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Optech; Arbiter

PC Notes
Published April 1994

Brian Heywood delivers another concoction of music‑related PC news.

I went to an interesting press briefing a little while ago; it was given by Motorola on their new PCMedia series of DSPs, which are designed to be used with Windows PCs. The hardware is based on the 56000 range of 24‑bit Digital Signal Processors, which have already found their way onto Turtle Beach products such as the Tahiti and MultiSound cards. DSPs are nothing new in the PC world, so Motorola are also supplying software licensed from various developers, one of which is Peavey — the well known amplifier/instrument maker — and another Qsound Labs, famous for their 3D sound techniques.

The upshot of this is that soundcard developers will be able to plug in features such as Qsound and Peavey's 'software' DPM synthesiser to their new sound hardware. If Motorola are successful in selling the concept to the designers, the quality and functionality of basic MPC soundcards will improve considerably, acquiring features currently only found in professional systems. As Microsoft are planning to incorporate a DSP interface directly into future versions of Windows, the extra features of the Motorola PCMedia components will become available to all MPC applications. As usual, I expect that musicians will benefit from the extra features as music software developers take advantage of the bigger market for high quality audio on the PC.

Optech News

PowerChords, my favourite piece of MIDI software for the PC, is now being distributed by Optech in Farnham. This makes a lot of sense, since Optech already bundle a version of the program with their popular Gravis UltraSound (MPC soundcard). As well as PowerChords (£99) and PowerChords Pro (£199), they are also selling Howling Dog Systems' children's application Dr Drumstix Music Studio (£69). While we're on the subject, Optech have also reduced the price of the UltraSound back down to £149, and it comes with even more bundled software, including a piano tuition program for DOS, the Patchmaker Lite program (mentioned in the February '93 column), Wave Lite from Turtle Beach, and a Roland MT32/LAPC/Sound Canvas emulation program. Existing users can get the 8‑disk upgrade for around £20 from Optech (0252 714340). Optech are also handling the Lyrrus G‑Vox guitar tuition system, which you will be hearing more about in future issues of SOS.

Arbiter Pro MIDI

Richard Fincher has sent me a set of demo disks for products distributed by Arbiter Pro MIDI. The Windows applications covered are Passport's Pro‑4 sequencer, the Encore v3 scoring program, Big Noize's MaxPak sequencing and MIDI utilities, and the Musicator scoring package. The disks should be available from Arbiter Pro MIDI dealers; to find out who your local dealer is, ring Arbiter on 081 202 1199. Arbiter Pro MIDI can also be reached via email on Compuserve, using 100315,46 or via InterNet; the demos are also available for download from the route66/progs topic of CIX.

Card D Revisited

A reader has chided me for being too hard on the CardD system I reviewed in the January '94 edition of SOS. For those of you who didn't read the article in question, the CardD is a stereo sampling card for the PC that has the option of an S/PDIF digital interface. The digital interface lets you transfer the audio to and from your PC and your DAT machine in the digital domain. When used with suitable editing software, the CardD turns your computer into a low‑cost professional hard disk editing system, using the PC's internal disks for storing the sound data. Since you can transfer the information to and from the PC in the 'digital domain', the sound quality is preserved and — as the CardD uses professional‑grade audio converters — you can achieve the much hyped — but not often achieved — 'broadcast quality' sound. I know of a number of studios that use the CardD and get excellent results.

When you compare the performance of a CardD‑based system to more expensive systems, the lack of a DSP becomes noticeable (as mentioned in the review). However, for light to medium usage the CardD is a good choice — in fact, it's the only choice if you want a hard disk system for your PC that costs less than £1500. This lack of performance isn't really the fault of the CardD, but the environment that it operates in and the software that uses it. For instance, the EdDitor software supplied with the review copy of CardD was limited to playing back a single stereo sound file (all the editing is performed 'off‑line'), but Software Audio Workshop (SAW) can mix up to four stereo tracks in real time.

PC Performance Blues

So what's the difference between the EdDitor and SAW software? Well, SAW boosts its performance by making extensive use of 386 32‑bit assembly language programming and by addressing the soundcard hardware directly rather than using the MPC Windows audio drivers. By going straight to the hardware, SAW gains performance at the cost of losing compatibility with most MPC soundcards, so it is limited to a small number of soundcard types, although these are the ones that you are likely to use for serious sound editing.

If you look a little deeper into why the PC is 'too slow', it shows how simply looking at the specifications of a piece of equipment can sometimes give a false impression of how it should perform. For instance, to take disk transfer rates: these are commonly quoted at around 2Mb per second for IDE drives. Unfortunately, this figure doesn't tell the whole story; this is almost certainly the figure for 'burst' mode, and the steady‑state value is likely to be a third to a quarter of this, which is still perfectly adequate for digital audio (which needs less than 200 kilobytes/sec transfer rate) but reduces the number of channels the disk can support. Once the data has been read off the disk the story changes again, since the disk controller and the soundcard are plugged into the PC's expansion bus, which is usually clocked at 5MHz (ie, a 500 kilobytes/sec transfer rate).

However, the data has to be transferred across the ISA bus not once, but twice; once on the 'way in' to the PC, and once on the 'way out' to the soundcard's Digital to Analogue Converter's (DACs). The audio data also has to compete with other data, the most significant being the screen data (250 kilobytes per second of data at a modest screen resolution). All this data has to be filtered through the appropriate Windows drivers, making the ISA bus the M25 of the PC's data highways — inherently fast but overloaded. There are various measures that can improve this — for instance, using a VL bus video card (if you have a VESA slot) or bypassing the Windows drivers (which is what SAW does). So when someone starts quoting specifications at you, make sure you (and they!) understand what the specifications mean within the context that they're being applied.

Price Comparison Of MIDI Interfaces

With so many multi‑port PC interfaces becoming available, I though it might be interesting to see what you get for your money. The graph below is designed to give an indication of the relative costs in terms of output MIDI channels. It should be noted that some units have additional features, such as SMPTE interfaces, which might be considered as a separate portion of the overall cost of the interface. The chart highlights some interesting points — for instance, the MOTU MIDI Express is fairly competitive on a per‑channel basis, despite being the most expensive interface in the list .


  • The number of MIDI outs is shown in square brackets; an 's' indicates that the interface has SMPTE capabilities.
  • These prices are gleaned from various price lists, and so may not be entirely up to date, but should give you an idea of the relative costs.