HAAS-49 turns a mono signal into stereo using the Haas effect: a short delay on one channel (typically the right) creates the impression of width and direction without adding a second source. The plugin also gives you per-channel EQ (low, mid, and high gain for left and right) so you can shape the tone of each side, plus a stereo width control and optional saturation on each channel. This description covers the core behaviour before phase and polarity options; the plugin is mono in, stereo out.
 
Haas effect. You set the delay time (how many milliseconds one channel is delayed) and the amount (how much of the delayed signal is mixed in). Small delays (roughly 5 to 35 ms) produce a clear stereo image; the exact range depends on the plugin implementation. Amount at zero leaves the image unchanged; increasing it emphasizes the Haas effect. The result is useful for making mono recordings (vocals, synths, samples) feel wider or for gentle stereo enhancement.
 
Per-channel EQ. The left channel has three bands: low, mid, and high. Each band has a gain control so you can boost or cut that region on the left. The right channel has the same three bands independently. That lets you balance or colour the two sides differently (e.g. slightly brighter on one side, or more low on the other) while keeping the Haas timing intact.
 
Stereo width and output. A stereo width control adjusts the perceived spread of the output. Output gain trims the level so you can match bypass.
 
Saturation (per channel). Left and right can each have a saturation type (e.g. off, or different saturation flavors). This adds harmonic character per side if you want it.
 
Ideal for producers and mix engineers who want mono-to-stereo width and basic per-channel tone shaping in one place.