Tag Archives: Equalizer

Emulate an ATM-311 on MacOS X

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I just bought two NuBox 311 for my desktop. While the sound is really nice, it lacks somewhat of the deeper bass I expected. The recommended way to compensate for that seems to be an ATM-311. But I only listen to sound coming from my Mac, so I was looking for a way to replace the ATM-311 hardware EQ with some (free) software.

This article is based on John Watson’s article OS X System Equalizer and some additional comments I found in the Nubert Forum. I use an Apogee Duet 2 USB sound card. The line outs are connected without any further devices inbetween to an amp which drives the speakers.

The 2-channel variant as described in John’s document above seems not to work for me, it never applies any effects (like the EQ we want here). Here are the steps I took using the 16 Channel SoundFlower:

  1. In System Audio Settings, set default system output to SoundFlower 16. There seems no way in MacOS X to configure which channel to use as a system-wide default, so it seems to always be channels 1 and 2 (even if the application allows choosing a dedicated audio device). By the way, iTunes seems to use the system device in all cases. But even VLC, which allows to choose the audio output device, does not allow setting which channels to use on that device.

    SoundFlowerDefaultSystemOutput

    After setting it, the little speaker symbol should show next to the SoundFlower 16 device.

    SoundFlowerDefaultSystemOutputResult

  2. In AU Lab, set input to SoundFlower 16, channels 1-2. Also set output to SoundFlower 16, channels 3-4.

    AULab Studio

  3. In SoundFlowerBed, set output to DuetUSB, channel 3 and 4.

    SoundFlowerOutputRoutedToDuet 3 4

  4. In Apogee Maestro, set the software return to be routed to channels 3-4.

    ApogeeMaestroMixer

  5. Still in Apogee Maestro, set the speaker output listen to channels 3-4.

    ApogeeMaestroOutput

  6. Back in AU Lab, add the EQ as described in the original document. Here is the one I use:

    CompensateNuBox311

  7. Note that AU Lab needs to run in order to apply the EQ.

Troubleshooting

Sometimes I get no sound after launching AU Lab. Then I simply go into SoundFlowerBed and click on the output device (in my case, DuetUSB in the SoundFlower 16 section) again. This seems to re-initialize whatever is hung up. The same solution seems to help when I get a constant noise instead of regular audio after twiddling with SoundFLower.

If that doesn’t help, change input or output to another device and back to SoundFlower 16. Then repeat the steps above.