Avid Pro Audio Community

Avid Pro Audio Community

How to Join & Post  •  Community Terms of Use  •  Help Us Help You

Knowledge Base Search  •  Community Search  •  Learn & Support


Avid Home Page

Go Back   Avid Pro Audio Community > Pro Tools Software > Tips & Tricks

Reply
 
Thread Tools Search this Thread Display Modes
  #31  
Old 01-13-2002, 11:36 AM
emilano emilano is offline
Member
 
Join Date: May 2001
Location: NYC
Posts: 525
Default Re: Protools 192k

Okay, so then to break it down a bit for the peeps, it seems like both Uminger and Nika are saying that there is relatively little to be gained from higher sampling rates as far as they can determine:

Here's the list of things that will occur when higher sampling rates are used (in theory). Please add any others I'm missing:
<UL TYPE=SQUARE><LI>Existing crappy plugins may sound better<LI>Plugins may be easier for engineers to create<LI>Plug ins may use less DSP but this gets transferred multi fold to the mixer so no savings in DSP<LI>Since beat frequencies are a phenomenon created IN (or perhaps BY) the ear, no advantage here because freqs higher than 20khz are NOT interacting as previously mistated (by me) on this thread. This by the way, stated by Nika, goes against what "The Apogee Guide to Digital Audio" says since it says that these higher frequencies would be able to intermingle to good effect when close miced and mixed. Who do you believe? (I'd put money on Nika)[/list]
Anyone have any others to add? Well Damn! What's all the fuss about then?

Well, if there's nothing else, perhaps the final question is the one about can people hear (or perhaps it would be better phrased as "sense in some way") freqs above 20khz? I will mention my source for where I heard that people can sense sound (and find pleasing) frequencies above 20 khz. It was in an article by my pal Dave Moulton from 1992 called "So Whats so good about Digital anyway?". He mentions a study by Japanese researches that demonstrated this was true at least up to 50 khz. After mentioning this research, Dave goes on to say that even though he takes this study as truth, he never let it stop him from making digital his medium of choice given all its other benefits and basically that it sounds good enough (great really) and that sometimes people go a little nuts trying to squeeze out the last bit of detail long after the returns start diminishing.
Reply With Quote
  #32  
Old 01-13-2002, 01:03 PM
Nika Nika is offline
Member
 
Join Date: Oct 2001
Location: Indiana
Posts: 826
Default Re: Protools 192k

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:<HR>Originally posted by Noiz2:


The filtering that happens at the output stage of the D/A averages between the steps created by your samplerate. A higher samplerate has smaller steps more information and therefore less averaging going on. Any "real" information that falls between the samplerate "steps" is lost so by it's nature a higher sample rate will give a more acurate picture of your original source.
<HR></BLOCKQUOTE>

There can't be any "real" information between the steps since it was bandwidth limited on the way in and throughout the system. Recognizing this, there is only one possible way for the intermediary points to be constucted with an FIR - the most accurate way.

If I tell you that a number sequence is going to not contain any interval larger than 1, and I give you 1, x, 3, x, 5, x, 7, x, 9, x, 11. Then there is only one possible solution for each of the intermediate numbers. Sure, you could say that providing the following solution will provide for less "guesswork", but is it really "guesswork", or "averaging" at all?

1, 1.5, x, 2.5, 3, 3.5, x, 4.5 etc. etc.

There is no benefit to providing the D/A with more data than is necessary for it to reconstruct a waveform properly. And if the human ear AND the A/D are both band limited then there is no benefit to providing additional out of band material for the D/A. It will not "give a more acurate picture of your original source" after the A/D's filter. And I would argue that the work of the A/D's filter is capable of being audibly transparent.

Nika.
__________________
Digital Audio Explained Now on sale!
Reply With Quote
  #33  
Old 01-13-2002, 01:04 PM
Nika Nika is offline
Member
 
Join Date: Oct 2001
Location: Indiana
Posts: 826
Default Re: Protools 192k

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:<HR>Originally posted by Noiz2:
I like to slow things down, way down, so it will make a diference to me.<HR></BLOCKQUOTE>

If this is something you do as an effect then sure, it will provide you with the ability to do more processing to your data.

Nika.
__________________
Digital Audio Explained Now on sale!
Reply With Quote
  #34  
Old 01-13-2002, 02:55 PM
Hardnox Hardnox is offline
Member
 
Join Date: Dec 2000
Location: Concord, CA, USA
Posts: 465
Default Re: Protools 192k

Read through this thread...interesting stuff. So let's cut through to what really matters (especially to digi). Are all you guys going to upgrade to new converters? If not now maybe eventually? We haven't seen the products yet, but with all of the technical knowledge expressed above...what's you answer? We may consider how much these things will go for if 888/24s have been in the 3 grand area.

I just got my PT system in July. When my sales rep invited me to digi's product show (biggest product announcement in 4 years) at the end of the month where they would be demoing these things I called him and asked "Great, what about the system I just bought?" He called back and said "You're fine." I do music...and he basically didn't think I needed it. He said "It's the logical next step for digi, to compete, and usually these are things you won't really need."

What about you folks...are you so fired up that you're looking at your budgets and bank balances going "Let's see how I can make this happen." I look forward to seeing what you think.
__________________
www.hardnoxproductions.com
Reply With Quote
  #35  
Old 01-13-2002, 02:57 PM
Hardnox Hardnox is offline
Member
 
Join Date: Dec 2000
Location: Concord, CA, USA
Posts: 465
Default Re: Protools 192k

Bye the way...my sales rep could not tell me what exactly the new thing is...we're just guessing what it will do just like this thread.
__________________
www.hardnoxproductions.com
Reply With Quote
  #36  
Old 01-13-2002, 03:47 PM
QuikDraw's Avatar
QuikDraw QuikDraw is offline
Member
 
Join Date: May 2000
Location: Azle, Texas, USA
Posts: 2,116
Default Re: Protools 192k

I must disagree with one of Nika's points:

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:<HR>
Originally posted by Nika:

The creation of these subtones is a characteristic of the ear, and the ear is unable to hear any subtone frequencies caused by inter modulation distortion if EITHER root component is above the audible frequencies of the ear. Thus, a 24kHz and a 25kHz tone will NOT create an aubible 1kHz tone. A 22kHz tone and a 15kHz tone will NOT create an audible 7 kHz tone.
<HR></BLOCKQUOTE>

This is simply not correct. If the creation of these subtones were a function of the ear, and are not an actual electrical component of the output signal resulting from the mixing of two tones, then the science behind that could be applied just as correctly to higher frequencies as well. If that were true then a superhetrodyne radio receiver would not work.

To simplify, a superhet combines radio waves from an antenna with a set Intermediate Frequency ocsillator and then filters out all but either the sum or the difference frequency, leaving only one of these (supposedly only produced in the human ear) subtones for further processing in the receiver.

No, these subtones, the sum and difference frequencies of the two mixed tones, are a real electrical component of the output signal. Mix two sine waves, both within range of your digital system, and also whose sum and difference frequencies lie within your digital range, and look at the result in a spectrum analyzer. You will see all 4 frequencies!

Mike
__________________
-- Mike
- HP Spectre x360 Convertible 14t-ea100 - 2.9 GHz (5.0 Max Turbo) i7-1195G7 32GB RAM, OLED 3k x 2k, Iris Xe Onboard Graphics
- Windows 11 - PT 2021.12
- PreSonus Quantum 2 - PreSonus Studio 24c - Mackie Onyx 1640i
- Samsung T3 and T5 SSDs - Various USB2/3 and Firewire HDDs
Reply With Quote
  #37  
Old 01-13-2002, 04:43 PM
Greg Malcangi Greg Malcangi is offline
Member
 
Join Date: Dec 1999
Location: UK
Posts: 511
Default Re: Protools 192k

Hi Nika,

A couple of years ago I was invited to a listening test to compare mixes created at 48k, 96k and 192k sample frequencies. It was a double blind test under laboratory conditions.

All of us could tell the difference between the 48k and 96k mixes but the difference between 96k and 192k was much less significant. Once the test was over we discussed what we had heard. The consensus, which matched my personal observations, were that at 96k as compared to 48k, the stereo imaging and positioning was much clearer, the low mids were much cleaner and more defined and the mix had a little more space and less harshness in the high mids and highs.

My theory for the differences are related to the brickwall filtering and the fact that at 96k the filter curve is much smoother and further outside the range of human hearing than at 48k.

As far as the theorectical side is concerned Nika, do you think that this whole message is complete bullsh&t or do you have any better explanation for my observations?

TIA,

Greg
Reply With Quote
  #38  
Old 01-13-2002, 05:09 PM
Nika Nika is offline
Member
 
Join Date: Oct 2001
Location: Indiana
Posts: 826
Default Re: Protools 192k

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:<HR>Originally posted by Hardnox:
Read through this thread...interesting stuff. So let's cut through to what really matters (especially to digi). Are all you guys going to upgrade to new converters? If not now maybe eventually? We haven't seen the products yet, but with all of the technical knowledge expressed above...what's you answer? We may consider how much these things will go for if 888/24s have been in the 3 grand area.

I just got my PT system in July. When my sales rep invited me to digi's product show (biggest product announcement in 4 years) at the end of the month where they would be demoing these things I called him and asked "Great, what about the system I just bought?" He called back and said "You're fine." I do music...and he basically didn't think I needed it. He said "It's the logical next step for digi, to compete, and usually these are things you won't really need."

What about you folks...are you so fired up that you're looking at your budgets and bank balances going "Let's see how I can make this happen." I look forward to seeing what you think.
<HR></BLOCKQUOTE>

Hardknox,

I am in a position of knowing what the new system is, in pretty complete detail. 192k does not excite me, but I am indeed budgeting for the new system because of the other advantages it has in store.

Does that help?

Nika.
__________________
Digital Audio Explained Now on sale!
Reply With Quote
  #39  
Old 01-13-2002, 05:19 PM
Nika Nika is offline
Member
 
Join Date: Oct 2001
Location: Indiana
Posts: 826
Default Re: Protools 192k

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:<HR>Originally posted by QuikDraw:
This is simply not correct. If the creation of these subtones were a function of the ear, and are not an actual electrical component of the output signal resulting from the mixing of two tones, then the science behind that could be applied just as correctly to higher frequencies as well. If that were true then a superhetrodyne radio receiver would not work.

To simplify, a superhet combines radio waves from an antenna with a set Intermediate Frequency ocsillator and then filters out all but either the sum or the difference frequency, leaving only one of these (supposedly only produced in the human ear) subtones for further processing in the receiver.

No, these subtones, the sum and difference frequencies of the two mixed tones, are a real electrical component of the output signal. Mix two sine waves, both within range of your digital system, and also whose sum and difference frequencies lie within your digital range, and look at the result in a spectrum analyzer. You will see all 4 frequencies!

Mike
<HR></BLOCKQUOTE>

Sorry, I should have been more specific.

I should have stipulated that this only happens in a non-linear system. In a linear system the distortion that causes these tones does not manifest until it hits the non-linearity of the ear. Thus, the properties we are discussing are indeed caused by the non-linearity of the ear, but that is not the only place that they can happen. IM distortion is a property of any non-linear system - including the air. But the non-linearity is so small on any of these systems that it is undectable by the ear.

With the systems that we are talking about, indications of IM distortion may indeed show up on a spectrograph, but will be undectable by the ear. As soon as both tones are in the ear's range, however, the distortion components become audible.

I hope that this clarifies the phrase of contention. If in doubt, try it.

Nika.
__________________
Digital Audio Explained Now on sale!
Reply With Quote
  #40  
Old 01-13-2002, 05:27 PM
Nika Nika is offline
Member
 
Join Date: Oct 2001
Location: Indiana
Posts: 826
Default Re: Protools 192k

[QUOTE]Originally posted by Greg Malcangi:
A couple of years ago I was invited to a listening test to compare mixes created at 48k, 96k and 192k sample frequencies. It was a double blind test under laboratory conditions.

We should clarify that your test did not compare 48k to 96k and 192k, but rather that it compared the differences on a specific box, with a specific set of filters and a specific design of A/D converter circuit. This is important to distinguish.

My theory for the differences are related to the brickwall filtering and the fact that at 96k the filter curve is much smoother and further outside the range of human hearing than at 48k.

Based on the differences you have explained, your conclusion is certainly logical.

Research that I have done indicates, however, that with today's processing power it is possible to design inaudible FIR filter circuits. Bob Katz did a fairly comprehensive test on this using FIR filters that were so DSP intensive that they had to happen in non-realtime on his sonic system. He then inserted the filters in at 22.05kHz, but on a 96kS/s file. According to him, noone has been able to discern the differences between the original file and the modified one.

The people at Sony Oxford also explained to me that they didn't make the Oxford converters 96kS/s capable because using their existing filters any difference over 44.1kS/s was indectable in laboratory conditions. I have a write-up on their testing procedures for these types of tests.

What this indicates to me is that it is indeed possible to manufacture an inaudible filter that will provide for audibly transparent sampling at 44.1kS/s. My personal choice would be that manufacturers work on this solution as opposed to taking the lazy solution of requiring ME to use more DSP so that they can have gentler filters. There is no reason that that filter has to be audible.

Clearly the biggest benefit to higher sampling frequencies is indeed that filter, but it is the high end boxes that already have good filters. It is the low end boxes where it is poorly done. This "advancement" will finally allow the low end boxes to compete more with high end boxes in terms of sound quality.

If I had my druthers I'd rather not use twice the DSP, half the tracks, half the recording room, etc. I'd rather just buy good converters and leave it up to the manufacturers of those converters to supply me with what I need. I'm surprised that the market as of yet is uninterested in taking this approach. I suppose it's good for the manufacturers who sell higher sample rate boxes, though?

Somebody in the converter industry asked me this question one day, also:

"If you were a converter manufacturer and wanted to sell higher sample rate converters...and if the difference was inperceptible...would you allow them to sound the same?"

Hmm.

BTW, which converters were they that you tried? I'm looking for converters right now, and I'll eagerly avoid those... [img]images/icons/smile.gif[/img]

As far as the theorectical side is concerned Nika, do you think that this whole message is complete bullsh&t or do you have any better explanation for my observations?

Only mostly bullsh&t. Clearly this allows cheap converter manufacturers to design better converters for less money. The better the converters the less the difference, and by the time it gets to the playback system for all but the audiophiles it's all lost anyway.

The 96k buzz is founded on .1% valid premise that, unto itself, is negatable. The remaining 99.9% is utter bovine fecal matter.

As for any other sources that can cause the distortion you speak of, yes. Many playback systems are not designed to handle data over 20kHz. By pushing 35kHz through these systems they can cause distortion components of their own, actually sounding a bit more "analog" if you will. This is an actual case in which higher frequencies can be destructive to the listening process.

Good comments, though.

Nika.
__________________
Digital Audio Explained Now on sale!
Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
192k oddities Norad155 Post - Surround - Video 4 03-02-2010 07:57 AM
Recording at 192K kestral Pro Tools TDM Systems (Mac) 3 06-10-2005 09:50 AM
McDSP and 192K.... john1192 Tips & Tricks 0 02-07-2002 09:50 AM
96k vs 192k I/O usinare Pro Tools TDM Systems (Mac) 7 02-06-2002 09:49 AM
Who wants some 192K? Rollerex General Discussion 0 01-26-2002 06:03 PM


All times are GMT -7. The time now is 12:19 PM.


Powered by: vBulletin, Copyright ©2000 - 2008, Jelsoft Enterprises Limited. Forum Hosted By: URLJet.com