Subject:Newbie to ACID: Project Properties (Instant ACID - JR)

Posted by: Jay Gladwell

Date:3/6/2005 6:49:02 PM

If I understood it correctly, the book suggests setting the sample rate at 48,000 and the bit depth at 24. However, I noticed that most of the loops in the Media Manager show having a sample rate of 44,100 and a bit depth of 16.

Will these differences create any kind of conflicts when it comes time to render? If not, what would be the advantage of settings higher than that of the original media?

Subject:RE: Newbie to ACID: Project Properties (Instant ACID - JR)

Reply by: JohnnyRoy

Date:3/6/2005 10:47:24 PM

The differences will not create any kind of conflict. The reason you want to manipulate audio at a higher sample rate and bit depth is because adding effects like reverb adds a lot of information to the sound. It is better to process this information at a higher rate and depth and then dither to a lower rate and depth than to work at the lower rate and depth and risk loosing information because there is no way to accurately represent it.

This is not unique to ACID but is a good rule of thumb in any audio application where you will be modifying audio with effects.

~jr

Subject:RE: Newbie to ACID: Project Properties (Instant ACID - JR)

Reply by: Jay Gladwell

Date:3/7/2005 4:22:46 AM

... It is better to process this information at a higher rate and depth and then dither to a lower rate and depth...

Sorry. I don't understand the last part of that statement regarding dithering to a lower rate and depth.

Subject:RE: Newbie to ACID: Project Properties (Instant ACID - JR)

Reply by: JohnnyRoy

Date:3/7/2005 5:35:18 AM

> Sorry. I don't understand the last part of that statement regarding dithering to a lower rate and depth.

If you work on 48Khz/24-bit and you are delivering your project on CD, you must dither your output to 44.1KHz/16-bit which is CD quality. If you are delivering your project on DV video, you must dither the bit dept to 16-bit because DV audio is 48Khz/16-bit. This is what happens when you select an output template that is different from the source format. ACID will dither for you or you can add the Sony Dither FX if you want more control over the process.

~jr

Subject:RE: Newbie to ACID: Project Properties (Instant ACID - JR)

Reply by: Illogical

Date:3/8/2005 12:50:07 PM

Is it just the mathematics of processing that are helped by the extra bits, or is the unprocessed sound actually improved in any way by switching to 24-bit?

thanks in advance

Subject:RE: Newbie to ACID: Project Properties (Instant ACID - JR)

Reply by: JohnnyRoy

Date:3/8/2005 7:22:34 PM

The unprocessed sound does not improve. It’s all in the math. The more information you sample, the more information you have to work with, the more accurate you can be. If you take a 16-bit sample and make it 24-bit it will not sound any better. If you process that sample at 24-bit and switch back to 16-bit, it may sound better than processing it at 16-bit because the processing was done with a higher level of precision.

~jr

Subject:RE: Newbie to ACID: Project Properties (Instant ACID - JR)

Reply by: pwppch

Date:3/8/2005 10:07:15 PM

Understand an important part here:

The project bit depth is the HARDWARE bit depth. Internally, ACID is working with everything in what is known as normalized-floating point.

All mixing and DSP processing is done in this format. What you end up hearing on your monitors is dependent on the quality of your D/A converters (and you analog signal chain after that of course.)

Finally, what you render to is the utlimate deciding factor in all of this. If you render (or burn directly to) CD, then some level of compression,dithering, or process (like our WaveHammer plugin) will get the most out of the bits that you are rendering to.

The only other thing to consider about bit depth is recording. 24 bits is better than 16 when recording. More dynamic range as well as being able to skip the compression stage on input (for the most part) are all benifits of increased bit depth. Depends on the material you are recording live as well as the A/D and "room" (ambiance and noise floor) you have to work with.

Peter