I have found the Wallflower transparent enough to expose many cases of CDs recorded in the opposite absolute polarity of most of them. I used to stack them into two separate piles and just dig out of one pile each time I listened. Not the best way. It is very simple to insert a DPDT switch in the line to the speaker. Flip it one way and the lines continue to enter the speaker in the normal fashion. Flip it the other way and the lines cross over and reverse the polarity. Actually I've had a switch in my lines for years and would feel lost without it.
Figure 6 shows the way to wire up the switch. The switch is the same type as switch S1 in Figure 3, so just order two more of them for a pair of Wallflowers.

The positive input terminal of the crossover box is connected to a center terminal of the AP switch (site 1 on Fig. 6) The negative terminal of the crossover box is connected to the other center terminal of the AP switch (site 2 on Fig. 6)

Figure 6 -- Absolute Polarity Switch

<clik image for larger figure>

Connect wires to sites 3 and 4 of fig. 6. Attach them together at site 5, which is the input center terminal of switch S1 (this is on Fig 6 and also on fig. 3). If you are adding the AP switch to an existing completed crossover you will have to remove the existing wires at sites 5 and 8 on Fig. 3. The wires you remove will then go to sites 1 and 2 on Fig. 6 (the input wires to the AP switch.

I call the AP-switch-position that allows the signal to enter the crossover in the same polarity it left the amplifier, position A. I call the ~P switch position that reverses the polarity of the amplifier, position B_ That sounds a bit formal, but it's always nice to know which position has the straight wires.

I discovered the importance of Absolute Polarity about a decade ago when I reviewed a book on the Wood Effect (as this phenomenon is called) by Clark Johnsen. It has increased my pleasure immeasurably when listening to music.

It doesn't work equally well on all material. If you have a gimicky CD with a microphone for every instrument, or a lot of fake reverb, don't expect much. There are phase shifts all over the place on such a disc and natural sound just isn't in it. On the other hand a minimally miked CD with carefully placed microphones, done by someone who knows what he's doing can bring you a rich reward. It's the cheapest system improvement that often works that I know about.

On another note: A few weeks before I started to revise this article for Net presentation, I was thinking about George Augspurger's very interesting 3 part article in Speaker Builder Numbers 2,3 and 4 2000. I was especially thinking about what he said about reducing port area. Since it was so easily accomplished I tried it on a couple of my systems. The Wallflower was one of them. I cut the area in half by just simply gluing a particle board plate across the existing port.

I really expected to hear a somewhat constricted sound. I didn't. What I heard was as natural and transparent as what I heard before I reduced the port area.

In the past few weeks I've heard nothing that would make me consider going back to the larger port. I have incorporated the smaller port into the design of this article. (The original port was 5" square.) I'm sure it gives better loading to the driver at absolutely (that I can tell) no compromise to the performance. If I were a measurer (as most persons know I'm not) I wouldn't be surprised to find things a bit better in the low end. (If only I could say that about myself.) Have fun and enjoy.

[ Back to Projects | Contents | The Wallflower | Assembly | Parts | Epilog | Appendix ]