The Hercules Digifire 7.1 is designed to allow 7.1 channels of audio. but before I go into loads of the details of that I will give you a bit of background into the workings of 5.1, 6.1 and 7.1 channel sound.

5.1 Channels

5.1 channel sound is 5 channels of audio stream and 1 for the LFE (Low Frequency Effects). The setup would be 3 front speakers 1 right one centre and one left. There would then be 2 surround speakers. one left and 1 right. The .1 represents the subwoofer which is best placed out of the way under the desk etc to produce the best effects. The good thing about LFE and and the subwoofer is that it creates a feeling that the sound is everywhere despite where you put the actually speaker.

6.1 Channels

With the 5.1 sound system there was 5 channels and a LFE channel. With 6.1 however there isn't a 6th audio stream., The 6th satellite speaker is utilised  by combining the effects from the left and right channel and mixing them to produce a rear speaker. The 6.1 system is the first system to introduce a rear speaker. You will still have the 2 surround speakers on either side of your seated position but now you can be immersed in the sound, even if there are no more original sounds to be heard.

To make use of this Dolby created a new sound system called Dolby Digital Surround -EX. This system first used in cinema's and now on DVD's allows users with this special speaker setup to utilize the rear speaker by using a matrix system to mix the the left and right surround channels. This means that Dolby Digital-EX is still considered to be a 5.1 channel system because it is not "true 6.1 audio" however it does feel like it, that's good enough for most people.

7.1 Channels

The capability of the Hercules Digifire and the Dolby Digital Surround-EX system comes into play when you have the 7.1 setup. This yet again adds another surround speaker to your system. This time you have your basic 3 front speakers (left, right and centre) but this time you have left surround, right surround, left rear surround and right rear surround. This means that because you don't have a central rear speaker the Dolby track and your sound hardware will have to decide how to position this sound. The matrix system again comes into play to position your rear sounds where they need to be played. This is done again by mixing the original 2 surround channels so its still a 5.1 system but its enhanced and again it feels much better.

So the Digifire 7.1, looking at the diagram above just shows you how you can be truly immersed in sound and have a cinematic experience.

Technical Specs

• AC `97 2.1 Link CODEC, PC `99 and PCI 2.1 interface

• DSP 255 MIPS SLIMD architecture

• Supports DirectSound 3D, EAX, A3D 1.x and echo cancellation

• Wavetable synthesis with unlimited number of channels, DLS and 10-band graphic equalizer

• Supports 4 output channels

• SRC hardware and SNR 90 dB

• 96 hardware-managed 3D sound channels

• Secondary AC `97 1.0/2.1 Link CODEC for multi-channel sound and digital connection

• Asynchronous digital serial interface

• Optical S/PDIF input/output interface (PCM, AC3 5.1)

• MPU-401 MIDI Interface

• 3.3V power supply

• PCI 2.1 interface

• Cirrus Logic CS4624 chipset

• 16-bit 44.1 kHz sound quality

• 4.1, 5.1, 6.1 and 7.1 sound for games and DVD

• 96 hardware-managed DirectSound channels

• CD in and Aux in internal inputs

• Mike, Stereo Line in external inputs and MIDI/Game port on internal bracket

• 4 stereo analogue outputs for 7.1 sound

• Optical S/PDIF output

• Sensaura 3D sound engine

• Supports DS3D, EAX 1.0, 2.0, A3D 1.x, Sensaura Virtual Ear/Macro FX/Multidrive

• 52 hardware-managed DS3D channels

• General Midi and Yamaha XG compatibility

• 8 MB Wavetable software

• 64 hardware-managed polyphony channels

• Dolby Digital and DTS pass-through compatibility

• DLS and DOS real-mode compatibility

Another great feature of this card is that like the SB Audigy series it comes with a IEEE1394 ports for connecting digital video camera's or external hard drives or CD burners. You can also link to PC's with this card together to create a fast gaming network. Hercules includes Power Director Pro 2.5 for creating your home movies with you camera and add your own sounds.