I have listened to parts of various albums now with dipole tweeters, mainly jazz as they are on the whole better recordings.
My past brushes with open baffle have been interesting but ultimately flawed and never really satisfying. That was with a mid bass though. I have never tried open baffle tweeters though, until now.
Well what can I say apart from I love it.
The sound is so open and airy with a sense of ease. Every album I have played has been good with no problems. Donald Byrd - Slow Drag, Places and Spaces, Street Lady, Stevie wonder - Songs in the key of life, The police - Synchronicity.
The last track on Slow Drag has some brush work and I have never heard anything like it. Some instruments appear outside the speakers now which has never happened before. It's bloody awesome
No draw backs I can hear. Listening to The Crusaders - Street Life now. The emotion in Randy Crawford's voice is at an all time high.
I now have a problem though. I don't like the look of the naked tweeters as much as when they were in a sphere. From the listening position they look good but not so much from the side. But I much prefer the sound with the dipole tweeters. Other variables have changed too like there is no longer a 15cm diameter sphere over the top of the cone. I don't sonically need the diffuser as the front firing tweeter fills in the top end.
I do worry about the re radiation from the mid bass off the tweeter but I can't hear anything that points at that being a problem. Same with the abrupt edge at the end of the rubber ring I have stuck on the front of the frame. I can't remember at what frequency it will start to diffract from a 95mm circle. I suppose it helps that the high pass filter is at 10KHz and by the time we reach the frequency with a wavelength greater than 95mm the driver's output is 18dB down.
The other thing that has changed is the tweeter is right above the mid bass' voice coil now. When it was mounted in the sphere it was above the surround so it has moved back about 7cm. Sounds good to me, it's hard to say if it has had an effect as other things have changed at the same time.
The goosenecks work really well. The 20cm ones are just the right length to get the tweeter right above the mid bass' voice coil. They are stiff but easy to bend where you want them and they stay in that position. There is bugger all weight on them which helps. It turns out they were made by QTX
Where have we heard that name before
I will have to have a think about ways to make the naked driver look better. The wires will be inside the gooseneck eventually so that's not going to be a problem. You can buy black magicians soft foam balls about 10cm diameter. If I hollowed one of them out to go on the back of the driver maybe ? Would that kill the dipole loveliness ? Or strangle the back wave too much ?