X-Git-Url: https://pere.pagekite.me/gitweb/homepage.git/blobdiff_plain/d65897bad371408370a2b3e82783242f35baefef..7e36d7f1ee3064b18e93a22e424476eb8b4e0b64:/blog/index.rss diff --git a/blog/index.rss b/blog/index.rss index 5dad2229b3..bfea166445 100644 --- a/blog/index.rss +++ b/blog/index.rss @@ -6,6 +6,80 @@ http://people.skolelinux.org/pere/blog/ + + Measuring the speaker frequency response using the AUDMES free software GUI - nice free software + http://people.skolelinux.org/pere/blog/Measuring_the_speaker_frequency_response_using_the_AUDMES_free_software_GUI___nice_free_software.html + http://people.skolelinux.org/pere/blog/Measuring_the_speaker_frequency_response_using_the_AUDMES_free_software_GUI___nice_free_software.html + Mon, 22 Oct 2018 08:40:00 +0200 + <p><img src="http://people.skolelinux.org/pere/blog/images/2018-10-22-audmes-measure-speakers.png" align="right" width="40%"/></p> + +<p>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'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 +<a href="https://www.diyaudioandvideo.com/Tutorial/SpeakerResponseTesting/">Speaker +Testing and Analysis</a> describing how to test speakers, and it listing +several software options, among them +<a href="https://sourceforge.net/projects/audmes/">AUDio MEasurement +System (AUDMES)</a>. 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 +<a href="http://novo.press/understanding-speaker-specifications-and-frequency-response/">Understanding +Speaker Specifications and Frequency Response</a> and an article from +ecoustics on +<a href="https://www.ecoustics.com/articles/understanding-speaker-frequency-response/">Understanding +Speaker Frequency Response</a>, 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.</p> + +<p>The first hurdle was that AUDMES hadn'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.</p> + +<p>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 +<a href="http://freehearingtestsoftware.com">Free Hearing Test +Software</a>, 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.</p> + +<p>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 include +in Debian? 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 <a href="https://www.roomeqwizard.com/">REW</a>, +but I want something that can be developed also when the vendor +looses interest.</p> + +<p>As usual, if you use Bitcoin and want to show your support of my +activities, please send Bitcoin donations to my address +<b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p> + + + Web browser integration of VLC with Bittorrent support http://people.skolelinux.org/pere/blog/Web_browser_integration_of_VLC_with_Bittorrent_support.html @@ -614,37 +688,6 @@ Medicine</a>. If you too want to track your own health and fitness without having information about your private life floating around on computers owned by others, I recommend checking it out.</p> -<p>As usual, if you use Bitcoin and want to show your support of my -activities, please send Bitcoin donations to my address -<b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p> - - - - - Privacy respecting health monitor / fitness tracker? - http://people.skolelinux.org/pere/blog/Privacy_respecting_health_monitor___fitness_tracker_.html - http://people.skolelinux.org/pere/blog/Privacy_respecting_health_monitor___fitness_tracker_.html - Tue, 7 Aug 2018 16:00:00 +0200 - <p>Dear lazyweb,</p> - -<p>I wonder, is there a fitness tracker / health monitor available for -sale today that respect the users privacy? With this I mean a -watch/bracelet capable of measuring pulse rate and other -fitness/health related values (and by all means, also the correct time -and location if possible), which is <strong>only</strong> provided for -me to extract/read from the unit with computer without a radio beacon -and Internet connection. In other words, it do not depend on a cell -phone app, and do make the measurements available via other peoples -computer (aka "the cloud"). The collected data should be available -using only free software. I'm not interested in depending on some -non-free software that will leave me high and dry some time in the -future. I've been unable to find any such unit. I would like to buy -it. The ones I have seen for sale here in Norway are proud to report -that they share my health data with strangers (aka "cloud enabled"). -Is there an alternative? I'm not interested in giving money to people -requiring me to accept "privacy terms" to allow myself to measure my -own health.</p> - <p>As usual, if you use Bitcoin and want to show your support of my activities, please send Bitcoin donations to my address <b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>