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How does more power improve sound quality?

7K views 68 replies 22 participants last post by  FoxPro5 
#1 ·
I've currently got a 5-channel Infinity amp, powering 4 Infinity Kappa speakers and a sub. I hate the Kappas in the fronts (too bright and harsh), so I'm considering new front speakers...

One thing I've noticed when researching on this sight is that many people are pumping a LOT more power into their speakers than I am (my amp is powering 60 watts @ 2 ohms into the Kappas)...

I'm guessing that the goal of increased power is not simply to go deaf, but that it somehow improves sound quality and makes better use of the speakers? Is this true?

Since my amp is only delivering 50w @ 4 ohms (60w @ 2 ohms) into each of the 4 cabin speaker channels, is that a real limiting factor regarding how good the speakers will sound?

One option I have is to ditch the rears, and bridge the front channels, therefore they would produce 120w x 2 @ 4 ohms (the amp is NOT rated to bridge @ 2 ohms, so I can't simply try it with my current speakers).

So... how does more power improve sound quality, and would I be better off ditching the rears and bridging the fronts?

Thanks!
 
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#2 ·
headroom?
 
#4 ·
that is until it hits mechanical or you hear that funny smell. :D
 
#7 ·
The thing I noticed most about running a decent amount of power is how effortless the speakers sound. Of course, that because running small amps, you're usually running them at or near their limits therefor they sound strained, even if they aren't actually distorting to the point that it's obvious.

It all depends on your speakers too. If you are running very efficient speakers (like factory speakers) you won't need as much power, but most decent drivers are not particularly efficient and therefore really need power to sound good.
 
#8 ·
More power allows you to get the most from your speakers without having to crank the gain (which causes a lot of problems, clipping, background noise, etc.)

It will also make your set-up a little more dynamic.
 
#10 ·
Headroom is having that reserve power beyond what you need. In other words, a small amp may get fairly loud, but the amp is near it's limit. A big amp will drive the speakers to the same level, plus have plenty of reserve power for loud transients that would otherwise distort with the small amp.
Great explanation. I like that:)
 
#13 ·
No, your gain position on the amps isn't really relevant, you use that to adjust your amps sensitivity to your head units output.

It's having more than enough power for every situation. I prefer to reach my speakers limits before the amplifiers limits...and that, is headroom.:)
 
#25 ·
well that`s not totally true but it is to a point, take for instance ppi art series amps are regulated, it will give the same amout of power @ 4ohms say 100 watts between 11-12 volts but as voltages is increased they will give a little more output anywhere up 23-35 more watts...the A-600s were rated @ 600 watts@ 4 ohms butppi also said that they would do alittle bit more than that I think it was around 663 watts @ 4 ohms.
 
#24 ·
Some of these guys are also running nice 8's and 9's up front that want 150W RMS or more.

If your fronts only want 75W RMS each, then an amp giving you 200W RMS each really isn't being fully utilized. But you could always upgrade your speakers later to something wanting more power without having to change the amp. :D
 
#28 ·
Define "headroom"

in this case I'd consider it to be that the a high power amp vs a lower power amp, the one with higher power naturally gives more dynamic range at the output level simply because the amplifier is capable of producing it without going into severe clipping. A 10db increase requires 10x the power, so if whatever music you're listening to is using an average of about a watt, just a 10db peak is going to require 10W, a 20db peak compared to reference is going to require 100W. Obviously on a CD 0db is as loud as the peaks are going to get, so if you set your amplifier gains correctly by using a 0db tone and configuring your "max" to be just under amplifier clipping, a lot of people see just how often they were overdriving the amp. Consider that your average speaker might be around 90db 1W/1M...power is crucial for an overall clean system.

Now, comparing VERY SHORT transients, an unregulated design offers a little bit more headroom because the power supplies operate at a lower frequency, thus require substantially larger capacitors compared to a regulated design, where pulse width modification operates at a much higher frequency and requires smaller low ESR filter capacitors. That's all the "headroom" either topology can offer.
 
#30 ·
Decibel scale isn't linear, it's logarithmic. A 10db increase requires 10x the power and produces roughly double the perceived volume.

Let's say you are producing 90db at 1 watt and want to produce 100db.

90db=1 watt
double that gets you:
93db=2 watts
doubling that gets:
96db=4 watts
doubling that gets:
99db=8 watts
and doubling that would get:
102db=16 watts.

So realistically, 10 watts gets you that 10 decibel increase. 10db=10x power increase.
 
#36 ·
The decibel scale is just a way of compressing a huge range of ratios into understandable numbers. If you were running 1 watt and you wanted to increase 40db, you'd need 10,000 watts. That's really where the decibel scale helps. If it were a linear scale the numbers would be outrageous.
 
#38 ·
Actually, I don't think the noise floor has any connection to power output. Sure there are some noisy low powered amps, but there are noisy high powered amps as well.

The noise floor might very well be a side effect of people running their amp gains too high when they have smaller amps, and that may give the impression that larger amps have less noise.:)
 
#39 ·
I just recently switched from driving my mids with 70 watts to 160 watts. There is clearly the ability to drive the speakers to a greater volume level, so it just keeps getting louder cleaner. But the 70 watts could get very loud. The best way I've heard headroom's effects described is that it allows louder sounds to play louder (of course, up to the inherent limitations of the drivers) before distorting. When you're sitting in a live acoustic performance for example, some instruments may surprise you with their volume or impact. Well, the more headroom you have the more lifelike or realistic those moments are and the cleaner those moments sound. So, the result is also more realism and detail especially in well-made recordings.

The past couple of days I've been listening to cd's that I haven't since I upgraded. And I'm hearing words clearly in the vocals that I couldn't quite understand before and hearing softer notes and instruments that I didn't notice before. :)

Try it, you'll like it. ;)
 
#40 ·
How much headroom would be used on a typical subwoofer? For instance, your sub is rated at 500W RMS.. do you go with an amp that will do about 500x1 or would you go with something 600+ x1?

I always thought of RMS ratings as were more of a thermal rating. So it seems like going over that thermal rating would be too risky.. no?
 
#45 ·
What's the avg efficiency of your typical class A/B at delivering power? How about 55%??

What the avg efficiency of your typical driver of converting mechanical energy to sound? How about 5-10%??

How loud is the music you typically listen to? If you listen to classical that's recorded at -20 dB, how much power do you need to satistify your particular desires? How dynamic is that music? If you have +/- 50 dB of dynamic range what does that mean for the fairly inefficient amp and horribly inefficient speakers playing it?

If you add more power, you are just playing with these averages. NO amp on the market does it's RMS power as you are led to believe. It's always changing as the music changes...through peaks and dips.

First rule of car audio: buy as much power as you can afford. In the end, it's a crappy investment, but you gotta do it!!
 
#49 ·
I would agree that "headroom" is more power than you typically need, and not necessarily more than the speaker is rated for. It all depends on your listening preferences. I also agree that a lot of power is more beneficial to the front stage than the sub woofer...assuming you don't blast rap to annoy your neighbors.

Now, should you skimp on the sub? Absolutely not. Get as much power as you can afford, that will fit in your vehicle and your electrical system can handle.:D

Personally, I listen to music quite loud sometimes so I like a decent amount of power.
 
#58 ·
I'd go as far as saying that corrects amounts of power is just right.

A bigger amp will have a higher noise floor.

But at the same time you want enought power to have the dynamic reserves when you need them.

If you have loads of money it is easier to find amplifers with lower noise floors and much power. If you're on a budget I've found that there is seldom much gained from having more power then the RMS rateing on the spekaers.
 
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