Mine are 900 x 300, two of hinged, each side. I took apart a futon a few years ago and kept the stuffing. So there is wool (or cotton?) batting, then white fluffy cotton batting, then polyester wadding, then egg-crate acoustic foam to a total of 100mm. The walls behind the amps, and partly behind the speakers, have 60mm of 200kg/m3 rockwool anyway. We'll see how it goes, but it only cost me for the hinges and some rubber feet.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
I have close to 40 years experiece with Quads but that doesn't mean I know the answers.
Rear wave- In my experience if you have the space move the Quads 10' from any walls or corners. If you are not blessed with a baronial living room what seems to work is an absorbing panel behind the Quad (wool is best) but orient the rear panels so any reflection is directed to the other absorber. This seems to do the best at reducing reflections back through the speaker.
Dust cover- Years ago, for the Crosby Quads we sourced from DuPont about 10 miles of 1/2 micron (20 microinch) mylar for dustcovers. it worked really well BUT went up in smoke in the Paradise fire. It took 6 months to get it then and was not cheap. It was primarily used for capacitors. In any case thinner does seem to sound better. the stuff was a bitch to handle. Very fragile.
Power supply- raising the impedance does help. We used 100 MegOhm resistors where the HV connects to the panel. helps insure its charge operated which is the most linear.
Adding mass to the frame and adding the support in the center of the top makes a big difference. As does raising them off the floor.
More transparent metal grilles and fabric are also important.
Rear wave- In my experience if you have the space move the Quads 10' from any walls or corners. If you are not blessed with a baronial living room what seems to work is an absorbing panel behind the Quad (wool is best) but orient the rear panels so any reflection is directed to the other absorber. This seems to do the best at reducing reflections back through the speaker.
Dust cover- Years ago, for the Crosby Quads we sourced from DuPont about 10 miles of 1/2 micron (20 microinch) mylar for dustcovers. it worked really well BUT went up in smoke in the Paradise fire. It took 6 months to get it then and was not cheap. It was primarily used for capacitors. In any case thinner does seem to sound better. the stuff was a bitch to handle. Very fragile.
Power supply- raising the impedance does help. We used 100 MegOhm resistors where the HV connects to the panel. helps insure its charge operated which is the most linear.
Adding mass to the frame and adding the support in the center of the top makes a big difference. As does raising them off the floor.
More transparent metal grilles and fabric are also important.
Demian: thanks for that info. But of course that raises some more questions.
Are the 100 MegOhm resistors simply connected in-line at the bottom of the rear panel? Or one per panel (8 in total)? And are 0.4W adequate?
The 2805s have a rear strut and aly side panels. Is more needed than that? I already plan to make new curved top plates out of oak, so I can fix things to them without damaging the original gloss black ones. Super tweeters if I can try before buying, or even as somewhere to stick Christmas cards. WAF is somewhat important, that way I can get away with murder. 😀
Raising them will probably beyond murder though, unless I do it gradually, so the boss gets used to it. The previous speakers were taller but narrower.
New grilles: One Thing Audio have more open grilles for the 63s, but the 2805s have curved tops and bottoms, so I am thinking that if I can source some less restrictive aly mesh/perforated sheet, I will need to make new top and bottom parts, probably of oak again in order to incorporate the necessary grooves, etc. The angled aly sides should easy enough. Could the rear grilles be left as they are, though?
Does this make any sense?
Are the 100 MegOhm resistors simply connected in-line at the bottom of the rear panel? Or one per panel (8 in total)? And are 0.4W adequate?
The 2805s have a rear strut and aly side panels. Is more needed than that? I already plan to make new curved top plates out of oak, so I can fix things to them without damaging the original gloss black ones. Super tweeters if I can try before buying, or even as somewhere to stick Christmas cards. WAF is somewhat important, that way I can get away with murder. 😀
Raising them will probably beyond murder though, unless I do it gradually, so the boss gets used to it. The previous speakers were taller but narrower.
New grilles: One Thing Audio have more open grilles for the 63s, but the 2805s have curved tops and bottoms, so I am thinking that if I can source some less restrictive aly mesh/perforated sheet, I will need to make new top and bottom parts, probably of oak again in order to incorporate the necessary grooves, etc. The angled aly sides should easy enough. Could the rear grilles be left as they are, though?
Does this make any sense?
Just spoken to Akustikstoff who say they supply Quad with the grille cloth, trying to get the most HF transparent cloth in the colour I want. Slightly crossed wires I fear, but at least I know what I can get away with. Less HF losses would be good, but if I can make more open metal work behind the cloth it might do.
I think I ought to start another thread about getting the best out of these speakers, rather than keep this one going with general questions. It might get more views from other users.
I think I ought to start another thread about getting the best out of these speakers, rather than keep this one going with general questions. It might get more views from other users.
The center channel area that holds all the panels is what Demian is referring to.
It simply vibrates at its center way too much. You can watch and feel the movement
easily with it stripped down and playing. (Safely of course - High Voltage !)
I was able to build out with wood poplar blocks just enough to attach to the vertical side panel covers, but if I did it again I would replace the stock channel with a much thicker
aluminum piece. A replacement should be easy to find.
Where each panel stack and touch each other I used clear double sided tape used in store fixture glass assembly.
Very dense and it has a red peel off strip usually. Get rid of all the soft foam.
Clamp all panels top to bottom with this new DS tape between each panel and attach to new channel support.
First arrival times dont need to compete with bouncing rear waves and the need to absorb them will benefit imaging. I have a 23X27” room with 12’ cathedral ceiling peak and have them at least 10’ from the back wall.
Demian gives great advice here.
Regards
David
It simply vibrates at its center way too much. You can watch and feel the movement
easily with it stripped down and playing. (Safely of course - High Voltage !)
I was able to build out with wood poplar blocks just enough to attach to the vertical side panel covers, but if I did it again I would replace the stock channel with a much thicker
aluminum piece. A replacement should be easy to find.
Where each panel stack and touch each other I used clear double sided tape used in store fixture glass assembly.
Very dense and it has a red peel off strip usually. Get rid of all the soft foam.
Clamp all panels top to bottom with this new DS tape between each panel and attach to new channel support.
First arrival times dont need to compete with bouncing rear waves and the need to absorb them will benefit imaging. I have a 23X27” room with 12’ cathedral ceiling peak and have them at least 10’ from the back wall.
Demian gives great advice here.
Regards
David
I'm not sure I understand what the centre channel area is. Do you mean the top and bottom horizontal rails with foam, where the top and bottom panels sit? These are now braced along their length to stop flexing? Or do you mean the vertical side rails?
And each panel, where they touch each other, have no foam at all, they just screw to the side rails with 4 screws per panel. So they should be stuck together? Would they be removable for repair in that case? Have I understood this correctly?
And each panel, where they touch each other, have no foam at all, they just screw to the side rails with 4 screws per panel. So they should be stuck together? Would they be removable for repair in that case? Have I understood this correctly?