Converting to Higher Bitrates??....we goofed.

[Bobbsy]

Well, the usual argument in favour of high bit rates (and I stress it's an argument that I don't personally subscribe to) is not the ability to record higher frequencies. Rather, it's claimed that the higher resolution translates to a more accurate representation of the original waveform.

However, as I said before, I firmly believe Mr. Nyquist was right.

 

[ecc83]

Well, the usual argument in favour of high bit rates (and I stress it's an argument that I don't personally subscribe to) is not the ability to record higher frequencies. Rather, it's claimed that the higher resolution translates to a more accurate representation of the original waveform.

However, as I said before, I firmly believe Mr. Nyquist was right.

Agreed good Sir but there are quite a few who argue that a wide bandwidth, way past human limits, is better, be it mic pres, power amps or converters!

The implication to the uninitiated is in any case "double the sampling rate, double the bandwidth" and many purveyors of interfaces do nothing to dispell this idea.

Dave.

 

[Farview]

Hi Jay,
Can I also add that if you delve into the specc's of many AIs they do NOT double the bandwidth for a 96kHz rate instead the claimed upper frequency response is something like 25kHz!
Then, there are very few mics that even GET to 20kHz leave alone surpass it.

Dave.

There are also very few playback systems that can reproduce it. There also isn't that much info up there. Most people over 30 can't hear much over 15k. Etc, etc....

 

[Farview]

Well, the usual argument in favour of high bit rates

Do you mean sample rates, or bit depth?

 

[Bobbsy]

I meant sample rates of course but I was referring to the title of this topic...obviously in too obscure a manner!

In terms of bit depth, I'm a big fan of MIXING in 32 bit floating point but that's a different thread methinks.

 

[philbo]

If you just plan using them for scratch tracks, loop the output of the audio interface back to the input and just re-record in one app while playing it back in another. The loss of fidelity won't matter if you don't plan to use them in the final mix anyway.

But, I agree with everybody else on this: doubled sample rate doesn't really buy you much. Maybe a 1% improvement in fidelity, if you have great monitors and a room with proper acoustic treatment. Otherwise, nobody will hear any difference.

However, I always record with 24 bit word width. Notwithstanding my great respect for Ethan Winer, I find 24 bits give me a better result than 16. Better sounding (especially at low levels), more articulation, and easier to set levels.

 

[Farview]

In terms of bit depth, I'm a big fan of MIXING in 32 bit floating point but that's a different thread methinks.

I never understood the point of that. There are no 32 bit fp converters, so all you are doing is recording at 24 bit and adding 8 zeros to it. The DAW already works at 32f, so I don't see what difference it makes. Of course, I do a very minimum of processing the actual audio files. I do all the processing in the mix, so that might be why I don't see the advantage.

 

[Ethan Winer]

it's claimed that the higher resolution translates to a more accurate representation of the original waveform. However, as I said before, I firmly believe Mr. Nyquist was right.

Yes, of course Nyquist was right. Further, it's trivial to prove that 44/16 is perfectly capable of capturing audio at a resolution that far exceeds what the ear can hear. For the amusement of all in attendance I repeat this link:

Converter Loop-Back Tests

--Ethan

 

[dgatwood]

Yes, of course Nyquist was right. Further, it's trivial to prove that 44/16 is perfectly capable of capturing audio at a resolution that far exceeds what the ear can hear.

Not for those of us who can actually hear above 20 kHz.... I'm not saying there's much useful up there, but last I checked my hearing, at sufficient volume, I could hear up to 24 kHz, at which point, I couldn't crank my speakers any higher....

 

[Bobbsy]

Well, that makes you a very rare critter, dgatwood. I was very proud when at age 50 I could still hear frequencies up to just over 15kHz (nearing 60 now that's rolled off dramatically). The worrying thing was that at the same time I tested my then-19 year old son and some of his friends (all from the loud clubbing and iPod/earbuds generation) and some of them rolled off earlier than I did.

However, I'd be curious about your methodology for the test because the "at sufficient volume" part might be a clue. Are you sure you weren't hearing low level harmonics rather than the fundamental? "At sufficient volume" I can also hear something at 20kHz--but it's a harmonic at around 10k rather than actually hearing 20kHz.

 

[Farview]

Exactly. If you have to turn it up really, really loud, that doesn't count. It would be the same as saying your 4 inched driver can go all the way down to 40 Hz...if you turn it up loud enough.

 

[ecc83]

Exactly. If you have to turn it up really, really loud, that doesn't count. It would be the same as saying your 4 inched driver can go all the way down to 40 Hz...if you turn it up loud enough.

Of course! You test ears the same way you would test any wideband audio "device" for frequency response. You keep the input signal level VERY constant whilst measuring the output. Hey! Hands up: How many people reading this have ever done a response check on an amplifier with an oscillator, scope and audio millivoltmeter (usually scaled in dB ref 1V, cos at least in MY game, 600Ohms is looong dead!)?

You can see specifications for speakers "Response up to 40kHz". What response? Smoke?

And in general people DO NOT do sine wave tests on "consumer" kit unless you really know what you are at. 10kHz might not SOUND loud but you would be suprised how quickly it can kill amps and tweeters.

Dave.

 

[dgatwood]

However, I'd be curious about your methodology for the test because the "at sufficient volume" part might be a clue. Are you sure you weren't hearing low level harmonics rather than the fundamental? "At sufficient volume" I can also hear something at 20kHz--but it's a harmonic at around 10k rather than actually hearing 20kHz.

I'm pretty sure. My perception was that the pitch continued to get higher, anyway. The 16 kHz flyback frequency on TVs always drove me nuts until everything went LCD.

Of course! You test ears the same way you would test any wideband audio "device" for frequency response. You keep the input signal level VERY constant whilst measuring the output.

To be fair, my speakers only claim response up to 20 kHz, so keeping the input to my ears constant almost certainly requires not keeping the speakers' volume constant....