TL:DR You have to follow the build instructions. Really.
My 10 year old Pi 2 Towers were put together by a very talented carpenter who had never built a speaker in his life.
They were in my dad's house near a wall and a tall entertainment center so they had boundary reinforcement on two sides and they sounded OK but nothing like Wayne's did at the 2007 Lone Star Audio Show. My towers never quite sounded right.
That was a time when I was working insane hours so the Pi's never got much attention and as life got busier they just sat there unused.
Fast forward about 10 years and the towers got hooked up for a listen in my house ... and it wasn't good. They were lacking bass and thin through the midrange. In my house they weren't even OK sounding.
Moved 'em closer to the wall, moved 'em away from the wall, tried different electronics but it didn't help. A 2A3 amp went into the system and things got a whole lot better up top but the bass was still way too thin. Was toying with hooking up a sub and it just rubbed me the wrong way because 2 Pi Towers don't need subs ... that's why they are towers. If you build them as smaller monitor boxes they may need subs but bass should be fine when built as towers.
When they were at my dad's place I dampened the woofer baskets in an attempt to make them sound better. So I took the woofers out to see if any of the damping material I'd put on the woofer frames had fallen off the frames and was laying on the cones. Nope. Wiring was all correct, too. Nothing out of phase or reversed. Nothing out of the ordinary.
Then I started to feel around the box and started removing stuffing. The towers have insulation along several sides and on top of the two braces built to strengthen the cabinets. Low and behold it turns out the insulation on both of the braces had adhesive backing on it. Gary, who had never built a speaker before in his life, had stuck the backing over the braces with the adhesive in place effectively sealing shut the hole in both braces.
The seal effectively turned the 2 Pi Towers into something smaller than the 2 Pi monitors.
Removing the seal on both of the braces fixed 'em. 100 hours of white noise loosened them up considerably and they now most definitely have bass.
So after 10 years the 2 Pi Towers finally sound like they are supposed to sound. I'm tickled.
Wayne Parham Messages: 18785 Registered: January 2001
Illuminati (33rd Degree)
Barry, that's one of the best stories I've heard. After all these years doing email, phone and forum support, this one is one of the best.
I probably should make that more clear in the instructions, just because of this possibility. There have been plenty that have asked about the paper backing, but usually they're wondering about the sheets that are attached to the panels. In that case, the paper wouldn't hurt performance as much. It just might vibrate, and it isn't necessary. But in your case - the sheets spanning the cross-section - it's much more important that the paper be removed, for exactly the reason you've described.
Good catch finding the problem. Big time sorry it persisted so long. Makes for a funny story though!
The speakers still have the paper backing holding the insulation to the sides and top. It may get fixed in a while when there is time to pull all the insulation out, remove the paper backing and then glue the insulation back in properly.
Wayne Parham Messages: 18785 Registered: January 2001
Illuminati (33rd Degree)
It's not a problem unless it's a problem. Pretty Zen, huh Barry?!!
But seriously, the reason I've always removed the paper backing is simply a matter that it isn't needed. It can make a "crinkly sound" if it vibrates against one of the cabinet panels. It just isn't needed and I don't want it to buzz. But honestly, at volume levels that might get that stuff buzzing, the music content is a ton louder than the sound the paper might make. So no, I wouldn't spend a day pulling it all out to remove the paper backing.
Now the sheets spanning the cross-section are a different story.
You guys are funny! I really enjoyed the story about your speakers. I know just how you feel, once you discovered the problem. I hope you enjoy those speakers much more and have a wonderful day, both of you.