Sonic Electronix Certified Amplifiers* are thoroughly tested by our in-house experts for accurate power output compared to manufacturer stated ratings, ensuring you know the true power ratings before you purchase your amplifier.
Our certified amps are professionally tested to determine true amplifier power output using our SMD Amplifier Dyno. We put these amplifiers through both a certified test and a dynamic test to give you the most accurate information about these amplifiers. When in certified mode, the SMD Amp Dyno utilizes the SMD patented DD-1 distortion detection system to determine whether it is measuring clean power or not. This is accomplished by slowly building power input until the system measures greater than 1% harmonic distortion and takes a final power reading and battery voltage rating at that point. The Dynamic Test utilizes industry standard burst signals to capture the power generated by the amp.
The benefits of these tests are to ensure you don’t have to guess as to whether the amplifier you’re purchasing will meet your power needs. Some amplifiers have greatly exaggerated power ratings which are attempting to deceive consumers with huge numbers rather than accurate ratings. With the Sonic Electronix Certified Amplifier rating, you know exactly what you’ll be getting!
Buying an amplifier for a car audio system can be a daunting task. It can be a challenge for someone new to the industry to select the perfect amplifier for their application, so we’ve put together this guide to help you find out what type of amplifier you need for your new system. Remember – you should either choose an amplifier first and build your system around it, or you choose the other components first and choose an amplifier (or amplifiers) to power the components. This guide assumes you have an idea of what type of system you want without any idea about the amplifier.
Let’s get started!
Selecting a Channel Configuration
All amplifiers are designed to output power into different “channels”. This helps pair the amplifier to the application it’s being used in. The most common amplifiers are 2-channel, 4-channel, and monoblock. Now, just because an amplifier is branded as “2-channel” doesn’t mean it’s only capable of powering 2 speakers. In theory, it’s possible to have as many speakers as you want paired with a 2-channel amp, it will just change the impedance (ohms) and change how the power is distributed between the speakers. Even though it’s possible to wire many additional speakers, it’s most common to use a 4-channel amplifier for 4 speakers, a 2-channel for 2 speakers, and so on.
Here’s a list that helps identify each different amplifier channel configuration and more information about each one.
Can be used to power one set of speakers (2 total speakers)
Most commonly used to power a subwoofer, or multiple subwoofers
Usually has Class A/B Circuitry, but can also have full-range Class D as well
Perhaps one of the most popular selections, 2-channel amplifiers are great for multiple purposes. Two channel amplifiers output dedicated power to two separate channels, great for powering one set of car speakers (2 total speakers). The two channels can also be combined, or bridged together to provide more output to one dedicated channel, and is commonly done to power a subwoofer or subwoofers. 2-Channel amplifiers are stereo, meaning they have a Left and Right output. This is important for staging, and tuning. These amplifiers are capable of playing what is considered the full spectrum of sound that humans can hear, usually around 20-20,000 Hz.
Bridgeable (most of the time)
Usually used to power two sets of speakers (4 total speakers)
Also able to be used in other configurations, however this is not as common
Usually has Class A/B Circuitry, but can also have full-range Class D as well
Another popular option, 4-channels, are commonly used to power an entire set of door speakers (4 total speakers). 4-Channel amplifiers are also bridgeable, allowing for a ton of configurations, but the most popular application we find these amplifiers in is powering door speakers.
Mono (one channel, no Left/Right differentiation)
High-powered car amplifier
Not full-range since subwoofers do not play higher frequencies
Usually used to power one or more subwoofer
Commonly has Class D circuitry, however can also have Class A/B as well
Monoblock amplifiers are designed primarily for subwoofers. Subwoofers require a lot more power than standard speakers, and the signal does not need to be as clean as the signal going to a full-range amplifier. Bass doesn’t need to be processed as much for high quality sound, like a really nice full-range amplifier does. Monoblocks are also not usually full-range capable, because higher frequencies are not played by subwoofers. Having these amplifiers capable of playing high frequencies would be a huge waste in efficiency. Because subwoofers require much more power than smaller tweeters or door speakers, monoblock amps are designed for maximum efficiency and power output first.
Front 4-channels are stereo/1 channel is mono
Basically a 4-channel amp and a monoblock amp combined
Allows an entire system to be powered from one amplifier (4 speakers, 1 or more subwoofer)
Good for those who don’t want multiple amplifiers powering their entire system
5-Channel amplifiers are basically a mixture of a 4-channel amplifier and a monoblock amplifier, built into the same chassis. This helps eliminate the need for multiple amplifiers and elaborate wiring scenarios. These amplifiers are a great, simple solution for those looking to power 4 speakers and a subwoofer. They’re a bit more difficult to use for high powered audio applications, since 5-channels are usually only capable of running around 600-1000W RMS. This amount of power is perfect for mid-tier audio systems though.
Front 2-channels are stereo/1 channel is mono
Basically a 2-channel amp and a monoblock amp combined
Most commonly allows an entire truck system to be powered from one amplifier (2 speakers, 1 or more subwofer)
3-Channel amplifiers are a smaller version of a 5-channel. They’re basically a 2-channel amplifier and a monoblock combined. They’re most commonly used to power an entire audio system in 2-door truck, or other small vehicles similar to this. You’ll also find 3-channel amps used to power just the front speakers and a subwoofer in a budget system.
Similar to a 4-channel amplifier, but with 2-extra channels
Allows powering of a center channel, or two additional sets of speakers
Usually for specific audiophile applications
6-Channel amplifiers are usually reserved for audio enthusiasts or those with specific audio applications in mind. These amplifiers are most commonly used in vans, SUVs, and boats where you may require more than the traditional 4-speaker setup. They can be used in a lot of installations, but usually they’re bought with a certain application in mind.
Determining Power Requirements
Trying to match up your system’s power requirements with an amplifier can look confusing, but really it’s easier than it seems. The first thing to always remember is to only look at RMS power. Looking at peak or max power without a deeper understanding of it, will only confuse you. Secondly, impedance (or ohms) is a way to measure resistance. All speakers have an ohm rating, or impedance that tells the amplifier how much power to output. Lower impedance means more wattage from the amplifier. At 4 ohms an amplifier will output less power than at 2 ohms; however, an amplifier is more comfortable running at higher impedance and will tend to run cooler. For example, an amplifier at 4 ohms may put out 75 watts RMS, and at 2 ohms this same amplifier will output 100 watts RMS. Finally, you’re going to want to match up the impedance and RMS wattage of the speaker and amplifier. For example, if the manufacturer specifies that each speaker will require 100 watts RMS at 4 ohms, you will want to find an amp which pushes between 70-130 watts RMS at 4 ohms.
For more information regarding impedance, check out this video on matching subwoofers and amplifiers:
Although you will get sound from a speaker even if you’re powering it with less than 70% of the rated RMS power, it’s usually not advised. When underpowering a speaker or subwoofer there’s a problem you’ll run into called “clipping”. This occurs when the amplifier tries to push more power to the subwoofer or speaker than the amplifier is safely capable of reproducing. For more on clipping, check out this video.
Determine if Auxiliary Battery is Required
Batteries are underused in car audio, when in reality they should be overestimated and overused. It’s understandable, considering that adding an additional battery is a bit of an investment to an already expensive complete system build, however the investment can be put to exceptional use in moderate and higher powered systems. Personally, I agree with the rule of thumb that systems running over 1000 watts of total RMS power should ALWAYS have at least an upgraded starting battery. An auxiliary battery should also be highly considered in these types of systems. The reason for this is, car audio systems are very demanding when it comes to using power. Your vehicle has a battery used to start your car, but also power things like your head unit, air conditioner, power windows, illumination on the dash, and, perhaps most importantly, headlights.
A common symptom you’ll see when adding a higher powered car audio system (600W RMS and up) is that when the bass hits, you’ll see your headlights dimming. This is because bass is very demanding, and every time it’s hitting it’s pulling a ton of voltage from your battery. In order to combat this, I’d personally recommend any system over 600 watts of RMS power (or fuses that add up to 60 amps or more) should highly consider either upgrading their starting battery to one more capable of keeping up with their system, or adding an auxiliary battery.
Determining Wire Gauge
Now, you’ve picked out your amplifier, you’ve picked out the speakers and subwoofer(s). You’re reading to get this system ordered and installed. Hold up. One last final thing to mention is wiring. Now, we’ve stressed before the differences between Copper Clad Aluminum(CCA) and Oxygen-Free Copper (OFC) wiring before in some of our videos and blogs. This is important to consider, but mainly we’re going to assume you went with OFC and are curious about the gauge of wire to choose.
The fuses on your amplifier (if your amplifier has them, lately more manufacturers have been opting out of external MIDI fuses and relying on your main fuse near the battery to protect your amplifier) are a good place to start to determine what wire gauge to choose. The reason for looking at fuses instead of rated power, is because power ratings with amplifiers can be very misleading. Reliable manufacturers in the industry who follow CEA compliant power ratings are much easier to determine wire gauge for than manufacturers who just list peak power or over-inflate their RMS power ratings.
Looking at total RMS power for your amplifier(s) is the way to determine the main run from your battery to your amplifier area. Another factor to consider is the length of the wire run. If you have your amplifiers under your front seat, you may be able to get away with a small gauge then if you’re running it to a trunk. Consider the RMS power, the length of the run, and the quality of wire that you’re choosing to find out if you’re using large enough wire to allow for proper system requirements.
Now that we’ve talked about some of the main points to consider when purchasing your next car audio system, get to building out that system! If this seems like a bit too much info for you, and you just want that sound in your car, give us a call! We have experts on the line who are complete car audio enthusiasts who will be happy to help you get exactly what you’re looking for!
The gain adjustment control on an amplifier is one of the most misunderstood concepts in the car audio world. Well, basic concepts that is. The purpose of the gain control is to level match the head unit’s output voltage to the gain structure of the amplifier so that the input is not overdriven which would introduce clipping.
We first covered how to set your gains by ear in the article titled “How to Tune and Adjust Amplifier Gains and Bass Boost”, however this is not a great method to use because all of our ears are different and we often can’t hear the most deadly distortion. For those of us with a Digital Multi-Meter (DMM), setting your gains this way is the most effective method aside from using an oscilloscope.
Let’s get started.
Step 1: Disconnect the positive speaker wire(s) from the positive terminal(s) on the amplifier.
Step 2: Turn off all EQ settings or set them to zero, such as Bass, Treble, Loudness, Bass Boost, Processing and EQ functions.
Step 3: Turn the input sensitivity (gain) to zero. For most amplifiers, this is counter clockwise (CCW) to the farthest point. Make sure the input voltage selector is on “Low” if the amplifier has one.
Step 4: Set the head unit volume to 3/4th of its maximum volume. Turn your radio dial to it’s maximum volume and multiply that number by 0.75, this will get you 75% of your maximum volume.
Step 5: Now we must find the voltage that we need to set the gain to. Voltage = square root of watts x ohms. For example, a 500W RMS amplifier at 2 Ohms would configure like this: 500W RMS X 2 Ohms = 1000W. Now take the square root of 1000W and your voltage should be 31.62V if you’re running an amplifier with one gain control. Some amplifiers have 2 gain controls so treat it as two separate amplifiers. If the amplifier is 100W RMS by 4-channels for a total of 400 watts but has two gain controls, use the power output of ONE channel and use that for your voltage calculations. (EX: Square Root of 100W RMS x 2 Ohms = Voltage for each gain control per channel.)
Step 6: Make 100% sure the positive speaker wire(s) are disconnected from the amplifier. Once double checked, insert a test CD with a sine-wave test tone at 0dB level in the frequency range of 50Hz to 60Hz for a subwoofer amplifier or 1,000Hz for a midrange amplifier. Set the head unit to repeat for continuous play of the test tone.
Step 7: Connect a digital multi meter set to AC Volts to the speaker outputs of the amplifier. The positive voltmeter lead will touch the positive speaker wire terminal and the negative lead will touch the negative speaker terminal. If everything is done correctly, a low voltage will be displayed on the voltmeter, usually 6V or below. If you get a high voltage right away, repeat steps 2 and 3. Slowly turn the input sensitivity (gain) up on the amplifier until the target voltage you calculated earlier is reached.
Step 8: Adjust every amplifier in your system using this method; each amplifier is now set to its maximum unclipped output level. Turn the volume on your head unit to zero and turn it off.
Step 9: Reconnect all the positive speaker wire(s) to their respective positive terminals. Double check all wiring and proceed to turn the headunit on. Remove the test tone CD and play a musical track that you are familiar with. Listen for any distortion in the form of buzzing, crackling, hissing, whomping, and various other noises that intrude on the instruments of your music.
This is an accurate way to set your gains to prevent distortion and clipping in your system but it is not the absolute best method. If you really need it done right, use an oscilloscope which can show you if your setup is clipping and distorting or not.
When you look at an amplifier’s specifications you may come across one that says “Damping Factor”. The damping factor describes the ability of the amplifier to control the movement of a speaker, more specifically, unwanted movement. This is especially important for lower frequency speakers such as car subwoofers. Damping factor can be looked at from many different angles and several factors affect the overall damping factor in a system.
In a simple sense, the damping factor tells you how well an amplifier can control a speaker system. The larger the number associated with damping factor the better an amplifier is at controlling speakers. Anything above 100 tends to be very good while below 30 is poor. Most aftermarket car audio amplifiers to date won’t have such poor damping factor specifications to the point where it would become a concern for the average listener if they follow specs. This means that if you’re trying to get the best sound possible you need to look for a higher damping factor, assuming everything else is equal. Below I will get slightly more technical, so the above information is very simplified.
Most manufactures do not specify damping factor accurately in their specification charts. An accurate damping factor will look something like this: Damping Factor = 100 at 4 Ohms. Rarely is the impedance (ohms) listed. Damping factor is the speaker systems final impedance (load impedance) divided by the amplifiers output impedance. So if you have one speaker at a perfect 4 ohms impedance and divide it by the amplifiers output impedance, let’s say 0.4, you get a damping factor of 100 (4.0 / 0.04 = 100). If your final impedance is 1.0 ohms and the amplifiers output impedance is 0.04 your damping factor becomes 25 (1.0 / 0.04 = 25). Using this formula, as long as you know the amplifiers output impedance and your speaker systems final impedance, you can calculate the damping factor. This is why it is important for the manufacture to list what impedance they list their damping factor at for the most accurate number. However, using the formula you can find out if you have most of the other information.
Let’s throw a monkey wrench into the mix. In the real world, a speaker’s impedance is affected by everything in the system. A car audio speaker will fluctuate anywhere from 1 ohm to even 30 or 40 ohms while it is operating. So if damping factor is based off of the speaker’s impedance but it’s always jumping up and down then that means the damping factor can’t be a single number. Damping factor is a major simplification of what is actually going on but it is still important! If everything is relatively equal you would be able to notice the difference between a damping factor of 100 and 25. While this should not be your go-to to find the best quality in an amplifier, if all the other specs are closely matched you can look at it to help make a final decision. Knowing all the specifications and what they mean can really help put everything into perspective when selecting an amplifier and speaker combination. Remember, it all comes down to what sounds best to YOUR ears.
Ohms are the measure of resistance to the flow of electricity in an electric circuit. Think of it like a freeway, the more cars congesting the freeway, the slower everyone will move due to traffic. Electricity, like the cars, can be slowed down in the circuit due to higher resistance. The higher the ohm value, the more difficult it is for current to flow through a circuit. Likewise, the lower the value, the easier it is for current to flow. Based on this, is there any other differences between the most common 2 and 4 ohm impedances?
Certain amplifiers are designed to power subwoofers at different impedances (ohms). For example, a 2 ohm rated amplifier will power a 2 ohm subwoofer, so long as the woofers “final impedance (ohms)” is 2. You can connect multiple subwoofers together and run them off an amplifier, so long as their final impedance is equal to the amplifiers impedance. We cover this in a different article. If you have 100 watts at 2 ohms, and 100 watts at 4 ohms, is there a difference? The answer is subjective, you will hear people say there is a sound difference, and some say there isn’t. It depends on how efficient the amplifier runs at the specified ohm level, as well as the speaker itself.
If you get technical, the different resistance values of a speaker will change the sound slightly, assuming wattage is the same. A lower impedance subwoofer has a voice coil with fewer windings, meaning less weight. A higher impedance subwoofer will have more coil windings, meaning more weight. It has more windings to counter act the resistance, so it’s like adding more lanes to the freeway to ease up traffic. This slight difference in weight will produce a slight sound quality difference. At 2 ohms you tend to have more projection of sound (louder), which causes poorer sound quality. At 4 ohms you will have less mid bass frequencies then at 2 ohms; however the sound quality is slightly improved.
If you’re not an audiophile, does this matter? Honestly, no it does not. Do not let this be a make or break when looking for sound system components. Two of the same subwoofers, just with different impedances, will produce almost the same sound if they are run at the same wattage. The difference in sound is so slight that it has little impact, especially when dealing with subwoofers, that you likely can’t tell the difference.
You’re shopping for subwoofers and you see two identical looking woofers. You read the specifications on the label and notice they are the same for both car subwoofers. The price is slightly different and the model numbers are slightly different, but everything else is the same! But wait, you turn them over and one says “Single 4 Ohm” and the other says “Dual 4 Ohm”. This is no deception, your eyes don’t lie. Before you bag one up and take it home, do you know the difference between a Single and Dual voice coil subwoofer?
First of all, what is a voice coil? The voice coil in a subwoofer is a coil of wire wrapped around a cylinder called the former, which accepts the amplifiers current. Current from the amplifier causes the coil to react with the stationary magnet, moving the former up or down. The former is attached to the speaker cone which produces changes in air pressure when moved, producing sound.
A single voice coil (SCV) is one length of wire wrapped around the former. A dual voice coil (DVC) has 2 coils of wire wrapped around the former. A single voice coil subwoofer will have a positive and negative terminal, while a dual voice coil subwoofer will have 2 positive and 2 negative terminals, one for each coil. The price of a DVC subwoofer will usually be slightly higher than its SVC brethren due to the extra coil. There is no performance advantage between the two types of voice coils, so why bother?
The advantage of a DVC subwoofer over the SVC subwoofer is your available wiring options and flexibility. Single voice coil subwoofers can only be wired at the ohm level specified, for example 4 ohm. A dual voice coil will say 4 ohm, but it will actually wire to 2 ohm or 8 ohm. That last sentence alone tends to blow the minds of many, you are not alone. The ohm level needs to match up with the ohm level your amplifier can handle. A DVC woofer has 2 wiring options while the SVC has only one option.
When everything is all said and done, the only real difference between a single and dual voice coil subwoofer is the number of coils, which means a greater wiring flexibility. The power handling, frequency response, box volume specifications, etc. will remain the same for both types of woofers (except in rare cases). Feel free to use the Sonic Electronix subwoofer wiring diagram to help you configure the right subwoofers.
Two of the most important specifications to look at when matching subs to an amplifier are impedance and RMS rating. The total combined RMS rating of all the subwoofers should not exceed the power the amplifier produces at the impedance that your subwoofer draw. Remember, ohms measure resistance. The lower the ohm rating, the lower the resistance. The lower the resistance, the higher the power flow from the amplifier.
Here is an example that will help illustrate how to figure out possible wiring combinations. For our example, we will use a Kicker ZX750.1 monoblock amplifier. Despite the monoblock designation, a monoblock amplifier can power more than one subwoofer. In fact, monoblock amps usually produce greater amounts of power than multi-channel amps, which makes them ideal for powering car subwoofers.
The Kicker ZX750.1 has the following power specifications:
– RMS Power (4 ohms) 375 watts x 1 channel
– RMS Power (2 ohms) 750 watts x 1 channel
Based on the amplifier’s specifications, the possible subwoofer combinations are as follows: - 2 subs: 4 ohm SVC - 1 sub: 2 ohm SVC - 1 sub: 4 ohm DVC - 2 subs: 2 ohm DVC
Since we know that this amp can provide power up to 750 watts of RMS at 2 ohms, we should use a subwoofer combination that requires less than 750 watts. Add the RMS ratings of each subwoofer together and make sure it is less than 750 watts. Most manufacturers recommend slightly overpowering your subwoofers. Contrary to popular belief, underpowering your subwoofers can lead to blown or damaged cones. Of course, this refers to RMS ratings, so be sure that you do not exceed peak power ratings.
I have included a table below to help you learn how to match subwoofers with amplifiers. This is not a comprehensive guide to wiring but it does contain some good guidelines.