Stereo Tool

-- note: this is a beta version to get feedback. --

Someone asked me to add a different stereo widening filter, based on what was used on some stations in the Netherlands in the 1990s.

The result sounds surprisingly good, and better than the old stereo filter.

What's different?
In the old Stereo filter, called Stereo Image, usually the phase differences were increased.
Advantange: No change in sound, each channel still contains the same sounds that it contained before increasing the phase differences.
Disadvantage: It sounds a bit unnatural, and when you listen to it in mono, you loose more sounds than without the stereo widening.

The new filter, called Stereo Boost, takes a different approach: The existing differences between the channels are exaggerated. This means that in the stereo signal, sounds that are different between the channels (usually mainly reverb etc.) are now louder. But when you convert the result to mono, you get exactly the same sound as when Stereo Boost is not used.

So how does it sound?
The result of the Stereo Boost filter usually sounds warmer than the old Stereo Image filter, and the stereo effect is much stronger. It also sounds more natural.

How to use it
In the beta version listed below, the presets still use the old style stereo widening. To change that:
- Go to the Stereo window. Here you now see 3 panels: AZIMUTH, Stereo Boost and Stereo Image.
- Turn Stereo Image off: Stereo Image and Stereo Boost don't really combine very well, and if you turn both on both the CPU load and the latency increase a lot.
- Turn Stereo Boost on.

The new sliders are:
- Stereo boost strength. The Stereo Boost filter tries to boost the stereo sounds to the maximum. This slider controls how strongly the stereo signal is pushed to the limits.
- Maximum stereo amplification. If a stereo sound is very soft, it might get boosted far too much, causing large changes in the sound. For example, a soft reverb might be amplified by a factor 20 if stereo boost strength is set to 20. This slider limits the maximum amplification of sounds. 3-4 seems to be a good range for this. You might need to set it lower if you have very low quality MP3s.
- max stereo level. If you want a constant stereo level, but not as strong as possible, this slider allows reducing the stereo level, while keeping it constant as a result of the stereo boost strength filter.
- Never reduce below original level. Checking this box makes sure that the stereo level never gets below the original stereo level. Basically, checking this box means "set the amount of stereo to 'max stereo level', but never below the original amount of stereo.

Downloads (BETA!)
Winamp DSP plugin: http://www.stereotool.com/download/dsp_ ... r_BETA.exe
Stand alone version: http://www.stereotool.com/download/ster ... r_BETA.exe
Command line: http://www.stereotool.com/download/ster ... d_BETA.exe
VST version: http://www.stereotool.com/download/vst_ ... l_BETA.dll

Hi Hans,
This is Good news!
This filter works very good. I like that if i push "stereo amplification" to MAX ... mono stays same and good thing is that "Stereo image" knows to increase bad side of mp3 files, with this filter this is not case.
For me this filter sounds more natural.

Found this settnigs for our transmitter 20.00/2.50./1.00 .. and it's OnAir alredy

btw
using Stereo Image and Stero Boost realy not good thing, so it can be done that only one can be turned ON.

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control point
control point2

Wow. It sounds so clean and warm now with the new stereo boost! I turned off Stereo Imaging and just left Stereo Boost at the default settings. It really does make the sound seem more natural. Great job Hans!

-n4-

I've just updated the presets, they now all use the Stereo Boost filter instead of the stereo image filter. (Except the presets that were created by others; Bojcha, for your presets I filled in 20 / 2.5 / 1 as you wrote earlier).

Great job Hans.
Actually i found 10 / 1.50 / 1 settings as final one.

btw i see ver is 4.10, any other changes?

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control point
control point2

Ok, updated.

I've also made a few minor adjustments to the stereo boost settings in the presets: Instead of limiting it by setting "max amplification" lower, I've now reduced the "stereo boost strength" - that seems give a bigger boost to the stereo signal without causing artifacts.

About 4.10: No really interesting changes. The minimum setting of the "Winamp gap detection" is lowered, and I've tightened the registration key checking mechanism.

Another small update: The stereo input and output level of Stereo Boost are now displayed, both in the Stereo and in the main window.

How can we use CENTER BASS option now?
And, what exactly is cut frequency for CENTER BASS ?

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control point
control point2

The best way to use CENTER BASS now is to enable the "Stereo Image Processing" panel anyway. But make sure that all the other settings are set to their defaults (phase and width 1.00, max 100% and 180 degrees etc.)

This will increase the CPU load and latency.

Cut frequency is 200-400 Hz (sliding scale).

Note: I have tried combining the 3rd panel with the AZIMUTH processing (as it was before), but performing this processing BEFORE Stereo Boost sounded horrible - it HAS to be done afterwards. And AZIMUTH HAS to be done before...

Do you really need it? Tracks with phase differences in the bass are very rare, and if you're not using Stereo Image Processing you're not increasing those phase differences anymore...

Actually i am not using "center bass" i was just testing some tracks to get stronger bass and some times i get better and stronger bass with "center bass" but frequency is not there where shuld be for this test.
Maybe i am testing in wrong way .. i'll back to multiband again.

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control point
control point2