Signal processing is carried out in the powerful and peerless Model P1 multi-channel surround sound processor. The Model P1 incorporates a true digital multi-channel signal processing path and delivers perfectly-processed audio signals to the amplifiers.
The Model P1 multi-channel processor offers these main features:
• Shaping/cleaning of the digital audio stream for an absolute minimum of jitter
• Automatic audio and video format detection
• Video ‘pass-through’, totally transparent for video processing
• All video is converted to HDMI™ out
• Handles all current audio formats, including new HD audio formats
• RoomPerfect™ room calibration on all content channels
• Automatic level and time alignment
• Pre-configured Steinway Lyngdorf speaker setups with Bass Management and crossover settings
• HDMI™ (v. 1.3 with DTS-HD Master Audio and Dolby TrueHD)
• Easy, secure software updates
• Easy, intuitive setup via web interface or on-screen display (OSD)
• Dynamic hardware platform for future upgrades
Technologies
Formats
The Model P1 accepts a PCM data stream (the format is decoded in the source player) and processes the discrete channels accordingly. However, it is recommended that the Model P1 is fed with the encoded bitstream signal, which is then recognized and properly decoded for correct processing by the Model P1. Model P1 is compatible with: Dolby Digital, Dolby Digital EX, Dolby Digital Plus, Dolby PrologicII, Dolby PrologicIIx, Dolby TrueHD, DTS, DTS-ES 6.1 Discrete, DTS-ES 6.1 Matrix, DTS 96/24, DTS-HD High Resolution Audio and DTS Master Audio, as well as stereo and mono material.
Dolby Digital, Dolby Digital EX and Dolby Digital Plus are compressed, lossy formats with up to 7.1 channels. Dolby Digital supports up to 5.1 channels. Dolby Digital EX was developed with THX Ltd. to allow more precise positioning of sounds within the sound image. This is accomplished with the addition of a rear center channel, 6.1. Dolby Digital Plus was introduced as one of the first HD audio formats and supports 7.1 channels.
The Dolby TrueHD lossless multi-channel format supports up to 8 channels. HDMI™ 1.3 is required for lossless transfer between the source player and the processing unit. Bitrates are as high as 18 Mbit/s.
DTS, DTS-ES 6.1 Discrete, DTS-ES 6.1 Matrix are comparable to the Dolby Digital formats. When implemented at twice the bitrate of DD, DTS is widely regarded as a higher-quality encoding system. DTS-ES 6.1 Matrix and DTS-ES 6.1 Discrete add a rear center channel. DTS-ES 6.1 Discrete adds a true channel, while the Matrix version encodes the signal within the two surround channels.
DTS 96/24 and DTS-HD High Resolution deliver an audio bitstream very close to the original, with up to 96kHz/24-bit resolution;, still compressed, though at a very high bitrate.
DTS Master Audio: Contains ALL the information from the original master without any compromises. Delivered bit-for-bit, it is completely lossless, like Dolby TrueHD. It supports 8 channels and operates at bitrates up to 24,5 Mbit/s.
Decoding
Employing the most advanced decoding technology available, the Model P1 can decode all current formats available in the consumer and professional markets. Lossless audio formats reproduce the original studio master recording bit for bit, as found on Blu-ray discs, in order to deliver a richly-enhanced audio experience. Any audio format received by the Model P1 can be adapted to up to 8 discrete PCM content channels.
Lip Sync
Intensive digital video processing is increasingly becoming a necessity. Consequently, some processing delay is inevitable, shifting audio and video out of sync, so that lip movements no longer match the words being heard. Obviously, this breaks the illusion and degrades the overall home theater experience. Even the slightest delay of 1 or 2 picture frames is noticeable to the human eye. The Model P1 can add a fixed delay to the audio to compensate for the delay the video processor introduces to the video. In addition, the Model P1 can help with poorly-produced material (mostly TV programs) by adding delay to the audio – even negative delay, if the video processor ‘audio offset‘ is used. The video signal itself remains untouched.
Post Processing
If the source material utilizes fewer content channels than the home theater system is capable of handling, additional content channels can be generated by post processing inside the Model P1. For example, music can be more emotionally involving in a multi-channel presentation, even when reproduced from a two-channel CD. On the other hand, there may be times when you do not want a true multi-channel experience, but prefer a more subtle two-channel version, even when watching a movie. Therefore, the Model P1 provides several post processing algorithms:
• Dolby Pro Logic II Movie, Dolby Pro Logic II Music
• Dolby Pro Logic IIx Movie, Dolby Pro Logic IIx Music, Dolby Pro Logic IIx Game
• Dolby Digital EX
• DTS Neo6 Cinema, DTS Neo6 Music
• Stereo
Adding post processing to the material can be confusing, due to the vast variation of post processing formats. In order to simplify this, the Model P1 employs ‘Audio Modes’ which relate to the desired effect, i.e. playing a stereo CD or computer game in a multi-channel format or vice versa. You can also add customized audio modes, or choose to use no post processing at all.
Sample Rate Conversion
A digital bitstream is a combination of a master clock signal and a data signal (see below). In an ideal digital world, the master clock signal would always be perfectly shaped and the digital data signal transmitted without errors and well-defined in time. In the real world, unfortunately, this is hardly ever the case, as fierce price competition encourages CD/DVD player manufacturers to use simplified design principles and inferior cable. Unfortunately, HDMI™, selected for simplicity’s sake as the standard format for transferring digital audio and video, is also a notoriously poor interface for handling that task. HDMI™ compromises the audio stream, as it is embedded in the video signal and transferred at a very high frequency.
In other words, the signal is extremely dependent on the quality of the cable or consequently, cable impedance and possible influence from external noise causes an uncertainty of the re-generated master clock, as illustrated in the drawing below (by the red vertical part of the curve). The bitstream transmission then fights a losing battle to maintain proper timing – resulting in degraded sound. Jitter is a source of disharmonic distortion to which the human ear is acutely sensitive.
In the P1, the audio signal is extracted from the active input e.g. a HDMI™ input. From the bitstream signal, the master clock rate is determined and cleaned or regenerated to minimize jitter in the re-clocking circuit before the signal is passed on in the system as secure data, relative to the clean master clock. Unique in home theater processors, this can be performed in Model P1 for an HDMI™ input, enabling high quality playback of uncompressed PCM audio over HDMI™ as well as S/PDIF and TOSLINK.
When the input signal is regenerated relative to the internal master clock, it is kept safe and clean throughout the audio chain, with no loss of dynamics all the way to the output stages of the Model A1 amplifiers.
