I see a lot of the same questions raised time and time again, so put this together in the hope that it may help some people out.
Bear in mind it's reasonably generic, and put in as simple language as possible so I have been a little 'loose' in the hope that it may be easier to understand. This is for audio beginners, if you are a pro then you don't need this thread! Any suggestions though, send them through!
Now firstly some important terms:
Power rating: One important thing to know when buying a head unit and speakers... do NOT be fooled, the power rating on a head unit is always rated in PMPO (often around 45W to 52W). This is the amount of power it can produce for a few milliseconds. The real figure you need is its continuous power rating which is its RMS rating. Most head units will produce around 15 to 20Wrms. Some speaker manufacturers will quote the RMS figure, but a lot of the cheaper ones will try to fool you by giving you the PMPO rating.
SQ & SPL: The 2 streams of car audio. SQ stands for Sound Quality. This is when you go all out for audio perfection, using high quality components. You want a crisp and extremely accurate and musical audio reproduction across the whole frequency range. SPL stands for Sound Pressure Level. This basically means... LOUD. These are the systems you can hear booming 3 blocks away with windows expanding and bolts being rattled loose. To be quite frank I don't see the point in this sort of system as you cant hear anything except your ears screaming at you. You make a good SQ system and it will go just as loud but be much nicer to listen to as its not all about doof-doof. It also tends to be more expensive and takes more thought and preparation.
Woofer: These speakers generally range from 5.25" through to 8" diameter. They play the midbass frequencies. Sub woofers range from around 8" though to 15" diameter in most common car applications. Sub woofers are usually crossed over so they play the sub bass frequencies of around 80Hz and below, quite often hitting 30Hz or lower in a tuned ported application.
A sound absorbing tile behind each speaker is also good, so sound waves don't bounce off the outside door panel back onto the rear of the speaker cone causing distortion.
You can make MDF door baffles, but it depends on the car as to whether this is needed. The factory ones generally have a good angle on them which is hard to replicate. In the Magna the plastic mount was VERY solid and there was no need. I haven't had the trim off the Legnum yet so not sure what it is like.
Amplifier:
This is a very important component of the system. There is a little one inside the actual head unit itself, but as a whole they are pretty useless. An amplifier takes the audio signal from the head unit and makes it bigger... amplifiers it. The most common amplifiers are 2 Channel, 4 Channel and Monoblocks.
2 Channel amps are used for power 2 speakers, 1 off each channel.
4 Channel amps can be used in 2 ways... one is to power 4 sets of speakers, or the other is to power 2 speakers of 2 channels and bridge (join) the remaining 2 channels together to power a small subwoofer. I personally am not a fan of bridging but if on a budget it is convenient!
A Monoblock amp is a single channel amp, generally high powered and efficient designed for powering subwoofers.
Recommendations: Focal, Alpine, Audison, Vibe etc
Non-Recommendations: Sony, Kenwood, Clarion, Fusion
Capacitors:A complete and utter waste of time. For posers only. They are a bandaid fix for not paying the bit extra to get a thicker power cable from the battery to the amp or upgrading your battery. I have a Optima yellow top, 2 gauge cable and 1300W of amps and not a single flicker in my lights. They are also a fire hazard and dangerous if connected incorrectly.
Take your time, enjoy it and learn. Do it right the first time and you will not regret it. Buy cheap or cut corners and you will curse yourself later. Feel free to contact me with any questions or comments!
Bear in mind it's reasonably generic, and put in as simple language as possible so I have been a little 'loose' in the hope that it may be easier to understand. This is for audio beginners, if you are a pro then you don't need this thread! Any suggestions though, send them through!
Car audio is probably one of the most challenging audio experiences around. You are trying to reproduce quality sound in a tin can full of holes and vibrating sheet metal and plastic. Its a learning curve that gets more and more involved (and expensive!) the further you go in search of perfection.
NOTE: I am a firm believer of do it right the 1st time!! If you don't have the money, do without it and save till you do. You will curse yourself otherwise!
First of all... sit back and close your eyes, imagine you are at a live concert. The band/musicians are directly in front of you and about head height. OK, now we have to reproduce that in a car from the recording! Problem... You are not in the centre of the car, the speaker boxes are tin can doors full of holes and everyone is sitting in different positions... not good. Hopefully the thesis below will help you get somewhere towards this goal! NOTE: I am a firm believer of do it right the 1st time!! If you don't have the money, do without it and save till you do. You will curse yourself otherwise!
Now firstly some important terms:
Power rating: One important thing to know when buying a head unit and speakers... do NOT be fooled, the power rating on a head unit is always rated in PMPO (often around 45W to 52W). This is the amount of power it can produce for a few milliseconds. The real figure you need is its continuous power rating which is its RMS rating. Most head units will produce around 15 to 20Wrms. Some speaker manufacturers will quote the RMS figure, but a lot of the cheaper ones will try to fool you by giving you the PMPO rating.
SQ & SPL: The 2 streams of car audio. SQ stands for Sound Quality. This is when you go all out for audio perfection, using high quality components. You want a crisp and extremely accurate and musical audio reproduction across the whole frequency range. SPL stands for Sound Pressure Level. This basically means... LOUD. These are the systems you can hear booming 3 blocks away with windows expanding and bolts being rattled loose. To be quite frank I don't see the point in this sort of system as you cant hear anything except your ears screaming at you. You make a good SQ system and it will go just as loud but be much nicer to listen to as its not all about doof-doof. It also tends to be more expensive and takes more thought and preparation.
Woofer: These speakers generally range from 5.25" through to 8" diameter. They play the midbass frequencies. Sub woofers range from around 8" though to 15" diameter in most common car applications. Sub woofers are usually crossed over so they play the sub bass frequencies of around 80Hz and below, quite often hitting 30Hz or lower in a tuned ported application.
Tweeter: These are the smaller speakers that focus on the higher frequencies e.g. female vocals. They range from under 1" to about 2" in diameter. These frequencies are very directional so placement is critical.
Crossover: This is device which takes all the frequencies that your source outputs, separates them and passes them onto the relevant speaker. For example if you buy a pair of splits, the included crossover will pass high frequencies to the tweeter and mid frequencies to the woofer. This ensures that the speakers aren't trying to reproduce frequencies that they aren't designed for. I am not a fan of mounting crossovers on the doors due to the higher chance of moisture and vibration with closing doors etc. I mount mine high up under the dash above the drivers and passangers feet away from where you can kick them, this does mean you need to run an extra set of cables to into the door though for the tweeter.
Speakers: There are a variety of different speakers available on the market, some good and some bad.
Coaxial - This is where the tweeter is hard mounted in the middle of the woofer, often on a pivot joint so the tweeter can be pointed in different directions. Good general speaker, but limited as you are limited in tweeter positioning, and the crossover generally isn't as good a quality as found in a pair of splits.
Splits - Here the tweeter and woofer are separate, so both can be mounted individually to achieve the optimum stage height and imaging. This can introduce new problems though like separation when tweeter and woofer are mounted too far apart, with frequencies from one reaching your ear before the other.
Oval speakers - The common 6x9, 7x10 etc. To be honest... garbage. The ONLY time I would recommend these is if you wanted a bit extra bass without getting a sub. Reason... look at the cone... 2 sides are short and 2 sides are long... result, is a distorted waveform. You do not have equal air pressure or force around the whole cone.
Stage height: This is vital in a good SQ system. Your aim is to hear the sound coming from the centre of the car just above the dash. Tweeter positioning plays the most important role here, as it is the high frequencies that are the most directional. This is where a good pair of splits are worth their weight in gold! You can play around with their positions until the optimum is found. 2 of the most common positions are deep in the kick panels pointed at the opposite persons head so they cross over in the middle, or on the dash as far back as possible in the corner of the A-pillar again pointed at the opposite person. Off axis positioning is another ball game but can be quite successful. The factory tweeter pods in our Legnums/Galants is perfect for a stealth install and still sound pretty good. I would only install them elsewhere is you are aiming for the best and/or trying for SQ comps. I think these will hold a 1" tweeter without to many hassles, but any bigger may require some dremel work.
Now onto the system:
Headunit:
The base of the whole system. A good quality head unit to get the audio off of the source (CD, USB etc) with the least possible interference to audio quality is the best place to start. This can be a humble tape deck all the way through to high end CD players, carputers and DVD surround sound systems. This is the most important choice and the building block for a good SQ system. Things like an equalizer, pre-out voltage levels, timing compensation will all become very helpful when tuning the completed system
This is where you need to have your system design sorted. Do you want fronts, rears, a sub, external amplifier etc?
I would recommend a headunit with 3 pre-outs (RCA) for front, rear and sub. This way you can upgrade later if you want.
A equaliser of some sort is good as well so you can fine tune the system later as there will be peaks/troughs in certain frequencies due to the shape of the car, listening positions etc.
Recommendations: JVC is hard to beat for value for money. Apline and Eclipse also do very good units. The high end Pioneer aren't bad but not a fan of there cheaper models.
Non-Recommendations: Clarion, Sony, Kenwood etc. They get a lot of bad rap and there are better for similar prices.
Speakers:
Aside from the headunit, this is arguably the most important part of the system. The difference between low to mid level speakers is much more important that low to mid level amplifiers.
FRONTS: The next step is speakers. You (the driver) are up front, so that's where most of the money should be spent. Also, that's where music comes from at a concert right! So quite often rear speakers are ignored or cheapish ones put in for the occasional passengers.
Splits running from an amp are the best bet up front as you have the most flexibility.
Coaxials if you want an easier and cheaper install that still sounds nice. Our cars come with splits at the front from factory so I would not recommend getting coaxials as everything is already there for mounting a set of splits and they will sound better!
Recommendations: Morel (I have them and love them), Boston (very musical and smooth), Oz Audio, Hertz (great bass, very American sounding), Apline, Focal (tweeters can be a little bright for my liking) MB Quarts, Crescendo Opus etc, do you your research and try to listen to some! The Reponse Precision range from Jaycar are very good value for money as well. Their ribbon tweeters sound quite good.
Non-Recommendations: JVC, Clarion, Fusion, Kenwood, Pinoeer (no I don't like them, build quality is average, awesome huge stickers for your commodore though)
REARS: Rears (if you want them) are commonly a set of 5.25" to 6.5" coaxials running from the head unit. Used purely as rear fill and to keep the passengers happy. I have mine turned off.
If you have a sedan and are planning to run a sub, I would recommend against rear speakers in the parcel shelf as the sound pressure from the sub will push the speakers causing distortion. A wagon doesn't have this problem.
Recommendations: Same as for the fronts. or you can get some cheap ones to keep the passengers happy.
Non-Recommendations: Same as for the fronts.
SUB: Depending on what you are after drives what sub you get. I personally like a good quality 12" in a sealed box for tight controlled musical bass that can still go low. A 10" would be a tad more musical and even more accurate, but cannot extend as far into the very low frequencies.
Dual subs are for posers or SPL competitions. Spend the money on one better quality sub and you will get much nicer bass.
Ported boxes vs Sealed boxes is a matter of personal preference I have found.
In my opinion I think sealed boxes sound tighter and more musical and are also easier to make. Less boomy and generally smaller.
Porting allows easier frequency tuning and tends to be able to get a lower -3db rollofff, but to me sound a little boomier and require more space.
You can make your own using software like WinISD for calculations or buy a prefab. Depends on how confident you are at woodworking (it needs to be SOLID with no airgaps or flex) and how much time you have.
Recommendations: Morel, Boston, Oz Audio, Alpine, Hertz, DD, and the list goes on!
Non-Recommendations: Sony, Kenwood, Pioneer, Clarion, Fusion etc
Prep Work:
Cable/Fuse: If you are running amplifiers, a fat cable from the battery is a must. Thicker cable means less voltage drop between the battery and the amp. Use a thin cable and the amp is trying to suck huge amounts of current through a tiny straw... try drinking a glass of water using a thick straw and then a thin straw and you will know what I mean.
THIS CABLE MUST BE FUSED!!! General sound off standard is within 45cm of the battery but I would go as close as possible. This is only to protect the main power cable, the amps have their own fuses. This fuse should be a little larger than all the fuses of your amps combined. Make sure that your cable can handle more than the combined max current draw of all your amps as well as you don't want the cable to be a fuse! I would recommend 4AWG (110A rated) as a minimum.
Also if running an amplifier, you will need some RCA cables from the headunit outputs to the amplifier inputs. Run these on the other side of the car to the power cable from the battery. Also try to keep them away from the ECU. These cables will pick up alternator and other electrical noise if not run carefully.
A 4guage cable kit from somewhere like JB is a prety good start if you don't want the hassle of looking at different options. I would recommend buying everything separate though this way you can be a little more picky on the quality of the RCA cables etc.
Door Prep: Door prep is a must if you have invested in some nice splits. This means sealing up all the holes and applying a liberal dose of sound deadening to everything you can. This is a product designed to stick to your panels or trim to add mass to them to lower their resonant frequency so they don't vibrate as much. It is available in 2 common forms. The most common is a bitumen based tar which has one sticky side. It is very dense and heavy and supplied in sheets or rolls about 3mm thick. You peel the protective paper off and stick it on your panels using a roller. Stinger and Dynamat are the best brands. Cheaper stuff will slide off your door on a hot day! The other type is a liquid deadener which you spray or paint on, which sets very hard. This is commonly used for uneven or hard to get places like your door trim.Crossover: This is device which takes all the frequencies that your source outputs, separates them and passes them onto the relevant speaker. For example if you buy a pair of splits, the included crossover will pass high frequencies to the tweeter and mid frequencies to the woofer. This ensures that the speakers aren't trying to reproduce frequencies that they aren't designed for. I am not a fan of mounting crossovers on the doors due to the higher chance of moisture and vibration with closing doors etc. I mount mine high up under the dash above the drivers and passangers feet away from where you can kick them, this does mean you need to run an extra set of cables to into the door though for the tweeter.
Speakers: There are a variety of different speakers available on the market, some good and some bad.
Coaxial - This is where the tweeter is hard mounted in the middle of the woofer, often on a pivot joint so the tweeter can be pointed in different directions. Good general speaker, but limited as you are limited in tweeter positioning, and the crossover generally isn't as good a quality as found in a pair of splits.
Splits - Here the tweeter and woofer are separate, so both can be mounted individually to achieve the optimum stage height and imaging. This can introduce new problems though like separation when tweeter and woofer are mounted too far apart, with frequencies from one reaching your ear before the other.
Oval speakers - The common 6x9, 7x10 etc. To be honest... garbage. The ONLY time I would recommend these is if you wanted a bit extra bass without getting a sub. Reason... look at the cone... 2 sides are short and 2 sides are long... result, is a distorted waveform. You do not have equal air pressure or force around the whole cone.
Stage height: This is vital in a good SQ system. Your aim is to hear the sound coming from the centre of the car just above the dash. Tweeter positioning plays the most important role here, as it is the high frequencies that are the most directional. This is where a good pair of splits are worth their weight in gold! You can play around with their positions until the optimum is found. 2 of the most common positions are deep in the kick panels pointed at the opposite persons head so they cross over in the middle, or on the dash as far back as possible in the corner of the A-pillar again pointed at the opposite person. Off axis positioning is another ball game but can be quite successful. The factory tweeter pods in our Legnums/Galants is perfect for a stealth install and still sound pretty good. I would only install them elsewhere is you are aiming for the best and/or trying for SQ comps. I think these will hold a 1" tweeter without to many hassles, but any bigger may require some dremel work.
Now onto the system:
Headunit:
The base of the whole system. A good quality head unit to get the audio off of the source (CD, USB etc) with the least possible interference to audio quality is the best place to start. This can be a humble tape deck all the way through to high end CD players, carputers and DVD surround sound systems. This is the most important choice and the building block for a good SQ system. Things like an equalizer, pre-out voltage levels, timing compensation will all become very helpful when tuning the completed system
This is where you need to have your system design sorted. Do you want fronts, rears, a sub, external amplifier etc?
I would recommend a headunit with 3 pre-outs (RCA) for front, rear and sub. This way you can upgrade later if you want.
A equaliser of some sort is good as well so you can fine tune the system later as there will be peaks/troughs in certain frequencies due to the shape of the car, listening positions etc.
Recommendations: JVC is hard to beat for value for money. Apline and Eclipse also do very good units. The high end Pioneer aren't bad but not a fan of there cheaper models.
Non-Recommendations: Clarion, Sony, Kenwood etc. They get a lot of bad rap and there are better for similar prices.
Speakers:
Aside from the headunit, this is arguably the most important part of the system. The difference between low to mid level speakers is much more important that low to mid level amplifiers.
FRONTS: The next step is speakers. You (the driver) are up front, so that's where most of the money should be spent. Also, that's where music comes from at a concert right! So quite often rear speakers are ignored or cheapish ones put in for the occasional passengers.
Splits running from an amp are the best bet up front as you have the most flexibility.
Coaxials if you want an easier and cheaper install that still sounds nice. Our cars come with splits at the front from factory so I would not recommend getting coaxials as everything is already there for mounting a set of splits and they will sound better!
Recommendations: Morel (I have them and love them), Boston (very musical and smooth), Oz Audio, Hertz (great bass, very American sounding), Apline, Focal (tweeters can be a little bright for my liking) MB Quarts, Crescendo Opus etc, do you your research and try to listen to some! The Reponse Precision range from Jaycar are very good value for money as well. Their ribbon tweeters sound quite good.
Non-Recommendations: JVC, Clarion, Fusion, Kenwood, Pinoeer (no I don't like them, build quality is average, awesome huge stickers for your commodore though)
REARS: Rears (if you want them) are commonly a set of 5.25" to 6.5" coaxials running from the head unit. Used purely as rear fill and to keep the passengers happy. I have mine turned off.
If you have a sedan and are planning to run a sub, I would recommend against rear speakers in the parcel shelf as the sound pressure from the sub will push the speakers causing distortion. A wagon doesn't have this problem.
Recommendations: Same as for the fronts. or you can get some cheap ones to keep the passengers happy.
Non-Recommendations: Same as for the fronts.
SUB: Depending on what you are after drives what sub you get. I personally like a good quality 12" in a sealed box for tight controlled musical bass that can still go low. A 10" would be a tad more musical and even more accurate, but cannot extend as far into the very low frequencies.
Dual subs are for posers or SPL competitions. Spend the money on one better quality sub and you will get much nicer bass.
Ported boxes vs Sealed boxes is a matter of personal preference I have found.
In my opinion I think sealed boxes sound tighter and more musical and are also easier to make. Less boomy and generally smaller.
Porting allows easier frequency tuning and tends to be able to get a lower -3db rollofff, but to me sound a little boomier and require more space.
You can make your own using software like WinISD for calculations or buy a prefab. Depends on how confident you are at woodworking (it needs to be SOLID with no airgaps or flex) and how much time you have.
Recommendations: Morel, Boston, Oz Audio, Alpine, Hertz, DD, and the list goes on!
Non-Recommendations: Sony, Kenwood, Pioneer, Clarion, Fusion etc
Prep Work:
Cable/Fuse: If you are running amplifiers, a fat cable from the battery is a must. Thicker cable means less voltage drop between the battery and the amp. Use a thin cable and the amp is trying to suck huge amounts of current through a tiny straw... try drinking a glass of water using a thick straw and then a thin straw and you will know what I mean.
THIS CABLE MUST BE FUSED!!! General sound off standard is within 45cm of the battery but I would go as close as possible. This is only to protect the main power cable, the amps have their own fuses. This fuse should be a little larger than all the fuses of your amps combined. Make sure that your cable can handle more than the combined max current draw of all your amps as well as you don't want the cable to be a fuse! I would recommend 4AWG (110A rated) as a minimum.
Also if running an amplifier, you will need some RCA cables from the headunit outputs to the amplifier inputs. Run these on the other side of the car to the power cable from the battery. Also try to keep them away from the ECU. These cables will pick up alternator and other electrical noise if not run carefully.
A 4guage cable kit from somewhere like JB is a prety good start if you don't want the hassle of looking at different options. I would recommend buying everything separate though this way you can be a little more picky on the quality of the RCA cables etc.
A sound absorbing tile behind each speaker is also good, so sound waves don't bounce off the outside door panel back onto the rear of the speaker cone causing distortion.
You can make MDF door baffles, but it depends on the car as to whether this is needed. The factory ones generally have a good angle on them which is hard to replicate. In the Magna the plastic mount was VERY solid and there was no need. I haven't had the trim off the Legnum yet so not sure what it is like.
Amplifier:
This is a very important component of the system. There is a little one inside the actual head unit itself, but as a whole they are pretty useless. An amplifier takes the audio signal from the head unit and makes it bigger... amplifiers it. The most common amplifiers are 2 Channel, 4 Channel and Monoblocks.
2 Channel amps are used for power 2 speakers, 1 off each channel.
4 Channel amps can be used in 2 ways... one is to power 4 sets of speakers, or the other is to power 2 speakers of 2 channels and bridge (join) the remaining 2 channels together to power a small subwoofer. I personally am not a fan of bridging but if on a budget it is convenient!
A Monoblock amp is a single channel amp, generally high powered and efficient designed for powering subwoofers.
Recommendations: Focal, Alpine, Audison, Vibe etc
Non-Recommendations: Sony, Kenwood, Clarion, Fusion
Capacitors:A complete and utter waste of time. For posers only. They are a bandaid fix for not paying the bit extra to get a thicker power cable from the battery to the amp or upgrading your battery. I have a Optima yellow top, 2 gauge cable and 1300W of amps and not a single flicker in my lights. They are also a fire hazard and dangerous if connected incorrectly.
Take your time, enjoy it and learn. Do it right the first time and you will not regret it. Buy cheap or cut corners and you will curse yourself later. Feel free to contact me with any questions or comments!
