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Bluegears b-Enspirer Review

Audiophile on a Budget!

By Josh Walrath

The CMI-8788

            C-Media announced the advanced CMI-8788 chip well over a year ago, but due to issues that are not readily apparent, it was not until late this summer that products supporting this chip were available to consumers.  It seems well worth the wait though.

            The CMI-8788 looks like a very aggressive and technologically advanced chip.  It features full 24 bit/192 KHz digital playback, 32 bit/192 KHz analog playback, and has the most DSP power to date for a C-Media product.  This DSP power is not fully disclosed, but we can assume it is far less than Creative’s X-Fi processor.  What it is able to do is enable a whole host of Dolby Digital and DTS technologies to be applied to its sound output.

The bundle is very minimal, but this not a surprise considering the price.  Bluegears does provide everything a user needs to get their card working in their computer and connected to an external receiver/decoder.

            On the Dolby Digital side it can encode a DD 5.1 stream (Dolby Digital Live at a maximum of 448 Kbps bitrate), apply 5.1 channel effects to 2 channel source material (Dolby Pro Logic IIx), Dolby Virtual Speaker, and Dolby Headphones.  For users that do utilize headphones, that last feature could be very interesting.

            On the DTS side we have DTS Connect (which is the “coverall” term for the technologies surrounding DTS Interactive and DTS Neo:PC), DTS Interactive encodes the audio stream up to 1.5 Mbps bitrate, and DTS Neo:PC upconverts 2 channel audio to 5.1/6.1/7.1.  While DD 5.1 and DTS can have wildly different bitrates, it is not exactly fair to directly compare the two.  Each uses its own form of compression, and as such there are going to be differences even if the bitrates are equal (DTS also supports lower bitrates).  Still, DTS does provide a lot more data in their stream, and as such it is often considered superior in sound to Dolby Digital 5.1.

            The 8788 also supports EAX 1 and 2, A3D 1.0, and DirectSound 3D.  While the chip may use some of its DSP capabilities towards these features, it is mostly host based.  C-Media also includes some proprietary features such as Magic Voice (changes pitch and tone of your voice through the microphone input, as well as adding reverb effects),  FlexBass (allows LFE crossover frequencies to be adjusted),  and Xear 3D (Virtual Speaker Shifter technology).

            With this generation of sound chip from C-Media, they have finally implemented ASIO support.  ASIO basically skips any of the mixing done in Windows, and allows the playback or recording of sound in a bit-accurate method.  When using standard audio in Windows, it goes through the Windows mixer which can change the audio stream by a certain amount, thereby not making it bit-accurate for digital recordings or playback.  ASIO bypasses the mixer and any other software that could affect the audio stream, and it also cuts down on the internal latency.  ASIO is very important to both professionals and audiophiles demanding bit-accurate playback and recordings.

The red PCB certainly sticks out, and it is slightly different than the reference design which was black.  The card itself is packed with many high end components which makes for some smooth sound...

Windows Vista and OpenAL

            One of the questions that has been dogging people since Microsoft announced how they will handle audio in Windows Vista is how functional will their soundcard be after upgrading to the new OS?  In the new audio driver stack put forward in Vista, hardware accelerated audio is no longer possible under Vista’s native environment.  This means that DirectSound 3D will not use the hardware buffers on cards that support it, and by extension A3D and EAX will not work in their hardware accelerated form.  So older games which utilize these 3D sound types will no longer benefit from hardware accelerated audio.  Instead the functionality will be performed by the host processor, and in so doing there can be limits on the amount of voices per sound or a lack of support for EAX or A3D in general.

            There will be games which take advantage of this new functionality in Vista which in the end allows for a less complex sound setup routine for users and applications, as well as less development time spent programming for hardware accelerated DirectSound and EAX.  We may lose some higher quality effects in the end, as the host based processor may not be able to address the performance needs of these effects.  What it will do though is end a lot of compatibility issues that we see today.

            On the other side of the equation is Creative which is trying to put forward the OpenAL standard.  This allows programs to bypass Vista’s audio stack, and directly address the hardware of the sound card.  This will allow Creative to utilize the heavy DSP functionality of its X-Fi cards, and allow the use of EAX 3, 4, and 5.  Doom 3 Engine based products have been using OpenAL for some time, and with good success (as long as the latest Creative drivers were used).

            This means that a 7.1 soundcard will still be 7.1 with Vista, but they will lose any hardware acceleration if the card is not enabled to work with OpenAL.  If the maker of the card/chip goes with OpenAL, then any hardware functionality will be supported in applications which use OpenAL.  Currently only Creative cards have OpenAL functionality with the nForce 2 apparently also supporting it.

            In speaking with developers, it seems that many are stepping away from OpenAL and other hardware implementations for their titles.  The latest generation of X-Box and PlayStation consoles feature no hardware accelerated audio, instead relying on the multi-CPU/SPE architectures to handle the sound related functions.  Developers currently have very little interest in utilizing OpenAL for consoles (though X-Box 360 does support it through Creative), as well as creating separate audio programming and content in their games to support EAX and OpenAL on the PC side.  Instead it looks more like most upcoming titles being developed for consoles and PC’s will shun any hardware accelerated audio, and will stick with software that will instead utilize the CPU(s) to perform audio tasks.  EA for instance is creating their own software audio “renderer” that will span consoles and PC games, and is bypassing OpenAL and all hardware accelerated audio.

Next:  The b-Enspirer

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