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RME Hammerfall DSP 9652

Soundcard [Mac & PC]
Published July 2003
By Mark Wherry

RME have added MIDI I/O and extensive DSP facilities to their well-regarded Hammerfall digital soundcard. Will the new Hammerfall DSP keep its place as a benchmark for audio interface design?

RME are one the most respected soundcard manufacturers in the professional audio market, developing a range of products that also encompasses audio converters and, more recently, mic preamps, designed for use primarily with native-based audio workstations. The Hammerfall DSP 9652 (HDSP 9652) is the successor to RME's original Hammerfall PCI card, first reviewed in SOS September 1999, which has become a popular choice for those wanting to integrate DAWs with digital mixers or stand-alone A-D/D-A converters. Indeed, Steinberg sold a rebranded Hammerfall card as the Nuendo 9652 card, and the new HDSP 9652 card is also available from Steinberg under the Nuendo moniker.

RME Hammerfall DSP 9652

Hammerfall DSP technology was first introduced in RME's Hammerfall DSP Cardbus and PCI card products, with the associated Multiface and Digiface breakout boxes, which SOS reviewed as Steinberg's Nuendo Audiolink 96 system in September 2002. However, with the success of the original Hammerfall card, it was only a matter of time before RME would build the Hammerfall DSP technology back into the company's self-contained digital I/O Hammerfall PCI card, and the result — with the addition of some other nice touches — is the HDSP 9652 card.

As an existing Hammerfall user and a fan of RME's technology in general, I was particularly interested to see how RME could possibly have improved on what was already considered by many professionals to be a perfect soundcard.

Feature Perfect

As in the original Hammerfall, the 9652 product number refers to the fact that the card supports sampling rates up to 96kHz and audio inputs and outputs for up to 52 channels — 26 inputs and 26 outputs, from three ADAT I/O pairs and co-axial S/PDIF I/O. Each ADAT channel supports 48kHz/24-bit operation, and S/MUX mode is also available to pair ADAT channels in order to provide 12 96kHz/24-bit channels instead. Like its predecessor, the HDSP 9652 also implements what RME refer to as 'ASIO zero CPU load' technology, meaning that you can have 52-channel operation without placing any burden on the host processor.

RME Hammerfall DSP £399
  • One of the most feature-rich soundcards available for digital I/O.
  • Multi-client ASIO drivers.
  • Advanced monitoring capabilities with Total Mix.
  • Indispensible analysis tools.
  • A headphone output, as on other Hammerfall DSP products, would have been a nice touch.
  • Mac support is lagging behind the developments for Windows.
The existing RME Hammerfall card was close to perfection, but the new Hammerfall DSP still manages to improve on it!


An ADAT 9-pin sync connection is also available for sample-accurate transfers (with a suitable ASIO 2-compliant application, such as Cubase), and BNC word clock I/O connections are still provided. On the subject of clocking, the DSP 9652 card excels at keeping you aware of the clock status of your audio and sync ports via the Sync Check area of the control panel window, and thanks to RME's Intelligent Clock Control technology, the card can automatically sync to the port supplying the most stable clock signal — very handy.

Co-axial S/PDIF I/O is supplied on the same breakout cable as the ADAT 9-pin connection, and you can assign the first pair of ADAT ports to transmit or receive S/PDIF via optical connections instead. As existing Hammerfall users know, it's also possible to set this so the first ADAT output transmits S/PDIF and the first ADAT input still receives ADAT data, or vice versa, which is rather neat.

The original Hammerfall was purely an audio card, but the HDSP 9652 adds two pairs of MIDI ports for 32 MIDI input and output channels via another supplied breakout cable. This is a perfect touch since there are few situations where audio workstations don't require MIDI ports — even if you never use MIDI instruments, hardware control surfaces such as Mackie Control still connect over MIDI.

Although the HDSP 9652 uses one PCI slot in your computer, many of the connections are supplied on a separate expansion card that needs to be fitted in an additional backplate, in the place of another PCI card. And if you find the I/O options of the DSP 9652 not to your liking, a range of analogue and TDIF expansion boards are available separately (see The Hammerfall DSP Family box for more information), and you can fit a second HDSP 9652 card to the same system to double the number of available inputs and outputs. The only extra I/O-related feature I'd perhaps like to see on the HDSP 9652 card is a headphone output, which is present on every other Hammerfall DSP product (see the Family box), even if it just mirrored a digital output pair for test and monitoring situations.

Who's Gonna Drive Your Card?

The HDSP 9652 is compatible with pretty much every major operating system: for Windows users there are multi-client MME drivers, ASIO 2 and GSIF (for Gigastudio) drivers on Windows 98/ME, and full multi-client MME, ASIO and GSIF drivers for Windows 2000/XP users. The multi-client ASIO drivers in this latter set, which RME added during the course of the review, deserves a special mention since they make it possible for two ASIO-compatible applications to be loaded and use the s

ame soundcard and drivers simultaneously, so long as both applications are using different channels. This makes it possible to use Cubase and Wavelab at the same time via ASIO, or even Cubase and Nuendo, for example; and this new multi-client support will have engineers salivating when they see it's now possible to run RME's highly regarded Digicheck analysis software alongside an ASIO application, as described in the Digicheck box below.

Mac users are catered for as well, with ASIO 2 and OMS drivers for Mac OS 9, and Core Audio support under Mac OS X. However, Mac users won't benefit from any multi-client functionality, and, unfortunately, there are no Core MIDI drivers for OS X users to make use of the MIDI ports at present.

 RME Hammerfall DSP 9652For some time, RME have supplied an often-overlooked secret weapon with their soundcards called Digicheck. This is a Windows-only utility based on RME's own DAM1 'Digital Audio Monitor', which provides real-time analysis tools for audio engineers. One of the reasons Digicheck has been overlooked in the past is because, until recently, it only worked as a stand-alone utility and couldn't be used alongside an ASIO host application. But with the release of Digicheck 4 (which was available as a pre-release at the time of writing) and the new ASIO multi-client drivers, you can now use Digicheck to monitor the inputs or outputs alongside an ASIO host application.

Digicheck has many different functions, including Stereo Level Meter, indicating the output of a given stereo pair with both RMS and peak readouts, Multi-Channel Level Meter, showing the levels of eight channels at once, and Global Level Meter, displaying all 26 channels simultaneously. There's also a Spectral Analyser offering 10, 15, 20 or 30 bands, a Vector Audio Scope, with a Goniometer, correlation and peak and RMS displays, and Totalyser, which combines both the Spectral Analyser and Vector Audio Scope in one function. And finally, Digicheck provides a Channel Status Display to show all the Channel Status data included in a digital signal, and Bit Statistics and Noise provides information about the current state of each bit in the digital data stream, and offers DC- and A-weighted analysis. To call Digicheck comprehensive is an understatement.

Digicheck's Vector Audio Scope.Digicheck's Vector Audio Scope.New in Digicheck 4 is Oversampling Mode (OVS), which enables the measurement of signals higher than 0dBFS. This sounds implausible, since levels higher than 0dBFS are actually impossible in the digital domain, but as Matthias Carstens explained to me, it's possible to generate signals that violate the rules of digital audio. The example he gave, which was demonstrated at this year's Frankfurt Musikmesse, concerned the use of digital clipping to get a higher volume on audio CDs: since the majority of tools available don't include advanced filtering when applying hard or brick-wall limiting, heavy digital compression or clipping, the signal won't be bandwidth-limited and will include harmonics beyond the Nyquist frequency. The resulting waveform will be clipped and now represents what Matthias described as a 'violating' waveform.

When OVS is enabled in Digicheck you can see the level the original material had before it was clipped, so I decided to check this out with the 'American Life' track from Madonna's recent album of the same name as a good example of a modern CD release. When OVS was disabled, the peak meters showed the signal peaking at 0dBFS, and with OVS enabled, the peak meters showed the signal peaking at over 2dBFS. Since OVS doesn't change the display of valid digital data, Matthias recommends leaving OVS activated, except when checking final masters for overs when preparing a Red Book-compatible CD.

Digicheck is, quite simply, a brilliant tool that is now utterly indispensable. Thanks to the multi-client drivers, it's perfect for use alongside applications like Cubase SX and Nuendo, which don't include the same detailed real-time analysis tools as standard. Although Digicheck can be used with other RME products than the Hammerfall DSP family, the maths required for the signal analysis is carried out on by the FPGA on the soundcard, reducing the CPU load on the host computer when you run Digicheck on a Hammerfall DSP system.


Hammer To Fall

RME have always been pretty good at supporting their products with driver updates, and the HDSP 9652 card is no exception. During the review, for example, I needed to update the drivers to try out some of the latest features, and in order to use the newer drivers, it was also necessary to update the firmware on the HDSP 9652 card itself. However, I got nothing but errors when I tried to use the firmware update program downloaded from RME's web site, which worried me that the

firmware update process might have damaged the card, or that it was faulty in the first place. Fortunately, the HDSP 9652 card features what RME describe as Secure BIOS Technology, which prevents the card from being damaged if there's a problem when updating the firmware. This works by providing a second, read-only BIOS on the card that's automatically activated if the firmware upgrade fails, enabling you to check your system and redo the flash update.

After emailing RME's Matthias Carstens, my problem was quickly identified. Apparently, the update procedure for the FPGAs (Field-Programmable Gate Arrays) from Xilinx that RME use on the Hammerfall DSP card is incompatible with certain motherboards, and the only solution if the user encounters a problem when updating the firmware is to put the card in another computer. RME are working to improve the situation, and it should be stressed that it's not the HDSP 9652 card itself that's incompatible with certain motherboards, only the firmware update process. Once the firmware has been upgraded, you can move the card back to the first computer and it should work fine.

The motherboard I was using that caused the problems was an Asus AV7M266, a Socket A motherboard featuring an AMD 761 chipset. I tried putting the card in a similar Athlon-based system with an Asus A7S333 motherboard, which has a SiS 745 chipset, and this time the firmware update process worked perfectly. I shouldn't imagine this will be a problem when using the card in a Power Mac, but if you have an incompatible Windows-based system and no additional machine to perform the firmware upgrade, you can send the card to your friendly RME distributor to do it for you.

 The Hammerfall DSP Family 
 If the all-digital nature of the HDSP 9652 card doesn't suit you, RME offer the EXB range of expansion boards, including the AEB4I, AEB8I, AEB4O and AEB8O, which offer four or eight analogue inputs or outputs, and the TEB TDIF board. The HDSP 9652 supports two EXB boards, which connect to the main card via a ribbon cable and require an additional backplate in your computer, with any combination supported, including two of the same type. It's worth emphasising that these expansions don't offer additional channels, though, just alternative ways of getting audio into and out of the soundcard from the ADAT connections.

If the HDSP 9652 still doesn't sound like the card for you, RME's HDSP 9632 might be more appropriate where Total Mix is still desirable, but a smaller number of channels is required. It features a single pair of ADAT I/O ports, co-axial S/PDIF, a balanced stereo analogue input and output, a single pair of MIDI I/O connections, and a headphone output for monitoring that mirrors the other analogue output. Alternatively, there's the forthcoming HDSP MADI, which will be Windows-only initially, offering a pair of MADI connections for 64 inputs and 64 outputs via optical or co-axial connections, with two pairs of MIDI I/O, word clock I/O, and a stereo analogue output for monitoring. While MADI is usually only found on high-end professional equipment, RME have also recently announced the ADI648 converter box, featuring eight pairs of ADAT I/O to a MADI pair. And, finally, there's the original Hammerfall DSP Multiface and Digiface systems as mentioned at the start of the review.


DSP Without DSP

The DSP appendage to the Hammerfall name refers to the card's ability to carry out certain DSP functions such setting up monitor mixes. Oddly, however, it turns out that the HDSP 9652 doesn't actually have any DSP chips on board; instead, RME provide hardware DSP functions using FPGAs, as mentioned earlier.

A Field Programmable Gate Array (FPGA) can be thought of as a reprogrammable processor, where the behaviour of the logic elements can be configured by the designer at any time, even via a downloadable update from the user's computer. So instead of using an off-the-shelf DSP chip or having custom chips manufactured, RME have used an FPGA to provide the specific behaviour required for the DSP functionality the company wants to implement. This means that later, rather than being limited by the fixed behaviour of a DSP chip, RME can simply update the FPGA if its design needs to be changed to accommodate additional functionality.

One of the big questions asked by new users of audio workstations is whether they need an additional mixing console, and while my personal response is always an emphatic 'no', there are certain tasks, such as setting up monitoring, that are often made easier by adding a digital mixer when recording groups of musicians in a studio. However, to overcome the need for an additional mixer for monitoring duties, the Hammerfall DSP series of products all offer Total Mix, which provides complete control over the input, playback and output channels of your workstation.

The second version of Steinberg's ASIO driver API technology introduced a technology called ASIO Direct Monitoring, which allowed the soundcard to route an incoming signal directly to an output, rather than having it pass through the ASIO host application, such as Cubase, and incur a latency that would make it difficult for the musician to play along with the rest of the song. Total Mix basically takes the concept of ASIO Direct Monitoring many steps further by letting the user decide which inputs and playback channels are mixed to which outputs, and all of this happens independently of your ASIO host application, without affecting the way it's set up to record the incoming signals or play back the outgoing signals.

As a simple example of how Total Mix can be useful, say you're recording a guitarist in your live room and you want to give them a different monitor mix to the one you're hearing in the control room. The guitarist's headphones can be connected to a different output pair to the control room, and using Total Mix you can route the input from the guitarist to both monitor mixes on the different output pairs simultaneously. Now, say the guitarist wants to hear more of himself than the playback (for example!), and the engineer wants to hear a balanced level of both the playback and the guitarist — no problem with Total Mix. Simply turn the playback level down on the playback channels routed to the guitarist, and turn the guitarist's input down on the engineer's monitor mix. To finish, the guitarist's mix might be overloading, so you can simply turn the output channels down on that monitor mix.

It's a simple example, I know, and one that's really quite easy when a separate mixer is used with your audio workstation — but that's the point: Total Mix facilitates this type of situation without the user needing a hardware mixer. And as I mentioned before, Total Mix works independently of your ASIO host, so the guitar would still come in on the same input channels at unity gain from your software's perspective, regardless of the routing and levels in Total Mix.

To give you some idea of Total Mix's power, any input and playback channel can be routed to any number of output channels, with each routing having its own independent level setting. This means, to quote the figures on RME's web site, with the 26 input and 26 playback channels being mixed to the 26 output channels, the mixer must be able to do the sums for (26+26) x 26 = 1352 channels simultaneously, which is rather impressive.


As I mentioned at the start of this review, I've been a fan of RME's products and technology for several years now — the attention to detail in every aspect of development is exceptional. Having experienced nothing but rock-solid performance from any audio workstation I've used with an RME soundcard, these products are usually what I recommend if no additional features are required along the lines of Creamware's SCOPE cards, for example. Trust isn't always something you have can have with a product or manufacturer, especially in the technology market, but I trust RME and the HDSP 9652 maintains their tradition of great, yet affordable technology.

infop.gif £399 including VAT.
infot.gif Synthax Audio UK +44 (0)1664 410600.

Test Spec

  • Asus A7S333 motherboard with Athlon XP1800 processor, 1GB DDR (PC2100) memory and an ATi Radeon 7500 64MB dual-head graphics card, running Windows XP Professional.
Published July 2003