Q&A: When Do I Normalize?

Happy new year :-)

Please check out my latest post, and the 1st one with Ask a Sound Guy: Q&A: When Do I Normalize?

Do we need 24 bit audio for sonic nirvana?

"The noise level in the avarage residence is about 43 decibels" [Harry Ferdinand Olson (1967): Music, physics and engineering], whereas a house in the country can be as quiet as 35 dB. Let's deduct 6 dB from that number as it is quite possible to discern musical content that level-wise lies within and seemingly should be masked by the noise floor.

16 bit audio has a theoretical dynamic range of 96 dB, which, if you add that onto the baseline 29 dB amounts to a peak of 128 dB, slightly below the threshold of pain. It seems to me that that span should suffice to adequately present the finest dynamics inherent in music, especially since the range I usually experience recording very high dynamic range avant-garde music lies at 54 dB, and many real-life concert venues have a noise floor at -60 dB FS. Of course less is highly preferable, but then it is also dependent on the quality of the ambient noise.

Note the use of the word "suffice". Clearly, having a theoretically usable resolution of 144 dB when working with (real) 24 bit audio is even better. It is tantamount when recording music while leaving adequate headroom--with no manual gain riding required and no need to use a compressor while tracking--, and during mixing to avoid introducing distortion while processing.

But once you are done, dithering carefully to 16 bit will be OK.

Andrew Levine's DAW-history

In 1995, while in the process of obtaining my M.A. (in Computational Linguistics & Cognitive Psychology) I started developing multimedia applications. Being a dedicated Macromedia user I did all sound editing in SoundEdit 16 that came as part of the Director bundle. At some point DECK II joined the fray, originally developed by OSC for Digidesign, later sold to Macromedia and finally dropped by BIAS.

DECK was originally used for four track hard disk recording with synchronous MIDI recording and playback. Original DECK also offered moving fader automation, digital mix-to-disk, and unlimited, non-degrading track bounce. Among other awards, DECK (and DECK II) won the 1990 and 1993 MacUser Eddy awards for best music and sound software. [Link]

When in 2002 I got serious about "sound" I first delved into Protools LE that came with the 2ch MBox. While I liked the ergonomics of that GUI I quickly realized that

• I wanted to move to OSX now that a UNIX-kernel had (finally) become the basis of the Mac OS
  (I used to be a fan of the BeOS; the Wikipedia article states that "iZ Technology sells the RADAR 24, a hard disc-based, 24-track professional audio recorder based on BeOS 5."--amazing!)
  
• I'd want to record more than two channels
  
• Using a Protools system kept you locked to one hard-&software combination

In any case, I returned the MBox and after researching my options ordered a 2882+DSP by Metric Halo and Digital Performer by MOTU, which (as version 4.0) was the first OSX-based DAW on the market.

As with most complex programs it took me a while to get fluent in DP. I stayed with it for several years / iterations (DP 3.x, 4.x, 5.x, 6.0--that one I returned) until I ran into some serious issues, the worst being that with complex projects the engine would not play back the pieces of audio I saw on screen. You can imagine that it made editing quite painful, and I was in the middle of an editing-intense project (Debussy Préludes).

I managed to trudge along for a while, but when a friend suggested I try out the newly revamped Logic 8 I went for it. Luckily for me I used the DAW mostly for editing and as a "tape machine". I used to mix, process & master all projects mainly within the MIO's (Metric Halo's MobileIO interfaces) DSP-matrix. With the advent of the 2d-architecture that became even easier, even when I started moving into the surround realm. But still, the paradigm and handling of Logic was so much different from the one of DP that I enjoyed going back to old (working!) DP-projects from time to time.

And then came Reaper by Cockos.

Floris van Manen, a longtime net-acquaintance and friend of mine had been suggesting I give Reaper a try for ages, and it had been growing to be more and more feature-complete on OSX as time passed. So I finally decided to give it a spin with several new, not especially time-critical projects--and I got hooked!

Reaper features...

• a newly designed audio engine, that sounds so good I moved from realtime-bouncing to DAW-rendering for most projects
  
• a very comfortable GUI, that is even skinnable
  
• an editing paradigm that is very smooth and that I got used to in next to no time
  
• amazing support, both from the user community and the developers
  
• all at an unbeatable price

How can you go wrong? The last iteration since I registered has introduced Redbook-CD-rendering, yet again streamlining my workflow, and fixed some small bugs that I had came accross. You just don't get that level of responsiveness from any of the big DAW-companies.

So, if you have not already done so, give Reaper a spin. I see myself happily sticking to this platform for a long time to come :-)

Tracking festivals

I just noticed that it's been a while since my last blog entry. I guess there was too much "real" work to be done :-)

In any case, having just finished recording six 90 min concerts and one open podium event at the International Jewish Music Festival 2009 in Amsterdam I'll share some thoughts on covering festivals. In this case I was not only in charge of the recordings but also fed the guys handling the sound reinforcement all channels requested by the ensembles.

• There has to be one, and only one person in charge of the overall procedure.
  
• Organisation is key. The mikes have to be placed, patched to clearly documented lines & tested for functionality, the gain is determined for optimal signals, then the levels for the SR are set before running an overall soundcheck.
  
• Prepare well in advance and still stay flexible.
  
• Collect the ensembles' set lists right after each performance, make sure they are correct, and perhaps even ask for the musicians' opinions regarding which titles they felt especially good (or bad) about.

Always remember: the recording comes first--at least that's my take on things :-) The record of the music is the one thing that remains and can be re-listened (to), and as such it is always good practice to keep the FOH volume as low as possible and avoid stage monitor bleed in your main mic setup.

Mini-DV-Cameras with 5.1 surround?

I have been seeing Mini-DV-cameras that are advertised as having a "5.1 channel surround sound microphone". The Sony ECM-HQP has been around as an add-on. SonyStyle says: "It features the capability to record up to four channels of high quality audio for clear, distinct voices and life-like sounds. [...] Offers 3 modes for recording: 5.1 channel Surround mode; 4ch MIC mode;" --mode 3 is sadly missing in the description.

Well, let me tell you it just won't work ;-)

Getting stereo "right" is not trivial, and achieving a soundstage that corresponds with the repertoire, ensemble & performance space gets even more complicated. This can not be achieved by any suit-all clip-on solution--and this goes even more for an enveloping surround soundstage. Recording music & ambience well requires accurate planning, based on plenty of experience, and adapted to the specific situation.

It's like the old joke about how to get to Carnegie Hall. The answer is _not_ to just grab an instrument & a map. Why, even a GPS will only do you so much good.

The C-trilogy (Part 2) - Center, where are you?

[Continued from Part 1]

Like I said before: "What you want to do is find a spot where you'd place the one microphone required for a monophonic recording."

There are collegues that insist that the center is reserved for instruments that can be heard from the middle of the ensemble, but this makes sense primarily with small groupings. As soon as the ensemble is wide and deep it becomes difficult to determine--without examining the music in depth.

One possible creative idea would be to enhance transparency by placing various spot-miked sources in the center, delayed to let the original impression (from the space between the two front speakers) come first and steer the perceived source in that direction utilizing the Haas effect.

The single microphone used to derive the center will most likely be placed not far off the central axis, and rather close to the ensemble. Since we are dealing with a discrete channel Lou Burroughs' "3:1-rule" must not be taken into account--except for the situation in which you might want to experiment with adding some of that signal to a stereo mix.

The C-trilogy (Part 1) - Center, who are you?

According to Wikipedia "It is the channel that is mostly, or fully, dedicated to the reproduction of the dialogue of an audiovisual program. [...] In material without accompanying visuals (eg music), the center channel simply reproduces sound intended to come from immediately in front of the listener."

The center channel serves to anchor the phantom image which widens the sweet spot for listeners. On the other hand leaving a discrete--and required--signal out of the L+R channels will cause a problem if the C channel is not configured correctly. Insofar many engineers also feed this material to L+R. See the discussion @ mixonline.

In the C-trilogy I'll do some thinking aloud about (1) which microphone to use, (2) where to place it and (3) how to add it to the mix.

Which microphone to use to supply a discrete signal for a dedicated center channel?

Sidetrack: I say "discrete signal" because with coincident main microphone setups (XY & Blumlein; M/S provides you with a dedicated C anyway) you can easily extract the sum of L+R and place that onto the C. This works slightly less good with near coincident arrangements (ORTF) and not at all with time of arrival based / AB setups.

What you want to do is find a spot where you'd place the one microphone required for a monophonic recording. True, this skill has been steadily devalued, but attempting it lets you appreciate stereo and surround all the more--and gives you something fitting the C.

• Cardioid: A microphone of cardioid characteristic attenuates sources arriving off angle. Using one will work only if the ensemble does not expand far in width and depth. On the other hand you will attenuate sound sources from behind the microphone, e.g. favorably reducing audience noise.
  
• Omni: I generally consider an omni, with a uniform frequency response in all directions, to be a good choice to track a dedicated center, especially if it can be placed close to or centrally within the ensemble.
  
• Bidirectional: A fig-8 can also be used facing sideways in a close frontal location, but not centrally within a heterogenous soundfield, e.g. an instrumental ensemble. It works well for a choir, attenuating vocalists singing towards the mic as well as sound / noise coming from the direction of the audience (and conductor).

When recording repertoire with one soloist a close spot can also be fed to the C, suitably delayed (in relation to the main microphone) if you don't want to pull the soloist to the middle--which can be an option on occasion. You'll probably want use a directional mic in this case to have greater control over the pickup range, but if you are close enough an omni will work as well.

[Continued in Part 2]