# HD audio?



## spamreef (Dec 1, 2010)

what the ? is HD audio? Is there a such thing? I do notice when i switch to a HD show on my dishnetwork that the volume seems lower,,,does this have anything to do with HD audio?


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## RBTO (Jan 27, 2010)

I believe you're confusing two uses of the term HD. The term "HD", by itself, is generally applied to video. Satellite and BluRay are the most common sources of HD video, although there are now numerous streaming HD video sources popping up. These are usually accompanied with high quality audio tracks but those are not necessarily referred to as _HD audio_.

The term, "HD Audio", is generally applied to audio transmitted by AM and FM stations using a newer digital technique which allows much higher audio quality relative to their conventional non-digital format. HD AM audio is likened to FM quality, and HD FM audio is likened to CD quality. The transmission method also allows additional information such as song title and artist, etc., etc., to be included. Special HD receivers are required to make use of the HD signal, most of which are showing up in automotive applications, although home HD receivers are available (these receivers have no video capabilities - they are essentially radio receivers).

The volume differences you noted in switching between HD and non-HD _video_, are due to the way sound is encoded for each, and doesn't relate to "HD audio" at all. That being said, the audio encoded for HD video is usually much superior to that for non-HD video, but that's because of the HD _video_ format which is used to carry it.


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## Kal Rubinson (Aug 3, 2006)

RBTO said:


> I believe you're confusing two uses of the term HD. The term "HD", by itself, is generally applied to video. Satellite and BluRay are the most common sources of HD video, although there are now numerous streaming HD video sources popping up. These are usually accompanied with high quality audio tracks but those are not necessarily referred to as _HD audio_.


They are not referred to as _HD audio_ from cable and streaming sources because they are not. However, Blu-ray discs usually do have a true HD audio tracks, designated as LPCM, Dolby TrueHD or dtsHD MA.



> The term, "HD Audio", is generally applied to audio transmitted by AM and FM stations using a newer digital technique which allows much higher audio quality relative to their conventional non-digital format. HD AM audio is likened to FM quality, and HD FM audio is likened to CD quality. The transmission method also allows additional information such as song title and artist, etc., etc., to be included. Special HD receivers are required to make use of the HD signal, most of which are showing up in automotive applications, although home HD receivers are available (these receivers have no video capabilities - they are essentially radio receivers).


Yes, quality is good and the bells&whistles are appreciated but to say it is HD is to mislead as HD is generally regarded as audio superior to CD.


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## RBTO (Jan 27, 2010)

Kal Rubinson said:


> They are not referred to as _HD audio_ from cable and streaming sources because they are not. However, Blu-ray discs usually do have a true HD audio tracks, designated as LPCM, Dolby TrueHD or dtsHD MA.


I think you're referring to the _*other*_ definition of HD audio - audio that is sampled at higher frequencies (e.g., 192kHz) and with more bits (e.g., 32 bits) than typical. Yes, many BluRay disks have HD audio by this definition.



Kal Rubinson said:


> Yes, quality is good and the bells&whistles are appreciated but to say it is HD is to mislead as HD is generally regarded as audio superior to CD.


I'm not saying AM HD is superior audio (nor FM HD either). I just described the two in a manner usually used by industry. When it comes down to the actual result, that's another story. Go here for a better explaination:

http://en.wikipedia.org/wiki/HD_Radio 

I really don't want to get all tangled up in semantics here, but "HD Audio" can refer to several different things.

1) Audio transmitted using a digital signal and conventional AM or FM transmission (see above link): hence, HD radio receivers (more correctly referred to as "HD Radio").
2) A loose term for the audio that comes along with High Definition video (though it doesn't imply the audio is high fidelity). This is somewhat like saying "television audio" or "radio audio". Read: any audio that is provided with a HD (video) source.
3) Digital audio encoded with the Intel standard specifying higher bit rates, more bits, and more channels of audio, which is not necessarily the audio supplied on a BluRay disk. (See: http://en.wikipedia.org/wiki/Intel_High_Definition_Audio)
4) And, I guess the term "HD Audio" that _DOES_ imply superior high fidelity audio, with a superior technology behind it.

The key here, is to know which use of the term is being used. "HD audio" may or may not mean _high quality_ audio.

I just hope this answered spamreef's original question sufficiently.


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## Kal Rubinson (Aug 3, 2006)

> I'm not saying AM HD is superior audio (nor FM HD either). I just described the two in a manner usually used by industry. When it comes down to the actual result, that's another story. Go here for a better explaination:
> 
> http://en.wikipedia.org/wiki/HD_Radio
> 
> ...


No argument with you about the multiple meanings but (4) is the literal meaning and the rest are either shaded or imposed by marketers.



RBTO said:


> I think you're referring to the _*other*_ definition of HD audio - audio that is sampled at higher frequencies (e.g., 192kHz) and with more bits (e.g., 32 bits) than typical. Yes, many BluRay disks have HD audio by this definition.


Yes, the literal meaning of *h*igh *d*efinition audio.


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## Sir Terrence (Jun 8, 2006)

RBTO said:


> I think you're referring to the _*other*_ definition of HD audio - audio that is sampled at higher frequencies (e.g., 192kHz) and with more bits (e.g., 32 bits) than typical. Yes, many BluRay disks have HD audio by this definition.


I think the more appropriate term would be High Resolution Audio, not high definition audio. Definition is more appropriate to what we see, and resolution is more appropriate to what we hear. 





> I'm not saying AM HD is superior audio (nor FM HD either). I just described the two in a manner usually used by industry. When it comes down to the actual result, that's another story. Go here for a better explaination:
> 
> http://en.wikipedia.org/wiki/HD_Radio
> 
> ...


Number one should be defined as digital radio, not HD radio. Digital radio does not offer any more resolution than analog radio. The only difference between the two is one is digitized, the other is not. HD radio is marketing speak, as technically there is nothing really HD about digital radio. 

Number two would be high definition video with digital audio. If the audio does not exceed the Redbook standard of 16/44.1khz, or 16/48khz(for DVD), it cannot be considered as high resolution. These two bit and sample rates are a minima for coding quality digital signals. 

Number three is a red herring, as no 32bit signal would be preserved passing through the innards of a computer. Too much noise, and too much interference would prevent it. However this is closer to what you will hear on Bluray disc in the form of High Resolution 24/192khz audio. 32bit is more beneficial to the recording side than the consumer side. Any mention of 32 bits on the consumer side is nothing more than marketing terminology. Technically, there is nothing out there on the consumer side that performs truly at 32 bit resolution. 

Number four would be better termed as High Resolution Music. 

The term HD audio was created by Intel. Since Intel has zero to do with recording and distributing music, their terminology should be taken with a grain of salt. High Resolution music is a distinction made with within the audio community, and that should be given more credence than something coming out of the computer industry. That is just my opinion though, you can take it with a grain of salt as well.


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## Kal Rubinson (Aug 3, 2006)

Sir Terrence said:


> I think the more appropriate term would be High Resolution Audio, not high definition audio. Definition is more appropriate to what we see, and resolution is more appropriate to what we hear.


Why make that distinction? They both refer to the precision of the representation of some aspect reality and apply equally well to mechanical energy (sound) and electromagnetic energy (picture). 



> Number four would be better termed as High Resolution Music.


I prefer high definition sound since not everyone concurs on the exact distinction between music and noise.:bigsmile:


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## Sir Terrence (Jun 8, 2006)

Kal Rubinson said:


> Why make that distinction? They both refer to the precision of the representation of some aspect reality and apply equally well to mechanical energy (sound) and electromagnetic energy (picture).


You are correct. But since when have marketing people paid any distinction to how anything is applied based on precision? HD radio for instance really means Hybrid digital radio. However the use of HD(as everyone else knows it) means to most folks as "high definition" radio, of which the two definitions have really nothing in common. You cannot make that mistake when using "high resolution" audio, because there is an established threshold between digital standard audio(CD quality), and truly high resolution digital audio(which implicates bit and sample rates above red book standard). You are correct that both can be used interchangeably, but will the public be able to clearly understand what is what using them interchangeably? 

Semantics shemantics, that's all it is in the end. But there has to be a reason that HDTV was used, and not HRTV. My guess would be association. When you look up high definintion on google, you get a wide variety of video related information, not much in the way of audio. If you look up High definition audio, you get information on Intel high definition audio standard as it relates to computers, but that is about it in the way of music. When you google high resolution audio, you get nothing but audio related topics, and no video related stuff. I guess that is my logic for the distinction. 




> I prefer high definition sound since not everyone concurs on the exact distinction between music and noise.:bigsmile:


Subjectivity would never make a clear distinction between high resolution and high definition. One mans noise is another mans music. Another mans music, is another's noise. :dontknow:


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## FlashJim (May 6, 2006)

Sir Terrence said:


> Subjectivity would never make a clear distinction between high resolution and high definition. One mans noise is another mans music. Another mans music, is another's noise. :dontknow:


Absolutely. I suffered through the whole "Industrial" thing. I say suffered because I liked quite a few of the bands, but hated it when the songs were complete distortion and screaming. Luckily some of those very bands mellowed and matured into something great. Trent Reznor comes to mind. I adore the Beside You in Time HD-DVD. Razor sharp video and fantastic audio.

Getting back to the "HD Audio" thing ... is there a FAQ or "must have" list somewhere for DVD-Audio? I'm interested in trying them out. Steely Dan's Gaucho is at the top of my list.


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## Kal Rubinson (Aug 3, 2006)

Sir Terrence said:


> You are correct. But since when have marketing people paid any distinction to how anything is applied based on precision? HD radio for instance really means Hybrid digital radio. However the use of HD(as everyone else knows it) means to most folks as "high definition" radio, of which the two definitions have really nothing in common. You cannot make that mistake when using "high resolution" audio, because there is an established threshold between digital standard audio(CD quality), and truly high resolution digital audio(which implicates bit and sample rates above red book standard). You are correct that both can be used interchangeably, but will the public be able to clearly understand what is what using them interchangeably?
> 
> Semantics shemantics, that's all it is in the end. But there has to be a reason that HDTV was used, and not HRTV. My guess would be association. When you look up high definintion on google, you get a wide variety of video related information, not much in the way of audio. If you look up High definition audio, you get information on Intel high definition audio standard as it relates to computers, but that is about it in the way of music. When you google high resolution audio, you get nothing but audio related topics, and no video related stuff. I guess that is my logic for the distinction.


Yup. That is the power of marketing and the reason that the developers of IBOC broadcasting chose to market it as HD Radio while denying, officially, that it is intended to mean High Definition.


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## Kal Rubinson (Aug 3, 2006)

FlashJim said:


> Getting back to the "HD Audio" thing ... is there a FAQ or "must have" list somewhere for DVD-Audio? I'm interested in trying them out.


DVD-Audio is dead in the water. You need a DVD player with this particular capability and that includes most of the modern BD-Universal players.


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## nova (Apr 30, 2006)

HD does not seem to mean much of anything anymore, unless you're in marketing. I mean, High Def paint from Valspar and Lowes... serious??? I suppose it fits somewhere in between HD video and HD audio, no? :coocoo:


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## vann_d (Apr 7, 2009)

The volume on non-HD channels is louder because of the compressed dynamic range. That is, the difference between loud sounds and soft sounds has less range than that of HD-video program. Everything is more averaged toward the middle and then I think it is all boosted a few dB to make it louder.

Commercials sound even louder because their dynamic range is even more compressed and then they raise the average sound level even more to make sure you can hear it.

Very annoying...


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## vann_d (Apr 7, 2009)

nova said:


> HD does not seem to mean much of anything anymore, unless you're in marketing. I mean, High Def paint from Valspar and Lowes... serious??? I suppose it fits somewhere in between HD video and HD audio, no? :coocoo:


Yes, you're exactly right. It's like "titanium". For a while, everything that came out was "titanium" something. funny


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## WooferHound (Dec 8, 2010)

Everything is High Definition now, I see commercials on TV and in magazines for many things these days.
HD Windows
HD Sunglasses
HD Paint
HD Lighting
and many more things that I can't remember now. It's gotten so that it all just blows over my head when they say High Definition in advertising because it really doesn't mean anything real anymore.


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## spamreef (Dec 1, 2010)

ok I think I get it now lol so the so called HD audio is better as far as dynamic range but the HD part is a misnomer......?


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