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how do i find the right amplifier for the sub i wanna get?
like say i wanna get two Alpine type-r subs
there are millions of amps out there and ive read that you need to match the power of the amp with the sub otherwise the life of the sub/amp becomes less significantly
how do i go about doing this?
When choosing amplifiers you can either rely on an experienced installer to listen to your needs and then recommend and amplifier to suit or you can look at them yourself.
There are a few specific amplifier specs you should look out for though because choosing an amplifier is about more than just watts. When speaking to anyone about achieving quality music in car audio most people simply focus on the speakers rather than the amplifier. They often speak about speaker build quality and power handling, enclosures, porting, fibrefill, loading and speaker cable. You don't really need to worry about the amplifier so long as it's powerful enough right? Just like when you're considering the purchase of a new car; the only thing you need to look at is the power output of the car alone right? Wrong.
When choosing an amplifier to power your speakers there are more stats than just power output you need to think about before you splash a couple of grand on an amp that will sound like rubbish. For those among you dreading an upcoming lecture on amplifier classes, resistors, capacitors, transistors, transformers and power supplies relax, I'll keep this to plain English for the explanation of which stats to look out for. High power output is important but quality amplifiers are not just about sheer power. Mining dump trucks have over 6000 horsepower but that doesn't make them spectacular performers. Besides power there are certain other important figures that must be taken into consideration when choosing a suitable amplifier. We'll go through a few of the more commonly found stats.
Damping Factor
Damping factor describes an amplifiers ability to control a woofer cone. It's the ratio of rated load impedance to the internal impedance of an amplifier. The higher the damping factor the more efficiently an amplifier can control unwanted movement of the speaker coil. High damping factor is crucial for subwoofers and the higher the damping factor the better. It is debatable if anything over 50 is audible. Damping factor is calculated by dividing the speaker impedance by the output impedance of the amplifier. In other words the damping factor will decrease as the speakers impedance decreases. This means an amp optimised at 4 ohms will provide tighter bass than when they're running at 2 ohms. A lower damping factor will leave bass notes sounding soft and undefined, regardless of the amplifiers power output. You can see by this that a smaller 100 watt amplifier with a high damping factor can often sound better than one twice it's size with a low damping factor.
Slew Rate
Sometimes referred to as damping factor for tweeters, the slew rate describes the amplifiers ability to accurately control fast direction changes of a speaker cone or dome. Have you even turned your stereo up to discover that your cymbals sound like someone throwing a brick through a glass window? That's because the amplifier simply wasn't fast enough to accurately reproduce the high frequency ring of the symbols. Measured in volts per microsecond, a low slew rate softens the definition of a sound signal which blurs transients and causes the sound to appear muddy. A high slew rate means the amp responses faster which ultimately results in crystal clear highs.
Total harmonic distortion
THD is the measurement of the how much the amplifier can distort the sound signal through the introduction of added harmonics or overtones. THD figures are usually given as percentages and a THD figure below 1% are generally inaudible to most people. However, distortion is a cumulative phenomenon so if your head unit, eq, crossover and amplifier are all rated at less than 1%THD each, together they could produce 5%THD which may well be noticeable to most of you.
Signal to noise ratio
Noise leaking into the sound signal is an ever present problem in car audio. The Signal to noise ratio is a measurement of noise level in the amplifier compared to the level of the signal. A higher S/N ratio signifies a greater difference which is better. Technically speaking, it's the ratio expressed in dB of signal power at a reference point in a circuit to the noise information that would exist if the signal were removed (the noise floor). The maximum signal to noise ratio of the amp can be seen as a measure of realistic fidelity. This ratio is how much absolute noise it produces compared to the highest signal voltage it can pass without distortion. Many companies combat noise by utilising balanced line systems.
Stereo separation.
Separation is not spoken about much but this refers to the amplifiers ability to maintain the separation between the right and left channels. This is essentially what allows an amplifier to reproduce an accurate sound stage. Each individual instrument is after all, are recorded in it's own location in the sound stage and you should be able to hear this in the same way when it's played in your car.
Just a final few points to remember while you're looking at specs. You'll find many are followed by the term 'A weighted'. Put very simply, 'A weighting' is a way of colouring the figures a little to make them appear more attractive. Loading is another issue to consider. Watch the impedance of speakers when choosing them because while most amps are stable at low impedance levels, they're not overly efficient nor performing 100% when loaded down. Your cars engine is 8000rpm stable but it's unwise to try and keep it there for long. By the same token many amps are 2 and 1 ohm stable but this is for intermittent spikes (as music is dynamic it causes the speakers resistance to continuously change during playback), not continous everyday running. These are some of the more important figures to observe when buying amplifiers. It's not simply just a matter of buying which ever amp outputs the most power. It's a matter of taking all the figures into consideration and choosing which amplifier best suits your needs.
The best amplifiers around for realistic prices are:
ARC Audio
Tru-Tech
Zapco
Phass
Boston
Diamond
Phoenix Gold
Vibe
U-Dimension
Brax
McIntosh
Audison
Plus there are many more.
Ahh yeah..... :confused:
Exactly what i was gonna say! :)
No, seriously i learnt something out of it! :thumbsup:
that's all well and good, and scientifically measurable, but is it really audiable (all things being equal (ie level matched as seen in richard clark's amp challange)? i know rc's amp challange get's used as an example all too often, but why not? it's been going for years and afaik no one has gone close.
imho you're better off buying an amp with the features you need/want (power output, adjustable filters, brand association (read record of reliability, and resale value), cosmetics etc. your money could be better spent on installation than on inaudiable differences.
This issue has been discussed at length in just about every audio group and usually ends up as an "I can hear the difference, you don't know what i hear so how can you say i'm not hearing a difference" Vs. "There is a measurable difference; but it's beyond the threshold of hearing".
champ Fhrx thanks heaps for that :)
That arguement too is debatable. I've heard many people here and in the US claim that RC is full of it and hasn't a clue about what he is talking about...Quote:
Originally Posted by micka
It's one of those never ending arguments. Many people claim the difference can be heard, many don't.
I tell you what though, when you turn your system up, you'll soon have a stunning demonstration of whether your amplifier is up to par to not. :(
I agree it is very debatable, hence the discussion at large in just about every audio scene. and the need to present both sides of the discussion unless you have difinative unchallangeable evidence. I'm not trying to change anyone's beliefs, they can believe whatever makes them happy; just trying to alert them to alternatives.Quote:
Originally Posted by Fhrx
"turn your system up?", that sounds suspiciously like a function of power:PQuote:
I tell you what though, when you turn your system up, you'll soon have a stunning demonstration of whether your amplifier is up to par to not. :(
"turn your system up?", that sounds suspiciously like a function of power:P[/QUOTE]
i think u will find he is refering to equaly powerful amps just different quality.
i also beleive there is a large diffference in quality of sound with amps
so what you're saying is if 2 amps are level matched (not just have the same power rating on the box, but genuinely level matched so actual power output is the same) then one will be louder than the other? I'd be very interested in the physics of thatQuote:
Originally Posted by urtwhistle
Not so much louder, it will be clearer.
For this argument lets just leave some real world figures at the door (yes I realise that as volume and music signal changes, so do the various statistics of amplifiers) but we could write a thesis on all the side tangents and I don't really wish to do that again.
Speaking purely subsonic frequencies, If you get two 100 watt amplifiers running at near full power, one with a damping factor of 20 and the other with a DF of 1000, the later amplifier will sound much clearer and could be perceived as louder to our ears as the volume goes higher before audible breakdown of the sound wave and eventual clipping occurs..
sorry, i was being facetious, it's a bit difficult to get accross on this non-verbal medium:(Quote:
Originally Posted by Fhrx
wouldnt all u need to choose the amp is to find out the rms power of ur subz.. and add dem.. finda a 2 channel amp.. which has the rms output power equal wid the subs or jus bit over..??
Sorry but could you please repeat that question again. In English perhaps? :p