A Word About USB Audio Hardware

I have had some issues dealing with “experts” at local music stores and even reviews of products online; in particular dealing with USB condenser microphones used for music recording. I though that since I could see how so many people claim to be experts, yet give misleading information, I should do my part is dispelling some myths about USB audio hardware using a particular example.

Even some “experts” at the music store will have no clue what they are talking about, so let me enlighten you something so you won’t fall prey to their stupidity.

I like to record music from time to time on my computer.  Nothing special, a riff here or there on the guitar, or a cover song or something. I wanted to have the simplest method for recording so when I chose to, I can focus on recording music instead of setting things up.   I found the MXL USB.006 Condenser Microphone to be perfect for my application, however everyone and their brother advised me against it. Even the guy who sold it to me at “Guitar Place” said it wasn’t as good as running a standard condenser mic through a mixer and using a USB sound card. The one he recommended was the Behringer UCA202.  So I bought them both to see the differences.

With both items plugged in, issuing the command “lsusb” to list all my USB devices in the terminal shows the following:

Bus 008 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 007 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 006 Device 004: ID 08bb:2900 Texas Instruments Japan PCM2900 Audio Codec
Bus 006 Device 003: ID 08bb:2902 Texas Instruments Japan
Bus 006 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 005 Device 007: ID 062a:0000 Creative Labs Optical mouse
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 003: ID 1267:0103 Logic3 / SpectraVideo plc G-720 Keyboard
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

The numbers in the 6th column show the hexadecimal of values vendor ID and product ID numbers.  You can see two entries for “Texas Instruments…”  The one that says “PCM2900 Audio Codec”  is the MXL mic.  The other TI entry is for the Behringer UCA202.   Notice that the Product ID is very similar (2900 vs. 2902).  This refers to the chip they are using to convert the audio to USB.  Being that they are both 290x means they are the same series of chip.

Here are the datasheets for these chips:

Here’s the 2902 (in the Behringer) and here you can find the 2900 (in the MXL mic)

The only difference between these two chips is that one (the one in the Behringer) has SPDIF out, and the other does not. Quality is exactly the same.

This lead me to think that the foretold lack of quality must be from an inferior microphone element. This lead me to more research. The mic itself is considered a “cardioid condenser mic.”  “Cardioid” means if you were to draw out a shape of where the mic can actually pic up sound (its sensitivity pattern) you will find it is shaped somewhat like a heart ( ♥ ). Wikipedia has a great article showing the different sensitivity patterns of mics.

The term “condenser” means that basically the mic is a variable capacitor. Sound waves vary the distance between two capacitive plates changing the capacitance between them. This change in capacitance is the electronic incarnation of the sound, allowing it to then be mixed normally.

MXL claim that they use their standard gold-sputtered diaphragm condenser mic element in the USB.006.

Condenser mics require DC power to work . For this they use 48v Phantom Power. This is basically provided by a mixer or preamp and is sent via XLR mic cable. Since the USB.006 mic has no normal XLR cable, they MXL had to come up with a way to provide phantom power for the mic element. They likely used a charge pump circuit to up the 5v DC USB power to 48v. This allows the output of the MXL USB.006 to be exactly comparable to standard condenser mics.

It is safe to say that the MXL USB006 mic has the same quality as any comparable mic running through a mixer and into the Behringer UCA202. Anyone who says they can tell a difference is a complete moron (like many self proclaimed “gurus” who work at music stores.)  Put it this way; if they knew what they were talking about, do you think they’d be the guy selling you stuff at the music store?

I know this isn’t the case for everyone. Many times you will find an authentic guru at the music store.  It just really bothered me how these people just accepted that the USB mic wasn’t as good as the other methods because some other “expert” told them so. Worse than that, they undersold themselves (sicne many work on commission and the Behringer costs about 1/3 to 1/4 the costs of the USB.006 mic) and perpetrating a lie. Spouting off bad advice is no way to help people. If you don’t know what you are talking about, please at least try to look it up before giving advice on the topic.

Both the MXL USB.006 and the Behringer UCA202 are great cheap USB sound devices and I highly recommend both of them to anyone looking for good quality simple and fast recording. Personally, I use them both at the same time when I record, and even use the Behringer UCA202 as the default sound card on my machine.

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