Skip to main content ↑ ↓

Notice

Please note that most of the software linked on this forum is likely to be safe to use. If you are unsure, feel free to ask in the relevant topics, or send a private message to an administrator or moderator. To help curb the problems of false positives, or in the event that you do find actual malware, you can contribute through the article linked here.
Topic: Dynamic range in high fidelity systems (Read 45782 times) previous topic - next topic
0 Members and 1 Guest are viewing this topic.

Dynamic range in high fidelity systems

I was wondering what is the typical amplifier dynamic range and signal to noise ratios for a quality high fidelity audio system for input and oput?
I have read in the specifications of a Creative amplifier speaker a 75 db signal to noese ratio, so I guess it more than enough for 16 bit quatization?
even if the external noise was zero the low level signals would be buried in the amplifier's backgroud noise- right?

Dynamic range in high fidelity systems

Reply #1 –
Quote from: enry2k on
I was wondering what is the typical amplifier dynamic range and signal to noise ratios for a quality high fidelity audio system for input and oput?
I have read in the specifications of a Creative amplifier speaker a 75 db signal to noese ratio, so I guess it more than enough for 16 bit quatization?
even if the external noise was zero the low level signals would be buried in the amplifier's backgroud noise- right?

CD has up to 96 db signal to noise.

Paul

     
"Reality is merely an illusion, albeit a very persistent one." Albert Einstein

Dynamic range in high fidelity systems

Reply #2 –
Do quality audio systems reach 96 db signal to noise ratios?
Do microphones amplifiers reach similar signal to noise ratio?
Is the noise floor of the microphone amplifiers a built-in dither?

Dynamic range in high fidelity systems

Reply #3 –
Quote from: enry2k on
Do quality audio systems reach 96 db signal to noise ratios?
Do microphones amplifiers reach similar signal to noise ratio?
Is the noise floor of the microphone amplifiers a built-in dither?

Yes........... one model of many Yamahas for one company.


Signal to Noise Ratio (IHF-A Network)
PHONO (2.5 mV) to Front L/R
[U.S.A. and Canada models] .................................................... 80 dB or more
PHONO (5 mV) to Front L/R
[Australia model] ..................................................................... 81 dB or more
[Other models] ......................................................................... 86 dB or more
CD, etc. (250 mV) to Front L/R ............................................. 100 dB or more
"Reality is merely an illusion, albeit a very persistent one." Albert Einstein

Dynamic range in high fidelity systems

Reply #4 –
Quite often the limiting factor is the listening room's "S/N ratio". (I.e. the sound pressure level of the background noise limits the practically usable dynamic range).

Isolating headphones may be able to produce a better dynamic range that rivals CD-audio when the playback volume is set to very loud, but then the peak volume level may be dangerous for hearing.

Dynamic range in high fidelity systems

Reply #5 –
So 24 bit quantization is really only useful for processing audio, it is a waste for the final product.
Is  there any successful 16 bit versus 24 bit ABX Test?
Nobody is able to distinguish between the two signals right?

What about the sampling frequency?
I have read that the human ear is almost insensitive to phase shifts. So a 44.1 khz sampling frequency should sound the same than a 88.2 khz frequency. Is this true?

Dynamic range in high fidelity systems

Reply #6 –
Many mic pre-amps and some power amplifiers have S/N performance approaching 120 dB. A/D and D/A converters are around 100 dB. I agree with Alex, the limiting factor is almost always your room. You're lucky if you get 60 dB between "silence" and hearing damage.

Dynamic range in high fidelity systems

Reply #7 –
Quote from: Notat on
Many mic pre-amps and some power amplifiers have S/N performance approaching 120 dB. A/D and D/A converters are around 100 dB. I agree with Alex, the limiting factor is almost always your room. You're lucky if you get 60 dB between "silence" and hearing damage.


Therefore to hear even the lowest sound you should use isolated headphones in a very quiet room.
Is it possible to perform reliable ABX tests in such optimal conditions?

Thank you for the interesting replies guys!

Dynamic range in high fidelity systems

Reply #8 –
In terms of equipment you can get a lot of dynamic range pretty easy. For not a ton of money you can have equipment that is really 100dB SNR or better. Now of course as you add more pieces in to the chain the over all noise level goes up. You can even find equipment around or a bit better than 120dB though it usually costs a fair bit.

As others mentioned, the room can be a rather big limit. 120dB is the threshold of pain and thus generally a good "absolute max". As a practical matter, you'd be advised not to go over 100dB for long periods, and really not over 90dB for long periods. Now your room is going to have some noise, unless you live in an anechoic chamber. 30dB is probably the realistic minimum you'll find in a quiet house with electronics on (they make noise) and 40dB would certainly be fairly common.

That means you are talking somewhere in the realm of 50dB-70dB between your room's noise level and the level you ought to be listening at and probalby not more than 90dB total.

However, that doesn't mean that a high SNR system is necessarily worthless. For one, if the noise level is too high, you may be able to hear it during quiet passages or silence. I had this with my system when using DTS Interactive encoding from my computer. When set to reference volume levels, I could hear a quiet hiss from the speakers. It wasn't much, but it was noticeable. Switching over to HDMI fixed that.

Also in your room, the noise floor is just the level at which the noise is. You can hear things under it by at least 10dB, probably more. In some electronics, the noise floor is a pretty hard limit, any signal lower is just gone. As such it can be useful to have equipment that has a noise level a good bit below the noise in your room.

As a practical matter though, get any decent equipment and it isn't likely to be a problem.

As for higher frequencies, I don't know that there's been any definite research done but I'd say very likely not. All the best knowledge and testing on human hearing says it caps out around 20kHz if we are lucky, and below that in most of us as we get older. I've seen no reliable tests showing we can perceive things above our hearing limit through other means. In my informal testing, I've never been able to hear a difference.

Also there's the fact that you don't find a lot of speakers that go significantly past 20kHz. Good ones will usually go a bit above it but not much. Finding ones that go up to the 40-50kHz range are somewhat rare.

As for optimal ABX conditions sure, you can find places like that. An audiologists's office would be one. Of the tests they do on your hearing, one is the threshold of hearing. That means they have equipment that'll produce sound down at around 0dB and a room quiet enough for that to be useful (with headphones on). Usually they'll tests the basics like making sure you can hear a tone in each ear and so on, then test speech recognition. If that works they'll find the threshold of your hearing with tones (you indicate when you start hearing them). Then they test speech recognition at that threshold. Ideally, it is 0dB (0dB SPL is chosen as such because it is normally the threshold of hearing) though it usually goes down as you get older (mine is 10dB).

So in a nutshell my opinion is don't worry about higher frequency stuff, do spend enough to get high SNR equipment but don't go crazy trying to get amazingly high SNR.

Dynamic range in high fidelity systems

Reply #9 –
Thank you for you valuable considerations.
Therefore do you agree ABX test of CD versus DVD-A is not possible because you coun't hear any difference?

Dynamic range in high fidelity systems

Reply #10 –
Quote from: enry2k on
Thank you for you valuable considerations.
Therefore do you agree ABX test of CD versus DVD-A is not possible because you coun't hear any difference?


Depends on the conditions.  Such tests can be cooked to show whatever you like.  But under realistic listening conditions this is unlikely.

Dynamic range in high fidelity systems

Reply #11 –
Quote from: Sycraft on
Ideally, it is 0dB (0dB SPL is chosen as such because it is normally the threshold of hearing)


Just a small correction. 0 dB SPL is set rather arbitrarily to 20 microPascals sound pressure level because the 20 uPa value is close to average threshold at 1 kHz, and 20 is a nice and easy to remember number, nicer than 12.6, or 9, for example. Typically, the threshold of hearing for a healthy young person is at minus a few dB SPL at 3-4kHz.
http://en.wikipedia.org/wiki/File:Lindos1.svg
Ceterum censeo, there should be an "%is_stop_after_current%".

Dynamic range in high fidelity systems

Reply #12 –
Quote from: pawelq on
Quote from: Sycraft on
Ideally, it is 0dB (0dB SPL is chosen as such because it is normally the threshold of hearing)


Just a small correction. 0 dB SPL is set rather arbitrarily to 20 microPascals sound pressure level because the 20 uPa value is close to average threshold at 1 kHz, and 20 is a nice and easy to remember number, nicer than 12.6, or 9, for example. Typically, the threshold of hearing for a healthy young person is at minus a few dB SPL at 3-4kHz.
http://en.wikipedia.org/wiki/File:Lindos1.svg




I have tested the frequency response of my own ears genereting tones using Adobe Audition. Sadly I am no longer able to hear pure tones above 16 khz, I am 40 years old.
There is a lange waste of bits in a linear PCM system since the full dynamic range is reached only in the 1 to 4 khz range. At 10 khz for instance, it will be much lower.

Dynamic range in high fidelity systems

Reply #13 –
Quote from: Mike Giacomelli on
Quote from: enry2k on
Thank you for you valuable considerations.
Therefore do you agree ABX test of CD versus DVD-A is not possible because you coun't hear any difference?


Depends on the conditions.  Such tests can be cooked to show whatever you like.  But under realistic listening conditions this is unlikely.


Does this mean that some differences can me revealed by the tests in optimal conditions?
For example if I compared bit to bit identical tracks, no statistical differencies should be found.

Dynamic range in high fidelity systems

Reply #15 –
Very interesting!

Thank you

Dynamic range in high fidelity systems

Reply #16 –
Quote from: enry2k on
Thank you for you valuable considerations.
Therefore do you agree ABX test of CD versus DVD-A is not possible because you coun't hear any difference?


Well if you ABX a normal DVD-A and CD you'll hear a major difference. However, it isn't because of the extra bits, it is because DVD-As are normally properly mastered, with dynamic range intact, whereas CD they like to squash down in to oblivion. I buy DVD-As when possible in a large part due to that reason. Also, many DVD-As are surround, which is another reason I buy them.

As for a case where the DVD-A is stereo and the CD is the same mastering. I'm betting probably not in most cases.

24-bit in terms of reproduction systems isn't so much a necessity as an insurance situation. There are conceivable situations where your dynamic range is such that 16-bit starts to cause problems. 24-bit goes well beyond not only what we can hear, but beyond what it seems we will ever be able to get electronics to do. The inherent noise of electrons bouncing around in the transistors is higher than the 24-bit noise floor.

So 24-bit means that you aren't going to run in to excess noise from quantization or dithering, and aren't going to have to sacrifice dynamic range in any situation.

Insurance.

However if the question you are after is should you try DVD-A the answer is most certainly yes if there's music on it you like. Surround music is very impressive IMO and having proper dynamics is just vital. Never mind the bit/sample reasons, get it because the music on it is done for listening to on a nice system, not compressed to be loud on a portable player.

Dynamic range in high fidelity systems

Reply #17 –
Quote from: enry2k on
Quote from: Mike Giacomelli on
Quote from: enry2k on
Thank you for you valuable considerations.
Therefore do you agree ABX test of CD versus DVD-A is not possible because you coun't hear any difference?


Depends on the conditions.  Such tests can be cooked to show whatever you like.  But under realistic listening conditions this is unlikely.



Right. The problem is the source material and the listening room. As others have pointed out setting up an audio system with about 100 dB dynamic range through the electronics is definately doable with reasonable resources.  The problem comes in when you try to go 100 dB SPL 20-20 KHz above the background noise in a typical listening room with background noise of maybe 45 dB SPL.  Generating 145 dB SPL in a listening room is no mean trick, but listening to it in comfort is mission impossible. You might physically hurt your internal organs in the process! :-(

If you go for a room with backround noise at say 10 dB SPL, the room is either going to be in a very secluded place, or your expenses for building the room will be very significant. JJ has talked in the past about the problems that no less than AT&T had building a truely quiet listening room. Got  a AT&T type budget? Be my guest! And that room with 10 dB SPL noise still forces you to listen to 110 dB peaks if you want to hear the benefits of that 100 dB dynamic range. The ear is most sensitive at more like 85 dB for most people. So, you still won't be listening at your peak.

The widest dynamic range source material I've ever found for regular commerical sale had about 85 dB dynamic range. Doing that without fudging is no mean trick, either. And, it is still 15 dB shy of the century mark.  A typical recording made by fairly natural means has maybe 70 dB dynamic range.

Quote
Does this mean that some differences can me revealed by the tests in optimal conditions?


Well, now you know what those optimal conditions may involve. Of course you can do things with earphones and the like. Thing is, earphones aren't perfect either. You start hearing noises that your head makes because you are alive. Blood pulses through you blood vessels and the like.  Noise from trivial movements of your head comes in mechanically through the headphone cable.  Being really quiet is not fun.

Quote
For example if I compared bit to bit identical tracks, no statistical differencies should be found.


If you compare a 24 bit recording of most things to a 16 bit recording of the same thing, at the bit level, differences will abound to say the very least.  Don't underestimate our ability to measure differences that we can't hear!

The fun comes when you actually try to hear the difference. ;-)

Dynamic range in high fidelity systems

Reply #18 –
Quote from: Sycraft on
Quote from: enry2k on
Thank you for you valuable considerations.
Therefore do you agree ABX test of CD versus DVD-A is not possible because you coun't hear any difference?


Well if you ABX a normal DVD-A and CD you'll hear a major difference. However, it isn't because of the extra bits, it is because DVD-As are normally properly mastered, with dynamic range intact, whereas CD they like to squash down in to oblivion. I buy DVD-As when possible in a large part due to that reason. Also, many DVD-As are surround, which is another reason I buy them.


The right way to do an experiment like this is to take that fine high quality 24 bit source, and dither it down to 16 bits. Then you know for sure that the basic source material was the same.  Been there, done that, no joy - for reasons described in a post I just made.

Dynamic range in high fidelity systems

Reply #19 –
Quote from: Arnold B. Krueger on
The right way to do an experiment like this is to take that fine high quality 24 bit source, and dither it down to 16 bits. Then you know for sure that the basic source material was the same.  Been there, done that, no joy - for reasons described in a post I just made.


I understand, I'm just not sure what the original poster was going for. If the question is "Can I ABX 24-bit vs 16-bit of the same material?" the answer is most likely no in normal situations. However if the question is "Can I hear a difference between off the shelf DVD-A and CD?" the answer is most certainly yes. I highly recommend anyone who is in to good much check out DVD-As (if their chosen styles of music are on DVD-A) because of the better production that is done. Only downside is that is can make the brickwall limited CDs of today even harder to tolerate ><.

enry, if you want to play with some 24-bit/16-bit comparisons I've posted a few files you can listen to. These are done so that the only difference if the sample size, and done with proper dithering so the 16-bit files should retain as much dynamic range as possible. I can't post any DVD-A vs CD comparisons since the music is copyrighted to show you the difference in terms of production.

Dynamic range in high fidelity systems

Reply #20 –
Quote from: Arnold B. Krueger on
Only downside is that is can make the brickwall limited CDs of today even harder to tolerate ><.

The brickwall above what you can hear. How about that Brickwall in the ears.

Paul

     
"Reality is merely an illusion, albeit a very persistent one." Albert Einstein

Dynamic range in high fidelity systems

Reply #21 –
Quote from: Paulhoff on
Quote from: Arnold B. Krueger on
Only downside is that is can make the brickwall limited CDs of today even harder to tolerate ><.

The brickwall above what you can hear. How about that Brickwall in the ears.

Paul

     


Sorry, perhaps I'm using confusing terminology. I don't mean the anti-aliasing filter, I mean the dynamic range limiting. They love to grab a peak limiter and crank it up to "insane" and then a few more DB past there. Makes the dynamics go away and the peak view look like a solid wall.

Heck some CDs they do it to the point you can hear a bit of clipping. The loudness wars on CDs is really bad. However, it doesn't seem to affect DVD-A, at least the ones I've bought. They properly mastered, with dynamic range intact.

Dynamic range in high fidelity systems

Reply #22 –
thank you for the latest posts!
great discussion!
Don't you think that it would be interesting to use the following special sample signals to esperience the full dynamic range of a digital system?

a 2.5 khz low level square wave obtained by swiching on and off only the least significant bit during half period, in other words the lowest possible square wawe.
a 2.5 khz high level square wave obtained by switching all the wodcode bits on and off during half period. in oher words the highest possible square wave.

These samples can be created manipulating a blank linear pcm wav sample in a hexadecimal editor.

I have chosen 2.5 khz frequency because it is positioned within the highest sesitivity region of the human ear.

You could experiment the low level square wave in different volume and noise coditions compared to the loudest signal level.


What do you think about?

Dynamic range in high fidelity systems

Reply #23 –
Quote from: Sycraft on
However if the question is "Can I hear a difference between off the shelf DVD-A and CD?" the answer is most certainly yes. I highly recommend anyone who is in to good much check out DVD-As (if their chosen styles of music are on DVD-A) because of the better production that is done.
Sometimes. Not always. Audiophile labels usually make the CDs as good as possible too. Non-audiophile levels have been known to trash the DVD-A / SACD too!

So while sometimes it's a good way of getting something that's been produced with more care, other times it's a good way of spending more money and receiving a far less convenient product!

Cheers,
David.

Dynamic range in high fidelity systems

Reply #24 –
Quote from: enry2k on
thank you for the latest posts!
great discussion!
Don't you think that it would be interesting to use the following special sample signals to esperience the full dynamic range of a digital system?

a 2.5 khz low level square wave obtained by swiching on and off only the least significant bit during half period, in other words the lowest possible square wawe.
a 2.5 khz high level square wave obtained by switching all the wodcode bits on and off during half period. in oher words the highest possible square wave.

These samples can be created manipulating a blank linear pcm wav sample in a hexadecimal editor.

I have chosen 2.5 khz frequency because it is positioned within the highest sesitivity region of the human ear.

You could experiment the low level square wave in different volume and noise coditions compared to the loudest signal level.


What do you think about?

You should use dither, and choose the lowest level signal that's still audible against the noise floor. It'll most likely be lower than your "lowest possible square wave".