Loudspeaker Response
Description
The Loudspeaker Response block evaluates the performance of a loudspeaker based on chirp measurements. The block calculates
the loudspeaker basic loudspeaker performance responses including: impulse reponse, frequency response, phase response, group delay response,
and THD response. You have the option of smoothing if desired.
Input
Reference Reference is the reference chirp inputted to the loudspeaker. The recommended reference signal is a loopback
of the outputted voltage. You can input N inputs with M length at once.
Signal signal is the measured chirp signal. You can input N inputs with M length at once for example if
you have repeated measurements.
Output
Impulse Response is the windowed impulse response with K samples according to the property Time to nearest reflection.
Frequency Response is the magnitude response of the windowed impulse response with desired number of FFT bins and Octave smoothing.
Phase Response is the phase response of the windowed impulse response.
Group delay is the group delay response of the windowed impulse response.
THD is the Total Harmonic Distortion response of the windowed impulse response, based on THD order number of harmonics.
System Delay is the total delay between 0 s and the time of the peak of the impulse.
Attributes
| Attribute | Value |
|---|---|
| Name | LoudspeakerImpulse |
| Pre-Peak time | 5 ms |
| Time to nearest reflection | ☐ 10 ms |
| Distance to nearest reflection | |
| FFT Bins | ☐ 16384 |
| Octave Smoothing | 1/12 |
| THD Order | ☐ 10 |
| Chirp Time | ☐ 4.5 s |
| Chirp Start Frequency | ☐ 20 Hz |
| Chirp End Frequency | ☐ 20,000 Hz |
| Inputs | 2 |
Values with ☐ can receive external input.
Name
Name specifies the name of the block.
Pre-Peak time
Pre-Peak time is a specified time that determines how much time you want to have before the peak of the impulse. To get the delay of the system look at the output System Delay
The Pre-Peak time is specified in order for you to get a consistent impulse length on every measurement.
Time to nearest reflection
Time to nearest reflection specifies the time delay between the direct impulse and the first reflection. If the time is higher than the delay of the first reflection then it will affect the evaluation of the loudspeaker performance.
Distance to nearest reflection
Distance to nearest reflection can be set instead of time to nearest reflection. The distance is the same as you would measure the length between the loudspeaker and a reflection object.
FFT Bins
FFT Bins is the desired resolution of the frequency responses. The number of FFT Bins must be higher than the number of samples K in the Impulse Response.
Octave Smoothing
Octave Smoothing is how much you want the frequency reponses smoothed. You can choose from 1/1 band octave smoothing to 1/48 band octave smoothing, or no smoothing at all.
THD Order
THD Order is the number of harmonics you want to calculate for the THD response. Default is up to the 10th order.
Chirp Time
Chirp time is the overall time of the reference chirp.
Chirp Start Frequency
Chirp start frequency specifies the start frequency of the reference chirp.
Chirp End Frequency
Chirp end frequency specifies the end frequency of the reference chirp.
Inputs
Inputs specifies the number of inputs the block requires. This cannot be changed.