The Aragon Soundstage Preamplifier and Processor - White …
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The Aragon Soundstage Preamplifier and Processor - White Paper
by Anthony Federici
Mondial Designs Ltd
20 Livingstone Ave.
Dobbs Ferry, N.Y. 10522
Aragon Soundstage History
The understanding of the requirements for the Aragon Soundstage began in the mid 1970s. At that time I was involved in a surround sound processor/preamplifier that sold for $4000 and became the first processor accepted and implemented by the high end audio community. It was known for its utter neutrality and ability to create a natural 360 degree soundfield with the finest of recordings. Mondial Designs Ltd was established in the 1980s to create high end amplifiers and preamplifiers bearing the Aragon brand name. The goal was to create reasonably priced amplifiers with the provable credentials of the most expensive high end amplifiers. It rapidly became the amplifier of choice for speaker engineers due to its ability to drive any speaker load and remain completely stable while delivering all the power that the AC line would allow. This liberated speaker designers from the limitations of engineering to specific loads and changed the course of audio.
Soon after the release of the amplifiers, the Aragon preamplifiers also became a high end standard for containing the ultimate in engineering and parts at a reasonable price. Utilizing the Penny and Giles potentiometer for volume control, found only in preamplifiers selling for at least 4 times the cost of the Aragon, it became famous in the high end audio community for its combination of neutrality and smoothness.
We now come full circle and return to the creation of a high end surround sound processor / preamplifier, the Aragon Soundstage. First, let us examine the goals that such a project should encompass.
The Goals of High End Audio and Surround Sound are Identical
Audio was once referred to as High Fidelity and many still call it hi-fi. This refers to a high degree of fidelity to the original recording or event. In this case it usually referred to a musical event. This means that we are attempting to record and reproduce an event, such that it is indistinguishable from the original event. As time went on, mass market audio separated itself from this concept (doing things such as compressing dynamic range so it would be easier to broadcast via FM radio). The goal of pursuing fidelity to the original event, involving both the recording process and the hardware to reproduce the recording, became known as High End Audio.
It is understood that, since our sense of hearing functions at 360 degrees (you can hear sounds behind you) as opposed to your visual sense which has a far more limited field, two speakers in front cannot attempt to duplicate the original aural event. Anyone at a live concert would have heard both the direct and reflected sound coming from all sides including the rear. It is also understood, that our sense of sound provides cues of directionality which can provide warnings of impending danger approaching from the rear.
Therefore the use of recordings and hardware, which reproduces sounds that emanated from the sides and rear at the original event, brings us significantly closer to the goals of high end audio - the reproduction of a live event such that it is indistinguishable from the original.
Home Theater, the Marriage of the Aural with the Visual
Home Theater takes us to the next logical step in the attempt to recreate the live event. It brings in another sense, the sense of sight. Although video reproduction is not as advanced at deceiving the senses as audio reproduction, it requires the same dedication in the recording process and reproduction hardware for high fidelity to the original event. This means the hardware should transmit the video and the audio signal, without altering the signal, as it is transmitted from the source.. It also means that the hardware should attempt to take future recording advancements into account for both the audio and the video.
The contribution that video makes to surround sound is the facilitation of the awareness of the 360 degree aural environment. In a properly recorded movie, when the scene changes visually from a small room to a hall, the sound also changes allowing you to experience the ambient sound of a hall and thereby acoustically placing you within that space. The video also gives a rationale to the distinct sounds emanating from the rear, such as the sound of a jet departing the runway from the front, flying over your head, and gradually fading to the rear. This rationale of the visual, assisting you in understanding why there is a sound at the rear, also allows you to be comfortable with what you are hearing at the rear. If a sound emanates from the rear, without your mind understanding why it is there, it can easily make you uncomfortable. This effect is sometimes used by directors in horror movies to unsettle the viewer.
Although, at the current stage of technology, the film or video portion of the movie cannot put you into the movie, the sound can. The ultimate goal of marrying audio and video such that it completely deceives the senses into believing that what you are experiencing is real, indistinguishable from reality. The ultimate goal, of the entire process, is to involve all the senses and create an artificial "reality" completely indistinguishable from your actual reality. This all stems from the pursuits of the original scientists, engineers and enthusiasts involved in hi-fi.
Accurate Reproduction is Accurate Reproduction.
The above sentence, which appears to be a simple, mundane, and obvious truth, has apparently confused some people. There are those who believe that accurate music reproduction is different from accurate movie sound reproduction. This is utterly nonsensical. The hardware does not know if it is reproducing a singing voice or a spoken voice. The same as it doesn't know if the bell it is reproducing is being used to summon a butler or is part of a musical composition. All the hardware can be engineered to do is reproduce the signal presented to it as accurately as possible.
Home Theater Can Achieve a Higher Level of Accuracy Than a Movie Theater
A movie theater must accommodate a large number of people seated over a large area. This makes it far more difficult to engineer a system for reproducing sound accurately in a 360 degree soundfield. A home theater installation is typically in a smaller room for a far smaller number of listeners and viewers than a movie theater. Our goal in engineering the Soundstage is to provide a significantly higher level of sound reproduction than is available in a movie theater.
Implicit in the concept of attempting to recreate an experience, which is as close as possible to the reality of the live event, is that you have as few distractions as possible. Every distraction which violates this artificially created experience, pulls you out of this imaginary world. This holds true whether reading a novel, listening to a concert or watching a movie. It means that the experience should flow as naturally and unencumbered as possible. Since the controls for experiencing the artificial reality are digital, programming is involved. Making controls, as simple as possible to use, involves ergonomics. The idea of making this programming as invisible as possible to the user is Ergramming. The concept of Ergramming functions at several levels within the Aragon Soundstage.
Ergramming directly relates to the original concept of High Fidelity or High End audio. To make the transformation of the digital recording (CD, DVD etc.) to an analog reproduction, which to the listener is as close a possible to the original event, requires the use of Ergramming. This is because you must take into account how the human body and mind responds to what it is hearing, and with very low frequencies, what it is feeling. Without this you cannot attempt to create a convincing illusion.
At this point I would like to bring up an aside, having to do with movie sounds or effects. Sometimes, as may be the case with punches or gunshots, an artificial sound is used. This is done in an attempt to make you “feel” the punch or gunshot. Some people believe that this contradicts the concept of recreating the original event. However this is an erroneous belief since the director, knowing that he cannot perfectly create this artificial reality, increases the effect in an attempt to come closer to the original event. The only ability the director currently has to make you feel the punch is by using low frequencies to move the air and resonate your body, so he sacrifices aural accuracy in an attempt to stimulate another sense.
Ergramming( for Accuracy of Reproduction in Different Formats
In engineering the Soundstage we needed to take into account the potential for different requirements with different formats. For example, a listener may want more bass from the subwoofer with a movie DVD than when listening to a music CD. They may also want, for instance, a different level of center channel output for DTS than with Dolby Digital. The DVD player is capable of sending the signal for all the above formats. Ergonomics would dictate that the controls to alter a given speakers output would be easily accessible and easy to control, which they are with the Soundstage. The speaker level controls are uniquely located in the Speaker Control Quadrant at the remotes center. The button for each speaker is placed in the same location as the speaker would be in an overhead view of a room. To change output level, simply press the chosen speaker’s representative button and press either the up or down level buttons located within the quadrant.
Ergramming dictates that these changes occur automatically based on the users preferences, which they do with the Soundstage. The Soundstage owner need only use the ergonomic controls once to set their preferences for each formats speaker output levels. From then on when, for instance, a stereo music CD is played from any source the subwoofer bass output is automatically lowered.
This means that the Soundstage, a highly advanced and complex component which handles several different formats, operates as simply as a stereo component. In other words, you put a disc on and sit down, the Soundstage does the rest. This also means that Ergramming assists in the in recreating the original event since the automatic alteration of channel balance levels is for creating a more realistic soundfield while also presenting fewer distractions to the experience.
The Automatic Setup Director
The Aragon Soundstage can be easily setup, in just a few minutes, without reading the owners manual. On initial startup, the Soundstage directs you through setup via a series of questions displayed on the front panel. You are even coached as to which button you press to respond to the question. Once you have responded, and confirm your response, it automatically goes to the next question until setup is complete.
Ultra High Quality Direct Video Bypass
The Soundstage features 8 inputs of Ultra High Quality Direct Video Bypass. There are 8
S-video inputs and 8 Composite video inputs. In addition, because of our ability to create Direct Video Bypass switching, it has 3 inputs allowing for HDTV, Component or RGB (computer) video switching via our video input and output expansion port.
The S-video output was developed by the industry to yield superior color fidelity and is accepted as superior to composite under proper conditions. Unfortunately, with the majority of processors, the signal is not allowed to travel from input to output unencumbered. Various quality robbing components, such as character generators and faders, are in the signal path causing visible degradations of the original video signal. Therefore, under these circumstances, a Composite signal, going directly from the source to the video monitor or projector, can be superior to an S-video signal from the same source which travels through the processor and then to the video monitor or projector.
With the Aragon, both the S and Composite video signal paths are direct from input to output as are the HDTV, Component and RGB signal paths. The switching and bypass circuit are of such high quality, that there is no visible degradation, when the Soundstage is introduced, between the source and the video monitor or projector.
Separate Direct Analog Bypass Inputs for Both 2 Channel and 6 Channel
The Soundstage allows for passing the analog signal without conversion from analog to digital and back to analog again. It has a 2 channel bypass and a 6 channels bypass which are independent of each other. The 2 channel bypass allows for output to the subwoofer also.
Total Upgradeability via Software and Hardware for Audio and Video
“Upgradeable” is an overused word fraught with marketing hyperbole. If a single aspect of a processor is upgradeable, the word is commonly used as an overall description. “Future Proof” is another description often used with abandon, although Future Encompassing is probably a more apt title. However, neither of these terms properly defines what is upgradeable. In engineering the Soundstage we have attempted to cover every aspect of the foreseeable future.
A truly upgradeable processor must be upgradeable via both software and hardware. Software alone is not sufficient since things such as digital input receivers and D/A converters are hardware, or specifically, integrated circuits. Therefore, for us to accurately state that the Soundstage is upgradeable, we needed modular construction to allow for upgrading the circuitry itself as well as the software. In addition to every circuit board being plug in, to allow for upgrading in the field, there are expansion slots on the back panel.
One expansion slot is for a new format of digital audio input. This allows for a future DVD or CD player’s digital outputs to be connected to and processed by the Soundstage.
For the relatively near future SACD or 24/192 DVD Audio can be accommodated via upgrade. If the initial players only allow for analog output, and early adapters decide they must have them rather than wait for players with digital output, the Aragon has a 6 channel analog bypass. However, both the 6 channel analog bypass and the Digital Input Expansion Port can be used for future players beyond DVD Audio and SACD.
Another slot is for the Video Input and Output Expansion Port. This allows for future developments in video, beyond current HDTV, to be switched via the Soundstage. If both the video and audio slots are not enough, the entire rear panel is removable to allow the circuit boards to be reconfigured. Sufficient internal space is available for at least 8 channels of output allowing upgrading to 7.1 discrete channels. The Soundstage even contains an additional regulated power supply for future expansion.
The rear panel also contains an RS-232 input/output with full 2 way communication available for custom installation. It allows for full two way communication and control of the Soundstage via computer or handheld devices with output and input ports. In other words, the Soundstage is ready for the smart home of the future. This also allows for controlling any additional external circuits that may be needed in the distant future and are not accounted for internally.
8 Digital and Analog Inputs with 6 Class A Balanced and Single Ended Outputs
The Soundstage allows you to connect any 8 source devices and easily switch them in and out at the touch of a button. By allowing for separate switching between the analog and digital inputs, the Aragon actually allows you to connect 8 digital and 8 analog sources, if you so choose, for a total of 16 sources. The outputs for all the sources are Class A, either balanced or single ended. We believe balanced analog outputs are become important for home theater systems. Unlike the past, where balanced outputs were appropriate for eliminating noise picked up by long runs of interconnect between the preamplifier and power amplifier, today even short runs are susceptible to noise. This is due to the fact that digital and video source output cables are situated very close to the preamplifiers analog output cables. Since the digital and video interconnects are known radio frequency generators, they can easily introduce noise into the analog output interconnects. By having balanced outputs on the Aragon preamplifier and balanced inputs on the Aragon amplifier this noise is eliminated. The Soundstage even allows for connection to a subwoofer with balanced inputs. Since all the balanced and single ended outputs are active, any combination of balanced and single ended channels can be connected to the amplifiers with the various appropriate inputs.
Variable High and Low Pass Crossover Points
In many cases, full range speakers cannot be properly placed in a home theater system since additional factors such as televisions or screens are involved, which complicate proper setup. It is also the case that, in many instances, watching a movie is a group experience which requires speakers to be set up for a larger listening area than was typical of a high end stereo system. Since low frequencies are apt to be more susceptible to room nodes, the deeper the frequencies a speaker is capable of reproducing, the more difficult proper placement becomes. However, to maintain the cohesiveness of sound and the location of sounds, the lower one can allow a speaker to extend, without encountering room problems, the better. To achieve the best possible speaker setup, the Soundstage has 9 variable crossover points - 30, 35, 40, 45, 50, 60, 65, 70 and 80 Hertz.
Both Fixed and Variable Equalization
As stated earlier, the Soundstage is engineered to recreate the recorded soundfield as accurately as the source signal and technology allow. You will find that movies, which may appear unnaturally harsh with other processor/amplifier combinations, will be smooth and accurate with the Aragon system. There may be occasions where, due to such things as a poorly recorded source or compromises in choice of loudspeakers, the use of equalization may seem appropriate. The Soundstage provides two types of equalization.
There is a fixed equalization, which is designed to immediately subdue upper frequency harshness at the push of a button. There is also a variable equalization to make fine adjustments at both the upper and lower frequencies. When these are combined with the 9 variable crossover points and a variable subwoofer output, whose level setting is memorized and stored by format for automatic retrieval by the Soundstage, the Aragon processor has the flexibility required to achieve the highest level of sound reproduction.
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