/limiters to make all the quiet bits as loud or nearly as loud as the quiet bits. (Now, Skrillex has ‘dynamics’ in the sense that it’s almost full loudness through most of the song but has big level ‘drops’ inserted strategically through the course of the song, presumably to keep attention in focus, since the music is otherwise so mind-numbing. J/K.)

So, even if that Billie Holiday record’s loudest bits are every bit as loud as the Skrillex, on average, the level is much much lower.

How much? Such average levels are typically measured in dB RMS. A difference of 6 dB can be said to be equivalent to a doubling of volume.

That Billie Holiday record might have an RMS average level of, let’s say, -18 dB RMS (particularly if it was mastered for CD before the ‘loudness wars’ era of the late 90s on; Skrillex’s big hit (something about Sprites I think) has an RMS average of around – 6 dB RMS. 

That means that the Skrillex record will seem to you to be about FOUR TIMES as loud as the Billie Holiday. (12 dB difference; each 6 dB is about equivalent to doubling perceived loudness.)

Awesome, eh?

In the studio: Is the Customer always right?

Artists compromise at the risk of their art.

Recording engineers compromise at the risk of pleasing their talent.

Now, it’s probably only sensible that, as an engineer on a studio session, you should notify and tactfully let a producer, artist, or other client know if he’s making a mistake. But what if he wants to do it anyway after you’ve briefly explained the situation?

Let’s see how that breaks down for recording engineers working for others:

You can waste time arguing with and trying to persuade the client, possibly sabotaging the relationship between technical staff and producer and/or talent — OR you can please the client now when there’s customer satisfaction and possibly even payment at stake if you don’t.

Of course, for sure there is ALSO the risk of pleasing the talent in the short term — but having them realize years down the road, that your dutch uncle warnings were right all along.

But is that really so bad?

They were happy when they paid you. It’s now a couple years later, they’ve realized maybe you were right when you suggested one path but they took the other and what’s the end result?

Either that makes you look even smarter in their eyes — OR they are the sort of folks who will then turn around and bitterly blame you for not arguing harder to keep them from their mistake — and how much do you really want to keep clients like that?

A note on this advice… 
The words in this blog post above are mine. But the practical wisdom and situational logic it attempts to illuminate are from others who I’ve read or talked with over the years. Just passin’ it along.