Zak: When you’re shopping for an amplifier,
the first question to ask yourself is, how am I going to use it? Am I going to power a sub or two subs with best cheap amplifier car.  One pair or two pairs of speakers? Or maybe subs and speakers? Knowing this helps you make the first decision:
which type of amp to buy based on how many output channels and how much power you need. So then let’s take a look at the different
types of amplifiers based on the number of output channels they have. Mono amps have one output channel. They’re usually used to power subwoofers,
and depending on the amp and the impedance of the subwoofers you can connect one, two
or even more subs to just one mono amp. Ken: Two-channel amps offer more versatility. You can use the two outputs to power a pair
of speakers, like the ones in your car’s front doors. And most two-channel amps can also be bridged. This combines the output of the two channels
into a single channel. It’s a great way to power a subwoofer. Zak: Four-channel amps give you the most options. They’re perfect for powering a couple pairs
of speakers. You can also enjoy the best of both worlds
by using two of the amps channels to power a pair of full-range speakers in the front
of the car, while bridging the output of the other two channels to drive the sub. You’ll get clean highs and powerful lows out
of one package. Amplifiers don’t stop at four channels, though. Five-channel amps let you power your entire
speaker system with just one amplifier. They have four channels for powering your
front and rear speakers and a fifth higher powered channel for powering your subwoofers. Plus a five-channel amp takes up less space
and it’s easier to install than two separate amplifiers. The five-channel amp is a good investment
if you want to build a system that has a lot of flexibility and room to grow. Ken: You know, one of the questions our advisors
get a lot is ‘How much power should my amp have?’ Zak: That’s a really good question. It’s important, though, before you start comparing
amp power ranges, that you don’t compare apples to oranges. There’s two different kinds of power ratings
out there: peak power and RMS power. Ken: Peak power is what the amp can produce
for a very limited burst of power. It’s often the number you’ll see on the box,
but it’s not very useful. It’s better to look at RMS ratings. Zak: RMS power is the measure of the amp’s
continuous power output. It’s much better to look at the RMS numbers
when you’re shopping. Ken: And if you really want to be sure about
an amps power rating, compare amps that have a CEA-2006 power rating. Now this standard establishes specific guidelines
for how the amp’s power is measured. So amps with this kind of power rating have
all been measured on a level playing field. Zak: But once you’re aware of all this, you
still need to figure out just how much power you need to drive your speakers. The first thing to remember is that it’s better
to have more power. Ken: Right. You want your amps to be able to play all
your music loud and soft without distortion, and be able to handle subtle changes in volume
easily. Zak: Yeah, and more power gives you just that. It’s something that we call headroom. Ken: As a starting point, consider the RMS
power ratings of your speakers or subs. Match, or better yet exceed, the speaker power
ratings with your amplifier. Zak: For example, to get that headroom, if
you have a subwoofer that handles 200 watts RMS power it with an amp that puts out 250
watts RMS. Ken: It will drive it cleanly and without
distortion, especially when the volume is cranked. And it will do it better than an amp with
less power. More power is always better. Zak: Depending on the kind of amp you’re getting,
and how you’re going to use it, there are some features built into most amps that you
should think about while you’re shopping. Ken: These can include high- and low-pass
filters, bass boost and speaker-level inputs. High- and low-pass filters have an important
job to do. They make sure that your amp is only boosting
the frequencies that you want it to. High-pass filters strip away the low frequencies
from the signal the amp is boosting. You’ll use the high-pass filter when the amp
is powering smaller speakers, like those in the front doors of your car. This way, your amp will direct its energy
to making the vocals and the instrumentals sound their best. Zak: Low-pass filters do just the opposite. They take out the highs so you’re only amplifying
the lows. You’ll want a low-pass filter when you’re
using the amp for powering a sub. That way, the amp can concentrate its power
on kicking out the low notes. Ken: We should mention one other type of filter:
the subsonic filter. A subsonic filter blocks ultra-low frequencies
that you can’t hear from getting to the subwoofer. This lets the sub operate more efficiently Zak: There’s a couple other important things
to look for in your filters. Some filters are variable. They let you select a frequency for the filter. Others are fixed, meaning that they limit
you to a specific frequency. Ken: Variable filters let you tailor the output
of your amplifier more precisely than you can with a fixed high- or low-pass filter. And there’s one other feature to look for:
a bass boost. Zak: Yeah, a bass boost augments the low frequency
output of the amp so you get a bigger bass output with your subs and your larger speakers. Ken: A bass boost frequency can be fixed or
variable and the amount of boost can be fixed or variable too. Zak: Kind of like the filters we talked about. Variable bass boosts give you some more choices
in how you tailor the sound that your amp puts out, so keep an eye out for this feature
if you’re planning to amp subs. Now besides the number of speaker output channels
we talked about earlier, amplifiers have other outputs and inputs that you may want to look
for. Ken: The first is speaker-level inputs. Most amps get their signal from the receiver
through RCA inputs, which are connected to your stereo’s preamp outputs. But factory stereos rarely have preamp outputs. So if you’re connecting your amp to a factory
radio, the amp will need speaker-level inputs like these. They’ll let you tap into your car’s speaker
wires for the signal your amp requires. Zak: If you’re going to put together a system
with multiple amps, you might want to think about an amp like this one. The reason is, it has preamp outputs, so you
can send a signal into the amp and then out again and into another amp without having
to run any extra cables all the way from the stereo. Ken: Another question we hear a lot is ‘Why
should I buy a more expensive amp? What am I getting for my money?’ Zak: Again, a good question. To answer it, we’re going to look under the
hood of two amps. One is a more entry level and affordable amp
and the other one costs a little bit more. So what are you getting for that money? Ken: Now these are both mono amps of similar
power built for driving subs. This one is an entry level amp that sold for
about $200. It’s a good amp, but right away you can see
a basic, generic circuit board with a lot of exposed metal traces and wires. That can let noise into the system. It’s got small FETs or Field Effect Transistors
underneath these small heat sinks. That can let them heat up and create distortion. The capacitors are small and the coil is small,
so you don’t have a lot of reserve energy for when you crank the volume. Zak: Now, over on this side, we have an amp
from Rockford Fosgate priced in the $300 range. On the inside, you can immediately see what
you’re getting for that extra money. You’ve got this high-quality custom-built
circuit board tying everything together. You’ve got larger, beefier components throughout,
and you’ve got this vented heat sink that goes all the way around the outside, and that’s
going to keep the amp running cool and much more efficiently. Overall, you’re getting a better built amp
which equals better performance and better sound. Ken: But we haven’t talked about one of the
most vital factors in amp performance: amp wiring. Zak: Your amp depends on a steady supply of
power to operate at its peak, and that’s why you should invest in a high quality amp wiring
kit when you buy the amp. Ken: If you use too thin or cheap wiring to
hook up your amp, you’re starving it of the power it needs to do its work. Zak: The bottom line is you’re not going to
get the performance that you paid for. Ken: To see all the amps we carry, go to,
and be sure to check out which wiring kits we recommend. Zak: To learn more about choosing the right
amplifier, go to Ken: And for personal, one-on-one help call