Volume: How much and how do you control it?

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neekomax

Re: Volume: How much and how do you control it?
« Reply #20 on: 15 Aug 2011, 01:14 pm »
According to who?

The players are a lot more sophisticated than they used to be.

Well, I got waved off of that technique big time by others who told me that digital volume attenuation removes digital information, so, say, if you have 16 bits at full volume, you have 15 bits if you turn it down a bit, etc. So I stopped using it.

JohnR

Re: Volume: How much and how do you control it?
« Reply #21 on: 15 Aug 2011, 01:16 pm »
Well, I got waved off of that technique big time by others who told me that digital volume attenuation removes digital information, so, say, if you have 16 bits at full volume, you have 15 bits if you turn it down a bit, etc. So I stopped using it.

You stopped using because "others" said so, not because you heard a difference? :nono:



JohnR

Re: Volume: How much and how do you control it?
« Reply #22 on: 15 Aug 2011, 01:32 pm »
Ha ha, I had to add a :nono: smiley to that.

Seriously, the statement given is only true in the worst possible case. Most of the players now (maybe not iTunes, but the ones I looked at recently) use a lot of bits for internal arithmetic, and "dither" to spread the noise spectrum out. In my opinion it's all very exciting.

neekomax

Re: Volume: How much and how do you control it?
« Reply #23 on: 15 Aug 2011, 01:33 pm »
I actually did/do hear a difference. Just didn't understand the reason for it until I was informed. It's why I had asked the question in the first place.

Newer versions of players have dithered volume control, which is an attempt to compensate for this fact. But you're still losing data, so if you're cool with that...

Since I put my digital volumes at 100% and control volume with my preamp, it has made a big difference. Try putting your digital volume at 25% and see if you don't think SQ is compromised. Unless your technology is something I'm not aware of, it will be.

neekomax

Re: Volume: How much and how do you control it?
« Reply #24 on: 15 Aug 2011, 01:34 pm »
Which player are you using?

JohnR

Re: Volume: How much and how do you control it?
« Reply #25 on: 15 Aug 2011, 01:40 pm »
But you're still losing data,

Uh... no, you are not.

neekomax

Re: Volume: How much and how do you control it?
« Reply #26 on: 15 Aug 2011, 02:02 pm »
Uh... no, you are not.

Right, ok, well that clears that right up :?

You're saying that dithering actually conserves the original data? That has not been my understanding. Care to elaborate?

JohnR

Re: Volume: How much and how do you control it?
« Reply #27 on: 15 Aug 2011, 02:12 pm »
I'm assuming that you have sufficient bit length at the output i.e. 16 in, 24 out, which I think is probably typical. (no?) Take your example of having the volume "halved" - shift right one bit. Does the data change? No, not a bit (ha - OK, one bit exactly). It's exactly the same, extra zero-padding bits and shifts aside. Fair enough, take it down more than 8 bits and you lose data - but this should be well down below other factors like noise unless you have a gain issue in your system.

In general, I think these "bit" and "data" arguments are forgetting that the digital signal is a representation of an analog signal, and that the real goal is to reproduce the analog signal as accurately as possible. So in general, I think that using the processing power on the computer for things like upsampling and dithered volume control is really moving in the right direction.

neekomax

Re: Volume: How much and how do you control it?
« Reply #28 on: 15 Aug 2011, 03:58 pm »
Perhaps that is where our cases differ; there is no upsampling going on in my setup. My 16 bit music is played back in 16bit, streamed in 16bit, and my DAC uses 16bit conversion. Therefore, as far as I know, there are no extra bits of 'padding' to be lost without sacrificing musical data.

I'm assuming that you have sufficient bit length at the output i.e. 16 in, 24 out, which I think is probably typical. (no?) Take your example of having the volume "halved" - shift right one bit. Does the data change? No, not a bit (ha - OK, one bit exactly). It's exactly the same, extra zero-padding bits and shifts aside. Fair enough, take it down more than 8 bits and you lose data - but this should be well down below other factors like noise unless you have a gain issue in your system.

In general, I think these "bit" and "data" arguments are forgetting that the digital signal is a representation of an analog signal, and that the real goal is to reproduce the analog signal as accurately as possible. So in general, I think that using the processing power on the computer for things like upsampling and dithered volume control is really moving in the right direction.

JLM

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Re: Volume: How much and how do you control it?
« Reply #29 on: 15 Aug 2011, 04:49 pm »
Thanks for the condescending reminder. "Realistic" does not mean "loud all day long" - it means "realistic."

John,

For "big time" rockers, realistic could easily exceed 85 dB average spls.

Neekomax, I was thinking of sound quality.

neekomax

Re: Volume: How much and how do you control it?
« Reply #30 on: 15 Aug 2011, 04:56 pm »
Neekomax, I was thinking of sound quality.

In general, is there a best practice for this? Amp high, pre low? Amp low, pre high? Both nearer the middle (that's how I have it), or is it completely dependant on the gear in question?

Related question (I think): What is output impedance, and how do you know what your pre's is, and what it should be relative to your amp?

Obviously I'm super ignorant  :roll:

srb

Re: Volume: How much and how do you control it?
« Reply #31 on: 15 Aug 2011, 05:07 pm »
Perhaps that is where our cases differ; there is no upsampling going on in my setup. My 16 bit music is played back in 16bit, streamed in 16bit, and my DAC uses 16bit conversion. Therefore, as far as I know, there are no extra bits of 'padding' to be lost without sacrificing musical data.

I would agree with that.  The 16-bit depth is maintained but if you are using the newer 2nd Generation Apple TV, users who have a sample rate display on their DAC report that 44.1KHz files are resampled to 48KHz, which is apparently not the case with the 1st Generation Apple TV and Airport Express.
 
As far as hearing a difference in digital volume control settings, I do hear a reduction in dynamics with either iTunes or J. River Media Center volume controls attenuated.  With Airplay, I often use the digital volume controls to adjust the volume in remote zones, but when my listening turns less casual, I crank the iTunes volume control up to 100%, or in the case of J. River, disable the volume control.
 
Steve

Steve

Re: Volume: How much and how do you control it?
« Reply #32 on: 15 Aug 2011, 06:37 pm »
Fair enough, take it down more than 8 bits and you lose data - but this should be well down below other factors like noise unless you have a gain issue in your system.


I believe AES recommends 24/192 if I remember correctly. And sometime back JJ himself stated that 20khz bandwidth will sound "smeared" (On Stereophile forum). 16/44 will have approximately 20khz analog bandwidth.

Isn't 24 bit recording and 24 bit playback rather manditory for best fidelity?

Am I missing something?

Cheers.

srb

Re: Volume: How much and how do you control it?
« Reply #33 on: 15 Aug 2011, 07:01 pm »
Isn't 24 bit recording and 24 bit playback rather manditory for best fidelity?

In theory, yes.  But the recording production itself is important (analog microphones, analog mic preamps, acoustics, mixing, etc.), and many of us have 16/44.1 recordings that sound better than a number of 24/192 recordings made from that resolution or higher masters.
 
I think 16/44.1 recordings will comprise a respectable portion of most people's music library for some time to come, for the above reasons and because of availability (or lack of).
 
Steve

Steve

Re: Volume: How much and how do you control it?
« Reply #34 on: 15 Aug 2011, 09:09 pm »

In theory, yes.  But the recording production itself is important (analog microphones, analog mic preamps, acoustics, mixing, etc.), and many of us have 16/44.1 recordings that sound better than a number of 24/192 recordings made from that resolution or higher masters.
 
I think 16/44.1 recordings will comprise a respectable portion of most people's music library for some time to come, for the above reasons and because of availability (or lack of).
 
Steve

Yes, I know the analog portions of the recording (mic, gainstages) are important, but shouldn't they be upgraded? The research I have performed (decade or more ago) clearly demonstrated that extending beyond 20khz in analog does make a sonic difference.

Just a couple of years ago, Jneutron mentioned some work (I believe a 1982 paper) on another forum that demonstrated we can detect 2us, and Dr. Kunchur demonstrated just a few years ago that we can detect 5us changes.

On the other side, I do have some pretty descent sounding 16/44 CDs.

Cheers.

*Scotty*

Re: Volume: How much and how do you control it?
« Reply #35 on: 15 Aug 2011, 09:51 pm »
neeko,in response to your output impedance question. It is advisable to have a ten to one ratio between source and preamp and preamp and power amp. By way of explanation if the preamp input is 10Kohms the source component should be 1Kohm or lower. For the sake of dynamics the source should actually be an order of magnitude lower,around 100 ohms or less. If the power amp input impedance is 27Kohms the preamp output should be less than 2.7Kohms for the same reasons mentioned above the actual output impedance should be lower much much lower.
 This ten to one ratio minimizes the possibility of high frequency roll-off due to interconnect cable
capacitance in combining with the preamp and power amps impedances to create a filter pole inside the audio bandwidth.
 A filter pole is always created when two components are connected together by a cable with capacitance,the trick is to have the 3dB down point well outside the audio band,ten times higher isn't a bad figure to shoot for.
Scotty

neekomax

Re: Volume: How much and how do you control it?
« Reply #36 on: 15 Aug 2011, 09:59 pm »
neeko,in response to your output impedance question. It is advisable to have a ten to one ratio between source and preamp and preamp and power amp. By way of explanation if the preamp input is 10Kohms the source component should be 1Kohm or lower. For the sake of dynamics the source should actually be an order of magnitude lower,around 100 ohms or less. If the power amp input impedance is 27Kohms the preamp output should be less than 2.7Kohms for the same reasons mentioned above the actual output impedance should be lower much much lower.
 This ten to one ratio minimizes the possibility of high frequency roll-off due to interconnect cable
capacitance in combining with the preamp and power amps impedances to create a filter pole inside the audio bandwidth.
 A filter pole is always created when two components are connected together by a cable with capacitance,the trick is to have the 3dB down point well outside the audio band,ten times higher isn't a bad figure to shoot for.
Scotty

Thanks for that. Not your fault, but I don't really understand it at all.  :oops: Oh well.

I guess I could start by finding out what the various impedances of my components are, right? Is that usually listed in the specs?

*Scotty*

Re: Volume: How much and how do you control it?
« Reply #37 on: 15 Aug 2011, 10:01 pm »
Steve, I think the reason the frequency extension beyond 20kHz sounds better is that you have moved the filter pole created by the roll-off of the high frequencies further away from the audio band.
 When the filter pole is close to the audio band you hear the effects of the phase shift that comes along for the ride and these effects may extend clear down into the mid-range.
Scotty

srb

Re: Volume: How much and how do you control it?
« Reply #38 on: 15 Aug 2011, 10:05 pm »
I guess I could start by finding out what the various impedances of my components are, right? Is that usually listed in the specs?

We would all think and hope so, and sometimes they are, but all too often you will see posts asking "Does anyone know the input (or output) impedance of ........"
 
Steve

neekomax

Re: Volume: How much and how do you control it?
« Reply #39 on: 15 Aug 2011, 10:10 pm »

We would all think and hope so, and sometimes they are, but all too often you will see posts asking "Does anyone know the input (or output) impedance of ........"
 
Steve

Ha. Right.

Acurus DIA-100 amp = 10k input impedance.
Peachtree Audio Decco preamp output impedance = no idea  :roll:

If the signal from the source is digital (Apple TV via Toslink), does the impedance thing still apply?

How critical is all this anyway?