Unique Cars - Car Audio feature

By Kevin Poulter


Car Audio Terminology
Understanding Car Audio Terminology.

Head Unit, Depth
The Head Unit is the radio itself with all controls. Depth is important when installing a radio. Best to avoid cutting a hole in the dash until you check the radio is not too deep for the position.

Watts
How do you understand watts? You don’t. Manufacturers once quoted power out in watts RMS, which was a good guide. But would you buy a 50 watt RMS amplifier or 1,000 watts peak? Most new buyers purchase equipment with the greatest power rating in their budget. However without a complete knowledge of the testing system and parameters like frequency, distortion and impedance, peak is not a reliable figure, especially in budget brands. You’ll see watts quoted as RMS, Max, Rated Power, Peak and others.

Distortion, Clipping
Low distortion ratings ensure you hear the music as intended. Rock and old tunes are more acceptable with say, up to 5 percent distortion (source+amp+speakers added together). Quality music equipment may be around 1 percent distortion at normal listening levels.
The worst distortion is Clipping - an amplifier overdriven - you want to avoid that as damage is likely.

Decibels and SPL
The Decibel (dB) is a measurement of sound pressure (SPL), loudness or volume levels, measured in a logarithmic scale. When comparing the frequency response of audio gear, the best have their frequency response quoted within +/- 3db or at most +/- 6dB. If the dB points are not quoted at all, the frequency response figure is at best just a broad guide.

SQ
Sound quality. Some car audio competitions judge SQ.

Amplifiers, multi-channel, bridged
In a multi-channel amplifier, two channels are connected to drive a single load. The input signal is split, then one of the signals is inverted. The non-inverted signal is sent to the left amplifier and the inverted signal to the right amplifier. The load is connected between the two outputs to receive twice the voltage. The resultant power is much greater than two 4-channels combined.
Multi-channel amplifiers often drive a subwoofer, front stage plus rear speakers.

Loudspeakers and Watts
Loudspeakers don’t have power output (even though this is regularly seen in print), rather maximum handling power. It’s vital to match the power of an amplifier to the speakers and the best way is to buy the same brand speakers manufacturers say matches their amp. If you choose a different brand speaker, it should have a matching power rating, or a little higher capacity. When a speaker is a much higher capacity (and/or higher impedance) then the amplifier needs to work harder, resulting in greater distortion, which can damage the amplifier or the speaker. Conversely, a speaker with a lower power rating than the amplifier (or lower impedance) can also damage either the amp or speaker.

Peak Input Power
The amount of power a voicecoil can withstand for short periods of time.

Subwoofers
The big sound, big bass speakers in a system. A wired amplifier driving a subwoofer can give an instant power bass boost to an existing system. The easiest upgrade is an amplifier and subwoofer in the one box or tube, called an Active subwoofer. An Active subwoofer box can be large, round, wedge, or slim enough to sit behind the driver’s seat or in the boot. This packaged subwoofer needs holding down with a belt - supplied or optional - as it can become mobile in an accident. One advantage is the box can be taken out to store at home, for security.
The subwoofer speaker itself is a big, rugged brute, capable of handling a lot of bass power and nothing else. The stronger the cone, voicecoil and frame (basket) the better.

Voicecoil
A coil of wire in the centre of a loudspeaker. When driven with music electrical energy, the big permanent magnet attracts or repels the coil attached to the speaker cone, according to the polarity of the music note at an instant in time.

Speaker Cone
Previously only made from pressed cardboard, it’s essential that the cone is rigid, to avoid unwanted sound distortion, yet flexible at the edges. So manufacturers make cones from materials like rigid polypropylene and even aluminium.

Driver
Alternate name for any loudspeaker.

Bass, Resonance and Low Pass
The low frequency sound. Bass is between 20Hz and about 400 Hz. Bass with a strong unwanted peak is called boomy. Low Pass Filter is a filter that stops all frequencies above a predetermined frequency. Frequencies below cut-off are passed without any effect.
Resonant Frequency is the frequency which a speaker cone vibrates the easiest - the point at which it has the most amplitude - rather like a muffler in resonance.

Midrange
This is sound in the voice range, about 200Hz to about 5kHz.

Treble
High sounds, usually in the 5-10 kHz band.

High Pass Filter (HPF)
A network of components which block all frequencies below a predetermined frequency. Frequencies above the cut-off are passed without any effect. For example a filter to protect a tweeter.

Coaxial Speaker
Coaxial speakers have a large cone for the low range, and a smaller tweeter for the high spectrum. Some include a midrange. There’s a cross-over network to divide the signal to the correct driver.

Component speaker
Designed for only sub, low, mid or treble range only. With a quality crossover, often the best.

Capacitor
An electronic device which stores energy and releases it when needed. Also used to direct high frequency sound to tweeters. Also used to remove interference or hum in power supplies. Rated in Farads or microfarads (uF).

Impedance, Resistance and Ohms
Measurement of the resistance to the audio current by the voice coil of a speaker. The DC resistance of a speaker differs to it’s actual rating as frequency and inductance come into the equation.

Class
Amplifiers are in different classes, like A, AB through to Class D, depending on how the biasing of the amplifier circuit is done. Class A can be top end quality, however recently designers made class D work really well, with best efficiency.

DIN
Deutsche Industrial Norm - a German spec. that indicates the size of a radio, widely used in Australia.

Ground and Ground Loop.
An electrical potential of zero. Most modern vehicles have a negative ground, with the metal frame being the vehicle's ground. Can be a friend or foe. Connecting an amplifier or audio cable to ground can increase or decrease hum, sometimes with little predictability. Ground Loop occurs when a voltage exists between two separate ground points.

Speakers in Phase
Loudspeakers sound way better when the speakers all move in and out on a note in unison, not three speakers moving out while one moves in, sucking some of the sound’s air pressure from the cabin. So many speakers are marked plus and minus, or their cable spades will only fit one way around. You’ll especially lose bass when a system is out of phase and even when using the manufacturer’s cable, it can happen if you cut and extend the cable incorrectly. Installers may check phase using a meter, though there are manual methods of checking too.

Enclosure or Baffle, Port
An enclosure is a speaker box, either sealed (infinite baffle), as most loudspeakers perform well in a sealed box, or subwoofer box with unique shape and tuned ports. Also known as a Bass Reflex vented enclosure. The enclosure and port both level out or reduce peaks (like resonance) in the frequency response. A Baffle is a flat panel, like a car door, that keeps the front and rear sound waves mixing with each other and nearly cancelling out quality sound. Before drilling any baffle hole, check the depth needed and if the window mechanism will hit the speaker. This is one of the main reasons why some installers make a door speaker assembly that protrudes out from the door’s flat panel.

Spades, bullets, connectors, crimping, RCAs
Spades and bullets are male and female connectors to join wires to devices. Some loudspeakers use flat pins like spades. Joining a spade connector to a wire is usually achieved by a crimping tool, rather than soldering. In fact it’s possible to complete an entire job without a soldering iron. Give all crimped connections a tug when finished, to see the bond is secure.
Like the RCA connectors at the back of home hi-fi and TVs, they are the round connector for low-level audio. Gold plated RCAs ensure a reliable connection for a long time. The cables come in different quality grades so choose more expensive over cheap, especially for long runs. Stinger make a top range of cables.

Front Stage
Considering live music performances are on stage in front of the audience, competition enthusiasts replicate that stage in their car. Alternatively drivers who just want to listen to good sound can have most sound from the rear, if that suits their ears. It also makes installation easier. Talk to competition entrants and they will strongly emphasise the need for major sound radiating from the front, but it’s really up to your taste.

Audio Frequency Spectrum
The band of sound frequencies extending roughly from 20Hz to 20kHz. As people get older, or have less keen hearing, they have trouble hearing beyond 15kHz (treble), though FM radio audio does not go above this and it’s easy to turn the treble up to compensate.

DSP
Digital Sound Processor, which can adjust tone curves and also make sound more like a performance in a particular area, like a concert.

Gauge
The cross-sectional area of cables. The cable supplied with a radio is the minimum recommended thickness. If in doubt choose a thicker gauge for speaker and power cables, for best power transference.


Dealers




Nostalgic Wireless

Nick King’s Nostalgic Wireless Company is most likely the only company in Australia that restores vintage car radios. He also has a range of vintage home radios. Most people bring their own car radio or send them from around Australia for repair.

New electronics or fully original?
It’s even possible to have a vintage radio changed inside to a modern AM/FM radio. Externally it supports the original look, yet has modern sound from the new electronics inside. This new “heart” can operate using the original controls on the radio, like fader, bass and treble and run up to four loudspeakers. Options include iPod input, Bluetooth, MP3 or even a CD Walkman input. If you prefer the radio restored as fully original, a FM module can be added with no change to original parts.

Nick’s tips - a problem can be external.
Nick receives radios that failed after their battery polarity was connected incorrectly, others with the wrong impedance or shorted speaker, or with shorted speaker wires in the car. An example: transistors have a preferred impedance, usually 15 ohms in older Aussie cars. The output transistors can be blown by adding 1 or 2 modern speakers, which can be as low as 1.5 ohms if wired in parallel. When the radio is fixed, if these external faults remain, the radio will blow again.

Aerials
Old aerials can stop receiving too, when rust or shorts result in no signal, or after re-chroming the aerial’s mast, then reassembling it incorrectly. Another tip: after repainting a car, ensure the aerial’s base has good contact to earth (car body). This may require scratching the paint back to bare metal underneath where it cannot be seen.

Nostalgic Wireless acquires radios worldwide and has a stock of 600+ radios, ranging from 1926 to 1980 - the cut-off era for their restorations.

Tel: 03 9499 2495

Click HERE for the Nostalgic Wireless Web Site




Click HERE for Alpine Electronics Site




Featured ALPINE Dealer - PERFORMANCE Car Audio Visual

Established over 23 years ago, Performance Car Audio Visual has evolved into an industry-leading car audio/visual and accessories supplier.

Business owner Brett Hill has more than 25 years experience within the industry and has a wealth of knowledge from early to late model vehicles.
Backed by the biggest brands and suppliers in the country, they can offer the right solutions for most applications.

Their workshop is equipped with the latest tools and equipment to assure that installations are carried out to the highest standard, with no obligation quotes and advice.

Contact (03) 9729 8133


Click HERE for their site






Click HERE for Fusion's site


FUSION Dealers

http://www.autobarn.com.au/coffs-harbour
http://www.autobarn.com.au/stores/bundall
http://www.autobarn.com.au/queensland/burleigh-heads
http://www.autobarn.com.au/stores/tweed-heads
http://www.autobarn.com.au/stores/bellbird-park
http://www.autobarn.com.au/stores/browns-plains
http://www.autobarn.com.au/queensland/virginia
http://www.autobarn.com.au/queensland/caboolture
http://www.autobarn.com.au/stores/kawana-waters
http://www.autobarn.com.au/stores/gympie
http://www.autobarn.com.au/queensland/rockhampton
http://www.autobarn.com.au/stores/mackay
Auto one Browns plains http://www.autoone.com.au/StoreLocator/StoreProfile.aspx?StoreId=53f2eb41-cce1-4aec-9feb-a8119ebbf409
Auto One Kawana http://www.autoone.com.au/StoreLocator/StoreProfile.aspx?StoreId=27bad266-cf3b-4517-8de7-c94f439e9d74
Cairns Sun Air & Sound http://csas.net.au/
http://soundinmotion.com.au/
http://www.pmrccs.com.au/
http://www.hirollercustoms.com.au/

NSW
www.xtremecaraudio.com.au
www.ryda.com.au
www.elitecaraudio.com.au
http://www.caraudioexcellence.com.au/
Auto One Campbelltown http://www.autoone.com.au/StoreLocator/StoreProfile.aspx?StoreId=a5fa1e7a-8f23-44a9-9f04-0b590fd85bbb
http://www.monstercaraudio.com.au/
http://stmaryscaraudio.com.au/
http://www.bodytechautomotive.com.au/
http://www.incaraudio.com.au/