Looking for some basic explanations- Cambridge DAC

[krelldog]

Please don't flame me...computer audio is relatively new for me, but I'm loving the convenience. If anyone can answer some basic questions in terminology I can understand I would be very appreciative.

 

System: HP/Laptop/USB 3.0 with J River installed- USB A-B (Pangea 5-meter cable) connected to a Cambridge Azur 851 D-single ended cable to a Parasound Halo Integrated -Martin Logan Theos. All music files on my hard drive are 320 KBPS.

 

1. Out of the box the Cambridge had built in software for USB Class 1. When I played a music file on JRiver the Cambridge displayed 96khz. I was very impressed with the sound. However the Azur also offered USB Class 2 operation that required a driver that I also downloaded. The sound with USB 2 also sounded very good, however it displayed 44.1 khz.

 

My questions are- The unit advertises it can accept up to 24 bit 192 khz. How do I achieve this bit rate? Do I want to achieve this bit rate?

 

I know this is complicated...but I would like to make sure I'm getting the full performance from my DAC.

 

Any and all help would be very appreciated. Thanks in advance for your help.

 

krelldog

[CatManDo]

If you want high resolution sound, you must have high resolution source material. You say all your files are "320 KBPS", which means MP3 files, which are in a standard resolution (usually 16/44, but in some case 16/48) but more importantly they are in a lossy compression format.

 

What is FLAC? The high-def MP3 explained - CNET

 

It makes no sense to discuss about the playback resolution at that point, considering the limitations of the source material.

 

The reason why your Cambridge received a 96Khz signal with USB Class 1 was that your computer was upsampling the signal from 44Khz, the true sampling rate of the files.

 

With your high quality equipment, it would be worth switching to lossless files (usually in FLAC format), which means re-ripping your CDs or re-downloading files in lossless quality, if available.

[One and a half]

Great advice there Claude.

 

Ideally, like to add, a CD's sampling rate is 44.1kHz. With choice of players, you can upsample to higher rates, but the rate needs to be in multiples of the original.

 

For CD thus would be 44.1 (no oversampling), 88.2, 176.4.

For 48kHz base files as often recorded on the DAT standard, the rates are 96kHz and 192kHz.

Generally, the higher rates allow for a better filter to be used in the DAC, or the playback software. It has nothing to do with frequency response extended to way past human limits.

 

Sad to say the 320 kbs files have valuable information that's already lost and can't be recovered. You have a good foundation to listen to with your equipment and agree with Claude, the source material improvement is worthwhile and is the cheapest upgrade!

[17629v2]

You also need to know the difference between lossy and non-lossy data compression. Data compression in general, is used to fit more information on a disk than it would normally be able to hold. MP-3 is lossy compression. That means when you "rip" a cd, for example, you lower the actual quality of the music file to get more information on the disk. Think of it in terms of video resolution on computers. Sometimes you have to lower the resolution on a computer program to get a better frame rate because your computer and/or video card may not be up to the task. Switching to a lower resolution makes makes the app usable.

 

Non-lossy is also data compression. Its just not as extreme as lossy. That means, even though you compress the data, its done in such a way so you get all of the info back when you play it. Non-lossy is what they use on computer programs. If you don't recover 100% of the code that makes up a program, it won't work. The downside to non-lossy compression, is that the file sizes are much bigger than something like an MP-3.

 

One thing that's very important to remember, is when you convert music to a lossy format like MP-3, the information removed from the file to compress the data is lost and can't be recovered. That's why no one recommends MP-3 for serious listening. You use it when you are trying to load an iPod (or similar device) with music and are willing to sacrifice some sound quality. For audiophile use, you always wan't to use non-lossy compression. The most common format, by far, is FLAC.

 

"My questions are- The unit advertises it can accept up to 24 bit 192 khz. How do I achieve this bit rate? Do I want to achieve this bit rate?"

 

This is where it can be a little confusing. CD quality is 16 bit 44 khz. Always remember that you can't get more than what you start out with. The best sound you can get from a CD is CD quality at 16/44. You can, however, rip and playback a CD at 24/192. The reason for this, is your playback software can make the blank space that separates 16/44 from 24/192 look like its filled with information. Simply put, it tricks your computer into playing a lower resolution music file at a higher resolution. That's called up-sampling. The main reason for up-sampling is that, due to the extra processing, up-sampled music does sound a little different. Its kind of like using a tone control, or an eq. Its still the same basic sound quality, you're just tweaking it a bit to get a different sound.

[krelldog]

Great information....Thank You. Each of these responses has been extremely helpful. I'm eager now to download some Flac files to see what the difference is.

[17629v2]

Great information....Thank You. Each of these responses has been extremely helpful. I'm eager now to download some Flac files to see what the difference is.

 

If you're going to experiment, you can just rip one of your own CD's. I like this way better because you know exactly where the files came from. Sometimes, when you download, the music may have some processing or replay gain added to it. There may even be some uncertainty as to whether you're getting a re-master. If you miss any of those details, it can result in some big mistakes. You can use jRiver for ripping and transcoding.

[Panelhead]

Another item is playback software. The results from using software to upsample 44.1/16 and playback are amazing.

It is complicated, the results are worth the effort. HQPlayer is one great example. The results can be amazing with just CD quality files.