It's sub zero in Denver today, and I am no way going outside for anything. Even the dogs don't linger outside. They go out, do their business, and run right back in. This is the perfect day to experiment and publish more findings on my copper room treatments.
I've actually not stopped experimenting, and learning about copper and it's effects on the room. Much like the Frank Tchang's and Synergistic Researches acoustic resonators, copper seems to have an effect on the way one's speakers work in the room. The simplest way I can put it is this: Even with conventional acoustic treatments placed very carefully, the audio system seems to fight with the room. One can literally sense this as congestion, veiling and pressure. You can "hear" the room that the system is in. One can make the speakers disappear with judicious placement, but making the room disappear is another matter altogether.
With somewhat careful placement of differing sizes, gauges and configurations of copper, the room seems to depressurize and let go of the music at all frequencies. You can hear it and feel when you listen to recordings with a good sense of space (artificial or real). One is more convincingly transported to the venue, right in the middle of the stage at times. Clarity is improved without increasing brightness, decays go on forever, dynamics improve, extremely low level detail emerges, and all is done with a naturalness that appears to the listener as a more "real" sound.
What Have I learned?So what has changed since my last posting? Quite a bit has changed, and I have learned quite a bit as well. Let me cover what I have learned first.
There is no one size fits all
As much as I tried to simplify implementation, there is just no one size wire/rod, one length or concrete placement that works for everything. Here are the variations I have worked with:
- Copper rod: Size (awg) matters. Don't even mess with wire thinner than 6 awg. Wire thinner than that tends to over emphasize high frequencies, and gets ugly pretty quickly. The thicker the wire/rod, the lower the frequencies it works on. I have used up to 1/2" thick copper rod with wonderful results, and have larger diameter on the way. I have heard positive effects as low as 250hz with the larger rods. 2 18" segments do wonders for midbass/lower midrange issues in a room.
|1/2" copper rod in a cedar block. Placed to the side and |
behind the plane of the speakers. These are VERY
- Copper Sheet: I hung 2 - 1/16" thick x 4" wide x 24" long pieces on the wall behind my speakers, and about 2 feet apart. It helped focus the center image, and created an expansive soundstage across the entire back wall. I have a feeling they might work well on side walls too. I will be experimenting with that in the future.
- Copper cups: The Sertodo Copper cups, specifically the shot glass, and the 12 oz cup, work well. The shot glasses are the ambiance makers. Good at ear/tweeter level and in corners, or first reflection points. The larger cup I tend to put centered on the wall behind my speakers, but can go out in the room as well.
- Letting it ring vs. damping: I use a combination, but can tell you that when you let the copper ring, as in hang or stand a copper rod up so that most of it is not touching anything, you increase the chances of accentuating certain frequencies and getting narrower coverage of a room. Meaning you can only have so much copper freestanding and free-resonating before it gets out of balance sonically. That may mean you have more spotlit areas of your room, rather than a diffuse coverage. A little goes a long way.
Where We Are At Right Now
I titled this section "Where We Are At Right Now" because this is an ongoing journey. It was a good stopping point today because I am getting better sound than I was with the freestanding copper rods. I only use the large 1/2" copper rods now. I found that using smaller sections of copper rod, and attaching them to the walls and ceiling made significant improvements over copper rods placed about the room, plus it didn't take up floor space.
Random Placement & The Rear Wall
It started when I removed all the copper in the room, and began randomly placing 6" sections of copper over each wall in the listening room. After listening for awhile and determining it was worth pursuing, I started removing pieces of copper to determine which ones were more effectively placed. I found that the upper left & right quadrants of the walls behind the speakers benefitted most from this. I also found after further experimentation that I could use even shorter segments of copper.
|The right corner behind the speakers. Note the|
sunburst patter of copper on the wall directly
behind the speakers. Note also the copper rod
sitting atop a Stein Harmonizer.
This made the soundstage clearer, and with more width and depth behind the speakers. The center image focus was still in tact, as were instruments placed to the left and right of the soundstage. Detail improved greatly as well. Height is a factor in placing these small bits of copper. Placed at tweeter height or above seems to enhance the soundstage, placing them at woofer height seemed to warm up the sound, but narrow the soundstage. The takeaway: Height and amount of copper are important. If the sound starts getting bright or hollow sounding, back off the amount of copper placed at tweeter/ear level and higher. To warm things up, a few pieces of copper placed along the side walls at woofer height can add warmth and more midrange richness too.
I then took to the ceiling. In my listening room there is a drop in the ceiling of about 1 foot where the system sits. It drops from 8 to 7 feet right over my listening area, and I can hear it affecting the sound, particularly the image height.
|Note the pieces of copper placed on the low section of my ceiling. This is the |
area where the system and speakers reside. The 1" pieces of .1875" copper rod
cover this entire area of the ceiling.
To attack this issue I staggered 1" pieces of .1875" OFC copper rod and secured them to the ceiling with Loctite Fun-Tak (the hardware store version of Blu-Tak). I covered the entire ceiling in my experiment, and that is the way it remains for now. It definitely helped to restore image height, but also added more depth and detail to the sound. While the sound was now filling the space, with the speakers and the room "disappearing", the image stopped about where my listening position was. It makes sense because my listening chair sits about 4 feet outside of the "low ceiling" zone, and there was no copper placed to the sides or behind me yet.
The Ceiling, Part 2
Taking lessons from what I learned on the low ceiling, and the wall behind the speakers, I decided to try using the "sunburst" pattern of copper pieces that I used so successfully on the wall behind the speakers on areas of the higher ceiling. I placed three sunbursts on the ceiling behind my listening position. One to the left, one centered behind me, and one off to the right.
|Not The "sunburst" of copper pieces on the ceiling.|
After placing the sunbursts on the ceiling, Image height was further enhanced, as was the "wrap around" effect of ambience. I was immersed in sound, and it was good.
Where Will This Go?
My next experiments will go to heavier copper rod, more copper sheet, and perhaps even to copper plate. From what I have learned recently, I think more mass and a shape with more surface area may have a greater effect. I think a lot of magic is yet to be discovered. Stay tuned for more...