CDP vs DAC (of same series)

[krishpiscean]

Getting back to understand the fundas much clearer.

From the same series,

1. Which one would have better sound CDP or DAC.
2. Is the same DAC used in CDP too ?

For example Musical Fidelity at AP, M1 DAC vs M series CDP.

I see lot of good offers in SG second sale for rega/audiolab CDPs but not for DACs. If convenience and CD buying are ruled out, woudl CDP match or outbeat the DAC.

 

[Shivam]

In the example of Musical Fidelity M series, the DAC sounds better than the player..... ( I am quoting from what others have told me ).

I use a new DAC now instead of upgrading my ageing musical fidelity player. The player acts as a transport.

 

[aashish351]

There is no general rule... It depends on the comparison of the inbuilt DAC and the outboard DAC in question. A high end CD player may sound better than a mid-end DAC. I have recently added a Valab Non-Oversampling DAC to the Sony Blu-ray player and there is considerable improvement in sound quality. But this is a budget CDP + Budget DAC. A better CDP like say, Marantz CD6004 may sound better.

 

[BLASTO]

There is also (24bit/192khz) upsampling that need to taken into consicderation.
The M1 DAC in question has upsampling capability while the MF M3 CDP does not have. (M6 CDP has).
M1 DAC sounds better than the M3 CDP but Iam not sure of the M6CDP.
The A1008 CDP was also more or less same as M1 DAC. This I did A/B comparison. But an extended audition may change views.

For eg: My Musichall CDP did not sound as impressive as M1 DAC in A/B comparison. But on extended audition, it is as good or even better in some songs. M1 DAC has an edge on vocals and the Musichall CDP has an edge on soundstage. So different songs excell on these in a different way. Both are upsampling BTW.

BTW, The rega DAC is non-upsampling DAC. Something to keep in mind.

 

[ravi_d]

Up-sampling is not necessarily better. Its a technique to add information which is not there in the source by using some algorithms.

 

[gryph0n]

Up-sampling is not necessarily better. Its a technique to add information which is not there in the source by using some algorithms.

No sampling technique/DAC/algorithm can add information that isn't already present in the source.

The reason for up-sampling is that it makes filtering, anti-aliasing etc. easier for the DAC. Basically it makes the DAC designer's life easier, but it won't add anything to the source material.

As you've pointed out, a upsampling DAC isn't necessarily better, or for that matter a non upsampling DAC too isn't necessarily better. It all depends on how good the implementations are.

 

[ravi_d]

No sampling technique/DAC/algorithm can add information that isn't already present in the source.

The reason for up-sampling is that it makes filtering, anti-aliasing etc. easier for the DAC. Basically it makes the DAC designer's life easier, but it won't add anything to the source material.

As you've pointed out, a upsampling DAC isn't necessarily better, or for that matter a non upsampling DAC too isn't necessarily better. It all depends on how good the implementations are.

I'm just trying to understand the terms up-sampling and over sampling. It would be great if you can explain a bit further on these.

 

[gryph0n]

I'm just trying to understand the terms up-sampling and over sampling. It would be great if you can explain a bit further on these.

My understanding is that they are very closely related.

OverSampling: This is a multiple of the original frequency. Eg, 44.1kHz would be oversampled to 88.2kHz (2x the original), or to 176.4kHz (4x the original).

UpSampling: This is the original signal converted to an arbitrary target frequency. Eg, 44.1kHz would be upsampled to 96kHz or 192khz.

 

[ravi_d]

My understanding is that they are very closely related.

OverSampling: This is a multiple of the original frequency. Eg, 44.1kHz would be oversampled to 88.2kHz (2x the original), or to 176.4kHz (4x the original).

UpSampling: This is the original signal converted to an arbitrary target frequency. Eg, 44.1kHz would be upsampled to 96kHz or 192khz.

When you say the source sample rate is 44.1kHz that means the source has a sample every 1/44,100 th of a second (or only 44100 samples are sent out every second). When you say sample rate as 96kHz there should be 96000 samples every 1 second.
During over-sampling from 44.1kHz to say 96kHz when the source has a sample every 1/44100 th of a second how the DAC was able to get a sample every 1/96000 th of a second? So the additional samples required to over sample are constructed using interpolation during up-sampling. These new samples are added by the component which does up-sampling and doesn't come from the source.
I'm not sure if I got it right.

 

[mbhangui]

When there is no data, you cannot add data. Adding data will simply color the music.
Oversampling involves multiplying the sampling frequency by a whole number, usually between 4 and 32, but sometimes higher, and is designed to let the DAC work in a more linear fashion.

Upsampling is where the datastream is stretched out by interpolation and is typically used to refer to large changes in sampling rate such as from 44.1khz to 192khz.

Oversampling is something to do with Digital to Analog conversion. The effects of oversampling at the DAC are advantageous to the design of the analog reconstruction filter that must be built. By having a high sample rate out of our DAC we can use a very simple, gentle analog filter to reconstruct our analog filter. This is important since we will be able to design an analog filter that is not only cheap hardware wise, but also has a nice linear phase response over the passband.

Upsampling differs from oversampling in that upsampling is between the transport and the DAC. In the case of the Lite DAC 39, it sits between your transport and a DAC like the DAC 60 or DAC 38. In this case the DAC 39 feeds the DAC 60 a 96 Khz signal instead of the 44.1 kHz. In theory, when a superior upsampler is mated with a DAC that can handle the upsampling, the true 96kHz 20 bit processing can be achieved. The resulting filtering process operates in a linear fashion which yields better sound quality. So, it has to be a careful match. An upsampler should only be used with a DAC capable of handling the high sample frequency."

Afaik oversampling is done at the hardware level only, upsampling in both, software and hardware.

Read this Link.

 

[gryph0n]

When you say the source sample rate is 44.1kHz that means the source has a sample every 1/44,100 th of a second (or only 44100 samples are sent out every second). When you say sample rate as 96kHz there should be 96000 samples every 1 second.
During over-sampling from 44.1kHz to say 96kHz when the source has a sample every 1/44100 th of a second how the DAC was able to get a sample every 1/96000 th of a second? So the additional samples required to over sample are constructed using interpolation during up-sampling. These new samples are added by the component which does up-sampling and doesn't come from the source.
I'm not sure if I got it right.

I'm not an expert, but here goes:

When a signal is upsampled, the odd samples that aren't in the original signal are zero filled. When this passes through the filters, the original signal aliases because of the zero samples, but all the alias products are above 22.05 kHz, so the lowpass filter removes them.

In effect, the original signal gets reconstructed, but now with advantage of having gentler cut-off filters.

Without upsampling/oversampling, DACs would need much steeper filters.

http://www.dspguru.com/dsp/faqs/multirate/interpolation