Confused noob--Apple lossless >192k, but DAC's accept only 192k?

[Schizoid]

Okay, probably a newbie question here. Most DAC's I've seen say that they accept signals up to 192k. For example, here's the sentence regarding the HeadRoom Ultra Desktop DAC's optical input:

"The UltraDAC accepts S/PDIF digital audio signals at standard rates and depths (44.1kHz, 48kHz, 96kHz, and 192kHz from 16 to 24 bit word depth) on both coax RCA and TOSLINK optical connections, . . . "

So, just getting into the whole high-end headphone thing, I converted one of my favorite CD's to Apple Lossless last night. The bit rates range from 638k to 887k. So if I play one of those tracks in i-Tunes with a DAC like the HeadRoom plugged into my optical out, what happens? Am I not getting the full benefit of Apple lossless? I'm sure there's something I'm missing here, but I'm not sure what.

Anyone want to help the newbie?

Thanks,
Sean

[koven]

rockbox your DAC to enable FLAC/OGG support

http://www.rockbox.org/twiki/bin/view/Main/WhyRockbox

[xxbaker]

The 44.1, 48, etc. numbers refer to the sample rate. That means there is a snapshot of the sine wave 44.1/48/(whatever number your specific file is) times a second. Well actually thousand times a second because it's kHz. The 'bit rate' that an ALAC (Apple Lossless Audio Codec) file gives you is in the units kbps (kilobits per second). A regular lossless file that's not compressed (from a cd of course)gives you 1411 kbps.

So you're comparing the bit rate of your song against the sample frequencies. What you need to do is look at the sample frequencies of your song (most likely all 44.1) to make sure that the DAC can play your files.

Hope that helps

[donunus]

Originally Posted by koven

rockbox your DAC to enable FLAC/OGG support

WhyRockbox < Main < TWiki

I dont understand how this relates to the question, plus you can't rockbox a DAC

Anyway, the 192 on the dac is the maximum input sampling rate of the transport and not the bitrate of a given file.

[Schizoid]

Wow, I'm dense. I should have known that something imported from a CD was going to have a sample rate of 44.1k and not been confused by the bit rate. This makes much more sense. I assume there must be other consumer sources like SACD or something like that which use the higher sampling rates accepted by the DAC's.

So, basically any good DAC will work with my files and sound better than using the analog line out of my Mac and allowing the Mac to do the conversion.

[donunus]

basically

[wilyodysseus]

Originally Posted by Schizoid

So, basically any good DAC will work with my files and sound better than using the analog line out of my Mac and allowing the Mac to do the conversion.

Yes.

The explanation provided here says: "Real sounds have frequencies and volumes. In order to measure real world sounds and represent them digitally, we have created sample rate and bitrate as digital’s audio qualities. Sample rate determines how analog frequencies are described digitally whereas bitrate determines how analog volume is described digitally."

That's something of a simplified version, but it gets the idea across.

A slightly more nuanced explanation here makes a good analogy between the bitrate of digital sound and the bitrate/color depth of digital images. An 8-bit image would be limited to 256 colors, while a 24-bit image would have 16,000,000 colors. Following the digital image analogy, I suppose the sample rate of digital audio would be like the resolution of a printed image. In an old newspaper or comic book, you can look closely and actually see the individual dots that make-up the image. That's low resolution. A glossy professional photo print would be high resolution.

To print a great picture from your computer, you need a good digital image file and a good printer. The digital image file must have a high resolution (many pixels per inch) and the printer must be able to reproduce that resolution by printing many tiny, tightly spaced ink dots per inch. Of course, each of those pixels in the digital image might be any one of millions of colors (color depth) and you need a printer of sufficient quality to be able to mix those millions of colors from just a few pigments (cyan, magenta, yellow).

So, yes, both a high bitrate and a high sample rate are important.

[Currawong]

If you're interested in higher bit-rate music, you'd have to buy it from somewhere like Linn Records, HDTracks or the like. I haven't found the benefits to be as huge as I hoped, in that, other components make much more of a different, starting with one's headphones.

[Schizoid]

Well, I've got a pair of Audio Technica ATH-AD900 phones coming my way. Hopefully I'll like them. I'm upgrading from an old pair of AKG K 401's that my new dog chewed up!

Currently, I run the 1/8" audio line out from my Power Mac (older G5) into a small Yamaha mixing board and then run my phones off the mixer's headphone output. I use the mixer as I frequently practice along with recordings with my bass guitar.

I'd like to get a stand-alone headphone amp, but my problem is how to incorporate my instrument into it. A solution that a lot of bassists use is the Cafe Walter HA-1A (HA-1A Headphone Practice Amplifier), but I'm not sure if that's any better than using the mixer.

Opinions?

[Currawong]

What benefit are you looking to gain with a headphone amp?

[Schizoid]

I just thought it might have higher fidelity than the cheap mixing console. Frankly, I was pretty happy with the sound from the mixer, but I have nothing to compare it to. I guess I need to know where the next weakest link in my chain is since I've upgraded my phones. Is using the DAC capabilities of the Mac? Using a cheap 1/8" to RCA cable between the Mac and the mixer? The mixer itself?

[apatN]

I have a question regarding 192khz as well. I have a nice Daft Punk vinyl rip that is in 192khz. I get this message in Foobar (bit-perfect/WASAPI):



Clearly my DAC can't handle the 192khz so I am looking for the best way to change the rips to 96khz. Can anyone help me out?

[wilyodysseus]

Originally Posted by apatN

Clearly my DAC can't handle the 192khz so I am looking for the best way to change the rips to 96khz. Can anyone help me out?

I was under the impression that the DacMagic does support 192 (but maybe not if you're using the USB interface?).

I'm on a Mac, so I'm not familiar with Foobar, but what you want to Google for is something like "downsample foobar" or "downsample flac".

[Podtweaker]

Originally Posted by Schizoid

Okay, probably a newbie question here. Most DAC's I've seen say that they accept signals up to 192k. For example, here's the sentence regarding the HeadRoom Ultra Desktop DAC's optical input:

"The UltraDAC accepts S/PDIF digital audio signals at standard rates and depths (44.1kHz, 48kHz, 96kHz, and 192kHz from 16 to 24 bit word depth) on both coax RCA and TOSLINK optical connections, . . . "

So, just getting into the whole high-end headphone thing, I converted one of my favorite CD's to Apple Lossless last night. The bit rates range from 638k to 887k. So if I play one of those tracks in i-Tunes with a DAC like the HeadRoom plugged into my optical out, what happens? Am I not getting the full benefit of Apple lossless? I'm sure there's something I'm missing here, but I'm not sure what.

Anyone want to help the newbie?

Thanks,
Sean

I think you may be confusing Khz w/ Kbps they are two different things. If it was a CD that you converted to Apple Lossless than the bit rates you are seeing are within the AL range . While the files are lossless it is compressed lossless that is being uncompressed at the playback stage. A CD is 16b/44.1khz which if were to leave uncompressed translates to 1411kbps,Apple Lossless is compressing this to the files sizes you are seeing. For an actuall 24bit/192khz file you would see a 9216kbps(Yup, that's right 9k) file size. The real question though do those Apple Lossless files sound pretty good to you ? Depending on your musical tastes & equipment you have the capabilities to play back larger file sizes should you decide to do so,but for CD material you are absolutely seeing what is normal for what you've chosen to do! Don't get too wrapped up in the numbers they are just guide lines! Enjoy!

[krmathis]

Originally Posted by apatN

I have a question regarding 192khz as well. I have a nice Daft Punk vinyl rip that is in 192khz. I get this message in Foobar (bit-perfect/WASAPI):

http://i12.photobucket.com/albums/a2...g?t=1243761209

Clearly my DAC can't handle the 192khz so I am looking for the best way to change the rips to 96khz. Can anyone help me out?

Looks like a file playback issue to me.
Are you sure Foobar2000 can handle the bit-depth and sample-rate, with that codec/format (whatever it is)?