Solving Akai Sampler SCSI & CD-ROM Compatibility Problems

Using a sampler without some sort of hard drive is just not an option these days, which means that some understanding of SCSI is necessary. Devoted Akai samplist Paul Farrer explains some of the pitfalls that can befall the unwary user of SCSI'd up samplers, and examines some of the other cross‑platform issues that can complicate sampling.

There was a time when a sampler could get everything it needed to know from a floppy disk, both in terms of samples and operating system software. Samples weren't particularly complex or memory‑hungry in those days, which was just as well, because samplers themselves had only a limited amount of RAM and seriously basic editing facilities. The advent of the first affordable stereo sampler, however, changed all that: sounds increased in quality and therefore complexity, samples became bigger, and as a result storage capacity had to be much, much greater. No longer could you cram everything onto two or even five floppy disks — piano samples these days are considered average if they'll fit into 8Mb. Clearly something had to develop, and fast. Enter the strange sockets round the back of your sampler; the ones that bear the mysterious inscription 'SCSI'...

Terminator Too

The world of music technology is riddled with more strange acronyms than most of us care to remember, and just as we all know that SMPTE is pronounced simp‑tee or sim‑tee and not S.M.P.T.E, so it is with SCSI (Small Computer Serial Interface), which is pronounced skuzzy. SCSI is used for connecting computer peripherals, such as samplers, hard drives and so on, and the connection is in the form of a chain, not unlike MIDI. Most stand‑alone hard drives (CD‑ROMs, magneto optical drives and so on) have two SCSI connectors and you can chain devices together by using the second connector, rather as you would the Thru socket in a MIDI setup.

Because of the speed of data transmission along a SCSI cable, it is vitally important that both the first and last device in the SCSI chain are terminated, to prevent data corruption caused by signals reflecting back from the end of the line. All Akai samplers are internally terminated, and as they only have one SCSI connection, they obviously have to be at the start (or the end) of the chain. From here you can connect and go through as many as seven other devices, but it is essential that the last device is terminated. Any hard drives or other devices in the middle of the chain should be un‑terminated, and you can check in the documentation that came with your hard drive to see whether it is normally terminated or not. Many hard drives these days give you the option to terminate or un‑terminate via DIP switches, and some even automatically terminate themselves if they detect that only one SCSI connector is plugged in. If there is no built‑in means of termination, you can buy stand‑alone SCSI termination blocks which simply plug into the spare socket on the last unit in the chain.

Each device within the chain has to be allocated a different SCSI ID number between zero and seven: no two devices can share the same ID or the system won't work. To use another MIDI analogy, it might help to think of them as a number of monophonic synthesizers that all have to have a separate MIDI channel number. In the case of modern Akai samplers, the CPU (Central Processing Unit) defaults to a local ID number of six, and on boot‑up, as a matter of course, it starts looking for a hard drive resident on ID number five. If you want to change these ID numbers, you can, and if you're working with more than one sampler, you may find you have to (see below).

Most hard drives have a small switch on the back (and in some cases a series of DIP switches) which allows you to specify the ID number. For your sampler to address an external hard drive, the SCSI ID you set in the sampler must match that of the drive you are looking to load from or save to. This works fine for a simple setup of a single sampler and hard drive combination, but if you have more than one Akai sampler and a couple of hard drives in a chain, you have to allocate your ID numbers with care to avoid conflicts.

When you switch your sampler on, it searches for its operating system, first in the built‑in EPROM, then in the SCSI chain, and finally in the floppy drive. This means that if two or more devices boot up in a SCSI chain all thinking they have the same local ID number, you are in for trouble. The best way to solve this problem is to first assign each sampler a different local ID number (on Akai S3000 series machines you can find this in the SCSI Drive Control Page by hitting Load then F5); once you've done this, allocate a drive number for it to look for on boot‑up, then re‑save your operating system onto a spare floppy disk which you can keep permanently engaged in the sampler's disk drive. If you follow the same procedure for each sampler in the chain and make a note of which device is on which ID number, you shouldn't have too many problems (see Figure 1 for a typical SCSI chain).

Cores And Effect

The new generation of Akai samplers (the S3000XL series and the MPC3000) uses 25‑pin 'D'‑type SCSI connectors, but older units (such as the S950, S1000 and S2800) have the larger 50‑pin Centronics connectors. This is also true of many hard drives and CD‑ROMs, and Akai say that there is no difference in quality and reliability between the two systems. To connect a 25‑pin sampler to a 50‑pin CD‑ROM drive, you simply need the correct converter cable with the appropriate plug on each end, or a converter socket, but what is vitally important is the type and quality of the SCSI cables you use. While some computer systems seem happy to work with virtually any SCSI cable, Akai samplers in particular seem to be rather fickle about what they will and won't work with. If you have a cable that your sampler doesn't like, you may get errors while trying to load samples, or you may find that the drive you're attempting to connect is not recognised at all.

There are two main types of cable: the moulded cable and the flat ribbon cable. Ribbon cables are principally designed for use within computer devices and don't need to be as robust as external cabling. Moulded cables, on the other hand, are the thick round sort that have stronger plugs and can much better withstand repeated plugging and unplugging. By its very nature, SCSI requires that each conductor in the cable is individually screened, but some manufacturers make cables with only a single ground for all the connections. As stated earlier, your PC or Mac might be happy with this, but your sampler may not be so forgiving. Remember that all the SCSI devices in your chain are effectively connected on the same circuit, so if just one of your cables is a rogue, the chances are that it will screw up operations throughout the whole chain.

With this in mind, ribbon cables, which run alternately signal and grounded wires across the cable width, are often more reliable (providing they don't have to be moved about too much), but it's worth noting that this kind of cable doesn't have external screening, so it's best to keep them away from other cables to prevent interference getting in or out.

When I was asking around for SCSI stories for this article, SOS's own Martin Walker was very helpful in raising a number of points, one of them being that buying all your cables from a single manufacturer (although this is not always easy if your studio expands over the course of a few years) sometimes helps maintain uniform impedance, and therefore minimises the mismatches and reflections that cause SCSI errors. One further point to keep in mind is that the SCSI specification states that the total length of all the cables and devices in your chain must not be greater than six metres. That's not to say, though, that if you have SCSI problems, just swapping cables around within your setup won't solve them. Editor Paul White reports frequent SCSI problems with his S2000, which are always solved by changing SCSI leads, sometimes back to the ones that were there last time it failed! The order in which external devices are connected also seems to make a difference.

My own setup works perfectly providing I have specific cables in specific places in the chain. If I remove cables or swap them around (even keeping the same SCSI chain order) I run into problems. To sum up, the simple rule of thumb seems to be that, just as with any other connectors in your studio setup, it hardly ever pays to cut corners and buy the cheapest cables you can. Insist that the spec of the cables you buy features Individually Screened Cores; this is important to find out beforehand, as it's generally impossible to tell what kind of moulded cables you have bought just by looking at them!

Compatibility

If you abide by all of these wiring guidelines and are very careful with your choice of cabling, why is it that you can still get problems? One opinion that I seem to hear quite a lot from Akai users is that older machines such as the S1000 and S1100 tend to be tolerant of a much wider range of cables and drives than the newer units — an observation perhaps compounded by the fact that it would seem Iomega Zip drives (one common Akai stablemate) are not all the same and are said to contain slight differences in the firmware that is shipped with each unit. Though this can hardly be blamed on Akai, it is apparently not uncommon to buy a brand new Akai and Zip drive combination only to find that it blankly refuses to work, leaving everyone scratching their head.

Another potential fly in the ointment is that the ever‑increasing speed of more modern external CD‑ROM drives could actually exceed what your Akai sampler can handle, and may prevent their use altogether. Unfortunately, it seems that there is no easy or immediate solution to this problem; so far the only sensible advice seems to be to try before you buy. The last thing any music shop wants is hoards of angry customers knocking at the door demanding refunds, and many stores will now only recommend drive, cable and sampler combinations that they know to be reliable. If this isn't the case, I don't think it is too much to ask that they spend 20 minutes taking you step by step through the best way to set up your SCSI system (including the cables) in the shop, before you part with the readies.

Format Capacity

Owners of Akai S900s and S950s will undoubtedly be aware that the IB109 SCSI interface fitted on their machines will only recognise and work with a maximum of 60Mb of hard drive space. The MPC60 can also only recognise 60Mb, but the newer MPC3000 and 2000 modules have been considerably upgraded to work with up to 739Mb. From the S1000 sampler onwards (including the S1100, S2800, S3000, S3200, S2000, S3000XL and S3200XL), Akai fitted their samplers with the much larger hard‑drive capacity of 512Mb, but many users might still find half‑a‑Gig capability somewhat limiting. If you think back to the days when the first S1000 modules came out, most hard drives were between 40 and 80Mb and the thought of a Gigabyte hard drive for under £300 was still the stuff of games designers' wildest dreams — Akai obviously felt at the time that the 512Mb limit would be enough.

These days, of course, all that has changed, — the way that the computer peripherals market is going, I'm sure it won't be too long before they're giving 120Gb hard drives away free with breakfast cereal — but many Akai users are left with the prospect of only being able to use hard drives no bigger than 512Mb. Akai have maintained this limit on their current range of samplers to permit retrospective compatibility with older machines, and in the majority of cases, 512Mb capacity should still be adequate.

For those of you thinking of using a Gb hard drive with an S‑series sampler, hoping that it will work happily using only half the storage capacity, I'm afraid you'll probably find it's not that simple. Akai seriously advise against this, claiming that although it might sound like a good idea in theory, in practice the nature of the way Akai data is stored to disk means that you may well run into some defragmenting access problems. Or, to put it in more friendly muso‑speak: it won't necessarily work! If, therefore, you are an Akai user and you want to create the ultimate 15Gb archive of your sound library, what should you do?

Well, at the moment you essentially have just two options, if you discount backing up to DAT: get a removable drive (such as the Iomega Zip, or Syquest EZ Flyer 230), or use Akai's own Mac‑based sample editor/librarian MESA to create a library of sounds stored on your computer's hard drive. Although it's currently available only for the Mac, Akai tell me that a PC freeware version is soon to be posted on their web site. However, the PC version of MESA has been promised for so long now that I can distinctly smell frying bacon mingling with aviation spirit! [Pigs might fly, in other words — Simultaneous Translating Ed] Also it's possible that Akai may be releasing a newer operating system (as a floppy disk update) when the PC version of MESA comes out — this has been hinted at by AL Digital, who are part of the development team. This may also improve the Akai's SCSI reliability a little, but only time will tell.

Sample CD‑Roms

When other sampler manufactures claim that their machines are Akai‑compatible, they usually mean that their machines will address, acknowledge and load S1000‑formatted data via SCSI (with the possible exception of the Kurzweil K2000, which will also load S3000 format samples). The S1000, probably because it was one of the first truly affordable stereo samplers to establish itself as an industry standard, quickly became the most popular format for sample CD‑ROM producers. Of course, the S‑series has come a long way since then, and so have the amount and complexity of the data saved to disk by a modern sampler. Manufacturers such as Emu, Roland and Kurzweil each have their own distinctive ways of dealing with the basic blocks of recorded sample data, and, naturally, different sample architectures all have their own unique terminology — which is usually the biggest headache for any samplist looking to hop between machines on a regular basis. For instance, what Akai refer to as Programs, Emu call Presets and while some users like to edit a Sample, others might be more used to truncating a Tone.

As far as the end user is concerned, the current glasnost between rival sampler manufacturers can only be a good thing, mainly because it allows much more open access to other manufacturers' sound libraries. For the most part, sample CD‑ROM manufacturers have opted to stick with producing discs using the S1000 format as a sort of common denominator. Not to say that the S1000 is the principal instrument used in the creation of these sound libraries (in fact in most cases it's not used at all), rather that most sample CD‑ROMs are edited and processed entirely in the digital domain, before being burnt onto the master in an S1000‑friendly way.

The current range of Akai S‑series samplers (plus the MPC2000/3000) also supports both Roland and Emu sound libraries via SCSI, and importing sounds in this way is, generally speaking, a glitch‑free and straightforward exercise. You might occasionally get minor anomalies — drum kits that load up with the portamento switched on, or filter settings turned down to a minimum — but for the most part you should get positive results. If in doubt, ask your sample CD‑ROM supplier, as they will probably be aware of any cross‑compatibility problems relating to specific discs. Discs that don't present samples and programs in the way you might expect often have sleeve notes with specific instructions, so do read these before proceeding.

Thanks to Ed Morris from Akai Technical, Jason Creasy from Time and Space, and Martin Walker.