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Rewdoalb

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Joined
Feb 2, 2008
Messages
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Hi everyone,
I've been trying to figure out more about computer audio. For all my short life, this has consisted of two crummy speakers plugged right into the motherboard.
As I peruse the forums, there are so many terms and components that I'm drowning in them.

Are there any good resources that explain how all this stuff works? I understand what speakers and subs are but that's about it, I see you guys talking about DAC's and receivers and such - just trying to understand what this stuff is, how it's all connected, how much of it you'd have in a $250 setup vs a $500 setup vs a $2000 setup. Since there isn't a FAQ section or anything, any links to sites or good threads in here that could help?

Thanks :D

Rewdoalb
 
If you are trying to understand it all, don't lose sleep over it, because you won't. Nobody does.
One thing is for sure, that even if you read a entire book about it, you probably won't know the difference. Sound is not something you learn to appreciate with text, but with experience. I know this, because I know people that can listen to music from their TV speakers, and then listen to music from good tower speakers, and they honestly can't tell the difference. Are they deaf? NO. They just either don't appreciate sound, don't understand it, or simply don't care.

As for websites to read on, I actually don't have any in mind. I came to this forum a few months ago with no idea what a subwoofer really was, let alone receivers existed. But after some research on my own and reading tons of posts here, now I feel a lot more confident. I'll try my best to give you a general overview, so here I go.

Ok, so you mentioned something about DACs, and it stands for Digital-to-Analog Converter. The opposite also exist, called ADCs . Those two are used to convert a signal, sound in this case, back and forth between the digital world of computers and the analog world we live in. So yes, everything originates in analog at some point, and then an ADC turns it into digital so we can store it, and controll it. When you turn something into digital, it needs to be converted into a "language" or "flavor", so a computer can understand it. We call it a Codec, and that process is called Encoding. So to do the reverse of that, is to Decode it. Mp3, Wma, AAC, AC-3 are examples of Codecs.

However, after the modified sound is turned into music in a computer, we need to have a way to share it with others in the real world, and that's where DACs come in. Those convert the digital representation of sound that is in 1's and 0's, and converts it into something we understand. However, that is not enough. We need a medium in order to communicate, and that's where speakers come in. But speakers don't work by magic, they need power to amplify that signal. There are standalone Amplifiers which only do that, but there are also Receiver which add extra features. Receivers normally come with an large amount of connectors, so you can connect different devices to it, effectively saving you money and space. They might also come with Decoders, so they can convert different flavors of digital signals into analog themselves, resulting in higher quality in some occasions. There are also things called Processors. They are more advanced, and with upgradable features. Consider them as a hybrid between a Computer and Receiver.

So after we have the signal amplified, we can then feed that into a speaker. In simple terms, they vibrate air. The movement of air we call it a Wave of sound. But sound doesn't travel as a whole, it gets divided in Frequencies(measured in Hertz or Hz), just so it can describe itself. Think of it like McDonald's, where you need to order fries, a soda, and a BicMac, before you can call it a ValueMeal or a #1. Those frequencies are the parts, the ValueMeal is the sound. Those reaches your ear, which has TONS of little hairs deep inside. Those hairs are designed to interpret those frequencies and turn it into brain language, and then your brain turns that into the sound you perceive.

Since all speakers are not capable of representing all frequencies accurately, that's why we have different types. Subwoofers produce the lower ones, or what we call Bass. The Woofers produce the Mid-Range, while the Tweeters produce the Highs.

OK, so that is the general idea. If you need more info into something specific, just tell me, and I'll try my best to explain it in simple terms. Once again, I don't understand everything, so I just try my best. Just know that this is just the tip of the the iceberg, all the process that goes into sound is WAY more complex than I can ever understand.
 
Excellent explanation. Also, if it wasn't clear, analog = information via electrical properties (in the case of audio), basically. Frequencies, voltage, etc. Digital is the language of machines and analog is the language of tangibles. For audio components, the tangibles would be electricity and sound. Therefore, we need a device that translates back and forth between music files that are encoded in the language of machines and speakers that can then produce the sound through an understandable medium (air) for us.

http://en.wikipedia.org/wiki/Analog_signal
 
The funny part is that a $250 system often means $250 spent on speakers while a $2000 system often means closer to only ~$1000 spent on speakers while the rest goes to improving other components.

Of course even for a $250 system, you can prioritize upgradability or try to get a subwoofer in and still only spend around half your budget on the actual satellites.
 
Great explanation indeed. Sure makes it easier to grasp. Just want to say thanks for taking your time to write such post and share what you know with everyone.
 
I'm in the same boat as the OP. I own a set of Z680 speakers, but I never really thought about getting anything besides computer speakers for my PC. Well I was wondering how buying my own satalites and subwoofer would compare to a Z5500 or Z680 setup?


I'm thinking the most important part of the setup will be speaker placement. I see many speakers setups in the sticky, but they have the center way to close and the side speakers on the desk which in my opinion are way to close. I was wondering if you pull the desk away from the wall and mount the speakers on mini speakers stands to get a evenly spaced 5.1 surround setup??

Anyone want to give their opinion on this?
 
eddie500 said:
I'm in the same boat as the OP. I own a set of Z680 speakers, but I never really thought about getting anything besides computer speakers for my PC. Well I was wondering how buying my own satalites and subwoofer would compare to a Z5500 or Z680 setup?


I'm thinking the most important part of the setup will be speaker placement. I see many speakers setups in the sticky, but they have the center way to close and the side speakers on the desk which in my opinion are way to close. I was wondering if you pull the desk away from the wall and mount the speakers on mini speakers stands to get a evenly spaced 5.1 surround setup??

Anyone want to give their opinion on this?
Click to expand...

That's generally the ideal. You want to be roughly in the center of the room for a surround setup. Speakers on desk only really works for 2.0/2.1 setups.

Otherwise the 3 fronts will be way too close together.

Speaker placement is important, but getting good speakers is fairly important too. You want your speakers to be able to accurately handle vocals, which cheapo ones (computer speakers) generally do a poor job, at most being passable. Generally, you need speakers with 4 or 5" midwoofers minimum if you want good vocals.
 
Computer speakers are generally just cheapo. The enclosure is made of plastic. It vibrates. Just by design, it's cheapo. Also the amp is sadly not that good. Also, I believe the tweeters blow. The only thing decent are the mid-sized woofers.
 
YelloFelloJP said:
I have Klipsch ProMedia 2.1's. Are they considered cheapo?

Not being sarcastic, I'm really curious.
Click to expand...

I would say so. An inexpensive set of passive bookshelves can easily cost $150. The real question is, are you satisfied with them? I am not talking about how true they are to the source, how loud they are, what is the frequency range, etc. Not to call you dumb, childish or anything, but I can show a child a broom and dustpan and they may be thrilled for a long time, so why would I buy them a Playskool <insert expensive toy name here>? With audio and videophile equipment, sometimes ignorance(which is not stupidity) is bliss. For my needs though, I'd call them crap.

Relative to the rest of the thread:

For any Audio/Video questions and learning, AVSForum.

It seems this topic's discussion was well started by Odin75, so I don't feel the need to condescend and repeat. Quality explanation sir/miss.

A $2000 setup can vary greatly from person to person. Say all they do is listen to stereo audio recordings; they may have 2 sweet tower speakers and a stereo amplifier with a media transport device feeding it(say a CD player). Someone may be into surround sound movies, that other guys setup is far from their ideal.

I listen to Stereo and Quadraphonic audio recordings primarily, hence the setup in my sig and that I do not have a surround setup. I would enjoy adding say a set of C-500s and a C-C100 and maybe a nice Mirage sub to my PC rig for 5.1, but I feel the gain would not be at level with the costs incurred at this time(after next car purchase).
 
If I wanted to use my own speakers, what would I use for an external amp? Assumeing I am using a X-FI sound card, what would I need other than the speakers? I need an amp, would I need a processor also?
 
Depends on the speakers and depends on what you're comfortable with. You could get an integrated amp (preamp + amp in one box), receiver (processor, amp, preamp in one box) or you could get them all separate. The minimum you would need is an amp. I ran my speakers by plugging my amp directly into my onboard audio for a while. It ran quite alright (except for shitty DAC quality ofc).

And that's only if you have passive speakers. With active speakers, nothing extra is required.
 
eddie500 said:
If I wanted to use my own speakers, what would I use for an external amp? Assumeing I am using a X-FI sound card, what would I need other than the speakers? I need an amp, would I need a processor also?
Click to expand...
Yes, like Alai said, it really depends on the speakers, but let me clarify a little bit more. Speakers normally come in 2 major categories. Passive and Powered:
Passive speakers are the ones that need an external source of power for them to work, an amplifier. In your example, this amplifier goes connected between the X-Fi and the actual speakers. This kind of speaker is often found in Home Theater setups, mainly because you can pick the amplifier of your choice, there is more speaker selection, and also tend to be cheaper (for obvious reasons)
Powered speakers in the other hand have the amplifier inside it. This type you can easily be connected directly to the source device, the X-Fi or even a dvd player. This type of speakers are normally found on computer type speakers, or Monitors. When I say Monitor, I don't refer to screens, but a style of speaker. Monitors are designed with the purpose of producing very realistic sound and trying to make the frequencies as flat (balanced) as possible, at the cost of other things like Watts and frequency range.

What is recommended?
Normally when you wish to use 2 speakers only (2.0), you might have a better deal if you pick powered speakers. This normally bring an amplifier and speakers very capable of producing good sound for small rooms. If you want to go the extra step and add the subwoofer (2.1 now), is also recommended to buy a powered one. Subwoofers require a lot more power than regular speakers, so if it doesnt' have its own amplifier, you might have to buy an external one, making the cost higher in sometimes. For 2.1, some vendors offer a package in which they have a powered subwoofer, and 2 passive speakers which you connect to the back of the actual subwoofer.

For 5.1 and 7.1 setups, things change a bit. To be more cost effective, is a good idea to buy all the regular speakers Passive, and then buy an external amplifier to power them. Receivers are a great type of amplifier, because they give you extra connectors and features that you might need, giving you the most bang for your buck. As for the subwoofer, a powered one still is the best choice.

So there you have it, that is my advice, and what most people advice depending on the preferred setup. Remember, this is often the cost effective way of doing it, but there can definitely be other options available.

PS: No, you don't need a processor. Nobody needs one. Unless you have an extremely expensive and complex system, and you know exactly what to do with it.
 
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YelloFelloJP said:
I have Klipsch ProMedia 2.1's. Are they considered cheapo? Not being sarcastic, I'm really curious.
Click to expand...

Warning: once you start listening to something better it's hard to go back... And your wallet will suffer. :D It probably sounds snobbish to 90% of the ProMedia/Z-5500/Z680 users out there, but listening to music or even gaming on that type of speaker is akin to gaming on an old 17" CRT to me, maybe a 1280x1024 19" CRT if you don't wanna be so harsh. :p Some people spend $300+ on a video card, $500 on a large display, $200 on a processor, etc, and then they completely ignore audio or they get suckered into something w/o doing anywhere near as much research into it as all their other purchases.

Some of the best resources for info (particularly when it comes to specific purchases) have already been linked above so I won't rehash that. There's fairly affordable alternatives (that might even cost less than what you paid for those computer speakers) that will introduce you to a whole different world though.

Then there's headphones... :eek:
 
Hey, don't knock CRTs. I don't use it for my main display, but they still work fine. They're also free if you're patient, I get 2-3 a year in great condition because someone abandoned it when they got an LCD with their new Dell. Got 2x 21" Trinitron now and so many 19" and 17" CRTs that I don't even bother to pick them up anymore unless they're unusually good.
 
I still have a 19" CRT (it's my second display, see sig~), in many ways it's better than some LCDs... Certainly easier to watch TV on it from the bed than it is to watch TV on my TN LCD. :( I was just trying to provide a good analogy, maybe stating that it's akin to gaming at 1024x768 or 1280x1024 w/no AA rather than mentioning CRTs would've been more accurate. ;) Or maybe gaming with a ball mouse! But I'm sure someone out there has a good reason why those still rock as well. :p
 
Thanks to everyone who contributed, I've started cracking down pretty fast on this learning curve ;)

Some quick things to clarify.

So a pretty basic/cheap, yet effective setup could look something like this: Computer with sound card, feeding into 2 powered speakers or a powered sub + 2 passive speakers.
I'm guessing this is a likely setup for someone looking to spend $250-$400 and already has the desktop built.

If this was the configuration, does the sound card serve as your DAC? Does it also function as a audio processor? And I assume that it doesn't amplify, so that if you wanted 2 passive speakers plugged into the sound card you would need an amplifier between them. If you DON'T have a sound card, as I currently don't, does the onboard audio serve as DAC? probably not audio processor though right, as it goes right to the CPU?

Let me know if this is on track at all haha.
 
All speakers (and headphones) require amplification. This includes satellites, subwoofers, whatever. The reason for this is that the DAC chip operates within a specific voltage range and can supply X amount of current reasonably...neither of which is likely to be nearly enough to drive anything. Sound cards incorporate minimal amplification, which can be enough to drive low-end headphones. This is a similar output level as an external DAC would provide, or other sources like say the audio outputs of a DVD player or cable box. This level of amplification is sometimes referred to as "line level" output.

Powered speakers (satellites and subwoofers) incorporate an internal amplifier, allowing them to be fed directly from a line-level signal. Passive speakers (again of all sorts) do not incorporate an internal amplifier, and are not (with very few exceptions) sensitive enough to be driven by a line-level signal, so passive speakers require an amplifier capable of providing more power. Likewise, headphones may require amplification beyond line-level, with different requirements depending on the specific model (e.g. high-impedance headphones need more power & voltage, very low impedance may require more power & current, and electrostatics require speaker-level power & quite high voltage).

Here is how this applies to the builds you outlined:

Computer with sound card, feeding into 2 powered speakers
Click to expand...

This works fine. The computer provides a digital audio signal. The sound card converts that into an analog signal (DAC stage) and amplifies it to line level. The powered speakers have an internal amp which amplifies it further, which they then output as sound.

Computer with sound card, feeding into a powered sub + 2 passive speakers.
Click to expand...

This would be problematic. The powered sub would work as the powered speakers above and would do just fine. However the passive speakers would only have a line-level signal to go off of, and the result would likely be inaudible. You need an amplifier capable of driving the passive speakers to complete this configuration.

Onboard audio functions exactly the same as a sound card, however it is subject to more design constraints in the form of limited space for the circuit, limited power availability, increased noise, and closer integration into the remaining motherboard circuitry. From a user perspective, an onboard solution is identical to a sound card, but it will often be of lower quality.
 
You can combine a powered sub with a set of active speakers, if you wanted to use passive speakers you'd have to add a reciver or amp as well. Active speakers generally have an amp inside one of the two speakers, the second one is technically a passive speaker, it's just being powered by that amp in the first one. But yea, basically the sound card is your DAC in any of those configs, ditto for on-board audio.

Audio processor seems like such a broad term... Maybe it means something more concrete to those better versed in high-end audio than me, but as far as I know there's thousands of different things that can fall under audio processing. EAX/OpenAL calls used in games would fall under audio processing as far as I know (something a sound card or on-board audio usually does, and external DACs don't since they aren't aimed at gamers). Dolby Digital for surround sound is another form of audio processing, etc.
 
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Rewdoalb said:
Thanks to everyone who contributed, I've started cracking down pretty fast on this learning curve ;)

Some quick things to clarify.

So a pretty basic/cheap, yet effective setup could look something like this: Computer with sound card, feeding into 2 powered speakers or a powered sub + 2 passive speakers.
I'm guessing this is a likely setup for someone looking to spend $250-$400 and already has the desktop built.

If this was the configuration, does the sound card serve as your DAC? Does it also function as a audio processor? And I assume that it doesn't amplify, so that if you wanted 2 passive speakers plugged into the sound card you would need an amplifier between them. If you DON'T have a sound card, as I currently don't, does the onboard audio serve as DAC? probably not audio processor though right, as it goes right to the CPU?

Let me know if this is on track at all haha.
Click to expand...

Yes to all your questions except the last one. Onboard audio is just an integrated soundcard like an integrated graphics card.
 
Rewdoalb said:
...Computer with sound card, feeding into 2 powered speakers or a powered sub + 2 passive speakers.
I'm guessing this is a likely setup for someone looking to spend $250-$400 and already has the desktop built.
Click to expand...
Sound card + 2 powered speakers = works fine.
Second option, depends. If you go back to my explanation, I said that for 2.1 setups is best to buy one as a complete package. Why? Because not all subwoofers are equal. So to make sure you have all the stuff you need, they offer things like the Klipsch ProMedia 2.1, where you plug passive speakers on the back of the actual subwoofer. In this case, you would connect a cable from the "Front" ( =front left & right) in your soundcard, into a controller in this speaker setup. This controller is sometimes attached to one of the speakers, or a separate dongle.

Don't get me wrong, there are subwoofers that allow you to connect a cable directly from your sound card. But to make sure you don't stress yourself over which ones offer this connectors, or any other problems you might encounter, that's why they make combos like that.
And no, you don't have to waste that much. ~$150 is the average for a decent 2.1 or 2.0 setup.

Rewdoalb said:
...does the sound card serve as your DAC? Does it also function as a audio processor?......If you DON'T have a sound card, as I currently don't, does the onboard audio serve as DAC? probably not audio processor though right, as it goes right to the CPU?
Click to expand...
Both the Soundcard and the Onboard Audio in your motherboard have a DAC inside. Whichever you connect the cable to, that will be the one doing the conversions. But, like Ashmedai said before, dedicated soundcards tend to offer better results than onboard sound.

Now, when you mention Processor, I think you are still confused, so let me clarify. There are 3 types of processors, but none of them have to do anything with each other:

CPU: This is a type of processor, and it's stands for Central Processing Unit. This is the one in charge of making your computer think and make calculations. However, this has nothing to do with audio. This is just there to make everything work, and is found in almost all electronics, not only computers. PS3s, digital cameras, and even calculators have one.

A/V Processor: This is a Audio and Video Processor. Consider it as an upgrade to a regular Receiver, just like a PS3 is an upgrade to a PS2. All it does is add extra features, like more complex video upscaling or more realistic audio upmixing technologies. Some of them even have the ability to upgrade their software, or add new one, without having to buy new equipment.

And before you ask:
Upmixing is when you have Stereo sound, like you would find on a YouTube video, and try to play it from 5.1 speaker setup. "Pro Logic IIx" is a type of upmixing technology, in which it tries to convert 2.0/5.1 signals to 5.1/7.1 in a realistic way, by trying to place sounds in their corresponding speaker (dialog in the center, ambient sound in the back, etc).

DSP: This stands for Digital Signal Processing. This generally stands for all alteration or modifications sound is going to receiver before being converted to analog. Upmixing, Pro Logic IIx, Bass Management, Equalization, Audyssey, and EAX are examples of DSP, because they alter the sound. Also, if your soundcard or video player offers any sound enhancing capabilities, that will fall under that as well.

To the contrary to some, I DON'T consider Dolby Digital part of DSP, but a Codec on itself. Sure, the mixing studio has to add DSP while they are working on it, but at the moment they Encode it into Dolby Digital and burn it into a DVD, it simply becomes a Codec. However, Dolby Headphone and Dolby Pro Logic are indeed part of DSP, and shall not be confused.

Also, some will claim that DPS is anything that is interacting with the sound, even if it's not been modified. I will agree to some degree, however, that is exaggeration. Might as well call Windows a DPS according to them.

ashmedai said:
...This would be problematic. The powered sub would work as the powered speakers above and would do just fine. However the passive speakers would only have a line-level signal to go off of, and the result would likely be inaudible. You need an amplifier capable of driving the passive speakers to complete this configuration...
Click to expand...
Well, except if the subwoofer have the required connectors to plug passive speakers right on the back. Like I said above, the ProMedia 2.1 are a great example of what I was talking about. I totally understand what you are trying to say here, and I agree 100%, but maybe I didn't explain myself clearly before regarding 2.1 setups.
 
Odin75 said:
Well, except if the subwoofer have the required connectors to plug passive speakers right on the back.
Click to expand...

I'm relatively sure those are for pass-through and do not themselves provide amplification. You would need to use the powered inputs and connect them to an amp in order for the outputs to do anything.
 
ashmedai said:
I'm relatively sure those are for pass-through and do not themselves provide amplification. You would need to use the powered inputs and connect them to an amp in order for the outputs to do anything.
Click to expand...
Yes, this is exactly what I mean. The white and red RCA type of connector is the pass-through, while the black and red clips are the speaker ones. That is what I'm trying to say.
 
I applaud you OP (and others) for seeking this knowledge and not just buying into the marketing hype of companies toting the "ultimate gaming speakers".

This thread is going to drain your bank account, mind you. ;)
Posted via [H] Mobile Device
 
Excellent thread. I'm stickying it in my subscriptions ^___^
I still have much to learn as well.
 
criccio said:
Also, the post Zenshi linked to in post #6 is a MUST read.
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Arkangyl said:
Intro
For those of you new to this thread: Hello! I'm Arkangyl, I'm a Computer Engineer (which means I know Electrical Engineering too) and I've done quite a bit of reading & research into computer audio. This thread is meant to be an introduction into computer audio for all.

For those of you following update: I've tweaked the format to make it more readable, I hope I didn't cut out too much of my original sass & literary prose in process :-P

Part I: Sound & Speaker Basics
A basic primer in how audio works is probably the best place to start this whole thing since without a good basis of understanding it will be hard to explain the higher level concepts. First, we'll do this with bullets:
- Sound is air moving at a given frequency (general range: 0 to 25,000+ Hz).
- You process sound by your brain interperting how your eardrum vibrates.
- Loudspeakers (what we call speakers, same thing) make sound by using magnets to move some material (aluminum, paper, synthetic) which in turn moves the air thus creating a 'sound'

Now to break things down further, there are three basic types of loudspeakers: sub-woofers, woofers / drivers, and tweeters.
Tweeters are responsible for frequencies ranging from [typically] 2 kHz to 20 kHz(good tweeters will hit 24 kHz, the uber ones can break into the 30 kHz range). They are generally 1/4" to 1" in size and come in quite a few different variants, wikipedia (tweeters) covers the different types pretty well. All tweeters have the same general design and goal though: to move very, very quickly to create the 'high' notes typically this is done with a cone (1/4 to 3/4" woofer optimized for high frequencies) or a dome ('dome' of material over the magnet).

Woofers handle the lower frequencies, generally from 55 Hz up to 2 kHz. They overlap in coverage with the subwoofer but their purpose is to create location & display the sound. Typical woofers range from 3 to 5 1/4" in size and are made from modern polymers (rubber-like substances), paper and Kevlar are also somewhat common. These low & mid range frequencies generally require a larger size (5.25" is a good size) to move enough air to push them out.

Subwoofers deal with the low frequencies, generally you'll see 30 - 150 Hz , and are 8-15" in size. Subwoofers are just larger woofers with a lower range, they operate relatively slowly and move a lot of air so you feel the sound. A good subwoofer will recover quickly from its last sound thus allowing each note to be a distinct sound, bad subwoofers can't respond that quickly and will mush notes together and muddy the music.

Here's a good illustration of how a speaker works (re-hosted from Wikipedia's loudspeaker / woofer / subwoofer page, re-posted under GNU Free Documentation License)
581pxspeakercrosssectio.png


Crossovers (lowpass / highpass filters) are also important to understand, when your computer sends out its audio signal, that signal (all cables coming out of the soundcard) have ALL the frequencies on them. Your various speakers, as mentioned, are each focused on a seperate range and will pretty much output crap if you don't specify what range should reach them. That's where a Crossover comes in, they are basic circuits that filter out the unwanted frequencies. There will be a crossover in the speaker between the inputs and woofer & tweeter AND one going into the subwoofer. All speakers have an ideal operational range, crossovers should be designed based around speaker specifications.
The general design is: voltage_in -> resistor -> voltage_out AND capacitor to ground.
The equation is cutoff_frequency = 1 / (2 * pi * R * C)
Crossovers (filters) can be built in combination with amplifiers too in order to boost the 'good' frequencies at the same time as you cut off the 'bad' ones.

The Box, the actual box the speaker is encased in seems to be overlooked by newbies and obsessed over by DIYers. Good speakers and commonly made with 3/4" MDF, glued at every seam (no nails or screws). The goal of a box is to NOT make any noise while the speaker is doing its thing. The box should not vibrate and the airpath (air comes in through a 'baffle' or that hole in your speaker :)) should be clear as if the air makes a lot of noise rustling around the box to get to the woofer / tweeter, you can hear it!

Soundstage, this is a fancy term referring to what everything sounds like when you're sitting there listening to your speakers. In short, a good 2.0 / 2.1 setup will create a better soundstage than a bad 5.1 setup. This means that 2 speakers will sound more like surround sound than 5 speakers will. There's a lot of fancy science here, but in short it has to do with accurately re-creating the sounds & how they're projected into a room. Much like a good ventriloquist can make it appear that people on the other side of the room are talking, a good 2.0 setup can make it seem like the sound is all around you

Specifications, I think speakers are about the only thing people around here buy without fully understanding the specifications. Most people look at power, inputs, and the stickers, and that's about it, but there is oh so much more to consider!
THD (total harmonic distortion), is a measure of distortion of the harmonic frequencies (harmonics are multiples of the fundamental frequency), these distortions are generally rather low (according to specs, all Swan & Onkyo systems are 1% or lower, Logitech is at 10% though!) and not perceived by the human ear (for most of us, the difference between 1% and .8% isn't worth paying for)
SNR (signal to noise ratio), is signal strength relative to background noise (SNR = 20*[log base 10](V signal / V noise)), the high the SNR the better, however know that 40 dB is VERY good and around 80 dB will be enough for most people as we're talking about very minor levels of distorion (Swan says they're north of 80 dB, Logitech says 93.5 dB, Onkyo says 100 dB)
RMS power, ahh, RMS versus peak power. The short & sweet explanation is that RMS is the power the systems going to be capable of, and peak is a sort of one-time maximum. RMS is what you care about. (Logitech = 505w, Swan M10 = 40w, Onkyo = 700w). Also look at watts per channel rather than just overall system power to compare 5.1 to 2.1 and 2.0.


Part II: The Digital Birth (audio files)
As I'm sure you've discerned from part 1, sound is an analog electrical ciruit. You're comput is a digital beast, and that's how you're music starts the grand process journey from your hard drive to your ears. There are many, many different formats to store your music in. To be honest I'm only familiar with a few, so if I miss any: post about them, share your knowledge too!

mp3 according to the RIAA the mp3 is the bane of the music industry (NO soapboxes about this stuff here though!!!). What's most important to understand is that the mp3 was made to make an audio file as small as possible and is a lossy compression, it was then expanded to also compress music and leave it sounding good :-P. I'm sure we've all seen the different options for compression, you can rip at different bit-rates, different sample rates, and a few other options. First of all, CD's have a sample rate of 44.1 kHz so that's really what you ought be using (sample rate is the # of samples taken per second, think of it as how many datapoints used to make a line in excel). Stereo bit rate is simply how many bits are used per second of music, more bps means better quality, iTunes defines good as 128 kbs and their top setting as 192 kbs. iTunes music is NOW 256 kbs AAC (I'll explain AAC later) which is actually pretty damn good, nice improvement Apple (y)

AAC AAC is what Apple uses, and that's probably where you'll mainly encounter it. AAC is sort of mp3 version 2.0, in general it sounds better as the compression / de-compression techniques are better, however it is still a lossy compression. AAC also allows for DRM.

FLAC is a lossless audio compression, meaning that nothing gets lost on playback from the original. This however, takes up MUCH more space on your hard drive (see chart below), however flac is still a 40-50% reduction from the un-compressed size!

-Lossy and Lossless compressions are exactly what they sound like: lossy means some data is lost (but it's good enough to be considered useful), lossless means the un-compressed version is the same as the original.

for comparison, here are file sizes for a 5 minute song in different formats (mp3's & aac's are bitrate then sample rate)
mp3 128 / 44.1 == 4.7mb
mp3 192 / 44.1 == 6.8mb
mp3 320 / 44.1 == 11.3mb
aac 128 / 44.1 == 5.4mb
aac 256 / 44.1 == ??? (don't have any yet, guessing ~13mb)
flac == 122mb :-D

Dolby Digital Yep, Dolby Digital is an audio format (AC-3) which is a lossy compression supporting up to 6 channels of sound. For in-depth information go here

DTS An alternative to Dolby Digital, it is owned by DTS Inc.

THX, THX is NOT an audio format like DD and DTS, rather it is a 'quality standard' of which there are many levels. THX in a movie theater is very different from THX on home media because in a theater, THX Inc. provides special crossover circuitry so there is something being 'sold', for everything else it's really nothing more than something for the marketing people to throw around. Remember, THX is from George Lucas (sort of) and he gave us Jar-Jar Binks, 'quality' is relative here...


Part III: Going from bits to a wave
Now we're going to connect part 1 (the speaker) to part 2 (the data)! Isn't this just super-exciting? Don't you wish your textbooks would occasionally ask if you were having fun? Weee.
Digital audio becomes analog audio through a cryptically named device: the DAC (digital to analog converter).
The inputs AND outputs of a DAC are low-voltage (remember, computers use really small voltages), we want them to be big voltages so they're nice and loud, for that we use an amplifier (amp) which simply turns .001 volts into 10 volts without changing anything else about the signal (well, sort of...).

The DAC and AMP(s) can make or break a system. You can get them really cheap (integrated sound card) or spend hundreds of dollars for just the DAC. I suggest reading around on Head-Fi and A/V Science (AVS) as both boards have thousands of threads on DACS & AMPs (as do we!).
A good DAC will accurately translate digital into analog, it sounds simple but the circuit to do so gets quite complex.
A good AMP will transparently improve volume (no distortion as you crank it up to 11 :-D).

The science going on here comes in two flavors, the first is power cleanliness. Poor power, that is power which has many ripples and fluxuations in itself will pass those imperfections into the system and you will hear those imperfections as they distort your music. The second piece that you're paying for is for the rest of the system to also be clean.
Acceptable tolerances in an electrical circuit are usually pretty high (relatively), also a perfectly clean circuit is almost impossible to find as there will always be some, very very minor, imperfection. This is where quality of components, most noteable capacitors, op-amps, and dacs come in. The good ones cost money, mostly because they are far more rare. Think a Ferrari engine versus a Toyota engine, both are good, one is legen-wait_for_it-dary.

DAC A DAC does it's thing the same way we record audio to the computer (but in reverse), it will take a certain number of samples and use those as the points on a graph, the resulting line is the analog signal they gets produced. A better DAC can handle more samples and produce a better, more consistent waveform, mostly though you're paying for a DAC that can handle more samples per second. You'll also encounter THD here (total harmonic distortion) which is a percentage representing the amount of distortion in the signal, along with dynamic range which is the delta between the largest and smallest signals the DAC can output at once, measured in dB. A good DAC will have a THD under .005% (really freaking small) and a dynamic range of over 100 dB, meaning it will create both the really loud sound of the singer and the really quiet sound of the background cymbals resonating.

AMP AMPs have the same statistics as DACs as they can distort and limit the sound in the same ways. It's important to remember that any time we alter the electrical signal, we can completely change how the music sounds. Money here buys you cleanliness and the ability to turn it to 11, because 11 is 1 more than 10!

Audio Processor This is that nifty thing in your computer, the X-Fi or Xonar or Realtek 889A. It does a myrid number of things, from EAX to OpenAL to DTS & DD. The general chain of events is audio signal -> audio processor -> digital output -> DAC -> amp -> speaker so a sound card WILL be used somewhat even with digial outputs.

*Using the S/PDIF (optical or coax) output will bypass the DAC & AMPs on your soundcard in favor of external units, audio effects will still be rendered into the data

Also to note: Vista handles audio differently from XP, mostly in that it tries to standardize more by using OpenAL as the main means of audio 'pipelining'. EAX is based around Directsound 3D which is only emulated in Vista, thus EAX much run through ALchemy and is sort of hacked into Vista. It is a general consensus that EAX doesn't matter in Vista so I would NOT be too worried about paying to get EAX. If you want a good system, worry about the DAC & amps, not EAX.
In sort:
- If you have Vista, get an Asus Xonar card
- If you have XP, get an Auzentech X-Fi card
- Creative Labs cards are sort of pariahs due to Creative's treatment of its customers (intentionally disabled features in Vista on older cards to encourage upgrading, prosecuted a 3rd party driver maker when he made vastly superior drivers). CL cards have pretty good DACs but really shitty amps, there are mods out there to make them better, but Auzentech & Asus do a better job.


Final Words
Before I leave, a quick word on the hot-topic of the forums: Logitech's Z-5500 5.1 speaker system. If you've read through the rest of this post, then these bullets will make sense:

- The Z-5500 has cheap speakers, they all only have a single 3" driver which handle all frequencies from 150 Hz to 20 kHz. Asking that one driver to do the highs, mids, and lows is not a good idea. It can be done but it is a budget solution
- The Z-5500 have a DAC, AMP, 5 satellites and a subwoofer, and support most formats. Doing all this for $300 (used to be $230, I got mine for $180) is impressive. This system is one of those 'Jack of all trades, master of none' type deals.
- The Z's sound like, and should be valued at, $200 tops. They are not an elite speaker system, they are a budget computer speaker system, they are made to compete with your generic Dell speakers.

If you want high quality audio on a budget, look at 2.0 / 2.1 setups. They may not have as many watts, but advertising watts is like talking about how badass your VTEC is, it's NOT that important. If you omg_wtf_bqq_have_to_have 5.1 then fine, get them (but ONLY at or under $200), for $250ish on up look at home theater in a box (HTiB) systems, they all feature speakers with separate tweeters & woofers and do everything else the Z's do.

Bose falls into the same category. Bose is famous for being small and for sounding good for something that small, it's like having a girl say "well, for a guy with a 2" cock, you're a good fuck", congrats, you're better than a tootsie roll (but not by much).

Audio cables. There is some truth to those high-priced audio cables being important. That truth is that a good cable has better shielding which means that it will be less susceptible to external noise. A bare copper wire will inherit noise from its atmosphere which will make the signal less clean. Buying better cables should be done in-step with the rest of your system, if your system costs $300, don't spend $50 on cables, spend $10. If you're spending more that 10% the cost of your system on cables, you're a dumbass.

The weakest link before you toss all your money into one of the areas I've mentioned here, consider your weakest link. If you have leet speakers & a leet soundcard but shitty 128 kbs mp3's, your system will sound like shit. If you have FLACs & a top-end Asus Xonar card connected to Z-5500, your music will sound muddied and bland.
In general, I feel that:
$ spend on speakers should be no more than twice $ spent on receiver / soundcard
Feel free to correct me. I'm saying that as a baseline, by the time you're looking at spending thousands of dollars on this, PLEASE tell me you've done enough research that you knew everything in this post already!!!


Thanks for reading! I hope this served as a good primer on audio for all of you.

Contents of this thread::
Main Post
Z-5500 Satellite take-apart
Version 1 of the main post
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