[LAU] Sampling rates [WAS]: Re: jack/oversampling

[Lorenzo Sutton]

On 16/03/14 22:34, Jörn Nettingsmeier wrote:
> On 03/16/2014 09:50 PM, Lorenzo Sutton wrote:
>> On 16/03/14 19:39, Gene Heskett wrote:
>>> On Sunday 16 March 2014 14:25:14 Ralf Mardorf did opine:
>>>
>>>> On Sun, 2014-03-16 at 08:58 -0700, Len Ovens wrote:
>>>>> I would mix the project  at 48k or 96k
>>>>
>>>> Why 96 KHz? 48 KHz doesn't cause any issues, but already provides best
>>>> sound quality.
>>>>
>>> That I think is a personal call Ralf, primarily because at 48 Khz, your
>>> anti-aliasing filters had better be very very good brick walls by the
>>> time
>>> you get above 24Khz in input content
>>
>> Can anyone point out a commercially available microphone used in the
>> audio recording domain which will actually pic frequencies above 20 kHz?
>
> i once talked to a bat researcher (no joke) who had a simple mod to a
> røde nt5 that would allow it to work reasonably well up to 30k.
>
> earthworks make special versions of their excellent microphones which
> are linear up to 50khz, for those who need it (or think they need it).

ok ok... :-) I was obviously being a bit sarcastic in my statements..

[...]

>> If the audio produced is made for fruition of humans it makes absolutely
>> no sense to try and capture or reproduce anything above 20kHz, and for
>> average individuals 15kHz would probably more than enough.
>
> i'd tend to agree with that statement, but there are very valid reasons
> to do it:
> * not all recordings are meant for humans to hear - if you are measuring
> something, you might appreciate results outside of human sensation.
> * not all recordings are meant to be heard in its original frequency
> range - talk to any bat enthusiast. seriously, what those guys do makes
> you itch to try 192khz and a microphone that is open "from dc to
> daylight", as the saying goes.
> * sometimes, preservation of information is extremely important. for
> instance, there are valid reasons to digitize old analog tapes at
> ridiculous rates (say, 384 kHz): doing so lets you record traces of the
> HF bias, which might help in eliminating wow and flutter artefacts more
> precisely than tracking the 50 or 60hz power grid hum.
> or there's a colleague from italy, david monacchi, who records sound
> scapes in soon-to-be-destroyed natural habitats - why would you limit
> yourself to 10 octaves if you can get 11, before the bulldozers arrive?
> (i once heard him lecture on one of his works, and indeed he was using
> sonograms to identify certain species of animals, many of which are
> capable of uttering ultrasonics.)
>
> there is still ongoing debate about indirect audibility of high
> frequency content via transients - i'm not too convinced, but i can
> understand any colleague who would rather record too much today and then
> downsample, as opposed to finding you won't be able to fully exploit
> future distribution formats with your legacy material. if i'm not maxing
> out my equipment in terms of cpu cycles, there is no harm done in erring
> on the side of caution, if high sample rates don't incur higher costs as
> they go through the workflow.

I agree with you actually, especially with all the 'preservation' 
scenarios...
I was just being a bit provocative as to overrating gear specs..
Seriously, in all the cases you mention there is at least a thorough 
thought behind choice of specs and requirements for recording, and I 
like that.

I was also thinking of all the counter-examples, in the _music_ domain, 
recorded on technically not-so-hi-quality gear which is just great music :-)



Lorenzo.