Originally Posted by batpig
Out of curiosity, where did you get that info about "AL24 Plus" versus "Advanced AL24"? It's very hard to dig up good info on Denon's proprietary stuff.
My sources are image linked pop up windows on the Denon web site:
ALPHA processing is the world's first technical formula for reproducing an analog waveform from the reproduction of 16-bit data in 20-bit quality. The ALPHA processor interpolates the digital data recorded on a CD and reproduces it in a waveform that is very close to the way these musical signals would look in a natural analog waveform.
AL24 Processing is a newly developed technology that reduces quantization distortion and represents the ultimate analog waveform reproduction that is designed to support the higher numbers of bits and higher sampling rate of next-generation media. It senses the nature of the digital data being input and interpolates the data so that it faithfully replicates the original analog waveform.
Denon has further developed its proprietary AL24 Processing, an analog waveform reproduction technology, to support the 192-kHz sampling frequency of DVD-Audio. This new technology thoroughly suppresses quantization noise with D/A conversion of LPCM signals to reproduce the low-level signals with optimum clarity that brings out all the delicate nuances of the music. For additional information, visit the Denon Tech Showcase.
The acclaimed Advanced AL24 DSP processing improves the fidelity of high resolution stereo PCM sources such as CD and DVD (up to 192kHz sampling frequencies). Through sophisticated DSP processing algorithms, it improves low level detail and enhances fidelity by up-sampling and adaptive filtering techniques. Advanced AL24 also provides increased dynamic range and spatial information, bringing out all the nuances with optimum clarity and natural fidelity. For additional information, visit the Denon Tech Showcase.
In addition to the existing AL24 Processing Plus bit expansion technology, DENON has also developed Advanced AL24 Processing that dramatically improves information volume in the time axis region using high-speed signal detection and processing technology. In addition to expanding original 16-bit digital data to 24 bits, Advanced AL24 Processing uses data interpolation along the time axis or up-converted sampling to achieve natural interpolation without losing the original data. Advanced AL24 Processing Multi Channel is conducted for all channels and modes other than DSD DIRECT.
From that info, I have inferred the following:
ALPHA Processing -> AL24 Processing -> AL24 Processing Plus -> Advanced AL24 Processing
ALPHA Processing is a bit depth expansion process: 16 bit input, 20 bit output.
AL24 Processing is a bit depth expansion process: 16 bit or 20 bit input, 24 bit output.
AL24 Processing Plus is a bit depth expansion process: 16 bit or 20 bit input, 24 bit output. AL24 Processing Plus supports input signals w/ a greater range of sample rates, up to 192 kHz.
Advanced AL24 Processing is a bit depth expansion process: 16 bit or 20 bit input, 24 bit output. Advanced AL24 Processing is also an upsampling process: 32 kHz, 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz, or 176.4 kHz input, 192 kHz output.