Innovation or e-waste? Apple rumored to ditch headphone jack

[Greg Anos]

Originally Posted by Katsunami

Everything from Classical to Nightwish and Deep Purple, and from Dire Straits to Enya and Secret Garden.

Throw in Satchmo, Rat Pack, and other Jazz from the '50s and '60s. And Morricone...

[kennyc]

Originally Posted by tubemonkey

Without a headphone jack, Apple can make iPhones as thick as a human hair

Not only that, they've registered the name iToo and they've contracted with a gang of mutant bikers to tattoo them on millennials all over the country.

[jbjb]

Originally Posted by Katsunami

Because the number of bits determines how loud music can become.

Not really. The number of bits determines the maximum dynamic range that can be captured (or, another way of looking at it, the maximum signal-to-noise ratio that can be achieved). Every extra bit adds another (roughly) 6dB of dynamic range. This doesn't have to equate to louder music.

If the full 24 bits of dynamic range would be used, a 24-bit song would blow your head to kingdom come.

Not necessarily. More usefully, the extra bits can give you better resolution without changing the full scale deflection of the output waveform. The same maximum signal amplitude can be split into more steps, reducing quantisation noise, and improving dynamic range.

Remember, dBs define a (logarithmic) ratio between 2 quantities (in the case of dynamic range the ratio between the largest and smallest amplitude signals that can be represented), not an absolute value.

The maximum recordable frequency is the half of the sample rate. A CD has a 44.1 kHz sample rate, so it can record up to +/- 22 kHz.

You can only actually achieve the theoretical maximum if you have a perfect anti-aliasing filter when sampling the signal. Hence the common use of oversampling to allow the sharp 20-odd kHz cutoff to be done digitally.

Having said all that, I certainly agree that 16 bits @ 44.1 kHz sampling rate is plenty for a delivery format - as you say the real benefit of 24bit/192KHz is to prevent accumulation of errors through the editing process.

/JB

[Katsunami]

Originally Posted by jbjb

Not really. The number of bits determines the maximum dynamic range that can be captured (or, another way of looking at it, the maximum signal-to-noise ratio that can be achieved). Every extra bit adds another (roughly) 6dB of dynamic range. This doesn't have to equate to louder music.

True. A 16-bit CD has a dynamic range of 96 dB; because 16 x 6 dB = 96 dB.

Not necessarily. More usefully, the extra bits can give you better resolution without changing the full scale deflection of the output waveform. The same maximum signal amplitude can be split into more steps, reducing quantisation noise, and improving dynamic range.

Remember, dBs define a (logarithmic) ratio between 2 quantities (in the case of dynamic range the ratio between the largest and smallest amplitude signals that can be represented), not an absolute value.

I'm not knowledgeable enough to discuss this subject on a highly technical level. I do think, however, that 24 bits x 6 dB = 144 dB is enough to render you deaf if the dynamic range of 24 bit would be fully used to create the loudest music possible.

You can only actually achieve the theoretical maximum if you have a perfect anti-aliasing filter when sampling the signal. Hence the common use of oversampling to allow the sharp 20-odd kHz cutoff to be done digitally.

You lost me there. I'll have to look into that.

Having said all that, I certainly agree that 16 bits @ 44.1 kHz sampling rate is plenty for a delivery format - as you say the real benefit of 24bit/192KHz is to prevent accumulation of errors through the editing process.

Same as with RAW pictures from a camera

[jbjb]

Originally Posted by Katsunami

True. A 16-bit CD has a dynamic range of 96 dB; because 16 x 6 dB = 96 dB.

Correct. (At least in theory - in practice, theoretical maxima are rarely achieved )

I'm not knowledgeable enough to discuss this subject on a highly technical level. I do think, however, that 24 bits x 6 dB = 144 dB is enough to render you deaf if the dynamic range of 24 bit would be fully used to create the loudest music possible.

The point is that, because the dynamic range in question is the *ratio* between the loudest and quietest sounds available, the enhanced dynamic range doesn't have to be used to make the loudest sound louder, you can instead use it to allow you to lower the threshold where quiet sounds disappear into the quantisation noise floor. (And, more generally, reduce the level of quantisation noise throughout).

dBs of dynamic range are not to be confused with sound pressure dBs - they're both ratios, but ratios of different things. Just because a source has 144dB of DR, it doesn't mean you have to play it at 144 dB of sound pressure level (which would indeed damage your ears)!

Same as with RAW pictures from a camera

Exactly !

/JB

[jbjb]

Originally Posted by Katsunami

You lost me there. I'll have to look into that.

The anti-aliasing filter comment was just an aside - it doesn't really affect the discussion in any way. In practice you can get close enough to the theoretical 22.05 kHz to exceed normal human hearing, so your point stands. The aim was to be able to capture 20kHz, and the 44.1kHz sample rate gives a bit of a window for the anti-aliiasing filter roll-off.

/JB

[ApK]

Originally Posted by MikeB1972

Any idea why they are trying to make CD's louder? Every device I have listened to a CD on, has either a magic spinny knob thing or buttons that make the volume go up or down.

Because to the average music consumer listening on average consumer gear, louder is perceived as 'better.' That was the reason, IIRC.
And the increased dynamic range compression, needed to fit the louder music into CD format, was not usually a problem for this group because we want to hear the soft passages as distinctly as the loud passages, while running on the treadmill, over the ambient noise, without riding the volume control, so, hey, even better.

[Katsunami]

Originally Posted by jbjb

The point is that, because the dynamic range in question is the *ratio* between the loudest and quietest sounds available, the enhanced dynamic range doesn't have to be used to make the loudest sound louder, you can instead use it to allow you to lower the threshold where quiet sounds disappear into the quantisation noise floor. (And, more generally, reduce the level of quantisation noise throughout).

Oh, is this something akin to using resolution to create a sharper image, instead of creating more space on a computer screen?

Let's say you have a 1600x1200 (4:3) monitor at 24 inch. You could use a 3200x2400 monitor to create 4x the working space (and squint yourself to hell, probably), or you could do a 200% scale, and create a working space that is effectively the same as 1600x1200, but much sharper.

[Katsunami]

Originally Posted by ApK

Because to the average music consumer listening on average consumer gear, louder is perceived as 'better.' That was the reason, IIRC.

There's another reason, and that started in the 60's already, with vinyl.

A jukebox contained many singles. The jukebox would play on a set volume, and artists/producers wanted their specific single to stand out. To achieve this, the vinyl was, as it's called, 'cut hotter'. Don't ask me what this process entails; I have no knowledge of analog music production.

With CD's, this was not possible: a CD was mastered, and it was done. At the time, there was no way to edit digital music to 'cut a hot CD', but as digital processing evolved, this became possible.

A CD can be made A LOT louder than vinyl before distortion sets in.

I have some music that I only have for completionists sake; to keep everything from that artist complete. A CD that would play at 95-100 dB on a reference system with a dynamic range of 5 is no fun to listen to. There are no dynamics left, and setting the CD to a lower volume doesn't fix that.

Dynamic range that is lost can't be gotten back; compare it with blown out whites or blocked up parts in a picture. (OK, a RAW-file can help somewhat, but the results will never become optimal again.)

[jbjb]

Originally Posted by Katsunami

Oh, is this something akin to using resolution to create a sharper image, instead of creating more space on a computer screen?

Let's say you have a 1600x1200 (4:3) monitor at 24 inch. You could use a 3200x2400 monitor to create 4x the working space (and squint yourself to hell, probably), or you could do a 200% scale, and create a working space that is effectively the same as 1600x1200, but much sharper.

Exactly.

With 16-bit sampling of an analogue signal, the input maximum amplitude range is divided into 65536 (2 to the 16th power) levels, and the value of the input signal at each sample point is approximated by the nearest level. With 24-bit sampling, you're dividing the input range into 16777216 (2 to the 24th power) steps, which clearly gives a much more accurate representation of the sampled signal.

This process is known as quantisation, and the differences between the 'real' analogue input values and their quantised approximations ('quantisation error') effectively adds some noise, which is known as 'quantisation noise'. If we have smaller steps, we have, on average, less quantisation error per sample, and hence less quantisation noise.

/JB

[Shane R]

This thread has taken an interesting twist.

[Conan46]

Here is a site to check an album's dynamic range:
http://dr.loudness-war.info/
As someone who has listened to Rush and am a fan, beginning with them on Vinyl all the way back to their Fly By Night album. I definitely notice the noise and mess of a song like this one:
https://www.youtube.com/watch?v=wLNfkVsW1Ck
here is the dynamic range chart of the song
http://dr.loudness-war.info/album/li...m=vapor+trails

[Conan46]

Originally Posted by Shane R

This thread has taken an interesting twist.

True It shows that simply changing a plug can have broader implications

[jhowell]

And to go even further down the digression rabbit hole...

The bel (named for Alexander Graham Bell) is a base-10 logarithmic unit for measuring ratios. The decibel (dB, tenth of a bel) is a convenient unit of measurement since 1 dB is approximately the just noticeable difference (JND) in sound intensity for a normal person. Changes in sound intensity of less than 1 dB are imperceptible.

When discussing dB in audio you need to take into account whether you are referring to voltage or power (sound intensity). A CD uses 16-bit samples, which indicate the voltage of the signal. Adding a bit doubles the number of possible voltage levels. This is a log10(2)=0.3 bel (3 dB) increase. However, power increases with the square of voltage (for a fixed load resistance) which means that dB of sound intensity are double dB of voltage, or 6 dB per bit.

[Katsunami]

Originally Posted by jbjb

Exactly.

With 16-bit sampling of an analogue signal, the input maximum amplitude range is divided into 65536 (2 to the 16th power) levels, and the value of the input signal at each sample point is approximated by the nearest level. With 24-bit sampling, you're dividing the input range into 16777216 (2 to the 24th power) steps, which clearly gives a much more accurate representation of the sampled signal.

This process is known as quantisation, and the differences between the 'real' analogue input values and their quantised approximations ('quantisation error') effectively adds some noise, which is known as 'quantisation noise'. If we have smaller steps, we have, on average, less quantisation error per sample, and hence less quantisation noise.

/JB

OK, I understand now; I know about that topic (the basics, at least). While you're right, the same dude as I quoted before essentially says: "It doesn't matter. Quantisation noise is so low with 16 bit already that stepping up to 24 bit is useless." (For listening, not editing.)

He says so in the video on this page:

https://xiph.org/video/vid2.shtml

"It *might* have been more important if the CD had been 14 bit, as originally planned.... maybe."