# In-built mic crackles



## rockinaway (Jun 24, 2006)

I record my music using the in-built mic in my MacBook. 

However, if the music gets even slightly louder then the mic can't seem to handle it and it begins to crackle and crack the sound up creating a poor recording. 

Is there any way of getting around this? Or do I have to buy a proper recording mic?

If I do need to buy a proper recording mic, what spec am I looking for and are there any special connections I need to connect it to a standard MacBook?

Thanks


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## sinclair_tm (Mar 11, 2005)

You need to get an external mic. The Mac's input won't work with any old mic either, which is a pain. The best thing is to find a USB mic that is Mac compatible.


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## rockinaway (Jun 24, 2006)

I do have a webcam with a mic built in. That is the best external one i have currently. So the crackling is just because it is the built in one?


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## sinclair_tm (Mar 11, 2005)

There is some kind of interference, hence the crackle. Make sure that there isn't any dust or stuff covering or blocking the mic.


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## rockinaway (Jun 24, 2006)

Oh.. it's only when my voice gets loud.. it seems to cut the sound out and crack it up. I assume either it's too much for the mic to handle?


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## jaythorpe522 (Sep 7, 2010)

Interference is not the problem (well, not the problem you're describing -- you could, I imagine, have that as well). You're hearing overmodulation distortion, which has a number of possible causes and a different fix for each cause.

First -- the sound is too loud for the microphone transducer to physically handle. With a condenser/capacitor microphone, the air pressure pushes the plates too close together and they arc. With a ribbon or moving coil microphone, the elastic potential is exceeded. These situations result in analog distortions with easily recognizable tonal characteristics (often desirous as music effects). Only solution -- make the source softer or move it away from the microphone.

Second -- the transducer (microphone) is outputting a signal that is too 'hot' for some part of the preamp stage before A/D conversion. Every source (microphone, instrument, playback device, etc) outputs at a slightly different level. While some may think it poor design for a built-in mic to be able to overmodulate the built-in pre's, the preamp stage for your MacBook may allow for higher gain for soft external mics, and as such the input gain needs to be dialed back for the built-in. This overmodulation results in a totally different sounding analog distortion. Best solution is to turn down your input gain. I'm not sure if you specified your OS, but this control will likely be found in something like: System Prefs > Sound > Input. Less-good solution is to make the source quieter/further away, but you sacrifice sound quality for noise by doing so.

Third -- the preamp may be overmodulating the A/D conversion circuit. Some may think it poor design for this to be possible, but it enables the preamp to be able to operate with the least amount of noise and heat, and most efficiency, if its max power is higher than the max possible input of the A/D. This overmodulation results in a very bad sounding digital distortion. The solution is the same as that for the 2nd condition.

Slow day at work today :grin:

TLDR: turn down your input gain: System Prefs > Sound > Input.

If you want to go with an external mic, tell me what kind of equipment you have already (any mixer, guitar amp, anything of the sort), what kind of music you're doing, and what kind of budget you'd put into this. I can make recommendations from $5k to $5 (if you're handy with a soldering iron and have a nearby RadioShack).

jw

[Edited because I misspelled 'quieter' -- oh em gee] [and again to add some commas to better offset a clause]


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## rockinaway (Jun 24, 2006)

Thank you so much for that detailed reply. I think your solution of turning down the gain may work. I will try that and see the result. I am currently running the latest version of Snow Leopard. 

As for external mic, well I currently have a webcam with in-built mic which I could use but I think that has some issues. I record basic vocals with an acoustic guitar at the moment so nothing too flashy. I have a standard MacBook. And I guess anything up to $100-$150 would be suitable. I live in the UK so I would prefer it to be locally available. 

Thanks


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## jaythorpe522 (Sep 7, 2010)

Blue Snowball. I think it's in that pricerange in the UK (just peeking at amazon.co.uk), it's cheaper in US.

If you're going to want to take it with you (i.e. hook it up to ANYTHING other than a computer or an iPad), then this mic isn't for you, it's USB only.

If you want a mic you can use for live/PA, then get a decent dynamic like something from the Sennheiser E-series or the good-old Shure SM57 or SM58, and an iMic to get it into your MacBook.

But that Snowball is fantastic for ease of use, versatility, and sound, as long as you will only want to use it with a computer.

The first mic from the Blue company was the Blue Ball. The handbook for it was hilarious. DaVinci and Beethoven endorsed the mic :grin: Inflate it to 25 PSI...


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## rockinaway (Jun 24, 2006)

Wow thank you! I also remember seeing a mic that MANY websites said is the best to start off with when recording at home. It was about $100 but I can't remember what it was now. 

Would you recommend not using the in-built mic at all?


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## sinclair_tm (Mar 11, 2005)

The built-in mic is great for web chatting, but that is about it. If you need to do recordings, you should get a mic for that.


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## rockinaway (Jun 24, 2006)

Okay thanks


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## jaythorpe522 (Sep 7, 2010)

rockinaway said:


> I also remember seeing a mic that MANY websites said is the best to start off with when recording at home.


They ain't no sich animal. The "best" mic to start off with when recording at home is different for everyone; it changes according to source, style, budget, recorder, future plans, location (size & type of room, type of background noise, even atmospheric conditions and the home's electrical wiring!), etc.

The classic PA workhorse is the Shure SM 57 and SM 58 (made exactly the same way, but the 58 has the 'vocal' windscreen). I wouldn't really recommend that for in-home recording, especially into a MacBook; it's a dynamic moving coil microphone and the low output level leaves a lot of audio stuck in the noise floor.

With a bigger budget, the mic I'd recommend for a starter would be a Sennheiser MD-421. It sounds wonderful on resonating string instruments (bowed, plucked, or hammered) and is great on mid-range voices (not soprano or basso profundo, but otherwise gets great tone and full harmonics). Best mic for dual use (live & studio) that I've heard (not as good on winds and brass, great on percussion). Solid as a rock, variable pickup sensitivity, $400 or so.

Even with a higher end dynamic mic like that, you'd still need an iMic (or something like it) to boost the gain in order to record into your MacBook. An electret condenser mic (has a battery-powered preamp) might or might not be hot enough to plug straight into the MacBook's jack without something in between. A true condenser mic needs a mic preamp that provides phantom power, so by definition it needs a box between the mic and the MacBook.

The Snowball sounds good, is designed for the exact situation you've put forth, and on top of that the company is good, which means the product should do its thing for as long as you can plug a USB cable into a computer. And it's within that price range (at least in the US, right at $100). But without a computer, it's a paperweight...

jw

PS -- were you able to adjust the input gain to a point where you were no longer distorting?


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## rockinaway (Jun 24, 2006)

Yeah that Shure one is the one I think I saw around the internet. This all makes a lot more sense to me now thank you. 

I did reduce the gain (you just mean input volume right? as that is the only thing I could change) and it helped a lot. I can sing more freely now and there is no distortion. 

I can tell the difference between the in-built mic and my external mic (even if it is fitted into a webcam). The external one has a certain clarity which the in-built doesn't; but i'm getting a constant buzzing which I assume is interference and that spoils it a little. I guess I will have to save up and buy the Snowball!


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