ATS4, built by Frank, The Netherlands
Copyright 2014 © Troels Gravesen


Dear Troels,
I have finished my ATS4 last week. I really enjoy them. In my attachment I have included some feedback and pictures of my build to contribute to your great website.
Many, many thanks for sharing this and your aid on my questions.
Kind Regards,
Frank, The Netherlands


First of all I wish to give my sincere gratitude for posting such high-end speaker designs.
This was my second build, the first being a scan-speak reference plus design using pre-cut panels:
I have sacrificed the adjustable tilt angle on mid/high to allow for an IMHO more pleasing tight design (they are in my ‘family’ living room). The phase-centers of the mid/high correspond with a 3 deg tilt angle for both mid/high in the original design. In my view fine with my listening position being 4 to 5 meters. I once replaced my Teflon internal speaker cables with Kimber 8TC and noticed a significant improvement, thus given the large length of the internal cables, I bought some second hand Siltech FT12 G3 for mid/high with twin lead for upper bass. I used the Jantzen copper kit-cable for lower bass which is good enough. I don’t use biwire, given a fixed budget, I think single wire gives best cost/performance ratio. For the mid I used Jantzen silver caps only. For the high I switched to Mundurf Silver/Gold/Oil capacitors and M-resist Supreme resistors following the experiences of Tony Gee:
The mid/high crossover is a closed compartment to make the design more appealing. The resistors to tune the tweeter level are placed at the base of the speaker. I prefer the 1 Ohm setting so far.
My impression of the sound in just one word: ‘Incredible’. They are in every way exceeding my expectations given my already nice scan speak reference plus. The sound is clear, transparent, fast with incredible dynamics and natural sound. I can listen for hours without any fatigue. The soundstage is very very deep and wide, with very clear positioning of the instruments and voices, I can see deep in the recording. Female voices are breath-taking. The instruments in classical music sound very real (my wife who plays cello highly agrees) and can be clearly identified in a big orchestra. The upper bas with closed cabinet really gives the fast punch I was hoping for. The lower bass gives plenty of lows. The reserve of my 60W class A Luxman M800a gives enough power to make the cones swing even at thunderous levels. To make a comparison; a friend of mine owns B&W 802 and dcs/Krell set, which sound I’m familiar with by now. He hasn’t heard them yet, but I’m pretty sure he will go home wining and wondering. I have them running for one week now, I don’t know about burn in time, but these are my experiences so far.
Once more, many thanks for this great design; these will give me many years of joy.