question.. Will the 8-bit DAC produce good quality sound ?

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drdigital

Joined: 13 Apr 2009
Posts: 28

20 Apr 2009 17:49 audio dac parallel 8bit

Hi All ,
I asked many questions last 2 days about making audio or wav player and I'm still in the analysis phase.
I have now one clear question will determine the technique to use in generating sound from microcontroller (DAC or PWM) .

I got that using DACs in generating sound is better but still don't know why.

my question is will 8-bit Parallel DAC (DAC0800 or DAC0808) be able to generate a good quality sound ?If yes, will I need any other stuff to do the job?. if no, what's your suggestions to handle this ?

I intend to play wav files and will determine its specs as i need and as the hw limitations permit.

GSM Man

Joined: 15 Apr 2009
Posts: 357
Helped: 46
Location: New Jersey, USA

20 Apr 2009 19:09 question.. Will the 8-bit DAC produce good quality sound ?

You really need to nail down your requirements - lack of good requirements is bound to derail your project, whether you are a hobbyist or pro.

What does "Good Quality Sound" mean to you? What is the bite rate of your files? The quality of the sound is dependent on the bit rate- an output at 8kbps is not going to sound as good as a output at 128kbps, regardless of what techniqwue you use to output it.

Can a DAC prodcue "Good Qaulity Sound" - of course. Should you use DAC output or PWM - that depends more on what your other requirements are than on the quality of the output.

drdigital

Joined: 13 Apr 2009
Posts: 28

20 Apr 2009 19:19 question.. Will the 8-bit DAC produce good quality sound ?

Ok , Thanks.

"good quality sound" means sound of a song that I can hear without saying this song sound is bad, without noise .That's it.

Here is my progress till now :

I want to make an audio player.
here are the specs, what I got from search engines and forums and what I miss.

==>File Type to Play
.WAV - PCM - 8-bit - mono . Is that suitable for generating good quality sounds Smile

?
what internal uC memory requirement to play it ?

==>I will use 8-bit Parallel DAC (DAC0800 or DAC0808)
Is that suitable ? Is it better that using PWM and why ? any other suitable suggestions ? What's beside this DAC required ?

==>I will store the audio files in MMC card
I need a uC with SPI interface . any thing else ?

== >I suggested ATmega162 to be my uC.
Is it suitable ? any other better choices from the list here http://ram-e-shop.com/index.php?cPath=21_23?
is there a 8051 version can do this ?
how to achieve the sampling rate ?

I didn't use AVR before, I used 8051 instead (AT89s52).But I'm ready to start learning it.

FvM

Joined: 22 Jan 2008
Posts: 5154
Helped: 766
Location: Bochum, Germany

20 Apr 2009 19:47 question.. Will the 8-bit DAC produce good quality sound ?

In a short, an eight bit DAC or typical low resulution PWM can't provide good sound quality. I would consider some recent audio codec chip. They have programmable sample rates starting from 8 kHz and resolutions from 16 bit. Cause mp3 sets a standard for the data rate versus quality trade of, it's difficult to compete for a system not utilizing compression. You may of course prefer uncompressed digital audio (e.g. 44 kHz 16 bit PCM), then it's pretty easy. But a standard (slow) 8051 can't handle the data rate.

GSM Man

Joined: 15 Apr 2009
Posts: 357
Helped: 46
Location: New Jersey, USA

20 Apr 2009 20:07 Re: question.. Will the 8-bit DAC produce good quality sound

drdigital wrote:

"good quality sound" means sound of a song that I can hear without saying this song sound is bad, without noise .That's it.

That's a pretty weak specification, and certainly hard for anyone else to measure. Maybe you should look on the internet to find a program that will allow you to play back audio with various parameters to see what your requirements really are.

BTW - what is driving your requirmeents? In your other post I suggested you look at CODECs and you said that wasn't an option? Why, is this a class assignment?

drdigital

Joined: 13 Apr 2009
Posts: 28

21 Apr 2009 1:54 Re: question.. Will the 8-bit DAC produce good quality sound

FvM wrote:

Ok , What If we considered this (e.g. 44 kHz 16 bit PCM). what the requirements to do it without CODEC chip ?

@GSM MAN :
It is a class project .I just think adding codecs will make the job harder and will take more time to study the chip and interfacing it.I want is as simple as possible to get in completely works in about 14 days including other projects beside it Very Happy

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FvM

Joined: 22 Jan 2008
Posts: 5154
Helped: 766
Location: Bochum, Germany

21 Apr 2009 6:35 Re: question.. Will the 8-bit DAC produce good quality sound

There are different CODECs available. Ranging from programmable AD/DA front ends up to MP3 or multi standard decoders (as suggested by other constributors). A fixed resolution stereo audio DAC (16 Bit/ 44 kS/s) would provide analog quality according to the CD digital audio format. These DAC have usually serial interfaces (SPI or similar), to my opinion they are easy to handle, but an unskilled programmer may think different about it...

Generally, you should test, that the processor and it's data storage and DAC interface can handle the throughput. This can be tested without having a DAC or a functional analog circuit. As said, I don't expect that the said 8051 can do.

If the processor is already given for your project, you must go the other way round: Determine the throughput, try to minimize software overhead and select the audio standard and DAC according to the capabilities. (and claim, it's high quality...)

drdigital

Joined: 13 Apr 2009
Posts: 28

21 Apr 2009 11:30 question.. Will the 8-bit DAC produce good quality sound ?

I can choose my processor as I want.
So could you please suggest the components that will work well together. uC , DAC , etc

Thanks for your replay

Added after 25 minutes:

by the way I also need to interface MMC card . So will the SPI interface ?