Anyone good with car audio?

[abailey21]

I used too be a big fan of Polk door and deck speakers, maybe look into them?

[Kyoshojoe]

How much spl does a tweeter put out at 130 decibles?how much spl does a 12 put out at 130 decibles?. If you look at the build i linked. The highs pictured are 2 4inch coax and 2 8inch coaxial getting the same power and as a matter of fact on the same channel. Size of speaker cone only really dictates frequency response and mechanical compliance not power handling. 20watts of dc power turns your voice coil into s heating element. 120watts of power clean and your fine. That 50watts of power is going to clip at high volume and send square waves to your little speakers and you will stand a better chance of shorting the coil. Esspecially if the rest of the system is amped and overpowering the fronts so you dont hear em distort. Yes the head unit will run the fronts fine but the amp will be louder and cleaner at higher volume.

[RC10th]

I'll just keep it all seperate, 4 channels, 4 speakers. When I get a sub I'll get a small mono or bridged 2ch for it. I didn't really want that much equip in the trunk but it will do.

Should I trust the Pioneer speakers and stay brand loyal or? I'm sure there are better speakers out there but ? We only really get the major "auto store" brands. Kenwood, Pioneer, Sony, Kicker, Alpine, JVC, Cadence, Audioline.

[Kyoshojoe]

I think you will be happy going one channel per speaker, it will allow you to tune the 4s separately from rears. The pioneer speakers should work good, pioneer makes good quality produucts and should be a good match for the amp. when listening to different speakers its not so much volume you should pay attention to but rather how accurately they reproduce the sound and the nuances of different brands.

[RC10th]

I just find it hard to get over how tinny they were on two different sound boards at two different shops, they had a far less full sound than any of the others. Weather they weren't amped properly or demo radios EQ was off who knows...

I'd rather buy speakers that suit my listening range instead of sounding good flat out.

[Kyoshojoe]

best to listen to what your ears are telling you, all the speakers you listed are good quality names but will sound different. Its best to go with the speaker that sounds good to you.

[RC10th]

I figured out what to do for amps

4 channel amp (760w Max)
Channel "A" to front speakers (60w RMS each)
Channel "B" to rear speakers (60w RMS each)

2 channel amp (900w Max)
RCA split off "B" to power sub (450w RMS bridged)

Both amps will match each other and I'll make a nice board to mount them to.


The sub is rated at 1300w max and 350w nominal. By keeping the gain low will this be safe for the sub? Will the sub overpower the rest of the system?

[teman]

This is my system, it's pretty compact yet plenty loud…

Deck
---------------------------------------------------------
-Alpine CDE-102 (using USB flash)

Front/rear amp speakers
---------------------------------------------------------
-Alpine KTP-445 4 ch amp 45w RMSx4 @ 4 ohms class D (in-dash)
-Boston Acoustics RC420 component Speakers (front) (in-dash)
-Boston Acoustics RC520 component Speakers (rear) (in side panels)

Sub Amp/Speaker
---------------------------------------------------------
-Audiocontrol Overdrive Sub Line Driver (in glovebox)
-Alpine Mono Block MRP-M450 400w @ 2 ohm Class D (under passenger side seat)
-Alpine SWR-1042D (DVC 10") 400w RMS - 2ohms (in trunk)

[Jim85IROC]

What I would do is for now, run all 4 speakers individually on the 4 channels of the amplifier. When you get a sub down the road, you can either buy a powered sub, buy a separate amplifier for the sub, or at that time, switch the rear speakers back to head unit power, and bridge the 2 channels of the amp that used to run your rear speakers to power the sub(s). This is the approach that I typically take. My rationale is that in a 4 channel sub-less system, the rear speakers are usually necessary to fill in the low bass, because they're usually larger than the fronts, and even if they're not, without a sub, you need all the help you can get with bass. Once you've got the bass handled by a sub, your rear speakers don't do much other than provide a little rear fill. If you run them as loud as the front speakers, you lose the proper stereo image. Because of this, I devote my power to my fronts and my sub, and if I run rears at all, it's just off head unit power.

[Kyoshojoe]

Sorry for the novel, you can skip the green as they are basically Wiki definitions if you want, but I wanted to have a basis for what music is.

A sound wave is the pattern of disturbance caused by the movement of energy traveling through a medium (such as air, water, or any other liquid or solid matter) as it propagates away from the source of the sound. The source is some object that causes a vibration, such as a ringing telephone, or a person's vocal chords. The vibration disturbs the particles in the surrounding medium; those particles disturb those next to them, and so on. The pattern of the disturbance creates outward movement in a wave pattern, like waves of seawater on the ocean. The wave carries the sound energy through the medium, usually in all directions and less intensely as it moves farther from the source.

An audio frequency (abbreviation: AF) or audible frequency is characterized as a periodic vibration whose frequency is audible to the average human. The SI unit of audio frequency is the hertz (Hz). It is the property of sound that most determines pitch.[1]

The generally accepted standard range of audible frequencies is 20 to 20,000 Hz,[2][3][4] although the range of frequencies individuals hear is greatly influenced by environmental factors. Frequencies below 20 Hz are generally felt rather than heard, assuming the amplitude of the vibration is great enough. Frequencies above 20,000 Hz can sometimes be sensed by young people. High frequencies are the first to be affected by hearing loss due to age and/or prolonged exposure to very loud noises.[5]

The hertz (symbol Hz) is the unit of frequency in the International System of Units (SI) and is defined as one cycle per second.[1] It is named for Heinrich Rudolf Hertz, the first person to provide conclusive proof of the existence of electromagnetic waves.

One of the unit's most common uses is in the description of sine waves and musical tones, particularly those used in radio and other audio-related applications. It is also used to describe the speeds at which computers and other electronics are driven

In music, the term note has two primary meanings:
1.A sign used in musical notation to represent the relative duration and pitch of a sound (♪, ♫);
2.A pitched sound itself.

Notes are the "atoms" of much written music: discretizations of musical phenomena that facilitate performance, comprehension, and analysis.[1]

The term note can be used in both generic and specific senses: one might say either "the piece 'Happy Birthday to You' begins with two notes having the same pitch," or "the piece begins with two repetitions of the same note." In the former case, one uses note to refer to a specific musical event; in the latter, one uses the term to refer to a class of events sharing the same pitch. (See also: Key signature names and translations).

Two notes with fundamental frequencies in a ratio equal to any power of two (e.g., half, twice, or four times) are perceived as very similar. Because of that, all notes with these kinds of relations can be grouped under the same pitch class.

In traditional music theory, most countries in the world use the naming convention Do-Re-Mi-Fa-Sol-La-Si, including for instance Italy, Spain, France, Romania, most Latin American countries, Greece, Bulgaria, Turkey, Russia, and all the Arabic-speaking or Persian-speaking countries. However, within the English-speaking and Dutch-speaking world, pitch classes are typically represented by the first seven letters of the Latin alphabet (A, B, C, D, E, F and G). A few European countries, including Germany, adopt an almost identical notation, in which H substitutes for B (see below for details).

The eighth note, or octave, is given the same name as the first, but has double its frequency. The name octave is also used to indicate the span between a note and another with double frequency. To differentiate two notes that have the same pitch class but fall into different octaves, the system of scientific pitch notation combines a letter name with an Arabic numeral designating a specific octave. For example, the now-standard tuning pitch for most Western music, 440 Hz, is named a′ or A4.

There are two formal systems to define each note and octave, the Helmholtz pitch notation and the Scientific pitch notation

In music, timbre (/ˈtæmbər/ TAM-bər or /ˈtɪmbər/ TIM-bər) also known as tone color or tone quality from psychoacoustics, is the quality of a musical note, sound, or tone that distinguishes different types of sound production, such as voices and musical instruments, string instruments, wind instruments, and percussion instruments. The physical characteristics of sound that determine the perception of timbre include spectrum and envelope.

In simple terms, timbre is what makes a particular musical sound different from another, even when they have the same pitch and loudness. For instance, it is the difference between a guitar and a piano playing the same note at the same loudness. Experienced musicians are able to distinguish between different instruments of the same type based on their varied timbres, even if those instruments are playing notes at the same pitch and loudness.

An overtone is any frequency higher than the fundamental frequency of a sound. Using the model of Fourier analysis, the fundamental and the overtones together are called partials. Harmonics, or more precisely, harmonic partials, are partials whose frequencies are integer multiples of the fundamental (including the fundamental which is 1 times itself). These overlapping terms are variously used when discussing the acoustic behavior of musical instruments.[1] (See etymology below.) The model of Fourier analysis provides for the inclusion of inharmonic partials, which are partials whose frequencies are not whole-number ratios of the fundamental (such as 1.1 or 2.14179).

When a resonant system such as a blown pipe or plucked string is excited, a number of overtones may be produced along with the fundamental tone. In simple cases, such as for most musical instruments, the frequencies of these tones are the same as (or close to) the harmonics. Examples of exceptions include the circular drum, – a timpani whose first overtone is about 1.6 times its fundamental resonance frequency,[2] gongs and cymbals, and brass instruments. The human vocal tract is able to produce highly variable amplitudes of the overtones, called formants, which define different vowels




So now that I have loaded this post with Wiki definitions we can discuss how it applies to audio systems. It is not necessary to understand the theories to glean a basic understanding of how a speaker system works to reproduce music. The most common component used to reproduce sound is an electromechanical speaker, there are others such as piezoelectric and hydraulic wave generators, but the basic design is basically an electromagnetic motor attached to a piston which moves up and down in a 1:1 ratio of cone movement to frequency. Essentially a speaker must move up and down 30 times a second to produce a 30 hz sound wave or note. Bear in mind that music is a complex arrangement of notes and harmonies of infinitely varying pitch and timbre, not individual isolated frequencies, so the speaker will need to transition to different notes and frequencies of infinite variations and arrangements. This being said a speakers frequency respose is determined by its cone mass and density, suspension compliance or stiffness, and motor capabilities. in layman terms a larger heavier speaker will be better suited for low frequencies vs a lighter smaller speaker, the larger speaker can reproduce higher frequencies but will not do so efficiently or at volume and vice versa with small speakers.

We know about frequency but what is volume? volume is the amplitude or the distance the speaker cone travels. so in order to increase the volume of a 30hz note the speaker must still cycle 30 times a second, but now must travel further linearly while maintaining its frequency. this in effect is why we use large high excursion (long travel) subwoofers to reproduce sub-bass at high volume and small nimble lightweight speakers for mids and tiny high speed speakers for highs. This where the power myth gets dispelled. If we use crossovers (frequency separation) we can isolate the frequencies and divide the spectrum up and let appropriate size speakers reproduce the right frequencies. This is essential for sound quality and power handling. Lets look at a generic 4 inch midrange with a response of 200 to 2khz. If we try and make the speaker reproduce frequencies below 200 it will be capable at low power.but essentially be limited by its x-max(linear excursion limits). as we start increasing volume(amplitude) the cone will quickly reach its limit and either cause the cone shape to distort and or cause mechanical damage. In this situation we have restricted the power handling of the speaker due to mechanical constraints vs thermal constraints. If we are within the thermal capabilities of the speakers power handling we can apply a crossover to block frequencies below the speakers working threshold and safely amp up the speaker as the frequencies above the speakers threshold will not max out the mechanical limits. bear in mind that crossovers don't completely block frequencies but rather roll off at a ratio of decibels to octave. eg. a 6db sloped crossover will filter frequencies starting with the cutoff frequency and dropping off at a rate 6 decibel per octave. In essence if our 4 inch speaker can handle 120 watts(this rating is a thermal rating based on the speakers working frequency range) we will be overpowering it with a 120watt 30 hz note but be fine with a 120watt 400hz note. If we utilize crossovers and proper level matching all speakers will peak at same volume and essentially be power balanced.

. My rationale is that in a 4 channel sub-less system, the rear speakers are usually necessary to fill in the low bass, because they're usually larger than the fronts, and even if they're not, without a sub, you need all the help you can get with bass. Once you've got the bass handled by a sub, your rear speakers don't do much other than provide a little rear fill. If you run them as loud as the front speakers, you lose the proper stereo image. Because of this, I devote my power to my fronts and my sub, and if I run rears at all, it's just off head unit power.

This set up will work but your rational that you will not need the rears once the subs are installed is wrong, you will need them more than every to achieve true sound quality. consider plucking a guitar string. in order to accurately reproduce the sound the pick makes as it strikes the string or the rise and fall of its amplitude, you will need to use multiple drivers of varying sizes to accurately reproduce pitch and timbre. another example is the drumstick striking the membrane (there is a click in unison with the thud). Unless you are playing pure notes you will need midbass speakers to reproduce the overtones that go with the bass notes and bass speakers to go with the sub-bass notes and so on. This was Infinity's justification for offering a ceramic ribbon tweeter capable of frequencies up to 45khz, which is 25khz above what can be heard by the average human. Its sole purpose is to provide overtones inaudible to the human ear but which affect the frequencies we hear. It takes the whole system to accurately reproduce bass harmonies most think is solely produced by subwoofers. Sound stage image is a different realm and encompasses the perception where we think the sound is coming from. Ideally a system with proper image will give the impression of sitting in a concert hall and the different instruments will sound as if they are coming from their respective locations of the real thing. This is not determined by volume but more by frequency content and distance from listener. The higher the frequency the more directional it is. eg: sub frequencies are hard to judge the source and sound like they come from all around vs high frequencies which are more focused. a simple trick to help move the soundstage foreward is to mount tweeters in top of door like a sailpanel or in the dash.

I hope this is not to confusing or off tangent but I think it helps give a better understanding of the extreme complexity of accurate sound reproduction in an automobile and dispel some of the misconceptions of speaker system construction. You have to consider all variables and remember that its a system working in unison not individual components operating solo.

I will go into signal, power, and amp systems in my next posts. I will try to keep the successive posts more streamlined and less bloated to make reading easier.

[RC10th]

I made up a board to mount the amps which came out pretty good. I'll get my sub monday so all that's left is cabin speakers.

[Jim85IROC]

Sorry for the novel, you can skip the green as they are basically Wiki definitions if you want, but I wanted to have a basis for what music is.

A sound wave is the pattern of disturbance caused by the movement of energy traveling through a medium (such as air, water, or any other liquid or solid matter) as it propagates away from the source of the sound. The source is some object that causes a vibration, such as a ringing telephone, or a person's vocal chords. The vibration disturbs the particles in the surrounding medium; those particles disturb those next to them, and so on. The pattern of the disturbance creates outward movement in a wave pattern, like waves of seawater on the ocean. The wave carries the sound energy through the medium, usually in all directions and less intensely as it moves farther from the source.

An audio frequency (abbreviation: AF) or audible frequency is characterized as a periodic vibration whose frequency is audible to the average human. The SI unit of audio frequency is the hertz (Hz). It is the property of sound that most determines pitch.[1]

The generally accepted standard range of audible frequencies is 20 to 20,000 Hz,[2][3][4] although the range of frequencies individuals hear is greatly influenced by environmental factors. Frequencies below 20 Hz are generally felt rather than heard, assuming the amplitude of the vibration is great enough. Frequencies above 20,000 Hz can sometimes be sensed by young people. High frequencies are the first to be affected by hearing loss due to age and/or prolonged exposure to very loud noises.[5]

The hertz (symbol Hz) is the unit of frequency in the International System of Units (SI) and is defined as one cycle per second.[1] It is named for Heinrich Rudolf Hertz, the first person to provide conclusive proof of the existence of electromagnetic waves.

One of the unit's most common uses is in the description of sine waves and musical tones, particularly those used in radio and other audio-related applications. It is also used to describe the speeds at which computers and other electronics are driven

In music, the term note has two primary meanings:
1.A sign used in musical notation to represent the relative duration and pitch of a sound (♪, ♫);
2.A pitched sound itself.

Notes are the "atoms" of much written music: discretizations of musical phenomena that facilitate performance, comprehension, and analysis.[1]

The term note can be used in both generic and specific senses: one might say either "the piece 'Happy Birthday to You' begins with two notes having the same pitch," or "the piece begins with two repetitions of the same note." In the former case, one uses note to refer to a specific musical event; in the latter, one uses the term to refer to a class of events sharing the same pitch. (See also: Key signature names and translations).

Two notes with fundamental frequencies in a ratio equal to any power of two (e.g., half, twice, or four times) are perceived as very similar. Because of that, all notes with these kinds of relations can be grouped under the same pitch class.

In traditional music theory, most countries in the world use the naming convention Do-Re-Mi-Fa-Sol-La-Si, including for instance Italy, Spain, France, Romania, most Latin American countries, Greece, Bulgaria, Turkey, Russia, and all the Arabic-speaking or Persian-speaking countries. However, within the English-speaking and Dutch-speaking world, pitch classes are typically represented by the first seven letters of the Latin alphabet (A, B, C, D, E, F and G). A few European countries, including Germany, adopt an almost identical notation, in which H substitutes for B (see below for details).

The eighth note, or octave, is given the same name as the first, but has double its frequency. The name octave is also used to indicate the span between a note and another with double frequency. To differentiate two notes that have the same pitch class but fall into different octaves, the system of scientific pitch notation combines a letter name with an Arabic numeral designating a specific octave. For example, the now-standard tuning pitch for most Western music, 440 Hz, is named a′ or A4.

There are two formal systems to define each note and octave, the Helmholtz pitch notation and the Scientific pitch notation

In music, timbre (/ˈtæmbər/ TAM-bər or /ˈtɪmbər/ TIM-bər) also known as tone color or tone quality from psychoacoustics, is the quality of a musical note, sound, or tone that distinguishes different types of sound production, such as voices and musical instruments, string instruments, wind instruments, and percussion instruments. The physical characteristics of sound that determine the perception of timbre include spectrum and envelope.

In simple terms, timbre is what makes a particular musical sound different from another, even when they have the same pitch and loudness. For instance, it is the difference between a guitar and a piano playing the same note at the same loudness. Experienced musicians are able to distinguish between different instruments of the same type based on their varied timbres, even if those instruments are playing notes at the same pitch and loudness.

An overtone is any frequency higher than the fundamental frequency of a sound. Using the model of Fourier analysis, the fundamental and the overtones together are called partials. Harmonics, or more precisely, harmonic partials, are partials whose frequencies are integer multiples of the fundamental (including the fundamental which is 1 times itself). These overlapping terms are variously used when discussing the acoustic behavior of musical instruments.[1] (See etymology below.) The model of Fourier analysis provides for the inclusion of inharmonic partials, which are partials whose frequencies are not whole-number ratios of the fundamental (such as 1.1 or 2.14179).

When a resonant system such as a blown pipe or plucked string is excited, a number of overtones may be produced along with the fundamental tone. In simple cases, such as for most musical instruments, the frequencies of these tones are the same as (or close to) the harmonics. Examples of exceptions include the circular drum, – a timpani whose first overtone is about 1.6 times its fundamental resonance frequency,[2] gongs and cymbals, and brass instruments. The human vocal tract is able to produce highly variable amplitudes of the overtones, called formants, which define different vowels




So now that I have loaded this post with Wiki definitions we can discuss how it applies to audio systems. It is not necessary to understand the theories to glean a basic understanding of how a speaker system works to reproduce music. The most common component used to reproduce sound is an electromechanical speaker, there are others such as piezoelectric and hydraulic wave generators, but the basic design is basically an electromagnetic motor attached to a piston which moves up and down in a 1:1 ratio of cone movement to frequency. Essentially a speaker must move up and down 30 times a second to produce a 30 hz sound wave or note. Bear in mind that music is a complex arrangement of notes and harmonies of infinitely varying pitch and timbre, not individual isolated frequencies, so the speaker will need to transition to different notes and frequencies of infinite variations and arrangements. This being said a speakers frequency respose is determined by its cone mass and density, suspension compliance or stiffness, and motor capabilities. in layman terms a larger heavier speaker will be better suited for low frequencies vs a lighter smaller speaker, the larger speaker can reproduce higher frequencies but will not do so efficiently or at volume and vice versa with small speakers.

We know about frequency but what is volume? volume is the amplitude or the distance the speaker cone travels. so in order to increase the volume of a 30hz note the speaker must still cycle 30 times a second, but now must travel further linearly while maintaining its frequency. this in effect is why we use large high excursion (long travel) subwoofers to reproduce sub-bass at high volume and small nimble lightweight speakers for mids and tiny high speed speakers for highs. This where the power myth gets dispelled. If we use crossovers (frequency separation) we can isolate the frequencies and divide the spectrum up and let appropriate size speakers reproduce the right frequencies. This is essential for sound quality and power handling. Lets look at a generic 4 inch midrange with a response of 200 to 2khz. If we try and make the speaker reproduce frequencies below 200 it will be capable at low power.but essentially be limited by its x-max(linear excursion limits). as we start increasing volume(amplitude) the cone will quickly reach its limit and either cause the cone shape to distort and or cause mechanical damage. In this situation we have restricted the power handling of the speaker due to mechanical constraints vs thermal constraints. If we are within the thermal capabilities of the speakers power handling we can apply a crossover to block frequencies below the speakers working threshold and safely amp up the speaker as the frequencies above the speakers threshold will not max out the mechanical limits. bear in mind that crossovers don't completely block frequencies but rather roll off at a ratio of decibels to octave. eg. a 6db sloped crossover will filter frequencies starting with the cutoff frequency and dropping off at a rate 6 decibel per octave. In essence if our 4 inch speaker can handle 120 watts(this rating is a thermal rating based on the speakers working frequency range) we will be overpowering it with a 120watt 30 hz note but be fine with a 120watt 400hz note. If we utilize crossovers and proper level matching all speakers will peak at same volume and essentially be power balanced.

. My rationale is that in a 4 channel sub-less system, the rear speakers are usually necessary to fill in the low bass, because they're usually larger than the fronts, and even if they're not, without a sub, you need all the help you can get with bass. Once you've got the bass handled by a sub, your rear speakers don't do much other than provide a little rear fill. If you run them as loud as the front speakers, you lose the proper stereo image. Because of this, I devote my power to my fronts and my sub, and if I run rears at all, it's just off head unit power.

This set up will work but your rational that you will not need the rears once the subs are installed is wrong, you will need them more than every to achieve true sound quality. consider plucking a guitar string. in order to accurately reproduce the sound the pick makes as it strikes the string or the rise and fall of its amplitude, you will need to use multiple drivers of varying sizes to accurately reproduce pitch and timbre. another example is the drumstick striking the membrane (there is a click in unison with the thud). Unless you are playing pure notes you will need midbass speakers to reproduce the overtones that go with the bass notes and bass speakers to go with the sub-bass notes and so on. This was Infinity's justification for offering a ceramic ribbon tweeter capable of frequencies up to 45khz, which is 25khz above what can be heard by the average human. Its sole purpose is to provide overtones inaudible to the human ear but which affect the frequencies we hear. It takes the whole system to accurately reproduce bass harmonies most think is solely produced by subwoofers. Sound stage image is a different realm and encompasses the perception where we think the sound is coming from. Ideally a system with proper image will give the impression of sitting in a concert hall and the different instruments will sound as if they are coming from their respective locations of the real thing. This is not determined by volume but more by frequency content and distance from listener. The higher the frequency the more directional it is. eg: sub frequencies are hard to judge the source and sound like they come from all around vs high frequencies which are more focused. a simple trick to help move the soundstage foreward is to mount tweeters in top of door like a sailpanel or in the dash.

I hope this is not to confusing or off tangent but I think it helps give a better understanding of the extreme complexity of accurate sound reproduction in an automobile and dispel some of the misconceptions of speaker system construction. You have to consider all variables and remember that its a system working in unison not individual components operating solo.

I will go into signal, power, and amp systems in my next posts. I will try to keep the successive posts more streamlined and less bloated to make reading easier.

Sorry, but I don't agree that rear speakers are necessary. I'm well aware of the need for full spectrum coverage, but a car environment is full of comprimises, and I prefer to keep as much of my sound in front of me as possible. If I had room, I'd put my subs up front too. I have done installations where I run midbass drivers in the rear when I can't get adequate midbass up front, but I prefer not to.

In a basic 4 channel system with full range rear speakers, all the midrange and high frequency content ruins the stereo image. If you like the "all around" sound that's fine, but I strive for an accurate soundstage that's as far in front as I can get it.

[Jim85IROC]

Sorry for the novel, you can skip the green as they are basically Wiki definitions if you want, but I wanted to have a basis for what music is.

A sound wave is the pattern of disturbance caused by the movement of energy traveling through a medium (such as air, water, or any other liquid or solid matter) as it propagates away from the source of the sound. The source is some object that causes a vibration, such as a ringing telephone, or a person's vocal chords. The vibration disturbs the particles in the surrounding medium; those particles disturb those next to them, and so on. The pattern of the disturbance creates outward movement in a wave pattern, like waves of seawater on the ocean. The wave carries the sound energy through the medium, usually in all directions and less intensely as it moves farther from the source.

An audio frequency (abbreviation: AF) or audible frequency is characterized as a periodic vibration whose frequency is audible to the average human. The SI unit of audio frequency is the hertz (Hz). It is the property of sound that most determines pitch.[1]

The generally accepted standard range of audible frequencies is 20 to 20,000 Hz,[2][3][4] although the range of frequencies individuals hear is greatly influenced by environmental factors. Frequencies below 20 Hz are generally felt rather than heard, assuming the amplitude of the vibration is great enough. Frequencies above 20,000 Hz can sometimes be sensed by young people. High frequencies are the first to be affected by hearing loss due to age and/or prolonged exposure to very loud noises.[5]

The hertz (symbol Hz) is the unit of frequency in the International System of Units (SI) and is defined as one cycle per second.[1] It is named for Heinrich Rudolf Hertz, the first person to provide conclusive proof of the existence of electromagnetic waves.

One of the unit's most common uses is in the description of sine waves and musical tones, particularly those used in radio and other audio-related applications. It is also used to describe the speeds at which computers and other electronics are driven

In music, the term note has two primary meanings:
1.A sign used in musical notation to represent the relative duration and pitch of a sound (♪, ♫);
2.A pitched sound itself.

Notes are the "atoms" of much written music: discretizations of musical phenomena that facilitate performance, comprehension, and analysis.[1]

The term note can be used in both generic and specific senses: one might say either "the piece 'Happy Birthday to You' begins with two notes having the same pitch," or "the piece begins with two repetitions of the same note." In the former case, one uses note to refer to a specific musical event; in the latter, one uses the term to refer to a class of events sharing the same pitch. (See also: Key signature names and translations).

Two notes with fundamental frequencies in a ratio equal to any power of two (e.g., half, twice, or four times) are perceived as very similar. Because of that, all notes with these kinds of relations can be grouped under the same pitch class.

In traditional music theory, most countries in the world use the naming convention Do-Re-Mi-Fa-Sol-La-Si, including for instance Italy, Spain, France, Romania, most Latin American countries, Greece, Bulgaria, Turkey, Russia, and all the Arabic-speaking or Persian-speaking countries. However, within the English-speaking and Dutch-speaking world, pitch classes are typically represented by the first seven letters of the Latin alphabet (A, B, C, D, E, F and G). A few European countries, including Germany, adopt an almost identical notation, in which H substitutes for B (see below for details).

The eighth note, or octave, is given the same name as the first, but has double its frequency. The name octave is also used to indicate the span between a note and another with double frequency. To differentiate two notes that have the same pitch class but fall into different octaves, the system of scientific pitch notation combines a letter name with an Arabic numeral designating a specific octave. For example, the now-standard tuning pitch for most Western music, 440 Hz, is named a′ or A4.

There are two formal systems to define each note and octave, the Helmholtz pitch notation and the Scientific pitch notation

In music, timbre (/ˈtæmbər/ TAM-bər or /ˈtɪmbər/ TIM-bər) also known as tone color or tone quality from psychoacoustics, is the quality of a musical note, sound, or tone that distinguishes different types of sound production, such as voices and musical instruments, string instruments, wind instruments, and percussion instruments. The physical characteristics of sound that determine the perception of timbre include spectrum and envelope.

In simple terms, timbre is what makes a particular musical sound different from another, even when they have the same pitch and loudness. For instance, it is the difference between a guitar and a piano playing the same note at the same loudness. Experienced musicians are able to distinguish between different instruments of the same type based on their varied timbres, even if those instruments are playing notes at the same pitch and loudness.

An overtone is any frequency higher than the fundamental frequency of a sound. Using the model of Fourier analysis, the fundamental and the overtones together are called partials. Harmonics, or more precisely, harmonic partials, are partials whose frequencies are integer multiples of the fundamental (including the fundamental which is 1 times itself). These overlapping terms are variously used when discussing the acoustic behavior of musical instruments.[1] (See etymology below.) The model of Fourier analysis provides for the inclusion of inharmonic partials, which are partials whose frequencies are not whole-number ratios of the fundamental (such as 1.1 or 2.14179).

When a resonant system such as a blown pipe or plucked string is excited, a number of overtones may be produced along with the fundamental tone. In simple cases, such as for most musical instruments, the frequencies of these tones are the same as (or close to) the harmonics. Examples of exceptions include the circular drum, – a timpani whose first overtone is about 1.6 times its fundamental resonance frequency,[2] gongs and cymbals, and brass instruments. The human vocal tract is able to produce highly variable amplitudes of the overtones, called formants, which define different vowels




So now that I have loaded this post with Wiki definitions we can discuss how it applies to audio systems. It is not necessary to understand the theories to glean a basic understanding of how a speaker system works to reproduce music. The most common component used to reproduce sound is an electromechanical speaker, there are others such as piezoelectric and hydraulic wave generators, but the basic design is basically an electromagnetic motor attached to a piston which moves up and down in a 1:1 ratio of cone movement to frequency. Essentially a speaker must move up and down 30 times a second to produce a 30 hz sound wave or note. Bear in mind that music is a complex arrangement of notes and harmonies of infinitely varying pitch and timbre, not individual isolated frequencies, so the speaker will need to transition to different notes and frequencies of infinite variations and arrangements. This being said a speakers frequency respose is determined by its cone mass and density, suspension compliance or stiffness, and motor capabilities. in layman terms a larger heavier speaker will be better suited for low frequencies vs a lighter smaller speaker, the larger speaker can reproduce higher frequencies but will not do so efficiently or at volume and vice versa with small speakers.

We know about frequency but what is volume? volume is the amplitude or the distance the speaker cone travels. so in order to increase the volume of a 30hz note the speaker must still cycle 30 times a second, but now must travel further linearly while maintaining its frequency. this in effect is why we use large high excursion (long travel) subwoofers to reproduce sub-bass at high volume and small nimble lightweight speakers for mids and tiny high speed speakers for highs. This where the power myth gets dispelled. If we use crossovers (frequency separation) we can isolate the frequencies and divide the spectrum up and let appropriate size speakers reproduce the right frequencies. This is essential for sound quality and power handling. Lets look at a generic 4 inch midrange with a response of 200 to 2khz. If we try and make the speaker reproduce frequencies below 200 it will be capable at low power.but essentially be limited by its x-max(linear excursion limits). as we start increasing volume(amplitude) the cone will quickly reach its limit and either cause the cone shape to distort and or cause mechanical damage. In this situation we have restricted the power handling of the speaker due to mechanical constraints vs thermal constraints. If we are within the thermal capabilities of the speakers power handling we can apply a crossover to block frequencies below the speakers working threshold and safely amp up the speaker as the frequencies above the speakers threshold will not max out the mechanical limits. bear in mind that crossovers don't completely block frequencies but rather roll off at a ratio of decibels to octave. eg. a 6db sloped crossover will filter frequencies starting with the cutoff frequency and dropping off at a rate 6 decibel per octave. In essence if our 4 inch speaker can handle 120 watts(this rating is a thermal rating based on the speakers working frequency range) we will be overpowering it with a 120watt 30 hz note but be fine with a 120watt 400hz note. If we utilize crossovers and proper level matching all speakers will peak at same volume and essentially be power balanced.

. My rationale is that in a 4 channel sub-less system, the rear speakers are usually necessary to fill in the low bass, because they're usually larger than the fronts, and even if they're not, without a sub, you need all the help you can get with bass. Once you've got the bass handled by a sub, your rear speakers don't do much other than provide a little rear fill. If you run them as loud as the front speakers, you lose the proper stereo image. Because of this, I devote my power to my fronts and my sub, and if I run rears at all, it's just off head unit power.

This set up will work but your rational that you will not need the rears once the subs are installed is wrong, you will need them more than every to achieve true sound quality. consider plucking a guitar string. in order to accurately reproduce the sound the pick makes as it strikes the string or the rise and fall of its amplitude, you will need to use multiple drivers of varying sizes to accurately reproduce pitch and timbre. another example is the drumstick striking the membrane (there is a click in unison with the thud). Unless you are playing pure notes you will need midbass speakers to reproduce the overtones that go with the bass notes and bass speakers to go with the sub-bass notes and so on. This was Infinity's justification for offering a ceramic ribbon tweeter capable of frequencies up to 45khz, which is 25khz above what can be heard by the average human. Its sole purpose is to provide overtones inaudible to the human ear but which affect the frequencies we hear. It takes the whole system to accurately reproduce bass harmonies most think is solely produced by subwoofers. Sound stage image is a different realm and encompasses the perception where we think the sound is coming from. Ideally a system with proper image will give the impression of sitting in a concert hall and the different instruments will sound as if they are coming from their respective locations of the real thing. This is not determined by volume but more by frequency content and distance from listener. The higher the frequency the more directional it is. eg: sub frequencies are hard to judge the source and sound like they come from all around vs high frequencies which are more focused. a simple trick to help move the soundstage foreward is to mount tweeters in top of door like a sailpanel or in the dash.

I hope this is not to confusing or off tangent but I think it helps give a better understanding of the extreme complexity of accurate sound reproduction in an automobile and dispel some of the misconceptions of speaker system construction. You have to consider all variables and remember that its a system working in unison not individual components operating solo.

I will go into signal, power, and amp systems in my next posts. I will try to keep the successive posts more streamlined and less bloated to make reading easier.

Sorry, but I don't agree that rear speakers are necessary. I'm well aware of the need for full spectrum coverage, but a car environment is full of comprimises, and I prefer to keep as much of my sound in front of me as possible. If I had room, I'd put my subs up front too. I have done installations where I run midbass drivers in the rear when I can't get adequate midbass up front, but I prefer not to.

In a basic 4 channel system with full range rear speakers, all the midrange and high frequency content ruins the stereo image. If you like the "all around" sound that's fine, but I strive for an accurate soundstage that's as far in front as I can get it.

[RC10th]

Well, today I ran all of the cables neatly under the sill panels in a cavity. Unfortunately the RCA cables and speaker wire were too short, so I'll probably have to make my own RCA's and splitter extensions to get the right lengths. I'll also have to buy more speaker wire I was hoping to put the back seat and carpet in but that will have to wait.

Wrestling and feeding the 4 gauge power wire under the dash was a bit of a challenge, it's some pretty thick cable. I like the fact the wires are hidden as it looks pretty factory.

[V12]

Sorry, but I don't agree that rear speakers are necessary. I'm well aware of the need for full spectrum coverage, but a car environment is full of comprimises, and I prefer to keep as much of my sound in front of me as possible. If I had room, I'd put my subs up front too. I have done installations where I run midbass drivers in the rear when I can't get adequate midbass up front, but I prefer not to.

In a basic 4 channel system with full range rear speakers, all the midrange and high frequency content ruins the stereo image. If you like the "all around" sound that's fine, but I strive for an accurate soundstage that's as far in front as I can get it.

Fully agree with that. When I built my last car system, I finally just used an expensive front system and a sub. Rear speakers always ruined the sound so I removed them at some point.
I think a really good front system is a must. Also spending money for a few selected speakers/amps is much better than buying lots of cheap stuff.
Long ago since I built that system and I really miss that sound, afterwards went with sound system what came with the car as with modern cars most times it´s too difficult exchanging anything.

BTW for the old car I used Alpine, Soundstream and Phoenix Gold amp. Someone remembers the old Phoenix amps?
Sub was Lanzar, don´t remember the front system.