Ralf Schluenzen with the PowerCore card.
Paul White meets the head of TC Works to preview the company's new PowerCore card, a DSP engine designed to relieve host‑based MIDI + audio sequencers of some of the strain of running processor‑intensive plug‑ins.
These days, computer‑based recording and processing environments come in two types. On the one hand, we have systems like Cubase VST, which run host‑based plug‑ins from within a friendly, sequencer‑like working environment. On the other hand, we have external DSP‑based systems such as Digidesign's Pro Tools, which run high‑powered, DSP‑hungry plug‑ins in a different environment. The DSP‑based approach provides us with more power and expandability, and often there's good integration with the major sequencer manufacturers, but it is generally impossible to freely combine VST effects and DSP‑hosted plug‑ins within the same virtual mixing environment. What the world really needs is some kind of DSP card that will allow us to run more, bigger and better VST format plug‑ins without having to forever upgrade our computers, but apparently that isn't technically practical. However, TC Works have developed something they call the PowerCore DSP card to host plug‑ins that can be used freely within a VST environment, which is probably as close to the ideal as we're likely to get. I met with Ralf Schluenzen, the head of TC Works, to ask what made their approach so different to that of their competitors, and to find out why they thought their card was necessary...
Explaining PowerCore
Modern computers are really very powerful now, and getting faster every few months, so why do we need help from a DSP card? My current Mac G4 can run lots of virtual instruments and plug‑ins, and it's not even a dual‑processor model.
"It is good that computers are becoming more powerful — after all, this is the reason that host‑based audio recording became possible in the first place! However, user expectations are rising exponentially — they need more tracks, demand a better sample rate and bit depth, would like to use virtual instruments — and last but not least, they demand more and better processing! A computer is designed as a general‑purpose machine, not with audio in mind, so while it can do audio processing perfectly well, it doesn't always do it efficiently. Efficient audio processing requires a lot of little 'special' details, and a DSP card that uses DSPs specifically designed for audio processing has significant performance advantages when compared to a computer. By using our PowerCore PCI card, you can still use your computer to run virtual effects and instruments as before, but it will allow you to run more high‑end signal processing — such as serious reverb — at the same time."
Does it have audio I/O so that we don't use up another PCI slot fitting an audio card, or is it purely for processing?
"No, PowerCore does not offer audio I/O because it is not a hard disk recording card. It has been specifically designed as a number‑cruncher — a DSP Turbo if you like. Our concept is to allow the user to decide what their front‑end software and I/O hardware should be and to work alongside that. Users don't need an alternative I/O card — there are so many great solutions already like the MOTU 2408, Midiman Delta, RME Hammerfall or the Digi 001."
We've had DSP cards for years that can run plug‑ins — what makes yours different?
"What we found out from users is that they'd like to have the ability to use high‑end plug‑in processing, like our TC Tools, or Waves C4 or whatever, from within their familiar native environment and still be able to run a sensible number of tracks and other effects at the same time. Predictably, this is where the host‑based system still lacks something. Imagine the situation: a producer records a song, say a moderate 30‑track production with a lot of vocals and some 'real' instruments. Then he decides he'd like to use a vocoder in addition to his reverbs and other effects, only to find out he no longer can play all his tracks because his performance meter is clipping. This is clearly no good for a pro setup, and frustrating to any user! That's where PowerCore comes in — it supplies the user with the power to run demanding high‑end processing, yet it completely integrates with any VST‑compatible system. It works with whatever audio interface the host software supports, and it can also work with the Mac's internal sound system, if the user so wishes. This means any version of Cubase, Logic, Peak or Spark, and also the forthcoming Nuendo for Mac, will work with PowerCore right away. No special versions of the host software are required, so there's no waiting for new releases or updates."
Compatibility
Will PowerCore work with all VST‑compatible programs, or only software from manufacturers who cooperate with you?
"In the first instance, PowerCore will only work on the Mac platform, with PC support projected for the end of 2001. Other than that, any application that loads VST‑plug‑ins is compatible right away without the host software designers having to do anything. I really don't believe in closed systems; I feel that today's users demand and deserve fewer proprietary interfaces and more standards. VST is such a standard, and we would like to help elevate the platform even further into the higher‑end sector of the market. With PowerCore, the user gets the best of both worlds: the flexibility of VST plus the power and reliability of a DSP‑based system.
"There's one thing I want to come clean about straight away, though, as we don't want to create the wrong impression : VST always introduces some degree of latency when recording through plug‑in effects, due to the fact that the signal passes through the computer's operating system. As PowerCore lives transparently in the VST world, we can't change this. If your latency performance is acceptable using host‑based VST plug‑ins, then it should be fine with PowerCore, but if your VST system's latency is high, PowerCore won't improve it. Of course, this source of latency only affects the user when trying to record through a plug‑in. When mixing or mastering with effects, any latency is compensated for by the host software, so the user doesn't feel it at all."
So, I've got a load of existing VST plug‑ins, I've got a VST‑compatible application — can I just plug PowerCore in and start using it? Or am I getting ahead of myself?
"The signal processing on PowerCore is carried out by Motorola DSPs, not by the host processor, so we can't run the same code as host‑based VST plug‑ins — the DSP code needs to be written specifically for the Motorola DSPs used on the PowerCore card. Conceptually, the idea of an audio equivalent of a graphics accelerator is appealing, but it's currently not possible in the VST environment. Host‑based processing requires a completely different technical solution from DSP‑based processing. So there has to be a new plug‑in format, which we call PowerCore VST. This differentiates it from host‑based VST, but also underlines the fact that you can load PowerCore plug‑ins into any VST sequencer that has a PowerCore card fitted. And even though they're in this new format, PowerCore VST plug‑ins behave exactly like normal VST plug‑ins. You can move them anywhere in your signal chain, you can place them in line with ordinary host‑powered VST plug‑ins without restrictions, and they show up in the same folder as your other VST plug‑ins. The difference is that the signal processing is carried out on the PowerCore's DSPs, not the host computer, so you don't use up the host's performance resources. That's the main point — unlike in some other systems, you aren't limited to using either host‑based or DSP‑based processing. You can use them both at the same time, from within the familiar VST environment, giving you an unprecedented degree of flexibility."
If you can't run VST plug‑ins directly, couldn't you create a shell program, like you did in Spark, to allow your card to run them?
"This is an appealing idea, but not easy to do. If we say a conventional shell program is comparable to having a continental adaptor for a UK plug, in the case of PowerCore this would be equivalent to simulating the power plant and the whole electric wiring system as well! VST plug‑ins have to be 32‑bit floating point algorithms so that they can run on a PC or Mac. Plug‑ins written to run on audio DSPs, such as our existing plug‑ins for Pro Tools and now PowerCore, need to be 24 or 48‑bit fixed‑point algorithms. They are very different implementations; it's not just a simple translation task."
So where do users get the special PowerCore plug‑ins that will run on your card?
"For starters, we are including a PowerCore version of our TC Tools package with the card, comprising MegaReverb, TC EQSat and TC Chorus/Delay. Normally, this software alone would cost around two‑thirds of the price of the software/card bundle. High‑end reverb — such as MegaReverb, which is of similar quality to the TC M2000 hardware reverb — places a serious drain on host‑based processing sources, so it makes sense to provide this for the DSP card. Our other high‑end plug‑in packs, VoiceTools and MasterX, will also be available separately when the card is released.
"More important is the fact that PowerCore is completely open to third‑party developers, not only on the application and audio card side, but also to other plug‑in developers. This is done with a view to establishing an open platform that completely integrates with VST in the first instance, and may be extended to other formats in the future. We have already started talking to the key plug‑in developers, but at this early stage it wouldn't be appropriate to drop any names. Users don't benefit from promises, they benefit from results."
Power Issues
To put PowerCore into context, how much more power will it give me than that from an ordinary fast computer?
"There are many myths and misconceptions about computer speed measured in Gigaflops and such‑like; for audio applications these figures can be misleading. Both Mac G4s and Intel PIIIs are running a general‑purpose OS — they are not optimised for handling audio tasks. Though they are undeniably powerful, their general‑purpose nature results in less efficiency. For example, on a Motorola DSP you can perform a 'multiply‑add' — a multiplication and addition together — and two memory accesses, all at the same time, in a guaranteed response time of one to two processor cycles. By comparison, on a Power PC or Pentium III, a multiply‑add requires three to four cycles, depending on the processor model. And the speed of memory accesses heavily depends on the computer's current cache state, very often taking up to 20 cycles to do the same task. This, of course, minimises the available horsepower on G4s or PIIIs quite dramatically, so a 56K DSP running at an apparently modest 100MHz easily equals or even surpasses the signal processing capabilities of a general‑purpose processor like the G4 or PIII.
"To give you an example of what that means in practice, when designing the host‑based high‑end SurroundReverb for Nuendo, we ported parts of our reverb technology over from code written for DSP‑based systems, which enabled us to do direct benchmarking on different systems. MegaReverb requires roughly 50 percent of the performance of one DSP on the third‑party platform it currently supports, 35 to 40 percent on a G4/500, and around 35 percent on one PowerCore DSP! The bottom line is that just one of our 100MHz DSPs offers about the same audio processing capability as one G4/500 processor. And there are four of those DSPs on our card, plus an additional Power PC chip. So, if we continue this process of comparing apples and pears, you could say that in the context of audio processing, you get roughly the power of four Mac G4s on our card. That's a lot of power available for running high‑end plug‑ins."
Does the card need special drivers?
"The card comes with its own drivers, but they can't be compared to an audio card's drivers — you don't even have to reboot after you install them."
Will it be possible to run two or more PowerCore cards for even more power?
"Well, we are a bit conservative with statements that rely on theory rather than practical experience. Let's just say the design was conceived to allow for this, but we won't be able to really evaluate this before January. What's more, most Mac users won't have more than one free PCI slot, so the design goal was to provide as much power on one card as practically possible."
Does PowerCore support 24/96 operation?
"Of course! And even higher sample rates if you want. Naturally that would reduce the available bandwidth — the higher you go, the fewer plug‑ins you can run at the same time. But this is not a soundcard, so there are no converters or other items that get outdated quickly."
Will the card also run virtual synths?
"Again, we don't promise things that haven't materialised yet. For greatest compatibility, PowerCore's interface to the VST world is based on the VST 1.0 spec for now, and that doesn't have the MIDI features required for synths — that's part of VST 2.0. Right now, we are committed to delivering an open, high‑end effects platform with a lot of additional potential for future development. Even though we do have long‑term plans for PowerCore, we don't want to promote the system on the basis of unimplemented future developments, because 'potential' doesn't do anything for a current purchaser. The decision on whether or not to buy the card should be made based on what it does on release, not on what we may add in the future."
Will the plug‑ins be copy‑protected?
"That's a very important point: the card offers a system‑unique copy‑protection system, that is one which is keyed to individual PowerCore cards. It's hardware‑based, so there will be no more dongles on the back of your computer! The TC Tools plug‑ins that come with the card won't require any additional copy‑protection procedure, while for optional plug‑ins, TC Works or the third‑party developer will issue a response to a challenge, which will then authorise the plug‑in to run on the system. This degree of security may encourage developers to release more high‑end plug‑ins as PowerCore VST versions, whereas they may be reluctant to produce standard VST high‑end plug‑ins because of the prevalence of plug‑in piracy."
Availability
When is PowerCore due to be released?
"I wish it was now, as I want one myself! In reality, the release is targeted for the end of March 2001, and we will probably do a tour in the UK in February to ensure that our dealers have all the information they need to service our customers.
How much will the system cost?
"Our target UK price is £999, which is quite attractive considering you get a copy of TC Tools 96K and the equivalent power of four G4s. Given the quality of the reverb algorithms, and the fact that it will be possible to open several instances of the reverb plug‑in at the same time, I feel it's probably worth the cost for this alone."
Paul White meets the head of TC Works to preview the company's new PowerCore card, a DSP engine designed to relieve host‑based MIDI + audio sequencers of some of the strain of running processor‑intensive plug‑ins.