Professional hall sound: PA, delays, turnkey acoustics.
When the sound «wanders» across different seats — boomy bass here, the host’s voice dropping out there, audible stage echo elsewhere — the cause is almost never that the speakers are «weak» or «the wrong brand.» The cause is how sound waves interact with the room geometry: with modes, reflections, and boundaries. Per Harman research (Toole, Olive), below 300–500 Hz the placement of the source and listener relative to the walls gives a response spread of more than 18 dB, and between different rooms the divergence below 100 Hz reaches 25 dB. Against this, the difference between a «good» and an «excellent» amplifier in level-matched blind tests is less than 1 dB — the room error is an order of magnitude larger than the electronics error.
«Below 300–500 Hz the placement of the speaker and listener can cause response variations in the room of more than 18 dB — due to room resonances and the speaker’s proximity to its boundaries.»
Sean Olive, Harman research
In a concert hall and a club this physics is harsher than at home: distances are greater, there are several sources, and there are many zones with different geometry. So an even result is born not from a speaker’s spec, but from controlling where the system radiates energy and how the room works with it.
Before selecting equipment, we measure and calculate exactly these effects — each has clear physics and a predictable magnitude.
Below the transition frequency (~300–500 Hz) the room is ruled by standing waves. They produce peaks and dips of 18–25 dB: at one seat the bass «booms,» at the next it’s almost gone. No amplifier or DAC cures this.
Sound from the stage and its reflection from the floor, walls, and ceiling arrive at one point with an offset and add up into comb filtering — frequencies are alternately boosted and subtracted. Hence the «smeared» host’s voice and loss of intelligibility.
A speaker near a wall gives an interference null (Speaker Boundary Interference). Per Harman measurements the null depth is 6–25 dB (typically 12–20 dB). The dips settle into the 100–300 Hz zone when placed 0.3–0.9 m from the wall.
Above the transition frequency, intelligibility in a hall is set not by a speaker’s flat on-axis response but by how the system radiates energy into the space — its directivity and the ratio of direct to reflected sound. Control the dispersion and there are fewer reflections at the listener’s ears, so voice and music read more clearly at every seat. A verified precedent — cardioid speakers with controlled directivity (measured by Klippel/Stereophile): even coverage without smearing comes from the pattern shape, not from raising SPL.
Above the Schroeder frequency, dispersion control really does reduce the audibility of reflections and improve intelligibility. Less energy «into walls and ceiling» means more even coverage across the floor.
When the woofer is placed flush against the front wall, the speaker and wall merge into a single hemispherical source — this gives bass headroom and lifts the dip out of the working range. The wall becomes part of the system rather than something to fight. (Note: +6 dB is the half-space maximum; in a real hall it’s often closer to ~3 dB.)
Below the transition frequency directivity works weakly — there the modes rule, and they are treated with placement, distributed subwoofers, and targeted absorption. In our work, directivity and room treatment complement each other.
We run the project by measurement, not «by ear» — the only way to attack the room’s 18–25 dB errors that no electronics can cure.
Because evenness is determined not by power but by the interaction of sound with the space. Per Harman research (Toole, Olive), below 300–500 Hz placement and boundaries give a response spread of more than 18 dB, and between rooms below 100 Hz up to 25 dB. That’s tens of times larger than the difference between amplifiers. A loud system in an untreated hall simply excites the same modes and reflections more strongly. We treat the cause: we control directivity and treat the acoustics.
It’s control of where the system radiates energy. Above the transition frequency it is the ratio of direct to reflected sound that determines intelligibility, not a flat on-axis response. A verified precedent — cardioid speakers: controlled directivity around 4.8 dB (54 Hz–1 kHz), rear radiation at 200 Hz reduced by 10–15 dB (measured by Klippel). Less energy «into walls and ceiling» means more even coverage and a cleaner voice at every seat.
Because without a model of the space, selecting speakers is guesswork. The main errors in a hall are modes (peaks and dips of 18–25 dB), comb filtering from reflections, and SBIR nulls 6–25 dB deep. All of them are tied to the geometry and boundaries of the specific room. A 3D scan and impulse response give a map of these errors, and we design directivity, subwoofer placement, and treatment to that map. That makes the result predictable, not «however it turns out after installation.»
Yes, but not with one speaker and not with one EQ. Below the transition frequency the modes rule, and evenness comes from smart placement with distributed subwoofers plus targeted absorption that lowers the modes’ Q. Where appropriate we use boundary gain: a woofer flush against a wall merges with it into a single source and gives up to +6 dB of bass headroom (in a real hall often closer to ~3 dB). The goal is the same bass at different seats, not «loud at the stage and empty at the bar.»
Describe the venue — we’ll reply within 2 hours with a preliminary estimate and a measurement plan