Reverb algorithms and parameters

Common effect device parameters

While the specific parameters for the RV7000 Mk II effect device are described below, some features and procedures are common to all effect devices. Please, refer to “Common effect device features” for information about the Input meter, the Bypass/On/Off switch and Signal Flow Graphs on the effect device.

About the main panel parameters

On the main panel you find three parameters that are available for all algorithms:

| Parameter	| Description
Decay	This governs the length of the reverb or the feedback if an echo algorithm is selected.
HF Damp	Controls how quickly the high frequencies should decay in the reverb. Raise it to gradually remove high frequencies, making the reverb sound warmer and less bright.
HI EQ	This is a high-shelving EQ that works much like a typical treble control on a mixer or amplifier. Lower the setting for a softer reverb sound or raise it to get more high frequencies.

Selecting an algorithm

You select a reverb algorithm in the remote programmer panel:

1.	Click the remote programmer arrow button on the main panel to display the remote programmer panel.

2.	Make sure the Edit Mode button is set to Reverb.

3.	Use the top left dial to select a reverb algorithm.

The selected algorithm is shown in the display next to the dial.

Here’s a quick overview of the ten algorithms - for details and parameter descriptions, see below.

| Algorithm	| Description
Small Space	Emulates a small enclosed space (a small room or a resonant body).
Room	Emulates a room with adjustable shape and wall character.
Hall	Emulates a hall.
Arena	Emulates a large arena, with separate pre-delay for the left, right and center reverbs.
Plate	Emulates a classic plate reverb.
Spring	Emulates a spring reverb, as used in e.g. guitar amplifiers.
Echo	An echo effect with gradually diffusing echo repeats. Can be synced to Reason’s tempo.
Multi Tap	A multi-tap delay with four different delay lines and tempo sync.
Reverse	A reverse reverb that “pushes” the dry sound to appear after the reverb. The result is a backwards reverb leading up to the direct sound.
Convolution	The zero-latency Convolution algorithm uses impulse response samples. The samples are used for generating the desired reverb effect (or actually any type of effect - depending on what sample you use).

Small Space

This algorithm places the sound in a small enclosed space, ranging from a tiny resonant body to a room. The parameters are:

| Parameter	| Description
Size	The size of the emulated space.
Mod Rate	The reverb can be randomly modulated for a more even sound (or for special effects). This parameter sets the rate of modulation (the amount is set with Mod Amount).
Room Shape	Select from four different room shapes, affecting the character of the reverb.
LF Damp	Controls how quickly the low frequencies should decay in the reverb. Raise it to gradually remove low frequencies, making the reverb sound “thinner” and less boomy.
Wall Irreg	Adjusts the positioning of the emulated walls in the small space. The lowest setting emulates two directly opposed walls while higher settings emulate more walls and angles, for a more complex resonance.
Predelay	Sets the predelay time, i.e. the delay between the source signal and the start of the reverb.
Mod Amount	Sets how much the reverb will be modulated. Use fairly low settings when emulating real rooms and resonant bodies, and higher settings for special effects.

Room

Emulates a medium-sized room, with the following parameters:

| Parameter	| Description
Size	The size of the emulated room.
Diffusion	At low Diffusion settings, you will hear the individual reverb “bounces” more clearly, while higher settings produce a more “smeared”, dense and even reverb.
Room Shape	Select from four different room shapes, affecting the character of the reverb.
ER->Late	The first “answers” in the reverb are called early reflections (ER) and are typically more pronounced than the actual reverb tail. This parameter sets the time between the early reflections and the reverb tail. This is set as a percentage - the actual delay time depends on the Size setting.
ER Level	Adjusts the level of the early reflections. “0” is normal level.
Predelay	Sets the predelay time, i.e. the delay between the source signal and the start of the early reflections and reverb.
Mod Amount	Sets how much the reverb will be modulated. Moderate modulation gives a natural, less static sound.

Hall

Emulates a hall. The parameters are the same as for the Room algorithm above (but the Hall algorithm offers larger Size settings).

Arena

Emulates the ambience in an arena or concert hall, with long pre-delay times (separate for left, right and center):

| Parameter	| Description
Size	The size of the emulated arena or hall.
Diffusion	At low Diffusion settings, you will hear the individual reverb “bounces” more clearly, while higher settings produce a more “smeared”, dense and even reverb.
Left Delay	The predelay time for the left side of the reverb.
Right Delay	The predelay time for the right side of the reverb.
Stereo Level	Adjusts the level of the left and right sides of the reverb. “0” is normal level.
Mono Delay	The predelay time for the mono (center) reverb signal.
Mono Level	Adjusts the level of the mono (center) reverb signal. “0” is normal level.

Plate

A classic plate reverb, excellent for vocals for example. The parameters are:

| Parameter	| Description
LF Damp	Controls how quickly the low frequencies should decay in the reverb. Raise it to gradually remove low frequencies, making the reverb sound “thinner” and less boomy.
Predelay	Sets the predelay time, i.e. the delay between the source signal and the start of the reverb.

Spring

An emulation of a spring reverb as can be found in guitar amplifiers, organs, etc. The spring reverb has the following parameters:

| Parameter	| Description
Length	Sets the length of the simulated spring.
Diffusion	At low Diffusion settings, you will hear the individual reverb “bounces” more clearly, while higher settings produce a more “smeared”, dense and even reverb.
Disp Freq	When sending a signal to a real-life spring reverb, the initial transient will produce a quick, characteristic sweeping tonal noise. This is because different frequencies in the sound are delayed by different amounts (a phenomenon called dispersion). This parameter controls the frequency of that sound.
LF Damp	Controls how quickly the low frequencies should decay in the reverb. Raise it to gradually remove low frequencies, making the reverb sound “thinner” and less boomy.
Stereo (on/off)	Determines whether the output of the spring reverb should be in mono or stereo.
Predelay	Sets the predelay time, i.e. the delay between the source signal and the start of the early reflections and reverb.
Disp Amount	Sets the amount of dispersion effect (see Disp Freq above).

Echo

This is an advanced echo effect, with diffusion controls and tempo sync. When Echo is selected, the Decay control on the main panel controls the echo feedback (the number of echo repeats). The parameters are:

| Parameter	| Description
Echo Time	Sets the time between each echo. When Tempo Sync (see below) is off, the echo time is set in milliseconds (10 - 2000 ms); when Tempo Sync is on you set the echo time as a number of 1/16 notes or 1/8 triplet notes, in relation to the current song tempo.
Diffusion	When this is set to 0, the echo will sound as a standard delay with clear, precise repeats. Raising the Diffusion setting will introduce additional echoes very close to the “main” echo repeats, causing a “smeared” echo sound. This will also expand the echo stereo image.
Tempo Sync	Determines whether the echo time should be freely set (“off”) or synchronized to Reason’s tempo (“on”).
LF Damp	Controls how quickly the low frequencies should decay in the echoes. Raise it to gradually remove low frequencies.
Spread	Adjusts the spacing of the additional echoes added by the Diffusion parameter. For a very smeared echo (sound more like a reverb), set both Diffusion and Spread to their maximum values.
Predelay	Sets an additional delay time before the first echo repeat.

Multi Tap

The Multi Tap delay produces up to four different delays with separate delay times, panning and level. The whole set of four delay taps can then be repeated at a given rate. Again, the Decay control on the main panel controls the feedback (the number of repeats for the whole multi tap set). All delay times can be tempo synced.

Note: this algorithm is handled a bit differently since you make separate settings for each delay tap:

•	The parameters to the left of the display are common for all taps.

•	You use the Edit Select parameter in the top right corner to select which tap to make settings for - the three parameters below affect the currently selected tap.

Tap 2 selected for editing.

•	You can also set Edit Select to “Repeat Tap” - this is where you specify the repeat time for the whole multi tap “package”.

With short Repeat times, the first tap may be repeated before the last tap has sounded. This can be used to create very complex multiple delay effects.

The common parameters (to the left) are:

| Parameter	| Description
Tempo Sync	Determines whether the delay times and repeat times should be freely set (“off”) or synchronized to Reason’s tempo (“on”).
Diffusion	Raising the Diffusion setting will introduce additional echoes very close to the “main” repeats, causing a “smeared” delay sound.
LF Damp	Controls how quickly the low frequencies should decay in the echoes. Raise it to gradually remove low frequencies.

When Tap 1 - 4 is selected with the Edit Select parameter, you can make the following settings for the selected delay tap:

| Parameter	| Description
Tap delay	Sets the delay - the time from the source signal to the tap. When Tempo Sync is off, the delay time is set in milliseconds (10 - 2000 ms); when Tempo Sync is on you set the delay as a number of 1/16 notes or 1/8 triplet notes, in relation to the current song tempo.
Tap level	Adjusts the level of the selected tap.
Tap pan	Adjusts the pan of the selected tap.

When Repeat Tap is selected with the Edit Select parameter, there is only one parameter to the right in the display:

| Parameter	| Description
Repeat Time	Sets the time between each repeat of the whole multi tap set. The number of repeats is set with the Decay control on the main panel. When Tempo Sync is off, the repeat time is set in milliseconds (10 - 2000 ms); when Tempo Sync is on you set the repeat time as a number of 1/16 notes or 1/8 triplet notes, in relation to the current song tempo.

Reverse

The Reverse reverb algorithm in RV7000 Mk II is special in that it actually “moves” the source audio as well. Sounds fed into the Reverse reverb are “sampled”, a reverse reverb is created and played back and finally the “sampled” original sound is played back. For example, if you feed a snare drum hit into the Reverse reverb, you will hear a rising “backwards” reverb, followed by the snare drum hit.

Therefore, you probably don’t want to hear the first, original (dry) sound. There are two ways to set this up:

Connect the RV7000 Mk II as an insert effect and make sure the Dry/Wet control on the main panel is set fully to “Wet”.

Connect the RV7000 Mk II as a send effect using one of the Sends on the Mixer, activate the Prefader (PRE) switch for the send and lower the mixer fader completely for the source signal.

That way, the signal will be sent to the reverb but the dry sound from the Mixer channel isn’t heard. Again, the Dry/Wet control should be set to “Wet”.

Note that with this algorithm, raising the Decay setting on the main panel will make the reverse reverb start earlier and build up under a longer time. Similarly, the HF Damp parameter affects how fast the high frequencies are built up in the reverse reverb. In the remote panel, the Reverse algorithm has the following parameters:

| Parameter	| Description
Length	This sets the time from when the source signal is fed into the reverb until it is played back again. It is during this time you will hear the reverse reverb, as shown in the display. The time can be set in milliseconds or as note values, depending on whether Tempo Sync is off or on. Note: As stated above, the Decay setting determines the length of the actual reverse reverb - in essence how soon it starts after the source signal. But of course, the reverse reverb cannot start before the original source signal! If you set Decay to a longer time than the Length setting, the reverse reverb will start abruptly, immediately when the source signal is fed into the reverb. If this sounds complicated, just take a look at the RV7000 Mk II display and try the settings - you will soon see how it works. Note also that very high Length settings demand a lot of processor power. This can be reduced by adjusting the Density parameter, see below.
Density	Density governs the “thickness” of the Reverse effect. If this parameter is turned down to zero, the effect produces individual delays rather than a dense “wash”, which can be used as a special effect. Worth noting is that if Density is set to around 50%, this can considerably reduce the CPU load without altering the sound of the effect too much. Exactly how much the Density parameter can be reduced without altering the sound depends on the source material.
Rev Dry/Wet	Sets the balance between the “moved” source signal (“dry”, low values) and the reverse reverb (“wet”, high values).
Tempo Sync	Determines whether the Length setting should be freely set (“off”) or synchronized to Reason’s tempo (“on”).

Convolution

The zero-latency Convolution algorithm uses impulse response samples to generate effects. Basically, “convolution effects” are the results of multiplying the frequency spectra of the input signals with the frequency spectra of impulse response samples, and thus generating a signal with the “character” of the impulse response sample. If the impulse response sample is a recording of the reflections of a large room, for example, the resulting effect will be “the input audio signal played back in a large room”.

RV7000 Mk II comes with three built-in preset impulse response samples. You can also use any other samples for the convolution algorithm, to generate all kinds of reverbs and special effects. You can even sample your own impulse responses and use in the convolution algorithm in RV7000 Mk II.

Propellerhead have gathered a large number of impulse responses and collected them in a free ReFill, along with lots of patches for the RV7000 Mk II and the Combinator. The ReFill is called "RV7000 mkII patches" - download it for free from shop.propellerheads.se!

Note that in the Convolution algorithm the input signals for the effect are first summed to mono (except in Parallel Stereo Mode (see “Stereo Mode”)) and then processed with the impulse response sample. The figures below shows the signal routings in the Convolution algorithm:

In the remote panel, the Convolution algorithm has the following parameters:

| Parameter	| Description
Sample Preset	Here you select one of the preset impulse response samples - plus your own sample (if you use that, see “Loading impulse response samples”).
Length	Sets the length (end point) of the currently used impulse response sample.
Size	Simulates the “size” of the impulse response sample, in practice its pitch, in semitone steps. -12 means pitching up the impulse response sample 1 octave and 12 means pitching it down 1 octave.
LF Damp	Controls how quickly the low frequencies should decay. Raise it to gradually remove low frequencies, making the effect sound “thinner” and less boomy.
Stereo Mode	Determines how the output signal should be presented. Note that the stereo effect is derived from the impulse response sample itself. So, the wider the stereo effect in the impulse response sample, the wider the stereo effect in the output. Note that if you use a mono impulse response sample, all effects below will be in mono! Stereo: The input signals are summed and then a stereo effect with a spread of 100% is applied. Stereo75%: The input signals are summed and then a stereo effect with a spread of 75% is applied. Stereo50%: The input signals are summed and then a stereo effect with a spread of 50% is applied. Stereo25%: The input signals are summed and then a stereo effect with a spread of 25% is applied. Mono: The input signals are summed and then the effect is panned to a centered mono signal (0% spread). M->S Slow: From Mono slowly panned out to full Stereo. M->S Fast: From Mono quickly panned out to full Stereo. S->M Slow: From full Stereo slowly narrowed down to Mono. S->M Fast: From full Stereo quickly narrowed down to Mono. Parallel: Individual processing of the two L and R stereo input signals (dual mono).
Predelay	Sets the predelay time, i.e. the delay between the source signal and the start of the convolution effect. A negative predelay masks the start of the sample, so if the sample has unwanted initial transients or silence, these can be “removed”.
Gain	Sets the amplification or attenuation of the effect signal.

Below are some things to keep in mind when you are working with the Convolution algorithm:

•	If you want the impulse response sample to play back exactly like the original, make sure the Decay knob is at max, the LF Damp knob at zero and the Hi EQ knob at its 12 o’clock position. Also, make sure the Length parameter is at 100% and the Size parameter at 0.

•	The Length value of the impulse response sample is also affected by the Decay knob setting.

If the impulse response sample is quiet at the end, reduce the Length value to cut it off a little earlier. The Decay parameter introduces a smoother “cutoff” at the end, which might be desirable in many situations.

•

Changing some convolution parameters re-calculates the impulse response in real time. Therefore, modulating these parameters might give unexpected results. Specifically: Using CV to modulate the RV7000 Mk II in Convolution mode is not recommended. If you're using the Gate function (see “The Gate section”) in combination with Convolution, we recommend setting the Decay Mod parameter to 0 (see “Decay Mod”).

Loading impulse response samples

Besides the preset impulse response samples, you can load any other samples into the RV7000 Mk II and use as impulse responses. Loading a sample automatically switches the Algorithm to Convolution.

Drag and drop a sample onto the RV7000 Mk II panel to automatically load it in the Convolution Algorithm.

Or, do as follows:

1.	Click the Browse Samples button on the Programmer panel to set browse focus to the RV7000 Mk II.

2.	Select the desired sample in the Browser and load it.

Here we have selected and loaded the “Fx_DubHead.WAV” sample to use as impulse response. You can see that the sample name is now displayed to the right of the Preset knob.

Note that the maximum length of a sample used as an impulse response is approximately 12 seconds. Longer samples are automatically truncated to 12 seconds (non-destructive).

Note that any embedded loop data in the samples are disregarded when loaded into the RV7000 Mk II!

Note that the Programmer display only shows the first 4 seconds of longer samples.

To achieve stereo effects in the Stereo Mode alternatives (see “Stereo Mode”) you have to use stereo samples.

3.	Edit the Convolution parameters on the RV7000 Mk II panel until you are satisfied.

If you want to save your RV7000 Mk II patch with your impulse response sample, click the Save Patch button on the upper panel:

Note that the impulse response sample is NOT saved in the patch itself - only a reference to the sample! If you have loaded an external sample (that is not in the Factory Soundbank), you may want to save the patch with the sample in your song. See “About Self-Contained Songs”.

Sampling your own impulse response samples

You can also sample your own impulse response samples and use with the Convolution algorithm. The sampling procedure is the same as for any other sampler device in Reason:

Click the “Start sampling” button on the Programmer panel to record your own sample:

Note that the maximum length of a sample used as an impulse response is approximately 12 seconds. Longer samples are automatically truncated to 12 seconds (non-destructive).

Note that any embedded loop data in the samples are disregarded in the RV7000 Mk II!

Note that the Programmer display only shows the first 4 seconds of longer samples.

To achieve stereo effects in the Stereo Mode alternatives (see “Stereo Mode”) you have to sample in stereo.

Please refer to the “Sampling” chapter for details on how to set up and sample in Reason.