What do you mean? The level axis is more than 24dB, what more do you want?
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Can we hear the bottom bits of 24?
- Thread starter earlevel
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- Thread Starter
- #82
I can tell you right now that I hear the 16-bit file, playing it directly from dropbox without downloading, as expected for 16-bit. Sure, I can open it in something else (why not RX 8? an excellent and accurate analysis tool).Here are the download link of the files that I have downloaded using the links on your post. I only linked the two files that are empty. The 5-bit file is not empty.
Dropbox - File Deleted - Simplify your life
www.dropbox.com
Dropbox - File Deleted - Simplify your life
Please open them in an audio editor, not an audio cleaning software like iZotope RX 8, and post what you see.
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- Thread Starter
- #83
Maybe this is the problem as to why you didn't like the idea of my tones—maybe you misunderstand what they are?
The peak amplitude is -90 dB for the 16-bit file. It's -138 dB for the 24-bit file. You aren't going to see anything on something with the lowest tick at -24 dB.
Just turn up your sound system, you'll hear the "16-bit" tone.
I guess I learned that what I thought was obvious may not be so obvious. But I did link to the article, which explains the waveforms in detail.
So you recorded silence!
I am sorry but that is the oddest thing I have encountered on the entire 50 years of my professional life.
So what is the audible spec? Is there one?
Bit 16/24/32
Frequency 44 48 96 …..
Bit 16/24/32
Frequency 44 48 96 …..
I read the article now but I still find it a very odd thing to do. (I missed the link at the end of your post, I am sorry for that.) You are trying to audition the noise floor. What is the point?
Be glad there isn't a full scale19kHz tone mixed in...
THIS! - and it's not necessarily about limiting/compression - the actual material won't require 24 bits, but you don't know the peaks/troughs until after its recorded...
Once you have it on your DAW - you can move the 16bit window to fit the actual recording, and dump the excess bits.... (mostly move it up, so the maximum peak is 1db below max....) 24 or even 32 bits is valuable margin when recording.... but I am not convinced it serves any purpose in the final mastered product.
There is clear audible difference in noise floor between 16-bit and 18-bit and on extremely good systems, 19-bit should be audible. The issue is, in DAC design the next step up from 16-bit is 24-bits. So we use a 24-bit DAC even though it can resolve at most 19-20 bits.
- Thread Starter
- #92
OK, no problem, and I didn't consider that have them all in 24-bit containers might make someone think something was amiss.
Well, I think I explained but I'll try a different way.
I feel that having references are helpful. For instance, here we talked about SPL. If I were discussing SPL with someone here in my office, and they asked about what levels people monitor at, and how loud a given level might seem, and what's the quietest a person might listen to music, I'd be able to get the point across a lot faster if I had an SPL meter handy and gave examples. "OK, this is Opeth at 90 dB SPL at your ears", "You're listening to this video dialog at 65 dB SPL".
For the 24-bit file: I can say, "you can't hear that" till I'm blue in the face. If people don't know they can't hear it, they think the reality is I can't hear it, and I'm spreading disinformation (no exaggeration, I've been told this). After all, many of top recording engineers have told them online that they can easily hear the last bit. But...if they play with the "24-bit" sweep (2-lsb peak-peak) for a while, they may come to realize...there might be a possibility it's un-hearable, at least at any realistic listening level.
And the "16-bit" gives a realistic expectation for the noise floor of CD. It's easy to hear by itself, but pretty quiet compared with full-on music. Dithered 16-bit is more subtle, I'm purposely giving an easily-identified, unencumbered tone to make the point that typical listening of 16-bit is even harder to hear the shortcomings.
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As a post of mine earlier showed, and other tests I've done, it appears most sigma delta DACs are putting out correct bits at the correct level all the way down to the 23rd or 24th bit. However that output is buried usually in noise to a greater or lesser extent.
Now can we hear the bottom bits, I can think of no way that makes any sense to say we can. One might contrive various ways to boost up and listen to the lower couple of bits, but that isn't using it for music or anything practical. Self noise in microphones, and noise in recording venues is too high. One could make total electronic music, but even then listening to it you can't hear the lowest bits.
Now can we hear the bottom bits, I can think of no way that makes any sense to say we can. One might contrive various ways to boost up and listen to the lower couple of bits, but that isn't using it for music or anything practical. Self noise in microphones, and noise in recording venues is too high. One could make total electronic music, but even then listening to it you can't hear the lowest bits.
- Thread Starter
- #94
I'm glad we finally got the tones mystery figured out. I do want to say, their inclusion in the first post was just, "oh and there's this, in case anyone has less experience with the bottom bits and wants something to try something out." I didn't intend for it to be a big deal, so I'd just like to dial back possible expectations a little. Any conclusions, or lack thereof, from listening to these doesn't have any bearing on the other details of the discussion. Well, unless you're sure you hear the 24-bit... 
In my opinion you are wasting your time. If an audio person doesn’t understand this he has two choices. Trust you or not. If the latter, you ignore him. You can’t teach complex digital to analog transfer theory with just auditioning a file.
dc655321
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I think your demonstration is great, @earlevel.
Correct me if I misunderstand, but you're not out to teach electronics theory, only to demonstrate the reality (futility?) of signals that are -138dB rms.
@sarumbear - give "level_test_24bit.wav" about 120dB of gain and play it back (rms should then be -18dB). Hope you like vintage Nintendo?
Correct me if I misunderstand, but you're not out to teach electronics theory, only to demonstrate the reality (futility?) of signals that are -138dB rms.
@sarumbear - give "level_test_24bit.wav" about 120dB of gain and play it back (rms should then be -18dB). Hope you like vintage Nintendo?
dasdoing
Major Contributor
Blind testing a 60 dB Dynamic Range
Checking your listening room's noisefloor, online.
- Thread Starter
- #98
sarumbear, I write a blog to help people with some of these concepts (particularly DSP). In my opinion, it can help some people get over a hump in understanding, allowing further learning to come easier. I don't show anyone how to write a partitioned block convolution in C++, that might only let a few people work less. I don't derive an FFT, I show a different way to look at it that is more intuitive, then it's not a mental block for them. I've never earned a cent at it, I pay the hosting costs or equipment costs for making a video out of my pocket. It's just something I do in life. If I pursue and idea that someone else doesn't think is worth pursuing—well, I don't get paid for it either way, and I make my own judgements about it.
And when you say, "You can’t teach complex digital to analog transfer theory with just auditioning a file"—this never happened. I never told anyone all mysteries would be solved if they just audition this file. I don't understand why you go to this extreme. Eye charts don't improve your vision or teach you how the eye works—they are just a reference.
I did. However that is not the point of the exercise is it?
I respect what you do. Teaching is a noble thing to do.
Eyecharts work because they show you an error directly. Silent audio tracks does not. If we use your eye test analogy you produced an extremely black board and printed differing levels of black letters on it. You then ask people to switch the lights and see those lines.
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