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Loudspeakers and amplification

12 Inch vs 15 Inch Speakers for a Church

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Quick answer

A 15 inch woofer buys low frequency extension, not loudness, so the rule is simple: choose 15 inch mains only if no subwoofer will ever be bought. With a subwoofer in the system, a high-passed 12 inch main is cleaner and is what most installed church systems use.

Woofer size is the most misunderstood specification in church audio, so here is the short version: a 15 inch driver does not make a speaker louder, it makes it go lower. Both cabinets above run the same amplifier and the same 90 by 60 horn, so every difference between them is in the bottom two octaves.

That turns the decision into a single question about your budget rather than your room. If a subwoofer is in the plan, buy 12 inch mains and high-pass them. If a subwoofer is never going to be approved, buy 15 inch mains and accept that they are doing a job they were not really designed for. Check what your service style needs on the subwoofer sizing calculator.

The same cabinet in two woofer sizes

A 12 inch and a 15 inch version of the same loudspeaker
Model Price PoweredPeak powerWooferCoverage patternPole mountOnboard DSP
Electro-Voice ZLX-12P-G2 12in. 2-Way Powered Loudspeaker with Bluetooth Electro-Voice ZLX-12P-G2 12in. 2-Way Powered Loudspeaker with Bluetooth $549.00 Yes1,000 W12 in90 by 60 degreesYesYes
Electro-Voice ZLX-15P-G2 15in. 2-Way Powered Loudspeaker with Bluetooth Electro-Voice ZLX-15P-G2 15in. 2-Way Powered Loudspeaker with Bluetooth $649.00 Yes1,000 W15 in90 by 60 degreesYesYes

What each size is good and bad at

Cone area helps at the bottom and hurts in the middle. Both effects are real and both matter in a church.

A 15 inch cone extends usable output roughly half an octave lower, at the cost of midrange directivity that a church room needs for speech.

Twelve inch against fifteen inch in a sanctuary
Property12 inch15 inchConsequence in a church
Low frequency extensionLessMoreBass guitar and kick weight
Midrange directivityTidierBeams earlierSpeech clarity off-axis
Cabinet weightLighterHeavierVolunteer handling on stands
Cabinet sizeSmallerLargerVisual impact in a sanctuary
Maximum levelSimilarSimilarSame amplifier, so no gain
Price$549.00$649.00About $100 per box

Beaming means a larger cone narrows its coverage at higher frequencies, so listeners off to the side hear a duller sound. In a wide church room that is a real cost.

Choose 12 inch mains for installed systems and with a subwoofer

The standard, well-designed church system is 12 inch mains high-passed around 100 Hz with a subwoofer underneath. That arrangement gives the mains an easy job, keeps their midrange directivity tidy for speech, and puts the low frequency work in a cabinet built for it. It also lets the subwoofer sit where low end works best in the room, which is rarely where the mains hang.

Twelve inch cabinets are lighter, smaller and less visually intrusive, which matters in a sanctuary where the building committee has opinions about what is visible. And they are the correct choice for every fill position: front fills, under-balcony fills and side fills all need clarity rather than weight.

If you want the low end and cannot fit a subwoofer under the platform, look at a compact model such as the KS112, which is built to fit where an 18 inch cabinet will not.

Choose 15 inch mains when there will never be a subwoofer

Many churches will genuinely never approve a subwoofer line, and pretending otherwise leads to a system with no low end at all. For a blended or contemporary service in that position, a 15 inch main is the honest answer: it puts bass guitar and kick drum into the room with some weight, from one box per side, with no extra amplifier or crossover to manage.

It is also right for a single-box-per-side situation: a fellowship hall, a youth room, a portable setup or an outdoor service where there is nothing else reinforcing the bottom end.

Handle the weight seriously. A 15 inch powered cabinet on a stand at head height near a congregation needs a stand rated well above the cabinet weight, such as a TeleLock pair, with the height locked properly rather than resting on a pin.

Sources

  • Electro-Voice published ZLX G2 series specifications
  • Loudspeaker directivity and cone diameter principles

Frequently asked questions

Does a 15 inch speaker cover more seats?

No, and often slightly fewer. Coverage is set by the horn pattern, and both of these cabinets use the same 90 by 60 waveguide. The larger cone actually narrows its own coverage at upper frequencies, so listeners sitting well off to the side hear a duller sound from a 15 than from a 12.

What crossover frequency should I use with a subwoofer?

Around 80 to 100 Hz for 12 inch mains is the usual starting point, set on the subwoofer or in a system processor rather than left to chance. High-passing the mains is the important half: it stops them wasting amplifier power on frequencies the subwoofer is already producing much better.

Is a 15 inch better for a gymnasium or fellowship hall?

Often yes, because these are single-system rooms where no subwoofer is coming and the content is mixed. A hall with a hard floor and hard walls will also hold onto low frequency energy, so do not overdo it. Start with the low end set conservatively and raise it only if the room stays clear.

Can I use 15 inch mains and add a subwoofer later?

Yes, and it works fine. When the subwoofer arrives, high-pass the 15 inch mains just as you would 12s. You will not get the tidier midrange of a 12, but you gain all the other benefits of a dedicated low frequency cabinet. Nothing is wasted by starting with 15s.

What about 10 inch or 8 inch cabinets?

Those are fill and small-room speakers. An 8 inch box with a wide pattern is ideal as a front fill for the first two pews or as an overflow room speaker, where clarity matters and level does not. They are not main loudspeakers for a sanctuary and should not be sold to you as such.

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.