Loudspeakers and amplification
Line Array vs Point Source for a Church
Quick answer
Room shape decides this. A column array suits long narrow rooms over about 60 feet deep because its level falls roughly 3 dB per doubling of distance instead of 6 dB. A point source suits wide, shallow rooms and costs far less to cover them.
QSC KC12-BK System Column Line Array PA
$1,999.99 Specs and sizingA column of small drivers over a 12 inch subwoofer, which holds level from the front pew to the back wall without flying anything from the structure.
Best for: Long narrow sanctuaries and historic buildings where nothing may be attached to the structure
Check price on Amazon
QSC K12.2 Active 12" Powered 2000 Watt Loudspeaker
$899.99 Specs and sizingA single 12 inch cabinet with a 75 degree conical pattern, which is the cheapest way to cover a normally proportioned sanctuary well.
Best for: A 150 to 400 seat sanctuary on stands or flown, for almost any service style
Check price on AmazonChoose by room shape, not by budget or by what the big church down the road installed. A column or line array controls vertical coverage, so it is the right tool for a long narrow room where the back row is a long way from the platform. A point source controls coverage in both planes from one box and covers a wide, shallow room far more efficiently.
These are different tools, and the failure mode of using the wrong one is specific. A column in a wide room leaves the outer seats dull and off-axis. A point source in a very deep room is either too loud at row three or too quiet at row thirty. Measure the room first and work it through on the speaker coverage calculator.
A column array and a point source side by side
| Model | Price | Powered | Woofer | Onboard DSP | Pole mount | Peak power | Max SPL |
|---|---|---|---|---|---|---|---|
| QSC KC12-BK System Column Line Array PA | $1,999.99 | Yes | 12 in | Yes | No | - | - |
| QSC K12.2 Active 12" Powered 2000 Watt Loudspeaker | $899.99 | Yes | 12 in | Yes | Yes | 2,000 W | 132 dB |
How level falls off in each
This is the whole physical argument. A point source obeys the inverse square law. A well-designed line array behaves more like a line source over part of its range.
A point source loses about 6 dB every time the distance doubles, while a line source loses closer to 3 dB, which is worth roughly 9 dB at the back of a 64 foot room.
| Distance from box | Point source | Line source behaviour | Difference |
|---|---|---|---|
| 8 ft | 0 dB reference | 0 dB reference | 0 dB |
| 16 ft | Minus 6 dB | Minus 3 dB | 3 dB |
| 32 ft | Minus 12 dB | Minus 6 dB | 6 dB |
| 64 ft | Minus 18 dB | Minus 9 dB | 9 dB |
| 128 ft | Minus 24 dB | Minus 12 dB | 12 dB |
Real column arrays only behave as a line source over part of their frequency range and within a transition distance set by array length. Treat this table as the direction of the effect, not as a specification.
Choose a column array for long, narrow and reverberant rooms
The classic case is a historic sanctuary: long, narrow, high ceilinged, hard surfaces everywhere and a reverberation time well over two seconds. A column array puts energy at the congregation and much less at the ceiling and the rear wall, which is exactly what a reverberant room needs. Less energy into the room means less reverberant return, which means speech stays intelligible. See reverberation time for churches.
The second case is a building where nothing may be attached to the structure. A column on a pole or a floor stand needs no rigging, no structural engineer and no holes in a protected interior, which in a listed or historic building can be the only permitted option.
The honest limits: columns are poor at wide horizontal coverage from a single position, they cost more per box, and they need a subwoofer to do anything musical. A contemporary band through columns alone will sound thin.
Choose point source for most ordinary sanctuaries
A room 60 feet wide and 50 feet deep with a 20 foot ceiling is covered well and cheaply by two or three point source boxes on the correct pattern. A 75 degree conical throws evenly to the back; the 90 degree K10.2 covers a wider, shallower room better. Choosing the pattern to match the seating shape is the whole skill, and it is what the placement guide covers.
Point source is also the more forgiving purchase. Boxes can be added as fills later, they work on stands or flown, every rental house has them, and a volunteer can understand where they are pointing. Coverage angle by model is in the coverage angle chart.
The limit is depth. Past roughly 80 feet a single point source position needs help, which is a delay fill rather than a bigger box. That is a design decision, not a product decision.
Sources
- QSC published K.2 and KC12 specifications
- Inverse square law and line source propagation principles
Frequently asked questions
Is a line array always better than a point source?
No. In a wide, shallow room a line array is the wrong tool and will sound worse than two well-chosen point source boxes at a fraction of the price. Line arrays solve a specific problem, which is holding level over a long throw while keeping energy off the ceiling. If you do not have that problem, do not buy that solution.
How deep does a room need to be to justify a column?
As a working threshold, past about 60 feet of throw with a reverberation time over roughly 1.8 seconds a column starts to earn its price. Below that, point source boxes plus a delay fill usually cover the room better for less money. Measure the throw to the back row before deciding.
Do column arrays need a subwoofer?
For a band, yes. The small drivers in a column cannot produce useful low frequency output, which is why systems like the KC12 are built on a 12 inch subwoofer in the base. For a speech-only traditional service, a column alone is often sufficient and the missing low end is not missed.
Can I use a column array outdoors?
Yes, and it is often a good choice because the narrow vertical pattern puts less energy into the sky and toward neighbours. Outdoors there is no reverberation to fight, so you are buying the pattern control for throw and for noise containment. Check weather rating before leaving anything outside overnight.
What about flying point source boxes instead?
Flying a point source higher and aiming it down is often the cheapest real fix for an uneven room, and it costs nothing but rigging. It must be engineered: rated hardware and a structural engineer or certified rigger signing off the attachment. Our guide on flying loudspeakers safely covers what that involves.
Researched, not professional advice. This page is compiled from published manufacturer specifications, operator manuals, FCC rules, published standards and owner-review consensus, not hands-on testing. Sound system design, rigging loudspeakers overhead, and any electrical work are jobs for a qualified professional: have flown loudspeakers and their attachment points signed off by a structural engineer or a certified rigger, and have all wiring done by a licensed electrician to your local code. Wireless microphone rules change, so confirm the current FCC position before buying. As an Amazon Associate we earn from qualifying purchases.