Questioni recently asked you a question concerning my new stereo system that i am going to put in my car. Your answer was very helpful, thakyou. I am looking to buy the right head unit and was wondering if this head unit: http://www.amazon.com/Boss-Audio-720CA-Receiver-Detachable/dp/tech-data/B0015AQL... would work for a system with:
1 sub w/an amp
2 front + 2 rear speakers all hooked up to a 4-way amp
i also am a little confused on if an RCA output is the same as a preamp output, many head units are listed to have front and rear RCA outputs, but if my speakers are connected to an amp do they need to be front and rear preamp outputs? I am a little confused on the lingo.
thanks for all of the help, it is much appreciated
AnswerHi Andrew,
"RCA output" means the same thing as "pre-amp output" or "pre-out".
Basically, head units have two kinds of outputs: speaker level or low level. The speaker level outputs use the built-in amplifier, and the low-level outputs do not, which is why they're called "pre-amp". The reason they're also called "RCA outputs" is because the type of plug used for the pre-amp output is called an RCA plug. In modern head units, any output that uses RCA jacks is a pre-amp output.
A 4-channel amp has four separate inputs: left and right front, and left and right rear. If your head unit has separate front and rear pre-amp outputs, then you'll have a separate output for each of the amplifier's inputs. That's ideal. If you only had a single set of outputs, then you'd only have two outputs on the head unit for the four inputs at the amp. In most cases, you'd have to use RCA splitters to connect the four inputs to the two outputs. The disadvantage of doing this is that you'd lose the ability to "fade" the volume from front to rear. You can't make the front speakers softer and the rear speakers louder, because both front and rear would be using the same output at the deck.
When you add a subwoofer amp, then you're taking it a step further. If you have front and rear outputs, but no sub output, then you can't adjust the volume of the sub relative to the front and rear speakers. You can still make the sub work (using RCA splitters, or an RCA output at the 4-channel amp) but you'd lose the ability to control the sub directly, because it's sharing the head unit's front or rear output.
As for the Boss head unit in your link, it appears to have front and rear outputs, but not a subwoofer output. (Technically, the rear output can be converted to a subwoofer output). With this deck, you'd have to choose between giving up the fader control or giving up the sub volume control. If you can find a deck with separate front, rear and subwoofer outputs, that would be better; but it may be hard to find one in this price range.
I hope this is helpful.
Brian
