Improving Your Audio: Hardware Edition

[ASIDE: Community Server (our current blogging engine here at CodeBetter.com) is swallowing the HTML5 <audio> tags in this post along with the Flash Player fallback. To hear HTML5 audio in your browser, jump to here with a browser that supports HTML5 audio such as FireFox 3.5+, Chrome, Safari, Opera, or IE9. I’ve successfully tested it in FireFox 4.0b2 and Chrome 6. I’ve also successfully tested it in IE8 where it falls back to the Flash Player. Sorry for the hassle.]

[ASIDE Part Deux: Brendan has tweaked the Community Server settings to allow CodeBetter to serve up <audio> tags. So the audio below should work now. Thanks, Brendan!]

Over the years, I’ve done a lot of audio work between podcasts, screencasts, and webcasts. So I know a thing or two about computer audio. I don’t claim to be an expert like my friends Carl Franklin or Richard Campbell, but I’ve done enough to be able to offer some helpful tips. We’re going to start with the hardware.

The quality of your computer audio can only be as good as the raw captured product. Use a bad microphone and no amount of software cleanup is going to magically produce good audio. You might be wondering how much difference the hardware can make? I’ve recorded the same audio track using four (4) different microphones on the same computer. (I didn’t record them simultaneously as multi-track recording is notoriously difficult, but I did say the same phrase into each microphone on after the other.) Let’s start with the LifeChat ZX-6000.

LifeChat ZX-6000

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My voice sounds like I’m on a telephone. The sound is hollow and lacks depth. If we plot a frequency analysis using Audacity, we can easily see the problems.

LifeChat ZX-6000 Frequency Spectrum

OK, maybe not easily if you’re not familiar with audio. Let me explain some basic ideas and then you should be able to see the problems.

Normal human hearing discerns frequencies between 20 Hz and 20 kHz. The standard tuning note for musicians is the 440 Hz, which is an A above middle C on the piano. The lowest note on the piano (A0) is 27.5 Hz and the highest note (C8) is 4186 Hz. (I’m using the example of a piano since many people, even non-musicians, have at least played with a piano at one time or another.) Lower frequencies correspond to lower notes and higher frequencies to higher notes. The frequencies mentioned are the fundamental frequencies. When you play an A4 on the piano (or any other instrument including the human voice), the major frequency is 440 Hz, but there are many harmonics or overtones that occur. These harmonics give a colour and depth to the sound. This is one of the reasons why different instruments sound vastly different when playing the same note – the harmonics produced by each instrument are quite different. This is how we perceive different ranges of audio frequencies. (Taken from Wikipedia Audio Frequency.)

Frequency (Hz) Octave Description
16 to 32 1st The human threshold of feeling, and the lowest pedal notes of a pipe organ.
32 to 512 2nd to 5th Rhythm frequencies, where the lower and upper bass notes lie.
512 to 2048 6th to 7th Defines human speech intelligibility, gives a horn-like or tinny quality to sound.
2048 to 8192 8th to 9th Gives presence to speech, where labial and fricative sounds lie.
8192 to 16384 10th Brilliance, the sounds of bells and the ringing of cymbals. In speech, the sound of the letter “S” (8000-11000 Hz)

Note how 2048 to 8192 Hz gives a presence to speech, whereas 8192 to 16384 give a brilliance. Without these frequencies present, speech will sound hollow.

With this in mind, let’s take another look at the frequency spectrum from the LifeChat ZX-6000. We see virtually no frequencies above 4000 Hz, which is making my voice sound hollow. Old analog telephones transmitted 200 Hz to 3000 Hz, which is why it sounds like I’m talking on an old phone. You’ll also note that the lower frequencies (below 400 Hz) are attenuated (e.g. not as pronounced), which is why the sound is lacking some of the bass timbre of my voice.

Let’s try a different microphone and see how it performs… Next up the LifeChat LX-3000.

LifeChat LX-3000

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The audio quality is vastly improved. Let’s take a look at the frequency spectrum.

LifeChat LX-3000 Frequency Spectrum

You can visibly see the difference. We have frequency response all the way up to 20 kHz with the majority of the response in the lower frequencies, which is expected due to the timbre of my voice. The lower frequencies are also not as attenuated. The quality of the sound is much warmer and vibrant with the LX-3000 than the ZX-6000.

As our last point of comparison, let’s listen to a semi-pro microphone – the one I use for my recording work – the audio-technica AT2020.

audio-technica AT2020

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The differences are subtler this time, but still noticeable. The audio has more depth and presence than with the LX-3000. Let’s take a look at the frequency spectrum.

audio-technica AT2020 Frequency Spectrum

Notice the better bass response below 400 Hz giving a truer rendering of my low voice. We also have better harmonics in the 10 to 20 kHz range, providing a more life-like sound. We can also take a look at the frequency response of the microphone, which can be found on the manufacturer’s website here.

audio-technica AT2020 Frequency Response

Note the flat response curve across the entire range of frequencies. This means that the microphone records all frequencies with equal efficiency, which results in little distortion of the raw sound. For comparison, I would expect the response curve for the ZX-6000 to drop to virtually zero above 4 kHz and show attenuation below 400 Hz. You want a flat response curve for your microphone as it will not colour or distort the recorded audio.

I should note that both the LifeChat LX-3000 and ZX-6000 have hardware noise cancellation. (Noise cancellation will remove an annoying background hum originating from fans, pumps, and other sources of low background noise. It can’t do anything to clean up dogs barking, children screaming, or other sudden noises that disrupt your recording sessions.) Applying software noise cancellation on either of these microphones has little additional benefit. The audio-technica AT2020 does not have hardware noise cancellation and benefits from applying software noise cancellation. Assuming you are working in a quiet environment the audio quality of the AT2020 without noise cancellation is still better than the LX-3000 and far superior with noise cancellation. Software noise cancellation usually involves little more than selecting a checkbox in programs like TechSmith Camtasia Studio or similar recording packages. You can perform noise removal using Audacity too, though it’s a bit more work as you have to manually select a quiet region with just the background noise that you want to subtract.

The LX-3000 is a great microphone for conference calls and gaming. It is a good, though not great, microphone for recording podcasts/screencasts/webcasts. It is inexpensive ($30 to $50), easy to use, and can be bought at most computer stores. If you’re just getting started, this is a good microphone to buy.

If you’re looking to take your audio to the next level, the audio-technica AT2020 is a great semi-pro microphone that you can pick up at reasonable cost. You’ll have to go to an audio specialty store as you won’t find these in your regular computer stores. I purchased mine at Long & McQuade, which is a chain of well-respected Canadian musical instrument stores. Now what is a reasonable cost? You’ll need more than just a microphone. You’ll also need a pre-amp to power the microphone as semi-pro and pro microphones don’t have high enough output to jack directly into your computer microphone port. You’ll need a pop filter (which prevents “p” and “t” sounds from making “popping” sounds in your audio), a mic stand, an XLR cable for mic to preamp, and a 1/4” to 1/4” male cable for preamp to computer (or 1/4” to 1/8” male if you are using a normal mic-in on your computer).

Component Price*
audio-technica AT2020 $120
ART TubeMP Tube Mic Preamp $49
Pop Filter $20
Mic Stand $20
2 Cables (XLR & 1/4”-1/4”) $20
Total $229

* Prices are in Canadian dollars.

You can get the same microphone (AT2020) with a USB option, but at a higher cost of $170, which is basically the cost of the preamp and cables. The TubeMP preamp has an actual vacuum tube that gives a warmth to the sound that is hard to achieve otherwise. Given the similar costs, I would personally err on the side of using a tube preamp over USB.

You might want to invest in a decent sound card, such as a Creative Labs X-Fi Platinum or similar card, which has better audio recording qualities than the audio-in that comes on your motherboard. It’s hard to find the X-Fi cards anymore. So you’ll have to look around to find a good quality audio card, but expect to spend $100 to $200 on the audio card alone. Remember your audio is going to be no better than the weakest link in the chain.

Is $229 of the audio-technica AT2020 worth the improved audio over the $30 to $50 LifeChat LX-3000? That’s up to you to decide.

About James Kovacs

James Kovacs is a Technical Evangelist for JetBrains. He is passionate in sharing his knowledge about OO, SOLID, TDD/BDD, testing, object-relational mapping, dependency injection, refactoring, continuous integration, and related techniques. He blogs on CodeBetter.com as well as his own blog, is a technical contributor for Pluralsight, writes articles for MSDN Magazine and CoDe Magazine, and is a frequent speaker at conferences and user groups. He is the creator of psake, a PowerShell-based build automation tool, intended to save developers from XML Hell. James is the Ruby Track Chair for DevTeach, one of Canada’s largest independent developer conferences. He received his Bachelors degree from the University of Toronto and his Masters degree from Harvard University.
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  • http://codebetter.com/members/james.kovacs/default.aspx james.kovacs

    @Matt – I’ve never used the Zoom H2. So I can’t comment specifically on the quality of that hardware. I do know that a good pre-amp makes a difference as I’ve mic’d my AT2020 directly into a USB mixing board. The sound is definitely flatter and not as warm as when going through the ART TubeMP. On the downside, you do have more gear and it’s less portable. If you’re going to spend a few hundred dollars on good recording gear, I would recommend going to somewhere like Long & McQuade with your laptop and try out their various mics and pre-amps in a sound booth to hear the difference.

  • http://www.impirus.com Matt Spradley

    Great post James. What do you think of the all-in-one recorders that also support USB and signal processing like the Zoom H2?

    http://www.zoom.co.jp/english/products/h2/

  • http://johannes.hansen.name/ Johannes Hansen

    Yeah, it also gets great reviews on various sites. It really seems as if this is the best semi-pro mic out there. The higher price in Denmark mostly comes from an hefty additional 25% sales tax, plus I bought another type of table stand which suited my need better but also cost a little more. But thanks again for leading me on the right trail James.

  • http://codebetter.com/members/james.kovacs/default.aspx james.kovacs

    @Johannes – Glad you found my post useful. The prices were meant to give folks a rough idea what quality audio gear will cost, as you understood. Honestly the AT2020 for ~$120 is a steal. Studio-quality mics often cost $800+ for the mic alone. Yes, the quality will likely be better than the semi-pro AT2020, but the improvement much less noticeable if at all. When I bought my AT2020 (on the recommendation of Carl Franklin), the tech at Long & McQuade commented, “That’s a great mic, especially for the price. You’ll get better quality audio than many of the more expensive mics.” The comment was completely unsolicited and gave me a good feeling that I was buying good gear. I hope your AT2020 serves you as well as mine has served me. Happy ‘casting!

  • http://johannes.hansen.name/ Johannes Hansen

    Thanks for the advice Jame, just went to the nearest danish music dealer webpage and ordered the AT2020 Mic + ART Tube MP + Pop Filter + Stand combo. Costa little more in Denmark, but everything does… So no biggie. I ended up spending about 300$ on the set.