Did you respond to my post above? If so I was probably unclear in what i meant. Even if you seal the back chamber, i think your front chamber wont lead to all sound waves from the big woofer coming out of your rectangular opening in phase. At low frequencies, yes, but then the woofer is omnidirectional even without the smaller opening.. Or is there something i misunderstand?
cookie, if I understand right he's only using these below 300hz. That leads back to PB's point 1 but at those low frequencies I don't see any improvement in the vertical.
Yes, the phase plug would be more useful if I was running these woofers higher.
Here's an illustration to demonstrate what I mean. In the illustration we see that the bottom edge of the fifteen inch woofer has a pathlength that's about 12.7cm different than the midrange drivers.
That means that it's going to be 180 degrees out of phase at 1,340hz.
Of course it's not as simple as drawing light rays; we also have to keep in mind that there's a path inside of the phase plug itself.
Fortunately, I got lucky. The frequency of the 15" woofer is smoother WITH the phase plug than without it. With the phase plug the TC Sounds woofer has a broad response that extends for two octaves, from 100hz to 400hz.
Without the phase plug, the F3 was the same, but the response at the upper end had some peaks and dips. The phase plug makes them go away.
An externally hosted image should be here but it was not working when we last tested it.
It occurred to me that something like the SPL Runt might be pretty easy to implement now that we have MiniDSP. In a passive Synergy horn it's a real p.i.t.a. to use large woofers, because you have to find a woofer that has the right Thiele Small parameters AND it needs to be physically small enough that you can put the midrange taps in the right location. Even in Monster Mirror I'm struggling with this, because it's hard to get the midranges close enough to the throat.
But DSP makes a lot of this easier, because you can delay the midranges.
So basically all you really need to worry about is the Thiele Small parameters, for the most part.
I'm thinking that's how VTC gets away with using 8" and 10" drivers also. (The manual indicates that DSP is required)
PB,
I think you have some competition from Bolexsbm from Korea.
http://www.diyaudio.com/forums/full-range/237948-speaker-kicks-butt-large-spaces-63.html#post4181957
I think you have some competition from Bolexsbm from Korea.
http://www.diyaudio.com/forums/full-range/237948-speaker-kicks-butt-large-spaces-63.html#post4181957
Last edited:
Worked pretty well. I'm building a new one. Check out the thread titled "Synergy Sound Bar"
- Status
- Not open for further replies.