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Microphone went dead after supper...

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Microphone went dead after supper...

Postby audio_jungle » Mon Sep 10, 2018 2:45 am

I have been playing around all day doing practice voiceovers.

Things have been going well, and I have recorded several project files in Audacity.

Before supper I unplugged my gear to clear off the table for supper, and when I hooked things back up to do a few more voiceovers before bedtime, my mic seems all but dead.

Now I am freaking out thinking I blew something up?! :cry:

I have a MacBook Pro, Sierra, Onyx Black, Cloud Lifter, Shure SM7B and Sony MDR-7506 headphones plugged into my Onyx.

TO MON is maxed out, and if I crank the GAIN to max and the PHONES to nearly max, I can bearly hear myself speaking into the Mic.

I have a virtual Lookback device setup with the "Audio Source" being my Onyx Blackjack.

One thing that seems strange, and I guess I never paid attention to what it was before is my Audio MIDI settings...

Here is the Onyx Blackjack...
Image

Image

Is that correct for those to be minimized and greyed out??


And here is my virtual Lookback device...
Image

Image


I sure hope I didn't blow up my microphone or audio interface or whatever?! :shock:
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Re: Microphone went dead after supper...

Postby Janneman » Mon Sep 10, 2018 5:53 am

Goodmorning,

DO see any input coming into the mackie black?

If so. Unplug everything, restart your computer and plug in the interface again.
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Re: Microphone went dead after supper...

Postby Sam Inglis » Mon Sep 10, 2018 6:43 am

Yes, it's normal for those settings to be greyed out on 'professional' audio devices like the Blackjack.

Have you checked that phantom power is enabled? The SM7 won't need it but I think the Cloudlifter does.
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Re: Microphone went dead after supper...

Postby Hugh Robjohns » Mon Sep 10, 2018 9:49 am

Don't panic! It's almost certainly a silly plugging error or incorrect setting. I think Sam could well be right about phantom power being switched off, but also check that you've plugged the Mic into the right channel -- it's easy to get them mixed up if you're leaning over from the front at.

Just work through calmly, checking everything in a logical progressive way. I'm sure you'll find the problem soon.
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Re: Microphone went dead after supper...

Postby Dave B » Mon Sep 10, 2018 11:25 am

Hugh Robjohns wrote:Just work through calmly, checking everything in a logical progressive way

But on this one occasion, you can skip the sparkly cape and 20 minute mellotron solo .... ;)
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Re: Microphone went dead after supper...

Postby audio_jungle » Mon Sep 10, 2018 6:05 pm

Janneman wrote:Goodmorning,

DO see any input coming into the mackie black?

If so. Unplug everything, restart your computer and plug in the interface again.

I have green lights for: Power, USB, and Phantom
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Re: Microphone went dead after supper...

Postby audio_jungle » Mon Sep 10, 2018 6:16 pm

Hugh Robjohns wrote:Don't panic! It's almost certainly a silly plugging error or incorrect setting. I think Sam could well be right about phantom power being switched off, but also check that you've plugged the Mic into the right channel -- it's easy to get them mixed up if you're leaning over from the front at.

Just work through calmly, checking everything in a logical progressive way. I'm sure you'll find the problem soon.

I think I have MAJOR problems...

Here is my current setup...

MacBook Pro => Onyx => CloudLifter => SM7B

Onyx Settings:
- Power on
- USB on
- Phontm on
- Gain (Channel 1): 1 o'clock
- Hi-Z filter off
- To Mon set at max (as usual)
- Phones set at 12 o'clock

Have my Sony MDR-7506's on, plugged into Onyx.

I hear steady static like a radio dial set to no station...

If I tap on the top of the mic with my finger I see the green light appear on Channel 1 signal indicator.

If I crank the Channel 1 Gain to 2 o'clock, the static is louder, and if I mouth the mic (like a rap star) and say "Test Test Test" I can barely hear my voice in the headphones, and there is a good chance that what I am hearing is my actual voice and not through the headphones...

I am starting to think I blew up my Shure SM7B, which is hard to fathom, considering that is a very rugged microphone!!
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Re: Microphone went dead after supper...

Postby Sam Inglis » Mon Sep 10, 2018 6:51 pm

It's possible the mic is faulty, but I think much more likely that you have a dodgy cable. Also, try plugging the mic in without using the Cloudlifter -- you'll need to turn the gain up to maximum but you should be able to get a clear signal.
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Re: Microphone went dead after supper...

Postby audio_jungle » Mon Sep 10, 2018 7:04 pm

Sam Inglis wrote:It's possible the mic is faulty, but I think much more likely that you have a dodgy cable. Also, try plugging the mic in without using the Cloudlifter -- you'll need to turn the gain up to maximum but you should be able to get a clear signal.

Working backwards...

Could I blow up an SM7B with too much power?

For example, if having both the Onyx'x Phantom power on PLUS the CloudLifter too much power?

What about if I plugged in another microphone? Could that happen as well?

These cables probably have less than 20 hours on them... Could they break that easy?

What about what I mentioned in my OP about the levels in the Audio MIDI Setup not looking right?

If things are minimized out, then maybe that forces me to crank up the Gain on the Onyx, and so it is like trying to suck water out of a straw?
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Re: Microphone went dead after supper...

Postby Watchmaker » Mon Sep 10, 2018 7:39 pm

Dave B wrote:But on this one occasion, you can skip the sparkly cape and 20 minute mellotron solo .... ;)

:clap:

Working backwards:

Everything was set up and working fine. You then folded up, had dinner and set it back up. it's fubar.

99.3% chance of operator error. Tear it down, have a beer. calmly set it back up.
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Re: Microphone went dead after supper...

Postby Sam Inglis » Mon Sep 10, 2018 7:39 pm

I think you're confusing power with gain here. The only source of power involved is the +48V phantom supply from the Onyx, which drives a small fixed-gain preamp inside the Cloudlifter. Changing the gain setting on the Onyx makes no difference to the phantom power.

The only way to find out what's broken is by swapping out different parts of the signal chain. The easiest places to start are by swapping out the cables and removing the Cloudlifter from the chain as previously suggested.
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Re: Microphone went dead after supper...

Postby ConcertinaChap » Tue Sep 11, 2018 10:57 am

audio_jungle wrote:[What about what I mentioned in my OP about the levels in the Audio MIDI Setup not looking right?

It may not look right but it really is OK. Here's mine, for comparison.

Image

Image

I'm afraid the others are right, you're just going to have to swap stuff around until it starts working again. Only change one thing at a time, though.

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Re: Microphone went dead after supper...

Postby audio_jungle » Sat Sep 15, 2018 3:53 pm

Week from HELL from work last week... :roll:

Finally getting back to my aduio gear this morning.

I found two un-unsed XLR cables, so will take the advice above, and *pray* that it is something dumb, and not a technical issue, as I really want to get my IVR done!

Stay tuned...
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Re: Microphone went dead after supper...

Postby audio_jungle » Sat Sep 15, 2018 4:14 pm

Sam Inglis wrote:I think you're confusing power with gain here.

The only source of power involved is the +48V phantom supply from the Onyx, which drives a small fixed-gain preamp inside the Cloudlifter. Changing the gain setting on the Onyx makes no difference to the phantom power.

Not sure that I follow you...

My understanding is that certain microphones - usually condenser mics - require more power than a conventional dynamic mic, right?

So "phantom power" is that extra voltage, right?

What is confusing me, is that I thought the CloudLifter somehow provided extra power too? (I'm not an electrical engineer, so not sure how all of that works, but I thought the CloudLifter somehow stored up the power coming out of your audio interface and gave you extra power as well?)


Can you extra some more what what is the difference between extra power and what a "preamp" and "amplification" in general does/means?



Sam Inglis wrote:The only way to find out what's broken is by swapping out different parts of the signal chain. The easiest places to start are by swapping out the cables and removing the Cloudlifter from the chain as previously suggested.

If I plug a non-condenser microphone into my Onyx, and turn on the Phontom power, will that ruin something like my Shure SM7B mic or my field reporter Electro-Voice RE50N/D-L mic?
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Re: Microphone went dead after supper...

Postby Sam Inglis » Sat Sep 15, 2018 7:33 pm

A microphone converts acoustic energy into electrical energy, outputting a very low-amplitude signal. This needs to be pre-amplified before it reaches the analogue-to-digital converter and is transformed into a stream of numbers that your computer can record. This pre-amplification is done using active circuitry which requires power to operate. That power can come from a mains supply, from USB bus power or even from batteries.

Some mics require more pre-amplification than others, which is why preamps have a Gain control. A few mics require so much pre-amplification that the preamp in an interface such as the Onyx might struggle to deliver enough gain. But this has nothing to do with electrical power, it's just that those mics (the SM7B is one) lie outside the range the designers of the audio interface were anticipating.

Some microphones also have active circuitry in them which requires power to operate. This includes all capacitor (condenser) mics. Nearly all of these mics are designed to draw that power from your mixer/audio interface through a 48V phantom power supply. The amount of power the mic draws is minimal -- usually much less than 1 Watt -- and is always the same.

Other mics, including the SM7B, are completely passive devices, meaning they draw no electrical power at all.

Moving the Gain control on your preamp doesn't significantly vary the amount of electrical power drawn either by the mic or the preamp, and in any case, the amount of power needed is relatively small.

Essentially, you could think of the Cloudlifter as a device that turns a passive mic (such as the SM7B) into an active mic, delivering a stronger signal so that the interface preamp does not need to apply so much gain. It too is an active device that takes its power from the phantom supply. It applies a fixed amount of gain and its power draw should be the same regardless of how loud or quiet the signal is.

Phantom power is designed to be 'invisible' to passive circuits, so there is no possibility of damaging your SM7B by accidentally applying phantom power to it. But the SM7B doesn't benefit from phantom power or need it in any way.
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Re: Microphone went dead after supper...

Postby CS70 » Sat Sep 15, 2018 7:54 pm

audio_jungle wrote:Can you extra some more what what is the difference between extra power and what a "preamp" and "amplification" in general does/means?


A dynamic mic produces a signal without any external power. A condenser need phantom power to produce a signal. With this latter one, no phantom power, no joy - nothing happens.

In both cases that signal is very, very weak. It needs to be amplified to a level where the downstream components can work on it. That’s the (preamplifier) “gain”. It’s a knob since not all dynamic and condensers mic are created equal and different mics, regardless of condenser or dynamic, will put out slightly different (weak) levels, so your gain knob allows your preamplifier to work well with a wide range of mic of any class.

Once preamplified, the signal is strong enough that an EQ, a compressor or any of the million effects you can torture it with, work fine. Note that it’s still not strong enough to drive a loudspeaker - another amplifier (the “power amplifier”j has that job, and that also has its gain knob.. which is usually called “volume” :)
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Re: Microphone went dead after supper...

Postby CS70 » Sat Sep 15, 2018 8:10 pm

Crossposted with Sam.

One more thing that may help: it’s called “phantom power” but it’s not “power” in the technical sense - it’s a voltage difference, of around 48V. It’s called “power” just because without it condenser mics do nothing, so it’s an intuitive term for people who just want to get on with it
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Re: Microphone went dead after supper...

Postby audio_jungle » Sat Sep 15, 2018 8:31 pm

Sam Inglis wrote:A microphone converts acoustic energy into electrical energy, outputting a very low-amplitude signal. This needs to be pre-amplified before it reaches the analogue-to-digital converter and is transformed into a stream of numbers that your computer can record.

And where is that converter?


Sam Inglis wrote:This pre-amplification is done using active circuitry which requires power to operate. That power can come from a mains supply, from USB bus power or even from batteries.

Some mics require more pre-amplification than others, which is why preamps have a Gain control.

I have an audio interface...


Sam Inglis wrote:A few mics require so much pre-amplification that the preamp in an interface such as the Onyx might struggle to deliver enough gain. But this has nothing to do with electrical power, it's just that those mics (the SM7B is one) lie outside the range the designers of the audio interface were anticipating.

Am I doing myself a disservice starting off with an Onyx Blackjack? (I bought it becasue it is small or thus portable when I travel.)


Sam Inglis wrote:Some microphones also have active circuitry in them which requires power to operate. This includes all capacitor (condenser) mics.

Nearly all of these mics are designed to draw that power from your mixer/audio interface through a 48V phantom power supply. The amount of power the mic draws is minimal -- usually much less than 1 Watt -- and is always the same.

Other mics, including the SM7B, are completely passive devices, meaning they draw no electrical power at all.

So my Electro-Voice RE50N and Shure SM7B are passive mics?

And my Rode NT2A is an active mic?

And there, only the Rode requires phantom power?


Sam Inglis wrote:Moving the Gain control on your preamp doesn't significantly vary the amount of electrical power drawn either by the mic or the preamp, and in any case, the amount of power needed is relatively small.

Essentially, you could think of the Cloudlifter as a device that turns a passive mic (such as the SM7B) into an active mic, delivering a stronger signal so that the interface preamp does not need to apply so much gain.

So the CloudLifter is a preamp?

And if so, the Cloudlifter adds additional signal preamplification on top of the preamp in my audio interface?

Or does my audio interface not have a preamp?


Sam Inglis wrote:It too is an active device that takes its power from the phantom supply. It applies a fixed amount of gain and its power draw should be the same regardless of how loud or quiet the signal is.

So one or more of the pins/wires going into the ClodLifter is a power supply and needed to make it work?

If so, if I turn off the Phantom power switch on my Onyx, then the CloudLifter stops preamplification, because it has no power to work?


Sam Inglis wrote:Phantom power is designed to be 'invisible' to passive circuits, so there is not possibility of damaging your SM7B by accidentally applying phantom power to it.

I thought I heard that some type of microphones (maybe "ribbon" mics) can be destroyed if you turn on the Phantom power while using them?


Sam Inglis wrote:But the SM7B doesn't benefit from phantom power or need it in any way.

But the CloudLifter needs Phantom power to run and deliver more preamp that the SM7B *does* need, right?
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Re: Microphone went dead after supper...

Postby James Perrett » Sat Sep 15, 2018 8:40 pm

CS70 wrote:Crossposted with Sam.

One more thing that may help: it’s called “phantom power” but it’s not “power” in the technical sense

Erm - phantom power IS power but just not very much as the current is limited to 14mA (7mA in each leg). The maximum power that could be delivered to a mic would be just under 170mW although most condenser mics should require less.

I was wondering whether you might be confusing this with the polarising voltage needed by standard condenser capsules? This requires virtually no current but it also requires the use of a preamp with a very high input impedance placed close to the microphone capsule. This preamp will require a certain amount of current (and therefore power).
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Re: Microphone went dead after supper...

Postby James Perrett » Sat Sep 15, 2018 8:52 pm

audio_jungle wrote:
Sam Inglis wrote:A few mics require so much pre-amplification that the preamp in an interface such as the Onyx might struggle to deliver enough gain. But this has nothing to do with electrical power, it's just that those mics (the SM7B is one) lie outside the range the designers of the audio interface were anticipating.

Am I doing myself a disservice starting off with an Onyx Blackjack? (I bought it becasue it is small or thus portable when I travel.)

Just had a quick look at the specs and they seem reasonable - certainly better than similar alternatives but not quite up to the highest standards.

audio_jungle wrote:

So my Electro-Voice RE50N and Shure SM7B are passive mics?

And my Rode NT2A is an active mic?

And there, only the Rode requires phantom power?

Yes - that's right.

audio_jungle wrote:So the CloudLifter is a preamp?

And if so, the Cloudlifter adds additional signal preamplification on top of the preamp in my audio interface?

Or does my audio interface not have a preamp?

Your audio interface has a pretty well specified preamp and you may well get away without the additional gain from the Cloudlifter.

audio_jungle wrote:I thought I heard that some type of microphones (maybe "ribbon" mics) can be destroyed if you turn on the Phantom power while using them?

There were one or two in the old days that used centre tapped transformers which could be damaged by phantom power but any modern mic with any pretensions to being professional should have no problems with phantom power. If they are designed in such a way that they would be damaged then they have no business being called professional mics.
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