Bybee Quantum Purifier Measurement and Analysis - Page 48 - diyAudio
Go Back   Home > Forums > General Interest > Everything Else

Everything Else Anything related to audio / video / electronics etc) BUT remember- we have many new forums where your thread may now fit! .... Parts, Equipment & Tools, Construction Tips, Software Tools......

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Closed Thread
 
Thread Tools Search this Thread
Old 6th September 2010, 11:36 PM   #471
Pano is offline Pano  United States
diyAudio Moderator
 
Pano's Avatar
 
Join Date: Oct 2004
Location: Kona, Hawaii
Blog Entries: 4
Having tried very hard to do the "subtraction" tests shown in the Nordost doc, I can tell you that they are fiendishly difficult. At least they admit as much in the doc. Getting the amplitudes exact and the the time right to the sample is much harder than you might think.
In fact I don't see how it can be done without a synchronized DAC and ADC. Even on short, simple sound files it's no walk in the park.

Too bad, as the idea holds a lot of promise. Just can't tell from that document what they did to overcome the speed bumps. They do seem to have taken them into consideration, but I don't see enough to be confident that things line up that well.
__________________
Take the Speaker Voltage Test!
 
Old 6th September 2010, 11:38 PM   #472
anatech is offline anatech  Canada
diyAudio Moderator
 
anatech's Avatar
 
Join Date: Jun 2004
Location: Georgetown, On
Hi Jack,
In addition to what SY said, there is a lack of detail on exactly what equipment was used. This can make a difference as any short coming in it's design can be affected by an external device. A power supply especially! There wasn't enough evidence presented to come to any conclusions. As I mentioned, with a defect design in equipment, you can make a difference depending on the connections and purity of the applied AC mains.

I can't say whether their cables are good or bad. What I can say is that there are probably situations where cable type and construction can "fix" a problem area.

As to test methodologies, the capture and subtract trace is a common procedure. I do it all the time with both an oscilloscope and spectrum analyzer. Those functions are built right in to the equipment. Nothing new or earth shattering about the tests they were running.

-Chris
__________________
"Just because you can, doesn't mean you should" my Wife
 
Old 6th September 2010, 11:42 PM   #473
anatech is offline anatech  Canada
diyAudio Moderator
 
anatech's Avatar
 
Join Date: Jun 2004
Location: Georgetown, On
Hi panomaniac,
Some post processing software allows you to align the curves. Certainly not a real-time thing though! Also, an FFT type record is pretty easy since the frequencies will (should) be the same. A time record is the more difficult case, and a time record with math done would be horrendous to do!

As I said, I commonly do this with a spectrum analyzer.

-Chris
__________________
"Just because you can, doesn't mean you should" my Wife
 
Old 6th September 2010, 11:51 PM   #474
diyAudio Member
 
tubelab.com's Avatar
 
Join Date: Jul 2005
Location: West Virginia panhandle
Quote:
As to test methodologies, the capture and subtract trace is a common procedure.
Capture and subtract is indeed possible on a scope if the two files are correlated, or captured at the same time. Capture and subtract after the fact on two different wave files that were not captured simultaneously is extremely difficult. If the clocks for the two files were not syncronized, there is no way that the samples will contain the same information. The error may be small, but it will vary every time you run the test.

I have been working on a way to start with a wave file ripped from a CD, play it in a high end DAW (Cakewalk Sonar) through a DUT using a 24 / 192 sound card, and capture the DUT output in the DAW. The two wave files can be correlated in time to compensate for delay and subtracted to show the error. This is still not perfect and the error is non zero and not repeatable with a plain wire under test. The errors are getting small though.
__________________
Too much power is almost enough! Turn it up till it explodes - then back up just a little.
 
Old 7th September 2010, 12:08 AM   #475
Cassiel is online now Cassiel  Libya
diyAudio Member
 
Cassiel's Avatar
 
Join Date: Sep 2004
Location: Madrid
A lot of armchair speculation going on here and a lot of bias. Exeric was right, everything but an open mind. I'm out.
 
Old 7th September 2010, 12:41 AM   #476
Pano is offline Pano  United States
diyAudio Moderator
 
Pano's Avatar
 
Join Date: Oct 2004
Location: Kona, Hawaii
Blog Entries: 4
That's all it takes Stalker? Jeez, that was swift. I don't even get it. I see the speculation - because we don't have results yet. But where is the bias, seriously?
 
Old 7th September 2010, 12:47 AM   #477
diyAudio Member
 
Join Date: Jul 2005
Location: Fairfield, IA
Default Test methods

Gentlemen:
Outside of the scope of their paper, in some of their latter announcements, Nordost claim that they ran the same tests on the same equipment months later at a different location, and the error differences showed up in exactly the same places. That is significant.

Yes I know, where's the peer review, etc.... but, guys... I've spent some time in the test equipment and signal analysis business, both as a user and apps engineer... and I do understand how to derive a difference signal using single shot storage scopes, repetitive and pulse averaging on HF test gear, using complex waveforms, studying reflections w high speed signal analyzers, etc. and applied it extensively in various fields of endeavor from medical to aerospace to low frequencies, including audio. And we extensively used signal subtraction and comparison with in real time and with repetitive functions. Because I had to deal with so many types of applications I became somewhat familiar with different testing methodologies and approaches.

And it is my feeling that there is something in this test methodology that merits more than a casual dismissal especially IF as Nordost says: the tests run at a different time in a different location matched exactly with the originals... the errors correlated, that is, they happened in the same places and with similar amplitudes....

well, uh, who cares about the scale? If it's small and repeatable and it CORRELATES with what we are HEARING, it means we are finding something we were previously MISSING in our measurements, no?

Please do not dismiss this method, I believe it has some real potential.

Yes Chris, I believe your power supply comments are correct, when it comes to power supplies, very few are any good and it is easy to see differences here.

So, if Acuity's results were based only on the PS, I would say you are totally correct. But the tests were done in sequence, with each element and then as a whole....
and they stated they showed differences for EACH of interconnects, speaker cables, power chord, power conditioner and platform. And according to them each showed a consistent difference.

SO... before we dismiss this type of testing because it's difficult to get proper mathematical correlation (Notice the wording: I said difficult, not impossible, apparently.)

How about checking with the guys that invented the methodology to see if they would volunteer some info on how to do this (not too likely if it's proprietary code), or even get a group funding together to have him check on a Bybee?

Here's the guy:

Dr Gareth Humphries-Jones of Acuity Products, a Doctor of Applied Mathematics and a specialist in signal processing algorithms as applied to high performance sonar and radar systems).

Wanna go out and check on them? I did, here's Gareth's info:

Gareth Humphreys-Jones - United Kingdom | LinkedIn
and here...
Background

If I get the gist of it, he's a real whiz with mathematical processing and signal analysis and he has loads of aerospace contracts.

So IF what they said about their test method actually happens to be true... and it looks very interesting to me... the Bybee and similar boxes would be good candidates to check out and see if they have similar effects to the Nordost gear... and maybe we can all benefit from learning more about this.
 
Old 7th September 2010, 12:57 AM   #478
Pano is offline Pano  United States
diyAudio Moderator
 
Pano's Avatar
 
Join Date: Oct 2004
Location: Kona, Hawaii
Blog Entries: 4
No one is dismissing the method out of hand. I think that's unfair. We have simply noted that it's rather difficult to do. And the the Nordost paper does not supply enough detail to determine what steps were taken to overcome the difficulties. It's not so much the testing, as it is the reporting.

Please feel free to contact Dr Humphreis-Jones. There were a number of folks here willing to put $ into the pot for Bybee purchase, perhaps the same would go for testing it we are satisfied the tests are worthwhile.
__________________
Take the Speaker Voltage Test!
 
Old 7th September 2010, 01:03 AM   #479
bwaslo is offline bwaslo  United States
diyAudio Member
 
bwaslo's Avatar
 
Join Date: May 2006
Location: Portland, Oregon!
Quote:
Originally Posted by anatech View Post
Hi panomaniac,
Some post processing software allows you to align the curves. Certainly not a real-time thing though! Also, an FFT type record is pretty easy since the frequencies will (should) be the same. A time record is the more difficult case, and a time record with math done would be horrendous to do!

As I said, I commonly do this with a spectrum analyzer.

-Chris
I've released freeware software to do such alignment and subtraction of audio time domain wav files (along with the recording functions, and even sample rate matching, and an option for frequency response equalization). It's been brought up from time to time in these forums, but for those not familiar with it --
"Audio DiffMaker" (freeware)
Audio DiffMaker

It operates in both time domain and frequency domain, as most appropriate for each function. And at sample rates to 192kHz and resolutions to 24bit. Maybe this would be another good way to check the Bybee filters with.
 
Old 7th September 2010, 01:31 AM   #480
wwenze is offline wwenze  Singapore
diyAudio Member
 
Join Date: Mar 2008
I was just looking for this kind of thing a while ago, thanks a lot!
 

Closed Thread


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Info on Bybee Quantum Purifiers needed Peter Daniel Everything Else 68 19th December 2012 09:28 AM
Bybee Quantum Purifier Experience. mrfeedback Everything Else 321 27th August 2010 10:41 PM
diy bybee quantum purifiers? mbl Power Supplies 549 16th April 2010 11:38 PM
measurement and analysis tools D_Dubya Full Range 12 31st May 2008 03:07 PM


New To Site? Need Help?

All times are GMT. The time now is 08:45 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2