I am working on a 4 way open baffle and I built a prototype using a hat stand (see attached picture). Because the subwoofer was too heavy to be suspended, I had the idea to make it similar to a rocking chair.
I know it is funny but look at the attached measurements (0, 30 and 60 degrees). I am sure the final system will be better. For now I used an old 6 way amplifier connected directly to the sound card from the motherboard of a computer and I spent about one hour in JRiver and HOLMimpulse to set the 4 way active crossovers and correct the response. The final system will use 4 Hypex NC400 and a Hypex DLCP.
Thank you StigErik for sharing your work and for inspiring me to go this way ( http://www.diyaudio.com/forums/multi-way/142015-my-open-baffle-dipole-beyma-tpl-150-a.html ).
What I have learned? First is that the best way to fight vibration is to allow it. I realized that I don't care if the baffle and the speakers vibrate but what I really want is not to hear this vibration. So I need to be sure that I don't transmit vibration from one driver to the other to hear about Doppler. And I also need to have all that is moving to vibrating in the same way as the driver membrane is. Suspending the drivers works and I got those.
For the subwoofer making it as a rocking chair is almost the same as suspending it. The resonance frequency is very low and the energy from the drivers is not stored.
Also I think is a good idea to use a hat stand and not a frame. The back on axis response is probably affected but the 90 degrees response may be better. I don't really care about all the polar in the back because I am listening from the front, but I care about how the sound from the back comes to the front.
I would recommend also the rear firing tweeter to anyone. I have no measurements to prove it but I listened and if you like dipole sound, go for it.
The drivers are all ScanSpeak (32W/4878T00, 18WU/4741T00, 12MU/4731T00, 2 x D3004/664000).
I know it is funny but look at the attached measurements (0, 30 and 60 degrees). I am sure the final system will be better. For now I used an old 6 way amplifier connected directly to the sound card from the motherboard of a computer and I spent about one hour in JRiver and HOLMimpulse to set the 4 way active crossovers and correct the response. The final system will use 4 Hypex NC400 and a Hypex DLCP.
Thank you StigErik for sharing your work and for inspiring me to go this way ( http://www.diyaudio.com/forums/multi-way/142015-my-open-baffle-dipole-beyma-tpl-150-a.html ).
What I have learned? First is that the best way to fight vibration is to allow it. I realized that I don't care if the baffle and the speakers vibrate but what I really want is not to hear this vibration. So I need to be sure that I don't transmit vibration from one driver to the other to hear about Doppler. And I also need to have all that is moving to vibrating in the same way as the driver membrane is. Suspending the drivers works and I got those.
For the subwoofer making it as a rocking chair is almost the same as suspending it. The resonance frequency is very low and the energy from the drivers is not stored.
Also I think is a good idea to use a hat stand and not a frame. The back on axis response is probably affected but the 90 degrees response may be better. I don't really care about all the polar in the back because I am listening from the front, but I care about how the sound from the back comes to the front.
I would recommend also the rear firing tweeter to anyone. I have no measurements to prove it but I listened and if you like dipole sound, go for it.
The drivers are all ScanSpeak (32W/4878T00, 18WU/4741T00, 12MU/4731T00, 2 x D3004/664000).
