[Zorlac]

Hey guys...

Why is it that there are DACs and Audio/Video receivers that show the "Sampling Rate" (i.e. 44.1kHz) of a source, but finding one that shows the "Bit Depth" (i.e. 16bit) seems to be impossible???

What is so special about analyzing the digital signal/frame to find out the Bit Depth????

Does anyone know of a DAC that shows both Sample Rate and Bit Depth?

 

[Ashirgo]

I have not seen any!

On the other hand, what explanation would you give to your questions yourself?

Regards,

Ash

 

[HeadLover]

I think they are some that show the KHZ (44.1 or 96 and so on)

 

[linuxworks]

at some point, it would almost make sense to have a very small fanless pc do that for you

create a Y such that the pc is listening in on the stream as well as your dac getting its feed from that Y connection (repeated; media bridge style).

the pc could easily determine this and then send the output to some parallel port leds or even an lcd display

as for why dacs don't display this, I think you have to read inside the spdif stream and and generate your own 'leds'. the dac chips and spdif receiver chips don't seem to have direct wires to show the SR and bit depth.

one project I built over 10 yrs ago had a PAL in between an spdif Rx and Tx pair. that chip 'picked out the bits' and sent some TTL signals so that I could display the actual SR:

at the time I built there, there was only 16 and 20bit audio in spdif and no one really cared much about 20

so there was no point in displaying the word size as it was always 16. however today, I would revisit that PAL (its opensource, actually) and see if it can detect word size as well as SR.

dacs and receiver chips don't directly give you this - and so that's why (I think) you don't see it in products.

 

[synaesthetic]

I was under the impression that lossy files did not have a bit-depth because they were no longer encoded in the time-domain like PCM.

 

[apatN]

Seriously.. Why?

 

[linuxworks]

Quote:

Originally Posted by synaesthetic /img/forum/go_quote.gif I was under the impression that lossy files did not have a bit-depth because they were no longer encoded in the time-domain like PCM.

lossy files started out as a lossless source, right?

the bit depth of the source is still there, sort of

depending on how good the lossy alg. is.

but you're right - once you lose bit-perfection, you've created an APPROXIMATION of the sample and so word lengths have no real meaning anymore. with variable bit-rate encoding, it makes even less sense.

 

[Zorlac]

Quote:

Originally Posted by linuxworks /img/forum/go_quote.gif at some point, it would almost make sense to have a very small fanless pc do that for you create a Y such that the pc is listening in on the stream as well as your dac getting its feed from that Y connection (repeated; media bridge style). the pc could easily determine this and then send the output to some parallel port leds or even an lcd display as for why dacs don't display this, I think you have to read inside the spdif stream and and generate your own 'leds'. the dac chips and spdif receiver chips don't seem to have direct wires to show the SR and bit depth. one project I built over 10 yrs ago had a PAL in between an spdif Rx and Tx pair. that chip 'picked out the bits' and sent some TTL signals so that I could display the actual SR: at the time I built there, there was only 16 and 20bit audio in spdif and no one really cared much about 20 so there was no point in displaying the word size as it was always 16. however today, I would revisit that PAL (its opensource, actually) and see if it can detect word size as well as SR. dacs and receiver chips don't directly give you this - and so that's why (I think) you don't see it in products.

Very cool! Where can I read up more on this open source project?

I'm sure there are a ton of folks that use a PC as their source that would love a small display to set on top of their DAC that would show info about the digital stream the PC is sending.

For instance, if you knew your source file (i.e. wav) was encoded as 2 channel, 16bit, 44.1kHz, then you could quickly view your display sitting on top of your DAC and verify that the digital SPDIF stream is bit perfect. The display would show 2 channel, 16bit, 44.1kHz.

Not sure why some think this is pointless. I know my AV receiver shows channels and sample rate, but bit depth (aka word length) is not shown. I would like to see some DACs that show all this info...or I would like to see some sort of device I can add to my audio chain that would sniff the digital frames and tell me this info (a sort of test or analyzer device I guess). I have searched online for something like this with no luck. May sound stupid, but if I had the no-how, I wouldnt mind creating my own product for the audiophile market. I cant be the only one that would be interested in such a thing.

 

[linuxworks]

Quote:

Originally Posted by Zorlac /img/forum/go_quote.gif Very cool! Where can I read up more on this open source project?

Index of /dat-heads/dsd

full schematics and PAL source. knock yourself out!

it would be great if someone who know PAL stuff (I don't, sadly) would update it to also show 96 and 192k as well as wordsize.

the PAL does pick out 'emphasis' although no one cares about that bit anymore.

the DSD is actually useful today even though DAT decks are mostly history, now. and SCMS is ignored by all

one place the DSD box worked for me is with my direct-tv tivo box with spdif out! that spdif is 'funky' in some way and most modern dacs seem to mute the signal and not pass spdif thru ;( home theater stereos can decode this funky spdif but most 'real' dacs cannot. enter the DSD - have it resend the spdif signal (fully receive it and fully resend it) and voila - all my dacs can now listen and decode the direct-tv audio (including the satellite music channels).

who'd have thought that a 1995 era box would be useful today for digital audio?

the led display hack was mine but the DSD design was a group effort on the old 'dat heads' mailing list. the schematic for the 2 digit display is not online and I'd have to search some OLD old disks to find it, though.

 

[Mik]

My Cambridge Audio 840C shows both bit depth and sampling rate for digital inputs.

 

[Zorlac]

840C is more like a source. I'm wanting to know stats for the sampling rate and bit depth just before the digital signal hits the DAC.

Good to know though. I wonder how Cambridge Audio gets this info?

 

[gregorio]

I'm not sure there is anything to be gained by having a display of bit depth because all the system could tell you is what the file format is, not how many bits have actually been used to create the music recording. The actual bits used is usually constantly changing (except in highly compressed/limited recordings) and never exceeds 11 bits on a commercially released recording.

G

 

[cafe zeenuts]

I'm using M-Audio Audiophile 192 -> coaxial -> 840C and i'm not sure it can really displaying the correct info.

Eg. playing a 24bit 176.4khz file from foobar2000, the DAC only showing 88.2 in sampling rate....

 

[Zorlac]

Quote:

Originally Posted by cafe zeenuts /img/forum/go_quote.gif I'm using M-Audio Audiophile 192 -> coaxial -> 840C and i'm not sure it can really displaying the correct info. Eg. playing a 24bit 176.4khz file from foobar2000, the DAC only showing 88.2 in sampling rate....

Sounds like you might be having issues with your PC sending a bit perfect signal to your DAC. Have you seen this thread?

http://www.head-fi.org/forums/f46/ea...torial-402765/

 

[BigTony]

My DAC gives no info, but my AVR does - so i can be sure that my SB3 output is right (it also shows the bit rate, depth etc on the.SB3). I don't typically use my pc hooked up to my DAC.