SB Acoustics SB65WBAC25-4 - What to do?
- Thread starter xrk971
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I got a couple SBA65WB a while back. I now have them in some small 15cm spheres above an up firing mid bass. The enclosure is 1.5L with some stuffing added. I have them high passed at 5kHz with a first order passive line level filter in the input stage of my power amp.
Although they are nowhere near run in I really like them. I am listening to them slightly off axis and they perform very well as a tweeter. Here's a pic of my very rough prototype. The mid bass enclosure is soon to become a sphere too. Oh the 6.5" mid bass is doped and run full range
Although they are nowhere near run in I really like them. I am listening to them slightly off axis and they perform very well as a tweeter. Here's a pic of my very rough prototype. The mid bass enclosure is soon to become a sphere too. Oh the 6.5" mid bass is doped and run full range
We made a pair IKEA -coconut version consisting of 2 bowls, cardboard tube w/ leather.
The hole in the rear bowl serves as a resistive port.
The low internal volume due to that a small subwoofer (8") are hidden under the desktop, no intention to force any low end out of the SBA's.
This was tuned with a notch filter for desktop listening. Don't remember the component values.
The hole in the rear bowl serves as a resistive port.
The low internal volume due to that a small subwoofer (8") are hidden under the desktop, no intention to force any low end out of the SBA's.
This was tuned with a notch filter for desktop listening. Don't remember the component values.
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Thanks XRK. I am starting the final build very soon.
I haven't tried crossing at 1K but I have thought about it. There is a dip in the ears sensitivity around 1K which is why I considered it.
My filters are 1st order passive line level.
Do you think it will be much better ? I was trying to avoid filters if possible hence the doped mid bass run fully open.
Thanks
Which model uses the SB65? From the specs, I see 8ohms and 16ohms options and 90+dB sensitivity. This cannot be the SB65, my guess it that they are using Faital Pro 3FE22-8 or 16. In the parallel it can be as high as 97dB at 2.83v at 4ohms (91dB +6dB). The 3FE22/3FE25 are the only small drivers I know of that are in that sensitivity range and offer flexible impedances.
Interesting trick to cross them like an XY mic for uniform dispersion, we should try this for DIY:
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There's a smaller bump at ~12kHz, too, which shows up off-axis as well. IMO, these can be annoying. The peak on mine turned out to be about 20kHz, and drops off quickly off-axis. I ignored this, in favour of sorting out the ~12kHz instead.
At some point, I'd like to try the SB65 as a 700Hz-7kHz midrange, with a 0.5" tweeter above.
Chris
It has a ~1" dia. VC, so ~13543/pi = ~ 4311 Hz, ergo the BW above ~ this point is normally radiating off the dustcap/glue joint, so recommend the $0.98 tweak and for the super keen of hearing, put a dot of damping on its crown.
The problem with a separate tweeter is you will get lots of lobing since you can't get the tweeter close enough to the SB65. If you want better high frequency response I would suggest using a smaller FR driver or a large format tweeter in a waveguide. In my experiments, however, while it isn't the best tweeter I have found it to be good enough. Any attempts to cross to a separate tweeter have just made everything worse.
To solve the 10-20 khz bump I just adjust the top end down with some EQ.
I tried to use 4th order slopes.
2 driver tall mini-array SB65 with back to back Dayton PTMini planar tweeters (4 tweeters in total) as close as physically possible (4cm) beside it measured in the horizontal plane. Since I would have used them in an array then placing the tweeter above or below is not possible. In the end, however, placing tweeter above or below will just hide the lobing in the horizontal plane but the problems are still there in the off axis repsonse.
The lobing can probably be mitigated more with much sharper slopes but is it really worth it then since sharp slopes are no free lunch. In the end I decided that the high end of the SB65 is good enough that I didn't add a tweeter. And it has decent rear output too, a good enough dipole response up to ~ 10 khz before the rear starts to fall off which to me was good enough.
Might work better if the drivers can be placed closer, say in front of the SB65 like this array. That was not an option for me, however, since I was building a dipole array.