Measurements and GLL / CLF Files: Overview

Excelsior Audio features a lab specifically for loudspeaker measurements. Our focus is on performing directivity balloon, sensitivity, maximum input voltage, and other measurements to characterize loudspeaker system performance. These measurements collect the primary data required for use in building loudspeaker modeling files (e.g. GLL and CLF), as well as for loudspeaker performance optimization.

Accurate, high-resolution directivity data are used to create GLL files for loudspeakers. This data meets the requirement of modeling and optimization programs such as EASE, EASE Evac, EASE Focus, and AFMG FIRmaker. CLF format files for other modeling programs can also be created from our measurement data.

The Excelsior Audio lab is positioned to fulfill almost any of your loudspeaker measurement and modeling needs. We are pleased to be one of only a handful of independent labs world-wide providing measurement and GLL/CLF authoring services.

If you are a loudspeaker manufacturer, sound system design consultant, design-build firm, or someone that needs objective measurement data for your loudspeakers please contact us.

Frequency Response / Impulse Response
The impulse response (IR) measurement is one of the most often measured characteristics of a loudspeaker. It is the time domain equivalent of the transfer function, often called the frequency response. The IR contains both magnitude and phase information (complex data). The on-axis IR can be used to determine the sensitivity of the loudspeaker. IR measurements at off-axis positions can be assembled to form the directivity balloon for a loudspeaker.
Frequency Response Frequency Response (magnitude and phase)
without FIR fitler and with FIR filter
Impulse Response Impulse Response
FIR Filter Development
Our on-axis and off-axis impulse response measurements can be used to develop FIR filters to help linearize the phase response and improve the transient response of loudspeaker systems.
Directivity Response (Directivity Balloon)
The directivity balloon is the 3D equivalent of a polar graph. It shows the radiation characteristics of the loudspeaker in three-dimensional space and has both magnitude and phase information (complex data). The directivity balloon is very useful in acoustical modeling programs to map the SPL (sound pressure level) from a loudspeaker on to the various surfaces of the room, as well as the audience areas. Directivity Balloon
Impedance Measurements
Impedance measurements are used to determine the rated impedance of your loudspeaker per industry standards. Our impedance measurements are also complex data, containing both magnitude and phase angle information.
Maximum Input Voltage Measurements
The maximum input voltage (MIV) of loudspeakers is determined according to industry standards. Maximum SPL calculations in modeling programs based on MIV correlate well with real world measurements of deployed systems. The MIV data can also be used to adjust limiter settings so that loudspeakers can reach maximum SPL while still sounding good and not being damaged.
Custom Measurements and Analysis
We can perform other loudspeaker measurements not usually performed to generate GLL or other loudspeaker modeling files. Contact us to discuss your needs.
Crossover Design and Optimization
Our crossover optimization service uses the directivity balloons of the individual pass band (e.g. LF, MF, and HF) to investigate the directivity of the loudspeaker system through the crossover region(s). The crossover design is optimized for good off-axis response in the crossover region(s) without having to re-measure the loudspeaker.

The graphs below show a comparison of the response, before and after the optimization process, for a two-way loudspeaker comprised of a 15 inch woofer and a high frequency horn. The result of the optimization is much more consistent vertical directivity through the crossover region from 1 kHz to 2 kHz. The on-axis response remains virtually unchanged.

Frequency Response On-Axis Frequency Response
Before Optimization (red)
After Optimization (blue)
Vertical Beamwidth Vertical Beamwidth
Before Optimization (red)
After Optimization (blue)
Vertical Directivity Map Vertical Directivity Map
Before Optimization
Vertical Directivity Map Vertical Directivity Map
After Optimization
Excelsior Audio (704) 675-5435 info @