Spec_R
20-09-2006, 03:00 PM
sorry i have to make anotther thread as the first one it didn't let me add anymore to it.
What is THD?
is for "total harmonic distortion", and is a measure of the how much a certain device may distort a signal. These figures are usually given as percentages. It is believed that THD figures below
approximately 0.1% are inaudible. However, it should be realized that distortion adds, so that if a head unit, equalizer, signal processor, crossover, amplifier and speaker are all rated at "no greater than 0.1%THD", together, they could produce 0.6%THD, which could be noticeable in the output.
What is OHM?
is a measure of resistance and impedance, which tells you how much a device will resist the flow of current in a circuit. For example, if the same signal at the same voltage is sent into two
speakers - one of which is nominally rated at 4 ohms of impedance, the other at 8 ohms impedance - twice as much current will flow through the 4 ohm speaker as the 8 ohm speaker, which requires twice as much power, since power is proportional to current.
What is a line driver?signal booster?
A line driver is a device that amplifies a signal, such as the low-level signal output from a head unit. Line drivers are made to amplify the line level signal to as much as 10 volts or higher. This, of course, is useless unless the receiving end can handle 10 volts as input. To solve this problem, there are line receivers which bring the line level voltage down from 10 volts or more to about 1 volt. Usually, the line driver and receiver are placed as close to the sending signal source and destination as possible, to minimize noise pick up.
Amplifier Specification
"Frequency response" refers to the range of frequencies which the amplifier can reproduce within a certain power range, usually +/-3dB.
"Continuous power output(RMS)" is the power output of the amplifier into one channel into a certain load (usually four ohms) below a certain distortion level (usually at most 1%THD) at a certain frequency (usually 1kHz). A complete power specification should include all ofthis information, e.g. "20W/ch into 4 ohms at < 0.03%THD at 1kHz" although this can also be stated as (and be assumed equivalent to) "20W/ch at < 0.03%THD". The amplifier should also be able to sustain this power level for long periods of time without difficulties such as overheating.
"Peak power output(MAX)" is the power output of the amplifier into one channel into a certain load (usually four ohms) below a certain distortion level (usually much higher than the continuous rating level) at a certain frequency (usually 1kHz). A complete power specification should include all of this information, e.g. "35W/ch into 4 ohms at <10.0%THD at 1kHz" although this can also be stated as (and be assumedequivalent to) "35Wch at < 10.0%THD". warning: some manufacturers will state the "peak power output" rating by includingthe amount of power which can be drawn from "headroom", which means power supply capacitors. They usually will not tell you this in the specification, however; indeed, they tend to prominently display the figure in big, bold letters on the front of the box, such as "MAXIMUM 200W PER CHANNEL!!!" when the continuous rating is 15W/ch and the unit has a 5A fuse. This is the same for amplifiers and speakers
"Damping factor" represents the ratio of the load being driven (that is, the speaker - usually four ohms) to the output impedance of the amplifier (that is, the output impedance of the transistors which drive the speakers). The lower the output impedance, the higher the damping factor. Higher damping factors indicate a greater ability to help control the motion of the cone of the speaker which is being driven. When this motion is tightly controlled, a greater transient response is evident in the system, which most people refer to as a "tight" or "crisp" sound. Damping factors above 100 are generally regarded as good.
"Signal to Noise" or "S/N" is the ratio, usually expressed in decibels, of the amount of true amplified output of the amplifier to the amount of extraneous noise injected into the signal. S/N ratios above 90 to 95dB are generally regarded as good.
What does brigding an amp mean?
"Bridging" refers to taking two channels of an amplifier and combining them to turn the amplifier into a one channel amplifier thus increase power output.
Can i brigde 4 channel head unit?
Generally, NO. Unless the manuals that came with your head unit specifically state that your head unit can be bridged, then do NOTattempt it - this could destroy the head unit's internal amplifier.
How do i set the gain on my amp?
The best way to do this is with a test tone and an oscilloscope. Here is the manual way works just as well
Note:if you dont want to disconnect the input signal, you can just use the "fader" function on ur headunit
1. Disconnect all signal inputs to the amp (RCA cable)
2. Turn all sensitivity adjustments as low as possible
3. Turn head unit on to around 90% volume (not 100% or else
you'll have head unit distortion in there - unless you've got
a good head unit) with some music with which you're familiar,
and with EQ controls set to normal listening positions
4. Plug in one channel's input to the amp
5. Slowly turn that channel's gain up until you just start to
notice distortion on the output
6. Turn it down just a wee little bit
7. Disconnect current input
8. Repeat steps 4-7 with each input on your amp
9. Turn off head unit
10. Plug in all amp inputs, and you're done
Note:that if you are paralleling multiple speakers on a single amp
output, you need to set the gains with all of the speakers in place, since they will be affecting the power and distortion characteristics of the channel as a whole.
Speaker Specification:
"Input sensitivity" is the SPL the driver will produce given one watt of power as measured from one meter away given some input frequency (usually 1kHz unless otherwise noted on the speaker). Typical sensitivities for car audio speakers are around 90dB/Wm. Some subwoofers and piezo horns claim over 100dB/Wm. However, some manufacturers do not use true 1W tests, especially on low impedance subwoofers. Rather, they use a constant voltage test which produces more impressive sensitivity ratings.
"Frequency response" in a speaker refers to the range of frequencies which the speaker can reproduce within a certain power range, usually +/-3dB.
"Impedance" is the impedance of the driver, typically 4 ohms, although some subwoofers are 8 ohms, even 2ohms (refer to what is ohm? at the top of page)
"Nominal power handling(RMS)" is the continuous power handling of the driver. This figure tells you how much power you can put into the driver for very long periods of time without having to worry aboutbreaking the suspension, overheating the voice coil, or other nasty things.
"Peak power handling(MAX)" is the maximum power handling of the driver. This figure tells you how much power you can put into the driver forvery brief periods of time without having to worry about destroying it.
How do I wire speakers "in series" and "in parallel?"
Wiring speakers in series involves connecting at least two speakers so that the first speaker's positive lead is connected to the amplifier's positive terminal, and the negative lead is connected to the positive lead of the second speaker. If there is a third speaker, its positive lead will be connected to the second speaker's negative lead ... and so on. The last speaker in the chain will have its negative lead connected to the amplifier's negative terminal.
Speakers that are wired in parallel are all connected to the positive and negative terminals of the amplifier. So, when two speakers are wired in parallel, you'll connect each speaker's positive lead to the amplifier's positive terminal, and you'll connect each speaker's negative lead to the amplifier's negative terminal.
Be careful when wiring multiple speakers in parallel or series so that
you do not exceed your amplifier's rating. To calculate the effective
impedance of a number of speakers, use the following formulas:
Series Connections:
Z(t) = Z(1) + Z(2) + Z(3) + ... + Z(n)
That is, add up all of the impedances for each speaker to
get the total impedance. For example, with 3 4-ohm speaker
in series, the total impedance is 4 + 4 + 4 = 12 ohms.
Parallel Connections:
1/Z(t) = 1/Z(1) + 1/Z(2) + 1/Z(3) + ... + 1/Z(n)
That is, add up the inverse of the impedance of each
speaker and invert the sum to get the total impedance. For
example, with 3 4-ohm speakers in parallel, the total
impedance is 1 / ( 1/4 + 1/4 + 1/4) = 1 / (3/4) = 1.33 ohms.
What is THD?
is for "total harmonic distortion", and is a measure of the how much a certain device may distort a signal. These figures are usually given as percentages. It is believed that THD figures below
approximately 0.1% are inaudible. However, it should be realized that distortion adds, so that if a head unit, equalizer, signal processor, crossover, amplifier and speaker are all rated at "no greater than 0.1%THD", together, they could produce 0.6%THD, which could be noticeable in the output.
What is OHM?
is a measure of resistance and impedance, which tells you how much a device will resist the flow of current in a circuit. For example, if the same signal at the same voltage is sent into two
speakers - one of which is nominally rated at 4 ohms of impedance, the other at 8 ohms impedance - twice as much current will flow through the 4 ohm speaker as the 8 ohm speaker, which requires twice as much power, since power is proportional to current.
What is a line driver?signal booster?
A line driver is a device that amplifies a signal, such as the low-level signal output from a head unit. Line drivers are made to amplify the line level signal to as much as 10 volts or higher. This, of course, is useless unless the receiving end can handle 10 volts as input. To solve this problem, there are line receivers which bring the line level voltage down from 10 volts or more to about 1 volt. Usually, the line driver and receiver are placed as close to the sending signal source and destination as possible, to minimize noise pick up.
Amplifier Specification
"Frequency response" refers to the range of frequencies which the amplifier can reproduce within a certain power range, usually +/-3dB.
"Continuous power output(RMS)" is the power output of the amplifier into one channel into a certain load (usually four ohms) below a certain distortion level (usually at most 1%THD) at a certain frequency (usually 1kHz). A complete power specification should include all ofthis information, e.g. "20W/ch into 4 ohms at < 0.03%THD at 1kHz" although this can also be stated as (and be assumed equivalent to) "20W/ch at < 0.03%THD". The amplifier should also be able to sustain this power level for long periods of time without difficulties such as overheating.
"Peak power output(MAX)" is the power output of the amplifier into one channel into a certain load (usually four ohms) below a certain distortion level (usually much higher than the continuous rating level) at a certain frequency (usually 1kHz). A complete power specification should include all of this information, e.g. "35W/ch into 4 ohms at <10.0%THD at 1kHz" although this can also be stated as (and be assumedequivalent to) "35Wch at < 10.0%THD". warning: some manufacturers will state the "peak power output" rating by includingthe amount of power which can be drawn from "headroom", which means power supply capacitors. They usually will not tell you this in the specification, however; indeed, they tend to prominently display the figure in big, bold letters on the front of the box, such as "MAXIMUM 200W PER CHANNEL!!!" when the continuous rating is 15W/ch and the unit has a 5A fuse. This is the same for amplifiers and speakers
"Damping factor" represents the ratio of the load being driven (that is, the speaker - usually four ohms) to the output impedance of the amplifier (that is, the output impedance of the transistors which drive the speakers). The lower the output impedance, the higher the damping factor. Higher damping factors indicate a greater ability to help control the motion of the cone of the speaker which is being driven. When this motion is tightly controlled, a greater transient response is evident in the system, which most people refer to as a "tight" or "crisp" sound. Damping factors above 100 are generally regarded as good.
"Signal to Noise" or "S/N" is the ratio, usually expressed in decibels, of the amount of true amplified output of the amplifier to the amount of extraneous noise injected into the signal. S/N ratios above 90 to 95dB are generally regarded as good.
What does brigding an amp mean?
"Bridging" refers to taking two channels of an amplifier and combining them to turn the amplifier into a one channel amplifier thus increase power output.
Can i brigde 4 channel head unit?
Generally, NO. Unless the manuals that came with your head unit specifically state that your head unit can be bridged, then do NOTattempt it - this could destroy the head unit's internal amplifier.
How do i set the gain on my amp?
The best way to do this is with a test tone and an oscilloscope. Here is the manual way works just as well
Note:if you dont want to disconnect the input signal, you can just use the "fader" function on ur headunit
1. Disconnect all signal inputs to the amp (RCA cable)
2. Turn all sensitivity adjustments as low as possible
3. Turn head unit on to around 90% volume (not 100% or else
you'll have head unit distortion in there - unless you've got
a good head unit) with some music with which you're familiar,
and with EQ controls set to normal listening positions
4. Plug in one channel's input to the amp
5. Slowly turn that channel's gain up until you just start to
notice distortion on the output
6. Turn it down just a wee little bit
7. Disconnect current input
8. Repeat steps 4-7 with each input on your amp
9. Turn off head unit
10. Plug in all amp inputs, and you're done
Note:that if you are paralleling multiple speakers on a single amp
output, you need to set the gains with all of the speakers in place, since they will be affecting the power and distortion characteristics of the channel as a whole.
Speaker Specification:
"Input sensitivity" is the SPL the driver will produce given one watt of power as measured from one meter away given some input frequency (usually 1kHz unless otherwise noted on the speaker). Typical sensitivities for car audio speakers are around 90dB/Wm. Some subwoofers and piezo horns claim over 100dB/Wm. However, some manufacturers do not use true 1W tests, especially on low impedance subwoofers. Rather, they use a constant voltage test which produces more impressive sensitivity ratings.
"Frequency response" in a speaker refers to the range of frequencies which the speaker can reproduce within a certain power range, usually +/-3dB.
"Impedance" is the impedance of the driver, typically 4 ohms, although some subwoofers are 8 ohms, even 2ohms (refer to what is ohm? at the top of page)
"Nominal power handling(RMS)" is the continuous power handling of the driver. This figure tells you how much power you can put into the driver for very long periods of time without having to worry aboutbreaking the suspension, overheating the voice coil, or other nasty things.
"Peak power handling(MAX)" is the maximum power handling of the driver. This figure tells you how much power you can put into the driver forvery brief periods of time without having to worry about destroying it.
How do I wire speakers "in series" and "in parallel?"
Wiring speakers in series involves connecting at least two speakers so that the first speaker's positive lead is connected to the amplifier's positive terminal, and the negative lead is connected to the positive lead of the second speaker. If there is a third speaker, its positive lead will be connected to the second speaker's negative lead ... and so on. The last speaker in the chain will have its negative lead connected to the amplifier's negative terminal.
Speakers that are wired in parallel are all connected to the positive and negative terminals of the amplifier. So, when two speakers are wired in parallel, you'll connect each speaker's positive lead to the amplifier's positive terminal, and you'll connect each speaker's negative lead to the amplifier's negative terminal.
Be careful when wiring multiple speakers in parallel or series so that
you do not exceed your amplifier's rating. To calculate the effective
impedance of a number of speakers, use the following formulas:
Series Connections:
Z(t) = Z(1) + Z(2) + Z(3) + ... + Z(n)
That is, add up all of the impedances for each speaker to
get the total impedance. For example, with 3 4-ohm speaker
in series, the total impedance is 4 + 4 + 4 = 12 ohms.
Parallel Connections:
1/Z(t) = 1/Z(1) + 1/Z(2) + 1/Z(3) + ... + 1/Z(n)
That is, add up the inverse of the impedance of each
speaker and invert the sum to get the total impedance. For
example, with 3 4-ohm speakers in parallel, the total
impedance is 1 / ( 1/4 + 1/4 + 1/4) = 1 / (3/4) = 1.33 ohms.