Basic function

This effect converts stereo (2ch) material into 4ch surround.
Reproduces a pseudo surround sound by sending L and R inputs to Ls and Rs.
A 3-band equalizer can be used for the front (L, R) output and the surround (Ls, Rs) output.

Number of channels

Input: 2ch(L, R)(0, 1)
Output: 2ch(Ls, Rs)(3, 4)

Features

Simple 4ch playback from 2mix material.
Using the equalizer, you can create differences between front and surround for each band.
Bypass can be switched from the program at run time. For example, you can switch bypass according to the number of channels of the playback device (2ch or 5.1ch).

Attention: If a signal that has been upmixed to 4ch by applying the surrounder is downmixed to stereo, extreme deterioration of sound quality will occur.
If you want to output in stereo, we recommend that you enable bypass.

Settings related to surround

Item	Description	Initial value	Lower limit	Upper limit
Mode	The method for sending the original signal to the surround (Ls, Rs). For details on the setting values, see "Surrounder Mode" below.	Straight	-	-
Max Delay Time	The maximum delay value. *1	100.0 msec	0.00 msec	500.00 msec
Delay Time	The delay value of the surround (Ls, Rs) relative to the front (L, R).	50.00 msec	0.00 msec	500.00 msec (Depends on the maximum delay value)
Surround Gain	The output level of Ls, Rs.	-6.00 dB	-96.00 dB	48.00 dB
Mute Front	When enabled, mutes the L, R output.	False	-	-

1 Initial value at runtime, affecting the size of the work area.

Surrounder Modes

Item	Description
Straight	Sends from L -> Ls, R -> Rs. A simple sound spread.
Cross	Sends from L -> Rs, R -> Ls. Because the left and right are inverted, an effect similar to the reflected sound of an arena is obtained. It is easier to adjust the value if you think of the delay due to distance as delay and the attenuation due to distance as gain.
Matrix	Sends from L-R -> Ls, R-L -> Rs. The center component is canceled and the remaining component spreads to the rear. We recommend that you set the delay value as small as possible and adjust only with gain.

Setting items related to equalizer

You can set the values ??of the 3-band equalizer for the front (L, R) output and the 3-band equalizer for the surround (Ls, Rs) output separately.

Item	Description	Initial value	Lower limit	Upper limit
Enable band (ENABLE)	Switch between enabling and disabling the band.	True	-	-
Band Type (TYPE)	You can select the band type from low shelf, peaking, and high shelf.	Low shelf, peaking, high shelf	-	-
Frequency (FREQ)	The frequency value of the band.	Varies for each band	0 Hz	24000 Hz
Gain (GAIN)	The gain value of the band.	0.00 dB	-24.00 dB	24.00 dB
Quality (Q)	The quality factor value of the band. The smaller the value, the gentler the slope. The larger the value, the steeper the slope.	1.00	0.10	10.00