Computer DJ Guide - Basic Hardware You will Need

Computer
The type of computer you use is more of a subjective issue these days, as most modern PC's are more than powerful enough to play music and video on.
Some "higher end" (read expensive) software packages, may have hardware requirements above and beyond what is of the norm. They will mostly offer to sell you this hardware as well at a premium price, so read the fine print of your software and see if it can run on most standard computers.
Laptops are becoming more and more popular these days due not only to their increased power, but also their declining price tags. The biggest advantages to a laptop are the size and weight, which is also one of the main reasons many people switch to computer systems for DJ'ing.
Standard desktop computers are used as well, but don't lend much to the aesthetics of your system when set up on stage. They are easy to work on, cheap, and easy to get replacement parts and upgrade.
Rack mount systems are visually appealing, and provide a professional appearance, although they can be expensive, hard to work on, and a pain if you want to upgrade.
For the DJ just starting out in the digital arena, we like to recommend a laptop computer. It is quick and easy to setup, and has plenty of power to do any basic and many advanced types of jobs. It can also double as your home or work computer, although we tend to recommend that you don't put too much garbage on it.
You can easily upgrade the sound device on a laptop to a plug in PCMCIA type card or a USB device, so that is no longer an issue.
One of the more important criteria's to look for in a laptop, is a good service plan in case it should fail for some reason. You don't want to be waiting 2 weeks for a replacement. Look for a service plan that will give you a replacement with quick turn-around time and on-site service if possible. Also, make sure you can upgrade your laptop fairly easily - most laptops are not designed to be worked on by the casual computer user.
Processor
It used to be that the most CPU intensive part of DJ software was the actual decoder that decodes and plays your MP3, WMA, etc. This has changed, as most decoders in use in the software out there, were written with processors much slower than today's. The newer breed of software is much more graphically oriented, and may include video functionality as well, but the underlying decoder engines still do the same thing they always did. Graphics and video are much more intensive CPU wise, than audio decoding, so depending on the software application you will be using, you might have different requirements as far as CPU goes.
The make of the processor you use is not really an issue, as both Intel and AMD make a full range that will do whatever you would like them to. It becomes more of an issue of what type of processor, and what speed it's internal clock and bus runs at .
Pentium 4 processors are the most popular, although the AMD Athlon and 64 bit processors have made many inroads due to their usually lower price tag.
Intel Celeron and AMD Sempron processors are the lower priced models you will see advertised in many systems, whether they be laptops or desktop/racks. They usually have much less on-chip cache memory, and although they work fine for most computer applications, they are not the greatest speed demons in the world.
For full blown DJ software, we would recommend the P4 or AMD Athlon or 64 bit chips.
A word of advice on 64 bit chips:
99% of the software on the market today, cannot take advantage of a 64 bit processor. Most of the compilers on the market (a compiler is what a software developer uses to build their code), do not take advantage of the 64 bit chip, and Windows is still a 32 bit OS. They are generally faster all around, but you will not see any major real world differences until 64 bit Windows and the associated compilers come out, and then it will be some time before the applications software is rebuilt to take advantage of the extra registers, memory, etc.
It took seemingly forever for Windows to come up to full 32 bit speed, so expect to wait some time to see the full advantage of 64 bit - until then, it's a great buzzword to use around your computer illiterate friends, and it's great that AMD took the lead here, as there is finally some good competition in the processor world that might speed things up...
Memory
Today's bloated operating systems and software eat memory almost as fast as you can put it in. Just to run Windows XP, you will need at least 256MB to keep it from crawling itself to death, and 512MB to get a decent response from your software.
The sweet spot for most people will probably fall between 512MB and 1GB of RAM for typical usage. If you will be running video, you might want to push it up to 2 GB.
Unless you are running dual processors, you probably won't notice much effect with more than 2 GB, and there is a point of diminishing returns, as the software you are using will allocate memory for audio and video buffers only up to a given size. Some people will say stuff it with as much as you can get, but again, if your software cannot utilize it, you are wasting your money, and the memory more than likely won't work in the next machine you get with a different processor and bus speed.
You can get a rough idea of how much memory your software is actually using by opening up Task Manager (right click the button bar at the bottom of the XP desktop, choose Task Manager) and looking under Processes. This will tell you how much memory each individual process is using, and the amount of CPU utilization. Look closely, as some software packages will open up separate processes for different things it is doing. To find out, open Task Manager before starting your software, and note what processes are running, then see what ones are running after the software is started.
Hard Drives
Hard drives are usually the easiest part of the equation - get the largest you can within reason.
We say within reason, because remember you will have to back it up regularly if you plan to use this as a professional tool. You will be adding tracks, deleting tracks, making changes to them, etc., so if you don't have the capability to back up a couple 400GB drives on a regular basis, don't get them!
Typical MP3 files encoded at 160 -192 kbps, will take up 4-8 MB per track on average, which means you can fit roughly about 180 - 200 tracks per gigabyte of drive space. Just for reference, I took a quick look at one of my drives, and it has 4,565 MP3's, all encoded at 192 kbps or better, and it is using 18 GB of drive space. A few hundred of those are small sound effects tracks, which accounts for the average difference.
Most laptops these days come equipped with a 40 GB drive as standard. If you figured on using roughly 25% of the drive for the operating system and software, page file, etc., that leaves you with about 30 GB of space for your tracks, which averages out to about 6,000 tracks available. More than enough for your average DJ gig.
Spindle speeds of hard drives (5400, 7200, etc.), are not of any great importance to a DJ, unless your files are highly fragmented across the drive. Spindle speeds indicate how fast the drive spins, thereby making a particular place on the drive more likely to be under the read head at any given time. MP3 and other files used for audio are usually of the streaming type, which means the decoder reads them frame by frame in sequential order. Keep your disk defragged, and you will have no issues with the spindle speed of the drive.
Buffer size is another issue which doesn't have much of a major effect in streaming files, although it can be critical to software that uses random access file types, and the operating system itself. You will generally see buffer sizes ranging from 2 - 8 MB these days. Most people will tell you that more is merrier, but that depends on the I/O system, and how it caches within that buffer - a bad caching algorithm can make an 8 MB buffer slower than a 2 MB buffer!
As your library grows, it is easy enough now to add on Firewire and USB external drives, in fact, many DJ's keep their entire library(s) on them, and keep only their software on the internal drive.
Any of the major brands such as IBM, Hitachi, Maxtor, Seagate, Western Digital, etc. are fine drives. You will occasionally see people bashing a certain brand, but as with anything else in life, there are sometimes a bad batch or two that gets through the system. We've used them all over many years, and one doesn't seem any better than the other on average.
Sound Cards (Devices)
We shall refer to sound devices as cards for ease of use here.
A sound card is how music gets from it's digital form on your computer, to it's analog form which you hear on your speakers. When you store music on your computer, it is put into bits and bytes using an Analog to Digital converter (A/D) - when you want to play it back, it goes through the Digital to Analog converter (D/A).
The quality of your sound card is, among other things, one of the deciding factors on how good your sound output to the audience will be. But before going out and buying a $1000 sound card, consider this:
The average noise floor (the ambient noise if you were), at a DJ event, is quite high. People talking, dancing, moving around, etc. So, the difference between a sound card that has a 104 dB signal to noise ratio, vs. 100, becomes not so much of a good factor in determining what sound card to use. We have low end, mid range, and high end equipment to test on, and there's definitely a difference using studio monitors in a quiet room, but no great difference given the noise floor mentioned above.
A good portion of DJ's also run in mono output as well, in order for the music to sound the same at any given point in the room. Add to that, the fact that MP3. OGG, WMA, etc., are lossy formats, and you can see why having the best is not always the best for DJ'ing.
A better judge of a sound card is often the outputs and the driver software that comes with it. A couple points to remember:
-If your software can handle multiple outputs from the same card, you can configure that to better suit your needs as far as the output goes. If your software requires a certain sound card to function properly, that should come as a warning to you, as you may be stuck with a certain manufacturer if you use that DJ software.
-If the driver works reliably, and with most software packages, then you are a step ahead of the game. Before you buy a sound card, check the manufacturers website for updated driver downloads, tech support, etc.
Most of the well known companies produce decent hardware, and keep their driver libraries up to date, such as Sound Blaster (Creative), AudioTrak, M-Audio, etc.
USB and Firewire cards are all the rage of late, for a good reason - they are easy to plug in to almost any computer, and most will actually play using only the Window's XP generic drivers.
If you don't like tweaking hardware and driver settings, use one of the established, well known brands, and you shouldn't have any major problems unless your software is picky.