Go Back   Home > Forums > >

Software Tools SPICE, PCB CAD, speaker design and measurement software, calculators

Howto - Distortion Measurements with REW
Howto - Distortion Measurements with REW
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
Reply
 
Thread Tools
Old 13th October 2021, 07:59 PM   #1031
phofman is offline phofman  Czech Republic
diyAudio Member
 
Join Date: Apr 2005
Location: Pilsen
Behringer UM2 is a USB fullspeed (12Mbps) soundcard. It sends/receives data every 1ms. IMO that is the 1kHz signal you see in your spectrum, very typical for fullspeed soundcards. The measurement signal with this card should differ a bit from 1kHz so that the results do not overlap with the 1kHz USB interference.
  Reply With Quote
Old 13th October 2021, 11:03 PM   #1032
trobbins is online now trobbins  Australia
diyAudio Member
 
trobbins's Avatar
 
Join Date: Feb 2009
Location: Melbourne, Oz
xrk971, that shows how well many cheap soundcard interfaces can do the job as a basic audio tool (ie. allow practical assessment of distortion products and any other signals down at a comparatively low noise level) without having to be aesthetically pleasing to the eye with a subterranean and flat noise floor with no extraneous signals poking out. I'd even expect that loopback using its own DAC output would be similarly as good with REW, especially for distortion testing as harmonic cancellation can be deployed and a test frequency away from 1kHz can be used.
  Reply With Quote
Old 14th October 2021, 03:44 AM   #1033
xrk971 is offline xrk971  United States
Got Foam?
diyAudio Member
 
xrk971's Avatar
 
Join Date: Oct 2012
Location: Metro DC (Virginia)
Howto - Distortion Measurements with REW
I even tried using it as a DAC and the music coming out of it isn’t half bad. For $30, it’s got a lot going for it. There’s really no excuse saying measurement gear costs too much anymore.
__________________
XRKaudio Store // Manufacturer’s Forum
  Reply With Quote
Old 19th October 2021, 05:16 PM   #1034
drinkingcube is offline drinkingcube  United States
diyAudio Member
 
Join Date: Jan 2019
Finally got this working using a Focusrite Scarlet 2i2.


I think it was you, xrk, which suggested that you need to use T and R, not T and S, on a TRS for the input to the interface. After many attempts and finally reading the documentation *VERY* carefully, it seems the Scarlet 2i2 automatically configures itself to Line Input when you use a TRS (not TS) jack.



I was not able to get good distortion measurements using the direct out of the scarlet, decided to use my iPhone's DAC, seemed to work fine.



I did not use an attenuator, so max power I was able to send into this thing I believe is:


P = ( 9 * 9 ) / 8 = 10 W


It was fun playing around with the different gain stages: 2i2 preamp input, phone DAC, amplifier preamp.


Anyway, I am pleased with the results. Thanks for all the info in this thread!
Attached Images
File Type: png distortion_1W.png (51.4 KB, 82 views)
File Type: png distortion_10W.png (51.6 KB, 76 views)
  Reply to this post

Reply


Howto - Distortion Measurements with REWHide this!Advertise here!
Thread Tools

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
Distortion and Other Measurements ????? SyncTronX Equipment & Tools 8 29th April 2014 06:57 AM
Distortion measurements, THD, IMD-what card? Eugene Dvoskin Solid State 24 1st January 2011 06:11 PM
Distortion Measurements Nikon1975 Tubes / Valves 8 1st March 2010 12:57 PM
How to do IM distortion measurements? Conrad Hoffman Parts 1 28th May 2007 06:09 PM
Distortion measurements Vg Multi-Way 5 13th August 2004 11:32 AM


New To Site? Need Help?

All times are GMT. The time now is 10:42 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2021 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 13.64%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2021 DragonByte Technologies Ltd.
Copyright ©1999-2021 diyAudio
Wiki