moktan said:
anyway my last query is this: the DAC will cost 100UK pounds..the CD PLAYER about 160UK pounds...will the (about) Rs5000/- cost differential justify the 'superior' sound that one may get from the latter purchase or does it make more musical and economic sense to buy the DAC and then use it to get more juice out of my existing DVD player...
Moktan, please understand that any audio device (CDP, DVD, amps) that has digital input and analogue outputs will have a DAC inside. Now why add an external DAC? To improve the sound of your
existing devices. If you are going to buy a new device, does it make sense to buy another inexpensive device and try to improve it's quality?
Let us look at the options we have.
1. I have a universal DVD player connected to a reasonably good music system. I want to use the DVD player for music also. Remember a budget DVD player is optimised for decoding multi channel sound and video signals. It is handling a minimum of 6 audio channels at any time. The manufacturers are under pressure to keep the price low. So something has to be compromised, and it usually is the stereo or music part. The front two channels are treated the same way as all other channels. In this situation, a good DAC will go a long way in improving the sound for playing music.
2. I have a HT system, a music system, and lots of CDs. In addition I am converting all my CDs to digital files in compressed or uncompressed formats. I have a HT system in my living room where all the devices are stored. I have also set up a small music system in my bedroom, or let us say a high end music system also in my living room. In this situation I need to have a DAC to play all the files from my computer system. As I am doing this, I can also use the DAC to improve the sound from my CDP, and DVD Player. Here again, if you buy something like a Squeezebox or a Sonos system, they have excellent DACs. But if I use a PC based wireless network, I would need a DAC.
3. I have a very good DVD Player, and am looking to buy either a good CDP, or a DAC Here the decision becomes difficult. You have to start looking at your long term plans and go for or avoid a DAC.
As Moserw has said, audio nirvana or superior sound is very difficult to quantify or justify. Just to give you an example, when I was auditioning the Audire systems in Coimbatore, I noticed that there was a Benchmark DAC1 in the chain. For years I have read about the DAC1, and literally lusted after it. It has been there in my list of must buys. And whatever music I heard from the system sounded wonderful. So when one of the Audire guys said he has heard better DACs, all my dreams were shattered.
I have heard systems costing 20,000 to as much as 20 lakhs with and without DACs. They all sounded nice in their own rights. Will I be able to say one is better than the other? I will be lying if I say yes without a number of conditions added to that statement.
If you are looking to improve the sound of your system, it is very difficult to answer whether a device will vastly improve the sound or provide superior sound. Can you list what all you are missing from your present system. Have you heard other 'improved' systems. Have you heard the same song in multiple systems and are able to clearly make out what is missing and what is not? Have you heard a same song 100s of times and do you recognise each and every single nuance of the song? When does a instrument start, what is it's tone?
Why am I saying this? There are two ways to listening to music. One is when you are doing a lot of things, and you want music to be playing in the background. When you want to listen to music before going to sleep. When you want to listen to some romantic or peppy numbers to change your mood. In this situation, a decent sounding system is more than enough.
The other situation is when you are am music buff, and you want to listen to music with your eyes closed, no external distraction, no external sound, and your mind focussed on the music. When you know what songs are contained in each CD. When you are very familiar with some of the songs that you listen to regularly. When you know to the second when a tome will change, when an instrument will start, or when the singer will take a deep breath. In this situation, you have to use your ears, listen to a lot of systems, and decide which combination sounds best for you within the budget you have.
So which group do you belong to? Your decision to buy something will depend upon that.
Moserw said:
I really don't know. What I do know is upmixing i.e. taking 2 channel streams and pumping them into 5.1 or 7.1 or even taking 5.1 and outputting in a 7.1 system. Its all done by the AVR. From what I understand oversampling is a more complex process which my engineer wife should understand more easily...
In plain English (from what I know and I am not really an engineer so if someone knows better they should be able to better explain)...
Upmix - Take stereo and output in 5.1 or 7.1. (i.e. anything higher)
Downmix - Take 5.1 and output in stereo (i.e. anything lower).
I am open to correction here and also willing to learn if someone has anything more to add...
Though these terms may mean the same, and can be used either way, there are simple guidelines to differentiate between the use of the terms oversampling and upsampling
In the transfer process between digital and analogue domains, oversampling is used to describe a step when a sample of data or signal is sampled or read much above the frequency that is actually specified or required. This involves multiplying the sampling frequency by an even number such as 2, 4, 6 or 8. So when you take a Redbook CD and over-sample it at 8x, you are increasing the base rate from 44.1KHz to 352.8KHz. In this case you introduce 7 new samples between 44.1 and 352.8KHz. What are these samples? Are they just empty? Well yes and no.
For one, a analogue signal is a smooth curve. When converted to digital this becomes a stepped stair-like curve. When you are converting back to analogue you recreate the original smooth curve by calculating the positions of the smooth curve from between the digital steps through a process of approximation. Oversampling increases the number of steps and brings them closer to each other making the process of approximation more accurate and smoother.
Secondly, it has also been observed that when you convert from analogue to digital, phantom or echo signals are created which are placed at frequencies higher than the sampled frequency. These are also called images of the base data. In a 44.1kHz system, according to the Nyquist rule, the base signal extends from 0Hz to 22.05kHz. The first echo or image is inverted and extends from 44.1kHz down to 22.05kHz, the second image extends from 44.1kHz to 66.15kHz, and so on. Oversampling is used to identify these echoes and remove them from the output signal.
Thus oversampling is used to help the DAC work more linearly or smoothly. Oversampling also helps the last step in the DAC process - that of the reconstruction filters. Oversampling helps remove aliases which are distortions or noises that are introduced by the sampling process. Without over sampling, reconstruction filters have to work in a brutal manner, by simply cutting off some frequencies called stop-band rejection. With oversampling, these filters have more data to work with and create a smoother analogue curve.
Oversampling is done in both DAC and ADC processes.
Upsampling is generally done only in the DAC process. Here the data stream is stretched by interpolation. If you remember, I mentioned above the process of creating more data points in the digital curve. Interpolation does this using a process called polynomial curve fitting. When this is done in small non-integer steps (such as from 44.1KHZ to 48Khz) it is called upsampling.
This is what Jeff Kalt. Founder of Resolution Audio has to say about up and over sampling.
"From recent usage, I can only conclude that upsampling is any technique that increases the sample rate, for example from 44.1 to 96 kHz. Oversampling, in contrast, is a form of upsampling where the rate is increased by an integer multiple, that is, 4x, 8x, etc. For audiophile purposes, both processes are used for one reason: to reduce the artifacts of the digital to analogue converter. No new information is created -- once the original has been sampled at 44.1 kHz, anything above 22 kHz is lost forever. The whole idea of upsampling is just to make the d/a converter behave more ideally and introduce fewer artifacts into the analogue audio signal."
spirovious said:
Can you tell me abt Parasound as company & it's DAC in perticular?
Parasound is a very respected company. The company has kept away from competing in the narket to ensure they deliver superb products. I have already written to you about the DAC, and as mentioned above, my only worry about the Parasound DAC is it's age.
Cheers