I've been curious about the impact of lateral (side-wall) reflections from speakers. Some people treat them, others don't. I was pretty sure I preferred them. I had a hunch that the ipsilateral (same side) reflections were beneficial for adding breadth to the soundstage. After seeing the measurements of the C-note on this site, I developed a plan to use the same waveguide tweeter in a speaker that would have variable directivity.
In order to accomplish this, I would put a tweeter on the front, but have a second tweeter on the side facing away from the listener. The side tweeter would be optional, and could be turned on, or off. The front and side would also both have mid-woofers. I have used the RS125-4 in previous designs and liked it, and had several laying around. They don't need a lot of volume, so putting two in a small bookshelf was possible. I ported it to get some extra bass out of them, but they still only reach down to 60 Hz or so.
I attempted to keep the front and side drivers as close as possible, by placing them close to the corner. This required me to flip the placement of the side drivers, in order to make room for the woofer magnets. That's why the front woofer is on the bottom, but the side woofer is on the top.
I used a bi-amp speaker terminal. The bottom terminal is wired to the front drivers and the side woofer. The side woofer has to be on all the time, as it basically fills in the baffle step. At low frequencies you're listening to both woofers, and you can't just turn one off without changing the direct sound spectrum. The top terminal is wired the the side tweeter, allowing me to turn it on or off at will. The side tweeter doesn't impact the direct sound much at all, particularly on the design axis, which is about 15 or 20 degrees inside of the line normal to the face of the speaker.
Of course, this is a flawed design that I put together just to get a hint of what the impact would be, and see if there was promise to the idea. The crossover is at about 2500 Hz. That means the side woofer is "splashing" the ipsilateral side wall with frequencies up to 2500 Hz all the time. That's most musical content. I don't find the tweeter to sound particularly high end, but I needed 4 of them for this experiment, so the price was right. The bass extension is limited.
Having said that, it was very interesting to be able to turn that side tweeter on and off at will. I found that I did prefer it on. I also found that the speaker sounded much better than it should given all the flaws and compromises. On certain songs, the effect of blasting that outside wall with energy is pretty awesome. It really fills the room, but in a way that still maintains a lot of coherence and detail if compared to something like the bose 901.
So now I've been contemplating what an idealized version of this speaker concept would look like. I'll post about that, and some measurements in a follow-up.
In order to accomplish this, I would put a tweeter on the front, but have a second tweeter on the side facing away from the listener. The side tweeter would be optional, and could be turned on, or off. The front and side would also both have mid-woofers. I have used the RS125-4 in previous designs and liked it, and had several laying around. They don't need a lot of volume, so putting two in a small bookshelf was possible. I ported it to get some extra bass out of them, but they still only reach down to 60 Hz or so.
I attempted to keep the front and side drivers as close as possible, by placing them close to the corner. This required me to flip the placement of the side drivers, in order to make room for the woofer magnets. That's why the front woofer is on the bottom, but the side woofer is on the top.
I used a bi-amp speaker terminal. The bottom terminal is wired to the front drivers and the side woofer. The side woofer has to be on all the time, as it basically fills in the baffle step. At low frequencies you're listening to both woofers, and you can't just turn one off without changing the direct sound spectrum. The top terminal is wired the the side tweeter, allowing me to turn it on or off at will. The side tweeter doesn't impact the direct sound much at all, particularly on the design axis, which is about 15 or 20 degrees inside of the line normal to the face of the speaker.
Of course, this is a flawed design that I put together just to get a hint of what the impact would be, and see if there was promise to the idea. The crossover is at about 2500 Hz. That means the side woofer is "splashing" the ipsilateral side wall with frequencies up to 2500 Hz all the time. That's most musical content. I don't find the tweeter to sound particularly high end, but I needed 4 of them for this experiment, so the price was right. The bass extension is limited.
Having said that, it was very interesting to be able to turn that side tweeter on and off at will. I found that I did prefer it on. I also found that the speaker sounded much better than it should given all the flaws and compromises. On certain songs, the effect of blasting that outside wall with energy is pretty awesome. It really fills the room, but in a way that still maintains a lot of coherence and detail if compared to something like the bose 901.
So now I've been contemplating what an idealized version of this speaker concept would look like. I'll post about that, and some measurements in a follow-up.