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Boom Mic sounding low, cranking up trim Nomad-6


Mike Wally

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Has anyone else found they need to crank the trim all the way up using a Boom Mic? I use a Sennheiser 416, Phantom Power is on. I just always seem to be cranking the trim all the way up. Is there a setting I'm missing, input limiters or something like that that I should check on? Thank you.

-W

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Hmm..maybe there is a different area to set phantom voltage. On SD gear, typically can switch between 12 and 48 to allow using only as much juice as necessary. I would imagine there is either a menu or switch to select that on Nomad.

but i have had the same symptom with underpowering phantom

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I did not use a meter, no. I called Pro-sound, and Jason said that there is no option for 48v, that Phantom On just means 48v, there's no setting for T power or 12.

Yea, I haven't maxed it, but getting into the +20 trim is concerning I guess. Though, Jason mentioned that the numbers aren't entirely accurate.

I'm keeping my headphones at 12'o clock, is that what you're doing Max?

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Zaxcom did not make the Nomad with a 12 volt option so its phantom power is indeed 48v.

Have you tried other microphones to verify it isn't an issue with the mic? Swapped out cables?

www.matthewfreed.com

Production Sound Mixing for TV, Films, and Commercials

I haven't, but will try to do so.

Where is your trim set with an external phantom supply?

Haven't tried it with an external phantom..

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I was a bit confused by the gain numbers not corellating to a specific amount of gain when I first got my nomad, but through some posts here I learned that the gain numbers are arbitrary. It took me a while to get used to it, but now I don't bother looking at the gain setting, I just set according to my meters. So far I've always been able to get plenty of gain even on quiet scenes. I'm using a 416 and a cmc641.

http://wanderingear.net

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I generally run the trim levels for both my Schoep's and Sennhieser's in the range between 18-21. As already mentioned here the trim number is essentially an arbitrary number and doesn't really correlate to anything. The trim will go to 30 - so you still have plenty of room to go. As a test try turning the trim to 30 and see how much gain you have. My guess is you will have more than you will ever use.

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Here's a tip: Try the boom mic on each input. You'll see that it needs less gain on other Inputs. If you're happier with another, louder input, just use that one for the boom and re-route accordingly. But if you can get enough gain (even if you max it) out of your Input 1 just leave it there. Don't worry about the noise floor, as the Zax preamps are pretty quiet.

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Some of this confusion may stem from a lack of understanding about what decibels are.

Decibels do not specify an amount or quantity. They specify a ratio. In our case, we're talking amplitude ratios.

Saying a gain level is set at +6dB is similar to me saying "I have twice as much money."

Twice as much as what?

If I say I have twice as much money as this morning when I had ten dollars, using the ratio and the knowledge of what it's referenced to, you'd know how much money I have (which is more than I know, but that's an entirely different matter).

That's why, when it's appropriate, you'll see decibels written as dBm or dBu or dbv, or dBV, where dBm refers to the voltage it takes to dissipate 1 milliwatt of power in a load of 600 ohms (which is .775 volts RMS). Proper power transfer and impedance matching was important in the days of long distance analog telephone lines. These days, we more often use bridging circuits, no longer matching the impedance of the output circuit at the input to the device being fed, but rather feeding unloaded -- i.e. at least ten times higher impedance -- inputs. Therefore, dBu (the "u" meaning "unloaded") simply refers to an RMS voltage level of .775 volts.

Okay, this last paragraph is probably TMI if you're not a professional sound mixer who wants to intimately know what's happening with the signal levels in his/her circuits. So, just remember that decibels are a ratio. In the discussion at hand, this comes into play by the fact that there is more than one thing in each input signal path that adjusts the gain. That's why that gain number mentioned earlier is arbitrary. Whereas, even if it were a calibrated control, it is still relative to everything else you're doing to the signal gain-wise, therefore, it can't be treated as a quantitative level.

FWIW: (if your eyes aren't too glazed over by now) In acoustics, decibels often appear as a quantitative figure. This is because of a general understanding that their ratio is referenced to what's considered the "threshold of hearing."

For more information: http://en.wikipedia.org/wiki/Decibel

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Would it be accurate (& more simple) to say the additional + gain is on top of whatever the default/base gain of the preamp is..making it a relative term?

Not really accurate, no. The gain control is part of what sets the gain of the preamp, whether it's single-stage or multi-stage. Each gain stage of a mixer has gain control elements which set the gain of that stage. Those elements can be either fixed or variable, or both. Then, there's passive level control, or an attenuator, which simply adjusts the amount of signal fed to a succeeding stage.

For the best use of any device, you want each stage to be operating at its optimum. I would offer that "optimum" is operating as far from the noise floor as possible while still retaining sufficient headroom to handle signal peaks without distortion.

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I've got the same low gain issue with my Cmit5u and reassigned inputs, outputs and card tracks for a instantant solution.

My setup on Nomad 8 with a Cmit5u is:

Put Cmit5u into channel 1(any one of 6 phantom inputs) to engage phantom power and pass the audio signal to Xlr Out 1 and remove the route Channel 1 to Card Track on the Bus Routing Menu. And hardwire the xlr out 1(line level) to Return 1(line level) with a short cable. Now I assign the Return 1 to Card Track 1.

For this I have to give up one Return Channel but now have enough gain on such a low sensitive mic.

If this routing is possible all softwarely, that should be more than wonderful.

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I've got the same low gain issue with my Cmit5u and reassigned inputs, outputs and card tracks for a instantant solution.

My setup on Nomad 8 with a Cmit5u is:

Put Cmit5u into channel 1(any one of 6 phantom inputs) to engage phantom power and pass the audio signal to Xlr Out 1 and remove the route Channel 1 to Card Track on the Bus Routing Menu. And hardwire the xlr out 1(line level) to Return 1(line level) with a short cable. Now I assign the Return 1 to Card Track 1.

For this I have to give up one Return Channel but now have enough gain on such a low sensitive mic.

If this routing is possible all softwarely, that should be more than wonderful.

Direct output bus routing is coming in the near future.

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I did not use a meter, no. I called Pro-sound, and Jason said that there is no option for 48v, that Phantom On just means 48v, there's no setting for T power or 12.

Yea, I haven't maxed it, but getting into the +20 trim is concerning I guess. Though, Jason mentioned that the numbers aren't entirely accurate.

I'm keeping my headphones at 12'o clock, is that what you're doing Max?

I use the CMIT 5U with my Nomad and haven't noticed an issue with low gain. I usually use channel six for my boom. Is the trim maxed out at +20 ( I don't have mine in front of me to look)? I do have to ride it pretty high but can't remember what it usually ends up at. Still sounds clean so I don't pay too much attention. My phones are generally set between 1 and 2 o'clock if mixing quieter stuff and noon if its noisey.

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I've got the same low gain issue with my Cmit5u and reassigned inputs, outputs and card tracks for a instantant solution.

My setup on Nomad 8 with a Cmit5u is:

Put Cmit5u into channel 1(any one of 6 phantom inputs) to engage phantom power and pass the audio signal to Xlr Out 1 and remove the route Channel 1 to Card Track on the Bus Routing Menu. And hardwire the xlr out 1(line level) to Return 1(line level) with a short cable. Now I assign the Return 1 to Card Track 1.

For this I have to give up one Return Channel but now have enough gain on such a low sensitive mic.

If this routing is possible all softwarely, that should be more than wonderful.

You can use the card limiters to add gain to your card tracks if your input gain is maxed out.

http://wanderingear.net

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  • 11 years later...

So still a bit confused on what the best practices are if you have maxed out gain on an input (usually coming from a boom mic).  Just to summarize the only thing you can do on the Nomad is use the card limiters to add gain to the card tracks or see if another input is louder by chance?

 

I also noticed that you can also add digital gain to analog inputs. Maybe there is a more up to date thread Im missing?

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