AUDIO TECH article

Cables

Cable: Analog and digital

Without cables we can't even make sounds out from your speaker. In the future there may be the day that there is no cables necessary in your audio system. However, I guess, even when the time comes, pros will use the cables such as those made by the manufacturers listed here. The history of analog audio is rather long and mature than digital audio. You can't belittle it.

First there are two categories of cables: Analog and Digital. You will need both. Analog cables vary dramatically in price and in quality. Digital vary less. You would easily notice that digital cables are only conveying the digital info that recreates the waveforms and other info from one place to another. In case of analog cables also conveys the waveforms but the difference is that digital gets affected by the material environment far less than analog, and that analog waveform is more wholesome than the digital waveform made of dots. You know digital audio is at this point of time sort of fake audio reprint of the original waveform in the nature or by analog audio, and analog audio is sort of wholesome one time reprint based on the actual wave vibration. If you don't understand this crucial difference, at the earliest stage of your making a home studio, you will hurt yourself. You must know "analog audio" is, no matter how far the technologies go, always used on that foundation. You know that's why either the inlet (the recording of sound =microphone) or the outlet (speaker) in the world of our audio system is always analog.

Now I figure you get a basic picture of Analog and Digital and that you know Analog is the original blue print in capturing sound and is also basically the sound coming out of your speakers or headphones. This easily reaches to one conclusion that Analog is the most important basic. So simply you should first invest on the analog lines in your system. Analog comes prior to Digital. Now take a look at what types of analog cables are in the audio world.

Analog cables: Balanced and Unbalanced

These below are the standard cables used in the music production industry. They are categorized by its jack types.

Jack Type	Common Level	Signal balance	Common Standard Name
XLR	+4dBu	Balanced	Pro (Mic cable)
TRS Phone	+4dBu/-10dBv	Balanced	Pro (TRS line cable)
Phone	-10dBv	Unbalanced	Consumer (Line cable)
RCA pin	-10dBv	Unbalanced	Consumer (Pin cable)

In this chart, upper is more expensive, professional, resistant for noise. The difference between XLR and TRS phone is just the difference of the form of the physical jack. The mechanics of both cables are the same. The difference between TRS phone cables and phone cables is just whether they are balanced or not (TRS phone jack has two lines carved on its jack head while unbalanced phone cables has only one line carved. So you can recognize either one by its looks.).

The difference between "balanced" and "unbalanced" is that the line is earthed or unearthed. Balanced cables (Either XLR or TRS phone) has 3 point connection in its construction: (XLR) 1= Earth, 2= Hot, 3= Cold, (TRS) Tip, Ring, Sleeve are connected to Hot, Cold, Earth so that the signal is balanced. Unbalanced cables (usual phone cables or RCA cables) has only 2 point connection: Only Hot and Earth. There is no inversion of the audio signal involved. With positive only, it's called "unbalanced signal".

As you may see, "Balanced" cable has more resistance against noise with already described Hot-Cold inversion (+-cancellation) effects. So pros mainly use "Balanced cables". Especially XLR cables (So-called "mic cables"). Then which is better, XLR or TRS? XLR has more solid bite on its jack thanks to its physical construction. XLR male jack has 3 separate pins and they lock to its female quite solidly. TRS jack has such a simple plug like usual phone jack that it may slip off after you plug it in. Lock mechanism is very primitive compared to XLR jack. With all these considered, pros use XLR so-called mic cables for almost all lines inside their studio except sometimes they use TRS cables.

There may be opinions as to the taste of sound each cable makes but in spite of that I would recommend your important cables must be at least all "balanced" cables, which means XLR mic or TRS phones. Other things depend on what gears you have because you can't use XLR cables to a drum machine which only has a pair of unbalanced phone jacks. In this case you simply use unbalanced phone cables or if the connection is such a long distance you convert them into balanced signals with unbalanced-to balanced converter. But usually using simple phone cables or TRS cables are fine because your mixer or audio interface usually have TRS phone input jacks nowadays. Actually in our studio we have XLRs for the heart of the system but also have many TRS phone ins & outs here and there.

What you should keep in mind about Balanced signals and Unbalanced signals here is that Balanced can handle the Pro-sumer level "+4dBu" but Unbalanced can usually only handle "-10dbv". This simply means Balanced signal is a signal hotter than Unbalanced. This makes sense because Balanced line is more noise proof than Unbalanced so that Balanced can set its audio level higher than Unbalanced. Why it's +4dBu is it's just because it's one of the standards the industry set. It's just working that way. Pro: +4dBu and Consumer: -10dBV. The former Pro-sumer hotter line means something in music production because "+4dBu" has an advantage when you record a signal. If you record it hot, you can expect better Signal to Noise Ratio, which means a cleaner signal. Which means these balanced cables usually has more dynamics in its signal than usual unbalanced cables like phone cables with the added effects of its shield construction of the cables themselves (although there seems to be good expensive phone cables out there.). But for example low impedance electric guitar signals are always on the line level (-10dBV) since electric guitars are made that way. So the only option is you choose a good guitar cable with a good, appropriate shield and make the distance of the cable as short as possible. If you need to wire a long distance for some reason, what you can do is to use DI (a type of unbalanced to balanced converter) and change it into XLR cable and wire the long distance with XLR. Many guitar amps or bass amps has DI lately and there are good DIs out there, so usually almost all guitar pros have at least one DI in his or her rig.

Almost all synthesizer and modules only have line level phone jacks. Also many mid-level rack effects have only line outs. So I think you will need line cables. Basically I only use TRS balanced for line cables because TRS cables are not expensive today. As TRS can handle both balanced Pro Level and unbalanced Line Level , once you install TRS cables you don't have to bother about phone cables any further.

Not only balance/unbalance polarity affects the signal handling, also the make (structure and materials ) of the cable itself affects the quality of the signal conveyance. You will see how much one cable can be expensive if you look for a hi profile audio cable. Some cables are just expensive because they are using esoteric materials (PVC, Silver, etc. usually which are superior in signal conveyance to usual copper) or/and their structure is a bit more complicated or just different in the making usually to better signal conveyance and noise resistance (aluminum wrap shield, 3 core structure etc.). What I mean here is there are many variations in cables other than balance/unbalance jack type. Then what make of the cable should buy? Okay if we probe deep into the make of cables, this column will get complicatedly longer. I will leave that esoteric probe to you, so here let's focus on the cables of usual home studio use.

Cable brands and Jack parts brands

Usually in home studio wiring, there is no need for long distance conveyance. So I suggest you don't care too much about the make but try to buy the cables of reliable pro audio brands. Below are some of the respected analog audio cable manufacturers that are acceptable and prevalent in the pro studios.

Monster Cable, Belden, Canare, Mogami

There are other cable makers like Vital Audio, Zaolla, Hosa etc from super expensive to cheap. However from my long experience and from the point of view of cost effectiveness, and the sound balance, professional durability, the right type of cables from the brands above are worth the price, and satisfactory in usual professional applications. In my opinion their cables have durability, good combination of parts, priced appropriate, and finally they sound natural, musical, reasonably fat, and low noised.

In my studio I use all of the above. I rely a lot on my custom made Belden in the critical main part of our wiring system. For mic cables, I use mostly Canare. Sometimes Mogami. Canare has great cost performance. They are reasonably priced but their performance is very good. Canare is well built so it never got broken in my studio and sounds always natural to my ears. Canare is my reference along with Belden. I recommend Belden for multi snake cable which you might use in your connection between your mixer and your audio interface (or AD/DA Converter). They are well built, sounds professional. But take care to use a good jack parts in making the snake cables. Respected companies of receptacles and jacks are: Neutrik, ITT, Switch Craft. Among these I think Neutrik is fine. This company seems to be very diligent in getting better and recent X series has reliable locks. I admire Neutrik.

Getting back to the cable talk, certain audio connections, I use Monster Cable from spot to spot. Among these four brands, my impression is that Monster Cable seems to be the maker of specialty cables. So I think Monster is good for special connections. For example, I have ready Monster for electric bass and guitar. But I have other cables for guitar and bass, too. I think Guitar cables and Bass cables can have identity and outstanding characteristics so I guess you can pick any you like. But here you better buy the stuff that cleared in the durability and the noise department. Nothing is worse than easily breakable cables and noisy cables.

Digital cables (and word clock and A/D/A converter)

I guess I talked enough of analog cables. Now let's move on to digital cables. As an audio manipulator, honestly speaking, I don't care much of digital cables. That's because digital is nothing but the conveyance of mathematical digital information captured from the original analog audio information. So more important should be the precise capturing of the analog source, which means actually the A/D/A converter.

So naturally my philosophy is that it's wiser to invest your hard earned money to A/D/A department than to the digital cable department. I never saw audio professionals who are keen on getting hi-end digital audio cables than hi-end A/D/A converter or analog audio cables. Like I said before as analog is the source and the start of the whole point of our music production, our main concern should be with analog lines.

Well, so should we skip this part, digital cables? Well, but you would be very lost in what to buy. So I will recommend some that I thought that worked okay in my experience although I don't explore hugely in the digital cable department.

Although it's digital and seems less sensitive than analog, it's no good to fail in the digital lines because if it fails the recorded digital waveform in your ProTools or any audio production software would be such an unusable waveform. I mean in digital world errors in the information all become some sort of steep noise in audio. So if digital lines fail, it usually become a hideous noise or polarity bias. This is certainly no good! So one caution is you better choose a well built, reliable cables. Basic philosophy is the same as of analog cables.

Before recommend certain cables, we have to note the importance of world clock. What is "Word Clock" anyway? Word clock is as important as audio A/D/A converter in the digital audio, because as all digital audio is remitted by certain timing as to its clock's sample rate, if the timing precision is not good, the timing is delayed and cause the fore-said digital failure. The timing precision is firstly based on its clock generator. Many pros take care much about the clock generator so they sometimes buy a very expensive word clock generator. But today there are word clock generators that cost less than $3,000. So if you can afford and need, I recommend you think of buying a generator in the future. But in the real world audio interfaces or digital mixers can generate word clock (usually only one line) so in the home studio setup there is rarely a need for a word clock. But if you use one you would experience an audio upgrade especially in its clarity. So you should keep in mind that it's pretty important.

A/D/A converter is a device that translate between analog audio and digital audio. In DAW it's an indispensable tool. Usually you would get away with your DAW audio interface because it may usually have some A/D/As. But if you try some respected converters, you would notice a sound upgrade in many ways. A/D/A converter is also very, very important in the today's audio production.

We have to leave topics about Word Clock and A/D/A converter to other columns. Now we have enough foundation for digital cables. Below are the digital cable manufacturers that I have used and thought usable or I assume good.

Monster Cable, Belden, Canare, Mogami, Apogee, Audio Technica, Hosa, Zaolla

Almost the same manufacturers as analog cables. One common tendency is that most manufacturers only make cables in short length. It's said digital cables should be as short as possible. Most cables are usually less than 6 meter. Well, in my experience ABS/EBU XLR and ADAT can be longer than 6m without problems. but I feel consumer S/P DIF should be short. Among all of these formats I like ADATs best because it can convey with a single line 8 channels of audio at 44.1 (48) kHz and 4 at 88.2 (96) kHz. And ADAT seems the most stable. One drawback is that it AES/EBU XLR also seems stable. So I recommend use ADAT or AES/EBU. There are other formats like TDIF, etc. But they are not popular. There are some good new formats are getting popularity. What I think very promising is MADI. It can convey amazingly 64 channels of audio at 44.1 (48) kHz and 32 at 88.2 (96) kHz and 16 at 176.4 (192) kHz by a single word clock cable or optic fiber cable. That's good. Maybe in most home studio this is way over the need. But for a pro studio or the composers or engineers who handle many tracks might find MADI very attractive.

Now here goes the chart of digital cables.

Format	Jack Type	Common Name	Number of Channels/ Method/ Sample Rate
AES/EBU	usually XLR	Pro	2ch by single line/ 1ch by dual line. Up to 192khz.
S/P DIF	usually pin	Consumer	2ch by single line/ 1ch by dual line. Up to 192khz.
ADAT	Optical	- (Professional)	8ch at 44.1 (48) kHz, 4ch at 88.2 (96) kHz. Up to 96kHz.
MADI	8ohm BNC or Optic Fiber	- (Very Professional)	64ch at 44.1 (48) kHz, 32ch at 88.2 (96) kHz, 16ch at 176.4 (192) kHz. Up to 192 kHz.
Word Clock	8ohm BNC	-	-

I recommend you try yourself the cables from the manufacturers above. But I have no problems with AES/EBU cables from Apogee, S/P DIF cables from Apogee, Audio Technica, ADAT cables from Hosa, Word Clock cables from Canare. They are all fine and okay. In my studio I use many ADATs and AES/EBU but in the future I am thinking switching to MADI when it becomes popular and less expensive. I didn't note here but there are also some audio formats using Cat 5 LAN cables. I think this cable is more handy than MADI's BNC cables because LAN cables are more flexible than BNC. However there are many LAN audio formats in the industry (Yamaha LAN, Roland Digital Snake etc.) and LAN audio is still chaotic and it seems at this point of time it hasn't developed enough to be even taken by third party companies of pro audio equipment manufacturers. So we have to see more years to come LAN audio formats acquire maturity.

Now I end here the 1st column of "AUDIO TECH". I would hope this would more or less help you guys to build your home studio in a right way. After all you have to check and explore yourself to get what you want. People have different tastes and they are unique when it comes to music. And moreover music creation needs originality. But there is certain commonly I think I tried only the universal facts around the professional environments that comes before the originality. Once you've cleared the pro sound requirements, then you can go any way you want.

I thank you for patiently reading this column.

Apiece N-even Jones

2008/06/10

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