Amp question
#1
11-18-2009, 09:21 PM
Amp question
Im planning on replacing the entire speaker system in my car and i was wondering how hard it is to replace the stock amp in the trunk with an after market?? is it a simple unplug and plug into the new one or is it extremely complicated??
#2
11-18-2009, 09:49 PM
It is definitely not plug and play. You'll need to at the very least run new main power and ground wires. Are you replacing the factory headunit as well? If so, you'll need to run new RCAs and a remote wire. Then depending on how much power you want to run, you might need to run new speaker wires from the amp to your speakers.
Sounds like a lot to do, and it is kinda, but it's not very hard. I wouldn't call it extremely complicated. Mostly just time consuming.
Sounds like a lot to do, and it is kinda, but it's not very hard. I wouldn't call it extremely complicated. Mostly just time consuming.
#3
11-18-2009, 10:35 PM
An aftermarket amplifier is a pretty complex thing to do if you're not used to basic electronic concepts. If you're fairly intelligent and can follow some simple instructions then you'll be fine. If it's your first time, expect the hardest part to be trying to find a hole in your firewall to get a power wire through.
Aftermarket amplifiers are more power hungry than stock systems (most likely why you want to upgrade). Like Dbl_D718 was saying, you'll have to run a direct heavy gauge wire from your battery through your engine compartment, through the firewall, under your carpetting near your door sills, and underneath the back seat to get into the trunk. Your new amp will not have a matching mounting location, so you'll have to figure out a place for your amp to "live," then make sure you have a solid place to ground the power connection to (same gauge wire as the power cable coming the battery, only this is bolted to the chassis, and generally bolted to bare metal no more than two feet away from the amp). After you've got power running to it, and it's able to turn on, you'll have to wire what they call a "Remote" wire to it (don't worry, these things are all labeled very conspicuously on the amp). The remote wire has to be cirectly connected to the back of your stereo (also known as a deck), so you'll have to uninstall your deck to crimp this wire and run it from there to the trunk. If you are replacing the deck with an aftermarket one then you'll want to run another set of wires to the trunk from the deck called RCA cables. These are what carries the music to the amp. If you're not running RCA's you can clip your stock speaker wires and re-route them to the amp, then back to the speaker from the amp to pass the signal to teh speakers. They call this "speaker-level input."
It all sounds pretty hard at first, especially when you don't have someone to show you the ropes. If you've got a friend that does some car stereo stuff they'll probably be able to introduce you to the concept of car stereo installation. a good guideline for help is http://the12volt.com
Aftermarket amplifiers are more power hungry than stock systems (most likely why you want to upgrade). Like Dbl_D718 was saying, you'll have to run a direct heavy gauge wire from your battery through your engine compartment, through the firewall, under your carpetting near your door sills, and underneath the back seat to get into the trunk. Your new amp will not have a matching mounting location, so you'll have to figure out a place for your amp to "live," then make sure you have a solid place to ground the power connection to (same gauge wire as the power cable coming the battery, only this is bolted to the chassis, and generally bolted to bare metal no more than two feet away from the amp). After you've got power running to it, and it's able to turn on, you'll have to wire what they call a "Remote" wire to it (don't worry, these things are all labeled very conspicuously on the amp). The remote wire has to be cirectly connected to the back of your stereo (also known as a deck), so you'll have to uninstall your deck to crimp this wire and run it from there to the trunk. If you are replacing the deck with an aftermarket one then you'll want to run another set of wires to the trunk from the deck called RCA cables. These are what carries the music to the amp. If you're not running RCA's you can clip your stock speaker wires and re-route them to the amp, then back to the speaker from the amp to pass the signal to teh speakers. They call this "speaker-level input."
It all sounds pretty hard at first, especially when you don't have someone to show you the ropes. If you've got a friend that does some car stereo stuff they'll probably be able to introduce you to the concept of car stereo installation. a good guideline for help is http://the12volt.com
#4
11-19-2009, 03:36 PM
To add on his question...if an amp has an 600 rms...will it affect a 500 rms sub? should i pay attention to peak power rather then rms?
#5
11-19-2009, 05:43 PM
Power and loudness in the real world
Perceived "loudness" varies logarithmically with output power (other inversely proportionate factors are; frequency, number and material of objects through which the sound waves must travel, as well as distance between source and receiver) a given change in output power produces a much smaller change in perceived loudness. Consequently it is useful and accurate to express perceived loudness in the logarithmic decibel (dB) scale; a change of 1 dB, which corresponds to a 25.9% change in power level, is considered to be the smallest change in sound power level perceivable by the average human ear under idealized test conditions. An increase/decrease of 3 dB corresponds to a doubling/halving of power and distance of average perceivability. The sensitivity of loudspeakers, rather than merely the often-quoted power-handling capacity, is important. Many high quality domestic speakers have a sensitivity of 84 dB for 1 W at 1 meter, but professional speakers can have a figure of 90 dB for 1 W or even 100 dB (especially for some large-coned woofers). I.E., An '84 dB' source "speaker" would require a 400-watt amplifier (assuming it didn't burn out) to produce the same audio energy as a '90 dB' source being driven by a 100-watt amplifier, or a '100 dB' source being driven by a 9.92 watt amplifier(though in practice modern sub-woofers are often driven by high power amps to overcome the restriction of a small enclosure through the use of equalization). This does not mean a bigger speaker can produce more sound with less overall power. Just that a larger speaker can typically handle more initial power and so requires less amplification to achieve the same high level of output. This means using a speaker with a higher dB rating can be more advantageous as many amplifiers inevitably produce a certain amount of distortion for a given level of amplification. So, (more speaker)+(less amp.)=(same "loudness")+(less distortion).
A better measure of the 'power' of a system is therefore a plot of maximum loudness before clipping, in dB SPL, at the listening position intended, over the audible frequency spectrum. A good system should be capable of generating higher sound levels below 100 Hz before clipping, as the human ear is less sensitive to low frequencies, as indicated by Equal-loudness contours.
[edit] 'Music power' — the real issues
The term "Music Power" has been used in relation to both amplifiers and loudspeakers with some validity. When live music is recorded without amplitude compression or limiting, the resulting signal contains brief peaks of very much higher amplitude (20 dB or more) than the mean, and since power is proportional to the square of signal voltage their reproduction would require an amplifier capable of providing brief peaks of power around a hundred times greater than the average level. Thus the ideal 100-watt audio system would need to be capable of handling brief peaks of 10,000 watts in order to avoid clipping (see Programme levels). Most loudspeakers are in fact capable of withstanding peaks of several times their continuous rating (though not a hundred times), since thermal inertia prevents the voice coils from burning out on short bursts. It is therefore acceptable, and desirable, to drive a loudspeaker from a power amplifier with a higher continuous rating several times the steady power that the speaker can withstand, but only if care is taken not to overheat it; this is difficult, especially on modern recordings which tend to be heavily compressed and so can be played at high levels without the obvious distortion that would result from an uncompressed recording when the amplifier started clipping.
An amplifier can be designed with an audio output circuitry capable of generating a certain power level, but with a power supply unable to supply sufficient power for more than a very short time, and with heat sinking that will overheat dangerously if full output power is maintained for long. This makes good technical and commercial sense, as the amplifier can handle music with a relatively low mean power, but with brief peaks; a high 'music power' output can be advertised (and delivered), and money saved on the power supply and heat sink. Program sources that are significantly compressed are more likely to cause trouble, as the mean power can be much higher for the same peak power. Circuitry which protects the amplifier and power supply can prevent equipment damage in the case of sustained high power operation.
More sophisticated equipment usually used in a professional context has advanced circuitry which can handle high peak power levels without delivering more average power to the speakers than they and the amplifier can handle safely.
[edit] Power handling in 'active' speakers
Active speakers comprise two or three speakers per channel, each fitted with its own amplifier, and preceded by an electronic crossover filter to separate the low-level audio signal into the frequency bands to be handled by each speaker. This approach enables complex active filters to be used on the low level signal, without the need to use passive crossovers of high power-handling capability but limited rolloff and with large and expensive inductors and capacitors. An additional advantage is that peak power handling is greater if the signal has simultaneous peaks in two different frequency bands. A single amplifier has to handle the peak power when both signal voltages are at their crest; as power is proportional to the square of voltage, the peak power when both signals are at the same peak voltage is proportional to the square of the sum of the voltages. If separate amplifiers are used, each must handle the square of the peak voltage in its own band. For example, if bass and midrange each has a signal corresponding to 10 W of output, a single amplifier capable of handling a 40 W peak would be needed, but a bass and a treble amplifier each capable of handling 10 W would be sufficient. This is relevant when peaks of comparable amplitude occur in different frequency bands, as with wideband percussion and high-amplitude bass notes.
For most audio applications more power is needed at low frequencies. This requires a high-power amplifier for low freqencies (e.g., 200 watts for 20-200 Hz band), lower power amplifier for the midrange (e.g., 50 watts for 200 to 1000 Hz), and even less the high end (e.g. 5 watts for 1000-20000 Hz). Proper design of a bi/tri amplifier system requires a study of driver (speaker) frequency response and sensitivities to determine optimal crossover frequencies and power amplifier powers.
Peak vs RMS: You know that peak power is 2*RMS power. If a speaker is actually capable of handling 150 watts of peak power it would only be rated to handle 75 watts RMS. If a speaker is rated to handle 150 watts 'music power', it may mean that the speaker will take only very short bursts of power approaching 150 watts RMS. Even if there are two speakers from different manufacturers which have the same power ratings, one of the manufacturers may be more conservative in their ratings than the other manufacturer. The more conservatively rated speaker would be more likely to handle its rated power. Bottom line, beware of power ratings on speakers. Knowing that some manufacturers are less than honest in their power ratings, will likely help you to make better decisions when buying speakers.
Amplifiers and Speakers: Many people ask the question... Can my speakers handle this amplifier or will this amplifier blow my speakers. Well, the truth is that any speaker can be driven by any amplifier. The only time that there will be a problem is when the person operating the system becomes abusive. Most people (and I do mean most) drive their amplifiers well into clipping. I know what your thinking... I never drive my amp into clipping. Well, you must be one of the very few. Generally speaking, if you have friends who are impressed by high volume, you drive your system into clipping.
Clipping: Unless you listen to your system from a distance, you cannot hear clipping distortion until it reaches extreme levels. I know you are thinking that you can probably hear even .5% distortion levels in music. Well, if you were listening to a test tone in an anechoic chamber at an 80 dB SPL on your best day, MAYBE. But... due to the design of the human ear, you cannot hear minimal distortion levels at higher SPLs. At any SPL above approximately 90 dB, your ears overload and cannot accurately convert the sound pressure to the electrical impulses which are sent to your brain. Since most amplifiers are capable of producing more than one watt of power and most speakers will produce at least 88 dB of sound pressure at one watt of input at one meter, it is very difficult to hear minimal distortion at 10, 20, 50 or more watts. If you honestly want to see if you're driving your system into clipping, play some familiar music at the highest volume that you would play it (when you are showing off for your friends) and step way away from you vehicle (with the doors open of course). You may have to turn off your bass amplifiers to listen for distortion in your 'highs'. I think you will be surprised at the levels of distortion that you hear. Now, be honest if you do this little experiment.
Bottom Line: No one can tell you if you will blow your speakers with a given amplifier. They may be able to tell you whether or not a pair of speakers will be able to handle a given amount of continuous RMS power. But... since they don't know your listening habits or your ability to hear (or even be concerned about) distortion, they (in my opinion) cannot actually tell you if a given amplifier (with you at the volume control) will blow your speakers.
(Per Wikipedia)
Perceived "loudness" varies logarithmically with output power (other inversely proportionate factors are; frequency, number and material of objects through which the sound waves must travel, as well as distance between source and receiver) a given change in output power produces a much smaller change in perceived loudness. Consequently it is useful and accurate to express perceived loudness in the logarithmic decibel (dB) scale; a change of 1 dB, which corresponds to a 25.9% change in power level, is considered to be the smallest change in sound power level perceivable by the average human ear under idealized test conditions. An increase/decrease of 3 dB corresponds to a doubling/halving of power and distance of average perceivability. The sensitivity of loudspeakers, rather than merely the often-quoted power-handling capacity, is important. Many high quality domestic speakers have a sensitivity of 84 dB for 1 W at 1 meter, but professional speakers can have a figure of 90 dB for 1 W or even 100 dB (especially for some large-coned woofers). I.E., An '84 dB' source "speaker" would require a 400-watt amplifier (assuming it didn't burn out) to produce the same audio energy as a '90 dB' source being driven by a 100-watt amplifier, or a '100 dB' source being driven by a 9.92 watt amplifier(though in practice modern sub-woofers are often driven by high power amps to overcome the restriction of a small enclosure through the use of equalization). This does not mean a bigger speaker can produce more sound with less overall power. Just that a larger speaker can typically handle more initial power and so requires less amplification to achieve the same high level of output. This means using a speaker with a higher dB rating can be more advantageous as many amplifiers inevitably produce a certain amount of distortion for a given level of amplification. So, (more speaker)+(less amp.)=(same "loudness")+(less distortion).
A better measure of the 'power' of a system is therefore a plot of maximum loudness before clipping, in dB SPL, at the listening position intended, over the audible frequency spectrum. A good system should be capable of generating higher sound levels below 100 Hz before clipping, as the human ear is less sensitive to low frequencies, as indicated by Equal-loudness contours.
[edit] 'Music power' — the real issues
The term "Music Power" has been used in relation to both amplifiers and loudspeakers with some validity. When live music is recorded without amplitude compression or limiting, the resulting signal contains brief peaks of very much higher amplitude (20 dB or more) than the mean, and since power is proportional to the square of signal voltage their reproduction would require an amplifier capable of providing brief peaks of power around a hundred times greater than the average level. Thus the ideal 100-watt audio system would need to be capable of handling brief peaks of 10,000 watts in order to avoid clipping (see Programme levels). Most loudspeakers are in fact capable of withstanding peaks of several times their continuous rating (though not a hundred times), since thermal inertia prevents the voice coils from burning out on short bursts. It is therefore acceptable, and desirable, to drive a loudspeaker from a power amplifier with a higher continuous rating several times the steady power that the speaker can withstand, but only if care is taken not to overheat it; this is difficult, especially on modern recordings which tend to be heavily compressed and so can be played at high levels without the obvious distortion that would result from an uncompressed recording when the amplifier started clipping.
An amplifier can be designed with an audio output circuitry capable of generating a certain power level, but with a power supply unable to supply sufficient power for more than a very short time, and with heat sinking that will overheat dangerously if full output power is maintained for long. This makes good technical and commercial sense, as the amplifier can handle music with a relatively low mean power, but with brief peaks; a high 'music power' output can be advertised (and delivered), and money saved on the power supply and heat sink. Program sources that are significantly compressed are more likely to cause trouble, as the mean power can be much higher for the same peak power. Circuitry which protects the amplifier and power supply can prevent equipment damage in the case of sustained high power operation.
More sophisticated equipment usually used in a professional context has advanced circuitry which can handle high peak power levels without delivering more average power to the speakers than they and the amplifier can handle safely.
[edit] Power handling in 'active' speakers
Active speakers comprise two or three speakers per channel, each fitted with its own amplifier, and preceded by an electronic crossover filter to separate the low-level audio signal into the frequency bands to be handled by each speaker. This approach enables complex active filters to be used on the low level signal, without the need to use passive crossovers of high power-handling capability but limited rolloff and with large and expensive inductors and capacitors. An additional advantage is that peak power handling is greater if the signal has simultaneous peaks in two different frequency bands. A single amplifier has to handle the peak power when both signal voltages are at their crest; as power is proportional to the square of voltage, the peak power when both signals are at the same peak voltage is proportional to the square of the sum of the voltages. If separate amplifiers are used, each must handle the square of the peak voltage in its own band. For example, if bass and midrange each has a signal corresponding to 10 W of output, a single amplifier capable of handling a 40 W peak would be needed, but a bass and a treble amplifier each capable of handling 10 W would be sufficient. This is relevant when peaks of comparable amplitude occur in different frequency bands, as with wideband percussion and high-amplitude bass notes.
For most audio applications more power is needed at low frequencies. This requires a high-power amplifier for low freqencies (e.g., 200 watts for 20-200 Hz band), lower power amplifier for the midrange (e.g., 50 watts for 200 to 1000 Hz), and even less the high end (e.g. 5 watts for 1000-20000 Hz). Proper design of a bi/tri amplifier system requires a study of driver (speaker) frequency response and sensitivities to determine optimal crossover frequencies and power amplifier powers.
Peak vs RMS: You know that peak power is 2*RMS power. If a speaker is actually capable of handling 150 watts of peak power it would only be rated to handle 75 watts RMS. If a speaker is rated to handle 150 watts 'music power', it may mean that the speaker will take only very short bursts of power approaching 150 watts RMS. Even if there are two speakers from different manufacturers which have the same power ratings, one of the manufacturers may be more conservative in their ratings than the other manufacturer. The more conservatively rated speaker would be more likely to handle its rated power. Bottom line, beware of power ratings on speakers. Knowing that some manufacturers are less than honest in their power ratings, will likely help you to make better decisions when buying speakers.
Amplifiers and Speakers: Many people ask the question... Can my speakers handle this amplifier or will this amplifier blow my speakers. Well, the truth is that any speaker can be driven by any amplifier. The only time that there will be a problem is when the person operating the system becomes abusive. Most people (and I do mean most) drive their amplifiers well into clipping. I know what your thinking... I never drive my amp into clipping. Well, you must be one of the very few. Generally speaking, if you have friends who are impressed by high volume, you drive your system into clipping.
Clipping: Unless you listen to your system from a distance, you cannot hear clipping distortion until it reaches extreme levels. I know you are thinking that you can probably hear even .5% distortion levels in music. Well, if you were listening to a test tone in an anechoic chamber at an 80 dB SPL on your best day, MAYBE. But... due to the design of the human ear, you cannot hear minimal distortion levels at higher SPLs. At any SPL above approximately 90 dB, your ears overload and cannot accurately convert the sound pressure to the electrical impulses which are sent to your brain. Since most amplifiers are capable of producing more than one watt of power and most speakers will produce at least 88 dB of sound pressure at one watt of input at one meter, it is very difficult to hear minimal distortion at 10, 20, 50 or more watts. If you honestly want to see if you're driving your system into clipping, play some familiar music at the highest volume that you would play it (when you are showing off for your friends) and step way away from you vehicle (with the doors open of course). You may have to turn off your bass amplifiers to listen for distortion in your 'highs'. I think you will be surprised at the levels of distortion that you hear. Now, be honest if you do this little experiment.
Bottom Line: No one can tell you if you will blow your speakers with a given amplifier. They may be able to tell you whether or not a pair of speakers will be able to handle a given amount of continuous RMS power. But... since they don't know your listening habits or your ability to hear (or even be concerned about) distortion, they (in my opinion) cannot actually tell you if a given amplifier (with you at the volume control) will blow your speakers.
(Per Wikipedia)
#6
11-20-2009, 01:40 AM
Wow, that's a long post lol.
A 600 watt rms amp is perfect for a 500 watt rms sub in my opinoin. Search the web to learn how to properly set the gain on your amp and you'll be golden.
Never pay attention to peak ratings. They're practically meaningless, they just give a bigger number for marketing reasons.
A 600 watt rms amp is perfect for a 500 watt rms sub in my opinoin. Search the web to learn how to properly set the gain on your amp and you'll be golden.
Never pay attention to peak ratings. They're practically meaningless, they just give a bigger number for marketing reasons.
#7
11-20-2009, 07:00 AM
Wow, that's a long post lol.
A 600 watt rms amp is perfect for a 500 watt rms sub in my opinoin. Search the web to learn how to properly set the gain on your amp and you'll be golden.
Never pay attention to peak ratings. They're practically meaningless, they just give a bigger number for marketing reasons.
A 600 watt rms amp is perfect for a 500 watt rms sub in my opinoin. Search the web to learn how to properly set the gain on your amp and you'll be golden.
Never pay attention to peak ratings. They're practically meaningless, they just give a bigger number for marketing reasons.
I only get high end stuff when I build my systems, so it takes a little more though process to exactly get my number figured out. My sub is 2000w RMS with a 2500w max. Pushing it I've got a 250w high current amp bridged to 1ohm pushing 2000w rms and 2800w max, so i've gotta watch my gain.
#8
11-20-2009, 09:35 AM
The max rating is not the power an amp will put out when it's playing at full volume. At full volume, an amp will be putting out about its rms rating. The max ratings aren't anything usefull with amps, and most of the time aren't usefull with subs either. However, some [good] sub manufacturers give a "max" rating, rating the sub for what it can thermally handle in a short burp at a sound competition.
#9
11-21-2009, 01:27 PM
This is what I've always turned to when using max rating a for a guideline. Temporary hold at full gain for a brief moment.
#10
11-21-2009, 02:47 PM
ok cool info...so i got this kenwood excelon mono...in it has 2 speaker inputs...which do i use when im runnin dual 4 ohm 12's wired in parallel