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Author Topic: Low Keyboard Signal Strenth at Live Events  (Read 915 times)

Debbie Dunkley

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Re: Low Keyboard Signal Strenth at Live Events
« Reply #10 on: August 20, 2019, 02:01:40 pm »

Yes Bob.  I just did so and the 21db difference is still there.  No wonder the FOH mixers have complained of low signal strength.  Not certain but I believe 21 db equates to a factor of 126 in signal strength!   

Could this be related to impedance mis-matching?  Not that I know anything about that.   

Like Rob said, are you using the 1/4" or XLR mic ins to your studio mixer? This will make a huge difference.
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A young child says to his mother, "Mom, when I grow up I'm going to be a musician." She replies, "Well honey, you know you can't do both."

Don Martz

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Re: Low Keyboard Signal Strenth at Live Events
« Reply #11 on: August 20, 2019, 02:05:17 pm »

Is the 1/4 on your mixer a line in or a mic in? Taking a keyboard out directly to a mic in will be a hot signal.
Hi Rob.  The 1/4" mixer inputs on the Yamaha are balanced line in with a stated impedance of 50 kohms.
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Art Welter

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Re: Low Keyboard Signal Strenth at Live Events
« Reply #12 on: August 20, 2019, 02:05:41 pm »

I applied a mono patch (so as to ensure L and R are identical signals out of the keyboard) and checked the difference in signal strength between the two paths at the mixer.  21db difference!   The DI box setup results in a 21db lower signal strength than I get going directly into the 1/4" inputs on the mixer.  What on earth is going on?       
Transformation!

The transformer of a passive DI should provide a reasonably high input impedance (up to around 150kΩ) to the unbalanced instrument source, while also stepping down the signal voltage by about 20dB and providing a low-impedance (150-600Ω) balanced output suitable for driving long lines.

If your usual sound provider's console/DI does not have enough gain, using your own active DI may be required. That said, if you can adjust your keyboard so the passive DI levels are similar to an SM 58 with a strong vocal, no investment needed.
Explaining to the sound engineer that your keyboard will require more gain than a vocal mic may be all that is needed- the console input levels I have seen using passive DI on keyboards has ranged from +20 to -60. I'm always a little leery of cranking an unknown keyboard input way up, afraid that the next patch will erupt like a volcano...   

Art
« Last Edit: August 20, 2019, 02:08:45 pm by Art Welter »
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Don Martz

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Re: Low Keyboard Signal Strenth at Live Events
« Reply #13 on: August 20, 2019, 02:16:50 pm »

Transformation!

The transformer of a passive DI should provide a reasonably high input impedance (up to around 150kΩ) to the unbalanced instrument source, while also stepping down the signal voltage by about 20dB and providing a low-impedance (150-600Ω) balanced output suitable for driving long lines.

If your usual sound provider's console/DI does not have enough gain, using your own active DI may be required. That said, if you can adjust your keyboard so the passive DI levels are similar to an SM 58 with a strong vocal, no investment needed.
Explaining to the sound engineer that your keyboard will require more gain than a vocal mic may be all that is needed- the console input levels I have seen using passive DI on keyboards has ranged from +20 to -60. I'm always a little leery of cranking an unknown keyboard input way up, afraid that the next patch will erupt like a volcano...   

Art
Thanks Art.  So the keyboard "sees" higher impedance at the DI which effectively attenuates the signal around 20db?  Then from there its effectively low impedance on to the mixer, at a much reduced signal strength?   
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Mark Scrivener

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Re: Low Keyboard Signal Strenth at Live Events
« Reply #14 on: August 20, 2019, 02:24:01 pm »

Some pro music gear have switchable output levels - usually -10 dBv and +4 dBu. This might be under a system setting or output configuration menu. I bet your outputs are set to -10 dBv, which would explain why they work fine going to the mic preamps on your mixer. If you can switch them to +4 dBu they will work fine with a passive DI box.

Don Martz

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Re: Low Keyboard Signal Strenth at Live Events
« Reply #15 on: August 20, 2019, 02:53:08 pm »

Some pro music gear have switchable output levels - usually -10 dBv and +4 dBu. This might be under a system setting or output configuration menu. I bet your outputs are set to -10 dBv, which would explain why they work fine going to the mic preamps on your mixer. If you can switch them to +4 dBu they will work fine with a passive DI box.
Hi Mark!  You are correct.  I just looked and discovered system settings deep in the menus for "Output Gain" and "Audio Level" both of which can be increased. (The Output Gain was set a 0.0db but can be adjusted up to +12db.)  This is fantastic and my apologies to Debbie for not finding this earlier upon her same wise suggestion.  With these controls, I believe I can now increase the output to more acceptable levels for live performance using a passive DI and compensate in the studio simply by reducing channel gain.  Art's explanation as to why the two paths are so different in signal strength is great - this forum is amazing. 

Thank you all for your knowledge and willingness to help!

-Don   

 
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Debbie Dunkley

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Re: Low Keyboard Signal Strenth at Live Events
« Reply #16 on: August 20, 2019, 03:09:21 pm »

Hi Mark!  You are correct.  I just looked and discovered system settings deep in the menus for "Output Gain" and "Audio Level" both of which can be increased. (The Output Gain was set a 0.0db but can be adjusted up to +12db.)  This is fantastic and my apologies to Debbie for not finding this earlier upon her same wise suggestion.  With these controls, I believe I can now increase the output to more acceptable levels for live performance using a passive DI and compensate in the studio simply by reducing channel gain.  Art's explanation as to why the two paths are so different in signal strength is great - this forum is amazing. 

Thank you all for your knowledge and willingness to help!

-Don   

Good to hear Don - now be careful when you plug in to your studio board next!!
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Robert Lofgren

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Re: Low Keyboard Signal Strenth at Live Events
« Reply #17 on: August 20, 2019, 03:10:54 pm »

Be aware of that increasing the output gain and audio levels may reduce your available headroom and that it might be possible to clip your output with certain patches.

Hi Mark!  You are correct.  I just looked and discovered system settings deep in the menus for "Output Gain" and "Audio Level" both of which can be increased. (The Output Gain was set a 0.0db but can be adjusted up to +12db.)
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Mark Scrivener

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Re: Low Keyboard Signal Strenth at Live Events
« Reply #18 on: August 20, 2019, 04:00:11 pm »

Hi Mark!  You are correct.  <snip>
Thank you all for your knowledge and willingness to help!

-Don   

Glad we could help. Debbie and Robert make excellent points above....not only do you need to be careful plugging in at the studio without a DI, but double check your patches to insure you still have enough headroom. It might make sense to start using a DI in the studio so you aren't having to go back and forth between two setups.

Don Martz

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Re: Low Keyboard Signal Strenth at Live Events
« Reply #19 on: August 20, 2019, 04:09:13 pm »

Be aware of that increasing the output gain and audio levels may reduce your available headroom and that it might be possible to clip your output with certain patches.
Hey Robert, yes, I will leave at least 6db available and I have already made all my patches very consistent with respect to level.
(I'll probably just increase the output gain while leaving the audio level where it is, or vice versa - I have to read about each option in the manual first.)
Thanks,

-Don
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