Tone Roll Audio (Pro Mode) - Garrett AT Pro Owner's Manual

Tone Roll Audio (Pro Mode)

This feature of Pro Mode provides the user with more
audible target information to help identify targets, particularly
flat iron objects, such as bottle caps and washers. Standard
Mode audio produces a single tone based upon the target's
strongest signal. For flat iron objects, this single tone is often
the same as a good target. Tone Roll Audio, however, provides
a variance of target tones as the searchcoil approaches and
passes over the target. These varying tones of audio provide
better overall target information and identification.
Tone ID Comparison: Standard vs Pro Mode
Bottle cap
While in STD Mode, bottle caps, steel washers and other flat iron objects
often sound like good targets, producing a high tone response. This is
because the bottle cap's shape and flat surface resembles a coin which
can trick the detector. In PRO Mode, however, the bottle cap will produce a
very distinctive response with multiple tones. As shown, the bottle cap will
produce a distinctive response of Low-High-Low as compared to the coin's
response of only High tone.
18 Garrett Metal Detectors
Coin