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Microphone went dead after supper...

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Re: Microphone went dead after supper...

Postby CS70 » Sat Sep 15, 2018 8:54 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 9:10 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 9:31 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 9:40 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 9:52 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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Re: Microphone went dead after supper...

Postby audio_jungle » Sat Sep 15, 2018 10:01 pm

Watchmaker wrote: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.

My life is the 0.7%...

I was able to find two extra XLR cables, and have been very systematically trying different tests. For example, I got out my Electro-Voice mic and plugged one of the unused cables into it and then into my Onyx.

The signal is faint, but end result sounds okay.

Tried the other unused cable, and similar results.

Then I plugged my CloudLifter into one of the unused cables, and then ran the other unused cable to my Electro-Voice.

Tried recording with phantom power off and I got a flat-line.

Then I turned on the phantom power on my Onyx, and this is what I get...

First off, with GAIN = -15dB, and my PHONES set to 3 o'clock, I can now hear some slight static in the background, which I didn't get when my Electro-Voice was hooked up directly to my Onyx.

Next, if I turn GAIN = 10, I can hear static. If GAIN = 30, the static is at a normal (??) listening level. And if I turn GAIN = 35, then the static is loud as seen here...

Image


With GAIN = 30, if I record "Testing testing testing", I see this...

Image


When I listen to it, my voice sounds okay, but the static is almost as loud.

I have checked that the XLRs are firmly plugged into the CloudLifter. And I have already proven that both my regular and unused XLR cables are working fine.

The only thing I haven't yet tested, is this with my SM7B.

Maybe the CloudLifter isn't compatable with the Electro-Voice RE50N??

At any rate, it seems to me that my CloudLifter is toast...

And that really sucks, because without, I cannot record voiceovers with my SM7B, and even though it is unused, it is also 2 years old, so looks like I am out $150... :frown:
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Re: Microphone went dead after supper...

Postby audio_jungle » Sat Sep 15, 2018 10:15 pm

Just plugged in my SM7B and cranked GAIN = 40 with PHONES = 2 o'clock, and this is what I get...

Image


To get things to where my voice would sound normal, the static is load and obnoxious!!

Unless I am missing something else here, I think I have just proven that my (nearly brand new) CloudLifter just got fried...

Comments?

Suggestions?
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Re: Microphone went dead after supper...

Postby Sam Inglis » Sat Sep 15, 2018 10:18 pm

Yes that does sound as though the Cloudlifter might be faulty. (Could be worse, it could be the SM7...)

But do you really need it? Can you really not get sufficient input level by plugging the SM7 directly into the Onyx and turning the gain all the way up?
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Re: Microphone went dead after supper...

Postby James Perrett » Sat Sep 15, 2018 10:44 pm

I'm with Sam - you probably don't need the Cloudlifter. Don't be afraid to turn the gain up to 50 or 60dB - you'll probably hear a little hiss if you listen carefully but the results should still be usable.
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Re: Microphone went dead after supper...

Postby audio_jungle » Sat Sep 15, 2018 10:59 pm

James Perrett wrote:I'm with Sam - you probably don't need the Cloudlifter. Don't be afraid to turn the gain up to 50 or 60dB - you'll probably hear a little hiss if you listen carefully but the results should still be usable.

First off, based on what I said above, do you think my Cloudlifter is toast?

Or is my SM7B toast?


I just took the Cloudlifter out of the "chain", and did "Take 1,000,000".

It sounds okay, but I have to crank up the Gain to near max, and the signal is really weak.

BTW, when the Gain is cranked up, what exactly are you hearing?

Is that room noise or is it from your electronic components?


Here is what "Take 04" with my SM7B, hand-held, and no Cloudlifter looks like...

Image

It doesn't sound too bad for a newbie voiceover guy, but the signal is so wickedly low I am blow away!!

Can I even work with a signal that small?

(It doesn't help that I am still without a broadcast arm, which is why some more preamp would help!)
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Re: Microphone went dead after supper...

Postby James Perrett » Sun Sep 16, 2018 12:14 am

Can you post a short sound file somewhere so that we can hear it? It is hard to get an idea of the signal to noise from a picture. I'm also not totally sure whether it is the Cloudlifter or interface that is causing the problem from the description so far. Can you feed a line level signal to the interface and does it sound OK?
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Re: Microphone went dead after supper...

Postby audio_jungle » Sun Sep 16, 2018 12:36 am

James Perrett wrote:Can you post a short sound file somewhere so that we can hear it? It is hard to get an idea of the signal to noise from a picture.

If everything I bought wasn't broken, I would have had time to set up my webserver so I could do that?! :roll:

Can I use Imgur or something else that is free and doesn't require registration - as I have too many online accounts now!


James Perrett wrote:I'm also not totally sure whether it is the Cloudlifter or interface that is causing the problem from the description so far.

Can you feed a line level signal to the interface and does it sound OK?

What do you mean by that?

I have been trying to record some more voiceovers using just my Onyx and my SM7B without the Cloudlifter.

The recordings sound as good as they can being handheld, but the signal is wickedly weak.

That being said, I am pretty certain something happened to my Cloudlifter.

BTW, what would be a good solution moving forward as far as preamplification goes?

As mentioned before in other threads, I am in a hotel while I work out of state, so I try to keep my material possessions to a minimum.

Once I get better at voiceovers, I'll probably want to use my Ride NT2A condenser mic, so would I be better off getting a more professional audio interface/preamp? Maybe a mixer too? (And just ditch the Cloudlifter?)

I am actually ordering from B&H Photo tonight, so I welcome any recommendation fo where to go from here!

Or should I just buy a replacement Cloudlifter and see if the manufacturer will give me a refund of the (2-year old, yet still new) defective one?
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Re: Microphone went dead after supper...

Postby James Perrett » Sun Sep 16, 2018 1:00 am

audio_jungle wrote:
James Perrett wrote:Can you post a short sound file somewhere so that we can hear it? It is hard to get an idea of the signal to noise from a picture.

Can I use Imgur or something else that is free and doesn't require registration - as I have too many online accounts now!

How do you deliver your voiceovers to clients? I use Google Drive but others use Dropbox and similar services. You can also use WeTransfer for short term online storage (just send a file to yourself and then post the link they give in the confirmation email here). Soundcloud is also good for this sort of thing (and there are various Soundcloud alternatives popping up).

audio_jungle wrote:BTW, what would be a good solution moving forward as far as preamplification goes?

As mentioned before in other threads, I am in a hotel while I work out of state, so I try to keep my material possessions to a minimum.

Stick with the Mackie for now. If it is working it will be fine and I still think that you shouldn't need the Cloudlifter - especially if you can get fairly close to the mic. As I said before, don't be afraid to turn the gain up. Modern preamps bunch most of the gain up at the last few segments of the gain control knob (traditional older preamps have a pad button which means the gain control doesn't have to have such a wide range). I would expect you to be using the gain control at 3 o'clock or even higher - that's totally normal and not an indication that the interface doesn't have enough gain.

Resist the temptation to buy more gear until you gain more experience and have a better idea of what you really need. Acoustic treatment will be the biggest improvement for the sort of work you do and duvets strategically hung around you will make a huge difference.

Given your makeshift recording location, maybe you need to start choosing hotels based on the acoustic qualities of their duvets. :bouncy: :bouncy:
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Re: Microphone went dead after supper...

Postby audio_jungle » Sun Sep 16, 2018 1:12 am

James Perrett wrote:How do you deliver your voiceovers to clients? I use Google Drive but others use Dropbox and similar services. You can also use WeTransfer for short term online storage (just send a file to yourself and then post the link they give in the confirmation email here). Soundcloud is also good for this sort of thing (and there are various Soundcloud alternatives popping up).

I am starting a company offering many things including podcasts.

Since it is about provacy and security, I'm leery of posting my voice on a site where I would lose control - at least until I come out of my shell and (maybe) become famous.

Let me see if I can get a temporary webserver set up and post files there.


James Perrett wrote:Stick with the Mackie for now. If it is working it will be fine and I still think that you shouldn't need the Cloudlifter - especially if you can get fairly close to the mic. As I said before, don't be afraid to turn the gain up. Modern preamps bunch most of the gain up at the last few segments of the gain control knob (traditional older preamps have a pad button which means the gain control doesn't have to have such a wide range). I would expect you to be using the gain control at 3 o'clock or even higher - that's totally normal and not an indication that the interface doesn't have enough gain.

Without the Cloudlifter, I have been running the Gain around 4-5 o'clock. I turn it up until I hear hum, and then back it off until it goes away.


James Perrett wrote:Resist the temptation to buy more gear until you gain more experience and have a better idea of what you really need.

Good advice, but since I ultimately want to use my NT2A condenser mic, I will need more amplication that my Onyx puts out.

So should I buy a replacement Cloudlifter (US$150), or get a nicer audio interface/mixer/preamp?


James Perrett wrote:
James Perrett wrote:Acoustic treatment will be the biggest improvement for the sort of work you do and duvets strategically hung around you will make a huge difference.

Given your makeshift recording location, maybe you need to start choosing hotels based on the acoustic qualities of their duvets. :bouncy: :bouncy:

Ha ha. Yeah, I should probably get out my PortaBooth Plus that I bought. I just find it a PITA to set up, somewhat unstable on the mic stand I have, and the biggest setback is I have no practical way to read off of my lap or even a larger script because the PortaBooth is so small.

I will have to play around with treating my hotel room, once I get my audio gear working...

And once I can post some voiceover samples, I am sure everyone's feedback will help immensely!
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Re: Microphone went dead after supper...

Postby CS70 » Sun Sep 16, 2018 7:45 am

James Perrett wrote:
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).

Er, no? In technical terms power is the rate of energy itransfer per unit of time. It’s measured in watts, which is joules per second. Phantom “power” indicates the presence of a voltage differential - which is measured in volts. You can get power out if it, but it’s no power by itself.

The distinction is not particularly interesting for a mic user, which is why the loose usage is fine (and my comment). The OP seems to favor rather precise definition and that’s what physics is there for..
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