Articles by Professor Apex on ArticleSnatch.com

AUTOMOBILE STEREO WOOFER BOXES

Tue, 30 Sep 2008 00:00:00 -0400

Enclosures for Car Stereo Woofers: Because woofers move a lot of air they generate a back wave behind them. If you mount a woofer in free space without an enclosure you will get almost no bass because the back wave will cancel out the sound from the front of the woofer. There are many varieties of types of enclosures for woofers to handle this backwave. A common one is a ported box. This enclosure has the woofer mounted in box with a hole in it and a port (tube) attached to the hole. The port is made a specific size and depth to cause a "bump" or rise in the frequency response at that point. This makes the overall system more efficient but can cause the bass to be somewhat "boomy" or less "tight" depending on how its done. A newer technique is a bandpass enclosure. The woofer is mounted inside the box and fires into another chamber within the box that is ported to the outside. Again, this increases efficiency greatly but only at a certain frequency. This effect can make the system very loud and boomy. **End Summary** Topics: car audio]]> car stereo]]> car subwoofers]]> automobile subwoofers]]> car woofer boxes]]>]]> About the Author: ]]> Professor Apex is an Expert In Car Audio and Car Video. He has more than 13 years of experience.

CAR AUDIO MISCELLANEOUS

Tue, 23 Sep 2008 00:00:00 -0400

What is Alternator Noise? Alternator noise is a high pitched whine created by the car's electrical system. If the engine spins quicker, noise frequency is higher. That is why you would hear alternator noise coming from mids and tweeters, but not subwoofers, since subwoofers only play low frequencies. What causes alternator noise? 1. Induced noise through RCA's: When a wire has current through it, a magnetic field circles around it (i.e electromagnets). Conversely, if there is a magnetic field perpendicular to a wire, current will be induced. If you have your RCA wires from the radio or equalizer to the amp running in parallel to your power wires, an AC current will be induced and added to the sound signal. The sound signal travelling to the amp is a low voltage signal (in the mV range - thousands of a volt). The induced signal will be amplified along with the music. Avoiding this problem is very simple: DON'T run power and RCA wires together. If there are points in which they do have to cross, try to place them perpendicular to one another. **End Summary** Topics: car audio]]> car stereo]]> miscellaneous]]>]]> About the Author: ]]> Professor Apex is an Guru In Car Stereo and Car Video. He has more than 12 years of experience.

AUTOMOBILE SPEAKERS SPEAKERS

Fri, 19 Sep 2008 00:00:00 -0400

Speakers Overview: The car audio you use will have the final say in how your system will sound. There are many different types of speakers available. A single speaker can be used to reproduce the full range of sounds but it is not ideal. If the speaker is too large it will have problems reproducing high frequencies which require rapid movement of the speaker. If it is too minute it will have problems reproducing low frequencies which require large amounts of air to be moved. Because a single speaker cannot reproduce all sounds accurately multiple speakers are used each of which reproduces sound in the frequency range it was designed for. A speaker called a tweeter reproduces high frequencies generally above 2 kHz. Tweeters are small and lightweight so they can respond fast. Very little power is required for powering tweeters because they are very efficient. Woofers are the exact opposite because they usually require considerable amounts of power to really move air. Woofers are meant to produce sound at frequencies below 250 Hz and often just below 100 Hz (in the case of subwoofers). **End Summary** Topics: car audio]]> car stereo]]> car speakers]]> automobile speakers]]>]]> About the Author: ]]> Professor Apex is an Expert In Car Stereo and Mobile Video. He has more than 10 years of experience.

CAR STEREO SYSTEMHEAD UNITS

Sat, 13 Sep 2008 00:00:00 -0400

Head Units Overview Ideally, your head unit would be used to provide a signal to your amplifiers that is line level and you would not use its internal amplifiers (if any). They typically do not have the power and strength to drive speakers both loudly and cleanly. The line level signal is clearer than the speaker level outputs on the head unit because it is does not go through the internal amplifiers in the head unit. That being said there are times where you would use the head unit's internal power. One situation is to save money and the other situation is when you are building a system where the benefits of an amp are not key to you. Read my planning page for more details about what is right for you. No head unit usuallyhas more than about 60watts of total output power because more would require a real DC-DC power supply (which does not fit in a head unit easily). **End Summary** Topics: car audio]]> car stereo]]> head units]]>]]> About the Author: ]]> Professor Apex is an Expert In Car Stereo and Car Video. He has more than 13 years of experience. You can find him here: Wholesale Car Audio

AUTOMOBILE SUBWOOFERS

Sat, 13 Sep 2008 00:00:00 -0400

Subwoofer Definition: A loudspeaker designed to reproduce bass frequencies. Subwoofer Selection Tips When deciding to upgrade your audio system, adding a subwoofer can improve performance. Adding volume at sub frequencies is like adding a third dimension to your music. Whether youâ€'re thinking about building a new audio system, or just adding one (or more) subwoofers to your factory system, this addition will give you the single, largest sonic improvement. Adding even a little bass gives a huge improvement. Selecting a subwoofer can be confusing. There are a few questions that you should ask yourself before actually running out and buying woofers. What type of sound are you looking for? There are two main camps in the sound world: Sound Quality (SQ) or Sound Pressure Level (SPL). Sound Quality refers to just that.. An SQ System generally uses a smaller woofer and requires a smaller enclosure. A sealed enclosure would typically work best for this application. SPL, alternatively, is for you Big Bass Lovers.â€ Sealed enclosures are also referred to as Acoustic Suspensionâ€ enclosures. **End Summary** Topics: car audio]]> car stereo]]> car subwoofers]]> automobile subwoofers]]>]]> About the Author: ]]> Professor Apex is an Expert In Car Stereo and Car Video. He has more than 13 years of experience.

CAR AUDIO SIGNAL PROCESSING

Sat, 13 Sep 2008 00:00:00 -0400

Equalizers/Crossovers Basics Equalizers enable you to fine tune your system. It is hard to get speakers to reproduce sound flawlessly. Multiple speaker system things are even more involved. With an equalizer you can increase or reduce certain frequency ranges to tailor the overall sound to whatever you desire. An electronic crossover divides a signal into separate frequency ranges. The most common types are 2-way or 3-way. A 2-way crossover divides the frequency range in half at some cutoff frequency. All signals below the set frequency are routed to a low pass pre-amp output and the rest are sent to a high pass output. These outputs can be connected to amps to dedicate those amps to producing only those frequency ranges. A 3-way crossover is similar but splits the signal into 3 parts. You can get a single system with both an equalizer and a crossover. Electronic or active crossovers act on pre-amp level signals. They use the pre-amp level output of your head unit as input and their outputs go to your amp(s). By doing this you keep the amp from trying to amplify frequencies that you do not want (like high frequencies for a sub amp). **End Summary** Topics: car audio]]> car stereo]]> signal processing]]>]]> About the Author: ]]> Professor Apex is an Expert In Car Stereo and Car Video. He has more than 11 years of experience.

CAR AUDIO SPEAKERS

Sat, 13 Sep 2008 00:00:00 -0400

Speakers Overview: The car speakers you use will have the absolute say in how your system will sound. There are many different types of speakers available. A single speaker can be used to reproduce the full range of sounds but it is not ideal. If the speaker is too great it will have problems reproducing high frequencies which require rapid movement of the speaker. If it is too diminutive it will have problems reproducing low frequencies which require large amounts of air to be moved. Because a single speaker cannot reproduce all sounds accurately multiple speakers are used each of which imitates sound in the frequency range it was designed for. A speaker called a tweeter reproduces high frequencies generally above 2 kHz. Tweeters are small and lightweight so they can respond fast. Very little power is required for powering tweeters because they are very efficient. Woofers are the exact opposite because they usually require considerable amounts of power to really move air. Woofers are meant to produce sound at frequencies below 250 Hz and often just below 100 Hz (in the case of subwoofers). **End Summary** Topics: car audio]]> car stereo]]> car speakers]]> automobile speakers]]>]]> About the Author: ]]> Professor Apex is an Expert In Car Audio and Car Video. He has more than 10 years of experience.

CAR STEREO ACCESSORIES

Sat, 13 Sep 2008 00:00:00 -0400

Installation Accessories There are multitude of accessories that are available for your car stereo. Some of them are necessary such as RCA cables and others are elective like wiring harnesses. RCA Cables: These are the cables required used to transfer pre-amp (line level) signals. Usually, you use this type of cable for unamplified signals such as the connection between your head unit and amp or crossovers/eqs. Look for appropriate thickness and shielding. The end connectors should be sturdy to prevent breakage from stress. There is a notion that more expensive the cable, better the sound quality. However do not spend more than $1/foot. You may need to spend more to get cables immune to noise if that is a problem in your car. Speaker Cables: When the line level signal from the head unit is amplified it becomes more powerful and requires thicker cable to carry it. This is even more pronounced for subwoofer wiring. Use something between 9 gauge and 1415 gauge wiring for subwoofers, nothing smaller. A lot of current has to flow through those wires. For tweeters and midranges thickness is less critical but still important to prevent leakage and contamination from outside sources. **End Summary** Topics: car audio]]> car stereo]]> accessories]]>]]> About the Author: ]]> Professor Apex is an Expert In Car Audio and Car Video. He has more than 13 years of experience.

CAR AUDIO SYSTEMHEAD UNITS

Tue, 09 Sep 2008 00:00:00 -0400

Head Units Overview In a perfect world, your head unit would be used to provide a signal to your amplifiers that is line level and you would not use its internal amplifiers (if any). They typically do not have the power and strength to drive speakers both loudly and cleanly. The line level signal is cleaner than the speaker level outputs on the head unit because it is does not go through the internal amplifiers in the head unit. That being said there are situations where you would use the head unit's internal power. One situation is to save money and the other situation is when you are building a system where the benefits of an amp are not important to you. No head unit generallyhas more than about 60watts of total output power because more would require a real DC-DC power supply (which does not fit in a head unit easily). Using the head unit power can be a temporary solution till a separate amplifier can be purchased, just make sure you do not try to power any subwoofers or insensitive component sets with the head unit's built in power. **End Summary** Topics: car audio]]> car stereo]]> head units]]>]]> About the Author: ]]> Professor Apex is an Expert In Car Stereo and Car Video. He has more than 13 years of experience. You can find him here: Wholesale Car Audio

Planning Your Car Stereo System

Tue, 09 Sep 2008 00:00:00 -0400

Planning Your System This part of the game can be interesting or disappointing depending on what you can do. First I'm going to give you an example system that I believe includes everything you need to have a pretty good system. After that I will show you how to make trade offs and leave out parts that may not be as key to you to keep your system within your budget. I am describing a basic system, to go beyond that is past the scope of this book. Also, you do not have to get everything at once. I put my system together over a few years. With a little planning you can upgrade your system in steps and that way its like getting a brand new system every time you change something instead of getting everything at once! Basic System: This is my opinion only but I feel that a excellent system should start off with a good head unit that either has a CD player and/or is connected to a CD changer. A excellent system sounds best when playing CDs, tapes just do not cut it. **End Summary** Topics: car audio]]> car stereo]]> planning your car audio system]]> planning your car stereo system]]>]]> About the Author: ]]> Professor Apex is an Guru In Car Stereo and Mobile Video. He has more than 11 years of experience.

CAR AUDIO WOOFER BOXES

Sun, 07 Sep 2008 00:00:00 -0400

Enclosures for Car Audio Woofers: Because woofers move a lot of air they generate a back wave behind them. Mounting a woofer in a open space without an enclosure will cause a loss of bass as the back wave cancels the sound from the front of the woofer. There are many varieties of types of enclosures for woofers to handle this backwave. A popular one is a ported box. This enclosure has the woofer mounted in box with a hole in it and a port (tube) attached to the hole. The port is made a specific size and depth to cause a "bump" or rise in the frequency response at that point. This makes the overall system more efficient but can lead to the bass to be somewhat "boomy" or less "tight" depending on how its done. A newer technique is a bandpass enclosure. The woofer is mounted inside the box and fires into another chamber within the box that is ported to the outside. Again, this increases efficiency significantly but only at a certain frequency. This effect can make the system very loud and boomy. **End Summary** Topics: car audio]]> car stereo]]> car subwoofers]]> automobile subwoofers]]> car woofer boxes]]>]]> About the Author: ]]> Professor Apex is an Expert In Car Audio and Car Video. He has more than 12 years of experience.

CAR STEREO SPEAKERS

Fri, 05 Sep 2008 00:00:00 -0400

Speakers Overview: The car audio you use will have the final say in how your system will sound. There are many different types of speakers available. A single speaker can be used to reproduce the full range of sounds but it is not ideal. If the speaker is too large it will have problems reproducing high frequencies which require rapid movement of the speaker. If it is too modest it will have problems reproducing low frequencies which require large amounts of air to be moved. Because a single speaker cannot reproduce all sounds accurately numerous speakers are used each of which reproduces sound in the frequency range it was designed for. A speaker called a tweeter reproduces high frequencies generally above 2 kHz. Tweeters are small and lightweight so they can respond fast. Very little power is required for powering tweeters because they are very efficient. Woofers are the exact opposite because they usually require considerable amounts of power to really move air. Woofers are meant to produce sound at frequencies below 250 Hz and often just below 100 Hz (in the case of subwoofers). **End Summary** Topics: car audio]]> car stereo]]> car speakers]]> automobile speakers]]>]]> About the Author: ]]> Professor Apex is an Expert In Car Stereo and Mobile Video. He has more than 13 years of experience.

CAR SUBWOOFERS

Fri, 05 Sep 2008 00:00:00 -0400

Subwoofer Definition: A loudspeaker created to reproduce bass frequencies. Subwoofer Selection Tips When deciding to upgrade your audio system, adding a subwoofer can produce massive results. Adding volume at sub frequencies is like adding a third dimension to your music. Whether youâ€'re considering building a new audio system, or just adding one (or more) subwoofers to your factory system, this addition will give you the single, largest sonic improvement. Simply adding even a little bass will make a HUGE improvement. Iâ€'ll never forget my first experience listening to the heart-pumping sound of bass. I was listening to my friendâ€'s newly-installed system (he had a couple of 12â€'s with a decent size amps), and it was literally shocking how natutal it sounded, how you could actually feel the music. I was completely amazed that you could actually feel the impact of the woofers. From that moment on, Iâ€'ve been a car audio fanatic. Choosing a subwoofer can be difficult. There are a few questions that you should ask yourself before actually running out and buying woofers. What quality of sound are you looking for? There are two main camps in the sound world: Sound Quality (SQ) or Sound Pressure Level (SPL). **End Summary** Topics: car audio]]> car stereo]]> car subwoofers]]> automobile subwoofers]]>]]> About the Author: ]]> Professor Apex is an Expert In Car Audio and Mobile Video. He has more than 13 years of experience.

CAR AUDIO ACCESSORIES

Fri, 05 Sep 2008 00:00:00 -0400

Installation Accessories There are multitude of accessories that are available for your car stereo. Some of them are madatory such as RCA cables and others are optional like wiring harnesses. RCA Cables: RCA cables are needed to transfer pre-amp (line level) signals. Usually, you use this type of cable for unamplified signals such as the connection between your head unit and amp or crossovers/eqs. Its important to find the right thickness and shielding. The end connectors should be sturdy to prevent breakage from stress. There is a belief that expensive cable makes a difference in sound quality. However do not spend more than $1/foot. You may have to spend more to get cables immune to noise if that is a problem in your car. Speaker Cables: When the line level signal from the head unit is amplified it becomes more powerful and requires thicker cable to carry it. This is even more dramatic for subwoofer wiring. Use something between 9 gauge and 1415 gauge wiring for subwoofers, nothing smaller. A lot of current has to flow through those wires. For tweeters and midranges thickness is less critical but still key to prevent leakage and contamination from outside sources. **End Summary** Topics: car audio]]> car stereo]]> accessories]]>]]> About the Author: ]]> Professor Apex is an Expert In Car Stereo and Car Video. He has more than 12 years of experience.

CAR STEREO SIGNAL PROCESSING

Fri, 05 Sep 2008 00:00:00 -0400

Equalizers/Crossovers Basics Equalizers enable you to fine tune your system. It is difficult to get speakers to reproduce sound flawlessly. Multiple speaker system things are even more complex. With an equalizer you can boost or cut certain frequency ranges to tailor the overall sound to whatever you desire. An electronic crossover takes a full range signal and divides it into different frequency ranges. Usually crossovers come in 2-way or 3-way. You can get a single system with both an equalizer and a crossover. Electronic or active crossovers act on pre-amp level signals. They use the pre-amp level output of your head unit as input and their outputs go to your amp(s). By doing this you keep the amp from trying to amplify frequencies that you do not want (like high frequencies for a sub amp). On the other hand, a passive crossover acts on the signals after they have been amplified, they are connected after the amp and before the speakers. Things to look for: Number of Bands in the EQ: The number of bands in an equalizer tells you how fine an adjustment you can make. **End Summary** Topics: car audio]]> car stereo]]> signal processing]]>]]> About the Author: ]]> Professor Apex is an Guru In Car Stereo and Car Video. He has more than 11 years of experience.

CAR STEREO WOOFER BOXES

Fri, 05 Sep 2008 00:00:00 -0400

Enclosures for Car Audio Woofers: Because woofers move a lot of air they generate a back wave behind them. Mounting a woofer in a open space without an enclosure will cause a loss of bass as the back wave cancels the sound from the front of the woofer. There are many varieties of types of enclosures for woofers to handle this backwave. A common one is a ported box. This enclosure has the woofer mounted in box with a hole in it and a port (tube) attached to the hole. The port is made a specific size and depth to cause a "bump" or rise in the frequency response at that point. This makes the overall system more efficient but can lead to the bass to be somewhat "boomy" or less "tight" depending on how its done. A newer technique is a bandpass enclosure. The woofer is mounted inside the box and fires into another chamber within the box that is ported to the outside. Again, this increases efficiency significantly but only at a certain frequency. This effect can make the system very loud and boomy. The oldest and most popular type is a sealed enclosure. **End Summary** Topics: car audio]]> car stereo]]> subwoofer boxes]]> woofer boxes]]>]]> About the Author: ]]> Professor Apex is a Guru In Car Audio and Car Video. He has more than 10 years of experience. You can find more free articles here: Wholesale Car Audio .

CAR STEREO REFERENCE MATERIAL

Fri, 05 Sep 2008 00:00:00 -0400

Car Audio Dictionary: A: Attenuation, loss of dB. AC (Alternating Current): An electrical current that intermittently changes in amplitude and direction. Acoustic Fiberglass: Thin fiberglass material used as damping material inside speaker enclosures. Acoustics: The study of sound. Air Gap: The space separating the top plate and the pole piece. This is where the voice coil sits. Alignment: A class of enclosure parameters that gives optimum performance for a woofer with a given value of Q. Alpha: In sealed enclosure designs, the ratio of Vas to Vb, where Vb is the volume of the box you will build. Alternator: A device that is turned by a motor to produce AC voltage, which is then rectified (turned into DC) and used to supply voltage to the vehicle's electrical system. Ampere (A): The unit of measurement for electrical current in coulombs per second. There is one ampere in a circuit that has a one ohm resistance when one volt is applied to the circuit. Amplifier: An electrical circuit designed to boost the current, voltage, or power of an applied signal. Amplitude: The relative strength (usually voltage of a signal). **End Summary** Topics: car audio]]> car stereo]]> reference material]]>]]> About the Author: ]]> Professor Apex is an Guru In Car Audio and Mobile Video. He has more than 13 years of experience.

Amplifiers

Fri, 05 Sep 2008 00:00:00 -0400

Amplifier Overview Your amplifier takes the signal from your head unit and makes it big enough to be able to drive your speakers. It is good to use separate amps for high and low frequencies but it is not needed. The problem with using one amp for all frequencies is that you cannot adjust the levels among different frequency ranges as easily as you can adjust outputs of separate amps. Most people start their system with an amplifier for the low frequencies (bass) and use their head units built-in power to drive the higher frequency speakers. This is enough but the built-in power in a head unit is usually not strong enough for high volume listening and not clean enough for the discerning ear. There are lots of choices when choosing an amplifier. Things to look for: RMS Power: The power output of an amplifier should be roughly matched to what the amp will be used for and what speakers it will be driving. Oddly enough, the most usual problem with matching speakers and amps is using an amp that is too weak to power the speaker. **End Summary** Topics: car audio]]> car stereo]]> car amplifiers]]> amplifiers]]>]]> About the Author: ]]> Professor Apex is an Expert In Car Audio and Car Video. He has more than 12 years of experience.

CAR STEREO MISCELLANEOUS

Sun, 31 Aug 2008 00:00:00 -0400

What is Alternator Noise? Alternator noise is a high pitched whine created by the car's electrical system. If the engine spins faster, noise frequency is higher. That is why you would hear alternator noise coming from mids and tweeters, but not subwoofers, since subwoofers only play low frequencies. What causes this alternator noise? 1. Induced noise through RCA's: When a wire has current through it, a magnetic field circles around it (i.e electromagnets). Conversely, if there is a magnetic field perpendicular to a wire, current will be induced. If you have your RCA wires going from the radio or equalizer to the amp running in parallel to your power wires, an AC current will be induced and added to the sound signal. The sound signal travelling to the amp is a low voltage signal (in the mV range - thousands of a volt). The induced signal will be amplified along with the music. To avoid this donâ€'t run power and RCA wires together. If there are points in which they do have to cross, do the level best to place them perpendicular to one another. **End Summary** Topics: car audio]]> car stereo]]> miscellaneous]]>]]> About the Author: ]]> Professor Apex is an Guru In Car Audio and Mobile Video. He has more than 12 years of experience.