Beocreate 2 integrates with Beocreate 4-Channel Amplifier, which contains a flexible and powerful DSP (digital signal processor) for customising the sound signature of the system.
Speaker presets are collections of sound adjustment settings that can be applied at once, instantly. Presets can be imported right in the user interface (Sound > Speaker Preset > Import Preset). In this document we cover how the presets work and how they can be created.
In Beocreate 2, speaker presets (previously called sound profiles) are now separated from DSP programs for greater flexibility:
- A DSP program determines the sound processing flow and which sound adjustment features are available.
- A sound preset contains the actual settings that are dynamically applied to the DSP program (equaliser and crossover parameters, levels, delays, ...).
In essence, speaker presets are JSON files. The following is an example of a valid, although nonsensical, speaker preset file:
{
"speaker-preset": {
"presetName": "Beovox CX 50",
"productIdentity": "beovox-cx50",
"fallbackDSP": "beocreate-universal",
"samplingRate": 48000
},
"equaliser": {
"a": [{"type": "highPass", "frequency": 1000}],
"b": [{"type": "peak", "frequency": 1000, "Q": 0.7, "gain": 2}],
"c": [{"type": "highShelf", "frequency": 1000, "Q": 0.5}],
"d": [{"b0": 0.933897197830, "b1": -1.247919091952, "b2": 0.678131896299, "a1": -1.366776677313, "a2": 0.731535942794}]
},
"channels": {
"a": {
"level": 100,
"enabled": true,
"role": "mono"
},
"b": {
"level": 100,
"enabled": true,
"role": "left",
"delay": 3
},
"c": {
"level": 80,
"enabled": true,
"role": "side"
},
"d": {
"enabled": false
}
}
}
The file has been divided into three top-level items: speaker-preset, equaliser and channels. Each of these correspond to different extensions in Beocreate 2, which will handle the settings when previewing and applying the preset.
Note: These settings are currently supported by the default Beocreate 2 extensions and Beocreate Universal DSP program. Other extensions and DSP programs can add support for more settings.
Presets have two different names:
- file name: used in the file system, always unique
- preset name: the visible, "nice" name shown in the user interface
Both names are required. File names always need to be unique, because two files can't have the same name in the same folder. Whilst preset names do not have such a requirement, unique names are recommended to tell presets apart in the user interface.
Preset name should be embedded in the sound-preset section of the file as presetName property, such as in the example.
Next, we will cover the different sections and possible settings of a preset in detail. Required settings in each section are indicated as such, others are optional.
This is the only required section. It stores basic information about the speaker preset, listed below.
"presetName": "Beovox CX 50"
Required. The name of the preset shown in the user interface.
"productIdentity": "beovox-cx50"
The identifier of a "product identity", that may contain information such as model name, manufacturer, designer, manufacturing years and a product image. Several product identities are included in Beocreate 2. Define this property to use a standalone product identity or an identity from another speaker preset.
For more information on product identities, refer to this document.
"fallbackDSP": "beocreate-universal"
If the current DSP program doesn't support all of the settings in the preset, install the DSP program with this file name, if it is available on the system. For all default speaker presets, this is "beocreate-universal". Other presets can use it as well if suitable.
"samplingRate": 48000
Required in some cases. The value is in Hz.
If the speaker preset contains filters defined as coefficients directly (explained later), the sampling rate has to be defined so that it can be matched with the DSP program. If not defined, those filters may not sound the way as intended. The sampling rate can also be defined with each filter, but this is an easier way.
"presetVersion": 1
Integer version number of the preset. For future use.
Settings for the parametric equaliser in the DSP program, intended for correcting the loudspeaker's magnitude response. This section is further subdivided into up to four channels as follows:
"equaliser": {
"a": [],
"b": [],
"c": [],
"d": []
}
Note: each channel is an array, not an object.
Channels A-D correspond to the speaker terminals on Beocreate 4-Channel Amplifier from left to right, when the terminals are facing you.
Within each channel the individual filters and their parameters can be defined. The amount of filters is limited by the DSP program. For example, Beocreate Universal supports up to 16 filters per channel. If the number of filters supported is less than is defined, the overflowing filters are ignored.
Leaving channels blank like above will bypass all of the filters on the channels. If a channel is not included, its settings will not be altered when the preset is applied. This is not recommended, as it might cause an undesired mix of settings – it is always better to bypass the filters on a channel.
The following filter types are supported:
- peak/dip
- high/low pass
- high/low shelf
- coefficients
You can find in-depth explanations for the different filter types here. They can be mixed and matched in any combination to shape the sound as desired.
{"type": "peak", "frequency": 1000, "Q": 0.7, "gain": 2}
A peak or dip filter either amplifies or attenuates sound at and around the centre frequency. Note: in both cases, the filter type is specified as peak.
- frequency: centre frequency of the filter in Hz. Required.
- Q: the "sharpness" of the filter – the higher the value, the narrower the bandwidth of the filter. Required.
- gain: the amplification (positive value) or attenuation (negative value) of the filter in dB. Required.
If all of these parameters aren't defined, the filter will be bypassed. The filter is a single-precision, 2nd-order filter.
{"type": "highPass", "frequency": 1000}
Cuts sound above (lowPass) or below (highPass) the cutoff frequency, letting others pass. Ideal for creating simple crossovers.
- frequency: cutoff frequency of the filter in Hz. Required.
- Q: by default the filter is a 2nd-order Butterwork filter (12 dB/octave). Define Q to customise the filter.
Tip: you can create steeper filters by adding (cascading) more high-pass or low-pass filters to the same channel. For example, to achieve a 4th-order Linkwitz-Riley (24 dB/octave) filter, add two filters with the default Q at the same frequency.
{"type": "lowShelf", "frequency": 1000, "Q": 0.7, "gain": 2}
Boosts or attenuates sound above (highShelf) or below (lowShelf) the centre frequency. For example, the ToneTouch feature uses high and low shelf filters to adjust bass and treble.
- frequency: centre frequency of the filter in Hz. Required.
- Q: the "sharpness" of the filter – the higher the value, the steeper the "edge" of the shelf. Required.
- gain: the amplification (positive value) or attenuation (negative value) of the filter in dB. Required.
If all of these parameters aren't defined, the filter will be bypassed.
{"b0": 0.933897197830,
"b1": -1.247919091952,
"b2": 0.678131896299,
"a1": -1.366776677313,
"a2": 0.731535942794,
"samplingRate": 48000}
For advanced, entirely custom filters, the filter coefficients can be defined directly.
The required parameters are the coefficients: b0, b1, b2, a1, a2. The system assumes a0 to be 1 and thus it can't be defined.
The coefficients have to be calculated against the sampling rate of the DSP program (48 kHz for Beocreate Universal). The sampling rate these filters are intended for should be indicated in the sound-preset section (see earlier) or with each filter, next to the coefficients (such as here).
A missing sampling rate is not fatal, but the filter may sound different than expected. A warning will display in Speaker Equaliser interface.
Contains other sound settings related to each loudspeaker channel. This section is further subdivided into up to four channels as follows:
"channels": {
"a": {},
"b": {},
"c": {},
"d": {}
}
Note: each channel is an object, unlike in the equaliser section.
Channels A-D correspond to the speaker terminals on Beocreate 4-Channel Amplifier from left to right, when the terminals are facing you.
Within each channel, certain settings can be defined. Any settings that are not defined will not be altered when the preset is applied. It is recommended to always define settings that need to be consistent and known.
The following settings are supported for each channel:
- Mute/unmute (enabled)
- Role
- Level
- Delay
- Invert polarity
A simple "is this channel playing" setting. If set to false, the level setting will have no effect.
"enabled": true
Possible values are: true or false.
Defines the signal played by the channel.
"role": "left"
The possible roles are determined by the DSP program. Beocreate Universal supports:
- left
- right
- mono (left added to right)
- side (right substracted from left)
Volume of this channel relative to the input signal.
"level": -1.3
The level can be defined as:
- integer volume level in the range of 1–100
- attenuation in dB, like in the example. 0 is full volume.
Tip: for best sound quality, level should be set to 0 or 100 (full volume) unless some channels need to be quieter than others. In this case, only attenuate the channels that need it.
Note: this setting does not override the master volume and volume limit settings available in the user interface, but is applied in addition to them.
For time-aligning loudspeaker drivers, delays can be specified for each channel.
"delay": 3
Delays are defined in milliseconds. You can use non-integer values for more precision.
Internally, the system converts the specified milliseconds to number of samples based on the current sampling rate, rounding the amount of samples to the nearest integer.
The maximum delay times are defined by the DSP program. For Beocreate Universal, this is about 41.6 milliseconds (2000 samples at the 48 kHz sampling rate). If you define a value that exceeds the maximum delay time, the system will apply the maximum delay.
It is recommended to only delay the channels that require it.
For some crossover configurations (such as 2nd-order), it may be necessary to invert the polarity of a channel to avoid cancellation of sound at the crossover frequency.
"invert": false
Possible values are: true or false.
Tip: although it is recommended to always ensure proper polarity when wiring up the loudspeakers, this setting can be used to "fix" or test for incorrect polarity of a loudspeaker driver.
The purpose and structure of product identities are covered here. Product identities can be embedded in speaker presets by adding a product-information section and defining the same properties there:
"product-information": {
"modelID": "beovox-cx50",
"modelName": "Beovox CX 50",
...
}
The product identities in sound presets will be discovered and made available in the system, for the user to choose or even for other sound presets to use.