@xrk971, Have you personally heard a K15? When I built one about 10 years back, It's resonant above the midbass range with all that sound bouncing about in the front chamber. Great punch though, well suited for bass duties. For midrange, not so much (depending on your tastes). Drivers I tried the design with were University C15W (woofer), Stephens Trusonic 206AXA (co-ax), maybe a 12" pyle 1298 (woofer) with an adapter plate too.
Not what I'd recommend crossing over to an OB that high. Might work crossed over lower, about 200 Hz.
@DeonC, I played with winged open baffle Karlsons many years ago (much like your design). The wings broadened the disperson a bit but that was it (apart from the tone chamber affect).
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I have only heard a Karlsonator but have heard many good things about the mid bass punch of the K15. XO freq just depends on how many drivers and "ways" Deon ends up with and how low his tops can go. I have run an OB XO at 375 Hz and it sounded great. One thing that helps is to put some polyfill behind the Karlson aperture (not visible) and that cleans up some of that bounce.
Oh yes, but not just any valve amps. I specifically went for the JWN Amps, because they, for the first time, were described in the kind of terms that got my attention, terms I like: "3D spaciousness", "vivid tonality", "strong and deep bass", "follows the most complex beat without getting confused", and, most of all, "if the music is any fun at all you'll be grinning too, because the enthusiasm of the musicians comes right through". All these from Lynn Olson's review on Positive Feedback, and Lynn does not easily give such high praise. Read more in his review:
A Quick Review of the JWN Amplifier by Lynn Olson
Would it work if I mount the woofer slightly lower down? I am going to add some damping in the form of carpet underfelt on the inside of the Klam. I was always planning to do this to make sure that the midrange does not go bouncing around and resonating inside the Klam. I am also going to damp the rear wave of both the straightforward OB section as well as the Klam. For the OB section this will consist of one layer of carpet felt. I may even add a few holes in the felt and adjust for the best sound. The Klam will probably get two layers over the rear K-slot, meaning the rear will be halfway between OB and cardioid. Here is a thread that talks about doing exactly this:
Attenuating rear radiation on open baffle
Do you think my idea of the carpet felt inside the Klam could help for this. I am adding it for this exact reason.
Did you not get better punch than the standard OB? I am curious to try this, but given your feedback I am thinking twice about it. I still might just initially build the slot with some chipboard to see what happens. Chipboard is cheap enough to experiment with and will be no great loss it the experiment fails.
Thanks,
Deon
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Deon & XRK.
1. Stuffing should help with the resonances I mentioned.
2. It's been so long ago that I don't recollect whether the K-slot helped in the open baffle experiment. I think it didn't but once again, I don't clearly remember. Sorry.
One thing I do remember from my experiments with larger bandpass Karlsons is that they require a strong motor driver to perform well and hit hard. Weaker motors just didn't sound the same, subjectively. On the other hand, you're looking at open baffle applications where weaker motors (high Qts) are better.
Klam style enclosures (http://www.diyaudio.com/forums/mult...res-technique-whats-happenin.html#post1276679) operate on a different principle and might work better with weaker drivers. Maybe freddy will chime in and explain how they work. I haven't messed with them.
I'd recommend you try with a cheap prototype build and let us know.
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Karlson loading an OB speaker
It seems that if you are going to load an open baffle speaker for bass, that it would be best to load both the front and back wave. This way both sides of the driver will be loaded down the same which should reduce distortion.
I have the same thoughts about producing open baffle bass both for midbass (50 to 200 hz), and deep bass (<50hz). Although for the 50 to 200 hz, I may just use a Karlson cabinet (or at least try it).
Retsel
It seems that if you are going to load an open baffle speaker for bass, that it would be best to load both the front and back wave. This way both sides of the driver will be loaded down the same which should reduce distortion.
I have the same thoughts about producing open baffle bass both for midbass (50 to 200 hz), and deep bass (<50hz). Although for the 50 to 200 hz, I may just use a Karlson cabinet (or at least try it).
Retsel
It seems that using a K15 with a nice powerful low Qts 15 in driver as a very efficient 95 dB+ efficiency helper bass woofer from 50 Hz to 150 Hz could be really useful for many applications like OB, or FAST, etc. Surprised it has not been done more often. Freddi probably knows of an example though. Man, I really wish I had a pair of K15's with a nice 95 dB to 98 dB efficient 15 in PA woofer like a Kappalite or Deltamax...
Blake at Fullrangedriver bumped into "this" - you might not have the biggest K - I can't tell if there's significant front cavity
nor vent (if any) placement - I don't belong to FB so someone might ask
https://www.facebook.com/photo.php?...012.1073741851.365921370192814&type=1&theater
nor vent (if any) placement - I don't belong to FB so someone might ask
https://www.facebook.com/photo.php?...012.1073741851.365921370192814&type=1&theater
An externally hosted image should be here but it was not working when we last tested it.
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I was curious. How would a MOAK for two of these following drivers look:
GR SW-12-04
fs:21 Hz
BL: 13.7
VAS: 137 L
Qms: 4.308
Qts: 0.279
Sd: 490 cm2
Re: 3 ohms
Xmax: 16 mm
I am hoping it will be smaller than the MOAK for the other drivers. My idea for a MOAK using the Leak drivers have been vetoed by the landlord (something along the lines of 'if you build it, you better be able to live in it, because you won't be living here'). I am hoping these will make for a smaller solution. Height is not the problem, huge width and depth is.
Thanks,
Deon
GR SW-12-04
fs:21 Hz
BL: 13.7
VAS: 137 L
Qms: 4.308
Qts: 0.279
Sd: 490 cm2
Re: 3 ohms
Xmax: 16 mm
I am hoping it will be smaller than the MOAK for the other drivers. My idea for a MOAK using the Leak drivers have been vetoed by the landlord (something along the lines of 'if you build it, you better be able to live in it, because you won't be living here'). I am hoping these will make for a smaller solution. Height is not the problem, huge width and depth is.
Thanks,
Deon
Is that a landlord or a SWMBO?
Nah, no significant other on this side. OTOH, if I find the right one, she will love music as much as I do and not complain about the giant, brick-outhouse sized boxes in the listening (or is that living) room.
I will see what I can do to make it the "Baby-momma of All Karlsonators" or BOAK
Thanks. I am looking forward to it. As I said, height is not a problem, the girth (WxD) is.
Absolute max is 50cm x 50cm, outer dimensions. IOW inner dimensions of 45cm x 45cm. Height can be up to 2.5m, or even as much as 2.7m.
I have been busy with my own project lately - should have something soon when I get a breather.
No probs. You help everyone else so much and I am thankful for all the help you've given me. I was just curious, which in turn made me unnecessarily hasty and impatient. Sorry for that. I really hope whatever you are busy with turns much better than expected. It would be great if you built something really mind-blowing for yourself.
Deon
He he he... eardrum blowing would be more apt a description....
Well, here is where I quote GM's tagline: Loud is Beautiful if it's Clean!
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