UPMAX ISC uses the latest Linear Acoustic® upmixing algorithm for upmixing 2-channel audio to 5.1, and for upmixing 2-channel, 3-channel, 5.1-channel, and 7.1-channel audio to immersive formats including 5.1.4, and 7.1.2. If the channel count and format of the incoming content match the desired output format, UPMAX ISC will pass it through as-is.
The UPMAX menu is separated into Basic and Advanced sections. The Basic menu is displayed by default. The Advanced menu can be expanded with a dropdown menu as needed.
As explained in more detail in the Basic UPMAX Menu section, UPMAX ISC can create a multi-channel output in 5.1, 7.1, 5.1+4, and 7.1+2 formats.
This format includes Front Left, Front Right, Center, LFE, Left Rear Surround, and Right Rear Surround channels. The Left and Right Surround speakers are located behind and to the sides of the listener.
This format builds on 5.1 by including two additional surround channels which are referred to as "side" or "mid" surrounds. These additional speakers are placed at the listener's side halfway back in the room.
Channels include Front Left, Front Right, Center, LFE, Left Mid Surround, Right Mid Surround, Left Rear Surround, and Right Rear Surround.
Note that Dolby® officially designates the side surround channels as simply "Left Surround" and "Right Surround" and the rear surround channels as "Left Rear Surround" and "Right Rear Surround."
This format builds on 7.1 by including two additional overhead channels which are interchangeably referred to as "top," "height," or "overhead." These additional speakers are placed above the listener halfway back in the room.
Channels include Front Left, Front Right, Center, LFE, Left Mid Surround, Right Mid Surround, Left Rear Surround, Right Rear Surround, Left Top, and Right Top.
This format builds on 5.1 by including four additional overhead channels which are interchangeably referred to as "top," "height," or "overhead" (as in 7.1+2) but with the further designation of "front" and "rear." These additional speakers are placed above and both in front of and behind the listener.
Channels include Front Left, Front Right, Center, LFE, Left Rear Surround, Right Rear Surround, Left Front Top, Right Front Top, Left Rear Top, and Right Rear Top.
There is a fair bit of latitude (a polite way of saying "inconsistency") when referring to channels or groups of channels among manufacturers and technology companies. Supply chain issues have interfered with our plans to include a secret decoder ring in the box, so we'll clarify some terms as they are used in our menus here instead.
"Front" refers to the front speakers minus the Center channel, i.e., the Left Front and Right Front speakers only
"Center" refers to the center-channel speaker.
"Surround" collectively refers to anything other than the Front, Center, and LFE channels. Depending on the output format, this includes all rear, side, and height speakers.
"Side" refers to Mid Surround speakers in 7.1- and 7.1+2-channel formats.
"Rear" refers to the Rear Surround speakers in the context of 7.1- and 7.1+2-channel formats.
"Lateral" refers to any and all speakers except for overhead ("height") speakers, including Front, Center, LFE, and all Surround speakers.
"Height" refers only to the overhead ("height") speakers.
An overview and explanation of the upmixing controls.
The controls in the Basic menu can be divided into four basic groups: Format controls (1A), LFE Channel controls (1B), Center Width controls (1C), Gain controls (1D), and Auto-Detect controls (1E).
The Input Format menu (2A) is used to specify the channel format of the source audio. If the input format matches the selected output format (as selected with the Output Format control) the unit will pass the signal through as-is without additional processing. Input options include:
Auto Detect: In this mode, the unit continuously monitors the input signal to determine its format and will automatically switch to one of the processing modes below (Stereo, Stereo + Dialog, or 5.1)
Stereo: Stereo content will be upmixed to the desired output format
Stereo + Dialog: Stereo content will be upmixed to the desired output format, while a dedicated dialog input on Channel 3 will be passed through to the Center output
5.1: 5-1-channel content will be upmixed to the desired output format
Pass-through: Pass-through will pass the input signal directly through to the output with no additional processing; this can be used as a “soft bypass” function as the signal still runs through the upmixer and therefore incurs the same amount of latency as it would if it was actually upmixing a signal, thereby preserving A/V sync and avoiding lip-sync issues
When Auto Detect is selected, enabling the Center Detect control (2B) upmixes stereo content to the specified output format but ignores the presence of audio on Channel 3, which is typically dialog. The Channel 3 audio is time-aligned and summed with the upmixed version of the audio at the output. This is especially useful in sports production where announcer dialog is often routed on a separate bus, giving downstream facilities the option to edit or replace the announcer track.
The Output Format menu (2C) determines the output channel configuration. Output options include:
5.1: Provides a constant 5.1-channel output from Stereo, Stereo + Dialog, and 5.1-channel input sources.
5.1 Legacy: Like the standard 5.1 output, it provides a constant 5.1-channel output from Stereo, Stereo + Dialog, and 5.1-channel input sources but with upmixing that is sonically closer to the previous UPMAX algorithm used in the Linear Acoustic UPMAX v4 upmixer and the algorithm employed in the various Linear Acoustic AERO®-series processors.
7.1: Provides a constant 7.1-channel output from Stereo, Stereo + Dialog, 5.1-channel, and 7.1-channel input sources.
7.1+2: Provides a constant 7.1.2-channel output from Stereo, Stereo + Dialog, 5.1-channel, 7.1-channel, or 7.1.2-channel input sources.
5.1+4: Provides a constant 5.1.4-channel output from Stereo, Stereo + Dialog, 5.1-channel, or 5.1.4-channel input sources.
The LFE channel controls are used to tune the crossover frequencies, gain, and signal routing of the low-frequency effects audio.
The LFE Filter Frequency control (3A) defines the frequency at which audio below the setting is routed to the LFE channel and audio above is sent to the Lf, Rf, C, Ls, and Rs channels. The crossover is typically set at 80, 100, or 120Hz; the default is 80Hz. This control works in combination with the LFE Routing and LFE Gain controls to create the LFE Channel.
The overall gain level of the LFE channel is set by the LFE Gain control (3B). When set to 0.0dB, the same amount of gain below the frequency set in the LFE Filter Frequency control (3A) present in the original 2-channel audio (and, in turn, the total gain in all lateral channels after upmixing) will also be added to the LFE channel.
The LFE Routing control (3C) balances the amount of LFE content (audio below the LFE Crossover Frequency setting) sent to the LFE channel versus what remains in the Lf, Rf, C, Ls, and Rs channels.
Setting this control to 0.50 sends 50% of the audio to the LFE channel and leaves 50% in Lf, Rf, C, Ls, and Rs channels. A setting of 0 sends no audio below the crossover frequency to the LFE channel, while a setting of 1 sends all audio below the crossover frequency to LFE channels, effectively removing it entirely from the remaining channels.
These controls define the routing of the Center channel LF and HF bands across the Left, Center, and Right channels. Used in combination with the Mid-Bass Crossover frequency control, they provide the ability to craft the image of the Front channels in a way that maintains a direct sonic-visual association of dialog while providing a pleasant and wide image of the phase-correlated elements. Values are expressed in a decimal format but easily correlate to a percentage value (0.00 = 0%, 0.50 = 50%, 1.00 = 100%, etc.).
The LF Center Width control (4A) determines the amount of LF audio routed to the Center versus the Left and Right Channels.
The HF Center Width control (4B) does the same for audio in the HF band.
A setting of 0% sends all audio in the respective band to the Center channel, while a setting of 100% sends audio to the Left and Right channels only. Intermediate values provide a blend to create any desired mix.
The Center Gain control (5A) and Surround Gain control (5B) set the overall output gain of the center and surround channels respectively. The default value of 0dB for both controls will result in a downmix that adheres to Dolby's standard recommended settings.
The Master Gain control (5C) simultaneously sets the output gain of all channels.
When the Input Format is set to Auto-Detect, the UPMAX ISC continuously monitors the input signal to determine its format and will automatically switch between upmixing to the selected Output Mode and pass-through.
The level at which the detector circuit determines that the incoming signal is program audio (and not noise or silence) is set by the Auto-Detect Threshold control (6A). The proper setting depends largely on the quietness (or noisiness) of channels that are not muted but also contain no audio. Set too low, it may cause a false trigger to upmix; set too high, it may cause a late transition to upmixing. The default value of -70dB should work well for modern production while values as high as -63dB may be required for noisy sources.
The amount of time in milliseconds a signal must stay above the Auto-Detect threshold before the unit begins upmixing - or below the threshold to cease upmixing - is determined by the Input Switch Transition control (6B). A value between 10ms and 12ms is a good starting point for most material.
Important: The settings of the Center Gain and Surround Gain controls have an important impact on the downmixed signal. Please read and understand the section before adjusting these settings.
"Downmixing" refers to the process of mixing a certain number of audio channels to create an output with fewer channels. The most common type of downmix in TV audio involves creating a stereo (2-channel) version of 5.1-channel content so that all program elements, regardless of their original channel routing, can be heard in the mix when listening on a typical stereo television.
The controls in the UPMAX ISC Downmix menu allow the downmix format to be specified, determine whether <<FUTURE - SOMETHING ABOUT LFE ON>>, and trim the gain of several channels and channel groups.
This control allows UPMAX ISC to create a stereo downmix from any of its multichannel output formats when set to "Stereo," or create a 5.1-channel downmix from a 7.1, 7.1.2, or 5.1.4 upmix.
This control allows the gain of the audio originally mixed to the center channel to be reduced (by as much as 70dB) or boosted (by as much as 6db) when the downmix is created. Setting the Center Trim control higher than the Height and Surround Trim controls can help ensure that dialog - the most common component of the center channel and the most critical channel in terms of program intelligibility - doesn't get overwhelmed by music and effects.
This control allows the gain of the audio originally mixed to the height channels in 7.1.2 and 5.1.4 formats to be reduced or boosted when the downmix is created.
This control allows the gain of the audio originally routed to the LFE channel in multichannel formats to be reduced or boosted when the downmix is created.
This control allows the gain of the audio originally routed to the surround channels in multichannel formats to be reduced or boosted when the downmix is created.
When enabled, this control includes audio originally routed to the LFE channel to be included in the downmix.
The settings of the Center Gain and Surround Gain controls in the Basic UPMAX menu and the Front Gain LF, Front Gain HF, Front Height Gain LF, Front Height Gain HF, Rear Gain LF, Rear Gain HF, Rear Gain LF, and Rear Gain HF controls in the Advanced UPMAX menu will affect the gain of the downmixed signal differently compared to the upmixed signal.
In the case of the Center Gain control, which focuses on a single channel that is almost always reserved just for dialog, the translation from a multi-channel output to a downmixed output is fairly predictable and straightforward.
However, with a parameter such as the Surround Gain control - which encompasses four audio channels (Left Mid Surround, Right Mid Surround, Left Rear Surround, and Right Rear Surround) in 7.1 or 7.1.2 formats - it is important to remember that whatever content is present in all four channels will be rendered at the same level in the downmix. The same is true for the remaining controls relative to the channels they incorporate.
The Advanced parameters are included for audio experts who wish to dig deep and tweak settings for very specific applications and needs. They are not required for most users and are accordingly not displayed by default.
NOTE: Some advanced controls - specifically those relating to additional side and height channels - will be grayed out if they do not apply to the selected output format.
NOTE: To minimize the amount of vertical scrolling required when reading the control descriptions below and referencing the image of the menu, the identical figure is included twice - once here at the beginning of the section, and once again at the very end.
Though included in the current UI, the functionality of this control has been removed and should therefore be disregarded.
This control adjusts the balance between the front channels (minus the center channel) and all supported surround channels for frequencies above the value set in the LFE Filter Frequency control. A setting of 1.0 routes 100% of the audio to the front channels and 0% to the rear. The default setting of 0.5 results in a 50/50 split.
This control adjusts the crossover point between the Front Left and Right channels and the Front Height channels when upmixing to 5.1.2, 5.1.4, and 7.1.2 formats. The crossover is very gentle, and the effect of this control is subtle. The audio spectrum in the Front Height channels is determined by a combination of this control and the Lows in Heights control (1R).
This control adjusts the gain of the Front Left and Right channels at frequencies lower than the crossover point set in the Front/Front Heigh Crossover Frequency control (1C).
This control adjusts the gain of the Front Left and Right channels at frequencies higher than the crossover point set in the Front/Front Heigh Crossover Frequency control (1C).
This control adjusts the gain of the Front Height channels at frequencies lower than the crossover point set in the Front/Front Height Crossover Frequency control (1C).
This control adjusts the gain of the Front Height channels at frequencies higher than the crossover point set in the Front/Front Heigh Crossover Frequency control (1C).
This control adjusts the crossover point between the surround channels and the Rear Height channels when upmixing to 5.1.2, 5.1.4, and 7.1.2 formats.
This control adjusts the gain of all surround channels at frequencies lower than the crossover point set in the Rear/RearHeigh Crossover Frequency control (1H).
This control adjusts the gain of all surround channels at frequencies higher than the crossover point set in the Rear/RearHeigh Crossover Frequency control (1H).
This control adjusts the gain of the Rear Height channels at frequencies lower than the crossover point set in the Rear/Rear Height Crossover Frequency control (1H).
This control adjusts the gain of the Rear Height channels at frequencies higher than the crossover point set in the Rear/Rear Height Crossover Frequency control (1H).
Important: The settings of the Front Gain LF, Front Gain HF, Front Height Gain LF, Front Height Gain HF, Rear Gain LF, Rear Gain HF, Rear Height Gain LF, and Rear Height Gain HF controls have an important impact on the downmixed signal. Please read and understand the Upmixing Controls That Affect the Downmix section before adjusting these settings.
The comb filter is used to separate different frequency components of the input signal to aid in steering sounds in the surround field between the front and rear channels. This control defines the number of "teeth" there are in one octave of frequency change of the comb filter.
Integer values (that is, a value that is a whole number) ensure that the harmonics generated in the upmixing process are steered to the same channel as the fundamental frequency and result in a livelier sound.
Fractional half values (that is, a value that ends in .5, including the default setting of 2.5) route the fundamental frequencies and odd harmonics to the same channel (either the front or rear), and even harmonics to the other channel (whichever is not receiving the fundamental and odd harmonics). This renders a soundfield that is more stable but consistently wide.
This control sets the lowest frequency of the comb filter.
This control sets the overall gain of the comb filter. It can have a significant impact on the movement of audio between the front and rear channels, with higher values rendering a greater sense of depth. In nearly all cases, leaving this control at its default setting will result in the most pleasing soundfield.
This control determines the amount of upmixed sound pushed to the surround channels and is analogous to the "Surround Depth" control in previous UPMAX versions. A value of 0 sends all audio to the Rear channels while a value of 1 sends no audio to the Rear channels. A value of 67 sends 33% of the audio to the Rear channels and keeps 67% of the audio in the Front channels.
This control determines to what degree higher frequencies from the Front/Front Height Crossover and Rear/Rear Height Crossover circuits are mixed back into the lateral speakers when upmixing to 5.1.4 and 7.1.2 output formats. The audio spectrum in the lateral channels is determined by a combination of this control and the Lows in Heights control (1R).
The control determines to what degree lower frequencies from the Front/Front Height Crossover and Rear/Rear Height Crossover circuits are mixed back into the height speakers when upmixing to 5.1.4 and 7.1.2 output formats. The audio spectrum of the height channels is determined by a combination of this control and the Highs in Laterals control (1Q).
This control adjusts the crossover point of the Left and Right Side ("Mid") Surround channels and the Left and Right Rear channels when upmixing to 7.1, 7.1.2, and 5.1.4 output formats.
This control adjusts the gain of the Side and Rear channels at frequencies lower than the crossover point set in the Side/Rear Crossover control (1S) when upmixing to 7.1 and 7.1.2 output formats. A setting of 0 routes 100% of the signal to the Rear channels; a setting of 1 routes 100% of the signal to the Side channels; a setting of 0.5 sends 50% of the signal to each.
This control adjusts the gain of the Side and Rear channels at frequencies higher than the crossover point set in the Side/Rear Crossover control (1S) when upmixing to 7.1 and 7.1.2 output formats. A setting of 0 routes 100% of the signal to the Rear channels; a setting of 1 routes 100% of the signal to the Side channels; a setting of 0.5 sends 50% of the signal to each.
This control simultaneously adjusts the gain of all height speakers when upmixing to 7.1.2 and 5.1.4 formats.
