#1 Microphone gain settings on a transmitter
Hi friends,
In most television shoots in Mumbai, India, we use Sennheiser G3 or G2 transmitters. I have come across many engineers, who set the input gain settings incorrectly on a transmitter.The tendency is to set it pretty high, with the result that when the talent shouts or screams, the transmitter input stage gets overloaded with a very hot signal, which it cannot avoid but DISTORT. It is this DISTORTED signal which is transmitted and received by the receiver. Once heavily distorted, it cannot be repaired and made UNDISTORTED.
On so many television shows, specially the daily soap type of shows in India, we hear badly distorted sound on telecast. This reflects poorly about our quality standards.
If enough headroom is kept at the transmitter input stage, we can very easily avoid distortion. The best way to set levels on a transmitter is by speaking loudly (or even shouting loudly) at the mic and then watching if the input is clipping or peaking on the transmitter. If clipping or peaking happens, reduce the signal going into the transmitter till no clipping or peaking occurs (or that it occurs very occasionally). On normal dialogues, this will result is a low level being shown on the meters. But do not worry. You can always push gain up at a later stage in the mixing console or in post.
Your receivers output level should be matched to your mixing consoles input. I have seen many recordists take a line level output from a receiver and patch it to a Mic In on a console. This can result in a very hot signal being received by the console and hence, the input stage of the console could get overloaded. Yes, at times, it works well, but there is always the danger of exceeding the parameters of the input stage of the console. You also end up having very little to play with on the input trim pot of the console.
The thing to keep in mind is this. WHEN A TALENT IS TALKING, HIS LEVELS WILL VARY A LOT - AT TIMES BY AS MUCH AS 20 TO 25 DB, AND THEREFORE, WE NEED TO KEEP ENOUGH HEADROOM AT THE TRANSMITTER TO TAKE CARE OF THIS HUGE VARIATION IN LEVELS. Once we receive a clean undistorted signal into our console, we can TAME the signal by using a compressor, so that the variations in level are kept in check. A properly compressed dialogue track will sound very good as compared to a distorted and wildly varying dialogue track.
If the recordist does not have access to a compressor on his mixer or recording device, he should record with the same amount of headroom. The compressor to level the audio can be inserted and used in post, by the sound editor or mixing engineer.
That brings me to another misconception that most television editors in Mumbai have. The minute they see slightly low levels on the NLE (like FCP or Premier), they panic and start mumbling about poor recording levels. They will duplicate tracks (sometimes as many as 5 times) to get a 'desired' level in their system. Most don't know that they can NORMALIZE a track, if levels are a bit low.
An editor needs to understand that in a daily soap kind of shoot, where the recordist is sitting with a very basic mixing console (with no good compressor), it is better if he records a bit low and leaves enough headroom. It is only now that we see Sound Devices 664 and other such recorders being used on television shows. Hopefully, things will start improving soon.
Until next time...
CC
E-mail: cheerag.cama@gmail.com
Twitter: @cheragc
Website: www.cheeragcama.com
In most television shoots in Mumbai, India, we use Sennheiser G3 or G2 transmitters. I have come across many engineers, who set the input gain settings incorrectly on a transmitter.The tendency is to set it pretty high, with the result that when the talent shouts or screams, the transmitter input stage gets overloaded with a very hot signal, which it cannot avoid but DISTORT. It is this DISTORTED signal which is transmitted and received by the receiver. Once heavily distorted, it cannot be repaired and made UNDISTORTED.
On so many television shows, specially the daily soap type of shows in India, we hear badly distorted sound on telecast. This reflects poorly about our quality standards.
If enough headroom is kept at the transmitter input stage, we can very easily avoid distortion. The best way to set levels on a transmitter is by speaking loudly (or even shouting loudly) at the mic and then watching if the input is clipping or peaking on the transmitter. If clipping or peaking happens, reduce the signal going into the transmitter till no clipping or peaking occurs (or that it occurs very occasionally). On normal dialogues, this will result is a low level being shown on the meters. But do not worry. You can always push gain up at a later stage in the mixing console or in post.
Your receivers output level should be matched to your mixing consoles input. I have seen many recordists take a line level output from a receiver and patch it to a Mic In on a console. This can result in a very hot signal being received by the console and hence, the input stage of the console could get overloaded. Yes, at times, it works well, but there is always the danger of exceeding the parameters of the input stage of the console. You also end up having very little to play with on the input trim pot of the console.
The thing to keep in mind is this. WHEN A TALENT IS TALKING, HIS LEVELS WILL VARY A LOT - AT TIMES BY AS MUCH AS 20 TO 25 DB, AND THEREFORE, WE NEED TO KEEP ENOUGH HEADROOM AT THE TRANSMITTER TO TAKE CARE OF THIS HUGE VARIATION IN LEVELS. Once we receive a clean undistorted signal into our console, we can TAME the signal by using a compressor, so that the variations in level are kept in check. A properly compressed dialogue track will sound very good as compared to a distorted and wildly varying dialogue track.
If the recordist does not have access to a compressor on his mixer or recording device, he should record with the same amount of headroom. The compressor to level the audio can be inserted and used in post, by the sound editor or mixing engineer.
That brings me to another misconception that most television editors in Mumbai have. The minute they see slightly low levels on the NLE (like FCP or Premier), they panic and start mumbling about poor recording levels. They will duplicate tracks (sometimes as many as 5 times) to get a 'desired' level in their system. Most don't know that they can NORMALIZE a track, if levels are a bit low.
An editor needs to understand that in a daily soap kind of shoot, where the recordist is sitting with a very basic mixing console (with no good compressor), it is better if he records a bit low and leaves enough headroom. It is only now that we see Sound Devices 664 and other such recorders being used on television shows. Hopefully, things will start improving soon.
Until next time...
CC
E-mail: cheerag.cama@gmail.com
Twitter: @cheragc
Website: www.cheeragcama.com
Good Start Cherag....but I want to add one thing to this is that since the main focus is/was on capturing location sound for TV series, I bet most of the recordists haven't heard the term unity gain while checking or aligning there mic.s and mixer and recorder etc...ya poor quality gears is another issue as it prevails like chalta hain or chala lenge kind of attitude....and the most hated and ignorant persons are the editors of TV series who handle location sound....they know nothing about sound and how to handle in post and the producer listens to those in-house or freelance idiots and the onus then turns to the location sound recordist. This is horrible, same trend is going and nothing will be changed unless the sound is handled by some responsible persons - not an attendant turned recordist - both location as well as post production or an editor ignorant about sound. Period.
ReplyDeleteSorry, this is me, Subhashis Roy.
ReplyDeleteWell written chief, but the issue here broadly is lack of "Trained professionals" handling Audio on film/TV sets. If they were to know of terms like 'headroom', 'unity gain', 'compressor', 'dynamic range', I'm certain they would've been applying fundamentals while recording. Most of engineers I've seen/heard about on TV sets are operators without basic knowledge of recording fundamentals. Most of them wouldn't even know if a G3 gives a line out or a Mic out. Operating a SD 664 does not make one a Sound recordist.
ReplyDeleteWhat you say is quite true. In the past, there have been a lot of 'attendants' who have graduated to become 'recordists'.
DeleteBut of late, we are getting students passing out from the multitude of Media Schools and trained as Sound Engineers. Unfortunately, they do not get sufficient training in multi-camera television work and the focus in these Media Schools is more on learning ProTools. So they will have to learn on the job.
At the outset, I have not worked on the Sennheiser G series for years. What I am going to say based on my experience on Lectrosonics which is what I've been using for many years now.
ReplyDeleteYes I agree that it is good to be conservative when setting levels on the transmitter. Anything distorted there is unsalvageable. I just want to warn about setting TX levels too low. Like in any system there is the danger of getting into the noise floor. Also if one sets the transmitter gain too low it negatively affects the operating range of the wireless system. The best way to set to TX level is to tickle the limiter and then back off a bit so that you don't over modulate the TX.
Thanks Cherag for starting this. I hope it will be a lively place for exchanging notes.
Sorry that was Suresh Rajamani
ReplyDeleteHi Suresh, you are absolutely right about Lectrosonics Tx needing to be set just below limiting, or else it affects range. It's just that I have seen many recordists massively overload the Sennheiser Tx and I don't think that is right. And off course, setting gain too low is also not good. Hope I am making sense! Thanks for your comments. 😀
ReplyDelete