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Gallery Rick Kirpestein
Rick bought two of our new Digital Crossovers DCN23BOX
and this is his Dynaudio based DIY loudspeakers!

The feedback mail from Rick below starts with this sentence:

"Every evening I am enjoying the sound through the new DCN23 boxes..."

This is the "essence" of our philosophy - active amplification - to enhance the listening experience for our customers and not the technique for the sake of technique !

Rick Kirpestein:

History of my Audio Quest & Ground Sound review
In my case my "quest" started in 1996. I wanted to build an active Dynaudio 3 way system. Dynaudio because I had heard some Dynaudio's and had been impressed with the resolution of these loudspeakers.

I selected three drivers for various reasons:
* D28-2 (lucid high)
* D76AF (excellent "space", a disaster to filter)
* 24W100 (one of the best bass drivers to my opinion)

I made cabinets which even today still look sharp, inspired by the German Audiodata brand. Inner volume some 75ltrs and vented by Variovents. My friend -a professional church organ builder- designed the active filter for me. It wasn't a cheap solution but it sounded much better than anything I had heard before.


QNAP TS-219 3GB NAS server
Logitech Duet Squeezebox
Musical Fidelity 3-24 DAC (24bit/192 kHz upsampler)
Classe CP35 pre-amp
2* Ground Sound DCN23 Boxes
TAG McLaren 700:7R amplifier (7*100 watt)
CD-player * "looking for a Sony SCD-1"

I moved to New Zealand and decided I should buy a proper pre-amp. I listened to a Parasound pre-amp, then an Audiolab, then a Classe CP35. The whole exercise took some 12 weeks, no questions asked and a super service. Very laid back there in Hamilton New Zealand. The Classe was a vast improvement. In the mean time I had noticed that the speakers midrange wasn't finished. Too little detail.

I moved back to the Netherlands and wanted to improve my cd player. I therefore bought a Musical Fidelity 3 24 DAC. It was a great improvement, more detail and tonality. However, the speakers sound a little "nosy" in some passages. In the mean time I built a lot of DIY speakers which where sounding quite ok and had a noticeable better tonality. The "space" of my Dynaudio was never beaten however.

I tried many things due to the fact that I wasn't an expert a lot f things didn't work. I even bought a TACT RCS2.0 system. The system worked however needed to correct a whole lot! You will recognise digital clipping after one "treat" of it.... I therefore sold the TACT to somebody who had more trust than I did.

August 2009 I made a decision: Either I would sell the whole set-up or I would investigate whether I could improve the set. I went to Age van der Woud of Xanadu loudspeakers with my loudspeakers. I asked Age whether he could re-measure my set up. The midrange had a boost of 6dB and at 3.5kHz we measured a "crater" of -4dB! The original Phase allignment was perfect however. No wonder I always have heard my speakers needed improvement.

Age told me that the cabinets and the drivers absolutely shouldn't be abandoned. In his opinion the filter never had been finished. He advised me to look at digital filtering as a quick means to an improvement. He advised me some filters of Sitronik. I recalled articles on Ground Sound which I had read in Hobby Hifi a magazine which I always read back to back. On Ground Sound's website I found DCN23 prints which I rated of better quality than the Sitronik solution.

Not being an elecronics specialist I simply didn't know how to proceed since I didn't have any schematics on my amplifier plates. Robert offered to help me on a distance, I wasn't convinced I would pull this off. I asked whether there would be a plug & play version on the DCN23. Robert informed me he was in the process of creating these. I decided to wait on the boxes.

Somewhere in November the DCN23 Boxes where on sale. I immediatly bought them. Age van der Woud agreed to help me improve my set. It meant that I brought my set to him and he would measure and program the filters. Since Age is used to his own workshop this way an optimal result would be achieved. Two weeks ago I brought the set up on a saturday. It appeared that my amplifier plates should be regarded as antiques. I searched for a good amplifier on the internet and I bought a TAG McLaren 7 channel amp. Possibly similar to the current Audiolab 8000X 7.

Age started measuring at night and the next day the loudspeakers where "playing". It took one day of listening, measuring, optimising and then it was ok. I used to use lousy cables. Age advised much better interlinks which I purchased from him. So apart from the Ground Sound filtering, the amplifier improvement and the interlink improvement both where step changes as well. In order to get the proper tonality the experience of a professional loudspeaker manufacturer was used. Especially the D76 had proved to be difficult in the previous filter. With the tools available in the XOverWizard Software this was easily fixed.

Needless to say that when the whole system was set up at home again I had to re-check my ears. This was what I have been searching for, all these years. Superb and now in the higher price range class. But achieved through personal effort. More then I had imagined and it took also "an age". If I had known that the improvement with the Ground Sound filters would be so "dramatically positive" I would have taken action years ago.

So Robert, thx again for creating a digital filter that is superbly working!!

Best regards,
Rick Kirpestein © Ground Sound * Products of Denmark