Low input Signal

[rosella84]

My equipment worked just fine during my last project, but suddenly the input is very low. I have tried recording piano with an aux cable and vocals with a condenser mic and an xlr cable, but both of them get very low input. The vocals can barely be heard before I put the gain on max on the Mbox mini.

I have tried to use the xlr cable and the mic with another mixer and it works fine, so I guess there must be a problem with the Mbox or ProTools First. Any ideas what can help?

[albee1952]

Is the phantom power turned on? Condenser mics require this and some interfaces will power up with phantom power turned off as a safety feature.

Saying you tried to record your piano with an aux cable makes no sense to me. Exactly what kind of piano? What outputs does the piano have? What is an "aux" cable?

[Darryl Ramm]

Oh boy giving clear info would help you here...

What exact model/generation mBox. If unsure link to a photo on the Web.

How are you determining the input is very low?

If you are looking at track meters and they are too low make sure you are in pre-fader metering mode. Sounds like you are listening to the output... but what are the track meter levels showing in dBFS when it seems too low?

If what you are hearing *while* tracking is too low but OK when you playback? If so then you are likely hardware monitoring through the interface, and need to turn up the monitor mix knob or adjust the monitor mix in the interface control software. Or maybe you don't mean to be using hardware monitoring and have accidentally checked "low latency monitoring" in Pro Tools.

Make sure the interface gain is turned up and the input pad is not engaged on the interface.

An acoustic piano or an electronic one? What exact make/model piano? If electronic what exact socket are you plugged into on the piano? If the piano is accoustic what exact make/model mic is connected to the cable and any cable/plug adapters used.

An aux cable? You mean an instrument cable aka cable with a 1/4" TR plug on both ends? or a cable with 1/4" TRS plug on one end?? going into the interface? what is on the other end? Use the proper names or if you are not sure find the cable online and give a link to it.

Describe exactly what socket/connector you are plugged into with what exact type of connector at each end of the cable. Be clear if using front panel or back panel connections on the interface.

One way to not get phantom power to the condenser mic is to short the phantom power on the other mic input. So unplug whatever cable is plugged into the other input and just see if you can get condenser mic working by itself on the mBox. And again make sure the gain knob on the mBox is turned up and the input pad is not engaged, if it still does not work check there is phantom power at the mic end of the cable with a multimeter.

[rosella84]

Okay, let me try to be clearer:
I have an MBox 3 Mini.
My piano is an electronic Yamaha Clavinova plugged into the Line/DI input at the back of the MBox with an 1/4" TRS plug at both ends.
My Behringer mic is plugged into the mic/line input.
Yes, of course I turn on the phantom power when I use the condenser mic.
I never have more than one instrument connected at the same time.
I don’t see anything about «low latency monitoring» in PT First.
I’m including a picture that shows you what I mean by low input. As you can see, the piano tracks have very low input in this project. Here the vocals looks like they have normal input, but that’s because I have turned the gain knob so far to the right that I also get a lot of white noise and bad quality.
PT.PNG

[Darryl Ramm]

It would help if you were very specific. e.g. What *exact* model Yamaha Clavinova, and what output are plugging into on the piano? Are you trying to use the AUX output or the headphone? We can't guess what you are actually doing...

... but beginner mistakes with stereo consumer devices like these digital pianos that output a stereo signal on a TRS connector would be to try to drive that signal into a balanced XLR input on an interface... are you using a TRS stereo to TS splitter cable (aka an "insert cable")? Otherwise you are driving a L+/R+ signal into a balanced TRS input the expects a balanced mono+/mono- and will hear a difference signal between each channel, or if the piano supports mono output who know what you'll get... but it might not be what you expect.. look in the manual. You likely should be spitting the TRS cable into two TR outputs using an "insert cable". Maybe using a DI box if there are grounding/hum issues. I would hope Yamaha provide information about connecting to balanced inputs.

The level of an audio signal on a waveform is hard to guess what that means. I deliberately asked for details like about dbFS signal levels on the input track... with the meter in pre-fader mode. There may be no harm (and some benefit) in tracking the mic at what some might consider quite low input (e.g. ~ -20dbFS).

I am guessing the Mic issue is seperate from the piano one, so try to answer every question for the mic. We cannot guess anything about what you are doing or your level of experience. e.g. are you sure the pad is not enabled (gain knobs are not pulled out)? And measure the phantom power voltage at the end of the cable if you can. What *exact* model mic is it?

Options>Low Latency Monitoring. You could google for that if you could not find it. Is it checked or not? Are you trying to use hardware monitoring from the interface or only through Pro Tools. You should be very clear on that.

[rosella84]

I have a Yamaha CLP-320. I have two headphone outputs which I plug into with a double 1/4" TRS plug at both ends.
The mic is a Behringer C-3.
The dbFS signal levels are around -30 for the piano and -35 for the vocals if I leave the gain knobs at 12 o’clock.
The gain knobs are not pulled out.
I can’t measure the phantom power, but the mic works at a mixing table, so I guess it should be alright.
«Low Latency Monitoring» does not appear under «options» to me. I read the help manual and it is not very likely that I have done all that by accident.
I’ve been recording with the same equipment for many years without having these problems. If these are two problems that suddenly appeared at the same time, I care most about solving the problem with the mic. That is the one that I can’t fix the volume of in the mix.

[Darryl Ramm]

Yey details.

Originally Posted by rosella84

I have a Yamaha CLP-320. I have two headphone outputs which I plug into with a double 1/4" TRS plug at both ends.

For the piano: Well there's your problem, as I suspected, you are plugging into a stereo TRS source and connecting that to a balanced mono TRS input. You can't do that. Pro Tools is going to be receiving the difference signal between the L and R channel which will be low and sound awful. You need an "insert" cable going from the headphone output to split to two TS plugs if you want to record stereo. And since you are using a headphone output you also will need to careful about gain staging with the headphone volume setting and the preamp/DI gain to see what sounds best overall.

If none of this makes sense grab a book on basic audio engineering, https://www.amazon.com/Recording-Eng.../dp/B01MY9ZP2W is a good one.

[Darryl Ramm]

Originally Posted by rosella84

I have a Yamaha CLP-320. I have two headphone outputs which I plug into with a double 1/4" TRS plug at both ends.
The mic is a Behringer C-3.
The dbFS signal levels are around -30 for the piano and -35 for the vocals if I leave the gain knobs at 12 o’clock.
The gain knobs are not pulled out.
I can’t measure the phantom power, but the mic works at a mixing table, so I guess it should be alright.

Test don't guess. You need to test the interface, cable, phantom power etc... see below.

I have no idea what is going on with Low Latency monitoring with the PTF UI. Like most folks here I can't and don't use Pro Tools First. It used to be in the UI. It's an important/handy option.

Are you sure the meters are in pre-fader mode... like when you move the fader up and down on the track the meter levels shown do *not* change?

If the meter levels really are low then it's not just a monitoring issue, but whatever is going on you should undetsand about hardware vs software monitoring and be clear what you are doing. The Mbox 3 Mini is simple there... you just make sure the Mix knob is turned all the way to the right/clockwise and you will get full software monitoring through Pro Tools, including hearing what Pro Tools is recording with an expected slight delay at larger IO buffer sizes. Turn it all the way to the left and you will only hear the input to the mBox through it's internal hardware mixer. You can test the microphone with the hardware mixer without Pro Tools running or connected. Just turn the mix knob all the way to the left/counterclockwise and talk into the mic while listening on headphones. Now try turning phantom power on or off and hearing how much of a difference it makes, same with pulling out the pad knob... see if they all work as expected.

The Mic cable you are using now has an XLR connector at both ends correct?

Make sure that Mic does not habe it's internal -10dB pad engaged.

Speak into the mic in as normal speaking voice. From a few inches away. See what levels you get.

I'm not familiar with that Mic... you might well have to turn the input gain up more than 12 o'clock, but not so much it sounds horrible.

If adding phantom power did not work at all or seem right and the mic still works with the mixer (ideally using the same cable) then you will need to find a multimeter and check the phantom power voltage at the Mic end of the cable. Also disconnect the cable and use the multimeter resistance/continuity mode to check the cable wiring is correct... pins 1, 2, and 3 are direct pass throughs. Any cheap digital multimeter is fine for this. Everybody working in audio should have one. But ideally a meter with true RMS reading is better for general use.

An additional tool you can use is the signal gen plugin on a track and output a sine wave at 1kHz out of one of your two output channels. Say run it at a very low signal level and use a balanced XLR to TRS cable to send it to the Mic input. And you should be able to lay around and measure the crude gain range of the mic preamp to check that lines up roughly with the specs.

[rosella84]

Under PTF Help it looks like Low Latency Monitoring should appear under «options». It doesn’t.
Yes, the meters are in pre-fader mood. The gain knob and the mix knob work.
Yes, my mic has an XLR connector at both ends. There is no sound when I turn off the phantom power. The internal -10dB pad is not engaged.
I’ve recorded with the mic at 12 o’clock. It was -30 db when I was close, and -45 a few inches away. I turned it up to 3 o’clock. There it was -20 close and -35 further away.
I’m going to borrow a multimeter this weekend.
I’ll look into the piano cables. Thanks! :)

[rosella84]

I checked the phantom power with a multimeter. Pin 1 and 2 showed 50.5 and the same for 1 and 3. Could it be a problem that there is too much phantom power?