Playing an MP3 Through the Boss GT-8

Playing an MP3 through the GT-8 will allow you to play along to your favorite tracks. You can even create a dedicated “playlist” patch that you can trigger between sets to send music to the PA. The GT-8 provides a LOOP feature that allows you to connect external equipment, and it can be used as an auxiliary input.

Playing a song through the GT-8 also allows you to determine the frequency response of the equipment you’re connected to. For example, if you are connected to a system that doesn’t have FRFR (full-range, and flat response,) you can use the GLOBAL EQ to make necessary adjustments. The GLOBAL EQ affects all patches stored in the GT-8. In general, if you’re connecting to a system that sounds radically different than the one that you created your patches on, the GLOBAL EQ is there to help.

The GLOBAL EQ can be accessed by pressing OUTPUT SELECT and using the JUMP parameters (< >) and the value dial to make adjustments. By default, the GLOBAL EQ should be set flat.

In summary, playing a song through the GT-8 presents several benefits:

• Adjust the GLOBAL EQ to match the frequency response of a non-FRFR system.
• Play along to your favorite tracks.
• Identify the characteristics of another guitar sound so that you can create custom patches.

The LOOP feature was essentially designed for connecting unbalanced equipment such as signal processors and guitar pedals. It does, however, provide a stereo RETURN that can be placed anywhere in the signal path. For the purposes of an auxiliary input, the LOOP should be moved to the end of the signal path.

• Press FX CHAIN.
• Press the right (>) JUMP parameter consecutively to move the cursor to the end of the chain.
• Press LOOP to move the effect.
• Press EXIT.

The LOOP can be used in several different ways. To use it as an auxiliary input, you need to set it to DIRECT MIX mode. This mode allows you to hear audio from the LOOP return, and the direct sound (your guitar) at the same time (in parallel). The BRANCH OUT mode uses only the SEND and the NORMAL mode is for connecting effects in series.

• Press LOOP.
• Rotate the value dial to select DIRECT MIX.
• Use the right JUMP (>) parameter to select and adjust the RETURN LEVEL.
• Activate the LOOP by pressing LOOP again.
• Press EXIT.
• You can save your new settings by pressing WRITE twice.
• Deactivate the LOOP when you are done tweaking by pressing LOOP twice and then EXIT.

The LOOP presents a final challenge. Because it was designed for unbalanced audio equipment, you will need to convert your balanced audio signal into an unbalanced one. This is done using a re-amp box (similar to a DI, but essentially in reverse.) Unfortunately, a re-amp box can be pricey considering such a simple application. The good news is that, as the name implies, it can also be used to “re-amp” your guitar signal for recording, allowing you to change settings on the GT-8 after you have already recorded your tracks. The re-amp box will need to be a stereo one (2 inputs and outputs) to work properly with an audio file. I recommend the Radial EXTC Stereo (~$400).

Here’s a typical signal path for connecting a mobile phone or iPod to the Boss GT-8. Note which cables are used (an unbalanced cable is used between the re-amp box and the RETURN.)

Frequency Response

You can use a frequency analyzer to assess the output of your GT-8’s signal. Place a frequency analyzer on an MP3 file of your choice, and then send the same MP3 file through the GT-8. Use a frequency analyzer on the GT-8’s input signal to check if the response is the same.