You are here

Waves APA 32

DSP Plug-in Host [Mac/PC] By Sam Inglis
Published September 2005

Waves APA 32Photo: Mark Ewing

Waves are the latest software company to launch their own hardware DSP accelerators. The APA 32 and 44-M can be linked over Ethernet to form massively powerful plug-in farms.

At the height of the boom six years ago, the world of music software was gripped by an optimism that seems unimaginable today. With the power of off-the-shelf computers constantly increasing, it seemed only a matter of time before hardware DSP boards and proprietary plug-in protocols became obsolete. Just as Sequential, Yamaha and Roland had come together to create the MIDI standard in the early '80s, so the major software companies would agree on a universal format for native plug-ins. The 21st century would be a golden age of open standards and native processing, where Mac and PC owners could choose whatever software they wanted without having to navigate a minefield of standards and compatibility issues.

Of course, it didn't work out like that. Steinberg, Emagic, MOTU and Cakewalk all ended up supporting different native formats, and the plug-in manufacturers struggled to sell their wares in any of them. Increasingly baroque copy-protection systems failed to curb illegal redistribution, while competition from freeware and shareware developers also threatened the more established companies.

It also became clear that the limitations of host-based processing would not fall away as many people had predicted. Sure, the newest Mac or PC could run hundreds of basic plug-ins, but the realisation was dawning that basic plug-ins didn't always sound very good. Meanwhile, new technologies such as convolution and sample streaming placed further demands on the power of our computers.

Digidesign's decision to stick with DSP acceleration hardware and proprietary standards soon began to look like a good one, and the early years of this century saw other companies follow their lead. TC Electronic turned their attentions from native plug-ins to their own Powercore platform, while Universal Audio's UAD1 PCI card likewise hosted powerful plug-ins that were not available in native formats, and Digi themselves introduced the new HD and Accel systems.

Standing Waves

Throughout all of this, Israeli software developers Waves have retained an impressive commitment to supporting all possible plug-in formats. Virtually all of their many effects and processors are available both in TDM format for Pro Tools systems and in all the major native plug-in formats on both Mac OS and Windows. And although the company have now introduced their own hardware DSP units, it seems clear that they don't intend to abandon development for these other platforms. Rather, it seems that Waves' hardware boxes are designed to complement a native or TDM workstation.

The APA 32 and APA 44-M are, respectively, a 1U rackmounting box and a half-rack-width desktop device. The two models are functionally identical, except that the smaller 44-M is more powerful, and more expensive, than its larger sibling. They connect to the host computer via Ethernet, and can be 'stacked' to create still more powerful systems containing up to eight APAs per computer. Many of Waves' most processor-intensive plug-ins, including the IR1 convolution reverb, can be run on the APA's DSP chips, thus taking the load off your host computer's CPU. However, because there is a system overhead involved in transferring data between a host machine and a DSP accelerator, Waves say that there would be no point in creating APA-hosted versions of plug-ins that don't tax the host CPU very much in any case.

The Naked APA

The review unit we received was the larger APA 32, which is apparently "designed for use in a machine room". The meaning of this sank in when I switched it on for the first time to be greeted by a noise like a Red Arrows flypast. The first unit we were sent was a pre-production model, and I was hoping the production version would be better, but alas there was no difference. The fan noise remains constant while the APA 32 is switched on, and means that you really do need to put some walls between you and it: recording or even mixing in the same room would be out of the question. Fortunately, there are no physical controls on the unit, and the Ethernet protocol allows far longer cable runs than Firewire or USB — the APA 32 ships with a 10m cable, and Waves say they've tested it with a 100m cable. Those without a machine room will have to opt for the more expensive APA 44-M, which is claimed to be almost silent, but was not available for this review.

The APA 32 is solidly constructed, with few external features. The front panel just features a momentary on/off switch, plus a small hole that you can poke a pin in to reset the unit in an emergency. A green LED confirms that it's switched on if the racket hasn't already given the game away. The only sockets accessible from the rear panel are an IEC mains inlet with associated on/off rocker switch, and a single RJ45 socket for connection to a computer. However, if you peek through the metal cage at the back, you can see a bank of connectors that look suspiciously like serial, parallel and USB ports. Taking the lid off the unit confirmed that it is, in essence, a PC based around an ATX-format motherboard, with 512MB RAM and an AMD Sempron CPU. This discovery rather puts the APA 32's £1200 price tag in perspective, and it's disappointing that Waves didn't stretch their component budget to cover some quieter fans.

Where a single APA unit is connected directly to a computer, you need to use a crossed Ethernet cable, which is the type supplied with the unit. If, however, you wish to connect multiple APA units to a single computer, you will need an Ethernet switch (not a hub), and standard non-crossed cables to connect the computer and APA units to the switch. It is also possible to share a group of APAs between several computers, by setting up separate virtual networks for each machine using a managed Ethernet switch that supports the V-LAN protocol. A single Waves plug-in authorisation will cover multiple APAs connected to a single Mac or PC, but every computer you connect will need its own separate authorisation. Each individual APA unit can only work with one computer at a time, but the networking approach allows APAs to be reassigned from one computer to another as needed. Waves recommend that each computer connected to an APA does so using a dedicated Ethernet adapter, but it is possible to hook APAs up to an existing general-purpose network, again by creating a virtual network. Gigabit (1000Mbps) Ethernet is required for all configurations involving an APA 44-M, and for all APA 32 setups except the most basic, where a single computer is directly connected to a single APA 32; this is the one case where you can get away with a 100Mbps connection.Waves APA 32

To Put It In A Netshell...

Initially, Waves are shipping two plug-ins free with the APA 32 and APA 44-M: the new Q-Clone EQ emulator, and a 'light' version of their IR1 convolution reverb. This is a special offer which won't last for ever, but anyone who already owns any of the Waves plug-ins that are APA-compatible can download the new versions without the need to reauthorise them, as long as their existing authorisation covers the latest version 5. The APA-enabled versions have been given the version number 5.2, and v5.2 installers for all of the Waves bundles that include APA-compatible plug-ins are available for download from their site.

Existing Waves users will be familiar with the concept of the Waveshell, a layer of code that sits between the plug-in algorithm itself and your MIDI + Audio sequencer, allowing the sequencer to 'see' the plug-in in a format that it recognises. Likewise, plug-ins loaded onto the APA unit are made accessible in your sequencer by a utility called Netshell. The Netshell itself is totally transparent in operation, but a separate Netshell Monitor application allows you to view the status of each of your APAs.

Netshell Monitor is a small 'always on top' window that indicates the amount of CPU power, memory and network bandwidth available on each connected APA unit. It also allows you to specify the 'round trip' latency that will be incurred by sending data to and from the APA. As with the Powercore and UAD1, the minimum latency achievable is dependent on the buffer size being used by the host application to communicate with your audio interface. In essence, the APA latency must be at least as large as the interface's 'round trip' latency, which equals the audio buffer size doubled. Thus, when you specify a latency for the APA in Netshell Monitor, it helpfully tells you the maximum hardware buffer size compatible with that latency, so that you can change your soundcard settings to suit. The minimum possible APA latency is 256 samples, which requires a hardware buffer size of 128 samples, and equates to a delay of about 6ms at 44.1kHz. In most cases, it should be easy to achieve a latency which is small enough to be accommodated by the host application's plug-in delay compensation feature, if it has one.

The only other feature of Netshell Monitor is a small virtual LED indicating 'Audio Drop-outs'. These can occur if you get your buffer sizes wrong or if there are network problems, but also because it's possible in certain circumstances to overload the APA's CPU. The Netshell is intelligent enough to prevent you from straightforwardly overloading an APA by opening too many plug-ins, but there are circumstances where changing the settings on an already active plug-in can increase its CPU consumption — for instance, by loading a longer IR1 impulse response — and this can push a fully loaded APA over the edge.

Although the APA 32 is based around a standard ATX PC motherboard, the only connection presented on the back panel is an RJ45 Ethernet port.Although the APA 32 is based around a standard ATX PC motherboard, the only connection presented on the back panel is an RJ45 Ethernet port.Photo: Mark Ewing

Getting Installed

I tested the APA 32 on a Centrino laptop running Windows XP, with Waves' Diamond Bundle, IR1 and L3 mastering processor installed. When you run the v5.2 installers, which should be done with the APA connected but not switched on, they begin by uninstalling the previous versions, before replacing them with the new ones. The first one you install configures your network settings as necessary, and adds a shortcut to the Netshell Monitor utility to your desktop. Waves recommend having this utility open whenever you are using an APA.

Initially, I had some problems getting my computer to see the APA. The installers did their job, and claimed to have successfully configured the computer's network settings, but when I launched Netshell Monitor and switched on the APA, I got repeated messages from Windows telling me that a network cable was unplugged, and that the network had no connectivity. I reinstalled the software several times and tried different Ethernet cables, all to no effect, and I was just at the point of giving up and phoning Waves' technical support when it suddenly began to work perfectly for no apparent reason. I never tracked down the cause of the problem, which recurred when I reinstalled the Waves plug-ins a few days later. I did wonder if it might have to do with the fact that my machine is only equipped with 100Mbps rather than Gigabit Ethernet, although this meets Waves' minimum specification.

Once everything was up and running, there's little to say beyond the fact that it worked. I tested the APA with both Pro Tools M-Powered v6.8 and Cubase SX v3.0.2, and encountered no problems in either application. In each case, Netshell-enabled Waves plug-ins show up in the plug-in list twice — the second time, with the word 'Net' appended to the name (which can make for a very long series of nested plug-in menus in Cubase or Nuendo, where all the Waves plug-ins appear under a single submenu). If you choose the first version, the plug-in is instantiated on your host CPU, or on an HD or Accel card in a TDM rig. If you choose the Net version, it's sent off to the APA to be run remotely, and you'll see the CPU and Memory readings in Netshell Monitor change to match. In either case, the plug-in appears to work in exactly the same way. There are no restrictions as to where you can place plug-ins in the signal flow, and it's no problem to have multiple Netshell-enabled processors alternating with host-powered ones within a single mixer channel. Cubase 's Freeze function worked fine with plug-ins running on an APA, too. If you do try to squeeze too much out of your APA, you'll get a polite message telling you that the last plug-in you inserted can't be activated. It's hard to find fault with such a transparent system, though I suppose that Pro Tools users who are used to switching between TDM and RTAS versions of the same plug-in with a single click might wish for a similar feature here.

The Waves site includes a table detailing how many instances of each plug-in type you can expect to get out of each APA unit. I won't reproduce that list here, but my tests broadly confirmed Waves' own findings. They say, for instance, that you can expect to get six instances of the IR1 convolution reverb running on either an APA 32 or an APA 44-M, although which version of IR1 they used is not stated. I found that five stereo-to-stereo instances of the most demanding, IR1 Full Net, with the default Concert Hall preset, took the Netshell Monitor CPU reading to around 95 percent in Pro Tools, and to exactly 100 percent in Cubase SX. All of them appeared to function correctly without dropouts, even this close to the edge. By comparison, five instances of the native IR1 Full took up about 60 percent of my computer's own 2.0GHz Pentium-M CPU, according to Cubase 's VST Performance meter. If those figures are representative, then it would seem fair to say that adding an APA 32 to my system increased the plug-in power available to me by approximately 60 percent — assuming, of course, that I wanted to use that power to run Waves plug-ins. Extrapolating that figure to a network of eight APA 32 units should thus increase the total power of the system by about five times, although with that much network traffic, the load on the host computer itself would be non-trivial. (According to SX 's VST Performance meter, the CPU overhead for a single fully loaded APA 32 was about 5 percent on my PC.)

Compatible Plug-ins

Waves APA 32

The Waves range now encompasses some 50 different plug-ins, most of which are sold in themed collections such as the Restoration Bundle and Masters Bundle. Of those plug-ins, 14 are now available in Netshell-compatible versions for use with an APA 32 or 44-M.

  • The L3 Multimaximizer and Ultramaximizer multi-band mastering limiters were reviewed in August 2005 SOS, and use Waves' proprietary Peak Limiting Mixer technology to increase gain reduction whilst avoiding intermodulation distortion.
  • Waves' IR1 convolution reverb was reviewed in SOS May 2004. The new IR1 v2 can be run on an APA, as can the IR-L 'light' version which is currently being given away with the APAs, and the Mac-only IR360 surround convolution reverb.
  • Q-Clone, the other plug-in presently being bundled with the APAs, also uses convolution technology to 'sample' hardware equalisers. Expect a review in SOS soon.
  • The two most processor-intensive plug-ins in the vintage-themed Renaissance Maxx bundle (reviewed in SOS August 2003), Renaissance Reverb and Renaissance Channel, are both now available in Netshell versions, although it's not possible to route an external side-chain to Renaissance Channel when running on an APA unit.
  • From the Masters Bundle (reviewed in SOS August 2002), Waves' Linear Phase algorithms offer impressive sonic clarity, but have always been CPU-hogs, so fans will be pleased to see that the Linear Phase Equalizer and Linear Phase Multiband processors can both now be hosted on an APA box. The same is true of the powerful C4 multi-band dynamics plug-in.
  • From the Transform Bundle (reviewed SOS December 2004), the Soundshifter real-time pitch shifter and Morphoder vocoder have both been converted to Netshell format, as has the multi-band version of the TransX transient processor.

Summing Up

At first glance, the APA 32 seems pricey when you compare it to the likes of TC's Firewire Powercore or Universal Audio's UAD1. Not only is the hardware itself more expensive, but the APA doesn't ship with plug-ins as standard, so you need to own one of the larger Waves bundles to make it a worthwhile investment. Moreover, the average home-studio user won't be able to exploit high-end features such as the ability to stack multiple APAs on a network. And the APA 32 doesn't just face competition from dedicated DSP processors: given that it is, at heart, little more than a modestly specified PC, some will see better value for money in buying a second computer and networking it via FX Teleport or Logic Node.

However, the point of the APA units becomes clear when you consider what they have to offer Pro Tools TDM users. Here is a device that costs less than a single Accel card, yet offers far more processing power — it's not possible to run IR1 as a TDM plug-in at all, yet even the APA 32 can host at least five instances. The TDM Waves Netshell plug-ins appear in the HTDM plug-in selector menu, so you can use them in Aux and Master busses as well as audio tracks. Many Pro Tools owners have already bought into the Waves range, and the APAs may well represent the most cost-effective way to expand these users' rigs, especially in cases where a PCI expansion chassis would be needed to add more Accel cards.

I like the choice of Ethernet for connecting the APAs, too. Now that many of us are using Firewire audio interfaces and hard drives, the last thing we need is a DSP processor that drains Firewire bandwidth, while the PCI format has its own drawbacks: you can't share or move PCI devices between computers, you can't use them with laptops, and there's always a limited number of PCI slots. The APA can even piggy-back onto an existing network in your studio, if needs be, and long cable runs are no problem. Of course, it would be even more welcome if it supported other people's plug-ins, too, but the Waves range of processors and effects is comprehensive, and the APA hardware allows us to use as many of them as we could possibly want. As usual, Waves haven't been the first company to market with a product of this type, and theirs is not the cheapest, but they've taken the time to get it right.


  • More power than an Accel card, but less expensive.
  • Seamless integration with your recording software.
  • Multiple APA processors can be stacked on a network, and accessed from more than one computer.
  • Ethernet connection permits long cable runs, and doesn't take Firewire bandwidth away from hard drives or audio interfaces.


  • Only bundled with two plug-ins, and that's an introductory special offer.
  • APA 32 is very, very noisy.
  • It's yet another proprietary system that won't run other manufacturers' plug-ins.


If you're already a Waves user and you need more power, the question to ask is not 'Should I buy an APA?' but 'Which APA should I buy?' If you're not, the availability of the APA processors is another good reason to look at the Waves range, although some people will find that other options are more cost-effective.


APA 32 £1199; APA 44-M £1799. Prices include VAT.

Sonic Distribution +44 (0)1525 840400.

+44 (0)1582 843901.