Behringer System 15 Setup Checklist: 15-Inch Speakers, Power Amp, and Desktop Mixer

Who this checklist is for

I'm a quality and brand compliance manager at a pro-audio company. I review around 200 systems a year before they go to customers, and I've rejected my share of first deliveries for reasons that had nothing to do with the speakers. Usually the problem was in how the speaker, amp, and mixer were matched.

If someone writes 'behringer system 15' on an order form, I treat it as an incomplete spec. Usually they mean two 15-inch Behringer speakers, an external power amplifier, and a desk audio mixer. That is a system, but the exact models still need to be checked. This checklist is for that setup: two passive 15-inch PA speakers, one amplifier, and a mixer for a small venue, rental rig, or house of worship.

I'm not an acoustician, so I'm not going to tell you how to tune a room or design a delay system. I can tell you what to inspect before you turn things up. This should take about 20 minutes.

Step 1: Confirm whether each 15-inch speaker is active or passive

The first quality check is not a spec sheet. It's the back of the speaker. A powered speaker has a built-in amplifier and a line-level input. A passive speaker needs an external power amplifier connected to its speaker input.

In the current Behringer Eurolive range, the B115D is active and the B115W is passive. When a customer asks for 'behringer speakers 15 inch,' I check which one they actually need before recommending an amplifier. If you order an active speaker and a separate power amp, you have an extra amp. If you order a passive speaker and no power amp, nothing makes sound. That sounds basic, but it's the most common spec mistake I see on purchase orders.

Step 2: Match the amplifier to continuous power, not peak power

Every 15-inch PA speaker has at least three wattage numbers: continuous, program, and peak. The number that gets printed biggest on the box is usually the peak number. Do not size the amplifier with that number as your first reference.

I only believed this after ignoring it. Early in my career I pulled an amp out of stock because its peak power matched the speaker's peak rating. On the first real show, the amp was clipping when the volume got serious. The speaker voice coil survived the night but sounded rough afterward. Re-coning it cost more than the difference between that amp and the correct one. Now I start from the continuous rating.

If the speaker's spec sheet includes an AES continuous power rating, use that figure. The rule of thumb I use: the amplifier's continuous watts per channel at the speaker's impedance should be roughly equal to the speaker's continuous rating, and no more than about twice that rating. If a speaker is rated for 250 W continuous at 8 ohms, an amp producing 250 to 500 W continuous at 8 ohms is a sensible target.

This also applies when the amplifier is already in the building. I once opened a rack and found a Crestron power amplifier driving a pair of passive 15-inch speakers. The amp was fine, but the installer had set it for the wrong output mode, which leads to step 3.

Step 3: Check whether the amplifier is in low-impedance or 70V/100V mode

Commercial power amplifiers often support both low-impedance speakers and 70V/100V distributed audio. A standard 15-inch PA cabinet without an internal 70V transformer is a low-impedance speaker, usually 8 ohms. If the amp is left in 70V mode, the system can sound quiet, thin, or wrong, and the blame usually lands on the speaker.

In a school gym system I checked last year, the Behringer cabinets were fine, the mixer was fine, and the failing piece was a Crestron power amplifier that had been set to 70V. Once it was switched to low-Z mode, the system worked. So before you swap speakers or buy more power, verify the output mode on the amp and make sure it matches the speaker type.

Step 4: Set the desk audio mixer level before you touch the amp

The desk audio mixer in a small PA system is usually the control center, and the gain structure mistakes happen between the mixer output and the amp input. A good starting order:

1. Turn the amplifier input level down.
2. Power up the mixer first, then the amp.
3. Set the mixer main output fader around unity, not at maximum.
4. Set channel trims so the mixer meters sit around zero during normal talking or playing.
5. Raise the amplifier input levels slowly until the room reaches the volume you need.

If the mixer master is maxed out and the amp input is barely open, the signal path is out of balance. You get more noise and less headroom. You should not need to run every output and input at full scale.

Step 5: Use speaker cable between the power amp and the speakers

This one sounds too obvious to include, but in our Q1 2024 audit, cable and connector problems were the biggest single cause of first-test failures returned to us. A microphone cable can accidentally fit into some speaker outputs, especially in a dark rack. That doesn't mean it's a speaker cable.

From amplifier to passive speakers, use actual loudspeaker cable with SpeakON connectors or heavy-gauge speaker wire, not an XLR mic cable. Use appropriate gauge for the run length. Label both ends of the cable after you connect them, so the next person doesn't unplug the only working cable in the system.

Step 6: Put the mixer somewhere stable and reachable

The physical setup gets less attention than the electronics, but it causes just as many problems. A small desk audio mixer placed on a folding table can get bumped or pulled by the weight of the cables hanging out of the back. If you are using an audio mixer table stand, check that the stand is rated for the mixer weight and that all locking knobs are tight.

If you ask me, the mixer position is part of the sound check. If you can't see the stage from the mixer, you're mixing blind. If you have to reach over the table and hold one hand on the faders while supporting yourself with the other, you're going to bump something. Put the mixer where the operator can sit or stand comfortably, and run the cables so they don't pull on the rear connectors.

Step 7: Do a 'quiet to show level' test, then mark the settings

Before the show, I want to find problems at low volume first. The sequence looks simple, but it catches a lot of bad installations:

1. Start with the amp input level at zero and the mixer main fader down.
2. Turn the mixer on first, then the amplifier. This order avoids thumps from source devices powering up through the amp.
3. Send music or voice through the mixer at a normal level and watch the mixer meters.
4. Slowly raise the amp input until the room is at the intended show level.
5. Walk to each speaker and listen for clear highs, clear lows, and no buzzing or distortion.
6. If the amp clip LED flashes on every loud note, back the amp input off a little. Don't push it into continuous limiting.
7. Once the level is right, put a small piece of tape on the amp level knob and write down the mixer main setting. That becomes the baseline for the next operator.

Mistakes I still run into

• Using peak watts to match amps to speakers. This is still common, especially on smaller budgets. The peak number is for marketing; the continuous number is for engineering.
• Leaving a commercial amp in 70V mode. If the amplifier can do both low-Z and 70V/100V, verify the switch or menu setting before connecting standard PA cabinets.
• Trying to fix a setup problem with EQ. If the system sounds thin, don't reach for the mixer EQ first. Check the amp mode, the gain structure, and the cables. EQ can mask a problem, but it won't fix the root cause.

One more practical thought. In my experience, small purchases shouldn't get less care. We run the same quality check on a two-speaker starter PA as on a larger install. Not because today's order is huge, but because the person putting together a Behringer system 15 this month might be putting together a full stage next year. If they get reliable gear and a setup that makes sense, they'll be back.

If your project is a complex distributed system with ceiling speakers or a flown line array, this is not the right checklist, so don't stop at step 7. For a straightforward 15-inch speaker system with an amp and a desk mixer, though, these checks have saved me a ton of trouble.