Welcome to my speaker pages. If you are interested in do-it-yourself loudspeakers, I hope that you'll look further.

I am an experimenter more than anything. I like to find out what makes something work (or not work, as the case may be). This has extended to speakers. I am at the point of doing design, from measurements to construction to final tweaking, but I still like to go back to taking something apart to see how it works. You'll find a bit of that here as it's interesting to open up a driver, usually tweeter, to study its construction and see if any DIY improvements are possible. This is quite often the case for tweeters. Larger drivers can at times also be improved, though with different methods. There is information on both of these topics in some of the pages.

Below you will find a list of sections inside. Each one is on a specific topic related to speakers, not in any particularly logical order, though grouped to some degree.

I started this site as part of a discussion on the Madisound Discussion board back around 2000. It just kept growing as I found new topics that were of interest to me. There will be topics to add or change over time, so I will update it occasionally.

Maybe one of the more useful pages is a web-based version of an article of mine published in Speaker Builder magazine (ONE:2000) included. It describes a method for determining relative acoustic offset for drivers when mounted on a baffle.

The Speaker Builder article covers one aspect of CAD design that must be properly handled if direct measurements are not used. That is, if the drivers are modeled and the minimum-phase (Hilbert-generated phase) of that model is used instead of the actual phase response.

The diffraction section shows the predicted and measured impact of baffle edge diffraction on the driver raw response as well as an extensive set of measurements of baffles with felt applied for diffraction reduction.

You may find a couple of pages on CAD software to be of interest. One deals with phase error due to an inaccurate CAD model. An example using CALSOD is extensively documented. A second one deals with the Hilbert-Bode transform and the effects which can occur when the CAD model does not have enough range, as when the high end rolloff of a tweeter is too high for the measurent system.

One of my early forays was Tweeter Tweaks. This section shows all details of adding wool to the pole piece vent, but not just any wool. I found, quite by accident, a product which is very useful for tweeters. It is used to stuff the pole piece vent and has absolutely no negative effects. I wholeheartedly recommend it for tweeters for which access to the pole piece vent is possible. Some tweeters either prevent access and/or they already have a good filler from the manufacturer. Examples of the latter are the Vifa XT-25 and the Scan-Speak tweeters (probably all of them). I also have a section that shows results of the testing of changing rear-chambers.

The models section shows a couple of the electrical and acoustic models used to represent a driver and/or system. It is one frequently used in CAD software.

The raw measurements pages are now for those taken on what I call my "quasi-IEC" baffle. Raw measurement text files either exported from LAUD v3.0 or CALSOD (with Hilbert phase using CALSOD) may be downloaded by anyone interested. Be aware, though, that they will only be quasi-anechoic (no baffle effects), so you won't get what these show. You'll have to post-process them for baffle diffraction. Tweeters will have significant baffle effects. Woofers and midranges will have baffle step loss. These files must be considered as useful more for some testing and learning than for any final designs. The files can be imported into the tools at the FRD Consortium to get approximations. Some users have taken it the extent of designing from scratch using this method, but it takes some experience to get really good results. It's always best to use actual measurements if possible.