PC Plus Soundcard

Brian Heywood considers the role of affordable 'PC plus soundcard'‑based digital audio recording systems, and considers whether such systems could ever mean the end of dedicated hard disk recorders...

The last few months has seen an increasing number of MPC (or Multimedia PC)‑based hard disk recording systems becoming available. Cubasis Audio, Cakewalk, TripleDAT and the like all provide a level of functionality that is beginning to encroach on the domain of the high‑end professional systems. Some might argue that this is just a continuation of a current trend (namely that computer‑based technology tends to provide better features for less outlay as time goes by); but there are numerous advantages in a Windows‑based digital audio system comprising a soundcard plus the appropriate application, especially when you consider 'integrated' MIDI and audio applications like the audio versions of Cubasis or Cakewalk.

However, there are a few issues that need to be considered before deciding to use a MPC‑based non‑linear audio system. Most soundcards on the market claim that they produce 'CD‑quality sound' — but this simply means that they happen to have a pair of 16‑bit digital‑to‑analogue converters (DACs) on board. Unless the circuitry around the DAC is well designed, you'll find that the least significant bits don't actually do anything, effectively reducing the 16‑bit DAC to 15 or 14‑bit resolution, or even lower. Even if the digital‑to‑analogue circuitry is well designed, there are other factors, such as noise generated by the PC's power supply and RFI (Radio Frequency Interference) from adjacent cards inside the PC that can worsen the signal‑to‑noise ratio. Most professional systems place their converters outside the PC, the only exception being SADiE, which virtually isolates the on‑board converters by total enclosure in a metal shield.

One solution is to get a soundcard with an S/PDIF connection (like the CardD+ or the TripleDAT) which solves any potential 'quality' problems the same way as the 'professional' systems do (if the signal remains digital all the way through the PC to the output, it can't be affected by PC power supply noise or RFI) — but you do need to have a decent DAT machine to take full advantage of this route.

Usability

With an MPC‑based system, the features and usability are usually dependent on how powerful your PC is — to take an example, consider Cubasis Audio, reviewed in last month's SOS. Cubasis Audio illustrates the advantages of integrating MIDI and audio; it is entirely dependent on the MPC facilities of Windows for both its MIDI and digital audio playback. As the article pointed out, it comes with a performance tester that showed that the reviewer's PC could play back four mono tracks. When I ran this utility on two of my machines, it reported the number of available audio tracks as one (on a 486DX/50) and two (on a 486DX4/100). I assume the inferior performance on the faster machine was due to the fact that it was only fitted with 8Mb of RAM. So, to get either of these systems to give performance comparable even to that of a fairly modest 4‑track cassette multitracker, I'd need to spend at least £200 for an extra 8Mb of RAM. Add that to the cost of the software (£250) and then maybe an extra hard disk for the audio (540Mb at £130) and an audio mixer (£120 or more), and you've more than doubled the cost of your 'low‑cost' PC‑based recording system.

So the moral is — watch out for any hidden costs. Use the following checklist to see if a particular system suits your needs.

• Is your PC powerful enough for your intended use?
• Do you need extra RAM?
• Is your soundcard quality good enough?
• Can you sync the digital audio to your existing sequencer?
• Do you need to buy a mixer to get the sound into your PC?
• How fast is the editing process?
• Do you need to master down onto DAT?

When you add the costs of the extras you need to buy to get a system working to your specifications, you may find that it actually works out cheaper to buy a dedicated hard disk recorder like a Soundscape SSHDR1 or Digidesign Session 8!

Lyrrus G‑Vox Revisited

I've had a lot of fun recently playing around with both the Roland GI‑10 and new Lyrrus G‑Vox guitar MIDI systems. Paul White covered the Roland unit in depth in the June issue of SOS, so I won't go over old ground, apart from saying that it works very well and is a very worthwhile investment for the studio‑based producer/guitarist. However, if you fancy a more computer‑based approach, Lyrrus's new low‑profile version of their guitar pickup is also worth a closer look. Unlike the previous version, which mounted on 'suckers' over the strings, the new model is slim enough to fit under the strings of most guitars (the pickup is curved to keep the distance between the pickup elements and strings constant). The pickup can be attached to the guitar using the supplied suckers, or fixed permanently using double‑sided tape.

The pickup connects to a belt pack which in turn connects to the serial port on the PC. The belt pack contains a DSP that does the pitch‑to‑note conversion, so there's no extra load on the PC's CPU. The DSP code is downloaded from the PC, allowing the software to be updated at any time. The G‑Vox system comes supplied with a number of DOS‑based applications, and Lyrrus can supply DOS‑based tuition software specific to their pickup.

More interesting is the Bridge software, a MIDI device driver for Windows, which allows you to connect the pickup to any Windows‑based MIDI application. The Bridge not only allows you to play your guitar into any program — say a sequencer — but also allows you to alter the performance characteristics of the G‑Vox system, and even tune your guitar. You can also assign each string and/or range of frets to different MIDI channels, so you can control multiple MIDI instruments. Unfortunately, the Bridge doesn't implement pitch bend yet, but this is planned for future releases.

Like pitch‑to‑MIDI units, the Lyrrus hardware suffers from the delay caused by the time it takes the DSP to calculate the pitch of the note you've just played. This delay is dependant on the pitch of the note, and can't be any less than half a wavelength for physical reasons. However, the Bridge device driver uses an interesting piece of lateral thinking and a feature of the Windows MIDI API to improve the performance. The DSP in the belt pack can accurately determine where the start of the note is — it just takes it a while to work out the pitch. So it records the true start time of each note and then, once it has determined what the pitch is, it has the Windows device driver send the note message to the MIDI application with the actual note start time, rather than the time that it worked out the pitch. Though this means that the driver is effectively lying to the MIDI application, it does ensure that when the MIDI is played back, it is an accurate transcription of the performance.

One thing to be aware of if you plan to permanently attach the pickup to your guitar is that the cable that connects it to the belt pack can't be unplugged from the pickup, which might make it awkward to use the guitar in any sort of live performance situation. At just over £350, the G‑Vox is a somewhat less expensive solution than the Roland, but is unusual in that Lyrrus charge for the Windows device driver, which adds another £116 to the package — although you may get a discount if you buy both items at the same time. Ring Koch Media (01252 714340) to find out where to get a G‑Vox for your guitar.

Roll Your Own Backing Band...

Of course, you don't have to plug your guitar into your PC to create music from scratch — you can also use it to support your other musical activities, such as practising and learning new material. One program I find especially useful for this is Band‑in‑a‑Box (BiaB) from Canadian company PG Music Inc. Like Jammer (mentioned in August's PC Notes), BiaB is auto‑accompaniment software, which means that you can quickly set up an arrangement in a particular style (say Jazz, Bossa or Rock), and leave the software to sort out what each instrument plays. Unlike Jammer, however (which is really designed to help create original music or arrangements), BiaB is very simple to use, and allows you get an arrangement up and running with the minimum of effort on your part, allowing you to concentrate on making music rather than the PC technicalities.

I have recently upgraded my copy to version 6.0, which adds a number of useful new features, including better support for entering melodies, a standard notation window and the ability to print out the music in standard 'lead sheet' format. Unfortunately, there is no way of entering the melodies by hand on a music stave — you have to either play the melody in via MIDI or import it as a MIDI file from another application, which can be a bit fiddly. But you'll be surprised how quickly your performance skills can improve when you start playing regularly with a band — even if it's a silicon one! It's really quite uncanny; the 'software' musicians in the program are so realistic that they've never been known to buy a round!

...Or Hire A Virtual Session Guitarist

Another interesting program from PG Music is Jazz Guitarist, which is a sort of musical workshop covering a large number of well‑known jazz standards. The music was created by a Canadian jazz session player, Oliver Gannon, using a MIDI guitar to give an accurate 'live' feel to the music. The software not only plays the music via MIDI, but also shows the fingering and notation as it plays, allowing you to really get inside the music. Each piece has a short description with performance notes and musical anecdotes. While the choice of material is rather limited to older standards, it can still give an insight into the way jazz guitarists voice their chords and interpret melody lines. Both PG packages are available from Arbiter Pro MIDI (0181 202 1199). Band‑in‑a‑Box costs £89 and Jazz Guitarist £49 (prices include VAT), which makes them ideal Christmas stocking fillers.