My rebate cuts for the RS28A's are the perfect depth for the Peerless DA25's, but a smidge too large in diameter. Maybe .5 mm too large. Gonna go with them.
Take it apart and reassemble it , they have a tendency to get off center.
Roger that. I'll give it a try. Not that I don't like the Peerless DA25's. I've used them twice before and thought they sounded very good. I think Ben used them too in his first version of his Zingers. Very capable tweeter but the RS28's just fit so nice lol
I woudn't be too concerned about a 0.5mm gap, especially not enough to change my driver decisions. Paint the inside of the hole black and the gap will disappear, you won't notice from the couch
So I want to give a big shout out to my speaker brother Nick (Ugly Woofer)! I shouldn't have given up so easily on my pair of RS28A's tweeters. Shame on me
I took both tweeters apart and wiggled around and centered the voice coils as best I could and retightened the assembly. A quick DATs measurement was very promising. Both tweeters now had a distinct Fs impedance peak but they still didn't look identical. Just for S&G's I decided to switch voice coil/dome A and B with the other motor. Wow! They were a much better match, not perfect, but really close. For another S&G I decided to hook each one up to my amp and run OmniMic track 3 (fast sine sweep) at a pretty punishing loud dB level for 5 minutes.
I let them cool off for 30 minutes and then remeasured them with DATs. They now measure almost identically. Tweeter A has a Fs of 502 Hz, tweeter B is 537 Hz. Their peak impedance is almost the same. More importantly their impedance curve above 1k is exactly the same.
Thanks again Nick. Yeah, I have always liked how they sound in a competent project. I bought this pair as soon as it was apparent they were going to be NLA and PE had them on sale for $30!
Well the near field for the woofer looks really good. And the lower port looks so-so, but I don't know what to make of the upper port. That's some serious port resonance!
Hi Bill. I thought about that too. So I set the speaker in the center of the room and measure mid way between the ports about 24" away. Unfortunately there is a broad hump centered around 600 Hz. I will play around a bit with adding some thin foam inside the parimeter of the upper port to see if I can make it a bit lossy and reduce that resonance peak a bit. Otherwise I'm looking at buying a pair of DSA215PR to replace the upper ports with.
Comments
Baffles flush trimmed and rounded over. Ready to wire and mount drivers for testing:
Well they have 3 impedance peaks and look pretty close to each other...
Oh crap! One of my RS28A-4 has an issue
It shows almost no impedance peak and is noticably quieter during the sweep.
Plan B
My rebate cuts for the RS28A's are the perfect depth for the Peerless DA25's, but a smidge too large in diameter. Maybe .5 mm too large. Gonna go with them.
I have used o-rings to fill gaps before. Looks almost intentional.
Take it apart and reassemble it , they have a tendency to get off center.
Roger that. I'll give it a try. Not that I don't like the Peerless DA25's. I've used them twice before and thought they sounded very good. I think Ben used them too in his first version of his Zingers. Very capable tweeter but the RS28's just fit so nice lol
F3? Yes models very close to that.
I woudn't be too concerned about a 0.5mm gap, especially not enough to change my driver decisions. Paint the inside of the hole black and the gap will disappear, you won't notice from the couch
So I want to give a big shout out to my speaker brother Nick (Ugly Woofer)! I shouldn't have given up so easily on my pair of RS28A's tweeters. Shame on me
I took both tweeters apart and wiggled around and centered the voice coils as best I could and retightened the assembly. A quick DATs measurement was very promising. Both tweeters now had a distinct Fs impedance peak but they still didn't look identical. Just for S&G's I decided to switch voice coil/dome A and B with the other motor. Wow! They were a much better match, not perfect, but really close. For another S&G I decided to hook each one up to my amp and run OmniMic track 3 (fast sine sweep) at a pretty punishing loud dB level for 5 minutes.
I let them cool off for 30 minutes and then remeasured them with DATs. They now measure almost identically. Tweeter A has a Fs of 502 Hz, tweeter B is 537 Hz. Their peak impedance is almost the same. More importantly their impedance curve above 1k is exactly the same.
I'm glad it fixed them, they're great tweeters.
Thanks again Nick. Yeah, I have always liked how they sound in a competent project. I bought this pair as soon as it was apparent they were going to be NLA and PE had them on sale for $30!
What a steal...
InDIYana Event Website
Here are the woofer and tweeter measurements from 1 meter on listening axis:
That looks great Craig.
Yes I can.
My wife and kids will be at youth group tonight so I should be able to take NF port measurements and post them.
Maybe tomorrow.
All NF port(s) and driver measurements taken. Much easier for me to post them tomorrow morning from a different computer.
Well the near field for the woofer looks really good. And the lower port looks so-so, but I don't know what to make of the upper port. That's some serious port resonance!
So here are the three combined (measured at 1 Meter).
Yeah both of them have the 600Hz ugly. You'd think it should be octaves of 30, maybe the internal port has something to do with it?
That upper port could definitely use a resonance trap to it's benefit.
Try plugging the upper port and see what you get. Some drivers prefer it closed.
InDIYana Event Website
I've got a few things to try. All the way up to replacing the upper port with a passive radiator. It's only Sept and Indy 2024 is 6 or 7 months away
Do the ports end up out of phase in a DCR? It appears to me that the 600 Hz dip is cancelling out when the ports are combined...
Hi Bill. I thought about that too. So I set the speaker in the center of the room and measure mid way between the ports about 24" away. Unfortunately there is a broad hump centered around 600 Hz. I will play around a bit with adding some thin foam inside the parimeter of the upper port to see if I can make it a bit lossy and reduce that resonance peak a bit. Otherwise I'm looking at buying a pair of DSA215PR to replace the upper ports with.