Tag: car amplifier

How To Strap Two Amps Together, Double Your Power!

strap

For this how-to, I’m going to use the DC Audio 7.5k .

For the most part, “Strapping” – aka ‘Bridging’ – TWO amps together is done to get Double the @1ohm Power Rating of One Amp. This makes the setup – AFTER “strapping” – stable ONLY to a 2-ohm final load . That, in of itself, is fairly confusing so here’s an explanation…

First, it is of the UTMOST IMPORTANCE that you ONLY ‘strap’ two IDENTICAL TWIN AMPLIFIERS! Moreover, it is also important to make sure that the amplifiers have the ability to be strapped (i.e. the features necessary to successfully perform this), and that ‘Strapping’ is a manufacture confirmed ability of the amplifiers.

DC Audio 7.5k

DC Audio 7.5k

  • 4-ohms: 2000 watts x 1 ch.
  • 2 -ohms: 4400 watts x 1 ch.
  • 1-ohm: 7500 watts x 1 ch.

From the above specs, we establish that ONE DC Audio 7.5k is able to put out 7,500w RMS @1-ohms. Therefore, in theory, If we strap TWO DC Audio 7.5k together we can achieve 15,000w RMS @2ohms!!

The most crucial part of successfully Strapping two amps together is the Wiring! Starting with the Easy part, RCAs:

RCA SIGNAL CONNECTIONS:

    • Step 1. Connect the Master amplifier to the head-unit (duh!) and set the amplifier’s output-master/input-slave switch to Output Master.
    • Step 2. Set Slave amplifier output-master/input-slave switch to Slave Input.
    • Step 3. From the ONE RCA-Connector – that has a line from said switch – Connect an RCA cable from the Master to Slave amplifier.

DO NOT USE THE PAIR OF RCAS LABELED ‘OUTPUT’!!!! This “Output” will ONLY send an AUDIO SIGNAL, and Will Not allow for the following important part to happen……

Intermission: The Output-Master/Input-Slave Switch , if you haven’t already figured it out, will turn one amp into the Masterand the other into the Slave. But what does this mean exactly? This means – The Master amp will be in absolute control of the Crossover Points, The Gain, & The Remote Level Control. Implied, the SLAVE will have absolutely NO control abilities, those settings will be turned Off . Therefore to “Tune” the amps – plural – you ONLY ‘Tune’ the Master amp!

Next part of the install is where everyone gets lost; the speaker wire connections.

Untitled

 

SPEAKER WIRE CONNECTIONS:

  • Step 1. Connect 12-Gauge Speaker Wire from the Positive (+) Speaker Output on the Master amp to the Positive Terminal on the Subwoofer (+). Amp (+) to Sub (+)
  • Step 2. Connect 12-Gauge Speaker Wire from the Positive (+) Speaker Output on the Slave amp to the Negative Terminal on the Subwoofer (-). Amp (+) to Sub (-)
  • Step 2.5. Please Re-Read Step 2 . This is the part EVERYONE gets wrong. 
  • Step 3. Connect 12-Gauge Speaker Wire from the Negative (-) Speaker Output on the Master amp to the Negative (-) Speaker Output on the Slave Amplifier. Amp (-) to Amp (-)

These connections is what Physically ‘bridges’ the amps together!

From this point on you can go about the install as you would any other install. Make sure all your connections are made properly, tighten everything down, mount what needs to be mounted, etc… Then, start the Tuning process; tune the MASTER AMP ONLY!!!

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How to Tune an Amplifier

tuning_an_amp

In order to get the absolute best performance & sound quality from your amplifier it is very important to know exactly how to properly tune an amplifier. The most common misconception of tuning an amplifier is that the settings are intended to ‘give you the most power output’, this is not the case. This article will break down exactly what each common setting on an amplifier does and how to properly tune those settings.

For this example we are going to use the DC Audio 7.5k as an example. Onboard, it has the most common settings found throughout the market. The names might be a bit different, but they do the exact same thing, more on that later. Moreover, this article will cover each setting Right to Left – use the picture below to follow along – ending at the Gain, which is easily the most important setting of them all.
DC Audio 7.5k

  • Master/Slave Switch

  • The Master/Slave Switch is ONLY ever used when “Strapping” the amp with another identical-twin amp (i.e. Same Series, Model, etc..). Stay tuned for a future article on how this is done, But for this explanation we are assuming ONE amplifier one, so this switch must stay on MASTER. What does “Slave” do? Stay tuned for the explanation on “Strapping”.

  • Phase

  • Inverted Subwoofer
    The job of the phase setting is to do one thing: change the polarity/direction of the sub(s) being ran off the amp. The most common reason why you would want to use this setting is when you have an ‘inverted’ subwoofer*. You could, however, just as easily swap the polarities of each terminal and accomplish the same thing. Another reason why you would use the setting is if you have two drivers & two amps (one per driver), and one is “Out of Phase”. This means ONE driver is playing OUTWARD (away from the enclosure) and the ‘Out of Phase’ driver is playing INWARD (into the enclosure). What happens in this case is , in theory, the two sound waves coming off the driver cancel/eliminate each other, giving a very undesirable result. So when you hear someone say the driver is “out of phase” THIS is the go-to setting to try to fix that. Beyond that, rarely can an audible change be actually heard, but there are more variables beyond just the setting that will make a change.

    For our example, we assume the driver is wired properly, so this is left at 0

    *Inverted Subwoofers are often done for one of two reasons:

    1. To utilize the absolute most volume of the enclosure. Without a subwoofer displacing the air within the enclosure you have FULL use of that space.
    2. Because it looks cool. Yes, really.
  • LPF

  • Low Pass Filter.The LPF can be thought of as a “Ceiling”. The LPF will not allow the frequencies above where you set it to pass through. Technically speaking, there is a “Roll Off”, the LPF isn’t just a ‘wall’, but we won’t get into that here. The setting is intended to ‘filter out’ frequencies that which the driver – in this case a subwoofer – cannot play and/or will harm the driver if it does so. There isn’t a “right way” to set this, there is only the way the setup is configured and also what the limitations of the driver are.

    Suggestion: The most common (read: ‘dummy proof’) setting is 80Hz-120Hz

    Consider this, however, if the Full Range stage of your setup (i.e. Door Speakers) for some reason are incapable of playing below 120Hz , then you want the subwoofer to pick up at 120Hz; so the LPF will be set at 120Hz! This is because you wouldn’t want your sub Playing 80Hz and Down, then your Full Range Playing 120Hz and Up, because then you will have an inaudible gap between 80Hz-120Hz (i.e. Dead Space). For all intents and purposes we suggest to stick 80Hz; this will make sure all ‘mid-range’ is filtered out, and its often the most easily recognizable crossover point. Unfortunately, Most Amps do not tell you where a specific crossover point is , so you definitely need to ‘Eye Ball’ it. An overlap of frequencies – Sub vs Full Range – isn’t a “bad thing”, but for those who want the “Perfect Setup” you will have to have the right tools to hit the points you want. The only way of doing this is with the use of a Crossover Calibrator; we use the SMD CC-1 in our installation department to hit these points accurately.

  • Bass Boost

  • The Bass Boost is fairly self explanatory. It literally boosts the frequencies that you send it. We DO NOT recommend using this setting, if at all possible, because drivers go here to die. Assuming the amp is tuned right, there is seldom a reason to come to this setting. The reason it exists is because:

      1. Manufacture’s need to compete with another, so if multiple amps have this setting, then theirs does too
      2. It can actually have a practical use

    The latter only ever happens when the Full Range completely over powers – or “Drowns Out” – the subwoofers’ outputs. In order to “balance” the setup, you go to the Bass Boost to give the output a bit more output. THIS ISN’T A VOLUME KNOB!! You are toying with introducing a distorted signal if this setting isn’t used responsibly. Use at your own risk.

    Suggestion: Leave at 0

  • Subsonic

  • For all intents and purposes think of the Subsonic as a HPF (High Pass Filter), the ‘opposite’ of the LPF, or as a “Floor”. The Subsonic will not allow the frequencies below where you set it to pass through. Like the LPF, this setting is intended to ‘filter out’ frequencies that which the driver – in this case a subwoofer – cannot play and/or will harm the driver if it does so. This setting is often established by the limitations of the driver. For example, the NVX VCW104 has a frequency response of 20Hz-220 Hz, which means it is physically incapable of playing below 20Hz. This tells us that if we want to protect the driver, we should set the subsonic to 20Hz. Many in the industry will say that the ideal setting, for this example, would be ~25Hz because “just because its capable of doing 20Hz doesn’t mean it Should”. The often cited analogy is “your car Redlines at ~7,000 RPMs, that doesn’t necessarily mean you SHOULD ride the engine at 7k just because it can”. Nevertheless, in a properly tuned setup, and with an able/responsible user, there is very little concern for setting this point to the limitation presented by the driver.

    Suggestion: Set to 20Hz , for most subwoofers

  • Gain


  • This is NOT a volume control!! Whatever you want to call this setting, it is intended to do One thing and that is to match the sensitivity of the source/headunit. So, in theory, if your headunit provides a solid 5v out of the preouts, then the Gain (Sensitivity, Level, Input Level, Sensitivity Input, (V)) will match that when set properly. Due to several variables it is more likely that it is not going to match EXACTLY (i.e. at 5v) but it will come fairly close. Unfortunately, without special tools or an oscilloscope it is very hard to get this “Right”. It isn’t impossible to set this without special tools however. In fact, most installer set up their customers’ amps by ear! This will be the most common method you – the reader – will use. In addition, there is also a creative way of using a common DMM (Digital Multimeter) & Ohm’s Law to establish an AC Voltage Figure to aim for when adjusting the Gain; a quick search for this method will generate a lot of useful information. However, it is important to know that using the DMM method ASSUMES that the figures/variables you use are SPOT ON , which – to be fair – is not likely. This is because the rated figures on an amp are often rounded up/down, and – worse – a lot of manufactures will give overrated figures. So, using this method can be precarious if you the figures aren’t True To Spec.

    Suggestion: Too many variables to provide a “right answer”


    To Recap:
    Master/Slave – Master (Assuming ONE Amp)
    Phase – 0
    LPF – 80Hz
    Bass Boost – 0
    Subsonic – 20Hz
    Gain – ____
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    Car Audio 101: Car Amplifiers

    An amplifier is really a simple piece of your aftermarket sound system. A car amplifier basically amplifies a signal from a source (in the case of a car sound system, your stereo) to a much greater signal. Signals from source units are typically fairly low voltage, which is fine for most speakers (but not subwoofers), amplifying your speakers will make them perform to their full potential. Now, your speakers can be powered by just your source unit, but a subwoofer will require an amplifier. Giving your system more power will improve both sound quality and how loud your system will play.

    When looking for an amplifier, it’s important to know what you intend to use it for. If you’re simply adding a subwoofer to your system you will only need a monoblock amp while with a complete system (4 speakers and a subwoofer) your best bet is either a 4 channel and a monoblock or a 5 channel amplifier. It is critical to the success of your sound system that you match up all of your equipment (speakers, subwoofer, source unit) with the right amplifier to make sure everything is powered properly to give you the best sound possible.

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    Sonic Electronix Certified Amplifiers

    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!

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    How to Adjust Amplifier Gains Using a Digital Multi-Meter

    71-00

    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.

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    Damping Factor

    The Damping Factor of Your Amplifier Tells You How Well it Controls The Movement of Your Speakers

    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.

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    RMS V.S. Peak Power

    PeakvsRMS

    Car audio is all about the power ratings. The objective is to match up the power of your amplifier with the power handling capabilities of your speakers or subwoofers. Seems simple enough…until they throw around words like RMS, peak, max and dynamic and then throw the word “power” after it. As a basic rule of thumb, RMS power is considered true power and all other ratings are relatively mute when making comparisons or finding that perfect system. Below I go a bit more in depth with the different types of power.

    RMS Power Ratings:
    The RMS power rating is the measure of continuous power that an amplifier can output, or a speaker can handle. RMS power is derived from Root Mean Square which is a statistical measurement of the magnitude of a varying quantity and is applied to voltage or current. Yeah…you can disregard that and just concentrate on the fact that RMS power should be what you use to compare any car audio products. Even the RMS power has its flaws and inaccuracies, but for the most part it’s the most accurate depiction of real, continuous power so far. Here is the kicker, the way a company calculates its RMS power is different for each company which then makes RMS power inaccurate as well. Not so fast, all products that are CEA-Certified are tested using the same testing methods and can be compared in an apples to apples fashion. For more information on CEA Certification, read our articles on CEA-2006 and CEA-2031 compliant devices.

    Peak, Max or Dynamic Power Ratings:
    No matter how you word it, this form of power rating refers to the maximum amount of power an electronic device can handle or output in an instant without damage. Often times this rating could be reached with a big bass hit or a very loud note in a song as it’s played using the correct amplifier. We do not recommend that you use the peak, max or dynamic power rating when configuring your system because it does not reflect the products capability under everyday use. So why then is this power rating still listed if it’s somewhat exaggerated and unreasonable? Manufactures still advertise peak power because most consumers are unaware of its meaning and believe that larger numbers are better. Peak power is used to make a product seem more powerful than it actually is, sometimes even five or six times more powerful than the RMS rating.

    And there you have it. Play it safe and stick with RMS power ratings while staying away from peak, max or dynamic power listings. Try to find CEA Certified products to get the best apples to apples comparison!

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    How to Test a Car Amplifier

    test_amplifier

    How do you test the power output of your car amplifier? It’s simple with the help of a digital voltmeter. Just make sure your amplifier is connected to some speakers and a head unit so you can test the output. The voltmeter tests the amount of voltage that the amplifier is feeding your subwoofers. The voltage can be converted to wattage using standard physics conversions.

    First connect the volt meter to the speaker outputs on the amplifier. With the volt meter set to AC voltage, turn up the volume on your head unit and watch as the volt reading rises. The meter is gauging the amount of power that is going to the subwoofers. Wait until the voltage meter stops at the peak power for a few seconds. This is the peak voltage rating.

    Once you have the peak voltage rating, enter it into a calculator and multiply the number by itself. For example, if your voltage rating was 30, you would multiply it by 30 to get a total of 900. Now divide this amount by the subwoofer’s ohm load (or impedance). The subwoofer’s impedance rating can usually be found on the subwoofer and is measured in ohms. For example, if you were using a 2 ohm subwoofer, you would divide your total by 2 to get the peak power rating. In our example our total was 900, so dividing this number by 2 would put us at 450 watts of peak power. This means that the amplifier puts out a total maximum power of 450 watts. The RMS is approximately half of this number. So in our example you would divide 450 by 2 to get 225 watts of continuous RMS power. This means your car amplifier can provide your subwoofers with 225 watts on a continual basis. In order to experience optimal performance, you should find subwoofers that can handle around 225 watts of RMS power.

    Below are the calculations for your reference:

    (AC Voltage x AC Voltage) / Impedance of the Subwoofer = Peak Power produced by the amplifier

    Peak Power / 2 = RMS Power produced by amplifier

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    How to Bridge an Amplifier

    amp-bridge

    Bridging refers to combining two (four) channels of an amplifier into one (two) channel(s) with twice the voltage. A two channel amp can be bridged to one channel, and a four channel amp into two channels. Bridging the channels increases the power output. An amplifier is usually bridged to combine two channels to power one subwoofer, or to combine four channels into powering two subwoofers.  To clarify, you cannot bridge a monoblock amplifier! The definition of bridging is combining two or more channels, and a monoblock amplifier has only one channel. You will need opposing channels in order to bridge the amplifier. In technical terms, you using a low source impedance to drive a large load impedance, which results in maximum voltage transfer.

    Bridgeable amplifiers are designed with an inverted channel for bridging purposes. The inverted channel produces voltage that is generated at the opposite polarity of the regular, un-bridged channel. Bridging an amplifier produces almost four times the amount of power as it would in an un-bridged status.

    Before you attempt to bridge an amplifier, there are certain conditions you must keep in mind. Only bridge an amplifier that can handle the increased power load. Do not bridge an amp that will be unstable at the bridged load, or if the speakers cannot handle the increased power. Always check your product’s paperwork and diagrams before you bridge your amplifier. Using your amplifier’s paperwork is the easiest way to figure out how to bridge your amplifier.

    Unless otherwise stated, all multi-channel amplifiers have a minimum bridged stability that is higher than the minimum stated impedance from one of its channels. For example, a 2 channel amplifier that is 1 ohm stable per channel would have a minimum impedance of 2 ohms when bridged. In reality, most amps are only stable at a 4 ohm load in mono/bridged configuration.

    Amp Bridging

    To bridge your amplifier, locate the amp terminals. For a 2-channel amplifier, you will see four terminals. A positive and a negative terminal for channel one, and likewise for channel two. If you are bridging this 2-channel amp to one subwoofer, you will connect one piece of speaker wire from the positive terminal of channel 1 to the speaker’s positive terminal. Next connect a separate cut of speaker wire to the negative terminal of channel 2 to the speaker’s negative terminal.

    That’s the gist of amplifier bridging. If you are totally inexperienced, ask a knowledeable friend to help guide you.

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    How To Choose An Amp

    brx12001d

    An amplifier modulates power from your car battery to supply your car stereo system with the juice it needs to keep the bass booming and the speakers crooning. There are many aspects to consider when selecting an amplifier for your car stereo system. Here is quick list of what you should keep in mind.

    • First Choose your Speakers and Subs

    Once you have settled on what types of speakers and subwoofers you will be running, you will now be able to choose an amp based on the speaker’s power ratings, impedance, efficiency, and voice coil configurations. This will help you figure out how much power you will need from your car amplifier and in planning how you will go about wiring your amp. For example, if you are only choosing one subwoofer, you will want to know if you can bridge the 2-channel amp that you have in mind.

    • A Powerful Amp Will “Amp” Up Your System

    The higher the impedance of the speakers, the higher the impedance you must run the amp at. Along with that, the higher the impedance an amplifier runs at, the lesser the amount of power generated by the amp. Many amplifiers can run at either 2 ohm or 4 ohm loads, but some are stable at 1 ohm loads for optimal RMS performance.

    Be sure to pay attention to the RMS power ratings, which refers to the amount of continuous power produced by an amplifier. Ignore the peak power ratings, these ratings are totally insignificant when trying to match up an amplifier with subs and speakers.

    • Efficiency Matters

    The ratio of power output to power input, expressed as a percentage. For example, consider a Class A amplifier that produces 100 watts of power output from 200 watts of power input. This amplifier is rated at 50% efficiency.

    To measure an amplifier’s efficiency, you need to know the power output and input levels, the car battery voltage, and the amp fuse size (measured in amperes). In the example above, assume the Class A amp uses a fuse size that is 10A and the car battery voltage is 14.4 volts. Multiplying 14.4v times 10A gives 144 watts in. 100 watts out divided by 144 watts in equals .6944. This means an amplifier with a 10A fuse and 14.4 v battery will need to be rated at 70% efficiency to produce 100 watts.

    Since this is way beyond the realm of possibility, you will need to find an amplifier with a higher fuse rating to produce 100 watts. For example, take the same Class A amplifier above except imagine it with a 15A fuse instead of a 10A. 15A multiplied by 14.4v equals 216 watts in. 100 watts divided by 216 equals .4629, which means a Class A amp with a more realistic requirement of only 47% efficiency is needed to produce 100 watts.

    Remember, Class A Amplifiers only offer a theoretical maximum of 50% efficiency. Class B amplifiers have a maximum theoretical efficiency of 78.5%, and Class D amps can operate at levels between 80-95% efficiency. This is important to note when considering the fuse sizes and power ratings of an amplifier.

    • Heat Sink Keeps Amplifier Temperature in Check

    Consider the size and quality of the heat sink. The heat sink is used to dissipate heat and to keep the amplifier running efficiently. A heavy duty heat sink will provide better thermal stability. To further help prevent the amplifier from overheating, check out amps with cooling fans.

    • Damping Factor: Control Your Speakers

    The damping factor measures how well the amp will control unwanted movement of the speaker coil. The higher the damping factor, the better the amplifier will be in controlling the speaker’s undesired movements. To calculate damping factor, divide the speaker’s impedance by the amp’s output impedance.

    • Speaker Level Inputs and RCA Terminals

    An amplifier with speaker level inputs will allow you to run your amplifier from a factory receiver. Additionally, if you have no remaining preamp outputs left on your aftermarket car receiver, you can use the amp’s speaker level inputs. You want to make sure the speaker level inputs and the RCA connection terminals are secure, since your amp will have to survive the bumps and dips in the road.

    • Price

    Make sure you plan your budget ahead of time. To install your amplifier, you will need amplifier wiring kits, and other accessories. You may also consider purchasing digital capacitors or other items to keep your system running at full throttle. We can help you choose which amplifier is right for you. Give us a call at 1-877-289-7664.

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