I used one last year, and asked the same question on another forum. This is the reply I got, and have been using these settings:
Garmin sonar settings
I have two different Garmin sonars … EchoMAP CHIRP 53dv and EchoMAP Plus 95sv … and also both ice transducers above. Targeting perch and walleye typically in 20-30 FOW always using ‘Traditional Sonar’ with ‘Split Zoom’; zoom window on the left and full water column on the right. Following are some of my preferred sonar settings for the 95sv; almost all settings stay the same between uses (i.e. cycling the power) until you change them again.
‘Menu – Zoom – Split Zoom – [On].
‘Menu – Range’ set to [Auto] and ‘Zoom’ set to [Manual] with a 5ft zoom window.
‘Menu – Sonar Setup – Scroll Speed’ set to [Ultra].
‘Menu – Sonar Setup – Advanced – Interference’ set to [Off] and ‘Surface Noise’ set to [Hide].
‘Menu – Sonar Setup – On-screen Control’ set to [Gain].
‘Menu – Sonar Setup – Appearance – Color Scheme’ set to [Classic Blue].
‘Menu – Frequency’ usually set to [CHIRP] but I sometimes check out different ‘Beam Width’ settings … interesting to see the return signal change while cycling through the different settings. The GT10HN-IF ice ‘ducer provides 7-16 degree beam width and the 8HW-IF 16-24 degrees.
I want the lure return signal to always be visible but as fine as possible so, depending on depth etc, will usually have the ‘Gain’ somewhere between 40% – 60% accordingly.
I typically have the Backlight set at 30-50% evenings or inside a shanty, and 50-70% outdoors in daylight.
By the way, the EchoMAP Plus 95sv touch screen with keyed-assist features are absolutely AWESOME! (Also applies to EchoMAP Plus 7x models.) Simple two-finger motion to resize the zoom window or single finger swipe to move the zoom window anywhere within the water column. Four ‘memory’ keys to instantly jump to your most frequently used screens in any combination of sonar and/or navigation. Choice of On-screen Control … Off, Gain or Range.