What is Frequency Response?
If you have been spending much time learning about creating your own home studio to record music you have probably come across the term “Frequency Response”. But what is frequency response and how does it apply to you? What do people mean when they say they want the flattest frequency response speakers, headphones, or microphones? Is it really that important?
Yes, know what frequency response is and how it affects your recording is very important. If you just dive in and start reading all the technical aspects it can be a little intimidating. You don’t have to be a scientist to understand the important parts, and I think I can explain it in a way that should be easy to understand.
Frequency Response Definition
The quick and confusing definition of frequency response is: “The dependence on signal frequency of the output–input ratio of an amplifier or other device.”
My (hopefully) less confusing definition is: “The measurement of how well a speaker or microphone reproduces sound in the range of human hearing”
If you are a human, and I suspect you might be, then you can hear frequencies in the range of 20Hz all the way up to 20kHz. These are the ranges of frequency that frequency response is, for the most part, measured in.
Frequency response measurements are typically given to you in a chart. Below is the frequency response chart of the Shure SM57 Microphone. The dark line on the chart shows you how far from a flat response (The 0 horizontal line) the output deviates.
Still not sure exactly what people mean when they are talking about frequency response? Here’s a different type of example:
It’s Thanksgiving and I’m in the living room hanging out with my brother-in-law Frank while we’re waiting for dinner. I tell him a long story about the time I went to the grocery store to get some pizza rolls that were on sale. While I was there I also got some bananas, ran into an old friend of mine who was having a baby, tripped over my untied shoelaces and smashed the cantaloupe I was carrying, saw an old man get mugged, dropped my car keys, and then ended up forgetting to get the damn pizza rolls.
My story was the “frequency” that I was “inputting” into Frank. Later on in the day when Frank tells (outputs) the story(frequency) to my uncle it will probably differ in places. Frank might start the story the same way with the pizza rolls, but leave out or barely mention the bananas I got and the old friend I saw. He will also probably really emphasize the part about me tripping and smashing the cantaloupe and about the old man getting mugged.
The differences between the story I tell Frank and the story Frank tells my uncle is the frequency response.
Hopefully that story helped some of you. If not, well I still had fun typing it.
What is Speaker Frequency Response?
Most speaker are designed to play sounds (music, voices, etc…) in the frequency ranges that humans car hear (duh). Frequency response is the measurement of how different the frequency that you put in to the speaker is from the frequency that you hear coming out of the speaker.
The flatter the frequency response of your speakers, the more accurate the sound out of the speakers will be. It is very important to have the flattest frequency response monitor speakers that you can when mixing. You need to be sure that what you are hearing out of your speakers is as close to the real frequency as possible. If your speakers are unable to reproduce high or low end frequencies, then you will be unable to accurately mix music and you will have an inferior product.
Below is the frequency response chart for the Yamaha HS8 Studio Monitors. As you can see the response is extremely flat between about 40Hz and 30kHz. This means that they will output a very accurate sound across almost the entire range that humans can hear (and actually far past the high end). The Yamaha HS8 studio monitors are very good quality speakers, and give some of the flattest frequency responses for affordable monitors.
Here is the frequency response chart for the KRK Rokit 5 G3 Monitors. You will notice that the line doesn’t get to the 0.0 line until almost 100Hz. This means that it will not accurately play low end frequencies. If you are mixing violin music this may not be a problem This is not the best studio monitor for mixing EDM music though. If you drop the beat on these, you might lose it. (I crack myself up).
What is Headphone Frequency Response?
The frequency response for headphones is the same as for speakers or studio monitors. They are just speakers you put right next to your ears after all.
Take a look at the frequency response chart for one of the most widely used headphones in a home studio; the Sennheiser HD 280 Pro:
This is why you should do your mixing with monitors and not headphones. As you can see above the headphones only give a flat response between about 100Hz and maybe~1000Hz. Anything you hear outside of those frequencies is simply not an accurate representation of the original sound.
That’s not to say that you can’t buy headphones that have a better frequency response. You can. The best flat response headphones that I have used are the Audio Technica M70X headphones. I have occasionally done some mixing with these, but I still double check with my monitors from time to time. Flat frequency response headphones also cost a bit more.
In general, you should use studio monitors to mix. There are many reasons for this that I won’t go into right now. If you want to learn more about this then check out this article I wrote.
What is Microphone Frequency Response?
Microphones are, of course, designed to capture frequencies that humans can hear (singing, talking, instruments, etc…) and then record them. The frequency response of a microphone is the measurement of how close the recorded frequency is to the original sound (frequency) your guitar (for example) made.
Microphones are a bit different though because you don’t neccasarily always want a perfectly flat frequency response. Many microphones are designed to highlight or play down certain frequencies. For instance the Shure SM57 and Sm 7B microphones are designed differently from each other to either enhance vocal pickups, or to better record different instruments.
Hopefully I answer the question “What is Frequency Response” sufficiently above. It is an important factor when buying studio equipment. You don’t want to spend big money and end up with equipment that will not allow you to produce professional music.
Disagree with anything I wrote? Let me know below!