The VOICE switch on the Halcyon Green Overdrive selects between two different “mid humps”. The 808 setting is the stock voicing of the TS808 Tube Screamer, warm in character and boosting across a relatively wide range of mid frequencies. This setting works particularly well for fattening up single coil pickups for a thick blues lead tone. The MOD setting moves the mid hump slightly further up the frequency range, with a more focused peak. This setting is well suited to humbuckers, especially the neck position, adding some “bite” without too much extra warmth. The MOD setting is also useful from Metal players boosting high-gain amps, as it adds an aggressive edge to the tone.