Mac OS X or Linux: delay/timeshift audio input by ~10 seconds

Question

I would like to watch a baseball game on TV, but listen to the radio broadcast. The TV is about 10 seconds behind the radio, though.

Does anyone know a way to delay the input from my radio by 10 seconds and output it again to the speakers? I can do this on Mac OS X or Linux (or even Windows). I have Audio Hijack Pro, but there is no such effect.

thanks for any ideas!

Answer 1

This can be done using Audio Hijack Pro. First, set up your audio source and hijack it. Now, go to the effects tab. Add "AudioUnit Effect > Apple > AUDelay". In the pop-up window, set dry/wet mix to 100%, lowpass cutoff frequency at 22,050, and move the orange dot in the graph to 0% feedback with a 2 second delay (move the dot down and to the right). Since 2 seconds is the max delay per AUDelay effect, just set up 5 of them.

Answer 2

On a Mac, this (delaying a radio signal in order to sink with the MLB, or any other, broadcast) can also be accomplished with GarageBand and delay effects that are included in the software.

Run a male-to-male 3.5 mm cable from the headphone or line out from your radio to the audio input of your Mac (usually located next to the headphone out on Mac). Turn the audio on and set volume to about 1/3.

1. Open the ‘System Preferences’ application in your dock, and click the ‘sound preferences’ (speaker icon). Select the ‘input’ tab and ‘line in’ as the sound input source. You should see the ‘input level’ meter light up, indicating that the computer is seeing your source audio. Adjust the level with the slider so that the signal is not clipping.

2. Open GarageBand and create a new project.

3. In the lower right corner of the GarageBand window, be sure ‘input source’ is set to: ‘built-in input.’ In the setting below this, set ‘monitor’ to ‘on’.

4. Enable 'record' on the track that appears in the window (click the red button). Adjust the slider below the audio meters so that audio is not clipping.

5. Adding the delay: Click the ‘edit’ tab to the right of your GarageBand window.

   In the effects column, mouse over the bar that says ‘click here to add an effect’ and do that. Under “AU Audio Effects” select AUDelay. Mouse over the icon for the effect you’ve just added and you will see three sliding bars, click that.

   Change settings to: dry/wet mix: 100% (to take out the original signal) delay: maximum (I can’t get it to go past 2 seconds, even though the window suggests that I should be able to) feedback: 0% lowpass cutoff frequency: maximum (22,050 HZ)

   Repeat step 5, adding additional delays onto the signal until you get the delay you want. You can adjust the delay length on the final effect plug-in to achieve the desired result. Note: the track allows for 4 delay effects to be added, which gives you a maximum delay of 4 x 2 seconds or possibly more, depending on the version you are using of GarageBand and the AUDelay.

If you need more delay, you can click the ‘Master Track’ tab above the track ‘edit’ tab and, using the same procedure outlined in step 5 above, you add another delay unit to your chain and achieve a full 8-second delay.

If AUDelay does not give you enough of a delay, there a many free plugins that are GarageBand-compatible and have longer delay times. Voxengo is one of many software developers that offer a free sound delay plug-in (in Mac and Windows compatible versions) and their plug-in offers a 3 second delay (http://www.voxengo.com/product/sounddelay/). Installation is drag and drop, just check the website and follow the directions.

Finally, as these effects can add unwanted noise to your signal, use the visual EQ to process to your taste/system.