Sometimes in the world of acoustics, amazing discoveries are made by accident. It is only afterward that the science is unraveled to explain the unexpected effect that everyone just witnessed. This story is about one of those occasions…
HiFi Gear Makers Want Theirs to Sound..Simply the Best
At HiFi shows, manufacturers demo their products. It is very educational to audition room setup after room setup. One room with TubeTraps along the front wall has imaging floating in the air outside the room (see last week’s ATOW!). Another room with curtains drawn over plain flat sound panels has an image sitting on top of the speakers.
A Bold and Reckless Adjustment
One time the center TubeTrap was moved several feet forward to get to an electrical plug while the music was playing. From the perspective of the listener’s position, the image JUMPED forward!
Later we experimented with this strange effect.
Don’t Rush the Good Things
As you experiment with this effect yourself, keep a few things in mind:
make a small adjustment, and listen
listen to tracks you know well
get rid of random clutter between your speakers
keep your eyes mostly open, but out of focus…think 3D art
Here are a few of the unique reasons a TubeTrap is the best tool for this task:
no tonal coloration
all reflections are diffuse
all reflections are phase-coherent
free-standing with no hardware
Back Where You Started
As the 16″ diameter center trap was inched forward, the image slid forward (1). This continued…until the image seemed to fade from view (2). When we slid the TubeTrap back a bit, the image brightened up again but also moved backward. We concluded that the center image dims out when the TubeTrap has moved so far forward that the speakers no longer illuminate the reflector.
A Change is Gonna Come
To overcome this limitation, we built a special “forward image” TubeTrap with slightly smaller reflectors on each side. As we slid the special TubeTrap further forward, the image stayed bright and continued to move forward. With the TubeTrap half way between the speaker/listener, the image was HUGE and right in front of us.
It was in our face.
Something Beautiful Remains
What about Ms Turner, you ask? She’ll join the story next week in Part II, as the full capabilities of the “forward image” TubeTrap are tested and realized.