MLB’s fall sports classic is over. ESPN, TBS, and Fox Sports all had excellent coverage, but I’ve often wondered why the same sport, played in similar outdoor stadiums, with a very aggressive mic plan all sound different. Is the tone of the program different because of the transmitter or mixer?
Live audio and especially live sports sound can be a big challenge as audio is often unpredictable and hard to tame and there is usually no dress rehearsal before you take to the air – and even then there are the audio gremlins.
With mandatory loudness requirements and a wide digital audio dynamic range it seems like the oldest instrument in the audio toolbox, the compressor/limiter gets a good workout. I was always confused when my BBC friends said how over-compressed and choppy-sounding live American television sport was. And you know what – I think the criticism is justified.
A compressor squeezes the wide range of volume levels (dynamic range) that captures and combines sports in a fixed pipeline. Obviously, this process sets the tone of the audio signal, with significant consequences. Before the days when each audio channel and group had its own compressor, compressors were usually patched across the mix groups and affected all the sounds in that mix group. Compressing the groups or master channels is usually a compromise between many sound sources with different dynamic characteristics and can easily result in audible pumping from overcompression.
Compressors have a threshold that tells the compressor where to start the process, a ratio control that sets the amount of compression, along with a control for the effect’s attack and release time. Threshold, compression ratio, attack and release are determined by the dynamics of the sound source, but ultimately the ears of the sound mixer should be the test.
I know you’ve heard overcompression or mis-adjustments when a sharp sound, such as the creak of a bat, triggers a rapid attack on a compressor, reducing the peak volume level. That’s what a compressor does. But my biggest complaint is that there is too often a disturbingly slow return to normal volume levels.
Audio dynamics are also controlled by limiting and gating. Limiting the extreme volume is valuable because when audio becomes too much in the digital conversion, the corrupted data is probably not usable. Gating keeps an audio channel closed until a certain threshold level or event opens the sound channel and passes audio.
Gating can be an automated process where the gate can be adjusted to open at a certain sound level, or a gate can be activated externally by a video switch. In addition, in sports a gated sound can be purely manual and achieved by the dexterity of the audio mixer. The problem with a tight, fast port is that there can be an apparent “sound collision” when that unique sound is added to the mix.
You would have experienced the sound when you hear the football referee’s microphone switch on and off during a football broadcast, or when you hear the sound of the baseball home plate banging as the ball crosses the plate. The sound bump in football seems perfectly natural because the viewer sees the official switch their own sound on and off, but I find sound bumps in baseball disturbing.
Manually bumping the sound to try to amplify the bat’s crevice, hitting the ball on leather, or the umpire’s call is one method of trying to accentuate an important aspect of baseball sound: home plate. As a young mixer novice, I was impressed with the sound of CBS Sports and I definitely noticed the bump in the sound as the ball crossed home plate. I thought that if CBS did it this way, it must be good – and I did.
The degree and artistic difference of the bumping varies between mixers, but with a wireless microphone on the umpire, I seriously question the need to dig deeper into the home plate sound and inevitably create a noticeable sonic boom.
Like the delay/lip sync problem, there is compression at the OB carriage, perhaps during backhaul, or eventually in master control and transmission to the viewer/listener. So it’s hard to be critical of over-compressed audio if I’m not sure of the exact source. If the whole program goes down and up again, the source of the overcompression is probably the master control or in the transmission path.
If there is only a single aspect of the sound, such as the effects mix or just the announcers pumping in and out, then the source of the overcompression is probably the OB bus. If the compression problem occurs during backhaul, in the main control room, or in the retransmission process, the audio mixer in the recording carriage would never hear it, but if the compression is at the recording carriage, the mixer should be able to hear and adjust it. There are many places where things can go wrong.
Sports sound changed when sports games increased the intensity and expectations for in-your-face sound. Since then, there has been a huge push for more sound and sound details, especially during championships and major events. Compressors and blasts are an attempt to entertain and engage the audience and I doubt the phone lines will burn out with complaints of too much compression.
But it’s irritating when it’s repetitive and definitely not necessary. I enjoyed the sound of all the division and series playoffs, but a smoothly balanced soundscape is just as entertaining without any trampoline sound dynamics.