Go Back   UG Community @ Ultimate-Guitar.Com > Instruments > Guitar Gear & Accessories
User Name  
Password
Search:

Reply
Old 10-11-2012, 08:58 AM   #1
MultiM
Registered User
 
MultiM's Avatar
 
Join Date: Jun 2012
sampling frequency in multi effects?

when I'm looking to buy a multi effect, should I look to it's sampling frequency?
I don't even know what the **** is a sampling frequency,
44khz good or not?
help please!
MultiM is offline   Reply With Quote
Old 10-11-2012, 10:00 AM   #2
NotTheMessiah30
UG Fanatic
 
Join Date: Sep 2012
Sampling frequency is how often the system will take a sample (think of this is a snap shot of the sound). 44KHz is 44000 samples per second. This is CD quality, generally speaking though the higher the sampling frequency the better the sound quality, although as you go beyond 44KHz the immediately perceivable difference starts to diminish a little.

I've never really used multi effects pedals but 44KHz would certainly seem adequate. I don't know if there are even others that use higher frequencies but two that are common to audio applications are 96KHz and 192KHz, so perhaps do some hunting and see if you can find any that use these, although I would expect you'd pay a premium for such pedals.

Last edited by NotTheMessiah30 : 10-11-2012 at 10:01 AM.
NotTheMessiah30 is offline   Reply With Quote
Old 10-11-2012, 11:20 AM   #3
henrihell
Registered User
 
henrihell's Avatar
 
Join Date: Oct 2007
The sampling frequency only needs to be double (+ a tiny bit more) than the highest frequency on the instrument. And since you can't hear more than 20kHz you will have no trouble at all with a sampling frequency of 44kHz. I could explain why it is like this, but it'd be way too long for anyone to bother reading. So yeah, basically 44 is enough, but the higher, the better, because it will be more precise with the samples.
__________________
Quote:
Originally Posted by Anthropocentric
Your balls. You lost the right to them. Hand them over.


Quote:
Originally Posted by T00DEEPBLUE
What kind of person needs to have a Flying V shoved up their vagina?



Join The 7-String Legion! Now!
henrihell is online now   Reply With Quote
Old 10-11-2012, 11:32 AM   #4
|Long|
String Theory
 
Join Date: Oct 2007
Quote:
Originally Posted by henrihell
The sampling frequency only needs to be double (+ a tiny bit more) than the highest frequency on the instrument. And since you can't hear more than 20kHz you will have no trouble at all with a sampling frequency of 44kHz. I could explain why it is like this, but it'd be way too long for anyone to bother reading. So yeah, basically 44 is enough, but the higher, the better, because it will be more precise with the samples.

Er, well the higher the better is not correct. It's just wasted space. Nyquist says that you need twice the peak frequency to completely reconstruct the waveform. 44.1 Khz is twice 22.05 Khz. There already is a 'correction' in the sample rate to account of the real-time limitations. Furthermore, 22.05 Khz is also higher than the the audible spectrum, so yeah, 44.1 Khz is MORE than enough to completely reconstruct the signal. Higher sample rates can't improve what's already perfectly reconstructed.

There are people who think, know, like to think, or like to know that 96/192 K is superior, but there is nothing to back that up.
__________________
Hydroxic acid, kills thousands of people every year. Studies have shown lakes and rivers all over North America contain high levels hydroxic acid. Currently governments have taken no action against this life threatening chemical.
|Long| is offline   Reply With Quote
Old 10-11-2012, 11:45 AM   #5
MultiM
Registered User
 
MultiM's Avatar
 
Join Date: Jun 2012
thnx!
MultiM is offline   Reply With Quote
Old 10-11-2012, 01:58 PM   #6
gumbilicious
beginner
 
gumbilicious's Avatar
 
Join Date: Oct 2007
Location: on the road... again
Quote:
Originally Posted by |Long|
Er, well the higher the better is not correct. It's just wasted space. Nyquist says that you need twice the peak frequency to completely reconstruct the waveform. 44.1 Khz is twice 22.05 Khz. There already is a 'correction' in the sample rate to account of the real-time limitations. Furthermore, 22.05 Khz is also higher than the the audible spectrum, so yeah, 44.1 Khz is MORE than enough to completely reconstruct the signal. Higher sample rates can't improve what's already perfectly reconstructed.

There are people who think, know, like to think, or like to know that 96/192 K is superior, but there is nothing to back that up.


that is pretty much what he already said, you just added 'nyquist' and added an opinion about how you don't think any sampling above 2x the hearing range is a benefit.

first off, nyquist wasn't the only person who came up with this, that is why the sampling theorem also called the Whittaker–Nyquist–Kotelnikov–Shannon sampling theorum.

while i tend to agree with your analysis that is is kinda waste to sample anything above ~44 kHz i will at least admit to myself that is still an opinion.

the actual sampling theorem states:

"If a function x(t) contains no frequencies higher than B hertz, it is completely determined by giving its ordinates at a series of points spaced 1/(2B) seconds apart."

while we might only be able to hear up to ~20 kHz, there is still audio frequecies above 20 kHz in the signal. so if we don't extend the sampling range to include the entire audio signal and not just what we'll hear, then technically we are introducing aliasing and distortion to the sampled signal.

is this important? i hear it can be important when simulating hi-def reverb signals interacting with an environment.

but really, in the context of the question henrihell explanation was completely fine. there was no need to try to 1-up him by stating some technical stuff to back up your opinion to his detriment.
__________________
punk isn't dead, it's always smelled that way.

"A perfection of means, and confusion of aims, seems to be our main problem."
-ae

Last edited by gumbilicious : 10-11-2012 at 02:00 PM.
gumbilicious is offline   Reply With Quote
Old 10-11-2012, 06:26 PM   #7
|Long|
String Theory
 
Join Date: Oct 2007
Quote:
Originally Posted by gumbilicious
that is pretty much what he already said, you just added 'nyquist' and added an opinion about how you don't think any sampling above 2x the hearing range is a benefit.

My first line was that the "more is better" is incorrect. Everything else he stated was fine. There was no intent to "1-up", but to simply "correct" as to others reading it, they should be reading and understanding things correctly.

More is better is how the industrys has survived on selling snake-oil - much like 900$ HDMI cables.

Quote:
first off, nyquist wasn't the only person who came up with this, that is why the sampling theorem also called the Whittaker–Nyquist–Kotelnikov–Shannon sampling theorum.

It doesn't matter. It's common practice to call it Nyquist rate, or simply sampling rate.
__________________
Hydroxic acid, kills thousands of people every year. Studies have shown lakes and rivers all over North America contain high levels hydroxic acid. Currently governments have taken no action against this life threatening chemical.
|Long| is offline   Reply With Quote
Old 10-11-2012, 06:46 PM   #8
gumbilicious
beginner
 
gumbilicious's Avatar
 
Join Date: Oct 2007
Location: on the road... again
Quote:
Originally Posted by |Long|
My first line was that the "more is better" is incorrect. Everything else he stated was fine. There was no intent to "1-up", but to simply "correct" as to others reading it, they should be reading and understanding things correctly.

More is better is how the industrys has survived on selling snake-oil - much like 900$ HDMI cables.


very true, there is a bunch of snake oil when it comes to audio sampling. i was also going to draw attention to it, but you did more than a fine enough job.

i just thought with the realm at which the TS was asking a question, the responses above were sufficient. but you do raise a good concern

Quote:
Originally Posted by |Long|
It doesn't matter. It's common practice to call it Nyquist rate, or simply sampling rate.


it is one of my hang-ups when credit is due to many individuals instead of one, i can't seem to help but point it out. mainly it was the "Nyquist says" comment, the concept was 'discovered' independently by other very competent individuals as well. i have seen the concept referred to as "Cardinal Theorem of Interpolation Theory" as well.

but i will admit i am splitting hairs, and it isn't overly important to the overall conversation, but i like to indulge my exhausting tendencies every once in a while.
__________________
punk isn't dead, it's always smelled that way.

"A perfection of means, and confusion of aims, seems to be our main problem."
-ae
gumbilicious is offline   Reply With Quote
Reply


Thread Tools Rate This Thread
Rate This Thread:

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

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump



All times are GMT -4. The time now is 07:15 AM.

Forum Archives / About / Terms of Use / Advertise / Contact / Ultimate-Guitar.Com © 2014
Powered by: vBulletin Version 3.0.9
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.