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Setting wireless lavs for dialog (mic level vs. line) what's your preference?


José

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Hi guys, 

 

Sorry for bring this topic back up again. 

I got this situation, where the presenter was shouting all the time. My SMa was down to -15 or -10. I got heavily distorted limiter audio while he was shouting in the scene. At that moment, I could not figure it out why I was getting poor audio. However, the second day, I have noticed that on the receiver LCD (Gain Arrow meter getting lots of squares) which indicated overloading. 

I changed my receiver's level down to -20db from +5. The overloading square on the LCD disappeared, and limiter was not engaged all the time or not as I noticed. 

 

I thought on the receiver (UCR411) no matter I set -20, or +5, it would take the full range of the audio...however, if +5 will cost easy overload on the receiver side. I would rather choose the saver setting.... 

Sorry about my poor english, hopefully that makes sense. 

 

What I meant was  +5 (Line Level) might cost overload on the receiver itself.  Mic line, might avoid this problem OR may be I already got the overload audio from my sanken COS11D at first place. 

 

Cheers

Hiro

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Hi guys, 

 

Sorry for bring this topic back up again. 

I got this situation, where the presenter was shouting all the time. My SMa was down to -15 or -10. I got heavily distorted limiter audio while he was shouting in the scene. At that moment, I could not figure it out why I was getting poor audio. However, the second day, I have noticed that on the receiver LCD (Gain Arrow meter getting lots of squares) which indicated overloading. 

I changed my receiver's level down to -20db from +5. The overloading square on the LCD disappeared, and limiter was not engaged all the time or not as I noticed. 

 

I thought on the receiver (UCR411) no matter I set -20, or +5, it would take the full range of the audio...however, if +5 will cost easy overload on the receiver side. I would rather choose the saver setting.... 

Sorry about my poor english, hopefully that makes sense. 

 

What I meant was  +5 (Line Level) might cost overload on the receiver itself.  Mic line, might avoid this problem OR may be I already got the overload audio from my sanken COS11D at first place. 

 

Cheers

Hiro

Hi Hiro,

There is something else going on here. The receiver audio runs wide open at all times. Call it +5 for ease of discussion. When you reduce the output level to -20, you are simply applying a 25 dB resistive attenuator to the +5 output to lower it to -20. If the receiver overloaded at +5 it would overload exactly as badly at -20. We did this to keep life simple for the users or at least simpler. The square symbol on the receiver does not indicate clipping, overloading or distortion. It simply indicates that the transmitter is getting close to full modulation and the compressor at the input stage of the transmitter is beginning to reduce the input signal of the attached microphone. The microphone (COS-11) can still be overdriven but the transmitter will not over-modulate.

 

Reading your post, you said turning down the receiver level reduced the overloading evidenced by the square symbol. Turning down the receiver will not change the symbol's indication. That symbol shows transmitter deviation and has nothing to do with the receiver level setting. So, something changed at the transmitter, otherwise the square wouldn't have disappeared. The change could be the transmitter gain setting, the mic placement or the presenter going hoarse from sustained shouting. The receiver setting had nothing to do with it.

 

The fact that the distorted audio disappeared when you attenuated the output of the receiver would normally indicate that something after the receiver was overloading and the reduced output was no longer overdriving that following unit. However, you said the square symbol disappeared which indicates something changed at the transmitter side.

 

In sum, if the transmitter and receiver are not broken, if the emulations match (IFB vs 400) and  if the series match (200 vs Euro 300 or 400 vs Euro 400), the receiver cannot overload with any output setting.

Best Regards,

Larry Fisher

Lectrosonics 

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Hi Hiro,

There is something else going on here. The receiver audio runs wide open at all times. Call it +5 for ease of discussion. When you reduce the output level to -20, you are simply applying a 25 dB resistive attenuator to the +5 output to lower it to -20. If the receiver overloaded at +5 it would overload exactly as badly at -20. We did this to keep life simple for the users or at least simpler. The square symbol on the receiver does not indicate clipping, overloading or distortion. It simply indicates that the transmitter is getting close to full modulation and the compressor at the input stage of the transmitter is beginning to reduce the input signal of the attached microphone. The microphone (COS-11) can still be overdriven but the transmitter will not over-modulate.

Reading your post, you said turning down the receiver level reduced the overloading evidenced by the square symbol. Turning down the receiver will not change the symbol's indication. That symbol shows transmitter deviation and has nothing to do with the receiver level setting. So, something changed at the transmitter, otherwise the square wouldn't have disappeared. The change could be the transmitter gain setting, the mic placement or the presenter going hoarse from sustained shouting. The receiver setting had nothing to do with it.

The fact that the distorted audio disappeared when you attenuated the output of the receiver would normally indicate that something after the receiver was overloading and the reduced output was no longer overdriving that following unit. However, you said the square symbol disappeared which indicates something changed at the transmitter side.

In sum, if the transmitter and receiver are not broken, if the emulations match (IFB vs 400) and if the series match (200 vs Euro 300 or 400 vs Euro 400), the receiver cannot overload with any output setting.

Best Regards,

Larry Fisher

Lectrosonics

Thanks Larry for the explanation.

Appreciate your input and help as always!

Hiro

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  • 3 weeks later...

Can anyone name a single professional mixer that is designed this way? Even from a cost-cutting standpoint this design shortcut makes no sense since the invention of the opamp.

Hi John,

The Sound Devices 442 and 302 inputs work in this way.

See here:

http://www.sounddevices.com/notes/mixers/302/302-and-442-with-line-inputs/

Cheers,

S.

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  • 3 months later...

Hi José,

3. Line level signals are 40 dB (+ or -) more immune to ground loop noise or hum loop, RF interference, digital transmission artifacts from the AM component and whatever other weird electrical stuff that can be cooked up in a bag with multiple switching power supplies on different frequencies.

Larry, did you really mean to say line here in #3, or did you mean to say mic levels are 40db more susceptible?

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Oh I see, I actually read it wrong. I read "more susceptible," but Larry wrote "more immune." Never mind, thank you.

Aided and abetted by my habit of inserting comments in parenthesis (for better or worse) in the middle of a train of thought.

Best,

Larry F

Lectro

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<<We do have the headphone level output available from the DX2040 which has been successfully used by many freelancers to connect to the Cantar and also the Sound devices products. There is no penalty in quality, but it is unbalanced.>>

 

 

There is a palpable difference between the main (mic level) output and the headphone level output in the 2040. Probably due to the fact that the main output is transformer balanced and the headphone output goes out of an op-amp. 

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