diyAudio - Entries for May 13, 2013
Go Back   Home > Forums > Blogs > My DIY projects

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
I returned to DIY electronics in 2009 after a 20 year pause by building a few kits to get in shape. This blog is for me to keep track of my progress.
Old

Measurements with a sound card

Posted 13th May 2013 at 10:08 PM by alexcp (My DIY projects)
Updated 7th September 2013 at 10:36 AM by alexcp (Updated for ASIO4ALL)

I am using a USB sound card for measurements. It's a pain, but I have nothing better yet.

The sound card is the E-MU 0204. I've chosen it for the specs:
  • Dynamic Range (A-weighted, 1kHz, min gain): 113dB
  • Signal-to-Noise Ratio (A-weighted, min gain): 113dB
  • THD+N (1kHz at - 1dBFS, min gain): -101.9dB (.0008%)

The sound card is intefaced to the real world by Pete Millett's sound card interface.

The software is SpectraPLUS 5.0 by Pioneer Hill Software (PHS). (No link because my antivirus says their web site is infected.) The software runs on an old MacBook running Windows 7 in Boot Camp.

The results do not seem to be affected by nearby computers, flurescent lights, switching power supplies, etc.

The results are affected by:
  • Windows Mixer settings (levels and sampling rates)
  • Software settings (levels and sample rate)
  • Grounding of the sound card, the interface, and the device under test

The greatest source of pain is...
Attached Thumbnails
Click image for larger version

Name:	E-MU 0204 loopback spectrum.png
Views:	292
Size:	37.4 KB
ID:	1055   Click image for larger version

Name:	E-MU 0204 loopback THD+N vs Freq.png
Views:	160
Size:	37.5 KB
ID:	1056   Click image for larger version

Name:	E-MU 0204 ATEST spectrum.png
Views:	141
Size:	37.1 KB
ID:	1057   Click image for larger version

Name:	E-MU 0204 ATEST THD+N vs Freq.png
Views:	169
Size:	37.5 KB
ID:	1058   Click image for larger version

Name:	NE5532 power amp spectrum.png
Views:	195
Size:	32.4 KB
ID:	1059  

Click image for larger version

Name:	NE5532 power amp THD+N vs Freq.png
Views:	326
Size:	31.9 KB
ID:	1060  
alexcp's Avatar
diyAudio Member
Posted in Instrumentation
Views 663 Comments 0 alexcp is offline
Hide this!Advertise here!

New To Site? Need Help?

All times are GMT. The time now is 12:35 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