Humminbird sounder combos, use of Down Imaging and explanations

In addition to Dual Spectrum, some Humminbird units are equipped with Mega Down Imaging technology. Let's take a look at the use and settings of Mega Down Imaging technology on Humminbird fishfinder handsets distributed by Navicom.

Grégory Martin Published on November 22, 2023

Mega Down Imaging technology complements 2D (Dual Spectrum) technology. It offers greater sharpness and precision.

Down Imaging/Dual Spectrum

The question is often asked as to the benefits of working with Down Imaging (DI) compared to Dual Spectrum (DS, formerly known as 2D). These two technologies are complementary. They are different, with different beams and therefore different detection cones.

Dual Spectrum (DS)

Dual Spectrum works in a cone, while Down Imaging (DI) works on a beam that is more or less flat and wider than the DS. As a result, we see elements with DI that we don't see with DS:

Greater precision, because the frequency is higher. The DS averages what it detects in the cone.
DI working in a beam enables more effective target discrimination.

Frequency ranges

There are three frequency ranges on the DI:

Mega: use from 0 to 15 m, but take into account the color of the water (charged or not...)
The 800: 15 m to 25/30 m
Le 455: 25/30 m at 70/80

Freshwater tips

The Mega range is set from 1000 to 1300 for greater sharpness.

Sensitivity/Contrast

First of all, you need to find the right frequency range (to be adapted according to the depth and turbidity of the water...).

Set the sliders in the middle to return to a correct setting. Of course, sensitivity/contrast settings in 455 will not be the same in Mega.

Sensitivity: display the sharpest possible image without "burning" the background.

Once the sensitivity has been set, the contrast can be adjusted. Basically, in most cases, the adjustment is made from -3 to +3. This is the standard base setting. Here again, the aim is to achieve the sharpest possible image, free from noise, i.e. without any noise appearing on the screen. When the background differs by 5/6 m, you'll need to readjust the contrast and therefore the sensitivity, otherwise leave the settings as they are.

Down Imaging (DI) technology is the perfect complement to Dual Spectrum (DS) technology. With this added technology, your Humminbird fishfinder handset takes performance to a whole new level.