Sound 101

[Crysalis]

So... you're lookin fer some bumpin speakers eh? Well, heres some tips for you. Headphones can also follow these guidelines!

First of all, wattage isn't everything. Wattage is only the power your feeding to it. Also, especially when looking at 5.1 or 7.1 systems, when the box says "A WHOPPING 100w!", you have to remember... that 100watts is divided 6 ways (5.1) or even 8 ways (7.1). Usually, the sub will get most of the power and the satellites will get a miniscule amount. Higher wattage is good, but not always better. As this is just basic information, I'm not going to get into RMS and Peak power ratings, but researching these two forms of power is DEFINITELY a must when looking at speakers/amps. Also, resistance (ohms) is another thing you may want to dabble into.

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Since wattage isn't everything, what is? Sensitivity!!! Ok... so you spent your hard earned cash on some awesome speakers with 500 watts of power. Freakin sweet eh? You open the box, get everything all set up and you go to press PLAY anxiously waiting for your heart to be resuscitated by the massive 500watts flowing through them speakers. You press play and what you hear is good. Then you take the dive and turn the volume up. "WTF?! I've got these things all the way up and they aren't loud whatsoever!! WHAT BS!!!" Sensitivity my good friend. So what is sensitivity? Well, in most specifications you will see a section called Signal to noise ratio (SNR) or sensitivity. Then you will get a number followed by dB (decibels). Say this number is 50dB (which is horrendous), that means for every one watt of power going in, 50 decibels of sound will come out (if playing white noise at nominal level). Most consumer quality stuff ranges from 70-80's. You really want at least 89dB. Anything above 90 will give you plenty of volume and will use its wattage more efficiently.

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Anything else? DUH! We haven't even scratched the surface! Frequency range!! Frequency range is that weird section of numbers that no one ever understands. (100-20,000hz). What the heck does that mean? Well, hz (hertz) is a measurement of how many times a sound wave cycles in one second. So, the lower the number, the slower the wave. Thusly, the slower the wave, the lower it sounds. The human hearing range is technically 20hz-20,000hz (or 20khz). I consider the USABLE range to be 30hz-18khz Although I can hear 20-20k, people above 25 years old(ranges) can't hear much above 17k due to hearing damage (no matter what you do, it happens when you get older).

A GOOD frequency range is having the first number as low as possible and the second number as high as possible. So, if your speakers have a 75hz-16,000hz (which is not so great) range, if you play anything below or above those numbers, you wont hear it as your speakers can't play it. Chest thumping is normally found around 30-60hz. A good range I like to follow is to keep the first number below 50hz and the high number at least at 18khz (or 18,000hz).

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Digital versus analog! WHAT?! THERE ARE NO SUCH THINGS AS DIGITAL SPEAKERS! NEVER! Speakers are purely an analog mechanism. A speaker consists of a magnet, a voice coil, a spider and a cone (with a dust cap in the middle, which really serves no purpose). Essentially, the speaker vibrates (in AND out) to move molecules which form sound waves. When a description says DIGITAL SPEAKERS, that means it has a digital to analog converter (AD/DA) OR it has a digital decoder built in. Digital connections only transmit information. No audio whatsoever. Just a bunch of ones and zeros.

So now you should have a basic understanding about speakers and headphones. Now, go out and get yourself some GOOD speakers (excluding Bose).

Whats next? Wiring!

Let's say you've got some sweet speakers and a really sweet amp. Rock on eh? Car install, home theater, whatever... wiring it all up goes here! There are a few different ways to wire things up, but first we gotta understand the basics:

• Ohms (impedence or resistance)
• Wattage
• Load
• Phase

Let's start with resistance! This can be quite the challenge, but its quite simple. Every speaker has a level of resistance, called impedence. Impedence is measured in what's called Ohm's. Now, we could get crazy and go into Ohm's Law, but theres really no point without going into some advanced stuff. Just so you can see it, here is the Ohm's Law chart:

This is used for figuring Impedence (resistance), wattage, voltage, and current. Simple math as long as you know the information. Anyways, back to resistance. You know how on your amplifier it says it can handle X amount of ohms? Well, thats what is called Load. 8ohms and 4ohms are the most common, but there are components that run even lower than that. How do we figure out load? Well, that all depends on how things are wired up. There are three ways to wire: Series, Parallel, and Series Parallel (I know, scary... don't worry). When hooking up more than one speaker, you have to use one of these wiring methods. Though it may seem obvious, but "black goes to black and red goes to red". These are the positive and negative leads. This gets into phase, which we'll learn a bit later.

Series:

As you can see, there are two 8ohm speakers hooked up. When you wire them in series method, you add the resistance of all of the speakers, and you get your load. In this case, 8+8= 16ohm load. REMEMBER! The higher the resistance, the lower the output. Why? Most amplifiers can handle high loads. The less resistance there is, the more power the speakers will draw from the amp, the more output (and we all know what that means... LOUDER!). The smaller load rating on the amp, the better. If the amp can handle 2 ohms, you better be sure it can give you more than enough power for any application. In the case of the picture above, it won't be very hard at all for the amp to drive those two speakers, but keep in mind that it sure isn't going to get that loud. It may be better to wire it in a different method, such as parallel!


Parallel:

Here we have the same to speakers, but wired differently. When wiring in parallel, you multiply the resistance of all of the speakers, and divide it by the sum of all the resistance of the speakers. This will give you your load rating. Here we have two 8ohm speakers wired in parallel. So, we take 8 * 8 = 64 ---- 64 / 16 = 4 ---- This gives us a load of 4ohms. If we were to hook up this to the same amplifier as we did with series, we would get a much high output since it is drawing much more power from the amp.

Series Parallel

....MORE TO COME LATER....

 

[veedubfreak]

Dont forget that 500W from 1 manufacturer is by no means comparable to 500w from another manufacturer. Every company measures their equipment differently.

 

[Drizzt]

This also goes for headsets right?

bookmarked for the next time i buy a headset if so.

 

[Oreo]

Great guide. Include some more on headphones, if possible, like open-back closed back, semi open etc etc.

 

[EricB]

Dont forget that 500W from 1 manufacturer is by no means comparable to 500w from another manufacturer. Every company measures their equipment differently.

Great guide crysalis. somebody finally get it start. I know that I was BSing about it

veedubfreak, I will touch more on this in the next few days. I Guess some people do want our input.

 

[ncjimn]

Now, go out and get yourself some GOOD speakers (excluding Bose).

hahaha

love that

 

[EricB]

this from another old posts. if you want to argue, don't bother to post. this is to inform people what to learn good sound.

what makes a good sub?

I know that you are interested in good sound because you asked instead just going out and buying one.that's the big mistake that most people make

A good sub should

1. go deep
2. be relatively flat down to 25 hertz.
3. have a box qtc of .5 to .7
4. have a group delay of leess then 5 millesecond

somebody here once said that everything sounded the same and any differences in sound were in your head. Bull Ship.


what you get when you buy subs today.

1.a boomy, resonant sound. this is an inaccurate sound. but since it's so cheap to do as you just build a box and stick a speaker into it, they why you see these everywhere. the fact that so many americans like this makes matter worse. A 40 hz pure tone should not sound like a cannon going off

2. a box qtc of 1.0 to 1.5. I will post graphs later to explain what this means

3. group delay up 50 milliseconds. this will drag and distort a pure tune.

4.boxes made out of all things these days, plastic, glass and plexiglass. everybody know that you need materials that's dead to sound (mdf, birchwood, etc), not BS that adds to and colors the sound

american sucks at listening to music. they always had but since 2000 everything got worse. the music, the economy and the manufactures. the new trick is too make BS and over market it. it obviously works because joe's off the street now claim to have "golden ears"

will finish later

P.S. BOSE will never ever sound great. a lot of people swear by them. they don't know any better. the marketers got to them

 

[EricB]

Bose don't care about accurate sound. They use psychoacoustic special effects and boom to wow people who know little about sound.

Here is a qtc graph. A box with a qtc of 1.5 will boom with little power. It will be loud. That's all most Americans care about. It won't be accurate, it won't play deep and it will sound nothing like the original note that it's trying to reproduce.

A box with a qtc of .5 has lots of drawbacks. For one it is inefficient, meaning that you will need a lot of power to power it. The bass will be a little weak compared to an enclosure with a higher Qtc to a person who knows little about sound. It also requires a large box.

However this is the most accurate, purist and deepest bass. The general rule to bass is "the bigger the box, the better the bass". Whenever, you go to true audiophile's house, you will notice his humongous box and gigantic amp for his sub. Then when you hear it, you will realize that never heard bass so amazing and heartwarming. This is the leanest sounding bass (pure).

Nobody will design this kind of sub box and sell it, because it just isn't feasible to market it. Most people will prefer the little inaccurate box in the corner. Audiophiles will build their own home subwoofer box or pay somebody to do it

The best companies will compromise for a box qtc of .0707. This require a nice size but not too large of a box and a moderate size amp. This gives you the flattest response too. They will usually add equalization to the speaker if the box is sealed. This is the most practical way to get 20 hertz in a house setup

The better companies will settle for a box qtc of 1. They will give a little boom and a little accuracy in a little box and a decent amp.

But most will go for the qtc of 1.5. No accuracy, lot of booms very little power. you have to spend money to get truly accurate bass. that's how speaker work really. the more you spend the better the sound that you get.

They will also put these speakers in a square box (a taboo to box builders) to give them even more boom because a square box enhances standing waves

Here's a nice place for subs


Subwoofers Reviews at AudioReview.com

 

[Fat.Clown]

Bose don't care about accurate sound. They use psychoacoustic special effects and boom to wow people who know little about sound.

what are your views on the Bose AE headphones?
while it may not have the greatest sound
comfort takes priority over sound quality in my case
and those AE sure are comfortable...

 

[Oreo]

There are alot more comfy phones than bose, Senn, AT, AKG, etc