For the most part, no. The bass range balances it out spectrally, and this is a bit of a smile curve. Mind you now, the measurement was taken at 10" above the tweeter axis, as I'm targeting an increasing lobe direction. Lower than that, and the mids will fill in a bit. It's not as bad as you think. Not all measurements are the same. It depends on application. I am not a downward-tilt fan. I prefer flat, and you have about a -2 to -3dB decline there.
As to the peaky bass, I ended up with 4 layers of batting the length of the main cavity to get it right. Any 'stuffing' killed the bass and made them really bright.
I've only had them together fiddling for a couple weeks. It might take a bit longer to make up my mind. Really though- most of what I've played have not been sssibilant or shouty. These tweeters are REALLY clean.
If that's what you like to listen to, don't let me change your mind, it's your speaker after all. Based on my own experience I would expect that to be rather treble forward is all.
A few other people heard them yesterday, and no one felt they were bright. I really don't think the measurements I've shown are indicative of everything that is going on.
I have done a bunch of listening over the last few weeks, and there is no need to add the LR filter (2 ohm/0.1mH parallel components placed in series with tweeter) suggested for curtailing the top-end, IMO. It sounds really well balanced on anything from classical to bluegrass to jazz to rock to metal. I even listened to what I consider 'bright' recordings and nothing really came out harsh, hot, or sssibilant.
The bass is really something. They sound a lot bigger than they have a right to. Tympani, bass guitar, and stand-up bass are all tuneful and distinct in tone. Dynamics can make me jump, so that's very good.
Preferences-
I have found I like having the ultra-notch engaged. I'm not sure how to describe it, but it just sounds cleaner up on top to me, like a blacker background. Neither is bad on/off.
Same with the bypass caps in that they are also hard to describe, but I feel the addition of either messes with the spectral balance a smidge. Were I to pick one, the Silver Mica would be my choice since it just sounds cleaner on top, if not a little louder in level. The PIO do influence lower in the treble, but more of a vintage or analog combination. Again- I don't prefer the tweeters with either of these engaged over that of without both.
Looking good. I was looking at the mfg specs on the tweeter and it looks like the off-axis doesn't have the rise at 4kHz that the on axis response does. Where you have the on axis response set might be where it needs to be.
Keep an open mind, but don't let your brain fall out.
Been doing some more fiddling as of late, and I'm finally completely happy. Now I just need to finish the cabs...
I added a 1 ohm resistor in series right before the tweeter back in May to droop it's level some. While I liked them before (even with the rise), this seems to balance them out that much better. Again- I don't prefer either of the bypass caps here, but I do use the Ultrasonic notch.
I also fiddled more with the bass tuning a smidge. With the 1.5" added length, the bass was lost in some event rooms, whereas at 0.75", the midbass got a little thick for my tastes. I split the difference and added just under a half-inch thickness (half-inch ply) back into the length, making the optimal tuning measure at (Wait, what!?!?) 41 Hz, and I feel it does very well. The longer 1.5" addition was very good before for close-wall placement. I really did not expect it to be lower than it was prior at 42Hz at the 1.5" length. The port is shorter than it was before.
Again, It really did make a big difference. Hard to say what's going on...
And to anyone reading wanting to know the approximate nominal impedance since I was asked this past weekend in Grand Rapids, I would call this a 5 ohm load over all, with only one range dipping to 4 ohms below 50Hz.
I feel 4-6 ohm amplifiers will be kept happy here.
Very strange- I just looked at the older tunings and measurements. The initial was 50Hz as targeted, then added the 1.5" to 42 Hz, then removed 0.75" to 45Hz, then added back in 0.4" to 41Hz.
How strange, as I figured I'd be at 43/44Hz.
@Wolf said:
Since I have 4 of these tweeters, a second project has developed with the Seas U18. Hard to believe it's now a 10 year old driver design, but I've loved the U18 and U16 everytime I've heard them. The model is done, and I'm quite impressed!
It came out LR2 through the xover.
The higher Q tweeter rolloff coupled with the BDC signature needed a 3rd order of pretty low Q to achieve even a 2nd order rolloff.
The woofer has a dip in response at about 800-900, and this flattened out with the BDC signature, leaving a very minor magnitude dip. This coupled with the woofer's ability to work with a single coil makes this look really good to me! I used zaph's 10 year old FR measurement.
See for yourself:
(Image)
(Image)
If it wasn't for needing the Fs spike tamed, this would be a small parts count.
Measured results are now posted here. I ended up removing the 2.7uF lift-cap completely as it did not need it, and upping the series resistor to 5.6 ohms.
I'll have these at Meniscus/CSS this next weekend.
Comments
Not a bad likeness really:
InDIYana Event Website
You don't find it a bit bright?
For the most part, no. The bass range balances it out spectrally, and this is a bit of a smile curve. Mind you now, the measurement was taken at 10" above the tweeter axis, as I'm targeting an increasing lobe direction. Lower than that, and the mids will fill in a bit. It's not as bad as you think. Not all measurements are the same. It depends on application. I am not a downward-tilt fan. I prefer flat, and you have about a -2 to -3dB decline there.
As to the peaky bass, I ended up with 4 layers of batting the length of the main cavity to get it right. Any 'stuffing' killed the bass and made them really bright.
InDIYana Event Website
I've only had them together fiddling for a couple weeks. It might take a bit longer to make up my mind. Really though- most of what I've played have not been sssibilant or shouty. These tweeters are REALLY clean.
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To use your method with my preferred flat best-fit, this does not look anywhere as bad and is definitely only +/-3dB.
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If that's what you like to listen to, don't let me change your mind, it's your speaker after all. Based on my own experience I would expect that to be rather treble forward is all.
A few other people heard them yesterday, and no one felt they were bright. I really don't think the measurements I've shown are indicative of everything that is going on.
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Xovers before addition of 24uF cap, and reduction of 33uF Silver Solen to 25uF net combo Solen pair:
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Don't know if you have seen this video -
Pretty certain they did use the 6.5" woofer now. Apparently, there is a new Twenty5 23i edition, and it appears to have an upgraded tweeter.
It might be the 27TAC/GB, as the faceplate looks right.
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Corrected the render, and created the cutaway for the slot to scale as built:
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I have done a bunch of listening over the last few weeks, and there is no need to add the LR filter (2 ohm/0.1mH parallel components placed in series with tweeter) suggested for curtailing the top-end, IMO. It sounds really well balanced on anything from classical to bluegrass to jazz to rock to metal. I even listened to what I consider 'bright' recordings and nothing really came out harsh, hot, or sssibilant.
The bass is really something. They sound a lot bigger than they have a right to. Tympani, bass guitar, and stand-up bass are all tuneful and distinct in tone. Dynamics can make me jump, so that's very good.
Preferences-
I have found I like having the ultra-notch engaged. I'm not sure how to describe it, but it just sounds cleaner up on top to me, like a blacker background. Neither is bad on/off.
Same with the bypass caps in that they are also hard to describe, but I feel the addition of either messes with the spectral balance a smidge. Were I to pick one, the Silver Mica would be my choice since it just sounds cleaner on top, if not a little louder in level. The PIO do influence lower in the treble, but more of a vintage or analog combination. Again- I don't prefer the tweeters with either of these engaged over that of without both.
InDIYana Event Website
Looking good. I was looking at the mfg specs on the tweeter and it looks like the off-axis doesn't have the rise at 4kHz that the on axis response does. Where you have the on axis response set might be where it needs to be.
Sehlin Sound Solutions
Interesting take, Scott. Yeah, of course I planned that...
InDIYana Event Website
Been doing some more fiddling as of late, and I'm finally completely happy. Now I just need to finish the cabs...
I added a 1 ohm resistor in series right before the tweeter back in May to droop it's level some. While I liked them before (even with the rise), this seems to balance them out that much better. Again- I don't prefer either of the bypass caps here, but I do use the Ultrasonic notch.
I also fiddled more with the bass tuning a smidge. With the 1.5" added length, the bass was lost in some event rooms, whereas at 0.75", the midbass got a little thick for my tastes. I split the difference and added just under a half-inch thickness (half-inch ply) back into the length, making the optimal tuning measure at (Wait, what!?!?) 41 Hz, and I feel it does very well. The longer 1.5" addition was very good before for close-wall placement. I really did not expect it to be lower than it was prior at 42Hz at the 1.5" length. The port is shorter than it was before.
Again, It really did make a big difference. Hard to say what's going on...
And to anyone reading wanting to know the approximate nominal impedance since I was asked this past weekend in Grand Rapids, I would call this a 5 ohm load over all, with only one range dipping to 4 ohms below 50Hz.
I feel 4-6 ohm amplifiers will be kept happy here.
Thanks for looking...
Wolf
InDIYana Event Website
Very strange- I just looked at the older tunings and measurements. The initial was 50Hz as targeted, then added the 1.5" to 42 Hz, then removed 0.75" to 45Hz, then added back in 0.4" to 41Hz.
How strange, as I figured I'd be at 43/44Hz.
InDIYana Event Website
Somehow I failed to post this here! Simpler network drawing:
HiFiCompass' Yevgeniy recently did his round of testing on this tweeter, thought I'd link it:
https://hificompass.com/en/speakers/measurements/seas/seas-27tac/gb-h1825-06
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LOL, "simpler"
Measured results are now posted here. I ended up removing the 2.7uF lift-cap completely as it did not need it, and upping the series resistor to 5.6 ohms.
I'll have these at Meniscus/CSS this next weekend.
InDIYana Event Website
By the way, the Drottnar were measured with the stock and unmodified pair. The modded pair remain in my EMP build.
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Xover for Drottnar, in the Missing Link boxes:
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They appeared to be well received this weekend in Grand Rapids.
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Sorry for fuzzy image...
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Here's the one JR took:
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