Engineering Basics: Maximizing Detail in a Recording

I’ve come to expect a wide variety of opinions amongst audiophile regarding music formats, equipment, cables and accessories but I like to think that there certain things about our passion that are quite simply right or wrong. Aren’t there things that are just factual…things that you learn in school or after spending 40 years as an audio engineer? Apparently, I’ve been wrong about that assumption. A seasoned reviewer and friend sent me a couple of posts from another audio blog over the past couple of days. Someone that I know and have a great deal of respect for authored them. I’ve owned equipment that he’s designed since my earliest days in business. But whatever talents he brings to his electronics designs are not apparent in his knowledge of basic audio engineering, recording and mastering.

So here’s the start of a few posts that I hope will serve to inform the author and others regarding my side of the music production process.

Let’s start by tackling the issue of “low level detail”, a subject that audiophile reviewers and consumers like to use when writing about a recording or a piece of high-end audio gear. They are simply the lowest level components of a piece of recorded music. Low level details could be reverb tails, high frequency partials, leakage from distant mikes or just quiet musical passages.

There’s a reason they are the lowest elements in a track and they should remain as the lowest dynamic elements. Is there any audiophile or musician that wants the mastering engineer to “rearrange” the timbral palette of their work? I don’t think so. At least that’s what I learned over 13 years of mastering records.

The assertion was made in the referenced post that vinyl LPs can only deliver so much dynamic range…that it is absolutely true. The best that a vinyl record can do is about 50-60 dB and that’s a rare recording. Most vinyl records are down in the 30-45 dB range. However, recall that virtually all commercial CDs are much less than that!

Knowing that vinyl LPs and analog tape have limited dynamic range means that engineers at every stage need to employ tools that reduce the real world musical dynamics to bring them in line with the medium that they are using to record the project. For the source recording, this means using a compressor to bring down the loudest sections. Compressors do this very well and in varying degrees of “gain reduction. They can reduce a signal by 2:1, 4:1 or more (I’ll have to write about compressors in a separate post). What they don’t do is turn up the quietest sounds. There are other devices called expanders that do that…but they are NEVER used in live recordings.

During a mixing session (if required…some live classical tracks are sent straight to the mastering engineer), compression is used for creative reasons. Individual tracks or the entire program can have the dynamic range narrowed because the engineer/artist/producer prefers that sound for whatever reason.

The mastering phase of a production doesn’t employ compression on a track to increase the audibility of “low level details”. The reason compression is used at this stage is to make a track punchy, louder and more dynamically consistent.

But contrary to some of the statement made in the other post, the use of compression in any stage of the production process DOES NOT “improve the ambiance, low level detail and reverberation of the recording space” resulting in vinyl LPs sounding more “live” and “real”…they don’t (you have to listen to one of my tracks for comparison)! Nothing could be further from the truth. In actuality, the more compression applied to a particular recording the more you cloud or blur the individual sounds and therefore you lose “low level detail”. A highly compressed recording (which is most of the recordings you experience today) loses these details because the mastering engineer has just removed one of the parameters (the widest possible dynamic range) that let’s us distinguish between musical elements in a recording…including the reverberation and reflections present in the space (if they are present at all).

Details of any kind in recorded music are the direct result of leaving the natural musical dynamics as performed by the musicians alone. Of course, it’s dependent on the musical genre in question but right now I’m talking about classical or jazz type recordings.

Other choices by the recording engineer contribute to maximizing details as well. We’ll talk about them tomorrow.