Upper frequency for HD audio?

[rmcohen]

Hi,

Could someone please tell me what frequency level my speakers should be able to reach to take full advantage of the new HD audio formats on Blu-ray and HD-DVD discs? For example, my speakers can go as high as 20kHz, which I thought was the upper limit for human hearing. However, newer speakers can go a lot higher. And, with the new lossless audio formats on the new movie discs, I wanted to be sure I wouldn't be missing out.

Thanks.

 

[supervij]

Missing out on frequencies you can't hear? Seems moot to me. Don't worry about those speakers that can go beyond 20 kHz. You're doing just fine with your current speakers, frequency-wise.

cheers,
supervij

 

[mtrycrafts]

Hi,

Could someone please tell me what frequency level my speakers should be able to reach to take full advantage of the new HD audio formats on Blu-ray and HD-DVD discs? For example, my speakers can go as high as 20kHz, which I thought was the upper limit for human hearing. However, newer speakers can go a lot higher. And, with the new lossless audio formats on the new movie discs, I wanted to be sure I wouldn't be missing out.

Thanks.

Yes, as sup mentioned, not to worry. The new HD audio is just lossless, unlike the DD or DTS that is on DVDs today.
By the way, you'd be lucky if you Can even hear 20kHz

 

[skizzerflake]

If you are over 20 or ever listened to loud music, don't worry too much about frequencies over 20K. There is a school of thought that if you speakers can kick out 25K, then 15 or 20 will be produced with "ease" or "speed". I take this stuff with somewhat of a grain of salt. The measurement of speakers is dark art and depends greatly on the exact nature of the listening environment and the positioning of the equipment in the room. Numbers from manufacturers tend to be self-serving and frequently refer to an anechoic environment, which nobody in the real world actually has. The best way to evaluate them is to listen in some sort of decent room that is somewhat like where you will use them. If they sound good to you, don't spend too much time on the numbers.

 

[rmcohen]

Thanks for the clarification from everyone.

 

[bumpyride]

I find myself a little confused with the new HD audio formats. I know the highest for both DTS and dolby trueHD are lossless encoding schemes and the lower end ones are lossy, but do all of these schemes use 24-bit 96 kHz as their input and output. It seems to me like they would to be called HD, but I'm not sure. Anyone have any idea?

 

[mtrycrafts]

I find myself a little confused with the new HD audio formats. I know the highest for both DTS and dolby trueHD are lossless encoding schemes and the lower end ones are lossy, but do all of these schemes use 24-bit 96 kHz as their input and output. It seems to me like they would to be called HD, but I'm not sure. Anyone have any idea?

I am pretty sure DD and DTS, standard on DVD movies, is not encoded with that 24/96. But, such encoding is not really necessary for good reproduction, especially the 24 bit part.
I also think it is called HD audio because it is linked with HD movies, not pure audio discs.

 

[dave1490]

if you can answer what,s the human threshold of sound you got the answer.20 to 20 it,s like sight.

 

[bumpyride]

especially the 24 bit part

Of the two, I'd say that's probably more important. The increased dynamic range from 96 dB to 144 dB probably isn't necessary but it doesn't hurt - it also lowers quantization noise. The higher sampling rate doesn't help anything on the loudspeaker end but it does when you digitize the signal. The analog audio input has to be filtered to remove anything above the Nyquist frequency in order to prevent it from aliasing into the audible band. No filter is perfect so you're left with a region just below the Nyquist frequency where you have a mix of the rolloff from the antialias filter that happens before sampling and aliased data from components above Nyquist that weren't sufficiently rolled off by the antialiasing filter. I'd rather have all of this happening at 48 kHz instead of 22 kHz.

Personally, though, I can't really hear anything above around 17 kHz so I can't pretend this is going to matter much. But in the information age of megabit streams of high definition video, 8 streams of 24/96 audio is pretty insignificant and it would make me feel better about getting the most from my expensive home theater system.

Also, I looked at their websites and both dolby trueHD and DTS-HD are capable of up to 24-bit 96k for 7.1 channels.