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[Sean Chen]

For some reason I am having difficulty with the mic preamp on the X32 and XAir mixers when I set the mic preamp to above +32 dB or more, the distortion and floor noise seems much more pronounced compared to +26 dB or lower. I am more experienced with Allen & Heath digital mixers where I have no problem using preamp gain up to +40 dB for a live mic signal. May I ask the Behringer X32 or X Air owners if you have come across similar issue?

[Robert Piascik]

Have not. I regularly set to +35

[Taylor Hall]

Does this happen regardless of the mixer's power source (ie different venues, different power conditioner/UPS/power distro rack)? Does it happen on all channels on the mixer? Is the signal going through a digital stagebox or direct analog to the mixer? Phantom power on/off? Ground lift? What steps were taken to make you think that it's the preamp?

[Sean Chen]

Does this happen regardless of the mixer's power source (ie different venues, different power conditioner/UPS/power distro rack)? Does it happen on all channels on the mixer? Is the signal going through a digital stagebox or direct analog to the mixer? Phantom power on/off? Ground lift? What steps were taken to make you think that it's the preamp?

I noticed the sound is more harsh with preamp set to +32 dB (PFL meter averaging +6 dB), so I turned it down to +26 dB (PFL metering averaging 0 dB) and pushed the speaker volume up, which made the harshness go away. Maybe there is clipping going on that is not registering on the meter. This leads me to think if there is sufficient usable headroom on the preamps.

My experience on Midas M32 does not have this impression.

[Lyle Williams]

Are you clipping somewhere else in the mixer?

[Lyle Williams]

If you are satisfied that you aren't clipping elsewhere (eg, you still hear it via PFL) then try this:

Solder a 200-ish ohm resistor between pins 2+3 in an XLR male plug.

Put that into the mic input on the mixer.  Still got noise?  Think preamp/mixer.  Noise is gone?  Think mic/cable/stuff thataway.

[Luke Geis]

My experience with the X32 et all is that they do not like running the HA hot or " cooked " as we call it. For most vocal mics I will end up around +17 or +20 and usually never higher than +24 for spoken word. On some instruments like keyboards, I will have to push the gain up over 30, but the incoming signal is low enough that there is no other way. I do not notice so much a distortion or change in sound ( and I have experiments that show there isn't any ), but I find that the operational characteristics change enough that you have to work outside of best standards and practices. I would guess that I have had to run an X32 up to +45 in maby half a dozen situations over the nearly 10 years I have been using them.

Some tests I have done with the X32 specifically about HA settings and its effect on mixer performance has shown that the HA is 100% linear and introduces no distortions until the red light is clipping. What goes in, comes out. What does change is the operational needs in order to deal with such hot HA settings. The aux sends are logarithmic just like a real pot and if you run the desk like you normally should with cooked HA settings, you will have excess noise and it is more prone to feedback due to the logarithmic nature of the pots fader. The self-noise of the HA is evident once you start getting past about +35 and after about +40 to +45 I find the self-noise to be very bad.

The X32 and X-Air line as far as I can tell really prefer to be run in the more textbook manner. I.E. setting the HA level so that the signal sets right around -18dbu on the meter. This usually means the HA setting will be right around +20 ish. I err to the cold side and try to have the peak of the signal just touching the -18dbu and find the X32 to be very clean, quiet and well performing when done as such.

[Kevin Bayersdorfer]

Both my XR-18 and my X32 I run around 25 for most vocalist and around 22 for a person with a set of pipes. Same for most everything else when micing a full band around 25 ish. Loud snare comes down to 21-22, hot active bass I have had as low as 16, ratty old P-bass as much as 30, but rarely.

[Sean Chen]

My experience with the X32 et all is that they do not like running the HA hot or " cooked " as we call it. For most vocal mics I will end up around +17 or +20 and usually never higher than +24 for spoken word. On some instruments like keyboards, I will have to push the gain up over 30, but the incoming signal is low enough that there is no other way. I do not notice so much a distortion or change in sound ( and I have experiments that show there isn't any ), but I find that the operational characteristics change enough that you have to work outside of best standards and practices. I would guess that I have had to run an X32 up to +45 in maby half a dozen situations over the nearly 10 years I have been using them.

Some tests I have done with the X32 specifically about HA settings and its effect on mixer performance has shown that the HA is 100% linear and introduces no distortions until the red light is clipping. What goes in, comes out. What does change is the operational needs in order to deal with such hot HA settings. The aux sends are logarithmic just like a real pot and if you run the desk like you normally should with cooked HA settings, you will have excess noise and it is more prone to feedback due to the logarithmic nature of the pots fader. The self-noise of the HA is evident once you start getting past about +35 and after about +40 to +45 I find the self-noise to be very bad.

The X32 and X-Air line as far as I can tell really prefer to be run in the more textbook manner. I.E. setting the HA level so that the signal sets right around -18dbu on the meter. This usually means the HA setting will be right around +20 ish. I err to the cold side and try to have the peak of the signal just touching the -18dbu and find the X32 to be very clean, quiet and well performing when done as such.

Thanks Luke for your insight.

To clarify my setup, it involve 2 totally different settings:

One is with the X-32 Rack for a live rock band gig at a bar. Mic is Beta SM86 for a male lead vocalist. At preamp gain of +26 I cannot bring him above the everything else in the mix, so I proceeded to up the pre gain to +32. I didn't notice the LED clip, but ouch it sounded harsh with the PRX pushing full volume. Maybe it's the combination of the mic, pre, and the speaker at that volume.

The other is with X-Air 12 for a Karaoke set up. Mic is wireless MiPro ACT-8 digital. With gain set to +32, there is artifacts that sounds like clipping, although it didn't appear so on the EQ page RTA. But after I reduce the gain to +26, the clipping went away with the average PFL level around + dB on the EQ page RTA. I was like, "Really"? I have to run this thing at 0 dB? Well, I had to turn up the speaker's input gain to get the volume back up, which increased the floor noise.

I've read there should be no discernible difference with modern day preamps. Or is there? If the Behringer X series mixers need to be run outside (colder) than typical gain structure practice, I would have difficult time spec'ing it in a system I put together.

[Kevin Maxwell]

Thanks Luke for your insight.

To clarify my setup, it involve 2 totally different settings:

One is with the X-32 Rack for a live rock band gig at a bar. Mic is Beta SM86 for a male lead vocalist. At preamp gain of +26 I cannot bring him above the everything else in the mix, so I proceeded to up the pre gain to +32. I didn't notice the LED clip, but ouch it sounded harsh with the PRX pushing full volume. Maybe it's the combination of the mic, pre, and the speaker at that volume.

The other is with X-Air 12 for a Karaoke set up. Mic is wireless MiPro ACT-8 digital. With gain set to +32, there is artifacts that sounds like clipping, although it didn't appear so on the EQ page RTA. But after I reduce the gain to +26, the clipping went away with the average PFL level around + dB on the EQ page RTA. I was like, "Really"? I have to run this thing at 0 dB? Well, I had to turn up the speaker's input gain to get the volume back up, which increased the floor noise.

I've read there should be no discernible difference with modern day preamps. Or is there? If the Behringer X series mixers need to be run outside (colder) than typical gain structure practice, I would have difficult time spec'ing it in a system I put together.

What output are you using on the mixer? And what is your routing to the output? Is there anything else in the signal chain? Have you looked at all of the pages under the meters button and looked to see if you can see anything clipping or looking weird? Can you upload your scene here or have you tried asking the same question on the Behringer forum? Have you tried moving the mic to a different input to see if it behaves the same way? I don't use the Behringer versions of these mixes much myself but I have never had the kind of problem on one that you are describing. Bu it sounds like you have a gain stage issue somewhere.

[ProSoundWeb Community]