romanrex
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- Mar 17, 2005
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Hello, I would like to know what what is best filter (short, fast, slow) and best setting (narrow, wide, normal) to use for iem with low impedance
Features of the XDP-300R. The audio stream on the DAC always arrives at a sampling frequency of a multiple of 48 kHz. Probably, the XDP-300R was designed as a customised smartphone. It differs from smartphones on Android by a good resampling algorithm.There are no specific distortions.
This conclusion from the graphs
In Sharp modes a very strange graph of the impulse envelope
Slow mode is not better
It is well seen that the impulse envelope is not symmetrical. This asymmetry is not similar to the typical variants with the names "Minimal" or "Short".
And the Short mode itself is "curve".
The aliasing charts show unnecessary distortion in the form of harmonics (16k, 17.8k, 20k Hz). They "wrapped" inside the audible range at high frequencies.
Sharp mode
Slow mode
Short mode
The aliasing and pulse graphs differ from each other in the digital filter of the DAC. (Sharp, Slow and Short). Thus, that resampling is produced at a close frequency to 44.1 kHz. This will be 48 kHz.
If we look at the graphs with 192 kHz resampling, then all the impulse characteristics hardly differ.
Upsampling Mode 192 kHz Slow
Upsampling Mode 192 kHz Sharp
Upsampling Mode 192 kHz Short
In general, we see the Linear Slow mode for SRC.
The main difference between resampling in 192 versus "supposedly without it" is the non-availability of distortions in the field of high frequencies (16k, 17.8k and 20k Hz).
In the settings there is the option Lock Range Adjust. Somewhere, it is described as a jitter setting. For jitter, this setting is not affected in fact, but affects the resemming algorithm.
In Wide modes, you can see not the best suppression of aliasing
in narrow modes it is the best.
By indirect evidence, than "narrow", the more resource-intensive and high-quality algorithm. At the maximum there are clicks.
Для оценки работы Lock Range Adjust был выбран режим Slow.
In addition, it can be seen that the spectrum "mirrors" is not a multiple of 44 kHz (the boundaries are marked with a dashed line). The mirror boundaries are multiples of 48 kHz, which indicates a different final sampling frequency.
Maybe this is a feature of a regular player? No. When using the foobar2000 player, we get a change in the impulse response when changing the filter modes. Impulse characteristics are similar to "curves".
Thus, the best option for the Pioneer XDP-300R, is a resampling of 192 kHz. In this mode, all the characteristics are quite normal.