Matt's 505 Project

Matt is a long standing customer of ours having had his set of Acorns for
around 7 years, which can be found elsewhere on this website.

Matt is a long standing customer of ours having had his set of Acorns for around 7 years, which can be found elsewhere on this website.

Some time ago he purchased an early set of 505 panels to create a separate system in the library / study and has been very happy with the performance. However, he knew we had made some changes to the panels to enable a lower crossover point to make them easier to integrate with a dynamic bass driver, so he considered an upgrade.

A week or so ago he upgraded to the current version of the 505 panel, which has seen some improvements since its introduction around 6 years ago.

This is his latest construction.

Matt wanted to mount the 505 panels in front of a simple box to house the electronics. He intended to have a short gloss black plate of acrylic beneath the panel which would insert into the channel section that holds the edges of the panel together. This meant we had to supply a slightly longer edge channel to allow this to happen. The interface between the bottom of the panel and the acrylic is a black “H” section we use in our ESL IV and Acorn loudspeakers, this covers the edges of the acrylic and panel.

We duly supplied the 505’s with extended sides, the pics below are the result.

Matt’s Note

The enclosures were built from stacking 12mm ply layers, and the top layers are held in place with a magnet so that you can pull the lid off and access the PCB.  I stacked two panels slightly forward on the front face so that the mini panel could be mounted without the side clamp edges strips fouling the front.  

The spacer panel under the esl panel worked a treat in holding everything together and gives the whole unit a streamlined appearance.

The ply was finished with a ‘Black Japan’ stain to the top and bottom (underside), and then the whole thing finished in fine buffing oil so silky smooth.

Importantly, on the sound, the panels clearly excel in the bass department compared to my earlier ones - I was able to bring the small ripole crossover down from about 140Hz to about 90 Hz - I actually went back to using dsp just for the bass as I found the cheap and cheerful crossover I had before (ebay special) wasn’t cutting low enough and the sound was a bit muddied.  With the dsp, I used a fourth order filter (24 dB), and it has all come together very well, particularly when using vinyl playback.

Thanks heaps for your help in getting the mounting system for the panels sorted - everything went together perfectly!


The 505’s are not designed to cover bass frequencies so a dynamic driver has to be used to achieve full range reproduction.
Matt has used the Ripole type of bass system before so decided to make a smaller version of the standard Ripole using a pair of Peerless 8” drivers.

He decided to make this system a 2.1 type and has mounted a single Ripole on the floor, more or less centrally between them, not seen in this picture.

He is using a simple DSP for the bass crossover at 90Hz with a 24 dB slope.

Note from Rob: 90 Hz is probably a bit low for the 505 panel, I suspect this is only made possible if the Ripole has a slight lift in response at around 80 to 150 Hz.
Power Supply