ATS4, built by Bertrand and Dominic, Canada
Copyright 2016 © Troels Gravesen

Hello Troels,
I hope you are doing well.  I wanted to give you a quick story on my friend’s and my brand new ATS-4s.  As you know, I have made your Ellam Flex 3W in the past.  We bought the cross-over kit and speaker drivers about 2 years ago but started construction only this summer.  Making 2 pairs of speakers does not take twice as much time as, for the actual construction, most of the work is to set up the cuts.  Then, cutting is just quick.  We spent the summer working on the construction to be able to finish them in early September to be able to send them for painting.  As these are your flagship speakers (and would be the best I would ever own), we wanted these to be as close to perfect as possible.  I used a CAD program, Fusion360, to model some parts that would go on the speakers.  I liberally inspired myself on the Alexia speakers from Wilson Audio for the parts.  These were machined from aluminum by a friend of ours and then anodized black to keep with the theme.  My friend was instrumental in putting together jigs to ensure repeatability of some design elements which made things so much easier (learned a lot from him).  I had a particular vision of what I wanted the tweeter box to look like and “enjoyed” myself putting that together.  I think I was pretty innovative in the way I made it all work.  Once construction was completed, we then put in the appropriate stuffing in place.  That took a while to ensure everything was done properly.  A quick note here to say that the kit could be a bit more generous with the stuffing as we did not have enough.  We then cut the fronts to size and shaped them and glued them on.  Final sanding and these were ready for paint.  The paint took way longer than anticipated due to issues on the painter’s side but we finally received them back about 2 weeks ago.  The final touches took 16 hours to do (putting wires in place, putting all the aluminum parts and drivers in place, etc.). So overall, the construction from start to finish, excluding paint, took about 300 hours.  They are currently being broken in with various types of music.  The first album that played on my pair to hear them was Count Basie’s 88 Basie Street album.  Right from the start, I heard that these were spectacular.  I love my Ellams but the ATS-4 is beyond those.
Thank you again for taking the time to answer my questions and especially for your amazing designs.  There are now an additional pair of ATS-4 in Montreal, QC and in Scotch Pains, NJ. We both love them very much.
If you and your readers want more construction pictures as well as other pictures, please go here:  It is in French but the pictures are multilingual… 


Hi Troels,

Firstly I wanted to thank you very much for sharing the ATS-4 speaker design with the DIY community! Bertrand and I had a blast building them and I can honestly say they are the best I've owned and probably heard!
Some of my friends who listened to them were totally impressed by the imaging, realism and details they produce. I'm currently driving them with my friend's amplifier design USSA 5, a two stage Class A Current Feedback Amplifier. The duo is quite exquisite!
Thanks again for everything!