Monoblock Amplifier

What Is a Monoblock Amplifier

A monoblock amplifier (also written "mono block," and often shortened to "mono amp") is a single-channel amplifier that puts its entire output into one load. Two things separate it from a multi-channel amp asked to do the same job.

Power concentration. A 2-channel amp rated 500W per channel into 4 ohms makes 500W in each channel, separately. A monoblock rated 1000W makes 1000W into one channel. Subwoofers are usually wired to a 1 or 2 ohm load, and that is a high-current demand. The monoblock architecture delivers that current without splitting the power supply across channels that are doing nothing.

Low impedance stability. Most monoblocks are rated to 1 ohm, some to 0.5 ohm, which is what lets you wire dual voice coil subwoofers for maximum current draw. Most multi-channel amps are not 1-ohm stable per channel, so bridging one for sub duty caps what you can actually wire to it.

Monoblock or Bridged 2-Channel

Both drive a subwoofer. They are not equivalent, and the difference shows up at low impedance.

Bridging works. You give up impedance headroom and the channels you bridged. If the build has a dedicated sub and space for a second chassis, the monoblock is the better answer. If you are running a full active front stage, see the 4-channel and 6-channel amps instead, or the full amplifier lineup.

Matching a Monoblock to Your Subwoofer

Three specs decide the match: power, impedance, and class topology.

Power Matching

Match the amplifier's RMS output to the subwoofer's RMS rating, at the impedance you are actually wiring. Underpowering is what kills subwoofers, because an amp driven into clipping sends the voice coil a distorted signal it cannot dissipate. Overpowering with the gain set correctly is fine; the sub draws what it needs. Aim for amplifier RMS at 100% to 150% of the sub's RMS rating.

From this catalog: the Prodigy NBM1200.1 at 1200W suits a single 1000W RMS sub. The US Acoustics Tony at 6000W suits dual 2500W RMS subs or one 4000W competition driver. The US Acoustics Phil at 8000W is for the largest competition installs. Browse the drivers these are matched to in car subwoofers, or by size in 10 inch and 12 inch.

Impedance Matching

Subwoofers come single or dual voice coil, typically 4, 2, or 1 ohm per coil. How you wire them sets the load the amp sees, and every monoblock publishes its rated output at specific impedances. Wire to the load where your amp makes its rated clean power, not to the lowest load it survives.

Class Topology

This catalog spans three classes.

Class D. The efficient topology: less heat, less current drawn from the vehicle's electrical system. Image Dynamics SQ series, Triton NS12001, Wavtech Link series, Prodigy NB series, Arc Audio X2, Crescendo Revolution 3A1, and the US Acoustics lineup. The right answer for most daily-driver subwoofer builds. Full range in Class D amplifiers.

Class AB. Bias current eliminates crossover distortion at the cost of efficiency and heat. Tru Technology Tungsten Grande, Audio Wave Excel, Audio Wave Aspire Pro USA Monoblock, Crescendo Revolution 5A1. Reach for it when bass quality matters more than maximum SPL. Full range in Class AB amplifiers.

Class A. The reference tier. The output devices conduct continuously, which is why it makes the cleanest bass available in car audio and why it runs hot and draws hard. The Audio Wave CR-30X at $18,500 is the example here. Full range in Class A amplifiers.

Brands in This Collection

US Acoustics. The high-output Class D line, and the deepest bench here: Mike at 1500W ($329.99), Big Ben at 3500W ($599.99), Tony at 6000W ($999.99), and Phil at 8000W ($1,249.99). Built for high-current SPL duty in daily drivers and dedicated competition cars. See the full US Acoustics lineup.

Image Dynamics. SQ600.1D at 600W ($399.99) and SQ1200.1D at 1200W ($504.99). Class D tuned around the brand's own IDMAX and IDQ drivers, which is the pairing we reach for most on an SQ sub stage. See Image Dynamics amplifiers.

Wavtech. Link5001Mini ($299.99), link1000.1mini ($399.99), and Link1500.1plus ($699.99). Compact-chassis Class D for builds where mounting space is the binding constraint. See Wavtech.

Prodigy Audio. NBM1200.1 at 1200W ($272.99) and NB2800.1 at 2800W ($527.99). The value entry, with the strongest power-per-dollar in the collection. See Prodigy amplifiers.

Arc Audio. X2 650.1 at 650W ($568.00) and X2 1100.1 at 1100W ($758.00). Class D from the X2 series, built for SQ builds that want a known quantity on the sub channel. See Arc Audio.

Crescendo. Two Revolution monoblocks, and they are not the same animal. The 3A1 ($569.99) is Class D, 1000W RMS at 1 ohm on the IRS2092S chipset, and it is the competition-oriented one. The 5A1 ($749.99) is Class AB and full range, holding 450W at 4, 2, or 1 ohm without the output moving. That flat-across-impedance behavior is unusual and it is why the 5A1 works as a midbass channel as readily as a sub channel. See Crescendo amplifiers.

Tru Technology. Tungsten Grande Class AB monoblock ($1,999.99). Audiophile circuit topology with no shortcuts taken on the output stage. See Tru Technology.

Audio Wave. The reference end, and the widest price spread on this page: Active 250 full-range monoblock ($2,499.99), Excel Class AB monoblock ($3,099.99), Aspire Pro USA Monoblock Class AB ($8,999.99), and the CR-30X Class A monoblock ($18,500). See Audio Wave amplifiers.

Triton Audio. NS12001, 1200W Class D ($399.99). One model, specced for the straightforward daily-driver sub build.

Once the amp is picked, the enclosure decides what you actually hear. We cut ours in Tullahoma on ShopSabre routers from 3/4" Langboard Elite MDF: see subwoofer enclosures. If you are tuning an active system, the DSP lineup is the other half of the signal chain.