In a more or less serious installation, you can find a separate external amplifier, and not one. Well, let's try to figure out what its advantage is - along the way we will get rid of some erroneous errors …
Those who are not too keen on audio often confuse two concepts - “powerfully” and “loudly”. The conclusion is: “I don’t listen to loud music, and, therefore, I do not need a powerful amplifier.” I would like to ask: if you do not drive under 250 km / h, you do not need a more powerful car? You object: powerful is not only the “maximum speed”, but also the dynamics of acceleration, due to which it is easier to maneuver … With the “music” - the same thing. For high-quality reproduction, the amplifier needs to work not at the limit of its capabilities, but with a margin so that, if necessary, energy could be thrown out, playing out a complex composition. The volume depends not only on the amplifier, but also on the speakers, their sensitivity, installation, etc.
On any modern head unit, you can see the numbers "4 x 50W" or even more. What - is it not enough? It depends on what and how to measure. The receivers indicate the maximum power that, in general, they can give out, but only at the peak of the signal (for a short time). At the same time, nonlinear distortions can reach about 10%, or even higher - this is no longer music. And to “kill” high-frequency acoustics in this mode is much simpler than a more powerful amplifier that works without distortion.
Any decent speakers can easily play two dozen watts given by the built-in amplifier of the receiver. But it’s 10–20 W, not 50! Within these limits, the rated power of modern head units fluctuates. Unlike the “maximum speed”, it is measured with fixed non-linear distortions, supply voltage and load. That is, this is the power at which music still remains music, rather than wheezing and squealing, giving out the treasured figures.
MONO, STEREO …
"Stereo" is not just two speakers. These are two columns, each of which plays its own part. Thanks to this, you can achieve realism and understand the location of the instruments on the stage. Typically, the receiver has four outputs: two for the rear speakers, two for the front. But this is not surround sound: the two rear speakers duplicate the front speakers exactly. This is far from the same as in home theater surround sound systems! In them, the rear speakers work independently, allowing you to achieve the effect of moving a bird along the perimeter of the room.
But do not get upset. If you recall the concert hall, the stage is always in front of you, but if you managed to get a ticket to the central sector, then here it is, the most pleasant listening point. Hence the conclusion: in a serious system, only front speakers are quite enough. The only negative - deprived rear passengers.
IN ORDER OF NUMBERS …
[caption id = "attachment_189819" align = "aligncenter" caption = "TWO CHANNEL AMPLIFIER LIGHTNING AUDIO B3.200.2 BOLT
Estimated price - $ 150. Output power 75x2 W at four-ohm load. When bridged, it is capable of delivering 200x1 watts. Built-in high-pass / low-pass filter adjustable within 40 "]
[/ caption] [caption id = "attachment_189820" align = "aligncenter" caption = "TWO CHANNEL AMPLIFIER ROCKFORD FOSGATE P550.2 PUNCH
Estimated price - $ 550. A serious model with considerable power - 150x2 W with a four-ohm load. When using a two-ohm load it is capable of delivering 275x2 W, and in the "bridge" everything is 550. Built-in "]
[/ caption] Two-channel amplifiers. In most installations, they are used to get a better and more powerful sound from a pair of speakers or one subwoofer. Why one? A subwoofer should only reproduce particularly low frequencies (usually below 60–100 Hz), and they are not known to be localized. Therefore, you can get by with one subwoofer connected simultaneously to two channels in mono mode (bridge connection). The result is power boost.
To "sub" played only ultra-low frequencies, use the low-pass filter (LPF) built into the amplifier. Without it, nothing - all the music will turn into a “buzz” from the trunk. With the rest of the acoustics, they do the opposite - remove the low ones. The most optimal option is when the frequency of the partition is not fixed, but can vary.
Are there single channel amplifiers? Yes, but rather as an “exotic option”: because of their non-universality, they are not widespread.
[caption id = "attachment_189821" align = "aligncenter" caption = "FOUR CHANNEL AMPLIFIER MAGNAT HOT ROD 4500
Estimated price - $ 250. A four-channel amplifier with a power of 80x4 / 240x2 W with a load of 4 ohms. With a two-ohm load, it produces 180x4 / 500x2 watts. The built-in high / low-pass filter is set in the pre "]
[/ caption] Unconditional record holders - four-channel amplifiers. They deserve their popularity precisely because of their versatility. The most common connection scheme is two channels to the front speakers and two channels to the subwoofer. We kill two birds with one stone: we connect both acoustics and a subwoofer, and if there is none, you can connect the rear speakers. And there is also the so-called “channel-by-channel” or “lane” connection - one pair of exits goes to the “tweeters”, the second goes to H4. True, in this case, more serious filters with wide adjustment possibilities will be needed.
We jumped over three-channel amplifiers. Yes, there are also such ones - the third channel is usually used to connect a subwoofer.
[caption id = "attachment_189822" align = "aligncenter" caption = "FIVE CHANNEL DLS RA50 AMPLIFIER REFERENCE SERIES
Estimated price - $ 600. Output power 70x4 + 265x1 W. Able to cope with a 2 ohm load on all channels. "On board" low / high pass filters, sabsonik and phase control. Inputs of “high”]
[/ caption] As for the five-channel amplifiers, then, in fact, these are the same four-channel with another channel for the subwoofer. If everything is clear with the “bass” channel, then the remaining four can be used both for the system with front and rear acoustics, and for the “channel”, but again, if filters allow.