I’m looking at mating my center channel design (51/4” Revelator / Hiquphon tweeter) with a woofer to make a pair of mains. I figured I could cross over around 200 Hz. I wanted to try the ScanSpeak 9” 23W / 4557T00. The Madisound website suggests pairing it with its passive radiator the ScanSpeak 23W / 0-00-00 in a 1 cf box.
I modeled it in unibox and got an F3 of 26.5hz with 140 watts / walls covered / no leaks. That looked pretty good but I got cone excursion problems at 35 Hz. I played with the mass of the pr and if I took it down to 200gm (half the spec ) it looked pretty good, but I have no idea how much weight you can remove, if any, from that pr.
I then tried reducing the volume and at 20L it looked pretty good (F3 of 28.3hz), but when I started sizing the box, getting two 9” speakers to fit seemed pretty sporty. I wanted them to both point forward, I definitely don’t want one in the side wall. If I put the pr in the back I’m afraid the box might be too shallow.
I don’t have permission from my Chancellor of the Exchequer to start a new project at all, let alone an expensive one! So right know I just want to learn the process.
So, any comments on those two designs?
Then I have some general unibox questions-
First and foremost – am I even running unibox correctly?
What does the impedance curve tell me about the design?
What do the Step Response and Power Amplifier peak voltage tell me?
Lastly - looking at the spl curve where all contributors are plotted I was surprised to see the excursion drop off rapidly at the low frequencies and more surprised that the contribution of the pr added to make the total spl respectable. I wouldn't have thought the pr would add, since I assumed it was out of phase.
I’ve pasted the T/S parameters into an attached text doc.
I will certainly appreciate any advice,
JohnZ
I modeled it in unibox and got an F3 of 26.5hz with 140 watts / walls covered / no leaks. That looked pretty good but I got cone excursion problems at 35 Hz. I played with the mass of the pr and if I took it down to 200gm (half the spec ) it looked pretty good, but I have no idea how much weight you can remove, if any, from that pr.
I then tried reducing the volume and at 20L it looked pretty good (F3 of 28.3hz), but when I started sizing the box, getting two 9” speakers to fit seemed pretty sporty. I wanted them to both point forward, I definitely don’t want one in the side wall. If I put the pr in the back I’m afraid the box might be too shallow.
I don’t have permission from my Chancellor of the Exchequer to start a new project at all, let alone an expensive one! So right know I just want to learn the process.
So, any comments on those two designs?
Then I have some general unibox questions-
First and foremost – am I even running unibox correctly?
What does the impedance curve tell me about the design?
What do the Step Response and Power Amplifier peak voltage tell me?
Lastly - looking at the spl curve where all contributors are plotted I was surprised to see the excursion drop off rapidly at the low frequencies and more surprised that the contribution of the pr added to make the total spl respectable. I wouldn't have thought the pr would add, since I assumed it was out of phase.
I’ve pasted the T/S parameters into an attached text doc.
I will certainly appreciate any advice,
JohnZ