This version (16 Jan 2020 17:30) was approved by KenM.The Previously approved version (24 Jul 2012 20:41) is available.
Table of Contents
Speaker Response: MLSSA
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The Speaker Response algorithm uses the MLSSA (maximum-length-sequence system analyzer, an industry standard) loudspeaker measurement system (www.mlssa.com). To employ this block:
- Drag it into the workspace.
- Click the text area.
- Select the appropriate file and load your speaker data.
This speaker response cell serves as an informational tool only. It does not have any intelligence that attempts to correct for the frequency response of the speaker. It is up to the user to tune the frequency response as needed.
MLSSA File Format
Note: Speaker files are ASCII text in the MLSSA format, with header information in quotes on the first two lines. Data are delimited by commas and by line. Note: SigmaStudio only accepts the MLSSA file if the 2nd line in the header of the matches the following exactly: <6 white spaces> “Hz” <2 white spaces> “Mag (dB)” <7 white spaces> “deg” <New line>. If not, the following message will be shown: Text file does not contain valid speaker data or file is Read Only
Here is an excerpt from an example MLSSA file:
30 deg OFF Axis Speaker.txt "Sensitivity Excess Phase - dB SPL/watt (8 ohms, @0.50 meters) (High)" "Hz" "Mag (dB)" "deg" 18.42571, 84.52863, -84.71303 27.63856, 86.17458, -106.1154 36.85141, 87.69691, -121.8004 46.06427, 89.03174, -131.5714 55.27712, 90.10346, -139.7477 64.48997, 91.02969, -145.4236 73.70283, 91.75486, -150.4895 82.91568, 92.44266, -154.1127 92.12853, 92.89854, -156.9609 101.3414, 93.26881, -159.7996 110.5542, 93.58502, -162.1092 128.9799, 93.96911, -166.0203 138.1928, 94.03343, -167.4651 156.6185, 94.05841, -170.1367 184.2571, 93.83049, -173.6306 202.6828, 93.62083, -175.2098 221.1085, 93.41589, -177.1104 248.747, 93.20612, -179.7584 276.3856, 93.04501, 178.67 313.237, 92.84193, 175.7724 ... ...
Example MLSSA Files Bundled with SigmaStudio
Example MLSSA files can be found in the SigmaStudio install directory's Speaker Measurements subfolder.
Viewing MLSSA Response
After adding an MLSSA cell to the project and selecting a response file, the response can be viewed using the Stimulus/Probe blocks.
By clicking on the probe button and then the stimulus button, the response will be displayed.
Correcting the Speaker Response
To attempt to correct the speaker response, insert filters in the signal flow between the stimulus and probe, and tune them to attempt to create the desired frequency response.
The result of this basic 3-band EQ on the 30 degree off-axis speaker response is shown here:
resources/tools-software/sigmastudio/toolbox/systemschematicdesign/speakerresponsemlssa.txt · Last modified: 12 Jun 2019 07:57 by Ruben Bjerregaard