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New since 11.10.2001 (Version of 13.03.2003):

• A new page with Tips for beginners in loudspeaker development was added.
• The main page was slightly modified to allow direct access to the 3 different information levels (Beginners, Impatients and Advanced (in German only))
• On the projects page the section about the Measuring microphone had to be reworked completely as since 2002 CONRAD sells a "new" kit with very different properties under the same order number.
• The table of content (German) of my Test-CD (incl. signals for the subjective evaluation of room resonances) is as new as the manual for a small circuit that simplifies impedance measurements with SB_OCT.
• You may find 2 new programms for statistical analysis and sample by sample comparison of WAV files. Moreover a hint for a very elegant trick for ripping of WAV files.
• What you always wanted to know about Emphasis/Pre-Emphasis (= digital trebble lift or sink, respectively on older CDs) you can find here.
• On the Car-HiHi page a proposal for ready-to-use satellites with data sheet (German) was added.
• At the end of the page Limitations of music recordings you'll find a table of contents of my evaluation CD together with some remarks what to care for
• You may find 4 new Music tips. Additionally 2 tips were revised according to comments from readers.

New since 03.03.2001 (Version of 11.10.2001):

• A new section Car-HiFi was added, where some basic problems of this special application are discussed.
• A new small WINDOWS-program to check the Consistency of TS-Parameters is available.
• You may find 4 new Music tips.
• Some details on the drawing of the DoppelWhopper system have been added (in German only).
• The order numbers and prices of the measurement microphone kit have been updated.
• The Link list was extended and updated.

• As I've never found the time to translate the more than 20 printed pages of the Tipps & Tricks zur Lautsprecherentwicklung (German only) and it had become too complex anyway, I've now created a short version called Tips for impatients that is available in English, too.
• On the Projects page you may now find photographs, measurement curves and order information for a measurement microphone with build-in pre-amplifier which may be connected directly to the line input of your soundcard. And the best is: the complete kit costs less than 20 €!
• On the Projects page there is a contribution to the provoking statements of Peter Krips' concerning horn loudspeakers ("Hörner - Voodoo - oder mehr?"). Measurement results of the "Buschhorn" could verify many of his theories!
• I have included photos of some of my former projects.
• On each page a link to the start page was established.

• Some news from the car-HiFi front line! The worked out concept for the VW Sharan was realized by a company called Car-HiFi-Exclusiv from Siegburg. The total system sounds already very sovereign and without stress even at high sound pressure levels. Again the first results including comments and interpretation (in German only!) are available in a simple interactive presentation:
  Download car-HiFi realization (German!, approx. 63 kB)
  The batch file RESULT1.BAT starts the presentation!
  Until now the integration of the front tweeters as well as the switchability of the rear system are not yet realized perfectly. This will be worked over soon. The final results will be presented when they are available!
• Those who own the satellite/subwoofer system QUADRAL SAT100/SAM46 (sounds really good for around $200) may find this simple, interactive presentations (German!, approx. 33 kB) helpful which gives some hints for the best adjustment of the many switches and controls.
  The batch file QUADRAL.BAT starts the presentation!
• Again SB_OCT was not 100% error free! As I had to do some additional changes to adapt SB_OCT to my new laptop the new version of SB_OCT (Revision: 30.07.2000) took a bit longer. Those who had problems to use the highest blocksize of 16k may now use the command line parameter -p to overcome the problem!
• A detailed project description of the DoppelWhopper system is available now (in German only). You'll find there some measurement results taken with SB_OCT, too.
• A new section Other loudspeaker homepages / DIY-projects (mainly German) has been created on my link page.
• The link list was checked and some new links added (e.g. room acoustics-calculator (German!)).
• You may find 4 new music tips.
• Thanks to a new laptop with new software some typing errors were found and corrected. If no change to the content of a page was made the date was kept!

• Unfortunately I've missed an error of the last revision of SB_OCT (31.03.2000) where the values evaluated during the mixer calibration process were not taken into account for the measurements. Moreover numerical problems could be observed with very small excitation levels. Furthermore the interpretation of reference spectra was changed in a way that not only identical but also higher octave resolutions are accepted. If a 1/24 octave reference spectrum is available this will also work for lower octave resolutions!

• SB_OCT was improved significantly (different sample rates, scope-mode) and offers now even higher value! Additionally a specially adapted Test-CD with pseudo-random noise, impulses and 1/3rd octave band swept sines (for subjective evaluation e.g. of room resonances) and an interactive file selector for DISP_OCT (display of result files) is available!
• I've performed an extensive Car-HiFi investigation for a VW Sharan. Goal of the investigation was to check in advance the potential benefit of a subwoofer, where it has to be placed and how to drive it. Furthermore it had to be checked, whether the original loudspeaker mounting locations are suitable for a high-end 2-way component system. The results of the measurements including comments and interpretation (in German only!) are available in a simple interactive presentation:
  Download car-HiFi pre-investigation (German!, approx. 65 kB)
  The batch file RESULT.BAT starts the presentation!
  Based on this pre-investigation an overall concept was evaluated. As soon as the system is build up and the frequency dividing networks are adapted the final results will be presented here!
• the link list was checked.

• some more pages are translated into English, only the very long (59kB) "Tips & tricks for speaker development" is available in German only.
• now this page is launched with remarks what has been changed since last revision.
• an error in BOXUTIL (inductor value for 1st order lowpass) was corrected (thanks to Andreas for the hint).
• the images on the Tips & Tricks and Download page are no longer displayed in separate new windows but are now integrated in the test (better for printing).
• now for SB_OCT an order form and a quick manual for impatient users is available (included in SB_OCT_E.ZIP).
• the link list was checked.