trew wrote:What is this "Sergey Petrov experimental SRC" thing I keep seeing?
I'm sensing placebo effect, not sure...
Yes, if all the true knowledge is already in The Holy Book, an alternative Holy Book may only produce a "placebo effect".
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trew wrote:What is this "Sergey Petrov experimental SRC" thing I keep seeing?
I'm sensing placebo effect, not sure...
hiro wrote:Do you want to give us more and more truisms, or will you share your actual experiences?
trew wrote:I couldn't agree more with hiro ...
Disregard all that, I found FreeBSD 8+ resampler better suite for me and my project. It is at least twice, triple or quad better than the current "Production quality" of what OSSv4 can offer, both in term of speed and quality.
http://people.freebsd.org/~ariff/z/src/
hiro wrote:trew wrote:http://people.freebsd.org/~ariff/z/src/
Isn't that the same? grc3 is fromm OSS...
igorzwx wrote:Many thanks for very interesting information!
Is it available as a standalone converter?
igorzwx wrote:Would you be so kind as to provide some recommendations for testing scenarios, or a kind of "howto"?
hiro wrote:trew wrote:http://people.freebsd.org/~ariff/z/src/
Isn't that the same? grc3 is from OSS...
hiro wrote:@trew How did you "measure" quality? Have you by any chance also compared to libsamplerate?
hiro wrote:According to this site oss production quality creates distortions at about -110db.
hiro wrote:Yeah, it says grc3 is fixed point.
According to this site oss production quality creates distortions at about -110db. If you have a good system and ear you should hear it. But only if you listen to very quiet 24bit files!
Try out this nice internet radio station: http://radio.cesnet.cz:8000/cro-d-dur.flac
libsamplerate has a very linear phase and distortions under 150db, which is not even inside the dynamic range of 24bit.
I'll consider using Z on my ARM, which is very slow with floating points. Thanks for bringing this up again.
in practice, a signal can never be perfectly bandlimited, since ideal "brick-wall" filters cannot be realized. All practical filters can only attenuate frequencies outside a certain range, not remove them entirely. In addition to this, a "time-limited" signal can never be bandlimited. This means that even if an ideal reconstruction could be made, the reconstructed signal would not be exactly the original signal. The error that corresponds to the failure of bandlimitation is referred to as aliasing. http://en.wikipedia.org/wiki/Nyquist%E2 ... iderations
It can be argued that analog formats retain some inherent advantages over digital formats. The advantages of analog systems are summarised below:
Absence of aliasing distortion
Absence of quantization noise
Behaviour in overload conditions
Aliasing
Unlike digital audio systems, analog systems do not require filters for bandlimiting. These filters act to prevent aliasing distortions in digital equipment. Early digital systems may have suffered from a number of signal degradations related to the use of analog anti-aliasing filters, e.g., time dispersion, nonlinear distortion, temperature dependence of filters etc. (Hawksford 1991:8). http://en.wikipedia.org/wiki/Analog_rec ... advantages
Each numerical value measured at a single instant in time for a single signal is called a sample; samples are measured at a regular periodic rate to record a signal. The accuracy of the conversion process depends on the sampling rate (how often the sound is sampled and a related numerical value is recorded) and the sampling depth, also called the quantization depth (how much information each sample contains, which can also be described as the maximum numerical size of each sampled value). http://en.wikipedia.org/wiki/Analog_rec ... _recording
The [Nyquist] theorem also leads to a formula for reconstruction of the original signal. The constructive proof of the theorem leads to an understanding of the aliasing that can occur when a sampling system does not satisfy the conditions of the [Nyquist] theorem. http://en.wikipedia.org/wiki/Nyquist%E2 ... ng_theorem
Now we get into the real voodoo. Audiophiles have claimed since the beginning of digital audio that vinyl records on an analog system sound better than digital audio. Indeed, you can find evidence that analog recording and playback equipment can be measured up to 50khz, over twice our threshold of hearing. Here's the great mystery. The theory is that audio energy, even though we don't hear it, exists as has an effect on the lower frequencies we do hear. Back to the Nyquist theory, a 96khz sample rate will translate into potential audio output at 48khz, not too far from the finest analog sound reproduction. This leads one to surmise that the same principle is at work. The audio is improved in a threshold we cannot perceive and it makes what we can hear "better". Like I said, it's voodoo. http://www.tweakheadz.com/16_vs_24_bit_audio.htm
delude yourself if you must believe that digital contains more information than analog... If you listen to crap played through crap, how can you possibly ascertain quality reproduction? http://www.audioasylum.com/cgi/t.mpl?f=vinyl&m=5232
The current crop of AD [analog-to-digital] converters utilized in music can sample at rates up to 192 kilohertz. High bandwidth headroom allows the use of cheaper or faster anti-aliasing filters of less severe filtering slopes. The proponents of oversampling assert that such shallower anti-aliasing filters produce less deleterious effects on sound quality, exactly because of their gentler slopes. Others prefer entirely filterless AD conversion, arguing that aliasing is less detrimental to sound perception than pre-conversion brickwall filtering.
http://en.wikipedia.org/wiki/Analog-to- ... _recording
hiro wrote:I took the grc3 results for granted. It doesn't seem trivial to test, so I probably won't.
I already told you the reason I haven't tried that resampler: I don't have the source (I don't run random stuff not even knowing where it's coming from).
Also, why should I test something nobody would ever use or know. What's the use of it? We all know it can't be "perfect" and we all still have converters which are good enough.
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