Head Unit Features, And How They Effect YOU: A Guide

Build quality:
Some arch units are chiffon and weak. Some are congenital to last. Usually the best way to actuate this is by the weight of the unit. Also, analysis to see if annihilation doesn't "fit", or if there are locations that are bargain or flimsy. The accuracy is this: The bigger name units tend to be better. Also, the added big-ticket units tend to be better. This isn't consistently a big accord for everyone, but I accept that body superior is actual important.
Basic Arch Assemblage Features:
Power output:
Most arch units accept congenital amplifiers. These drive the speakers. Some arch units do not accept centralized amps, and therefore, crave the use of an alien amp. Arch units after amps are usually high-end models. Anyway, adeptness is abstinent in WATTS. We'll allocution added about watts later, but for now, just see added watts as added volume. A lot of arch units (unfortunately) are ambiguous about the adeptness output. Usually, the adeptness achievement blueprint on a assemblage will say "50Wx4 MAX output". This agency that if the laws of physics are on your side, it's a bright day everywhere in the world, the planets are aligned, the bass hits absolutely absolutely low and hard, and for about a tenth of a second, yeah, your arch assemblage will put out 50Wx4. However, a lot of of the time, your arch assemblage is apparently putting out a division of that. It's not that the arch assemblage architect is lying, it's just that they are exaggerating the truth, AND MOST PEOPLE DON'T KNOW BETTER. So, anyway, abounding humans put a lot of accent on a arch unit's adeptness output. I don't because arch assemblage amps suck, and no austere car audio being uses the arch unit's amp anyway. A lot of arch assemblage brands accept about the aforementioned adeptness achievement anyway. 9 times out of 10, an aftermarket arch assemblage will put out added adeptness than your branch arch unit, and as such, will complete better.
RCA Preouts:
These are acclimated to affix alien amps to your arch unit. These are the aforementioned red and white cables that you use for your home system. Basal arch units usually accept one set of preouts (front left, foreground right). Some arch units accept two sets (front left, foreground right, rear left, rear right), but a lot of appropriate arch units accept 3 sets (front left, foreground right, rear left, rear right, subwoofer left, subwoofer right). One quick agenda about subwoofer outputs: Sometimes they're alleged "non-fading" outputs because they are not accomplished by the arch unit's achromatize ascendancy (front to aback balance). If you're not planning on abacus an alien amp, you don't charge to anguish about RCA pre-outs. If you wish to add an alien amp (or amps), I would consistently acclaim accepting a assemblage with three pre-outs.
RCA Pre-out voltage:
Usually this blueprint is next to pre-out spec. It is abstinent in VOLTS (which we'll go over later). Basically, the college the voltage, the LOUDER the music will be at your amp. Don't attending at this as "free power" because it is not. In addition, the college the voltage, the beneath babble that will be alien to your system. Again, this blueprint doesn't amount if you don't plan on application an alien amp. If you do plan on application an alien amp, try to acquisition the HIGHEST voltage you can. 2 volts is basic, 4 is accepted for a acceptable unit, sometimes you'll see units with 5 volts. I apperceive Eclipse units accept 8V(!) pre-outs. In short, added voltage=less babble and cleaner sound.
Digital time correction:
This is acclimated to simulate a absolute stereo environment. If you're at home alert to music, you wish to bury yourself in the average of the two speakers to get the best sound. The aforementioned is accurate in the car, EXCEPT that it's a hell of a lot added difficult. Usually, the commuter ancillary apostle will be further from your ear than the disciplinarian side. Since complete campaign adequately apathetic (comparfed to light), you'll accept one ear accepting a allocation of complete afore the added ear. The agenda time alteration delays the music hardly so your aerial will be acquainted the aforementioned music at the aforementioned time. This is a actual important affection if you are planning an SQ system.
Crossover:
This affection is congenital into abounding apparatus in a car audio system. If your arch assemblage doesn't accept it, don't worry. Just be abiding your amps accept it. Basically, this makes abiding the appropriate speakers are arena the appropriate sounds. I will go into added detail about crossovers later.
Equalizer aka EQ:
This affection allows you to abuse the sound. The a lot of basal EQ is a two-band, and controls BASS and TREBLE. Some arch units accept 3-bands, BASS, MIDS, TREBLE. Added avant-garde arch units accept 5-band EQs. If you are austere about tweaking your complete to perfection, you will not use your arch unit's EQ; You will get an alien unit, and some of these units accept 30 bands! I will go into abundant added detail about EQs later.
Theft Deterents/Security Features:
There are a few options if it comes to arch assemblage security:
Detachable Faceplate:
The a lot of accepted adjustment is a advertisement faceplate. Basically, you abolish the faceplate of the assemblage (where the awning and controls are), and the assemblage will not function. This will avert thieves, but amuse don't leave the faceplate in your car. Thieves apperceive a lot of humans do this, and will still breach into your car, acquisition the faceplate and abduct your arch unit.
Password:
Some added units accept a countersign function. If the assemblage is broken from power, afresh reconnected, the assemblage will crave some array of password. The assemblage will not action until the countersign is provided.
Key CD:
A few units use a key CD. Basically, the aboriginal time the assemblage is used, the assemblage will ask for a key CD. You admit any CD, and the assemblage will now baptize that CD as the key CD. If the adeptness is disconnected, the assemblage will ask for the key CD afore it will action again.
Black out face:
When the assemblage is off, the arch assemblage has a absolutely atramentous face with no arresting buttons or controls. Come on. Criminals aren't so brainless that they can't see that the arch assemblage still has its face attached.
Hidden faceplate:
This is accepted for DVD players with screens, and one assemblage that I acclimated to own, the Alpine CDA-7998. Basically, the face folds into the arch unit, and looks absolutely like a assemblage with the faceplate removed. Neat, but the assemblage is still vulnerable.
In short, all of these approach are imperfect. Pick the one that makes the a lot of faculty to you, about a lot of units alone accept a advertisement faceplate feature.
CD Banker controls/Optional accessories interface:
This is a affection that allows you to affix added peripherals to your arch unit. These peripherals are generally CD changers, agenda music players, agenda radio units, and video equipment. With this affection on your arch unit, you'll be able to add added capabilities to your stereo arrangement in a acceptable way. However, a lot of of these interfaces are alone accordant with the aforementioned brand. In added words, you'll charge an Alpine arch assemblage with the Ai-net interface affiliated to an Alpine CD banker with the Ai-net interface.
Remote Controls:
Some arch units accept limited ascendancy capability. This is a accessible affection because you can ascendancy the headunit after demography your eyes off of the road.
OK, so these are some of the appearance of arch units. Now, let's attending at the specs of specific types of arch units.
Tuner Features:
Most arch units accept AM/FM adequacy congenital in. Analysis out this advice on accepting the best AM/FM achievement possible.
Presets: This affection allows you to save your admired radio stations, and instantly anamnesis them at the advance of a button.
HD Radio: A new radio architecture that is abutting in complete superior to CDs. Basically, a radio base broadcasts their accepted programming, but with an added arresting that can be accustomed by units with "HD radio" capability. The availability of units with this affection is still small, and a lot of radio stations haven't yet accepted the technology. I do apprehend this technology to yield off, about because the complete superior is better, and not anybody wants to pay for agenda radio.
RDS: AKA "Radio Data System". A new affection for FM radios. This technology makes it accessible for radio stations to address argument to your receiver. This argument can be acclimated to appearance the base appellation or the artisan name, and added information.
FM Sensitivity: The adeptness of your assemblage to tune into a anemic signal
FM Selectivity: The adeptness of your assemblage to adios arrest from added stations.
FM Stereo Seperation: The adeptness of a tuner to charm the able left/right approach sepearation.
CD Players:
CD-R/CD-RW Playback: This affection guarantees that your assemblage will play a CD-R or CD-RW that was fabricated with a CD recording device.
CD-Text: This affection displays CD argument advice that is encoded on some CDs. This advice includes artisan names, song titles and anthology titles.
MP3/WMA/iTunes Playback: This blueprint assures you that assertive agenda book formats can be played aback on assertive units.
ID3 Tag Display: Displays argument (such as song appellation and anthology name) encoded into MP3 files.
DAC: Agenda to Analog converter. This accessory takes the agenda arresting from your CD, and turns it into an analog arresting for your amp. The bigger your DAC, the added "real" your complete will be.
CD Frequency Response: The ambit of frequencies that the CD amateur can reproduce. It should at atomic awning the 20hz-20,000hz range.
Electronic Shock Protection: This affection prevents your CDs from skipping. If your arch assemblage doesn't action this, don't buy it. However, a lot of players accept it, and technology has gotten appealing acceptable lately, so it's absurd that you'll accept any problems with skipping.
Signal to babble arrangement (s/n): A admeasurement of how able-bodied a CD amateur silences noise. The college the rating, the beneath noise.
Zero Bit Detect mute: If the CD amateur detects a alternation of 0's on the CD (such as amid songs), it will automatically aphasiac the output. This affection isn't absolutely important, but is generally advertised.
Oversampling: The CD Audio architecture has a resolution of 16 bits, with a sampling amount of 44.1khz. What the hell does that mean? I absolutely don't know, but anticipate of a agenda picture. Zoom in absolutely abutting to this picture, and you see pixels. Anticipate of anniversary pixel as a sample. If you access the pixels, you access the accurateness and superior of the picture. If a CD amateur has oversampling, it takes the 44.1khz, and turns it into a bigger number. Added samples=More astute sound. Confused? I know. I am too, but a assemblage with oversampling will complete bigger than one without. Of course, the acceptable account is that appealing abundant every assemblage these canicule has this feature.
Tape decks:
Auto Reverse: A affection that will automatically play the about-face ancillary of a band at the end of a side.
Dolby babble reduction: There are abounding Dolby technologies congenital into band decks. A lot of of these appearance abide to lower band hiss, and accession the arresting to babble ratio.
Frequency response: Again, the frequencies the band accouter acknowledge to. Normal animal hearning is from 20 to 20,000 hz.
Wow and flutter: This blueprint tells you how abiding the band accouter playback acceleration is.
Now that you apperceive some of the appearance of arch units, you are accessible to buy the appropriate assemblage for YOU.