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JIMV
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A Rookie upsampling question

I have owned CD players that upsample. I have never owned a DAC that had the capability so I am going to ask a foolish question. The Benchmark DAC1 has upsampling ability. How does this work. Does it simply recognize an upsampled data stream from a CD player or source, or does it take a signal from a CD player and then do the upsampling. I ask because I hope to aquire the DAC1 and am curious about which inexpensive CD player to use with it, one that upsamples or a cheaper one that does not but that I already own???

Jan Vigne
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Re: A Rookie upsampling question

The transport reads the ones and zeroes off the disc and then passes it to the D to A portion of the system which manipulates the signal into its final form. Whichever transport you have will work with the Benchmark though some transports might do a better job of getting the ones and zeroes off the disc and sending them downstream.

dcstep
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Re: A Rookie upsampling question

I agree totally with Jan and would add that the Benchmark will give you a significant improvement over almost any CDP under the $500 mark and many over that cost. I've got a expensive Playback Designs CD/SACD player that allows me to use it's exceptional DAC using the outputs from my Oppo and Pioneer universal players. The improvement in each is stunning, not being very muck less resolving than the result using the PD's own, expensive, internal transport. You're likely to experience a nice improvement by puttting the Benchmark in your system.

Dave

JIMV
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Re: A Rookie upsampling question

So the DAC1 itself does the upsampling and lets the user decide which upsampling rate he likes?

Jan Vigne
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Re: A Rookie upsampling question

That I don't know since I'm not familiar with the Benchmark unit. Normally the upsampling is performed by way of multiples of the original source's sampling rate. CD's at 44.1kHz can be upsampled to 88.2kHz or another multiple of the original 44.1 kHz rate. Other digital sources with sampling rates higher than 44.1kHz would be performed in multiples of their original sampling rate. Converting the original sampling rate to an unrelated upsampled rate has the potential for problems. How does Benchmark describe their upsampling procedure?

scottgardner
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Re: A Rookie upsampling question

Here is my (limited) understanding:

Upsampling can be useful if processing in digital is to take place. This is similar to video editing. You won't get any new information by doing it but you will have more information to work with while it is being modified.

Converting to a higher bit rate before adjusting volume has a much larger benefit. Think of it as a ruler. If you have 12bits (inches) then your ability to measure is limited to inches. If you take that same ruler and chop it into 24bits the your ability to measure has doubled. No new information has been added but your ability to adjust its "volume" is now more precise (half inches vs whole inches).

Here is a great thread on the RME forum where a couple engineers get involved to explain it in more detail: (pay particular attention to Daniel Fuchs's posts)

http://www.rme-audio.de/forum/viewtopic.php?id=3194

JIMV
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Re: A Rookie upsampling question

Alas, my question is not about the value or lack thereof of upsampling but how the process works on an outboard DAC. If the signal from the CD player being used as a transport sends the bit stream to the DAC un-upsampled and the DAC does watever upsampling there is, that is one thing. If the CD player sends an up-sampled data stream to the DAC and the DAC simply recognizes it, that is another. My existing CD player does not upsample but the DAC I want to buy is capable of 24/192, will my system produce upsampled sound or do I need to buy a new transport???

scottgardner
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Re: A Rookie upsampling question

The main benefit is in the bit gain 16->24 the higher sampling rate is irrelevant.

mrlowry
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Re: A Rookie upsampling question

In general, if the source is CD the digital output of the CD player is 16 bits 44.1kHz and the upsampling is all done in the DAC. If this weren't the case there would be problems hooking up the digital outs of CD players to DACs that can't accept more than 16/44.1. The upsampling DAC's for the most part can accept higher bit rate inputs so that they can decode digital files from the high resoulution download services. Most DVD players can output higher resolution than the 16/44.1, but the information has to be on the disc for them to do so.

scottgardner
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Re: A Rookie upsampling question

Thanks mrlowry.

I misunderstood the original question. What mrlowry says is true and is more related to your question. I didn't mean to take the discussion in the wrong direction.

JIMV
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Re: A Rookie upsampling question

I was not clear as I really am not familiar with this process. This will be the first change to my source in over 8 years so new technology is, well, new to me.

Elk
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Re: A Rookie upsampling question


Quote:
So the DAC1 itself does the upsampling and lets the user decide which upsampling rate he likes?


No.

The Dac1 runs at a fixed 110 kHz sample frequency. All digital data it receives is either downsampled (from 176 kHz or 192 kHz) or upsampled (from 32 kHz through 96 kHz).

This rate is used as Benchmark believes that its DAC chip works best at this frequency.

JIMV
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Re: A Rookie upsampling question

Thank you for the most clear and to the topic response I have received to my question thus far. That I understand.

Elk
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Re: A Rookie upsampling question

Cool.

Many other DCS do similar things. For example, some upsample everything to 300k+ to a lowest common denominator of the sample rates the DAC recognizes, and then goes from there.

I find interesting that the these do not typically say anything about upsampling. Apparently upsampling is no longer seen as a magic bullet.

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