TerraTec 6fire DMX vs.
Creative Audigy Platinum eX

Until this event we had the Creative's Audigy Platinum eX as a multimedia leader. At the end of the last year the Platinum eX got the "iXBT.com/Digit-Life 2001 Award" as the best multimedia sound card of the year.

Today we are going to watch a hot fight of two heavy-weights of the sub-$250 category. In several minutes we will take a look at competition of multimedia sound cards of the Hi-End class.

In this duel we have two products which arrived into the same market sector from two different worlds.

• Audigy Platinum eX is a feature-laden multimedia-gaming card designed for semiprofessional use. The heart of the card is a hardware EMU10K2 processor with samples and sound streams into RAM of the computer.
• DMX 6fire 24/96 is a sound card based on professional technologies and adapted for multimedia needs. The card uses a professional Envy24 controller and AKM codecs. Taking into account all latest achievements in the processor development, all capabilities are realized on the drivers level. 

For details on the Audigy Platinum eX see this review. Today we will speak mostly on the new 6fire card, but in comparison with the last year's champion.

Here is how TerraTec divides sound cards into generations:

• 1981. Palaeozoic. MS DOS and 5" diskettes. First computers from IBM equipped with a 1-bit PC speaker. The epoch of Covox and Scream Trackers.
• 1988. Stone Age. The epoch of first SoundBlasters and their multiple clones. A simple FM synthesizer Yamaha OPL2 and a digital channel working in the 8bit 11.25kHz mode.
• Mid-90s. Middle Ages. Windows 3.11 and 95. Multimedia PCs. Pseudo CD-quality everywhere, which provided only 16 bit 44.1 kHz playback. 
• Our time. Industrial Age. High-quality converters in sound cards. The 24/96 format in professional and home studios. 

 

• 1997. Renaissance. AC'97 standard. A3D->DirectSound3D->EAX->Sensaura. A generation of sound cards with a PCI bus, a controller and a codec are mounted separately. Vortex1/2, Live!/Live!5.1, CS4630, AC'97 sound integrated into mainboards. 

What for are 24 bits 96 kHz?

• Presentation 4G 
• 24 bit/ 96kHz-Technologie 

 

First of all, converters supporting 24/96 have a newer design and a higher price. That is why they record and play sound noticeably better in all modes, including good old 16 bits 44 kHz (games, CD, MP3) and 16 bits 48 kHz (DVD).

Secondly, 24/96 will be useful in sampling audio records with further processing. Then it's possible to make downsampling to 16/44, but it's always better to sample with some reserve. It's like in the photo world. If you need a high-quality photo of 640x480 you know quite well which device should be used for digital photo shooting: a web camera of the same low resolution or an expensive digital camera which has some reserve in resolution and quality. In the latter case it's not difficult to process and reduce the image to the required parameters, but the result will certainly differ although the final parameters are identical.

By the way, all inexpensive DACs supporting 24/96 have better characteristics exactly in the 16/44 mode. It's connected with operation of 1-bit converters with oversampling and filtering. That is why it's not enough to teach a DAC to receive data in this format and then announce the 24/96 support to make this format worthwhile given the output sound quality reached.

On the other hand, the mass industry has just started moving toward the formats of extended precision of data representation. And in the currently dormant sphere of high-quality sound new ideas and new formats become a banner of marketing crusades of hardware makers pursuing users' wallets. Be careful, my friends. Well-known Asian makers of Hi-End devices for PCs at $10 are wide awake. :)

Unfortunately, a digital data storage format and quality of conversion of these data into an electric signal and then into an acoustic one are not identical concepts. Most drivers of modern sound cards allow playing the 24/96 mode. Or rather, they do not have its playback forbidden.

And now let's take a look at new formats of extended precision of data storage offered by the industry of Hi-Fi and mass consumer electronic equipment.

CD-DA vs. DVD-Audio

But now, when an elemental base of the microelectronics has gone far ahead in quality and quantity (cheap data storage media now house more information, the mechanical and digital parts allow for a higher read and processing speed), DVDs with movies and home theater equipment become very popular (5.1-channel acoustic sets and multichannel amplifiers with an integrated decoder and an effect-processor).

So, now it's possible to change the beloved but compromise 16bit 44.1kHz PCM stereo format for something more advantageous. Current discs with movies based on the DVD-Video standard are not up-to-date as well. Although they are very popular now, the standard limited bitrate makes us choose between sound quality and image quality. Certainly, image is more important a priori, that is why sound is stored mostly in a multichannel format with compression or in PCM. In the latter case two fixed sampling frequencies are available - 48 kHz and 96 kHz. At 48 kHz it's possible to record multichannel sound, at 96 kHz - only stereo. Data bit capacity can be 16, 20 or 24 bits.

The limitation is connected with the bitrate of the DVD-Video standard which makes 6.1 Mbit/s for an audio track. The bitrate is 4.4 Mbit/s for the maximum audio modes. However, it's pleasant that the DVD-Video standard gave rise to mass production of DACs supporting 24/96.

Two years later after the DVD-Video's birth, in 1998, the first specification of the DVD-Audio was ratified by request of the audio industry. The following two years were spent for development of a copyright protection system. The discs appeared just in 2000.

DVD-Audio can be compatible with DVD-Video (it depends on a manufacturer) and can have several tracks for choice - high-quality stereo or multichannel ones with compression and losses. But data of higher sampling are kept in a separate disc area (in AUDIO_TS folder), that is why they can't be read by usual DVD-Video players. It's necessary to have a special player supporting DVD-Audio.

The maximum possible parameters of audio data storage in a format without compression (PCM) for stereo are 24 bits 192 kHz, for multichannel track: 3 main channels (left and right front, plus center) - 24 bits 96 kHz, 2 rear channels - 24 bits 48 kHz. A one-layer disc without additional features enabled takes 64 minutes. The DVD-Audio uses a compression algorithm without losses which allows for almost twice data compression to extend playback time. (If you remember, there is a similar data format for PC for compression of wav files without losses - Monkey's Audio, which compresses a bit better than the correctly adjusted WinRAR3, but with a plug-in for Winamp).

Thanks to compatibility of the PCM in DVD-Audio and DVD-Video, a lot of consumer receivers are DVD-Audio ready.
 

	DVD-Audio (single-layer)	DVD-Video (single-layer)	CD-DA
Size	4.7 GB	4.7 GB	0.65 GB
Channels	up to 6	up to 8	2
Bitrate (max.)	9.5 Mbit/s	6.1 Mbit/s	1.4 Mbit/s
Frequency range	96 kHz max.	48 kHz max.	20 kHz
Dynamic range	144 dB	144 dB	96 dB
Playback time (max.)	depends on the number of channels and their parameters	depends on the number of channels and their parameters	74 minutes fixed
Audio data format	PCM (optional Dolby Digital, DTS, MPEG etc.)	Dolby Digital (optional MPEG, PCM, DTS etc.)	only PCM
Sampling frequency, dual-channel audio recording	44.1 / 48 / 88.2 / 96 / 176.4 / 192 kHz	48 / 96 kHz	44.1 kHz
Sampling frequency, multichannel audio recording	44.1 / 48 / 88.2 / 96 kHz	48 kHz	-
Bit capacity	16 / 20 / 24 bits	16 / 20 / 24 bits	16 bits

A couple of words on the Sony SACD. This is a format competing against the DVD-Audio promoted by the developers of the CD-DA - SONY and Philips. Contrary to CD-DA, DVD-Video and DVD-Audio which use PCM, the SACD format is based on the PDM. Similar to the DVD-Audio, this format means twice data compression without losses, using information prediction and its further correction. Copy protection and allowed playback are encrypted and controlled by a certain pit length. First they planned on hybrid double-layer SACD/CD-DA so that they can be compatible with usual CD players, but they gave up this idea because of technical problems. Unlike the DVD-Audio, this format can't record discs or video compatible with DVD-Video but it can store text and static images.

In theory, the SACD is able to restore sound of the 100 kHz frequency range and 120 dB dynamic range. The advantages of the format are a more optimal space utilization (because of a several times lower bitrate), and better conversion provided by modern ADC/DAC's schemes of operation. Drawbacks: the format is compatible with none of the current standards and requires new equipment for audio studios and users. Besides, contrary to the PCM, the PDM format (SACD) is quite awkward in digital data processing with standard means. That is why a simple conversion of music from the current studio standard - PCM 24/96 into SACD won't give any quality improvement, apart from unnecessary changes. In case of the DSD encoding with minimal interference (for example, for pure acoustic recording), the advantages of the format can be well noticeable.

However, SACD devices are quite expensive and stuffed with a great deal of various high-quality electronic components, and it's not easy to distinguish the format from the latest achievements in the audio equipment. For instance, they often use powerful DSP which emulate analog tube sound to make a digital sound softer and to show that the SACD sounds like a good old studio analog magnetic tape. It's probable that if one invested the same money and patents into the PCM 24/96, the sound wouldn't yield to the new format.

However, the manufacturers are giving up a waiting game and splitting into alliances. The today's market offers chips of converters and players supporting both formats. One of such converters (XWM8728 from Wolfson) equips the external units of the Audigy Platinum eX we are testing today. This chip is compatible with the SACD (a special serial interface is provided) and supports the DVD-Audio stereo PCM 24bit 192kHz format.

DVD-Audio and PC

When we contacted developers of soft players the situation with DVD-Audio was a real surprise for them. InterVideo that produces WinDVD showed its interest but they have a wait-and-see attitude toward it. If DVD-Audio becomes more popular, they will add its support into their players. Cyberlink that deals with PowerDVD will add it provided that most their customers say they need it.

No hacker's tools for grabbing files from DVD-Audio are created so far.

I hope the problem of DVD-Audio playback on PC is a matter of time and inactivity of developers of soft DVD-players. Now we leave this subject until new advertisements in sound card specifications.

24/96 and PC

1. Chips supporting the 24/96 format are more expensive and, therefore, they usually have a higher-quality sound in standard 16/44 and 16/48 modes.
2. For recording and further sound processing the 24/96 format is much more preferable.

Compression of 16-bit and 24-bit dynamic range

And it's not just theory. We faced such problems when we recorded our CD "4 years of iXBT". As we took all innovations quite skeptically we made one composition in our home studio in the old 16 bit 44.1 kHz format. However, being unsatisfied with the sound quality, we used a professional card with true 24/96 support and remade everything in the new, higher-quality format.

A composition recorded and mastered in the 16bit format differed much from the one in 24bits with further 32-bit processing. The quality jump is striking with the same inexpensive recording equipment. A composition mastered in 24/96 had the same tiny details in its sound and lacked for audible distortions of compression and final maximization which are typical of anything mastered in 16/44. So, just a simple change of a format, actually without replacing the equipment, allows for such an advantage. If you have quality playback equipment you can estimate the changes having downloaded the same part from "Digital-Dream" in 16/44 (1.6 MB) and 24/96 (6 MB).

The only downside of the new format is too high requirements for computer's performance, as a data size has increased twice in bit capacity and twice in frequency. But it's not that bad. Because in case of 16/44 the sequencers do work with the higher data representation. So the load increases approximately twice. The requirements to RAM are also higher. While for 16/44 one need a PIII 1 GHz processor and 256 MB, the new format should be coupled with a 4G processor 2 GHz and 512 MB RAM.

It concerns operation with several sound tracks with simultaneous application of effects in a real-time mode. That is why if a user just wants to sample some precious records any modern entry-level system would be useful.

In closing I must say that the new generation of sound cards supporting 24/96 will improve record and playback quality now, without even DVD-Audio. And it will create some reserve for future.

Let's turn to realization of all these boons in hardware.

Terratec DMX 6fire 24/96

Terratec DMX 6fire - general view

Terratec DMX 6fire sound card - gold-plated plank and metallic stereo minijack connectors

The bracket also has a line-in; a mic-in is lacking. However, there is a mic-in with an amplification control on the commutation unit. 

Terratec DMX 6fire sound card - front view

The heart of the card is a professional PCI controller VIA/ICEnsemble ENVY24. This chip has a flexible and transparent signal routing system, high-quality mixing algorithms and doesn't let for any additional conversions in a signal. It allows for a per-bit accuracy of audio data delivery to codecs and true support of the 24/96 mode. This chip is very popular among manufacturers of audio equipment and is used, for example, in M-Audio Audiophile 2496, M-Audio Delta 410 and other cards.

Heart of the Terratec 6fire - Envy24 processor

The external unit is connected to the card with a cable looking like standard IDE. The unit houses a heap of connectors and interfaces: line-in and line-out, turntable input, mic-in with volume control and clip led, adjustable headphones-out, digital optical and coax interfaces, standard MIDI interfaces with a DIN-5 connector.

External Terratec DMX 6fire commutation unit

Software and drivers

PC test configuration:

• CPU Athlon XP 2100+; 
• 512 Mb DDR333; 
• Albatron KT333; 
• GF4 Ti4200; 
• Lynx Two; 
• Audigy Platinum eX; 
• Terratec DMX 6fire; 
• OS MS WindowsXP w/ hot-fixes; 
• MS DirectX 8.1.

• Proel 15cm microphone cable for measurements; 
• Near-field studio Event 20/20 bas monitors; 
• Behringer MX602A mixer console

(for interaction between the cards and the Event monitors); 
• Proel microphone and linear stereo cables for commutation; 
• Microlab SOLO-1 multimedia stereo speakers; 
• Sennheiser HD600 headphones.

The first tab contains elements for management of external interfaces. Signal indicators are provided and the regulators display values in dB in a 0.1 dB step. It places the card onto the professional level. Considering that the card is quite powerful and has plenty of features, its settings are not obvious. But it comes with a detailed and competent user's manual in English.