Here is a frequency response curve. It is flat from roughly 50 Hz to 20 kHz, sitting around 80 dB, with only small ripples along the way.
It looks excellent. It is also close to meaningless on its own, and any manufacturer can show you one.
This is worth understanding, because “frequency response: 45 Hz – 20 kHz” on a spec sheet is the single most quoted and least informative number in audio.
Why one curve is not enough
A single response curve describes what a microphone measures at one point, directly in front of the speaker, in one direction.
That is not what you hear. In any real room, what reaches your ears is the direct sound plus everything that left the speaker in other directions and bounced off the desk, walls, and ceiling first. In a typical nearfield setup the reflected energy is a substantial part of what you perceive as tone.
Those reflections come from the same speaker — but from the sound it radiated sideways, upwards, and behind. If the speaker sounds one way straight ahead and noticeably different at 40° off to the side, then the reflections arriving a millisecond later carry a different tonal balance than the direct sound. Your ear integrates the two, and the result is a speaker that measures flat and sounds wrong.
Two speakers with identical on-axis curves can sound completely different in the same room. The on-axis curve cannot distinguish them. That is the problem the spinorama exists to solve.
What a spinorama actually is
A spinorama is a standardised set of measurements taken all the way around a loudspeaker — a full sphere, at many angles horizontally and vertically — then condensed into a handful of curves on one chart. The standard is CTA-2034 (formerly ANSI/CTA-2034-A), and its value is that everyone computes it the same way, so charts from different sources are directly comparable.
Here is what each curve is:
- On-axis — the single curve from before. Now it is context, not the headline.
- Listening Window — an average over a small range of angles around the axis, roughly what you get when you are not sitting perfectly still. If this differs a lot from on-axis, the speaker demands you not move.
- Early Reflections — an estimate of the first bounces off floor, ceiling, side walls, front wall and rear wall. This is the sound arriving just after the direct sound.
- Sound Power — the total energy radiated in every direction. This drives the reverberant field of the room.
- Predicted In-Room — a weighted combination approximating what a measurement in a typical room would show.
- Directivity Index (DI) — read on the right-hand axis. It is the difference between the direct sound and the radiated energy: how focused the speaker is at each frequency.
The rule that matters: parallel beats flat
Most people look at a spinorama and hunt for the flattest line. That is the wrong instinct.
Every loudspeaker becomes more directional as frequency rises — it is physics, not a design failing. So Sound Power should fall away from On-axis as you move right across the chart. A speaker where all the curves stayed flat and stacked together would be a strange object, not a good one.
What you want is for the curves to separate smoothly and stay roughly parallel. Parallel curves mean the off-axis sound has the same tonal shape as the direct sound, just quieter. Reflections then sound like the speaker rather than like a different speaker, and the room adds level without adding colour.
What you do not want are sharp local features — a sudden dip or spike in one curve but not the others, or a place where DI lurches. Those usually mark a crossover where two drivers are interfering, and they are the kind of thing that follows you around the room.
In the chart above, On-axis, Listening Window and Early Reflections track each other closely up to about 1 kHz, then fan out gradually. The separation grows steadily rather than in steps. Both DI curves rise smoothly from near 0 dB in the bass to roughly 5–10 dB at the top of the band.
A feature in our own data, and how to judge it
Look at the DI curves around 10 kHz. There is a visible dip — directivity index drops, then climbs again above it. In plain terms, the speaker's coverage widens slightly in that region before narrowing again.
We are pointing at it because learning to read these charts means learning to interrogate them, including ours. So how do you judge a feature like that?
- Is it in the direct sound or only the radiation pattern? A wobble that appears in DI but leaves the Listening Window smooth affects the character of reflections more than the sound arriving straight at you.
- How wide is it? Narrow features are far less audible than broad tilts. A gentle 2 dB slope across three octaves is more consequential than a sharp 2 dB notch over a fraction of one.
- Is it a transition or a break? Curves that move smoothly through a region behave predictably as you move. A discontinuity means something is interfering.
- Where is it? 10 kHz is well above the range where our hearing is most discriminating, and above nearly all musical fundamentals.
Apply those four questions to any spinorama you are shown, including from brands with far more marketing budget than us. A published chart with a visible feature and an explanation is worth more than a chart that has been smoothed until nothing is visible at all.
Reading the early reflections chart
This breaks the reflections into the individual surfaces. It looks busier than it is.
The rear wall bounce falls away sharply above roughly 700 Hz. That is not a fault — a speaker that radiates forward should send progressively less energy backwards as frequency rises. If that curve tracked the others all the way up, the speaker would be spraying treble behind itself.
The floor, ceiling, side wall and front wall curves are the ones to study, because those reflections do arrive at you. What you want is for them to hold the same broad shape as the direct sound while dropping in level — the parallel rule again, applied surface by surface.
Where the data comes from
How a spinorama is captured matters as much as the fact that one exists.
The traditional method is gated far-field measurement: place the speaker in a large space, measure, and cut off the recording before room reflections arrive. It works, but the gate limits low-frequency resolution — the lower the frequency, the longer the wavelength, and eventually you run out of time before the reflection arrives.
Every MiniMax3 Monitor is characterised on a Klippel Near-Field Scanner instead. A robotic arm samples the sound field close to the speaker at many points and computes the full radiation pattern from that data, with the room's contribution mathematically removed. The result is full-sphere data that stays valid down into the bass, from a normal room rather than an anechoic chamber.
Our published set includes on-axis response, off-axis behaviour at 15°/30°/45°/60°, the CTA-2034 spinorama, early reflections, horizontal and vertical directivity, distortion at two levels, and every placement and tone-control setting measured individually.
Thirty seconds with any spinorama
When someone puts a chart in front of you:
- Do the curves stay roughly parallel as they separate? If yes, reflections will sound like the speaker. This matters more than flatness.
- Does DI rise smoothly, without lurching? Sudden movement usually means crossover interference.
- Is the Listening Window close to On-axis? If they diverge early, the speaker has a narrow sweet spot and you will feel it every time you shift in your chair.
Three questions. They will tell you more than any spec sheet line.
Verify it yourself
Manufacturer measurements should raise your eyebrow by default, ours included. The MiniMax3 Monitor has been independently measured and reviewed by Erin's Audio Corner, using his own Klippel scanner and his own methodology. We had no involvement in his measurements or his conclusions.
That is the standard worth holding any brand to: published data, in a comparable format, that somebody else can and did check.
MiniMax3 Monitor — the most compact 3-way coaxial desktop monitor. The full measurement set is on the product page.
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