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Buss-powering USB & Firewire Peripherals

Buss-powering USB and Firewire peripherals from a laptop seems like a good idea, cutting down on annoying power supplies and keeping everything portable - but it's not quite as straightforward as you might imagine.

Many musicians buy Firewire audio interfaces with a view to buss-powering them from their PC. This is certainly convenient, saves plugging in yet another wall-wart, and ensures that the interface powers up and down safely with your PC. However, while the 6-pin Firewire ports found on desktop PCs do offer buss power (as do the 6-pin ports on Firewire-to-PCI and PCI Express adaptor cards), unfortunately the 4-pin Firewire ports found on the vast majority of PC laptops don't provide it (one of the few that does is Samsung's X50, which offers a single 6-pin powered port).

Adding three 6-pin Firewire 400 ports to a PC laptop is easy with this PCMCIA adaptor from Belkin, which has its own 12V DC input so that you can either plug in a mains wall-wart PSU or use a battery to provide buss power for Firewire peripherals.Adding three 6-pin Firewire 400 ports to a PC laptop is easy with this PCMCIA adaptor from Belkin, which has its own 12V DC input so that you can either plug in a mains wall-wart PSU or use a battery to provide buss power for Firewire peripherals.

This is indeed frustrating, but is fairly easily explained. Typically, 6-pin Firewire ports in desktop PCs supply 12V DC at up to 15W per port, but looking at my laptop's PSU, it's rated at 65W, so supplying an extra 15W to a Firewire peripheral simply isn't practical — and your laptop battery wouldn't hold out very long when powering such a device, either.

Despite the above, many PC laptop owners point to the 6-pin buss-powered Firewire ports on Apple iBooks and Powerbooks as evidence that buss powering from a laptop can work. However, according to Apple, these Firewire ports only provide up to 7W of peak power when the computer system is on or the power adapter is connected. There seems to be a lot of variation in both voltage and power ratings between buss-powered Firewire ports on both Macs and PCs, so you should be careful not to assume that you can plug any Firewire peripheral into any available port. As long as it requires 7W or less, you should be able to power it from a powered Mac or PC Firewire port, but above this you might suffer reliability problems or find that the peripheral won't boot properly.

Even with the more typical 15W capacity of most PC Firewire ports, many musicians don't realise that you can still overload them. This is a particular problem if you daisy-chain peripherals. Remember that although the Firewire specification theoretically allows up to 63 devices to be daisy-chained from one port, they are still subject to the maximum power drain of that port — and a single 3.5-inch external hard drive can typically consume 12W or more. In fact, so many devices are now being powered from Firewire ports that some PCI-to-Firewire adaptor cards, such as Miglia's Alchemy FW800 PCI, even provide optional connectors that you can plug into standard hard-drive power cables, so you can reduce the card's drain on the PCI buss.

However, in general, if you intend to daisy-chain several Firewire peripherals and buss-power them, do check the total wattage required (there should be a power-consumption rating somewhere on their cases), or use the supplied AC adaptors to reduce power drain on your computer.

Tiny Tips: Keep It Simple

Recently, a PC user reported that after upgrading from Cubase SX2 to SX3, his audio stopped every time he moved his mouse and started again immediately he stopped moving it. The probable cause turned out to be a mouse-pointer utility called Cursor XP, from Stardock (, that lets you create visually attractive mouse cursors. Like Stardock's other products, such as Window Blinds and Window FX, Cursor XP looks wonderful, but as soon as it was switched off the audio problems disappeared. Once again, this reinforces my advice that although it's nice to have a glamorous-looking PC, a stripped-down version is nearly always much more suitable for music production.

PCMCIA-to-Firewire Adaptors

In the quest to run buss-powered peripherals, the next port of call for some PC laptop owners is often to consider buying a 6-pin PCMCIA-to-Firewire adaptor, but this route won't work either, as unfortunately the Cardbus specification doesn't allow such ports to be buss-powered. Fortunately, there is a workaround: some PCMCIA adaptors have a separate connection to another source of power, to enable their Firewire ports to offer buss power.

One such option is Belkin's F5U513ea Firewire Notebook Adaptor (shown above). Widely available for about £30, this unit provides three Firewire 400 ports and a 12V DC input that you can connect either to a suitable wall-wart or to a 12V battery. The latter option is an ideal solution for any laptop musician doing mobile recording: without the additional drain of powering an audio interface, your laptop's battery is likely to last another hour or more.

A slightly different approach that will appeal to those who don't want to use wall-warts is the USB 2.0/Firewire Card from Sweex (, which offers two USB 2.0 ports, plus one 6-pin and one 4-pin IEEE1494a port. The clever twist is that it's bundled with a short mini-jack to PS/2 pass-through connector. The mini-jack plugs into the PCMCIA card, and the other end into your laptop's PS/2 port to provide buss power for the card's 6-pin Firewire port, while the pass-through connector still lets you plug in a PS/2 keyboard or mouse. If you're desperate to avoid using a wall-wart, this might provide the perfect solution, although do bear in mind the total load on your laptop's PSU, especially if you're also attempting to plug in USB 2.0 devices that require their own power. If you're considering battery power for a mobile recording session, don't expect your batteries to last very long, either, especially if your audio interface features high-quality mic preamps.

PC Snippets

Free VST Sampler: Lots of musicians seem to have downloaded the freeware VST Instrument version of Synthfont ( since I mentioned it in PC Notes December 2005. For those who don't necessarily want to use Soundfont sample banks, another more general-purpose VST Instrument sampler to try is Kotkas Soft's Paax 2 Free, which not only imports Soundfonts but also Akai S5000/6000 programs. Written by Mexican developer J Andrés Alvarez, this freeware version is limited to 64-voice polyphony and only plays 8/16-bit WAV files, but Paax 2 Pro has 128-voice polyphony and also supports 24/32-bit samples — and it only costs $29. Both versions have three envelopes and three LFOs per preset, 'micro-granular' pitch-shifting, and built-in reverb, chorus and delay effects. Paax Pro 3, which should also be available by the time you read this, adds a multi-mode resonant filter, advanced time-stretching and pitch-shifting, and direct-from-disk streaming. It costs just $45.

Do you want to trigger samples from a MIDI keyboard, but can't afford a commercial software sampler? Try the freeware Paax 2 Free.Do you want to trigger samples from a MIDI keyboard, but can't afford a commercial software sampler? Try the freeware Paax 2 Free.Keep An Eye On Vista: In PC Notes April 2006, I made some cautious recommendations for musicians who wanted to make sure their new PCs would be suitable for running music software on Microsoft's forthcoming Vista operating system — when it eventually gets released in early 2007. Well, you can now keep abreast of all the latest developments on the official web page, which will not only keep you revved up with tantalising previews but also has a list of detailed hardware requirements with comprehensive footnotes, and even a downloadable beta-version Upgrade Advisor that will tell you what hardware components (if any) you'll need to upgrade to Vista.

Centrance Universal Driver: Centrance have released their Universal Driver for Firewire audio interfaces, after extensive beta-testing. As I mentioned in SOS February 2006, in my feature on using more than one audio interface at the same time, this driver supports multiple interfaces from different manufacturers, and even multiple hosts, so you can combine the I/O from several Firewire interfaces and use them as one across several applications. The Universal Driver supports up to 32 I/O channels on a Firewire 400 port, at sample rates of between 32kHz and 192kHz (24-bit), handles both ASIO and WDM driver formats and costs $79. Apparently it's written at a lower level than many other Firewire drivers and Centrance are confident that it will enable many users to achieve lower latencies than they do with their existing drivers. I haven't yet been able to test it myself, as your audio interface must be on the compatible hardware list and mine isn't. As I write, the current list comprises the Apogee Rosetta; Behringer FCA202; M-Audio Solo; Mackie D2, Onyx 400f and Satellite; Miglia Harmony Audio; Presonus Firepod; and Tapco Link Firewire 4x6. Extra interfaces are likely to be added shortly.

Cubase Compatibility

In SOS April 2005, I wrote a PC Musician feature entitled 'Easier Alternatives To Flagship Music Apps', in which I extolled the virtues of entry-level sequencers and maintained that not everybody needs the very expensive flagship versions of major applications, such as Cubase SX. After all, while the latest version of Cubase SX retails at £499, the SL version is only about £250, while the entry-level SE typically sells at £99, yet still has a huge feature set that is more than sufficient for many musicians.

The freeware SLEX utility will let Cubase SE owners load Cubase SX/SL project files into their sequencer, so that they can legitimately collaborate on projects with SX/SL owners.The freeware SLEX utility will let Cubase SE owners load Cubase SX/SL project files into their sequencer, so that they can legitimately collaborate on projects with SX/SL owners.Steinberg make it easy for musicians to upgrade from SE to SL and SX if they subsequently need the extra features, so I was hoping this article might encourage some musicians to buy entry-level software rather then resort to cracked flagship versions. Indeed, we've subsequently had posts on the SOS Forums from musicians about to buy Cubase SE and SL and wanting to check whether they would still be able to collaborate with friends who already had SX, and from others who have started projects on Cubase SX at college and wanted to continue their work at home by buying their own legitimate copy of Cubase SE.

Steinberg detail the compatibility and the interchangeability of project files in their Knowledgebase (http://knowledgebase.steinberg.d...), but unfortunately, while Cubase SX3 and SL 3 will read each other's project files, you can't open these files in Cubase SE 3. Or, at least, not without a tweak discovered by David Dorn, an enterprising SE3 user trying to help a bunch of students. He examined the difference between the project files, which amounts to a single letter: one contains the words 'Cubase SX' and the other 'Cubase SE' near the end of each file, and if you change the 'X' to 'E' you can load the SX files into Cubase SE3.

Of course, SE3 will ignore any SX3-specific content it finds in a project file, and you have to be careful not to exceed the SE limits for plug-in sends, inserts and VST Instruments, otherwise SE might crash (which is probably why Steinberg made these tweaks in the first place). However, everything should otherwise work fine, enabling lots more musicians to officially buy into the Cubase range.

David has since written a stand-alone SLEX utility, to turn any SX/SL project file into an 'SE-friendly' version. The utility is now available for free download from, and it ought not to infringe any copyrights, since it simply modifies your own project files — after all, this seems no different from the multitude of word-processing applications that offer import and export functions for documents created in Microsoft's Word, Corel's Word Perfect, and similar programs.

SLEX comes with no guarantees, of course, and if your PC crashes as a result of using it, that's nothing at all to do with Steinberg. However, I personally feel that the utility ought to be not only tolerated but accepted by Steinberg, since it should ensure plenty more legitimate owners of Cubase SE3, who may later on upgrade to the SL or SX versions. In the meantime, SLEX lets them work within the limitations of their entry-level version of Cubase, safe in the knowledge that they can transfer their work to Cubase SX, and back again, if and when they need to.