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BGLeduc
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iTunes 10, AE Streaming, and Volume Control Change

Since JA has written expensively about using iTunes and Apple Express for music streaming, I thought it might be useful to point out an apparent change in iTunes 10 that affects streaming.

iTunes 9.x when used for streaming, previously had an option under Preferences/Devices to "Disable Volume control when using remote speakers", which, when checked, allowed a full range signal to be sent to the AE. This was true whether using the AE's digital or analog out (I use digital).

The option has now changed to "Allow iTunes control from remote speakers", but it does not seem to work the way the previous option worked. In fact, I am not sure HOW it works, as toggling it on and off did not seem to change the system behavior. The "Help", as of this morning, still referred to the old option.

The new behavior causes the iTunes volume control to effect the output from the AE at all times.

I use the Remote App to stream from iTunes to an AE, and find that the volume control accessible via the iPod Touch's Remote App now raises and lowers the volume from AE, even when using the digital out. The good news is that when the volume control is at maximum, it appears that the AE outputs a full range signal, the same as when the previous option for "Disable..." was checked.

But I can not prove this as I have no means to assess whether the output is still bit accurate to the source as it was in the past, per JA's reports on the subject. I did do an A/B between a stream, and the same CD played from a CD Deck, both feeding my DAC, and the levels appear to be the same.

That said, I would much prefer to have the old option back.

Brian

BGLeduc
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iTunes 10 on Mac's....Disc Mounting Failure

http://discussions.apple.com/thread.jspa?threadID=2565869&tstart=0

Looks like the issue is related to Automatic Retrieval of Track Names. Not that I would go through the hassle of entering track names manually! I will wait until it is fixed for any additional rips.

BGLeduc
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Re: iTunes 10 on Mac's....Disc Mounting Failure

Looks like it may be fixed.

A lot of VooDoo steps were being practiced by some posters as work arounds, but speculation is that it may have been a Gracenotes/iTunes issue that is now resolved.

I am importing a CD right now without problem. Fingers crossed.

Brian

deckeda
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Re: iTunes 10, AE Streaming, and Volume Control Change

I think you're referring to earlier mentions of iTunes up/down/sideways (heh) -sampling whenever its EQ, volume normalization or volume control are invoked.

So if you just leave the volume control all the way up you're still OK.

Regarding "Allow iTunes control from remote speakers"

landlsoft
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Re: iTunes 10, AE Streaming, and Volume Control Change

I'm a little confused on how the whole volume control thing works. I've got all my bits on a MacBook, feeding my CAL Alpha DAC via the fiber optic out.

I was surprised that I could control the volume via the iTunes Remote app on my iPhone. How does iTunes on my MacBook know how to alter the bits so the volume goes down ??

Thanks.

deckeda
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The Remote app tells iTunes

The Remote app tells iTunes to play another song ... the Remote app tells iTunes to adjust its own volume.

Same concept; Remote can tell iTunes to do certain things, that's all.

landlsoft
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Re: iTunes 10, AE Streaming, and Volume Control Change

Thanks, but it still doesn't make sense. Changing songs I get ... send different bits to my DAC ... but how does the volume change ??

If I had analog speakers attached to the Mac via the headphone jack and I changed the volume with the Remote App, then I'd expect the volume to change ... that I undestand, but we're talking about feeding the bits via a fiber-optic cable to a DAC. My DAC doesn't know anything about volume, it knows about bits and converting them to analog before sending that signal along to my integrated amp.

I can only turn it up as loud as my Integrated Amp's current volume setting, but I can turn it down to silenece.

Does it make the 'bits' smaller ... ha! ha! ... obviously not. I'm just tyring to understand how the bit stream changes. Does iTunes actually know how to alter the original bit-stream that represents the music or is there a secondary bit stream that provides other information such as loudness ??

I'm a Computer Dweeb who likes to understand what goes on under the covers.

Thanks for any information.

Jerryg
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Re: iTunes 10, AE Streaming, and Volume Control Change

Hi Landsoft, here is a description on how that works.

All computer hardware (including Airport Express is basically a specialized computer networking product) have basic instruction sets (firmware or microcode) built into them. Because Apple owns both products, they are able to program instructions sets (what is often referred to as a "Wrapper") with the signal that carries the music in a digital for to the DAC/Airport Express along with additional instruction sets for the Airport Express.

If Apple is writing the code properly the integrity of the music signal should be intact and the hardware should be smart enough (I shudder as my fingers type that) to strip the instruction set away from the digital Music data stream.

This allows any ITunes application or another device (if the proper instruction signal is present) to control volume among other things. Any device can have this capability as long as they have the proper firmware and electronic capabilities built into them. This isn't "Black Box", although via hardware and software patents Apple may control their specific technology as far as the devices involved here.

No they should not be compressing the music data stream. .mp3 files are already compressed (certain musical data is stripped away) when they are created. .wav files should be transmitted uncompressed and .flac are lightly compressed at file creation.

The principle is the same whether the process takes place over WIFI (Wireless) or LAN (hardwired Local Area Network cable). The difference is a different standard, software instruction set and equipment handles how the music (data) is sent to it's destination.

Networks, whatever type involve lightning fast (millisecond scale) handshakes that if an error takes place the transmission either hangs or restarts where the error takes place. The music is in a digital format until at some point in the chain a DAC takes over and produces the analog signal.

All that is involved is Ones and Zeros written in a proper format. Binary code is the proper term and it is really ugly and hard to follow. In a past life one of my duties was to fix GFE's (Group Fault Errors) in a database and it gets ugly on the instruction side of any software. Different item, but the principle is the same. My hat goes off to any binary programmers who may read this.

What was described in the beginning post was a that programmer broke the old code functionality in the new "Improved ???" code release and Apple didn't do proper "due diligence" (beta testing)before releasing the product to the general public.

That is just one of the reasons that I avoid ITunes like the plague. JRiver Media Center is far more versatile and isn't half as proprietary. You may "Pay to Play" $50 for the latest and greatest with a modest upgrade fee after the initial purchase. This includes smart device functionality built into the product.

My goal this year is to build a music server comparable to a Sooloos with touch screen for in the range of between $500 to $1500. I already have the same functionality without the touch screen in my present configuration. My budget decision is base on how and what hardware I will be replacing. Going from Vista to Windows 7 is mandatory along with the touch screen purchase.

ITunes from what I have seen doesn't have the muscle or functionality to do what I want properly. There is a reason why Gracenote, Amazon, Road Runner, Best Buy and others have their front end software written by JRiver. Yes I am very biased.

I already have the Sooloos functionality (via 3D menus) using a mouse on Vista, but want a touch screen for my dear technology challenged wife. I love her dearly, but computers are not her niche.

I hope that this is in terms that are easily understandable.

Thanks,
Jerry

John Atkinson
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iTunes & Volume Changes
landlsoft wrote:
Changing songs I get ... send different bits to my DAC ... but how does the volume change ?? Does it make the 'bits' smaller ... ha! ha! ... obviously not.

When you ask iTunes to lower the volume with Remote, it multiples each digital word representing the music by a number less than 1. Thus when you set the volume to 50% or -6dB, that multiplier is 0.5. The smaller digital words that are sent out to your external DAC result in a lower volume when converted to analog.

We recommend you leave iTunes set to maximum volume, as reducing volume in this manner also also reduces signal resolution by the same amount you are reducing volume.

John Atkinson
Editor, Stereophile

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