Support and General Use > Audio Playback, Database and Playlists
Enabling 24bit-44.1/48/88.2/96khz playback - iAudio and others?
preglow:
--- Quote from: mcmurray on October 15, 2007, 11:39:11 AM ---Thanks for chiming in preglow. Â Just one stupid question, why is the DMA transfer limited to 16bits? Â
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AFAIK just a pure hardware limitation. Nothing more to it, Motorola just didn't put in a possibility to use higher bit depths with DMA.
mcmurray:
--- Quote from: saratoga on October 15, 2007, 02:26:58 PM ---
Be careful here. No concert recording is going to have even close to 16 bit resolution, so these should probably be kept at 16 bit. Likewise, vinyl cannot do 16 bit either, so 24 bit is silly. DVD-V is just AC3, DTS or MP2 lossy compressed audio, so theres no point in 24 bit playback. That really just leaves DVD-A, and even that is not always 24 bit.
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I'm going to respectfully disagree with you on those points. I have compared the 24bit FLAC concert recordings with the 16bit FLAC and the 24bit sounds a lot clearer and defined than the 16. I'm happy to upload some examples to megaupload for your perusal.
There are also many DVD-Video discs that contain 24bit LPCM audio (although only a small percentage). 99% of the DVD-Audio discs I have seen contain 24bit 2ch audio, some of which store the 2ch audio on the DVD-Video section. (dualdisc however is a different story, with all sony releases 16bit only). And with the recent introduction of MVI discs with compulsory 24bit stereo, we have more reason to consider high res playback.
As for the vinyl rips I haven't ripped one yet, but through my system vinyl sounds better than it's CD counterparts, worth archiving to 24bit imho.
Anyway it seems that getting the iAudio x5 to play 24bit isn't going to work at the sample rates I require. However I am shortly going to begin hardware design on a non-portable rockbox based audiophile dap that meets my needs.
saratoga:
--- Quote from: mcmurray on October 16, 2007, 02:13:36 AM ---
I'm going to respectfully disagree with you on those points. I have compared the 24bit FLAC concert recordings with the 16bit FLAC and the 24bit sounds a lot clearer and defined than the 16. I'm happy to upload some examples to megaupload for your perusal.
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Well, I'm sorry, but its not possible to exceed 16 bit resolution during concert recording. Just think about what that would require. You'd need ~100dB above the noise floor. Ever been to a concert with less then 40dB ambient? I haven't. Even at that level, you'd need peaks 20dB above the threshold of pain. This doesn't happen. Most of the concert recordings I have would fit in 8-12 bit nicely.
--- Quote from: mcmurray on October 16, 2007, 02:13:36 AM ---There are also many DVD-Video discs that contain 24bit LPCM audio (although only a small percentage). 99% of the DVD-Audio discs I have seen contain 24bit 2ch audio, some of which store the 2ch audio on the DVD-Video section. (dualdisc however is a different story, with all sony releases 16bit only). And with the recent introduction of MVI discs with compulsory 24bit stereo, we have more reason to consider high res playback.
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Yeah but thats mostly lossy stuff. Even MVI is usually AC3 or DTS I think. Not much point in 24 bit for that.
--- Quote from: mcmurray on October 16, 2007, 02:13:36 AM ---As for the vinyl rips I haven't ripped one yet, but through my system vinyl sounds better than it's CD counterparts, worth archiving to 24bit imho.
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Worth archiving maybe, but certainly not playing back. They don't even have 16 bit resolution. You gain nothing from 24 bit playback of a < 16 bit source. Thats how it works. You need the whole chain to have 24 bit or equivalent accuracy, and if its coming from AC3, DTS or vinyl you're not getting that. You can't just take a 16 bit or even lower equivalent source and expect to gain
pabouk:
--- Quote from: saratoga on October 16, 2007, 05:16:03 PM ---Well, I'm sorry, but its not possible to exceed 16 bit resolution during concert recording. Just think about what that would require. You'd need ~100dB above the noise floor. Ever been to a concert with less then 40dB ambient? I haven't. Even at that level, you'd need peaks 20dB above the threshold of pain. This doesn't happen. Most of the concert recordings I have would fit in 8-12 bit nicely.
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I think that the quantization noise of the 12 bit recording will be easily noticeable and distinguishable from the ambient noise. Please do not mix quantization and ambient noise. They are very different things. The ambient noise is a part of the recording (EDIT: which is usually desired).
I do not have any equipment to test resolutions above 16 bit and I also think that I do not have good ears but I think that some people can benefit from higher resolutions - at least in recordings with high dynamic range (classical music).
--- Quote from: mcmurray on October 15, 2007, 01:55:59 AM ---24bit doesn't just provide a better snr than 16 bit, it also provides more resolution (16777216 discrete levels for 24bit as opposed to 65536 levels for 16 bit i.e. much closer to analogue performance), and a higher signal to quantization distortion ratio. Even though the SNR may not be limited by 16bit, the higher resolution will still be noticeable (in the same way that vinyl provides very good resolution in spite of poor SNR).
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The resolution directly implies one part of the SNR. See quantization noise.
Mcmurray, which equipment do you use for listening to 24 bit recordings? Did you do blind ABX test? I am afraid that you are deceived by a placebo effect or the 24 bit recording is different in comparison to the 16 bit recording - for example uncompressed dynamic range or other differences in mastering. Please try to convert the 24 bit recording to 16 bits and then do the ABX test between the original 24 bit recording and the one downsampled to 16 bits. For both things you can use foobar 2000.
lazpete:
--- Quote from: mcmurray on October 15, 2007, 01:55:59 AM ---Im using and listening to ripped albums at 24 bit 96 khz in flac on my sansa e200. Large but fantastic...
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You're listening to our somewhat poor resampler. You'd get much higher fidelity out of CD audio I'm afraid. It seems to me you really need to sit down and ABX some of your tracks at 24 bit and at 16 bit. I think you'll be surprised what the difference really is if you think our resampler sounds "fantastic" :)
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Did a resampling of the Joni Mitchell album Blue, to 16 bit 44.1 khz, in foobar and I agree . It is accualy better on the sansa now.
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