# why not more 96kHz/24bit audio with Bluray



## gdstupak

Bluray has the capacity to handle 8 channels of 96kHz/24bit audio information. Why is most using 48kHz? And what bit rate is most common, 16bit? This is not much better than a standard CD at 44.1kHz/16bit.
Does it cost more to put higher resolution on Bluray?
Is it too much to ask for?

**EDIT** I was just thinking. Maybe not all receivers can handle the higher resolution? Maybe receivers are only required to support 48kHz?


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## mechman

I believe you answered your own question. :nerd:


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## Drudge

From what I have read,the main reason for not recording much at 96Khz is that it requires more hard drive space over 48khz and the increased sampling frequency is only a slight improvement that most of us would never hear,unless you have a dedicated HT with the proper acoustical control and noise isolation that would allow you to have a low enough noise floor(NC-15 or lower) to reap the benefits of 24Bit 48Khz,let alone 96Khz.Your hearing would have to be pretty good up to 20Khz as well.

The sound design,engineering,and mastering make more of a difference in the quality of the recorded sound than what you would technically get between 24bit 48Khz or 24bit 96Khz recorded audio.

The studios also like as much available space as possible for all those useless special features on Blu-ray discs.That's one of the reasons why you still have Dolby TrueHD or dts MA lossless compression used instead of the original uncompressed LPCM direct from the studio master because they still use less space.


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## gdstupak

Drudge said:


> The sound design,engineering,and mastering make more of a difference in the quality of the recorded sound than what you would technically get between 24bit 48Khz or 24bit 96Khz recorded audio.


I wholeheartedly agree with this statement. I do hear a difference with high resolution music that I download but often wonder how much of that has to do with the high resolution getting better engineering treatment.

Also, you've mentioned 24bit 48kHz several times, do you know if 24bit is common for Bluray?


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## Theresa

I really believe (but don't know) that bit depth is more important than sample rate. I hear no loss in quality even though the miniDSP's only sample at 48kHz. Perhaps someone younger who hadn't attended many rock concerts in their teens would be able to hear the difference.


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## Drudge

gdstupak said:


> I wholeheartedly agree with this statement. I do hear a difference with high resolution music that I download but often wonder how much of that has to do with the high resolution getting better engineering treatment.
> 
> Also, you've mentioned 24bit 48kHz several times, do you know if 24bit is common for Bluray?


Yes,most of the soundtracks on Blu-ray are 24Bit 48Khz.There is still the occasional 16Bit 48Khz soundtrack on some Blu-rays,but it's at the full CD quality bit rate and not the lossy AC-3/DD 448kbs that DVD used,so it's technically better.

I myself couldn't tell the difference between the 16Bit and 24Bit soundtracks on the Blu-rays that I've watched so far:huh:.


Rumor also had it that when Hi-Rez music discs were released that the mastering was different than the 16Bit redbook CD equivalents which accounted for a lot of the improvements and of course,there was the recorded in surround aspect as well:T.


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## SiriusBlack

I think it is all to do with cost, larger dynamic range (somehow) costs more :-(


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## Theresa

The question remains "could I hear the difference?" With my setup its a definite no because my miniDSPs have a 48kHz sampling rate. I don't hear any degradation with them so I probably wouldn't hear it anyway. But perhaps it takes a better trained ear for me. I can hear the difference between the 24 bit depth and 16 bit depth so who knows? I definately hear the difference with MP3s at 256 bits so perhaps I would hear that.


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## RTS100x5

Ive been a huge fan of the DVD-A for years. Heres my little piece of heaven. I do alot of audio mixing on my PC so I started researching on ways to remix my 2.0 files up to 5.1 / 96khz / 24 bit. CREATIVE LABS has a feature on some versions of their software called "SUPER RIP" which up sampled close to these specs but it took FOREVER to convert and would not work w existing files. Later a friend gave me a copy of ADOBE AUDITION and SURE CODE DTS and I started mixing files to 5.1 and encoding it to DTS format. Unfortunately each file had to be processed individually and encoded which was very tedious but the results were really good.. THEN quite by accident I found the SURROUND PROCESSOR feature in ADOBE. It exports any 2.0 file into WMA PRO 5.1/96k/24bit . Although ea file is processed individually, the encoding is very fast and I can tweak the audio levels withing the mix such as LFE and CC levels. And the results are fantastic. True they are not comparable to a 6 channel discreet mix like DVD-A but its NIRVANA compared to anything else Ive tried so far.... Its a simple process w excellent results and works w almost any file format....:sn:


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## gdstupak

Sounds like fun stuff to play around with. I've thought of up sampling but haven't really taken action on it yet.
Although I've downloaded some hi-rez music in 5.1 format, it has to be sent out of my computer as 2.0 because my M-Audio Sonica converter (USB to optical digital audio) can't handle the surround sound.
Maybe sometime soon I'll have to upgrade that.


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## lleb

ahh finally something that I can add to the shack and feel confident about posting. That's cool to hear that bluray is using 24 bit. 24 bit is definitely a huge step up as we have a bigger dynamic range to work with and keeps the noise floor down that much. 

It's unfortunate to have to work in 24 bit and then truncate the file to 16bit when dealing with CD mastering and DVDs. If your engineer knows what he's doing though a properly dithered 16 bit file should sound like a 20bit file (if it existed).

Higher sample rates help get rid of aliasing, and the only real need to use a higher rate would be when you're recording with mics in an environment that has lots of frequencies above our hearing range (lights, a/c units, etc) as these frequencies get reflected into our hearing range due to the limitations of our hardware (sounds like a mild hissing in the recording). Fortunately most preamps today have a cut off filter that chops those high frequencies (20kHz+) before they even get into the chain. 

Working at 24bit/48kHz is plenty. As others have said 96kHz is just more space on the computer.


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## gdstupak

Thanks for your input as I'm still learning about hi-res audio.
Before I read all of this info I was leaning toward buying more hi-res computer downloads instead of buying Bluray music discs. Just this weekend I rented the Bluray '_Johan Sebastian Bach: Brandenburg Concertos 1-6_' and am now wanting to buy it, but I was torn between buying the Bluray with the visuals, or buying the hi-res music download that was higher res. But now I'm starting to believe that the 24bit/48kHz on Bluray is hi-res enough.
Thank you all.


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## xslatex

16 bit audio contains 65,539 steps of resolution and has a dynamic range of 96 dB and 24 bit audio has 16,777,216 steps of resolution and 144 dB of dynamic range. A Blu ray is definitely capable of supplying 24 bit 96k audio so there's no reason why it shouldn't. The main reasons that it wouldn't be is because the sound design or dialogue may have been recorded at 24bit 48k, in which case they would have to up sample to match the 96k mark which would add a lot of artifacts that aren't actually there i.e. noise. The reason for 96k over 48k is because of the Nyquist Theorem, the sample rate should be twice the highest frequency recorded or created. 96k will capture a lot of harmonics and feeling that 48k won't which is why 24bit 96k would be desirable over 48k, but as for cost, it doesn't cost the corporation selling the movie anything extra to have 24 96 audio, but they might want to charge the consumer more money for that option.


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