Old 06-03-2019, 06:18 PM   #1
Baggage
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Default McOne nos passive monitor controller

Is it normal to loose a few db going through a passive monitor controller?

Also, the left channel/monitor seems like it looses a few more db than the right monitor. Thoughts appreciated.

Thanks!
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Old 06-03-2019, 10:14 PM   #2
DVDdoug
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Quote:
Is it normal to loose a few db going through a passive monitor controller?
Depending on the design you can, but on the Internet it says:
"Zero volume loss, balanced in to out (pot fully clockwise = unity gain)"


That's what you'd expect from a regular volume control potentiometer with no additional resistors or anything.


Quote:
Also, the left channel/monitor seems like it looses a few more db than the right monitor. Thoughts appreciated.
Dual pots never "track" identically (welcome to analog).


A good stereo (dual) pot should be "pretty good'. And as above, there should be no attenuation in either channel at full volume.
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Old 06-04-2019, 08:01 AM   #3
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Originally Posted by DVDdoug View Post
Depending on the design you can, but on the Internet it says:
"Zero volume loss, balanced in to out (pot fully clockwise = unity gain)"


That's what you'd expect from a regular volume control potentiometer with no additional resistors or anything.


Dual pots never "track" identically (welcome to analog).


A good stereo (dual) pot should be "pretty good'. And as above, there should be no attenuation in either channel at full volume.
Thanks Doug. I bought this used on the bay for half of the original cost. I guess I got what I payed for.
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Old 06-04-2019, 09:13 AM   #4
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most monitors have trim pots on the back to solve these problems.

highly recommend doing this with pink noise and an SPL meter
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Old 06-04-2019, 10:17 AM   #5
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Thanks Doug. I bought this used on the bay for half of the original cost. I guess I got what I payed for.
There's a thread about it on Gearlsutz. The only complaints with some new units is just like yours. A bit level loss (which seems normal) and sometimes channel levels not equal (which depends on the quality of the pot used).

Like Doug said, it's inherent in a passive controller.
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Old 06-04-2019, 12:33 PM   #6
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Originally Posted by EpicSounds View Post
most monitors have trim pots on the back to solve these problems.

highly recommend doing this with pink noise and an SPL meter
Thanks for the feedback. What is pink noise?
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Old 06-04-2019, 12:53 PM   #7
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Quote:
most monitors have trim pots on the back to solve these problems.
But, usually there is no attenuation at maximum volume (in either channel) and the mismatch happens only at mid/lower levels. When you change the volume control the left/right balance changes and you can't fix that at the monitors.


Quote:
What is pink noise?
It's a "shhhhhhh" noise that approximates the overall-average frequency spectrum of normal-everyday sound. You can find a sample to download or there are plug-ins that can generate it.


Technically, it's white noise low-pass filtered at -3dB per octave. So, it's "less harsh" sounding than white noise.


Since it's noise it's highly-random and that makes "exact" meter readings a little tricky. But, it's better than a test-tone because room-reflections can do "tricky things" with a single frequency that don't represent what's happening over the full frequency spectrum.



P.S.
Pink noise is also used for frequency response measurement. We are usually measuring (and equalizing) in octaves (or 1/3rd octaves, etc.). So for example, the octave from 200-400Hz is twice as "wide" (200Hz) as the 100-200Hz octave (100Hz). So with white noise (totally random) the wider 200-400Hz range contains twice as much energy.

3dB is a power (energy) factor of 2. So if we use a -3dB per octave pink noise filter, both bands will read the same and our instruments will "show flat" frequency response.

Last edited by DVDdoug; 06-04-2019 at 01:13 PM.
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Old 06-04-2019, 08:15 PM   #8
Baggage
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Originally Posted by DVDdoug View Post
But, usually there is no attenuation at maximum volume (in either channel) and the mismatch happens only at mid/lower levels. When you change the volume control the left/right balance changes and you can't fix that at the monitors.


It's a "shhhhhhh" noise that approximates the overall-average frequency spectrum of normal-everyday sound. You can find a sample to download or there are plug-ins that can generate it.


Technically, it's white noise low-pass filtered at -3dB per octave. So, it's "less harsh" sounding than white noise.


Since it's noise it's highly-random and that makes "exact" meter readings a little tricky. But, it's better than a test-tone because room-reflections can do "tricky things" with a single frequency that don't represent what's happening over the full frequency spectrum.



P.S.
Pink noise is also used for frequency response measurement. We are usually measuring (and equalizing) in octaves (or 1/3rd octaves, etc.). So for example, the octave from 200-400Hz is twice as "wide" (200Hz) as the 100-200Hz octave (100Hz). So with white noise (totally random) the wider 200-400Hz range contains twice as much energy.

3dB is a power (energy) factor of 2. So if we use a -3dB per octave pink noise filter, both bands will read the same and our instruments will "show flat" frequency response.
Very Educational and very much appreciated.
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