X-Git-Url: http://pere.pagekite.me/gitweb/homepage.git/blobdiff_plain/aaf3a8d6ac3f87b3060fda22f11cb474d2e37af0..8a2e71b1dc05bc1f558ba3d691834cb53e979957:/blog/archive/2018/10/10.rss

diff --git a/blog/archive/2018/10/10.rss b/blog/archive/2018/10/10.rss
index 7a3b9faadf..380dd00c6e 100644
--- a/blog/archive/2018/10/10.rss
+++ b/blog/archive/2018/10/10.rss
@@ -3,13 +3,87 @@
 	<channel>
 		<title>Petter Reinholdtsen - Entries from October 2018</title>
 		<description>Entries from October 2018</description>
-                <link>http://people.skolelinux.org/pere/blog/</link>
+                <link>https://people.skolelinux.org/pere/blog/</link>
 
 	
+	<item>
+		<title>Measuring the speaker frequency response using the AUDMES free software GUI - nice free software</title>
+		<link>https://people.skolelinux.org/pere/blog/Measuring_the_speaker_frequency_response_using_the_AUDMES_free_software_GUI___nice_free_software.html</link>        
+		<guid isPermaLink="true">https://people.skolelinux.org/pere/blog/Measuring_the_speaker_frequency_response_using_the_AUDMES_free_software_GUI___nice_free_software.html</guid>
+                <pubDate>Mon, 22 Oct 2018 08:40:00 +0200</pubDate>
+		<description>&lt;p&gt;&lt;img src=&quot;http://people.skolelinux.org/pere/blog/images/2018-10-22-audmes-measure-speakers.png&quot; align=&quot;right&quot; width=&quot;40%&quot;/&gt;&lt;/p&gt;
+
+&lt;p&gt;My current home stereo is a patchwork of various pieces I got on
+flee markeds over the years.  It is amazing what kind of equipment
+show up there.  I&#39;ve been wondering for a while if it was possible to
+measure how well this equipment is working together, and decided to
+see how far I could get using free software.  After trawling the web I
+came across an article from DIY Audio and Video on
+&lt;a href=&quot;https://www.diyaudioandvideo.com/Tutorial/SpeakerResponseTesting/&quot;&gt;Speaker
+Testing and Analysis&lt;/a&gt; describing how to test speakers, and it listing
+several software options, among them
+&lt;a href=&quot;https://sourceforge.net/projects/audmes/&quot;&gt;AUDio MEasurement
+System (AUDMES)&lt;/a&gt;.  It is the only free software system I could find
+focusing on measuring speakers and audio frequency response.  In the
+process I also found an interesting article from NOVO on
+&lt;a href=&quot;http://novo.press/understanding-speaker-specifications-and-frequency-response/&quot;&gt;Understanding
+Speaker Specifications and Frequency Response&lt;/a&gt; and an article from
+ecoustics on
+&lt;a href=&quot;https://www.ecoustics.com/articles/understanding-speaker-frequency-response/&quot;&gt;Understanding
+Speaker Frequency Response&lt;/a&gt;, with a lot of information on what to
+look for and how to interpret the graphs.  Armed with this knowledge,
+I set out to measure the state of my speakers.&lt;/p&gt;
+
+&lt;p&gt;The first hurdle was that AUDMES hadn&#39;t seen a commit for 10 years
+and did not build with current compilers and libraries.  I got in
+touch with its author, who no longer was spending time on the program
+but gave me write access to the subversion repository on Sourceforge.
+The end result is that now the code build on Linux and is capable of
+saving and loading the collected frequency response data in CSV
+format.  The application is quite nice and flexible, and I was able to
+select the input and output audio interfaces independently.  This made
+it possible to use a USB mixer as the input source, while sending
+output via my laptop headphone connection.  I lacked the hardware and
+cabling to figure out a different way to get independent cabling to
+speakers and microphone.&lt;/p&gt;
+
+&lt;p&gt;Using this setup I could see how a large range of high frequencies
+apparently were not making it out of my speakers.  The picture show
+the frequency response measurement of one of the speakers.  Note the
+frequency lines seem to be slightly misaligned, compared to the CSV
+output from the program.  I can not hear several of these are high
+frequencies, according to measurement from
+&lt;a href=&quot;http://freehearingtestsoftware.com&quot;&gt;Free Hearing Test
+Software&lt;/a&gt;, an freeware system to measure your hearing (still
+looking for a free software alternative), so I do not know if they are
+coming out out the speakers.  I thus do not quite know how to figure
+out if the missing frequencies is a problem with the microphone, the
+amplifier or the speakers, but I managed to rule out the audio card in my
+PC by measuring my Bose noise canceling headset using its own
+microphone.  This setup was able to see the high frequency tones, so
+the problem with my stereo had to be in the amplifier or speakers.&lt;/p&gt;
+
+&lt;p&gt;Anyway, to try to role out one factor I ended up picking up a new
+set of speakers at a flee marked, and these work a lot better than the
+old speakers, so I guess the microphone and amplifier is OK.  If you
+need to measure your own speakers, check out AUDMES.  If more people
+get involved, perhaps the project could become good enough to
+&lt;a href=&quot;https://bugs.debian.org/910876&quot;&gt;include in Debian&lt;/a&gt;?  And if
+you know of some other free software to measure speakers and amplifier
+performance, please let me know.  I am aware of the freeware option
+&lt;a href=&quot;https://www.roomeqwizard.com/&quot;&gt;REW&lt;/a&gt;, but I want something
+that can be developed also when the vendor looses interest.&lt;/p&gt;
+
+&lt;p&gt;As usual, if you use Bitcoin and want to show your support of my
+activities, please send Bitcoin donations to my address
+&lt;b&gt;&lt;a href=&quot;bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&quot;&gt;15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b&lt;/a&gt;&lt;/b&gt;.&lt;/p&gt;
+</description>
+	</item>
+	
 	<item>
 		<title>Web browser integration of VLC with Bittorrent support</title>
-		<link>http://people.skolelinux.org/pere/blog/Web_browser_integration_of_VLC_with_Bittorrent_support.html</link>        
-		<guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Web_browser_integration_of_VLC_with_Bittorrent_support.html</guid>
+		<link>https://people.skolelinux.org/pere/blog/Web_browser_integration_of_VLC_with_Bittorrent_support.html</link>        
+		<guid isPermaLink="true">https://people.skolelinux.org/pere/blog/Web_browser_integration_of_VLC_with_Bittorrent_support.html</guid>
                 <pubDate>Sun, 21 Oct 2018 09:50:00 +0200</pubDate>
 		<description>&lt;p&gt;Bittorrent is as far as I know, currently the most efficient way to
 distribute content on the Internet.  It is used all by all sorts of
@@ -38,7 +112,7 @@ what the strange x-scheme-handler style MIME types in desktop files
 are used for.  By adding x-scheme-handler/magnet to the MimeType entry
 in the desktop file, at least the browsers Firefox and Chromium will
 suggest to start VLC when selecting a magnet URI on a web page.  The
-end result is that now, with the plugin installed in Buster og Sid,
+end result is that now, with the plugin installed in Buster and Sid,
 one can visit any
 &lt;a href=&quot;https://archive.org/details/CopyingIsNotTheft1080p&quot;&gt;Internet
 Archive page with movies&lt;/a&gt; using a web browser and click on the
@@ -70,8 +144,8 @@ activities, please send Bitcoin donations to my address
 	
 	<item>
 		<title>Release 0.2 of free software archive system Nikita announced</title>
-		<link>http://people.skolelinux.org/pere/blog/Release_0_2_of_free_software_archive_system_Nikita_announced.html</link>        
-		<guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Release_0_2_of_free_software_archive_system_Nikita_announced.html</guid>
+		<link>https://people.skolelinux.org/pere/blog/Release_0_2_of_free_software_archive_system_Nikita_announced.html</link>        
+		<guid isPermaLink="true">https://people.skolelinux.org/pere/blog/Release_0_2_of_free_software_archive_system_Nikita_announced.html</guid>
                 <pubDate>Thu, 18 Oct 2018 14:40:00 +0200</pubDate>
 		<description>&lt;p&gt;This morning, the new release of the
 &lt;a href=&quot;https://gitlab.com/OsloMet-ABI/nikita-noark5-core/&quot;&gt;Nikita
@@ -145,8 +219,8 @@ activities, please send Bitcoin donations to my address
 	
 	<item>
 		<title>Fetching trusted timestamps using the rfc3161ng python module</title>
-		<link>http://people.skolelinux.org/pere/blog/Fetching_trusted_timestamps_using_the_rfc3161ng_python_module.html</link>        
-		<guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Fetching_trusted_timestamps_using_the_rfc3161ng_python_module.html</guid>
+		<link>https://people.skolelinux.org/pere/blog/Fetching_trusted_timestamps_using_the_rfc3161ng_python_module.html</link>        
+		<guid isPermaLink="true">https://people.skolelinux.org/pere/blog/Fetching_trusted_timestamps_using_the_rfc3161ng_python_module.html</guid>
                 <pubDate>Mon, 8 Oct 2018 12:30:00 +0200</pubDate>
 		<description>&lt;p&gt;I have  earlier covered the basics of trusted timestamping using the
 &#39;openssl ts&#39; client.  See blog post for
@@ -251,8 +325,8 @@ activities, please send Bitcoin donations to my address
 	
 	<item>
 		<title>Automatic Google Drive sync using grive in Debian</title>
-		<link>http://people.skolelinux.org/pere/blog/Automatic_Google_Drive_sync_using_grive_in_Debian.html</link>        
-		<guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Automatic_Google_Drive_sync_using_grive_in_Debian.html</guid>
+		<link>https://people.skolelinux.org/pere/blog/Automatic_Google_Drive_sync_using_grive_in_Debian.html</link>        
+		<guid isPermaLink="true">https://people.skolelinux.org/pere/blog/Automatic_Google_Drive_sync_using_grive_in_Debian.html</guid>
                 <pubDate>Thu, 4 Oct 2018 15:20:00 +0200</pubDate>
 		<description>&lt;p&gt;A few days, I rescued a Windows victim over to Debian.  To try to
 rescue the remains, I helped set up automatic sync with Google Drive.