Analog vs Digital Inputs for Stereo - AVS Forum
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post #1 of 22 Old 03-05-2008, 09:47 AM - Thread Starter
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Ok

got my new polkies , and they sound FANTASTIC! Big step up (to my ears) from the stock
onkyo...

New problems due to speaker efficiency ....

I listened to an Audio CD that is being played via my DVD players Optical out and then listened
to that same piece of music thru my Ipod playing a 192k MP3 connected via RCA stereo cable.

The difference is HUGE. The iPod music sucks! I did expect a difference but not this big...

Here is my question...

1.Assuming I rip the same song at 320k, will the difference be less distinct ?
2.BIG question:Is it possible for the analog input to sound really close (or the same) as the digital one ?



I'm using
stock RCA cable...
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post #2 of 22 Old 03-05-2008, 10:25 AM
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All audio gets converted to analog in the end. The only question is whether that process happens at the player or in the receiver. IF the player has better D-A conversion, then analog connections should be used. If the receiver has better conversion, then a digital connection should be used.

THe Ipod output sounds bad for two reasons.

1. 192 kpbs audio vs uncompressed
2. the analog output stage from the Ipod is terrible quality
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post #3 of 22 Old 03-05-2008, 10:33 AM
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Quote:


The difference is HUGE. The iPod music sucks! I did expect a difference but not this big.

Before I get to your questions, a couple of points about this statement. First, if you expected a difference, that's will have a huge impact on what you perceive. Second, it's unlikely that the output levels of the two streams are identical, and that will also affect what you hear.

I'm not saying there's no difference at all between the two, but it's quite possible that the real difference is far less severe than what you've perceived. To check this, you'd have to carefully match the output levels of the two devices, and then compare them without knowing which was which.

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1.Assuming I rip the same song at 320k, will the difference be less distinct ?

Maybe, maybe not. If there are audible codec artifacts in the 192kbps file, they won't be in the 320kbps file. If the difference is a matter of output levels, the iPod is still going to sound just as different.

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2.BIG question:Is it possible for the analog input to sound really close (or the same) as the digital one ?

Absolutely. The DACs in iPods are quite good (per Stereophile's measurements). If you were to put an uncompressed or lossless file on your iPod, and carefully matched output levels between the iPod and the DVD player, I think you'd be very hard-pressed to tell the difference.

The question you haven't explicitly asked is, Is it possible that 192kbps would be good enough to equal the CD? The general experience of people who've tested this is, probably, most of the time. But some types of sounds are tough to compress, and if you know what to listen for you can hear differences.

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I'm using stock RCA cable.

Ain't nuthin' better.

If you can't explain how it works, you can't say it doesn't.—The High-End Creed

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post #4 of 22 Old 03-05-2008, 10:57 AM - Thread Starter
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Thanks
As far as output levels
My ipod has EQ disabled and volume set to full. I tried Pop EQ, not much better.

DVD player output levels are the same...

The difference is sound was not just the loudness. it was the depth of the midrange, the surrounding feeling etc. ipod was good for what it was but once i listened to the digital version it was lacking....

so how do i check/change output levels on the ipod ?

also my dvd player is the oppo which is reputed for quality audio circuitary
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post #5 of 22 Old 03-05-2008, 11:17 AM
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The difference between using an analog or a digital connection between a source and a receiver is simply determining where the analog conversion takes place. With analog it takes place in the source component and with digital it takes place in the receiver.

Most of the difference you heard was probably due to mismatched volume levels. The rest of it was a comparison of uncompressed against compressed music files, I would image. It doesn't likely have anything to do with the DAC's themselves. It would be fair to assume that the DAC's in both source units and receiver are perfectly competent.
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post #6 of 22 Old 03-05-2008, 11:19 AM
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Quote:
Originally Posted by matchan View Post


so how do i check/change output levels on the ipod ?

You don't. You put a voltmeter across the speaker terminals and play a test tone or white noise to set the level with the receiver's volume control.
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post #7 of 22 Old 03-05-2008, 11:25 AM
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The difference is sound was not just the loudness.

You don't know this. They could sound like they're at the same volume, but be just enough different to make one seem better than the other. That really happens.

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so how do i check/change output levels on the ipod ?

You'd need to measure the voltage at the speaker terminals, and adjust one or the other source to compensate for any difference. Depending on your set-up, this probably won't be easy to do, esp. if your iPod's already cranked all the way up. Sorry about that.

Things you could try:
1) Compare them again, without knowing which is which. (You'll need a helper to do the switching.)
2) Tweak the volume knob on your preamp/amp when you listen to the iPod, and see if it sounds closer to the CD.
3) Try a higher bitrate, and see if that improves things.

Also, what's your ultimate goal here? If you've got the CD and a good player, you don't need to use your iPod for that. And for casual earbud listening, the iPod is surely good enough. So what are you after? Knowing that could make it easier to offer advice.

If you can't explain how it works, you can't say it doesn't.—The High-End Creed

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post #8 of 22 Old 03-05-2008, 11:43 AM
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is your receiver converting the analog signal from the ipod back to digital to do some management before amplification? If so, that could be part of the problem. one digital to analog conversion vs digital to analog back to digital back to analog
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post #9 of 22 Old 03-05-2008, 11:53 AM - Thread Starter
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My goal is to get rid of physical media and store all my music in a networked server. I want to ocassionaly listen to the ipod also. I want nothing but the BEST quality of audio. I dont envision playing too many CD's....
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post #10 of 22 Old 03-05-2008, 11:54 AM - Thread Starter
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also my rca cables are 3 dollar cables from radioshack. would a top quality cable (monster?) help?
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post #11 of 22 Old 03-05-2008, 11:55 AM - Thread Starter
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Quote:
Originally Posted by mcnarus View Post

Things you could try:
1) Compare them again, without knowing which is which. (You'll need a helper to do the switching.)


The difference is huge. Its not my perception. Its like magic, instantly vibrant sound compared to mediocre sound (could not see such a big diff with the onkyo speakers)
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post #12 of 22 Old 03-05-2008, 12:14 PM
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Quote:


My goal is to get rid of physical media and store all my music in a networked server. I want to ocassionaly listen to the ipod also. I want nothing but the BEST quality of audio. I dont envision playing too many CD's.

Well, for your server get enough storage to use a lossless encoder, and you won't have to worry. For the iPod, you'll have to do some experimenting to figure out what (if anything) is the problem.

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also my rca cables are 3 dollar cables from radioshack. would a top quality cable (monster?) help?

No, no, no, no, a thousand times no. Monster is just Radio Shack with a massive marketing budget. And who do you think pays for the marketing, sucka?

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The difference is huge. Its not my perception. Its like magic, instantly vibrant sound compared to mediocre sound (could not see such a big diff with the onkyo speakers)

Yeah, maybe. But until you do a level-matched, blind comparison, you cannot be sure of that, no matter how obvious the difference seems to you. (Again, I'm not saying you're wrong. I'm just saying you can't be as sure as you think you are. If there's a few tenths of a dB difference in levels, the louder presentation can sound a lot richer, without sounding any louder. And since you admitted you were expecting a difference, your perceptions are even more suspect. It would be great if our ears were perfectly calibrated measurement instruments, but they're not.)

If you can't explain how it works, you can't say it doesn't.—The High-End Creed

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post #13 of 22 Old 03-05-2008, 01:26 PM - Thread Starter
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Thanks guys will get back to you with my findings..
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post #14 of 22 Old 03-05-2008, 02:36 PM
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Quote:
Originally Posted by matchan View Post

My goal is to get rid of physical media and store all my music in a networked server. I want to ocassionaly listen to the ipod also. I want nothing but the BEST quality of audio. I dont envision playing too many CD's....

BEST sound quality of music stored on a server:

Music server -> USB DAC -> pre-amp -> amp -> speakers

That's a basic setup. You may or may not not need a pre-amp in the end, your call. Also, if you are going for the BEST sound quality, you may have to consider other aspects as well, such as power conditioning, but you may want to leave that for later.

The critical aspect for you is getting the music out of the computer. To give you some ideas for how this can be done:
http://www.signalpathint.com/index.p...-Features.html
http://www.kingrex.com/t20.html
review: http://www.6moons.com/audioreviews/kingrex2/u.html
http://www.enjoythemusic.com/Magazin.../dared_mp5.htm
http://www.audio-magus.com

All those are low-cost solutions (<$1,000), but reading through the info will get you started.

Of course, if you want the BEST sound quality, you may have to spend $50,000. I don't think you really meant that, or did you? In any case, don't ever compress your music using a lossy format. If your source is already compromised, you will never get the BEST sound quality.

Have you checked into things such as SlimDevices, Olive Opus, or Sonos?

Best - MM
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post #15 of 22 Old 03-05-2008, 02:57 PM - Thread Starter
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I meant "Poor Mans Best Quality" (< 2k for audio) :-)
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post #16 of 22 Old 03-05-2008, 02:58 PM - Thread Starter
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I checked out Sonos and squeezebox Duet.. Both dont have the best of integrations with iTunes yet. the former is too expensive to put up in just my HT room. The latter is still too new
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post #17 of 22 Old 03-05-2008, 03:15 PM
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Well, the Squeezebox itself isn't new, and it's quite good, technically. (See the Stereophile measurements.) Don't know about iTunes integration, but I'm sure there are folks here who do.

If you can't explain how it works, you can't say it doesn't.—The High-End Creed

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post #18 of 22 Old 03-05-2008, 06:00 PM
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Quote:
Originally Posted by matchan View Post

I checked out Sonos and squeezebox Duet.. Both dont have the best of integrations with iTunes yet. the former is too expensive to put up in just my HT room. The latter is still too new

iTunes integration with the Squeezebox is indeed somewhat lacking. The Sonos system would fall very nicely into your budget. All you would need is a ZP80 unit and a remote, which is great.

However, if you don't need a wireless solution, the simplest would be to get a dedicated DAC, which should cost you at most $400, depending on the device.

Regarding the iPod, it is generally recommended to turn off the equalizer and to set the output to maximum to make full use of the entire dynamic range. You should follow the same rules when you play music from your server. Let the receiver do all the processing.

Regarding quality of 192 kbps vs. 320 kbps vs. lossless, you should be able to find that out for yourself.

Best - MM
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post #19 of 22 Old 03-08-2008, 05:28 AM
 
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I can't believe nobody has mentioned this yet.....but your biggest problem is that you're using the iPod's headphone jack.

It doesn't matter whether you're using 192 or 256 or 320 or even lossless or a WAV file, it's all going to sound like crap if you're outputting through the headphone jack.

To do it right, you need a dock or the AV cables. You want to connect through the charger/interface port, not the headphone jack.
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post #20 of 22 Old 03-08-2008, 06:09 AM
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I received my Duet yesterday, and my iTunes is working GREAT. I had already spent a few days ripping all my Cds in Apple Lossless format to iTunes because I love the software so much. In the back of my mind I was worried that maybe things wouldn't work smoothly with the Squeezebox, but all my fears were completely dissolved last night. I had the single best music listening experience ever from around 2am to 5am this morning. I was in my listening room, completely dark except for the glow of tubes in my preamp and the LCD display of the Duet controller. It played every single iTunes track to perfection. It recognized every song in my iTunes library and allowed me to navigate through my entire track list at the push of a button. It was awesome...it's SO nice to be rid of my CD player!

As for the iPod, I have a cable that avoids the little piece of crap headphone amp and runs the signal straight from the DAC of the iPod into my preamp. I've actually been quite pleased with the sound of my iPod nano, though I never intended it to be my main source. I'll add an outboard DAC to my Duet at some point, but as of right now I have no pressing need to do that. It's the best four hundred bucks I've spent in a while, and the customer service is excellent.
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post #21 of 22 Old 03-08-2008, 06:10 AM
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Quote:
Originally Posted by big angry View Post

I can't believe nobody has mentioned this yet.....but your biggest problem is that you're using the iPod's headphone jack.

It doesn't matter whether you're using 192 or 256 or 320 or even lossless or a WAV file, it's all going to sound like crap if you're outputting through the headphone jack.

To do it right, you need a dock or the AV cables. You want to connect through the charger/interface port, not the headphone jack.

Bingo.
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post #22 of 22 Old 03-08-2008, 02:40 PM
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Quote:
Originally Posted by big angry View Post

I can't believe nobody has mentioned this yet.....but your biggest problem is that you're using the iPod's headphone jack.

It doesn't matter whether you're using 192 or 256 or 320 or even lossless or a WAV file, it's all going to sound like crap if you're outputting through the headphone jack.

To do it right, you need a dock or the AV cables. You want to connect through the charger/interface port, not the headphone jack.

Actually I did in the 2nd post but I was not clear enough about it...thanks for the clarification and it is indeed the problem here. The headphone output is TERRIBLE audio quality.
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