Simple Ways to Use Your Microphone’s Bass Roll-off and Pad Switch

I got this quick question about recording mics:

I own a CAD GXL3000 mic and I was wondering at what instances would you use the roll-off feature and the -10dB pad switch. Thanks

What a great question. Although it might be a fairly basic question, it’s never too late to understand the simple basics behind recording.

Using the Bass Roll-Off

Depending on the microphone, the bass roll-off frequency will be different. It’s common to see the roll-off be at 80 or 100 Hz.

The roll-off has a few different uses.

• Removing low-end rumble and hum – A home studio has a lot of different things making noise: A/C, neighbors, cars driving by etc. Not all of these noises can be removed by simply flipping this switch, but it can help reduce the low end hum from being recorded.
  
• Controlling the proximity effect – The closer you get to the microphone, the bigger the bass response. By cutting the low-end you can fight unwanted low-end coming from the vocals. Of course, this is a preventive measure if your singer gets a little too up close and personal.
• As a substitute for a filter – There are different opinions on this but if you’re planning on filtering out the low-end anyway during mixing, you might as well filter it out from the start. Then, if you need to filter more you can do so later but at least you don’t end up with unnecessary low-end frequencies in your mix.

Padding the Gain

The pad helps you get an accurate signal from loud instruments. Say you have a kick drum that overloads your channel even though the interface gain is all the way down.

By switching on the pad you lower the gain from the microphone by -10 dB, giving you more “gain-room” to record that loud kick drum. The microphone essentially reduces the amount of volume allowed into your interface.

I recommend using the pad as a last resort. Don’t add unnecessary gain changes to your signal flow unless it’s absolutely necessary.

Simple Yet Easily Forgotten

These basics are often overlooked and not even thought about. That said, they are important for any audio engineer to know. The roll-off has a few simple functions and the pad can be crucial for recording that incredibly loud instrument.

If you want more easy to understand information on everything you need to learn how to record and mix, check out Recording & Mixing Strategies:

www.audio-issues.com/strategies

Image credit: http://www.flickr.com/photos/zoomar/2265202595/sizes/z/in/photostream/