This guide will show you how set the default recording device and adjust the input volume to achieve the best sound when using any microphone (internal or external) in Microsoft Windows 7. If you are looking for directions for Windows 10, click here.

To get started, first right-click on the speaker icon in the task-bar next to the clock
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If you don't see the speaker icon, click the arrow to the left of the task-bar icons, You should find the speaker icon hiding out in there.
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In the pop up dialogue box, click Recording Devices
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This will open the Windows Sound Properties to the Recording Tab
In this screenshot the computer is showing me that I have both a USB Headset and a Microphone Array connected to the computer. The blue arrows are pointing to the device's hardware name, In this case C-Media USB Audio Device is my headset and High Definition Audio Device is my computer's built-in sound card. The default device the computer will use for all audio input is indicated by a green check mark. It's important to set the device you would like to use as the default so your software automatically chooses it as it's recording device. To do this:
Select the device you would like to use by clicking on it. If not already the default the Set Default button will un-grey itself. Click that and you'll see the green check mark switch to the device you selected.

There are a lot of different audio chipsets out there so you might see different device names. SoundMax HD, C-Media, IDT Audio, Texas Instruments, AC'97 Audio, Creative Labs, Conexant, Realtek, SigmaTel, Cirrus Logic these are just a few names you might see.
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Now that your default recording device has been selected and set. Let's adjust the levels to achieve optimum quality in your application
Click on your default device to select it, then click the Properties button.
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The Device Properties window will appear. Click the Levels Tab
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Using the controls you can adjust the input level of the microphone. Click Apply when you've set them so you can check how things sound in your application.
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Some audio devices also feature a Microphone Boost control. This is helpful for getting your microphone level up to normal operating levels and then can be fine tuned using the control above the Microphone Boost control. When you're satisfied with your settings. Click Ok to save.