sure looks good...
you sent some build links for the KCs. do you have one for this?
what about something slightly larger to accommodate mounting a tweeter on the same plane as the woofer and to provide more volume for woofer?
haven't taken any. got them free and mounted the BOFUs in them.
these are unsanded unfinished 1" mdf prototype enclosures, not the finished pearls that some folks sport on this group. not much to see...
re: Karlson coupler, K-forum-master Gregg/eeehaah is working on an Akabak model and predicts a smoothing and extension effect of a stub added to the rear chamber in a B20 coupler thread: anyone game to design a B20 coupler?
ok. thanks.
not certain which design was the "final" decision.
i like the idea of the karlson enclosure that puts the woofer at the floor with a slight angle, kinda like a stage speaker. it spreads the sound up into the room.
the small 1 ft3 volume enclosures don't seem to lend to any real bass below 60 hz, unless i've misread the graphs. the BOFU in a 3 ft3 ported box with a decent tuning will give 40 hz bass with no problem.
maybe a modification of the karlson will meet the goal of sound dispersion and decent 40 hz bass. but i can tell you that with the BOFU mounted at about a 48" height from the floor that the sound is dispersed into the room very well.
I have had some time to play with my BOFU's. I am putting the write-up on my web site. Here is a frequency response graph:
After a 50hr break-in, these guys do have a nice sound. I would describe it as warm, almost fat. The treble roll-of is obvious.
Bob
An externally hosted image should be here but it was not working when we last tested it.
After a 50hr break-in, these guys do have a nice sound. I would describe it as warm, almost fat. The treble roll-of is obvious.
Bob
nice work.
i use a 2.2 uf capacitor in series with the EPI dome tweeter. this seems to be a pretty good match with the BOFU mounted in the Hedlund cabs. really does need the tweets, and these are a good match to the BOFU, not too bright, good imaging, fair articulation.
this has a good sound that seems pretty linear, although i've yet to use the audio generator to note any deficiencies.
nothing is imposing. there is a bit of extra oomph in certain male voices, smokers, and DJ voices especially, but nothing objectionable.
with free cabs and cheap drivers, the sound is awesome!
don't have much more than 50 hours on the BOFUs, so these two sets are probably at about the same "ageing" stage.
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Just an update on the RS-B200's (my personal name for the redo on the RS T-100 with Pioneer B20's).....
I took one of the original RS T-100 woofers and applied duct tape around the steel stamped metal basket so that it was completely closed up and installed it in place of the butt ugly 10" wood circle that I initally used to cover up the 2nd woofer hole. Looks much nicer and there is no vibration in the woofer at all even at fairly high volumes.
Also experimented around with piezo tweeter and came to conclusion that the original L-pad wasn't working correctly and replace them with some new PE ones. Also found that an 8 ohm resistor across the terminals and a 0.47 uF cap before the L-pad give about the right volume adjustment for me. The piezo sounds extremely good and it really does surprise me on how well it integrates with the B20.
Now need to do some refinishing on the cabinets and the newly made speaker stands. All in all less than $100 for everything and these are very nice sounding speakers (and there is bass, not overpowering, but it's there).
I took one of the original RS T-100 woofers and applied duct tape around the steel stamped metal basket so that it was completely closed up and installed it in place of the butt ugly 10" wood circle that I initally used to cover up the 2nd woofer hole. Looks much nicer and there is no vibration in the woofer at all even at fairly high volumes.
Also experimented around with piezo tweeter and came to conclusion that the original L-pad wasn't working correctly and replace them with some new PE ones. Also found that an 8 ohm resistor across the terminals and a 0.47 uF cap before the L-pad give about the right volume adjustment for me. The piezo sounds extremely good and it really does surprise me on how well it integrates with the B20.
Now need to do some refinishing on the cabinets and the newly made speaker stands. All in all less than $100 for everything and these are very nice sounding speakers (and there is bass, not overpowering, but it's there).
some of the eps foam in a can will also help.
i always liked those RS cabinets. they have a nice veneer. if i could find some local, i'd do something similar.
i have a pair of EPI 200 cabs that take an 8" woofer that has a cut out just barely smaller than the BOFU cut out. the outer frame fits in the recess just fine.
wish there was a simple way to enlarge this hole and keep it symmetrical (round) to mount the BOFU. these are beautiful cabs.
>>> an 8 ohm resistor across the terminals and a 0.47 uF cap before the L-pad give about the right volume adjustment for me. The piezo sounds extremely good and it really does surprise me on how well it integrates with the B20.
Yup, this works really great with the B20! You don't even need the L-pad. Not sure how it measures but it does sound 'correct' to me.
Zilla
Yup, this works really great with the B20! You don't even need the L-pad. Not sure how it measures but it does sound 'correct' to me.
Zilla
I think the L-pad just gives it a little bit of control at the speaker level and not having to do anything with tone controls. I had to turn my down some because it was till a little too "high" in the room where the speakers are playing. But now they seem to fit right in with the B20. Very, very pleasant to listen too and if you have not heard the B20's, then find someone that can audition them for you. Definitely a "best bang for the buck" out there in audio land and easy to build for the novice or for that matter the experts.
A big rasp. How round it remains depends on the care you take to keep it so. With the B20 you have a fair amount of wiggle room.
dave
Creative Sound Trio12 Reworking surplus cabinets to create a new subwoofer. Article By Jeff Poth
First pic is using a readily available drill-drum sander to expand a hole. Works just great!
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