DownScan is new technology from Lowrance which gives us a different view of what is below the boat than traditional sonar view. The images are crisper and look more like what is actually being seen.
The reason why DownScan can do this is the shape of the transducer cone is narrower compared to sonar. Lowrance presently has two models for the DownScan. The Lowrance Elite DSI has one transducer for DownScan. The StructureScan transducer actually has three transducers for DownScan and SideScan. The outside ones are for the SideScan and the center transducer is for the DownScan. All three transducers have narrow cones but the difference is the outside transducers are aimed to look away from the boat and the center (DownScan) is aimed to look below the boat similar to a sonar transducer.

This image roughly shows the differences in the cone shape of the transducers as they view the bottom.

DownScan is great for target separation which helps us catch more fish. Fish that are close to each other are separated with the DownScan show up better as in this image.

Fish close to the bottom are separated from the bottom as shown in this comparison.

Weeds or grass make it difficult to interpret sonar. This image demonstrates how a good DownScan can separate bait, weeds and fish so you can make good decisions on where to fish.

These are just a few examples of the target separation and clarity of the DownScan. After using this new technology for over one year, I gave it a thumbs-up as a major advance in marine electronics.

For more information on using your sonar, GPS, Lowrance Structure Scan, or to get instructional DVDs by Doctor Bruce Samson aka Doctor Sonar at www.hightechfishing.com