by Sergey Samarin
04/11/2003 | 11:32 PM
We guess there is no one around here who thinks the progress in the IT field is too slow. But the rapid development of high technologies creates certain problems for us (when it comes to making an upgrade) as well as for manufacturers because they have to update their production equipment. It’s now not just difficult to keep pace with the fashion, but downright costly. Moreover, it is one thing when you spend your hard-earned money on an ultra-mega-super-copper processor, which immediately tells on the overall system performance, and quite another thing when you purchase a questionable pleasure of improving the sound part of your PC.
In fact, while the future of CPUs is quite clear (just take a look at the roadmaps of the few manufacturers), it is very hard to guess which way the sound cards development will take. In the last ten-twelve years audio cards have developed from simple one-octave four-bit wheezers into complex multi-channel devices featuring their own signal processors. It may seem today that the sound cards have reached the utmost of their potential, but it is only the tip of the iceberg that we see. More discoveries lie ahead.
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Once upon a time there was IC Ensemble Company, which came into being in 1998. In the next year already, the company rolled out its multi-channel audio-controller aka ICE 1712 Envy24 that immediately found its way into many professional Value sound cards (like Hoontech ST Audio DSP 24, Midiman Audiophile 2496, TerraTec EWX 24/96 and others). Collaboration of VIA and IC Ensemble yielded VIA’s new product series featuring integrated up-to-date audio technologies – they showcased VT82C686A South Bridge at CeBit ’99. After the ensuing success, it became clear that VIA had some plans for IC Ensemble. This came true in November 2000 when VIA bought that company up. As a result, VIA acquired a daughter company specializing in development of top-end signal audio processors and mixed semiconductors and also made a claim to be “pushing up PC sound quality level”. The Envy24 trademark became the banner of VIA’s camp. Moreover, VIA chose the right marketing policy in PC sound solutions area and made this trademark popular in the SOHO market. We might say that VIA, formerly unknown in the audio cards marketplace, won this “shooting competition”.
Last year the company released new improved versions of the Envy24 audio-controller. The first variant, Envy24HT, was intended for PCI audio cards, the second, Envy24PT, for integration into mainboards. It should be mentioned that ICE 1724, which from now on will be marked as VT1724 (hereinafter we will refer to this chip as VT1724), differs very slightly from ICE 1712: you can’t find any differences in the flowcharts of the two controllers. The main innovations are the support of eight-channel systems and ability to work in 192kHz / 24-bit mode.
Soon after the Envy24HT announcement, two companies expressed their desire to use it in their products. They were TerraTec and M-Audio (formerly known as Midiman). The both are well known as manufacturers of top-end audio cards and have successfully co-operated with VIA. Today we are going to review the major of audio card series from TerraTec – Aureon 7.1 Space, which was announced in the end of 2002.
TerraTec has long grown from a local German company producing audio cards into one of the leading European manufacturers of various multimedia products. Still, the production of top-end audio cards and development of accompanying technologies, like EWS Technology and 4G Sound, remain the priority field of TerraTec activities. Some time ago, the company turned to the consumer multimedia sector and released audio cards targeted at the mass user.
TerraTec Aureon 7.1 Space
TerraTec SoundSystem Aureon 7.1 Space comes with:
Aureon 7.1 Space from the German TerraTec Company belongs to the new generation of eight-channel audio cards. This audio card allows digital recording with 24bit / 96kHz and playback with 24bit / 192kHz parameters at a low signal-to-noise ratio (-100dB). The card’s hardware components are all excellently chosen and provide a professional quality of sound. Here are the main features of Aureon 7.1 Space:
Minimum system requirements
The PCB of Aureon 7.1 Space is made of dark glass-cloth laminate. Its dimensions are nearly identical to DMX 6fire and 1.5cm shorter than Audigy. The gold-plated back bracket carries six mini-jack and two optical connectors. There are also two 10-pin connectors on the board that might seem to be intended for extension modules. But the manufacturer doesn’t offer any daughter-cards for Aureon and these connectors serve purely technological purposes. In fact, the official documentation is scarce in describing technical nuances (for example, it doesn’t even tell that Aureon is based on Envy24HT! Quite a shame!), so we decided to explore the hardware part of Aureon more closely.
The heart of Aureon 7.1 Space is a multi-channel audio-controller aka VIA Envy24HT (formerly known as ICE1724) supporting twelve input and twelve output channels (ten of them are analog and two more are digital). The chip has a powerful integrated digital mixer of a high resolution (considering the processing of 20 channels).
Besides purely musical capabilities (MIDI and GPIO support), the controller supports a joystick game port, which seems to be a legacy feature (manufacturers prefer USB for their new game manipulators). Moreover, VT1724 is responsible for communication with the PCI bus.
The controller flowchart available on VIA’s website is too simplified and doesn’t tell of any new units integrated into the Envy24HT architecture. Moreover, this flowchart resembles very much the flowchart of ICE 1712 controller IC Ensemble has been producing since 1999 (when no one ever heard of “audio solutions from VIA” :)). By the way, you can find more detailed info on Envy24HT at VIA Technologies' website.
Envy24 ICE 1712 Detailed Block Diagram
The effect-processor functions are entrusted to the digital 96kHz audio-interface receiver from Cirrus Logic: CS8415A-CS. This chip receives and decodes one of the seven audio channels according to appropriate interface standards (SPDIF, AES3 and so on).
Cirrus Logic: CS8415A-CS Block Diagram
The flowchart shows that there is a multiplexer at the input of the device. It collects data from seven audio channels one by one. Thus, the receiver processes data from one of the channels chosen by the multiplexer during one clock cycle; then they are sent over for further processing. Extra audio effects can be added to the sound data at this processing stage. CS8415A is used not only in audio cards, but also in AVR, CD-R, DAT, DVD and MD devices.
The VT1724 audio controller works in pair with a high-performance eight-channel audio-codec WM8770IFT from Wolfson. This chip supports all external analog ins and outs of the card (there is a twofold operational amplifier of the 4580 series before each analog output). Here are some basic parameters of WM8770IFT:
8-channel WM8770IFT audio codec
with analogue volume control
WM8770IFT audio codec block diagram
Four stereo 24bit DACs are used with digital interpolation filters that perform sampling with a reserve of sampling frequency (so-called oversampling). They support digital audio input with 16-32bit capacity and 8-192kHz sampling frequency. Every digital channel allows independent volume control; the set of input multiplexers allows sampling from three external analog inputs.
The codec’s audio interface supports I2S and DSP data format. It is controlled via a three-wire serial interface, including channels selection, volume control, elimination of high-frequency constituents (de-emphasis) and power supply control.
The use of such a powerful codec as WM8770IFT in a SOHO-level audio card indicates that the requirements to modern home multimedia devices have grown up. Interestingly, these chips are also used in hi-fi auto radio-recorders and audio-visual systems.
The world of digital electronics stands on three foundations: microprocessors, memory and logic. Microprocessors execute program instructions to perform a variety of tasks, memory chips store various information, while logic devices serve as an interface between these two components. Aureon 7.1 Space uses a XC9536XL chip from Xilinx as such complex programmable logic device. This device is equipped with Fast Flash memory controlled by an integrated programmable controller. The micro program is flashed into the chip at the manufacturing stage, so very close to this chip there is a special 10-pin connector marked “System Port” on the back side of the PCB.
Just a few years ago such a chip cost about $150 and worked at up to 40MHz frequencies. Now technological advances have reduced the prime cost to $10, while the frequencies have grown to 400MHz. A curious fact: CPLD-chips were often used in military onboard computers, but now you can find them in cell phones, navigation systems and audio cards called Aureon.
One more codec, SigmaTel STAC9744T, supports the internal AUX analog audio input. This codec series is out of production now (“Not available for new designs”, to be exact, which is the same thing, actually).
The flowchart of the codec is shown above. At the hardware level STAC9744T supports the following sampling frequencies: 48kHz, 44.1kHz, 22.05kHz, 16kHz, 11.025kHz and 8kHz. Other frequencies are available through the audio driver. The digital interface of the codec communicates with the AC’97 codec via AC-Link. STAC9744 is rather an old solution and was mostly intended for dual-channel audio support, so in Aureon it fulfills some secondary fucntions. Interestingly, this codec was used in some audio cards to reproduce Dolby Digital streams. Several such codecs would make up a multi-channel solution, sometimes a four-channel codec (9704/07/21/23) was used among them.
Besides the above-described chips, Aureon has some simple logic chips. They are Philips 74HC4052D and Philips 74HC125D. The first one is a high-speed doubled four-channel analog multiplexer/demultiplexer, the latter – a chain of four logical “AND” elements. In fact, the 74th logic series is the most “long-living” generation of semiconductors and has been produced since late 80-s (these chips have survived a few PC generations).
Every package of every sound card from TerraTec carries a 4G Sound logo: a red ear with a “hear the truth” slogan. 4G Sound is the name of a surround-sound technology: 4th Generation of Sound (for PC). The sound cards generations changed in 1998 right after first low-cost audio controllers capable of reproducing 24/96 sound appeared. If you would like to find out more about the application field for such high-resolution audio solutions, refer to the articles (in PDF format) at TerraTec’s website:
TerraTec audio cards for the multimedia market support the Sensaura technology developed by a company with the same name. The company has been engaged for over twelve years into writing math1ematical modeling algorithms for sound environment. Sensaura-supporting audio cards are easily recognizable for the logo on their packages.
Here is the list of Sensaura functions:
Now, let’s dwell on each of the mentioned functions in detail.
Sensaura MultiDrive. This subset of the Sensaura technology allows 3D sound playback with the help of the standard API DirectSound 3D. A special algorithm, Transaural Cross-Talk Cancellation (TCC) was developed for this purpose. TCC is better than standard CC algorithms at producing low-frequency sound. The user is able to control TCC and adjust its work mode. MultiDrive is intended to work with Sensaura’s MacroFX and ZoomFX algorithms.
Sensaura MacroFX. This algorithm solves the problem of authentic sound reproduction immediately close to the user. It produces the effect as if the sound source had been moved from the loudspeakers to the listener’s head, or even got inside the head! This weird thing is achieved by means of an accurate modeling of the sound wave in the 3D environment around the user’s head. The modeling algorithm adjusts volume differences and takes into account time delays occurring when the ears perceive sound from a single source (ITD – Interaural Time Delay).
Sensaura Digital Ear. This method is based on a math1ematical model of the human ear with changeable parameters (“there are no two men with identical ears”). The concept of the math1ematical model implies that complex resonance and diffraction effects, which are an inherent part of any HRTF-function, can change independently. As a result, a duplex system was developed that helps to adjust various parameters in an arbitrary scale.
You can install Sensaura 3D demo programs from the installation CD that comes with Aureon, and listen to those 3D sound effects.
The software from TerraTec is not that rich in various utilities as the Creative package coming with Audigy2, for example (see our Creative Audigy 2 Platinum Sound Card Review). You will only have to install from the included CD a driver and Aureon Control panel where you adjust settings not present in the standard channel mixer. The Control panel itself is divided into six functional sections.
Here you set the volume level for each of the eight speakers. It’s also possible to turn any of them off completely. These sliders do volume control and channel balance very discretely (you can easily perceive the stepping by the ear).
In this section the user sets different volume levels for sound sources and balances them with the faders. Interestingly, if you turn any of the playback sources off with the Mute button, it can still be used for recording (of course, if it’s selected in the Record panel).
This window allows choosing a recording source. The Mix button allows recording signals from all analog sources simultaneously, mixing them up depending on the recording level set for each source.
This window keeps the settings for digital in- and output. Sampling frequency is usually adjusted automatically by the running application. Aureon doesn’t allow “locking” a selected frequency (unlike DMX 6fire, for example).
From the Digital window, you can go to setting the size of the ASIO buffer.
This window serves to configure the loudspeaker system. By the way, when you choose headphones, you hear quite clearly a click of the relay that turns on the preamplifier. This relay is placed on the PCB next to the line front-end output.
Here you can also activate the Sensaura mode, but this requires system re-boot.
This window contains info about the installed driver and Control panel versions as well as about the operation system and DirectX.
If you do not speak English, choose your favorite way of communication in the language menu.
Besides other things, you can select another color palette, if the default doesn’t look nice to you.
The driver, Control panel and electronic documentation sit on the CD next to the following software:
There is also a dozen of shareware demo programs on the CD. They are third-party software, so we won’t discuss them here.
Creative Labs usually rolls out a new loudspeaker system for each new audio card. TerraTec, on the contrary, set its eight-channel Aureon 7.1 Space into a free sail. There is just no multimedia loudspeaker system of the 7.1 format in the market. They simply have not been made yet. Manufacturers involved are still thinking and watching sales results of the new generation audio cards. So, if everything goes right, we will surely see acoustic systems like that pretty soon. And it even depends on ourselves: if we buy these powerful sound cards really well, they will roll out eight-channel loudspeaker systems ASAP :).
In fact, the eight channels are only used to create theater-like environment when watching DVD movies. Computer games need no more than six-, or even five-channel systems. It’s the same George Lucas who’s stirring up trouble. Moreover, there is some intriguing info around that this guy has already made up a twelve-channel prototype (the 10.2 format!) in his country house. They don’t say anything definite about its getting into mass production, but we wouldn’t be surprised to meet such a system at the premier of the next “Star Wars” episode. So, the 7.1 format may turn out to have a shorter lifecycle than the 5.1. Actually, the paradox of this situation lies with the fact that the audio sources of the musical picture could be separated with the math1ematical modeling algorithms and not by simple increase in the number of active channels. But sound positioning algorithms are hard to develop and it usually takes quite a bit of time. Moreover, manufacturing companies are better off making and selling new loudspeaker systems.
One way or another, we had to test Aureon 7.1 Space and we chose Megaworks 510D and Creative Inspire 6700 systems. When listening to stereo music files, you turn on the Sensaura mode to engage the rear acoustic channels. This mode also should be on if you want to enjoy surround effects in games supporting A3D or EAX. But you’d better not use it when watching DVD movies. When activated, Sensaura notably increases the subwoofer volume level. To adjust the settings to your taste, use Aureon Control panel rather than the subwoofer control itself. The balance between the front and rear satellites is adjusted with Control panel fader, which is represented as a sphere.
We would like to point out a good implementation of audio effects in games. We had a demo program from Audigy2 left. We ran it with Aureon and were pleased to find out that TerraTec’s card correctly reproduces absolutely all EAX surround effects.
This six-channel sound card is a solution for a sophisitcated user who has to work with top-end sound processing programs. This card can work with 24bit/96kHz parameters, is compatible with all standard API of surround effects and suits well for reproducing 3D audio effects in computer games. DMX 6fire supports DirectSound 3D as well as A3D, EAX and Sensaura. TerraTec says DMX 6fire is based on the EWX/EWS88 technology thus providing high sound quality at over 100dB SNR. The card comes with a commutation unit to be installed into a 5”-bay of the chassis (just like the Creative Audigy Drive from the Platinum set). This unit allows easy connection of various external audio devices (analog and digital devices, MIDI-peripherals, headphones, microphone and so on).
The following software comes with the card: Cyberlink 6-channel PowerDVD, Algorithmix Sound Laundry TerraTec Edition, Steinberg WaveLab Lite Ver.2.0, Musicmatch Jukebox, Emagic MicroLogic FUN.
The Control Panel is divided into four sections containing groups of related settings.
In the Mixer section you can adjust signal amplification levels; current values are shown in decibels (0.1dB discrete step). Here the audio source for recording is also selected.
The type of the speaker system is set in the Surround section. Here you also set volume levels for the satellites and subwoofer and enable the Sensaura mode.
On enabling Sensaura, the user can use the fader to adjust sound sources panning. Note also that when you activate Sensaura 3D, the digital mode settings in the Settings window of the Control Panel become inactive.
This section mostly contains digital output settings. From this window you can go to advanced driver properties and set the card up for work in professional audio applications (ASIO/GSIF).
The About section provides information about the version of the installed driver, operation system and DirectX. With the only exception of the advanced ASIO panel, the DMX 6fire Control Panel is nearly identical to that of Aureon 7.1 Space.
The PCB of DMX 6fire, just like that of Aureon, is made of black glass-cloth textolite.
The card is based on a multi-channel audio controller Envy24 (ICE1712) that can work with top-end I2S converters, S/PDIF-transmitters and audio codecs. The controller itself features an integrated digital high-resolution mixer that can process up to 20 channels. The audio controller also communicates with the PCI bus and performs audio streams routing. ICE1712 works in pair with a digital audio transmitter from Cirrus Logic aka CS8427, operating with up to 96kHz sampling frequencies and 24 bit capacity. Its dynamic range is 106dB. An AC’97 codec, based on AK4524 chip from AKM Semiconductor, sends the sound to analog outputs. Low-noise operational amplifiers are placed right before the analog sockets.
If we are not mistaken, we saw the ICE1712 and CS8427 bunch as well as codecs from AKM, in professional Hoontech ST Audio DSP 24 card, with only one difference: the transmitter functions were distributed there between two chips from the same Cirrus Logic (CS8427 was also used in professional Echo MIA cards). On the hardware level DMX 6fire resembles TerraTec EWX 24/96. But having put so much excellent stuff into DMX 6fire, TerraTec somehow didn’t care to implement virtual audio channels in the driver, as we can see in most professional sound cards. At the same time, multi-client functions for simultaneous work with several audio applications are all there. So, we were puzzled with the actual market target of this sound card: is it intended for professional use or for amateurs? We guess the feature this card boasts are still not enough to solve professional tasks properly, while for gaming applications the features are even more than enough.
DMX 6fire carries three connectors for extension modules. The cable of the commutation module from the shipment package connects to one of them. The module covered with a solid metal case has only interface elements, and no additional codecs.
At the front panel of the module there are MIDI-input and output ports, two digital optical connectors, two coaxial connectors, 6.3mm microphone and headphones jacks and three pairs of analog RCA connectors for independent audio sources. Above the headphones and microphone jacks, there are volume controls. There is also an overload indicator. Three more LEDs above optical, coaxial and analog connectors light up when the corresponding connectors are selected in the Control Panel.
We used the following testbed configuration:
As we have already said above, Aureon 7.1 Space is based on the improved version of the audio controller (Envy24HT), so we decided to compare Aureon with DMX 6fire audio card based on ICE1712 Envy24. Unlike Creative cards, which have been developed for the multimedia market from the very beginning, the above-mentioned cards from TerraTec went down to us from the professional audio cards niche. We include Audigy2 test results here, too, so you will be able to compare Aureon with Audigy2 (click here for our detailed review of Audigy2). For our tests we used SpectraLAB software suite (v.4.32.17), which consists of two parts: a signal generator and analytical-measuring part. Before the tests, we turned off all the audio surround effects that might bring distortion into the output signal.
To find the value of signal/noise ratio (SNR), total harmonic distortion (THD) and intermodulation distortions (IMD), the software signal generator emitted tone signals of a certain shape. They were 1kHz signal for SNR and THD and the standard set of two low and high frequency tones (LF = 250Hz, HF = 8020Hz) for IMD.
The SNR is the ratio of the useful signal level (here, it's 1kHz signal) to the noise level in all frequencies of the spectrum. The higher is the SNR, the better. The calculations are performed by the analytical part of the test program, displaying the results in real time.
The THD is the ratio of the harmonic capacity to the fundamental capacity. THD is calculated by seeking the peak frequency in the spectrum (and the base). The overall capacity in separate frequency harmonics is determined relative to it. The overall noise level is not counted in calculations (it’s used in the THD+N parameter). Lower value of this parameter (in percents) indicates better sound purity. THD is always calculated with the 1kHz reference signal.
The intermodulation distortions (IMD) parameter shows the percent of distortions when two tones are mixed together. The typical IMD calculation is done with 250Hz and 8020Hz tone signals with the high frequency tone fading to the low frequency one by 12dB (4:1 ratio). In order to prevent random noises from interfering with the results, the IMD is calculated after a series of tests.
TerraTec Aureon 7.1 Space spectrograms
44,100Hz / 16bit
Determining IMD at 44,100Hz / 16bit
48,000Hz / 16bit
Determining IMD at 48,000Hz / 16bit
TerraTec DMX 6fire spectrograms
44,100Hz / 16bit
Determining IMD at 44,100Hz / 16bit
48,000Hz / 16bit
Determining IMD at 48,000Hz / 16bit
The results are listed in the table:
TerraTec Aureon 7.1 Space
TerraTec DMX 6fire
44,100Hz / 16bit
48,000Hz / 16bit
44,100Hz / 16bit
48,000Hz / 16bit
44,100Hz / 16bit
48,000Hz / 16bit
The results prove that Aureon 7.1 Space is a very high class product, which surpassed Audigy2 in all tests and was just a little worse than the more expensive DMX 6fire. Aureon produces very pure sound, with the noise level below -100dB mark. The low percent value of THD suggests that there are no significant harmonics peaks. All this is clearly seen in the spectrograms. Of course, such minute advantages are not perceptible by ear and we won’t contend that Aureon is indisputably better than Audigy2. There are also such factors as functional software where Audigy2 beats its opponent. Moreover, both sound cards are targeted at the mass user who doesn’t demand as much from the product as a man who is professionally into music.
When perceived by the ear, Aureon 7.1 Space did very well reproducing life-like timbres and pure sound. High-quality speaker systems provided a necessary stereo-panorama width in an ordinary-sized room. Together with the fundamental basses this allowed us to enjoy excellent and precise sound sources positioning and their stable perception at any volume level. Actually, you can adjust anything with the mixer, but we didn’t feel any discomfort at all, so it was mostly playing with the feature just for fun.
One problem we had with Aureon 7.1 Space was that the card refused to give out any sound in some gaming applications, especially after Sensaura was enabled. The problem was solved by installing up-dated drivers from the technical support page (it was 5.1.2600.11 driver dated 10.02.03). That’s about all.
Our tests show that Aureon 7.1 Space can become a worthy opponent to popular audio cards from Creative. At least, it may be an appropriate solution for the user who wants to buy a card without an additional commutation unit. We guess there is no reason to buy an eight-channel card now just because of this extra channel, hoping to buy an eight-speaker system in the future. But it makes sense to purchase Aureon as a high-quality and affordable audio card with the bonus of the eighth channel. Most of us don’t buy a sound card to enjoy the movie-house effects when watching DVD. Listening to music on the PC and having sound effects in games are the most demanded things.
In Europe the card is now selling for the retail price of 149 Euro (around $160).
In fact, we guess that we are approaching the time when multimedia PCI audio cards become the thing of the past and leave the slot in the chassis for specialized professional sound solutions. And this time is going to come as soon as the VIA Envy24PT audio controller, coming to us from the world of professional audio, gets integrated into mainboards.
TerraTec DMX 6fire audio card can be viewed as a rival (or alternative) to Creative Audigy Platinum with Live! Drive commutation module, but it proves much better than Audigy in playback and recording quality as well as in multi-client functions support. This card doesn’t support (yet?) EAX 3.0 and so doesn’t aspire for a slot in the system of a hardcore gamer. Besides, such features as IR-port and wireless remote control available by Audigy should add some points to Creative’s card in the view of a mass user.
Anyway, we are quite certain about one thing: TerraTec DMX 6fire is a worthy alternative to Creative Platinum.