The following audio innovations are part of the Auzentech X-Fi HomeTheater HD audio card.

1. Hardware Structure

1.1. Design advantage

The Auzen X-Fi HOMETHEATER HD design takes full advantage of the analog audio circuitry within the limited space available while enhancing the Creative X-Fi™ technology, digital circuitry, and also providing independent module circuitry for key features, all without giving away any of the audio quality that is so important to this card. We have chosen the best components within the card's range, such as Nichicon MUSE capacitor, CS4382A DAC, high precision Clock module, to add to the quality of the audio. The Auzen X-Fi HOMETHEATER HD uses Auzentech’s proprietary technology such as the Balanced Power Generation, Headphone Amplifier, Balanced Microphone, Pointing Ground Design. We have also accurately designed the DAC filter to minimize phase changes.

Auzen X-Fi HomeTheater HD technology (above). Click to Enlarge.

2. HDMI Technology

2.1. Silicon Image TX/RX

The SiI9135A and the SiI9134 are used in many high end AVR designs. The parts support HDMI 1.3 capabilities for transmission of high fidelity audio and 12bit Deep Color per video component.

Overall link speed of the SiI9134 TX and SiI9135A RX is 225MHz allows for support of 1080p 60Hz Consumer Electronics resolutions and up to 1600x1200 UXGA PC resolutions.

The HDMI SiI9135A and SiI9134 can support HDCP Repeaters which keeps the downstream and upstream links Authenticated.

Block Diagram of Silicon Image Interface Solution

2.2. Bit-by-bit Video Output Support

Resampled Pixel data cannot be restored to its original format, which means that scaled video would not have a clear image. Moreover, through the path of “playback software -> graphic card -> HDMI audio card -> AV receiver -> HD display,” video processing would degrade the original quality. The Auzen X-Fi HOMETHEATER HD’s HDMI interface perfectly matches graphic card output to the input source signal. The "bit-by-bit" HDMI technology matches the exact data from the input to the output without alteration.

2.3. Direct HBR Transfer

Direct HBR Transfer technology allows up to 8CH, 24-bit/192kHz bitstream or LPCM output of protected high definition content transfer without down-sampling in the PC environment. In order to transfer high definition audio, the Auzen X-Fi HOMETHEATER HD has an independent driver to encrypt/decrypt and secure a DMA path for max 24Mbps high capacity stream and make pass-thru possible through HDMI.

Signal pass diagram

3. Proprietary Technology

3.1. Pointing Ground Design

In Audio circuit design, ground is the reference point of the signal and, thus, is very important. Star grounding, one of the best power amplifier schemes and considered the "base" for Hi-fi amplifier design, not only applies to Power Amplifiers. We have applied a similar technology in the Auzen X-Fi HOMETHEATER HD. Called the Pointing Ground Design™, this system greatly reduces noise and distortion in the circuitry.

A sound card ground layer is separated by analog ground, but is susceptible to a variety of noise from the motherboard. Most sound cards use multi-layer PCB, and each component has a different ground. Therefore, from the point at which the sound is generated (DAC) to the final output, there will be a long path. The noise in the ground-layer is then output through this long path.

In contrast, Auzentech's proprietary Pointing Ground Design™ shares one point for the DAC, OP-AMP, Power supply and to the output jack, stopping noise from interfering with the signal, outputting a signal with much less distortion.

 

3.2. Balanced Power Generation System

Quality power is a challenge in the PCI-Express interface, especially because the analog audio circuitry needs a Dual Supply. As the PCI-Express does not supply Negative power, the card needs to generate it. General-purpose sound cards use an inverter for the negative supply. In such a scenario, the negative and positive powers are different and affect the power supply. For this and other Auzentech PCI-Express Soundcards, we developed the "Balanced Power Generation System" to provide high quality Dual Power to the Analog circuitry and Operational Amplifier (OPAMP).

The Balanced Power Generation System simultaneously generates Positive and Negative Power from two power generators. It uses a higher frequency than the audible audio zone to propagate power, and is filtered using balanced filtering, and therefore the output is not affected by switching noise. The uniqueness of this system is that that it synchronizes the +/- power. Therefore, ripple coming from the Negative supply will provide feedback to the Positive Generator. The noise or ripple generated from one side would be reflected negatively or positively to the other side, and thus would not affect OPAMP output related to power supply.

Balanced Power Generation System structure

3.3. Professional microphone pre-amplifier

Microphone signal level is very small, and thus weak in relation to external noise. Therefore, most professional microphones used a Balanced Connection system.

When in “BALANCE” mode, the Auzen X-Fi HOMETHEATER HD supports professional Balanced Microphones (configured using on-board jumper; see image). The MIC Pre-Amplifier has a very low E.I.N and over -60 dB CMRR (Common Mode Rejection Ratio).

2.3.1. Balanced / Unbalanced Microphone

As the diagram shows above, the Microphone connection needs Signal Line and Ground Line; this is called Unbalanced Transfer. When using Unbalanced Transfer, there is no way eliminate external noise from the Signal Line; HUM or RF Noise will be amplified through the amp, together with the original signal.

Balanced transfer uses Phase Reverse to eliminate noises other than the original sound expected, for professional-quality MIC input.

2.3.2. Connection to the Balanced Microphone

It is possible to connect a Balanced dynamic MIC or Powered Balanced condenser MIC. Most MIC cable will use 1/4” Phone jack, and thus will need a converter to be able to use these MICs.

2.3.3. Connection to a Multimedia Microphone

When in “STEREO” Mode, it is possible to use Mono Multimedia Condenser microphone and Multimedia Stereo microphone. The Left and Right channel sound will be mixed when input.

3.4. Headphone Amplifier

The Auzen X-Fi HOMETHEATER HD Headphone Jack uses an independent Headphone Amplifier. It is not there to simply to provide an additional output. It is there to provide a listening experience limited only by the quality of your headphones.

Common thinking has it that you can get good sound by connecting your headphone to line output. The Auzen X-Fi HOMETHEATER HD headphone amplifier is not there just to amplify the sound, but to lower the output impedance and improve Damping and drive capability. We can consider the headphone as a small speaker, and thus complicated physics and electronics factors are all adapted in the headphone. Therefore, if the amp output driver capability is weak—even if you pump up the volume—the sound will be powerless, have wide/low sound, high sounds that lack clarity, and distortion.

You can see the difference of having the Headphone output jack and Line out (FRONT) output with the Headphone.

Low Frequency

Line Output (L), Headphone Output (R)

In the Low Frequency chart, compare Line output (Left) and Headphone output (Right). With Headphone amplifier Output, the output is the original square wave. With line output, the lack of damping means that the amplifier cannot restrain Headphone unit vibration, creating resonance.

 

High Frequency

Line Output (L), Headphone Output (R)

In the High Frequency chart, compare the Line Output (Left) and Headphone Output (Right). With Line Output, notice the development of “overshoot” and severe distortion due to the lack of the wave’s “driving speed.”

You can see from this graph that when connecting the Headphone amplifier, it shows a stable output in all range of frequency, but when connecting headphone to the line output, due to the headphone impedance curve, it will affect the output.

What is the Headphone Amp in the Auzen X-Fi HOMETHEATER HD?

The Auzen X-Fi HOMETHEATER HD has a separate Headphone Output Circuitry. This is implemented for the Rear Panel and Front Panel headphone outputs of your PC.

This Headphone Amplifier does not use a normal amplifier chip (IC). Instead, it uses a proprietary Auzentech-designed dedicated Headphone Amplifier. Based on the OPAMP, it has eight (8) high-end discrete transistors (buffer Class-AB type) in the headphone driver stage. This Headphone Amplifier can support up to 100mW/channel output (power), and thus you can connect any type of headphone and hear the audio you desire (compared to the line-out configuration, which supports only up to 7mW/channel). The Headphone Amplifier provides the precision of an OPAMP with a superior audio specification, while at the same time providing powerful damping and driving capability, and more dynamic sound and stability in all frequency ranges.

3.5. Audio Parts

"Nichicon MUSE" ES Series (Bi-Polarized Aluminum Electrolytic Capacitor)

Comparable to a UV filter when using a camera, the Coupling capacitor filters DC and components for a cleaner sound. The Auzen X-Fi HOMETHEATER HD includes Nichicon’s Audio condenser MUSE ES series. This is a Bi-Polarized Aluminum Electrolytic Capacitor which gives more depth to the background and provides solid sound to the bass.

Highest quality Metalized Film Capacitor & Precision registers

Metalized Film Capacitors take full advantage of the superiority of a Film capacitor while minimizing inductance, and are used for the Front channel’s DAC filter. Moreover, the sound card uses resisters accurate to 1 percent in all the audio circuitry, and AVX’s yellow Tantalum capacitor which has excellent low ESR (Equivalent Series Resistance).

CS4382A (High performance Multi channel 24-bit/192kHz stereo DAC)

- Selectable Digital filter
- 24bit 8x Digital Filter
- THD+N : -100dB
- DR, S/N : 114dB
- Low-clock-jitter

The DAC is the final part that is used to make the analog sound, and is key in deciding the level of your soundcard. This sound card uses Cirrus Logic’s Multi bit architecture DAC 114dB CS4382A for the Multichannel output.

Coaxial Transformer

Hi-End Coaxial transformer technology has been implemented in the Auzen X-Fi HOMETHEATER HD, in particular to minimize "jitter" when using longer cable. Coaxial transformers are better and more stable for S/PDIF Coaxial output signal, but most soundcards omit them.

 

4. Audio Performance

As with other sound cards, the quality of the Line-in is lower in the Auzen X-Fi HOMETHEATER HD than the quality of line-out. Therefore, one cannot simply test Line-in to line-out using a loop back test to draw conclusions regarding sound card quality. Usually RMAA Testing is done through Loop-back test (Line in – Line out), and thus it cannot be better than the ADC spec (102dB). In our testing, if the testing is similar to the "Line input," we conclude this test was performed successfully. Below is Additional information on our testing:

Frequency response: When performing RMAA testing, it can show "Very Good" although the current result is "Excellent." The reason for this is because in 15 kHz, the level can fall a bit. This is intentional because the sound card is targeting the "Hi-Fi" market. The DAC filter, for example, is tuned for "Hi-Fi."

THD: The Front channel uses a DIP type OP-AMP and capacitor, and thus will show a higher number on the THD. Also, in the Hi-Fi market, a card with a lower THD would produce a sound that can become too "flat."

4.1. Multichannel output

Testing chain: Auzen X-Fi™ HOMETHEATER HD Outputs – Measurement system Input

Sampling mode: 24-bit, 48 kHz

Summary

Frequency response (from 40 Hz to 15 kHz), dB:	+0.02, -0.19	Excellent
Noise level, dB (A):	-113.1	Excellent
Dynamic range, dB (A):	113.1	Excellent
THD, %:	0.0005	Excellent
IMD + Noise, %:	0.0016	Excellent
Stereo crosstalk, dB:	-112.6	Excellent
IMD at 10 kHz, %:	0.0050	Excellent

General performance: Excellent

Frequency response

Frequency range	Response
From 20 Hz to 20 kHz, dB	-0.35, +0.02
From 40 Hz to 15 kHz, dB	-0.19, +0.02

Noise level

Parameter	Left	Right
RMS power, dB:	-111.6	-111.6
RMS power (A-weighted), dB:	-113.1	-113.1
Peak level, dB FS:	-76.4	-76.3
DC offset, %:	-0.00	-0.00

 

Dynamic range

Parameter	Left	Right
Dynamic range, dB:	+112.0	+112.0
Dynamic range (A-weighted), dB:	+113.1	+113.1
DC offset, %:	-0.00	0.00

 

THD + Noise (at -3 dB FS)

Parameter	Left	Right
THD, %:	0.0006	0.0005
THD + Noise, %:	0.0010	0.0010
THD + Noise (A-weighted), %:	0.0010	0.0009

 

Intermodulation distortion

Parameter	Left	Right
IMD + Noise, %:	0.0015	0.0015
IMD + Noise (A-weighted), %:	0.0013	0.0012

 

Stereo crosstalk

Parameter	L <- R	L -> R
Crosstalk at 100 Hz, dB:	-110	-119
Crosstalk at 1 kHz, dB:	-111	-112
Crosstalk at 10 kHz, dB:	-103	-102

IMD (swept tones)

Parameter	Left	Right
IMD + Noise at 5 kHz, %:	0.0031	0.0031
IMD + Noise at 10 kHz, %:	0.0050	0.0049
IMD + Noise at 15 kHz, %:	0.0069	0.0069

The following audio innovations are part of the Auzentech X-Fi Forte soundcard, Auzentech´s first Low Profile native PCI Express® audio card designed especially for gamers and audiophiles.

Headphone Amplifier

The Auzen X-Fi™ Forte 7.1 Headphone Jack uses an independent Headphone Amplifier. It is not there to simply to provide an additional output. It is there to provide a listening experience limited only by the quality of your headphones.

Common thinking has it that you can get good sound by connecting your headphone to line output. The Auzen X-Fi™ Forte 7.1 headphone amplifier is not there just to amplify the sound, but to lower the output impedance and improve Damping and drive capability. We can consider the headphone as a small speaker, and thus complicated physics and electronics factors are all adapted in the headphone. Therefore, if the amp output driver capability is weak—even if you pump up the volume—the sound will be powerless, have wide/low sound, high sounds that lack clarity, and distortion.

You can see the difference of having the Headphone output jack and Line out (FRONT) output with the Headphone.

• In the Low Frequency chart, compare Line output (Left) and Headphone output (Right). With Headphone amplifier Output, the output is the original square wave. With line output, the lack of damping means that the amplifier cannot restrain Headphone unit vibration, creating resonance.
• In the High Frequency chart, compare the Line Output (Left) and Headphone Output (Right). With Line Output, notice the development of “overshoot” and severe distortion due to the lack of the wave’s “driving speed.”

You can see from this graph that when connecting the Headphone amplifier, the output is stable output in all frequency ranges. When connecting the headphone to the line output as do standard soundcards, however, the output is unstable due to the headphone impedance curve.

More about Auzen X-Fi™ Forte 7.1 Headphone Amp

The Auzen X-Fi™ Forte 7.1 has a separate Headphone Output Circuitry. This is implemented for the Rear Panel and Front Panel headphone outputs of your PC.

This Headphone Amplifier does not use a normal amplifier chip (IC). Instead, it uses a proprietary Auzentech-designed dedicated Headphone Amplifier. Based on the OPAMP, it has eight (8) high-end discrete transistors (buffer Class-AB type) in the headphone driver stage. This Headphone Amplifier can support up to 100mW/channel output (power), and thus you can connect any type of headphone and hear the audio you desire (compared to the line-out configuration, which supports only up to 7mW/channel). The Headphone Amplifier provides the precision of an OPAMP with a superior audio specification, while at the same time providing powerful damping and driving capability, and more dynamic sound and stability in all frequency ranges.

Microphone Pre-Amp

Microphone signal level is very small, and thus weak in relation to external noise. Therefore, most professional microphones used a Balanced Connection system.

When in “BALANCE” mode, the Auzen X-Fi™ Forte 7.1 supports professional Balanced Microphones (configured using on-board jumper; see image). The MIC Pre-Amplifier has a very low E.I.N and over -60 dB CMRR (Common Mode Rejection Ratio).

Connection to the Balanced Microphone

It is possible to connect a Balanced dynamic MIC or Powered Balanced condenser MIC. Most MIC cable will use 1/4” Phone jack, and thus will need a converter to be able to use these MICs.

Connection to a Multimedia Microphone

When in “STEREO” Mode, it is possible to use Mono Multimedia Condenser microphone and Multimedia Stereo microphone. The Left and Right channel sound will be mixed when input.

Balanced / Unbalanced Microphone

Unbalanced Transfer

As the diagram shows above, the Microphone connection needs Signal Line and Ground Line; this is called Unbalanced Transfer. When using Unbalanced Transfer, there is no way eliminate external noise from the Signal Line; HUM or RF Noise will be amplified through the amp, together with the original signal.

Balanced Transfer

Balanced transfer uses Phase Reverse to eliminate noises other than the original sound expected, for professional-quality MIC input.

Two Analog to Digital Converters (ADCs)

X-Fi™ Forte has two Analog to Digital Converters (ADCs), a Wolfson WM 8775SEDS and a Wolfson WM8782S, used as follows:

• WM8775SEDS: Rear Microphone, Line Input, Aux Input.
• WM8782S: Front Panel Microphone.

With two ADCs, you can use two input ports independently. For example, you can use Front Panel Microphone Input and Rear Line Input simultaneously, and perform mixing or recording.

With two ADCs, X-Fi™ Forte is designed for Microsoft® Vista. In Vista there is a separate driver for each input jack (Microphone Driver, Line-In Driver, and so on).

Pointing Ground Design™

In Audio circuit design, ground is the reference point of the signal and, thus, is very important. Star grounding, one of the best power amplifier schemes and considered the "base" for Hi-fi amplifier design, not only applies to Power Amplifiers. We have applied a similar technology in the Auzen X-Fi™ Forte 7.1. Called the Pointing Ground Design™, this system greatly reduces noise and distortion in the circuitry.

A sound card ground layer is separated by analog ground, but is susceptible to a variety of noise from the motherboard. Most sound cards use multi-layer PCB, and each component has a different ground. Therefore, from the point at which the sound is generated (DAC) to the final output, there will be a long path. The noise in the ground-layer is then output through this long path.

In contrast, Auzentech's proprietary Pointing Ground Design™ shares one point for the DAC, OP-AMP, Power supply and to the output jack, stopping noise from interfering with the signal, outputting a signal with much less distortion.

Balanced Power Generation System

Quality power is a challenge in the PCI-Express interface, especially because the analog audio circuitry needs a Dual Supply. As the PCI-Express does not supply Negative power, the card needs to generate it. General-purpose sound cards use an inverter for the negative supply. In such a scenario, the negative and positive powers are different and affect the power supply. this and other Auzentech PCI-Express Soundcards, we developed the "Balanced Power Generation System" to provide high quality Dual Power to the Analog circuitry and Operational Amplifier (OPAMP).

The Balanced Power Generation System simultaneously generates Positive and Negative Power from two power generators. It uses a higher frequency than the audible audio zone to propagate power, and is filtered using balanced filtering, and therefore the output is not affected by switching noise. The uniqueness of this system is that that it synchronizes the +/- power. Therefore, ripple coming from the Negative supply will provide feedback to the Positive Generator. The noise or ripple generated from one side would be reflected negatively or positively to the other side, and thus would not affect OPAMP output related to power supply.

Balanced Power Generation System´ structure

Audio Performance

As with other sound cards, the quality of the Line-in is lower in the Auzen X-Fi™ Forte 7.1 than the quality of line-out. Therefore, one cannot simply test Line-in to line-out using a loop back test to draw conclusions regarding sound card quality. Usually RMAA Testing is done through Loop-back test (Line in – Line out), and thus it cannot be better than the ADC spec (102dB). In our testing, if the testing is similar to the "Line input," we conclude this test was performed successfully. Below is Additional information on our testing:

Frequency response: When performing RMAA testing, it can show "Very Good" although the current result is "Excellent." The reason for this is because in 15 kHz, the level can fall a bit. This is intentional because the sound card is targeting the "Hi-Fi" market. The DAC filter, for example, is tuned for "Hi-Fi."

THD, %: When looking at the result, the Front channel´s Dynamic range is 116.0 dB, but the THD,% is 0.0012. On the contrary, Multi-channel output´s Dynamic range is 112.8 dB, but the THD,% is 0.0006 which is better than the Front. However, the chip spec is 0.001% and thus not causing issues. The Front channel uses a DIP type OP-AMP and capacitor, and thus will show a higher number on the THD. Also, in the Hi-Fi market, a card with a lower THD would produce a sound that can become too "flat."

Front Channel Output

Testing chain: Auzen X-Fi™ Forte 7.1 Front Output – Measurement system Input
Sampling mode: 24-bit, 48 kHz

Summary

General performance: Excellent

Frequency response

Noise level

Dynamic range

THD + Noise (at -3 dB FS)

Intermodulation distortion

Stereo crosstalk

 

 

IMD (swept tones)

 

Multichannel Output

Testing chain: Auzen X-Fi™ Forte 7.1 FrontOutput – Measurement system Input.
Sampling mode: 24-bit, 48 kHz

Summary

General performance: Excellent

Frequency response

Noise level

 

Dynamic range

 

THD + Noise (at -3 dB FS)

Intermodulation distortion

Stereo crosstalk

IMD (swept tones)

Auzentech's World Firsts helped to revitalize the sound card industry.

• Auzentech released the World's first Dolby® Digital Live Sound (DDL) card (X-MYSTIQUE 7.1 Gold)
• Auzentech released the World's first DTS™ Connect Sound Card ( X-PLOSIONâ„¢ 7.1 DTS™ Connect).
• Auzentech is first third-party company to release a Creative X-Fi™ sound cards with DDL & DTS Connect features (X-Fi™ Prelude, X-Fiâ„¢ Forte)
• Auzentech is the first company to demonstrate a fully compliant HDMI™ 1.3 soundcard (X-Fiâ„¢ HomeTheater HD).