If you’re shopping for a subwoofer amplifier for your car stereo system, you may have noticed that some have two sets of speaker terminals. In most cases, it’s reasonable to assume that an amp with two positive and two negative speaker connections would be a stereo amp. As you’ll soon see, this isn’t always the case.
Sub Amp Design Process
When an engineer is designing a car audio amplifier, there are lots of criteria to keep in mind. First and foremost is the amount of power the amp will need to produce. Power production has the most significant impact on the cost of an amp, since it determines the size of the heat sink and the power supply, and the number of power supply and output switching devices.
Next, the features to be included in the amp have to be taken into account. All subwoofer amps have a sensitivity control and most have an adjustable low-pass crossover. Some will add an infrasonic filter, a remote level control knob and perhaps a bass boost circuit. The cost of the parts (switches, potentiometers, op-amps, capacitors and resistors) adds to the cost of the amplifier, but also its flexibility and value.
Use What You Have in Stock
It should come as no surprise that a mono sub amp needs only a single positive and negative speaker terminal. If the company designing the sub amp already has a four-position terminal block in its inventory, then they can use that to eliminate the cost of adding another component they need to stock.
Inside the amp, the two positive terminals are connected together, as are the two negative terminals. The extra connections are added for convenience to make wiring multiple subwoofers easier. If you have a vehicle like a Jeep Wrangler that is commonly upgraded with two separate subwoofer enclosures, being able to connect two sets of wires is easier. Is there a performance benefit? Not really. If you need to run two sets of speaker wires, the extra connections make that easier, but that’s about it.
Upgrade Your Car Stereo with a Subwoofer
If you want to dramatically improve the performance of your car stereo system, drop by your local specialty mobile enhancement retailer today and ask about adding a subwoofer system. They’ll be happy to demonstrate different sub, amp and enclosure options for your vehicle.