Guide: Understanding audio specifications and hardware

[imperialreign]

Been shopping for a new soundcard or speaker setup and wondered what all those specifications slapped on a package really mean? Read reviews about equipment and wondered the same thing? It can all be confusing if you've never read up on audio specs, and even then, a lot of technical jargon is thrown around. I'm going to try and describe what these specs mean in more laymans terms so as to make these specifications more accessible to those not versed in audio equipments, and also try to describe the differences between different speaker hookup connections and equipment, and give some advice to help make component selection easier, and some pointers on adjusting your audio setup as well. I've also included some RMAA output signal spectrums from testing on an unnamed HD audio card, an upper-end Creative X-Fi Elite Pro, and for comparison, the same results from testing the onboard HD audio of my motherboard; and I've tried to explain in a general manner how to interpret these signal spectrums. Signal spectrum tests for audiophiles are like 3DMark06 scores for GPU junkies - they're not meant to be taken as gospel to a components ability, what looks good in spectrum doesn't necessarily mean it will sound good; there are ways to clean up spectrum output that will negatively affect output quality - but we're generally given a good idea of what a component is capable of.

So, let's begin!


For reference, the discernable audio range is accepted as being 20Hz to 20,000Hz - as in, what range of sounds we as humans can hear. Some people can hear beyond this range, some can only perceive sounds below this range; with age, as well, the discernable range narrows. Lower frequency sounds tend to be more easier to hear (and many times even felt), and these sounds will also travel a further distance than higher frequency sounds. Lower frequency tones can cause reverbration, while high frquency tones tend to cause echo.
We can typically discern differences in volume of 3db on average at certain audio frequencies - these values are only accepted as average, and can be different from one person to the next.

Test result spectrum legends: green/white are from testing an unnamed HD audio card, blue/white are a tested X-Fi Elite Pro, and red/white are from testing a SoundMax HD AD1988B onboard chipset . . . all tests were performed at the same settings of 24bit at 96kHz playback in loopback mode using an 8" shielded cable.



I. Basic and common audio hardware quality measurements:

Frequency response: This measurement is a rating of what range of sounds the hardware can produce, from very low frequencies to it's highest frequencies. Ideally, you want the equipment to be able to produce a range exceeding what the human ear can percieve, which would be <20Hz and >20kHz. You will also typically see a db rating for frequency response, and this is a measurement of how much of a volume variation exists across the perceivable hearing range in a playback sample. Ideally, this rating shouldn't exceed a total range of 3db in either direction (plus or minus) from a 0db source.

In this example, you see an almost ideal frequency response - the device in question is able to playback well across the discernable audio range, and there are no spikes or troughs in the output signal within that range, either. In comparison, a perfectly ideal response curve would be flat from 20Hz to 20kHz.

Here we have an even better frequency response spectrum - notice how close the response curve is to being flat . . . a definite marked improvement over the last test.

This result spectrum simply blows my mind - so much so that I ran this test nearly a dozen times; first with the onboard chipset set to Azalia HD standards, then as AC97, I quadruple checked all output settings. I attempted to run the test at 16bit and 24bit outputs, 48kHz and 96kHz sampling rates, I tried using the DirectSound audio mapper, Windows default settings, and with the AD1988B set as default device. I even swapped the line-in plug to the mic-in setting . . . every result returned this ghastly spectacle. Needless to say, this frequency response curve is simply horrible. I am at a loss, if anyone could offer any insight as to the possiblity that I might have done something wrong, I'm more than happy to re-run this test and post the result; but I'm fairly confident that this is correct for this hardware.





Signal to Noise Ratio (SNR): This is a realtive measurement of the strength of an ouput audio signal to the strength of noise within that signal. That is to say, that if SNR is rated at 113db, then there exists a relative difference of 113db between the strength of the output signal to that of the noise signal. In general, anything over 100db is excellent, and the higher the db rating, the better and clearer the signal will be.





Dynamic Range: You will sometimes see this measurement given in place of SNR; dynamic range is a measurement of the signal ratio between the noise floor of an output with no signal to the loudest signal that can be output at a predetermined level, expressed also in terms of db. Again, the higher the db rating specified, the better.

In the example we have an excellent dynamic range spectrum. The spectrum itself is fairly flat through the audio range, with no massive spikes. The single spike at 1kHz is a result of the frequency of the test signal, and is considered normal. The few small spikes in the lower frequencies hint at the possibility of some slight amount of distortion, but lower frequency tones tend to be able to mask this.

Another excellent spectrum. Although we don't see the same flatness as we did with the last test, instead we see a uniform and consistent waveform here. The spectrum itself exists even lower down the scale than our last test, there are no spikes of major importance at any harmonic level.

Here, we see a decent dynamic range spectrum, again, the spectrum waveform is fairly flat through the audio range; although coming in rather high through the lower frequencies; the spikes towards the higher frequencies are not entirelly favorable, though. Although the spikes are not massive in nature, they are still there where ideally in a "HD" component, they should not be. These spikes alude to quite a bit of distortion being present.





Total Harmonic Distortion + Noise (THD+N): A measurement of the amount of unwanted impurities in a given signal. Whereas Total Harmonic Distortion measures unwanted signals in the output, THD+N measures everything that manages to interefere with the output signal, from EMI to harmonic irregularities. Ideally, THD+N would be 0% at any tested level, meaning that the signal being sent into the system is identical to the one being played out of the system; but we live in an imperfect world where our audio equipment will pick up interference and noise and pass it along through the output signal. Be careful reading these specs as well, as an example it's very easy to mistake 0.013% for being better than 0.000013% (the latter is much smaller and closer to ideal 0% than the former is).

In the example, we have an acceptable THD spectrum. It's by far not the greatest, but still acceptable. Of slight concern are the spikes above the 1kHz range - it's more preferable to see spikes like that below 1kHz, where impurities in the signal are harder to hear. Ideally, the THD spectrum would be as flat as possible, with very little spikes at each harmonic level, and no scaling of the spectrum. The massive spike at 1kHz is generally ignored, as the test signal used is 1kHz, the signal will be it's loudest at this harmonic. It's acceptable to see spikes at each harmonic level above 1k as well, but we don't want to see spikes in between these harmonic levels (for example, a spike a 2kHz is ok, while a spike at 1.5kHz would not be). The lower the spectrum exists on the graph as well is more prefered.

With this example, we have another really good THD spectrum. The primary waveform is not entirelly flat, but instead uniform and consistent, and runs the length of the audio range without any sloping. There are a few spikes at a few of the midrange harmonic levels, but acceptable.

Here, we have a decent THD spectrum; definitely not the greatest, as again we see quite a few spikes at each harmonic level above 1kHz, and, IMO, this is representative of too many irregularities for a "HD" component. The results seen above are more preferable when compared to this, are would exhibit fewer negative influences during real audio playback, especially at higher volume levels.






Stereo Crosstalk: This is a measurement of how much an output signal on one channel crosses into a seperate output channel. Typically measured in db as well, by applying a nominal signal level to channelA and reading for that signal on channelB, the db level that the signal is picked up at relative to channelA is taken as measurement. Usually, you'll see the rating as a negative db level, and the lower the better. The higher the crosstalk rating, the less actual channel seperation you'll have, as the two channels will sound more similar to each other as each signal is crossing between channels.

In the example, we have a good crosstalk spectrum. Although there is slightly more channel crossing taking place on the left channel as compared to the right towards the end of the spectrum, which tends to be normal, the actual db levels is still superb, and any actual channel "bleeding" during playback would go unnoticed on all but the most elite setups.

Here, we have an excellent crosstalk spectrum, a well defined climb in the signal which again tends to be normal at such high frequencies. Notice, also, that the spectrum results do extend further below the image on the graph, but I kept the image as it is considering that all these graphs are at the same formatting.

Surprisingly, this represensts a bit better crosstalk spectrum as compared to the first result above; neither channel appears to be bleeding over more. Although, the lower frequencies are a bit unprefered, but easy to live with as most of these frequencies in a multi-speaker setup would be passed on to a subwoofer rather than your mid-ranges.





Intermodular Distortion + noise (IMD+N): A measurement of all impurities in an amplified audio signal that are not harmonically related to the source signal. A little more in-depth than THD+N, this rating is more relative to audio quality as the impurities measured by IMD can cause an audio signal to sound unpleasant, garbled, harsh, distorted or otherwise - usually the result of poor internal or degrading electrical components. Unlike with THD, though, poor IMD can introduce unwanted sounds and tones into a playback, instead of just distorting the signal. The measurement is typically given as a percentage as well, and like with THD+N, the closer to 0% the better.

What we see in this example is a representation of decent IMD+N. The two large spikes, at 60Hz and 7kHz are the result of the two tones used to conduct the test. The spectrum waveform should most flat and even across the audio range, with ideally no other spikes present. The small spikes following the 60Hz and 7kHz range are not ideal, but acceptable, as the spikes themselves don't climb to high at all.

Here we have an excellent IMD+N result - the primary waveform is uniform and consistent, the test signals are clearly seen at 60Hz and 7kHz, and no noteworthy spikes at any of the harmonic levels. The couple of spikes that are apparent are rather small and don't represent too much of a chance of any disturbance to playback.

And this, IMO, about sums it all up - a very poor IMD+N result. Again, the 60Hz and 7kHz tones are easily defined, but every single spike at each harmonic level before, between and beyond the two test ranges bodes very ill of the output quality capabilites of this component. Even at low volume there stands the possibility of subjecting audio output to serious distortion levels.





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So, then, how could we summarize all this as a rule of thumb?

• *Frequency response <20Hz and >20kHz
• *SNR and/or Dynamic range >= 100db
• *THD+N as close to 0% as possible
• *IMD+N as close to 0% as possible
• *Crosstalk <= -90db

The most important specs to look out for, though, are Frequency Response, SNR or Dynamic Range, and IMD

 

[imperialreign]

II. Speaker specifications

So, we've covered the basics of audio hardware specifications . . . but what about speakers? Not all speakers are created equal, and their specs can be just as confusing as the playback hardware you've been looking at; plus, they introduce other specs that need to be taken into consideration as well . . . and what about their design and materials used for construction?

All well and good, but very confusing when manufacturers like to throw out terms and numbers with very little explanation as to what they mean.

So, let's sort through all the mess and get to the bottom of things!

Common speaker specifications:


Frequency Response: Just like with audio playback hardware, speakers have a frequency response rating as well. This is a measurement of what range of frequencies a speaker can playback. Different speaker types are more apt for handling certain frequencies compared to others, as well. For example, tweeters are better suited for playing back frequencies of 2kHz to 30kHz+, whereas a subwoofer is designed to specifically handle frequencies from about 200Hz to about 15Hz (sometimes lower). Speaker type plays a big part in speaker frequency response ratings as well. Although a full-range speaker might be rated between 20Hz and 25kHz, due to the broad range it's designed to handle, it can't always successfully keep up with fast paced audio. Instead of an individual speaker being relied upon to cover the whole audio range, it's more preferred to have "specialized" speakers that are intended to cover certain sections of the audio range.





Signal to Noise Ratio (SNR): Similar as well to audio playback hardware, SNR when used to spec speakers is again a measurement of the strength of the output signal relative to the strength of any noise in that signal. Typically rated in terms of db, again, the higher the db rating, the cleaner the sound the speaker will produce.





Sensitivity: A rating of the sound pressure a speaker generates at a predetermined frequency or frequencies, typically measured in db, based on the amount of power being driven through it. Basically, it's a measurement of how acoustically powerful a speaker is, it's loudness. Although, this is a poor form of specification for a speaker, as testing methods vary between manufacturers, and a higher sensitivity rating does not guarantee a louder of more efficient speaker design.





Rated power, Nominal power or RMS (Root Mean Square) power: This is a vague measurement of the amount of power a speaker can handle, and can be broken down further into more precise measurements. Basically, though, the rated power is the measurement at which the speaker operates at; RMS is the median power rating across the speakers operating range. As a general rule of thumb, speakers with a higher RMS, nominal or rated power tend to be more powerful and louder, but require more power to operate as well.



Peak power: A measurement of the maximum amount of short-term input power a speaker can tolerate before damage is done to the speaker itself. Long term power input at this rating WILL damage or destroy a speaker, short-term power input above this specification WILL damage or destroy a speaker. Of note as well, that it is possible to damage speakers long before the peak power rating has been met as well, which is why it's generally not recommended to operate a system at 100% volume for extended periods of time.



Speaker Impedence: Typically rated at a nominal level, this is the average impedence of a speaker while operating in a typical or normal fashion. If one has to pair an amplifier to a set of speakers, the unit should be rated at or above the speakers impedence level, but never below it. For example, a speaker with a 4Ohm rating can be matched to an amplifier with at least a 4Ohm or 8Ohm output rating, but should not be matched with an amplifier with a 2Ohm output rating.





Crossover Frequency: A rating of the audio frequency boundary in a multi driver setup. This is where the audio output will be split between two seperate drivers so that each driver can handle portions of the audio range it is best suited for. Ideally, the crossover frequency should not exist at the far extent of the two drivers capable output, and the actual level that the crossover fruency is set is dependant on the type of driver, and the crossover filter used.



Crossover Filter: What type of crossover filter is used in a multi-driver setup; commonly high-pass or low-pass. This describes what types of frequencies are allowed to pass through the filter, a high-pass filter will only allow frequencies above the crossover frequency through, while a low-pass filter will only allow frequencies below the crossover frequency.





Driver type: Specifies what type of driver a speaker unit is. Tends to apply more to bookshelf speaker setups than multi-channel configurations. A Full-range driver is a unit that is designed to be able to playback the majority of the audio spectrum, the downfall with these speakers types, though, is that they generally have a hard time keeping up with fast paced music, or very dynamic music.

example of a single-driver full-range speaker


A woofer is a driver designed to playback low frequency sounds, generally in the range of 40Hz to 1kHz; a more specialized form of woofer is a subwoofer, which is meant to be able to reproduce frequencies between, on average, 15Hz and 150Hz.

a woofer speaker


A mid-range is a driver capable of producing between 300Hz to 5kHz, or effectively, the "mid-range" of the audio spectrum.

example of a mid range speaker


A tweeter is a driver capable of producing between 2kHz and 30kHz, sometimes higher.

a typical cone tweeter


A really good speaker setup will have a range of different speaker types, depending on the number of channels; one or two subwoofers (depending on the size of the units), and preferably one woofer, mid-range and tweeter per satellite. The center channel should typically have two mid-ranges and a tweeter, or three mid-range. Ideally, a good setup shouldn't make use of any full-range drivers, but their presence is still acceptable on occasion.






Speaker type: There are two types of speaker designs most commonly found on the market, flat panel and cone speakers. Flat panels are typically very flat, and occupt a very small amount of enclosure depth. They can come in various shapes and sizes. Ideal for setups that tight on space, or where speakers are prefered to not be seen, they are many times easily hidden from plain view. Flat panel speakers, though, are limited in the overall sound they can reproduce; the actual speaker design itself limits the speaker from being able to reproduce low frequency tones, and because of this a subwoofer is essentially necessary. Panel speakers also tend to be accused of producing tinny sounding output, or not being able to reproduce a lot of audio depth, and actual area of audio perception (that is to say, where you can hear the output audio in relation to where you are in a room versus the location of the speaker) is very narrow and limited, many times with the only best location for hearing the full output spectrum being in a straight line from the speaker; some flat panel speaker designs also fall prey to distortions in the reproduction as well. Cone speakers, on the otherhand, tend to take up more space and require larger enclosures; but more flexibility can be had as to their placement without necessarily affecting audio perception. Cone shaped speakers will produce a very full, dynamic output, but because of the amount of energy needed to drive the speaker itself, and an individual speaker's reflex characteristics, can have a hard time playing back very quickly. To ease this issue, more specialized speakers and crossover filters are introduced to the setup (i.e. a tweeter, subwoofer, etc) to "split" the workload across the audio range. This leads to a larger number of individual speakers in a setup, meaning the total setup will take up a significantly larger amount of space. Ideally, though, cone speaker setups are much more preferred to flat panel setups, especially if one is wanting the best audio playback possible.

example of a flat panel speaker


Full-range speakers come in two distinct varieties: single-driver, which I had discussed previously, and multi-driver. Multi-driver full-ranges, typically referred to as "n-way" spakers (i.e. 3-way, 5-way) and commonly found in automotive and marine applications. These speaker units have built in crossovers, and feature multiple driver types within one unit, thus eliminating the issues found with single-driver full ranges. They're great for when space is at a premium and work well with small acoustical environments; their biggest downfall, though, is their highly directional nature, and they also tend to be quite expensive as well.

example of a 5-way multi-driver full-range speaker


Subwoofers come in a variety of sizes, and the size of the unit can have as much of an impact on output quality as construction material used. Generally, smaller subwoofers (i.e. 6", 8" and 10") tend to produce a "tighter" sound, but also can't produce as low of a frequency as a larger subwoofer. Larger subwoofers (i.e. 15", 18", 20") tend to produce a more "loose" sound, but can't play back higher bass tones as easily. Having two seperate subwoofers can offer a trully dynamic low-end, but can be extremelly hard to configure and place the units for best reproduction. In contrast, the medium sizes (12", 13", 14") tend to work the low-frequency range quite well by themselves, but can struggle with the very high and very low end of the low frequency range. Another major difference lies in coil design. Subwoofers can be either of the single-coil or dual-coil variety - to put it bluntly, dual-coils offer more flexibility in their connectivity, and can be a lot more powerful in their playback - not typically recommended for the majority of audio setups, though.

example of a subwoofer


The only other major type of difference in speaker design you might run across is with tweeters. There are two common tweeter desings, cone and dome shaped. Cone tweeters tend to produce a bit more mellow and softer tones, but are highly narrow in their directional in their output. Dome tweeters, on the other hand, tend to produce very crisp and brilliant high tones, and have a much broader directional output. They can be mixed as well for really dynamic high range reproduction, but will require a lot of testing for optimal placements.

example of a dome tweeter


There are also super-tweeter units available, which can easily push frequencies as high as 100kHz. Typically small, but can also come in larger sizes than a standard tweeter - these are very powerful units.

example of a super tweeter







Speaker materials: A good list of common speaker materials can be found here:http://www.crutchfield.com/learn/learningcenter/car/speakersmaterials.html




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So, to summarize everything here:

If purchasing a multi-channel setup, such as 5.1 or 7.1, the two specifications you'll run across the most are frequency response and SNR. With frequency response (rated per the whole system) you want to choose a speaker setups that covers as much of the audio range as possible, preferablly <20Hz and >20kHz.
With SNR, you want the highest rating possible . . . in the case of speakers, preferablly >= 85db (give or take some depending on materials used for construction).

If you intend to piece together a setup, you're looking at a much more involved job as you'll be looking more at individual speaker specs - things to keep in mind: you should preferablly have a midrange, a woofer and a tweeter for each front channel; center channel should have bare minimum of one midrange and one tweeter; rear channels can get by with a woofer and a midrange; at least one subwoofer for the entire setup. I also seriously recommend doing research on various speakers, reading reviews, and asking opinions of others as well if pursuing this course - and that advice can even be applied to other audiophiles as well (there's way too much on the market for any of us to know everything!).

 

[imperialreign]

III. Audio Format, Connectivity, Hardware and Tips


In the audio market, there are a ton of choices when it comes to speaker cables and other hardware, but how do we know which ones are best, or what benefits different products have to offer over another product? Time to clarify all this a bit more, so let's start with connectivity and audio formats:



Analogue versus Digital Audio playback: There has been much debate over the years as to which format offers better audio quality and reproduction capability. In the world of audio playback, both have numerous pros and cons. Digital connections are capable of transmitting more information over a single cable, which greatly reduces the number of cables involved in system. But, ues of digital interconnects will require a reciever unit to be able to decode the audio stream and further pass it along to the speakers. Although, digital connections don't always suffer from the same amount of signal loss over cables like analogue connections, but instead is more susceptible to equipment imperfections.

Analogue connections are very straight forward and just work - you just plug in all your channel connections and you're good to go. Digital, though, can come in various formats, and both the audio source sending the digital output, and your reciever have to be able to support whatever format one has chosen to use. In most cases as well, digital output is limited to 2-channel stereo unless your audio source is capable of digital encoding, which will encode the digital signal to a specific format, thereby preserving the original signal with no downsampling or channel mixing; but again, both the audio source and reciever must be capable of supporting the chosen format.

There are an extensive list of different digital audio formats in use, for more information on the most common formats for home audio, one can visit here: http://www.home-theater-systems-advice.com/digital-audio-formats.html





Tip, Ring and Sleeve connector (TRS): The most common style of audio connector out there, especially in the computer world, and very common with analogue connections. These style of connectors and cables are analogue, and come in a variety of sizes, but the most common are mini-jacks (3.5mm) and stereo-jacks (6.3mm). Both styles function in the same manner, they can conduct a wide range of independent signals, although the average is three or four (one being a ground signal). Mini-jacks are more common with handheld components (CD players, headphones, etc), while the stereo-jacks are more common on standalone home theater equipment. One can purchase adapter plugs that will step down or step up from style connector to another, but in the pursuit of best audio quality possible, this is generally unadvised unless absolutely unavoidable. At the most extreme, one could even purchase connectors and wire your own cable if one so wished.

TRS connectors are entirelly acceptable in any type of audio setup, although for best performance, the cabling type should be taken into consideration. The biggest difference between the two is that stereo-jacks typically use much larger cable compared to mini-jacks - this results in better conductivity and less signal loss through the cable, as well as being more impervious to internal cable damage due to kinking, pinching or otherwise.

Cables with TRS connectors commonly come in either an unshielded or shielded variety. Shielded cables have an extra layer of wire weaving that is intended to be able to capture and ground EMI and RFI from ambient sources, which helps maintain the integrity of the audio signal being passed along the cable. If TRS style cabling has to be used, shielded cable is highly recommended.

example of a stereo-jack (6.3mm) on the left, and on the right a mini-jack (3.5mm)






Deutsches Institut für Normung (DIN): These utilize a circular connector with an array of pins inside of the plug, and can transmit between 3 and 8 seperate connections over either an analogue or digital interface. Typically found with older equipment, they were capable of easily connecting two standalone hardware pieces together through one cable instead of a need for multiple cables. Rarely if ever used, though, for connecting directly to a speaker cabinet, although still very common in the recording industry.

example of a DIN connector





Sony/Philips Digital Interconnect Format (S/PDIF): Although not really a cable or connection standard, as much as it is a digital audio throughput standard. S/PDIF cables are those that meet certain industry requirements for the ability to transfer a digital signal with little to no signal loss. S/PDIF cables come in either a coaxial vareity, with is capable of transmitting in 20bit and 24bit signals, and optical cables, which can transmit upwards of 32bit and at a higher bandwidth. S/PDIF is almost defacto in the audiophile realm when it comes to the best audio quality possible.




Radio Corporation of America jack (RCA): RCA connectors and cabling started as another analogue means of transmitting a signal, albeit through a coaxial cable, and as technology has advanced, they've proven capable of digital communication as well. RCA cables offer a few advantages over TRS connectors - although their cabling tends to be a bit smaller than stereo-jack cables, but still thicker than mini-jack cables, RCA cable only transmits one signal per cable; which leads to better signal strength through the connector, and can make for hook up to be easy and straight forward as the plugs themselves are almost always color-coded. Their biggest downfall, though, is that which each cable only supporting one connection, multiple speaker hook-ups can lead to an over abundance of cables, which can make for a chore in keeping everything organized and straightened. RCA cables can also be S/PDIF rated, meaning that particular cable meets S/PDIF standards.

example of RCA coaxial connectors





Toshiba Link (TOSLINK): These connectors use fiber-optic cable for transmitting digital data, as compared to a typical coaxial cable. These connections are capable of transmitting more data and at a faster rate than typical S/PDIF coaxial connections, and with no loss to signal strength. Whereas typical coaxial S/PDIF tops out at 20bit or 24bit connectivity, TOSLINK is capable of 32bit or better, and at a higher bandwidth as well. Biggest downfall with these cables, though, is their pricing.

example of a TOSLINK optical connector






Speaker and Audio Cables and connectivity: There are about as many different varieties avaiable for speaker and audio cabling on the market as there are speakers. Cables can range from your everyday copper strand speaker wire to the highly exotic pure silver (and sometimes even pure gold) speaker wires. The question and debate still raging, is there really a difference between different speaker wires? For the most part, there is, but unless you're running super high-end setups (read: over the $2500 range) you probably wouldn't be able to hear any difference at all. One can easily use standard copper strand speaker wire and still be more than happy with your audio output. The next step up, where you can usually hear a difference is with Oxygen Free Copper wire. Beyond that is silver coated oxygen free copper wire. The most exotic speaker wire you're liable to come across is pure silver and oxygen free pure silver. These types of speaker wire can become stoopidly expensive.

My personal recommendation is to stick with oxygen free copper wire. It offers better conductivity over standard copper wire, and drastically reduces the possibility of internal wire corrosion over time that is common with standard copper.

Speaker wires tend to come in a variety of gauges as well. Wire gauge over long distances plays a heavy role is the overall impedence of a wire. As a rule of thumb, I recommend 14AWG for full-range, woofers anad subwoofers (depending on the power rating of a sub, though 12AWG might be appropriate), 16AWG will suffice for midrange speakers and dome tweeters and super tweeters, 18AWG is typically alright for cone tweeters.



There are also many different styles of connectors one can use for connecting speaker wire from the output unit to an enclosure, which typically depends on the type of binding posts used on the enclosure itself. Wire terminations typically also come in gold-plated and standard varieties. Gold-plated is recommended, as the conductivity properties of gold contacts help to reduce signal loss over the connection. The most common connectors used are bannana jacks, and offer a strong connection and eas of connectivity to an enclosure. Typically recommended for the DIY projects, as they are very easy to hook up and remove at a later date, but due to their means of connection, they can easily wiggle loose from their female port if speaker enclosures are bumped or moved around.

example of gold-plater bannana plug connectors on the left, and a female banana connector on the right



The next most common wire terminator is a spade connector. These also come in standard and gold-plated varieities. These require more effort to connect to an enclosure, as their binding post makes use of a flat plate which is tightened down onto the connector by means of a thumb screw. Spade connectors offer the same quality of a connection as bannana plugs, but offer a connection that will not wiggle loose.

example of a gold-plated spade connector on the left, and a spade connector binding post on the right





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Hardware:



Amplifier: This is a unit that essentially takes input from the audio source, and amplifies the audio signal to be sent to individual speakers. A necessity with more powerful speakers and multi-channel setups. Although, the amplifier itself is slowly becoming obsolete within the home audio world, as a reciever unit almost always incorporates an amplifier, as well as other capabilites.

example of an audio amplifier unit






Reciever: This is a unit that is capable of receiving an analogue or digital input from an audio source, decoding the signal (if digital), amplifing the signal and outputting it to the speakers. With digital signals, most recievers support a multitude of decoder formats. Recievers are even capable of offering special signal effects and presets, and some also come with built-in mulit-channel equalizers as well. Almost an entirelly necessary component, though, with digital audio; they're quickly taking the place of multiple standalone components.

example of an A/V reciever unit





Equalizer: This is a seperate unit that recieves signal input, adjusts audio frequencies within those signals, amplifies them (in some cases), and outputs them to the speakers. Equalizers are essential if one wants the most control and configurability in any audio setup. They tend to come with a multitude of "band" support, meaning how many audio bands they are capable of adjusting. The more bands an equalizer has, the better. Simple equalizers might only offer 7 or 9 band equalization, whereas higher-end components might be upwards of 18 to 20 or more. Audio recording equalizers can hit upwards of 30 or more individual bands. Preferablly, the more bands an equalizer has, the more control you'll have over audio adjustment. Although, with small acoustical environments, one can easily make due with a lower number of accessible bands, but for larger environments, you want to be able to have more bands available. Truly complex upper-end units will sometimes even offer an array of control over seperate audio channels as well.

example of a mulit-band equalizer unit



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Tips for setting everything up and making adjustments:



Placing your speakers: Although mostly straightforward and simple, there are some points to consider when placing your speakers. For starters, if possible, a subwoofer should be placed with the cone of the speaker facing the floor. This will eliminate a lot of the "thump" type of noise associated with speaker hits. If the enclosure design does not allow for such a placement, have the speaker facing away from where you will be doing the majority of listening.

Ideally as well, don't place your speakers right up against a wall. With smaller speakers, about a foot away from the wall should suffice, with larger woofer and subwoofers, you'd want to consider closer to 3 feet. This will eliminate a lot of audio reflections that will eminate from the rear of speaker enclosures (yes, cone speakers still produce some degree of sound to their rear).

This stage will require a lot of experimentation as well, as you'll have to determine what positioning is best for your acoustical environment.





Adjusting subwoofer/amplifier gain: If your subwoofer has a gain control, you can adjusted the power being sent to the subwoofer based upon the relative input signal strength to the unit. A good rule of thumb is to normalize any equalizer settings (set to a flat curve), adjust your speaker volume to about 30%-35% - while playing a track that has decent and deep bass to it, slowly increase the gain on the subwoofer until right after you start hearing the subwoofer producing output - further adjustment might be necessary based upon your acoustical environment, subwoofer type and personal preference. This will help to ensure that you'll have great subwoofer output, but not enough to drown out the rest of your speakers.





Adjusting equalizer settings: This is a little more complicated, as the actual best curve will depend entirelly on the listeners subjectivity, and the acoustical environment itself, there are many variables that affect how speaker output sounds. To start with, normalize all equalizer channels, and set your voulme output to about 50%. Make sure that you satisfied with your speaker placement, and your subwoofer gain settings. Play an audio track that you are extremelly familiar with, and adjust one band at a time - make your adjustment, and listen to the track, if need be further adjust that band until it sounds acceptable. Move onto the next band and repeat the process. You may also have to go back and readjust certain bands as well, as output will continue to change during adjustments. This can be a very time consuming task, but is well worth it.





Improving speaker quality and output: There are some tricks one can use to improve the quality of your speakers, and eliminate a lot of unwanted noise (some of which you won't even notice until after some of these changes). First up, sound insulating an enclosure. If your speaker enclosures are large enough, you can remove the speaker and line the inside of the enclosure with 1"-1.5" foam padding. The foam will absorb and deaden an extra noise produced to the rear of the speaker during output. Keep in mind, though, that powerful speakers can become hot during extended periods of play, you want to make sure that there will be enough room within the enclosure for the unit to breathe and radiate heat adequately. If one is concerned as to space constraints, you can also use .5" foam padding instead.

Another trick that can be used is to place a gasket material under the speaker frame itself - this will help to eliminate speaker rattle produced from a speaker frame being in contact with the enclosure. High-quality, upper-end speakers should already have some kind of gasket material under the speaker frame. If not, there are a few choices as to what one can do for gasket material. The cheapest option is to purchase some cork gasket material from a hardware or automotive store. This gasket material will typically come in a sheet, you will need to trace out the speaker shape and cut the gasket from the sheet. Cork material will also absorb some noise as well due to its density. Rubber gasket material can also be used as well in place of cork, and will still function nicely. The most preferred method, although can be costly, is to make a gasket from a sheet of silicone gel material, these can typically be found in arts and crafts stores, cooking stores (silicone bake sheets), and sometime automotive stores. Some will even have adhesive on one side of them as well. As a finaly option, silicone caulking adhesive can be used (although very messy), make sure, though, to follow all precautions on the tube as fumes can be toxic. One would apply the silicone caulk to the speaker frame itself, and then place against the enclosure and mount the speaker, then wiping away any excess. Most silicone caulks will cure in about 24 hours.





Well, that concludes everything I can think of at the moment. If I remember something else beneficial I'll edit it in later on. Hopefully I've been able to help demystify a lot of the audio realm, or at least presented any information the others can find useful and valuable.

Again, though, I'm no audio "expert," I've just be around it all for a long while - if anyone has any corrections, additions, second thoughts or recommendations, I'm more tha willing to add them into this guide or make any changes necessary.

Happy listening!

 

[Cold Storm]

Very good guide my man! Very good guide!

 

[Deleted member 24505]

Nice bud,but you never covered speaker wire

This is what i use.

 

[imperialreign]

Nice bud,but you never covered speaker wire

This is what i use.

I kinda bundled talking about audio cables in with their typical connectors . . .

but, damn, I forgot to cover cable gauging (if intending to make your own cables) . . .

I'll edit it up here at some point today

 

[oily_17]

Very nice write-up there Imperial.Will help give a better understanding of audio specs.

You seem to have a lot of useful information in there,only give it a quick read through now but will take time to read it all later when not so busy.

 

[AsRock]

Sweet good job there , i just love these type of tweeters

There as as you say and can easy replace a 5+ speaker setup if paired with decent mid\low speakers.

My favorite are the cloth type ones.

Wish i could get my original TANNOY Mercury's back dated back to 82\83. If you can get me a pair i'll pay good for them hehe. If i remember right they have a hard done peice behind the cloth you see normally white and are liquid cooled.

Foam speakers can be good but have to watch them as the years go by as the foam can break down and crack. a friend of mine had the issue and bicycle glue stiffened them a little but fixed them all the same jusy do not apply to much.

 

[imperialreign]

Sweet good job there , i just love these type of tweeters

There as as you say and can easy replace a 5+ speaker setup if paired with decent mid\low speakers.

My favorite are the cloth type ones.

Wish i could get my original TANNOY Mercury's back dated back to 82\83. If you can get me a pair i'll pay good for them hehe. If i remember right they have a hard done peice behind the cloth you see normally white and are liquid cooled.

Foam speakers can be good but have to watch them as the years go by as the foam can break down and crack. a friend of mine had the issue and bicycle glue stiffened them a little but fixed them all the same jusy do not apply to much.

I'm not big on cloth speakers myself, I personally prefer IMPP composites using butyl surrounds, but you don't see that much in the home audio market - more common in auto audio components. Only problem with more rigid cones, is they tend to require more power to drive due to the extra stiffness and they tend to have a rough time with fast reproduction - which equates to a need for more speakers

 

[Deleted member 24505]

What do you think to these drivers? on my mordaunt short ms901 signature's

 

[AsRock]

I'm not big on cloth speakers myself, I personally prefer IMPP composites using butyl surrounds, but you don't see that much in the home audio market - more common in auto audio components. Only problem with more rigid cones, is they tend to require more power to drive due to the extra stiffness and they tend to have a rough time with fast reproduction - which equates to a need for more speakers

Yeah cloth can have issue's like dirt as they used a oil like substance on them. Maybe you know what the stuff was lol.. But tweeters like those used to be made mainly by one company even Panasonic had them with the crappy midi system but Dayum the speakers rocked.

What do you think to these drivers? on my mordaunt short ms901 signature's

OOps my bad made me think of B&W sheesh. B&W or some thing like that ?.. I yeah hated the hell out of them.. In fact hate them metal type tweeters.

EDIT: if they are by B&W i truely hope there better than the ones i had as they were flat and dull and sharp sounding.

I know the name of the ones i had were B& some thing. Long time ago that was lol.

EDIT: I thought i have another look around and these sucked like no bis lol
http://www.gabrieltan.addr.com/BW_Series_500.jpg

These are like the TONNOY's i so liked so much i just cannot remember the tweeter being rubber ( maybe it's just the light fair sure of that ). These could be them with wood covering put on them ( that sticky plastic stuff). I'd be really happy if some one finds some of these for me lol.

I allways remember the missions 701's having rubber tweeters did not like them all that much and was allways worried about the foam.
http://www.gabrieltan.addr.com/Mercury-S.JPG

I've had loads of pairs of speakers over the years but only some stuck in my mind.

This site is bringing back some nice memorys
http://www.gabrieltan.addr.com/speakers archiv.htm

 

[imperialreign]

What do you think to these drivers? on my mordaunt short ms901 signature's

IMHO, they look like something I would completely pass over in a store;

for the simple fact with the midrange that there is no visible attachment between the cone and the coil, which leads me to believe that it has some kind of odd dual-cone setup, which to me means more thought was given to form over function.

I don't see anything wrong with the tweeter, though - should reproduce quite nicely, IMO.


My personal favorite brand for audio components is PioneerElectronics, no other company, IMO, has been able to offer the same exceptional build quality, audio quality, and manufacturing quality at such competitive pricing . . . but that's what you get froma company that has been solley focused on audio products for decades.

If you're looking for a good cabinet design for an individual channel: http://www.pioneerelectronics.com/PUSA/Products/HomeEntertainment/Speakers/TAD-HomeSpeakers/ci.Reference+One.Kuro


or something for PC use that's truly unique: http://www.pioneerelectronics.com/PUSA/Products/HomeEntertainment/Speakers/Pure+Malt+Speakers/ci.S-A4SPT-PM.Kuro

 

[oily_17]

or something for PC use that's truly unique: http://www.pioneerelectronics.com/PUSA/Products/HomeEntertainment/Speakers/Pure+Malt+Speakers/ci.S-A4SPT-PM.Kuro

Wow..really nice set-up there,would love a set of those.Had to laugh at the quote from one of the reviews -

"It's just funny that when you soak in whiskey, you get into fights. When wood soaks in whiskey, it produces rich sound. Go figure."

 

[Deleted member 24505]

Heres how the driver works.

Mordaunt short make very good hi-fi speakers,Not my favorites but very good.These are bi-wireable wth gold plated binding posts which take bannana plug connections too.

 

[farlex85]

Wow that's extensive. Thanks man. I'll be sure to check this out once I get in the market for some audio (hopefully soon). Make it stick.

 

[imperialreign]

Heres how the driver works.
. . .

Mordaunt short make very good hi-fi speakers,Not my favorites but very good.These are bi-wireable wth gold plated binding posts which take bannana plug connections too.

thanks for that, that greatly clarifies how the unit is assembled . . .

so - I'm guessing the actual cone, then, is some high-strength and non-flexible type of material, then . . . damn, that surround has to be made of some super strong and resilient material to help pull the cone back to it's original position.

 

[Mussels]

all thats left is needing more detail into the digital vs analogue. For example, digital only allows 2.0 audio unless its pre-encoded (DVD, Blu ray, auzentech sound card)

 

[imperialreign]

all thats left is needing more detail into the digital vs analogue. For example, digital only allows 2.0 audio unless its pre-encoded (DVD, Blu ray, auzentech sound card)

hadn't even considered adding in anything on the different audio mediums - I'll edit that in tomorrow

 

[Mussels]

oh and dont forget HDMI in that digital list. i know a lot of people who went and got ATI cards for HDMI audio, only to find their games stuck in 2.0 sound.

 

[Deleted member 24505]

I thought HDMI can send out a 5.1 signal.

 

[Mussels]

I thought HDMI can send out a 5.1 signal.

its digital, so it can only do 2.0. If its ENcoded however, it can pass it through to a DEcoder (example: DVD with dolby digital audio, to my logitech speakers of sexiness)

the problem is, on a PC unless you have an auzentech soundcard... you dont have an encoder. games dont come in dolby digital, so you're stuck with 2 channel PCM sound.

 

[Deleted member 24505]

I have the digital out from my x-fi XM using a coaxial cable going to my sony av amp,i use the amp in 5.1 mode so it upmixes game to psuedo 5.1.It sounds good enough in games.

Or maybe i should be using the analouge outputs to the amp,which is the best way guys?

 

[WarEagleAU]

Very awesome Imperial. I gave it a quick read through but Im gonna go more in detail with it later. This will definitely help alot of folks out. Hey Mods, can we get this stickied or articled?

 

[imperialreign]

made some updates - will add some more later

 

[thoughtdisorder]

made some updates - will add some more later

Awesome guide Imperial! Thx! Very well written!