I found some masking plugs at work that fit in the ports nice and tight. So that is "temporarily" taken care of. I installed the PR's, port plugs, and drivers. After a few trial and error efforts I have the PR's tuned exactly the same as the ports were (measured impedance curves with DATs). I was expecting that I would have to add more mass to the PR's. It turned out that I had to remove one washer (about 8 grams) and add some polyfill to get the impedance curves to overlay exactly. However, there is now a very small 4th impedance peak at 10 Hz. The peak is only 9 ohms and it is so low in frequency I'm not worried about it. Strange however... no enclosure dimension of this project could ever contribute to a resonance that low. Has anyone else seen something like this with PR's?
I've worked up a crossover design for this project and I am very pleased with how they sound. LR2 at 2kHz. Very smooth on and off axis response. These will be demo'd in Iowa in less than 2 weeks.
@PWRRYD said:
I've worked up a crossover design for this project and I am very pleased with how they sound. LR2 at 2kHz. Very smooth on and off axis response. These will be demo'd in Iowa in less than 2 weeks.
While the crossovers are installed interally, their design is definitely not set in stone. I'm hoping for some feedback this weekend. Anyone who is there and hears these please give me your opinions. Good or bad. I don't get personally hurt by negative feedback. If we all just circle jerked each other none of us would get any better at this hobby.
Comments
I found some masking plugs at work that fit in the ports nice and tight. So that is "temporarily" taken care of. I installed the PR's, port plugs, and drivers. After a few trial and error efforts I have the PR's tuned exactly the same as the ports were (measured impedance curves with DATs). I was expecting that I would have to add more mass to the PR's. It turned out that I had to remove one washer (about 8 grams) and add some polyfill to get the impedance curves to overlay exactly. However, there is now a very small 4th impedance peak at 10 Hz. The peak is only 9 ohms and it is so low in frequency I'm not worried about it. Strange however... no enclosure dimension of this project could ever contribute to a resonance that low. Has anyone else seen something like this with PR's?
Does your room have any walls about 30 feet apart? If so, the larger area of the PR could be more sensitive to room nodes.
That is close to half of the Fs of the PR with that amount added mass. Possibly a higher order harmonic in the the box slightly lining up with the PR?
I've worked up a crossover design for this project and I am very pleased with how they sound. LR2 at 2kHz. Very smooth on and off axis response. These will be demo'd in Iowa in less than 2 weeks.
Sounds like a winner!
While the crossovers are installed interally, their design is definitely not set in stone. I'm hoping for some feedback this weekend. Anyone who is there and hears these please give me your opinions. Good or bad. I don't get personally hurt by negative feedback. If we all just circle jerked each other none of us would get any better at this hobby.