Loudspeaker and electroacoustic testing
Anechoic measurement of what a transducer actually does, as opposed to what the datasheet says. Frequency response on and off axis, sensitivity, harmonic distortion, directivity and radiated sound power.
- Loudspeakers and drivers
- Public address and voice evacuation systems
- Alarms, sirens and warning devices
- AV products, soundbars and smart speakers
- Headphones and headsets
- Two-way radio and communications audio quality
- Speech transmission index to IEC 60268-16
Anechoic conditions are not a luxury here
A loudspeaker measured in an ordinary room is measured together with the room. Reflections from walls, floor and bench arrive milliseconds after the direct sound and add and cancel with it, producing peaks and dips in the response that belong to the room, not to the loudspeaker. At low frequencies, where the wavelengths are long and the reflections cannot be gated out in time, this is not a small correction.
This is why comparable loudspeaker data has to come from a qualified free-field environment. It is also why two published response curves for the same driver can look entirely different: not because either measurement was careless, but because one of them included a room.
What we can settle for you
- Whether a supplied driver matches the datasheet it was sold against — a question that comes up constantly in procurement disputes and is answerable in a single measurement session.
- Whether two production batches actually match each other, measured under identical conditions rather than compared across two suppliers' documents.
- Whether a design change did what it was supposed to do, measured before and after under the same conditions.
- What a system actually delivers at the listening position, as distinct from what the component specifications add up to on paper.
Distortion is where the marketing stops
Anyone can publish a frequency response. It is the easiest curve to make look good, and at low level almost every driver looks competent. Distortion at real operating level is a different matter, and it is the measurement that separates a genuinely well-made transducer from a specification sheet.
We measure total harmonic distortion and the individual harmonic orders across the frequency range and at stated drive levels. The level matters more than people expect: a driver that reads 0.3% THD at 1 W can be an order of magnitude worse at 10 W, and the point at which it turns is a design property, not a number you can interpolate. Reporting distortion without the drive level is the same category of error as reporting absorption without the mounting condition.
- Total harmonic distortion across the frequency range, at drive levels you specify.
- Individual harmonic orders — second and third order behave differently and point at different causes.
- Frequency response and sensitivity at 1 W, measured in the anechoic chamber rather than in a room.
- Directivity, so you know what the product does off-axis and not only in front of it.
- Batch-to-batch comparison under identical conditions, which is what a procurement dispute actually needs.