How Sunship Audio Measures Loudspeaker Performance
A loudspeaker specification becomes useful only when it explains how a system behaves in a real room and at realistic listening levels. At Sunship Audio, measurement is therefore treated as a design tool rather than a marketing exercise. Frequency response, acoustic phase, distortion, sensitivity, and dynamic compression each reveal a different part of the loudspeaker’s performance.
Our custom horn-loaded systems combine TAD-Pioneer compression drivers and woofers with bi-radial wooden horns, time-aligned passive crossovers, and heavily braced birch plywood cabinets. These elements are designed as one acoustic system, so they must be measured together. The goal is a loudspeaker that remains coherent, expressive, and controlled across the full audible range.
Measurements help us identify resonances, crossover irregularities, cabinet vibration, and driver limitations. They also give us a reliable basis for listening tests, where tonal balance, spatial scale, transient clarity, and natural dynamics can be judged with confidence.
Frequency Response As A Design Map
Frequency response shows how evenly a loudspeaker produces sound across frequency. It can reveal a rising treble, a recessed presence region, bass roll-off, horn coloration, or a crossover mismatch that may otherwise be mistaken for a characteristic of the recording. We examine the response at different output levels and listening angles because a single on-axis trace does not describe the entire listening experience.
Horn geometry has a major influence on directivity. A bi-radial wooden horn is intended to control horizontal and vertical dispersion in a predictable manner, helping the loudspeaker maintain a stable tonal balance across the listening area. Measurements away from the central axis show whether energy remains consistent as the listener moves, while nearfield and farfield measurements help separate low-frequency cabinet behavior from room effects.
Low-frequency response is assessed with techniques suited to the physical size of the cabinet and the listening environment. Higher frequencies can be measured with time-windowed techniques that reduce reflections, while bass measurements may combine nearfield data, gated measurements, and listening-room verification. The resulting response is interpreted as a complete acoustic picture rather than reduced to one idealized curve.
Phase And Time Alignment
Amplitude tells us how much sound is produced; phase tells us when different parts of that sound arrive. Around the crossover region, phase behavior is especially important because the woofer and compression driver must combine smoothly. If their acoustic outputs arrive with the wrong timing or polarity, cancellations can create uneven response and a less focused image.
Sunship Audio uses time-aligned passive crossover networks to coordinate the drivers acoustically. This does not mean chasing a visually perfect phase plot at the expense of musical performance. Instead, we examine impulse response, excess phase, group delay, and the relationship between acoustic centers to understand whether the system behaves as a coherent source.
A well-integrated system can produce sharper image placement, more intelligible vocals, and cleaner transient edges. Percussion attacks, plucked strings, and the leading edge of a piano note are particularly revealing. Phase measurements help establish the technical conditions for these qualities, while listening confirms whether the timing relationship remains convincing with real music.
Distortion At Realistic Levels
Distortion is any unwanted alteration added to the original signal. Harmonic distortion creates additional tones related to the fundamental, while intermodulation distortion produces unwanted products when several frequencies are reproduced together. Both can affect clarity, texture, and the sense of ease, particularly at high sound pressure levels.
We measure total harmonic distortion across frequency and output level, paying close attention to the crossover region, bass frequencies, and the operating range of the compression driver. A distortion figure at a low test level may look impressive while saying little about performance during a demanding orchestral peak. For that reason, we repeat tests at levels that reflect serious listening and examine how distortion changes as the system works harder.
Horn loading can provide high acoustic efficiency and substantial dynamic headroom, but it does not remove the need for careful driver integration. The motor structure, diaphragm behavior, crossover slope, cabinet rigidity, and horn profile all contribute to the final result. Heavy birch plywood bracing helps reduce enclosure radiation, allowing measurements to reflect the intended drivers and acoustic loads rather than audible panel vibration.
Reading The Measurements Together
No individual graph can define a loudspeaker. A smooth frequency response with poor directivity may sound inconsistent around a room. Low distortion with unstable phase may produce a presentation that feels disconnected. Excellent sensitivity does not automatically guarantee accurate tonal balance. Performance must be assessed through several related measurements.
| Measurement | What It Reveals | Why It Matters |
|---|---|---|
| Frequency response | Tonal balance and crossover integration | Shows whether the system is even and consistent |
| Off-axis response | Dispersion and power response | Indicates how sound changes around the listening position |
| Impulse and phase response | Driver timing and acoustic alignment | Helps preserve transient coherence and image focus |
| Harmonic distortion | Added overtones at different levels | Identifies strain, resonance, or driver nonlinearity |
| Intermodulation distortion | Interaction between simultaneous tones | Relates to congestion and loss of clarity |
| Compression testing | Output stability as level rises | Shows whether dynamics remain open during peaks |
We also compare data collected before and after crossover adjustments, damping changes, and cabinet refinements. This makes the design process traceable. If a change improves the response but introduces a new resonance or reduces usable output, the measurement record exposes that trade-off before the system reaches final assembly.
From Laboratory Data To Listening
Measurement microphones and analyzers are precise, but they cannot replace informed listening. The ear responds to patterns that may be difficult to summarize with one metric, including the character of decay, the sense of scale, and the way a loudspeaker handles complex musical passages. We use familiar recordings to check whether measured improvements translate into greater naturalness and involvement.
Listening takes place at controlled levels and from known positions, then across a wider range of recordings. Voices reveal midrange balance and phase coherence; acoustic instruments expose timbral color; dense mixes test intermodulation behavior; bass-rich material reveals cabinet control and low-frequency integration. Repeated comparisons help distinguish a genuine improvement from the excitement of a louder presentation.
Visitors can hear how the measurements connect with musical results in the Berlin listening room, where complete systems are demonstrated in a carefully prepared environment. The room cannot represent every domestic space, but it provides a consistent reference for assessing directivity, scale, dynamics, and tonal character.
A Practical Measurement Priorities
For a custom loudspeaker, the most useful measurement program is one that reflects both engineering objectives and intended use. We prioritize data that can guide component selection, cabinet construction, crossover voicing, and final placement rather than collecting specifications without a clear purpose.
The following priorities keep the evaluation focused:
- Measure on-axis and off-axis response to understand tonal balance and dispersion.
- Check phase, impulse response, and crossover summation for coherent driver integration.
- Test harmonic and intermodulation distortion at multiple sound pressure levels.
- Examine compression and thermal behavior during sustained high-output operation.
- Confirm laboratory findings with controlled listening using varied music.
Built Around Verifiable Performance
Sunship Audio measures performance to understand why a loudspeaker sounds the way it does. Frequency response establishes tonal accuracy, phase analysis clarifies timing, and distortion testing shows how cleanly the system handles demanding signals. Cabinet construction, horn loading, driver selection, and passive crossover design then work together to support those results.
A custom loudspeaker should be evaluated as a complete instrument, from its acoustic output to its behavior in a room. Contact Sunship Audio to discuss a system built around your space, listening priorities, and the measured performance that matters most.