Microphone boost on windows

Audacity 3 Help Forum Windows
1

Hello :slight_smile:

I have a question that has been bugging me for a while. I am using windows 8.1 and if i go under recording devices i have an option called microphone boost and it goes from 0dB to about 35dB. Now for the sake of an argument lets asume i am using microphone to record human speech and listen to it later, meaning i am not using a microphone to chat in real time (for instance Skype).

Now which one of the two would be true about this boost option. Will it:

a) be the same if i put microphone boost to 0dB and later use audacity to apply gain to make it sound louder (meaning is this boost basicly gain applied after the recording is already made and is only usable in real time chat where u dont have the time to apply boost after the recording is made )

or

b) does boost actualy make microphone record the sound better, for instance if there was a very silent noice, would it be possible that with 0dB boost the microphone would not record the sound (and no amount of audacity gain afterwards would help, u simply couldnt hear that sound), while on 35dB it would actualy record the sound ?

I hope you understand what i am asking. Thank you for your answer :slight_smile:

2

Microphone Boost is there because horrified manufacturers discovered nobody’s microphones would work right.

Everybody Knows you have to design quiet and slightly lower volume systems because you can usually make that up in post production. Having sound too loud causes data damage and is immediately fatal. So given those choices…

The problem comes when everybody does that “just to be safe.” That gives you the recording you can barely hear with all the adjustments cranked all the way up. I have a stand-alone USB microphone preamplifier that has never done anything useful because it’s just flat not loud enough.

This is where bottom-feeding kills you. There’s no way to tell ahead of time how they got the boost. If the natural design cuts down the volume by 20dB and the boost is really removing the cut, then the signal will be cleaner with less noise. What’s more normal is they throw an additional layer of boost and add that noise and distortion to what’s there.

Changing the gain of a microphone preamp is rough to do. Microphone signals have the power and energy of butterfly wings. The good amplifiers do a boost first with custom components and then turn the show over to downstream processing where they put the volume controls.

In general, unless they publish it, you will never know.

Koz

3

To give you an idea how microphone preamps work. I have a little Benringer UM2 stand-alone USB mic preamplifier. It says right on the tin it uses the same boost technology (XENYX Preamps) as on their larger mixers. The newer unit UMC22 uses the newer MIDAS preamps.

So it’s not a throw-away second thought like it is on soundcards. It’s the specific reason you cross the street with your checkbook and buy one over the other.

~~

There are tests you can do. Connect a microphone and make a recording at different settings. If everything increases volume with the boost, that is, the hiss, background sound and your voice all increase about the same amount, that’s probably the best you can hope for.

If the background noise increases faster than your voice and your voice quality or timbre starts to wander, then the boost was a stick-on, bad design they put in there to make it appear they were doing something useful.

It’s possible your voice will get louder without the background noise increasing. Nobody’s expecting that.

Koz

4

There is another evil possibility. Depending on your machine, you may only have one connection that they try to make do everything. Having a 0-35 slider is suspiciously close to switching between microphone input and 40dB attenuation so you can connect a hot, powerful stereo line device without causing serious overload.

Scene shifts to my little UM2. It has three separate input connections. Microphone, Instrument (guitar pickup) and Line. They do not subscribe to the fiction that you can make one connection slide gracefully between the three services.

5

Audacity can apply more gain than +35 dB, but your aim is to record so that the recording meters get up to about -6 dB for the loudest part of the recording. This gives you the best signal to noise ratio and a bit of leeway to apply any effects that may boost volume (boosting bass will boost volume).

Yes, generally speaking this should be less noisy than recording at too low a level then amplifying or normalizing in Audacity to compensate.


Gale

6

I will leave the boost at +0dB for now and do a gain and noise removal later.

I have another question. I tried 3 different computers (2 laptops and 1 desktop) with this microphone. On both laptops i am getting ground buzz as soon as i connect it to power suply (1 power suply has 2 pin cable - no ground, and the other one has 3 pin meaning it should remove this issue. ). But what boggles my mind is that i also get the same buzz on desktop computer, which is connected with 3 pin AC. I checked my power sockets and they do indeed have the side pins for ground. My question is as follows:

a) would using an usb preamp for mic similar to what kozikowski is using help solve this issue ?

b) would that in itself improve noise to usable sound ratio, or would i need to get a better mic for that ?

ps: i remember using noise removal years back and i had little to none success with it. I tried it again yesterday following a simple audacity guide i found online and the result was great, i just couldnt belive how great it worked. The noise on the recording was so high that certain words weren’t audible and after i did a noise removal i could actualy hear the voice alright.

7

i remember using noise removal years back

Forget those years. Noise Removal doesn’t exist any more. Audacity now has Noise Reduction. It’s still not intended to make a studio performance out of your banana peels and fish wrap, but it’s much better at current popular jobs such as reduce noise to get your voice performance quiet enough for AudioBook work without ACX being able to catch what you did.

I don’t know we ever found out what the microphone was. What is it? There is a very sharp divide between “computer” microphones and almost anything else (XLR type, sound support, rock band, broadcast, recording).

All these scenarios would be perfectly comfortable unplugging from one room, walking over and plugging into one of the others. Once you get into “pro” microphones, the standards tend to match and it’s all up to you to figure out how many you want use, how good they need to be, etc.

None of them will be plugging into a computer any time soon, and you won’t be plugging into one of their mixers or studio sound desks.

I need to read back through that again. One of the restrictions with computer microphones is they tend to have the shield/ground on the outside of the microphone. This can make hum problems come and go with how much you sweat.

Did you go through the room mains test?

Screen Shot 2016-06-06 at 3.51.25 PM.png
Screen Shot 2016-06-06 at 3.51.25 PM.png835Ă—443 159 KB

In all three houses I’ve lived in, at least one power outlet was wired incorrectly. Not kill you incorrectly, but the other one. The one where the protective shield and ground is actually connected to the neutral power pole across the street. Not recommended.

8

Thank you for all your replies !

Right now on 1 laptop i have +12dB boost and when no noise is made it will give me about -30dB in audacity. Does that feel ok or would you lower/raise boost ? I know it is best to test it and hear but just as a rule of thumb would you lower or raise.

As for testing grounds … i am dealing with a few dollar computer microphones here, i dont have that kind of fancy equipment to measure things, all i have is multimeter. I was wondering something. In case my wiring is really screwed, would connecting ground pin on laptop power suply to a grounded object, like heating radiator or kitchen sink do any difference ?

But this is really strange because i DO remember having the same mic plugged into my main computer and at first there was this buzz but then i think i moved the mic cord away from AC power and it was fine. Now no matter what i do it doesnt help. And my computer is different now, before i had sound blaster audigy 2 value for speakers and for mic, now i use usb DAC for speakers and use integrated soundcard for mic. Again, i am using same AC sockets in the wall as i did before and it worked fine before, while now, if i plug it in … bzzzzzzzzzzzzzzzzzzzzzzzzzz.

9

Oh, that’s just the invitation to war stories, isn’t it?

I have a musical bass cabinet that radiates a low level hum both sound and electrical—even when it’s off. It took months to find it.

It’s not shown in this illustration (for graphic simplicity), the sound mixer on the right plugs into the wall.

It has a"fat blob" power supply and I always assumed it fed clean, regulated battery voltage up the cable to run the mixer. It doesn’t. It feeds reduced voltage AC and it will hum if I get the microphone or the microphone cable too close.

Both of those are happening with good quality, recording configuration microphones and cables. “Computer microphones” are generally worse. The cables are poorer quality and they can’t be very long without picking up buzz and hum. The length restriction also means you can’t ever get away from a noisy computer.

You should probably know that grease and dirt are inconveniences with higher-end microphones systems, but they just kill computer microphones. The slightest finger grease on the microphone plug and there is no protective shield any more. Zero. Hum city. Did you touch the metal parts of the plug when you were installing the microphone? You probably shouldn’t do that.

I suspect the first thing I would do is clean everything with alcohol-based glass cleaner or unflavored vodka. Scrub the plug with fresh paper towels and plug and replug into the computer multiple times to insure a good connection. If you listen to the system while you do that (quietly), you may find the hum coming and going and sound crackling as you clean.

Koz

10

I did the cleaning thing, no luck. But things just got more interesting, 1 of the microphones is not buzzing anymore !

I got 2 microphones, 1 of them is connected with 5m long extension cord (3.5mm - 3.5mm) going into the other room (with no noicy computers and such things), the other one i am simply using for testing. And those microphones are pretty much the same, same 3.5mm jack, both got 2 wires into the mic itself, etc.

Now, the mic connected to 5m extension is the one buzzing when connected to main computer. It seems to be super sensitive to other electrical devices, but mostly if i put it near the laptop power suply it will start buzzing even when wire is a finger length away. What is funny is that with other microphone, i can touch the wire with microphone and it will make no difference. To sum it up, the microphone with extension has tiny hum even if laptop is on battery and is super sensitive to wires around it. Microphone without extension has no hum when laptop is on battery even if i put it right next to other devices.

One last thing. Microphone with extension … if i touch any part of laptop while recording, even plastic parts - it will start humming and buzzing. Microphone without extension i can touch any part of laptop and it will not hum or buzz even the slightest.

11

both got 2 wires into the mic itself, etc.

You shouldn’t go very far thinking that. Computer microphones have two interleaved connection systems…because it was cheap and inexpensive to do it that way. Taking the obvious one first, the voice signal comes down from the microphone on one of those thin wires and the shield. Needs both. If you lose either one, the voice drops dead.

This type of microphone takes a battery. Some microphones make you go out and buy an actual battery. You want to make sure you have spare batteries if you go out on a job. I’m not joking. This type of microphone works like that.

Computer microphones take a battery, too, but instead of making you go out and buy one, they borrow a little battery from the computer. That’s what’s going up the other thin wire and the shield.

Please note the shield is doing two different jobs at once. Second illustration in this page.

http://www.kozco.com/tech/audioconnectors/audioconnectors.html

If that last connection back becomes dirty, greasy or just broken or defective, you are seriously hosed. If it’s possible to change the cable between microphones, you may find that the hum follows one cable wherever it goes.

Koz

12

I just did some testing with different microphone and computers. I did as you suggested and plugged different microphone into an 3.5mm jack extension cord and i found out that the culprit was the microphone.
It is wierd though because that microphone used to work normaly and i checked and the only wires it was touching was internet lines (and just to test it i even unplugged them, didnt make a difference). The only time i could get it to stop buzzing is when i plug it into a laptop running on battery and even then you can hear a slight buzz. That microphone will simply have to be replaced.
As for other microphone, i found out that using 3.5mm jack extension makes no difference, at least not that i can hear, even though the extension is 5 meters long ! The only computer that it is buzzing when plugged is my small netbook that is using only 2 AC lines, meaning no ground. Kind of makes sense that it would buzz on that computer then. At least now i know other things are fine.

What is bothering me though is how bad are the recordings i am making with this microphones. Just for the fun of it i compared them to a simple recording i made with my cheap mobile phone and there is barely any noise on the recording, much less then with what i get on those pc microphones. I even recorded some college lab practices with my mobile phone so i could listen to it at home before exam and it was great. Since i dont intend to spend more then 10 dolars on a mic right now and those “skype pc” microphones seem to be that horribly bad, i was wondering if it wouldnt be better if i just bought the mic peace and connect the wire myself ? Maybe this way i can find a better part for this cheap price and then solder it to wires. If nothing else, at least i get to do something fun and learn something new, what do you think ? Ebay is full of those mic parts:

http://www.ebay.com/itm/10x-Dia-MIC-Capsule-Electret-Condenser-Microphones-For-MP3-Laptop-monitor-/191883383932?hash=item2cad24147c:g:LwIAAOSwwpdW9lav

13

i know other things are fine.

Right.

When the wizards fix this stuff it’s not magic (usually). It’s following lists of possible problems and make sure you don’t leaving anything out. Bow-ring.

I once followed a very highly respected techie around and in the back of my mind compared what he was doing with what I would have done. The only significant difference was he dotted every single “i” and crossed every single “t” with no exception. I would have left out steps in the job and thereby messed it up.

You can do a very good job with “home style” and computer microphones, but you can’t be sloppy and everything has to work perfectly correctly. The home stuff has no margin for error like the higher end stuff does.

how bad are the recordings i am making with this microphones.

They don’t have to be bad. I have a very old “home” Sony microphone that does a very respectable job. I bet I can create a voice track that you can’t tell from a better microphone.

Many home microphones suffer from Perception and Assumption. “Everybody knows home microphones sound crappy, so we don’t have to build ours very well.” Even worse, people make standard mediocre microphone parts and everybody makes their custom microphones from the same cheap parts.

simple recording i made with my cheap mobile phone and there is barely any noise on the recording,

There we have a special case. Those microphones are carefully matched to the phone and the expected environment. If those microphones fail, somebody will throw the phone against the wall, so those are self-limiting, however, you do have to be careful. Some of them are carefully tuned for voice and nothing else. They won’t do music at all. If yours does everything, then you got lucky.

[Shot on the iPhone 6s]

Because of the matching, you usually can’t bring the voice out and use it somewhere else in real time. If the job isn’t an APP in the phone, you lose. However, I know people who shoot sound on the Personal Recorder and match it up with the video later for a television production. You can do that. Don’t get stuck in one mind-set.

“I have to shoot it this one way or somebody will punish me.”

Maybe not.

Koz

14

Those microphone capsule are so cheap it would be a sin not to try and asemble 1 at home and then test against those cheap microphones i have. Maybe get different types of microphone capsules and compare them, it sounds like 1 of my projects that slows down my college progression !

If i were to buy for instance something like this:

http://www.conrad-electronic.co.uk/ce/en/product/710870/KEPO-KPCM-G97H67P-43dB-1188-microphone-capsule-22-k-15--97-mm-x-67-mm?ref=searchDetail
http://www.conrad-electronic.co.uk/ce/en/product/302104/200094-EMY-62NL101-Electret-Microphone-Capsule-Operating-voltage-1-10-Vdc-46-dB-Frequency-range-50-12-000-Hz?ref=searchDetail

I am looking for capsules that need no additional fancy stuff, except 3.5mm jack + wire ofcourse. What kind of characteristics would i be looking for to make sure my sound card and supply enough juice ? In my country for instance i saw capsules of 1, 2 and 4.5V DC. How would i know which one to pick and whether it will be ok ?

15

The electret to look for, is the Panasonic WM61a. It’s out of production, but stocks are still available. These are less than a dollar and very easy to use. You only need 3 to 9 V power supply and one capacitor to hook them up.

http://industrial.panasonic.com/cdbs/www-data/pdf/ABA5000/ABA5000CE22.pdf
https://pantherfile.uwm.edu/type/www/audio-reports/PanasonicWM-61A_OtherBinauralRigs/WM61A_Webpage_Caps_Mounts.html

These are suited for your first DIY mic. There are better capsules, fi from Transound or Primo, but these are hard to get and pricey. Around 20 times the price of the WM61a. And they require a lot more electronics, and a higher polarization voltage.

And watch out! Making mics is highly addictive to some… :nerd:

16

This looks great ! I am ordering this mic asap, and i have to check whether i have 1uF cap lying around or i have to order that aswell. On the second link you suplied i checked “Soldering cables onto WM-61A’s” and i didnt see the guy using any capacitors, does that mean using them is “optional”, serving purely as protection, or is it mandatory to use it ?

A quick question regarding voltage, mic is rated from 2V - 10V, does that mean suplying 10V will bring some improvement, like better sound to noise ratio, better sensivity, etc. ? Since i plan to use it with a computer it would be good to know how much voltage can a 3.5mm plug in sound card supply, couldnt really find a good answer to that question. But if more voltage equals to better sound, i can always use power from usb, which will give me 5V.