fake Druid = made them some years back with original B102 and APT80 copy - pipe fully open on the bottom - spike height does some tuning - two cabinets come from one sheet so I was happy. It works well with the cheap Visaton BG20.
Eminence's new B102 is weak in mids and has no highs. It will substitute for BG20 and BOFU from 2K down.
12LTA might be fun in a 1XSd cross-section pipe this height.
2pi effect of base gap
Eminence's new B102 is weak in mids and has no highs. It will substitute for BG20 and BOFU from 2K down.
12LTA might be fun in a 1XSd cross-section pipe this height.
2pi effect of base gap
An externally hosted image should be here but it was not working when we last tested it.
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FWIW here are my measurements of the mini Karlsonator for CHR70. (post #640 http://www.diyaudio.com/forums/full...sonator-0-53x-dual-tc9fds-65.html#post3919476
Impedance
Nearfield SPL - very raw and unsmoothed
I seem to be getting a touch of proximity effect with the nearfield. 1m and .5m did not show that slight rise at the bottom end, but i run into the usual floor bounce and room effects, as well as issues with the urban sounds from outside...
This isn't the final version, and the stuffing is minimal. I'm going to take more readings when I've tweaked them to my satisfaction. What i have noticed so far is adding felt to the front chamber does not eat up the highs as I feared, but does clear up the sound and 'reverb' quite a lot subjectively. It also reduced the severity dip at 2kHz be 3db or so. This seems to be associated with reflections from the wings just in front of the driver.
Impedance
An externally hosted image should be here but it was not working when we last tested it.
Nearfield SPL - very raw and unsmoothed
I seem to be getting a touch of proximity effect with the nearfield. 1m and .5m did not show that slight rise at the bottom end, but i run into the usual floor bounce and room effects, as well as issues with the urban sounds from outside...
This isn't the final version, and the stuffing is minimal. I'm going to take more readings when I've tweaked them to my satisfaction. What i have noticed so far is adding felt to the front chamber does not eat up the highs as I feared, but does clear up the sound and 'reverb' quite a lot subjectively. It also reduced the severity dip at 2kHz be 3db or so. This seems to be associated with reflections from the wings just in front of the driver.
hey Greg B. - we were just starting to talk about your mini-Karlsonator at fullrangedriver right when the forum died. Its interesting that it sounds better than your direct radiator Alpair. The impulse response above is excellent. My Karlsonator 12s sound great but need to throw out a ton of stuff to get enough room to set them up. I'm still thinking about a regular "K10" but am stuck at what to do to make sure it will be better than an old attempt. A little K10 imo should play strong to ~120dB peaks and not overheat or strain - be nice to tame the "hit" - but not neuter the effect. I wish B&C's 10FW64 would work - it might be even a bit too strong for a regular K (? - I like the sonics of 12pe32 in K12 just fine) - on the cheap, Delta10a is dynamic and has good thermal characteristics.
on the Karlsonator side, we were discussing a Karlsonator10 - I'm guessing just adding two inches of width to your Karlsonator8 will work with Beta10cx which behaves in classic K in LF much like a BG20 8". 2" extra width and no other changes only adds maybe 500 cubic inches total airspace. Thejessman's graph of Karlsonator8 with BG20 and just a lined stub was very encouraging.
I'm pretty sure Nirvana's 10s will sound as good as they can in a Karlsonator as my old AN10 was exciting and dynamic in the Karlsonator12 - it had a few rough spots which are inherent to the driver and should improve with a bit of felt on the inside of the wings in the driver region. In contrast, 12lta is so mellow that nothing is needed other than a helper tweeter.
thanks for the Karlsonator design.
on the Karlsonator side, we were discussing a Karlsonator10 - I'm guessing just adding two inches of width to your Karlsonator8 will work with Beta10cx which behaves in classic K in LF much like a BG20 8". 2" extra width and no other changes only adds maybe 500 cubic inches total airspace. Thejessman's graph of Karlsonator8 with BG20 and just a lined stub was very encouraging.
I'm pretty sure Nirvana's 10s will sound as good as they can in a Karlsonator as my old AN10 was exciting and dynamic in the Karlsonator12 - it had a few rough spots which are inherent to the driver and should improve with a bit of felt on the inside of the wings in the driver region. In contrast, 12lta is so mellow that nothing is needed other than a helper tweeter.
thanks for the Karlsonator design.
Thanks for sharing the measurements GregB. It is also an interesting test to take a measurement without the wing panel in place. The fb will rise but whatever anomalies that result from wing-induced interactions with the cone will be apparent. The use of damping or stuffing in the front cavity can be very effective.
Sure thing.
That graph was taken about a month ago. It was just the initial test. The cabinets had minimal damping and nothing in the front chamber. After much tweaking and goofing around (err, experimenting), I did manage to get rid of most subjective 'reverb' coloration as well as improving the freq response somewhat. Final FR still has a dip from 1.5 to 3k or so, but lessened considerably from that seen in the raw response above.Final scheme for damping was:
Rear chamber: ~10g polyfill in the 'stub', ~3/8" felt blanket on the bottom and one side wall behind the driver, 3/4" foam on the other side. Polyfill behind the driver itself sucked the life out. Lining the sides and bottom was much better.
Front chamber: thin craft felt on the wings right in front of the driver only, and on one side of the front chamber - also in front of the driver only. Adding too much damping to the front makes the sound go subjectively 'dead' fast.
I did take a wingless measurement or two at some point, but don't think I saved them.
There was one other thing I was curious about. I tested the effect of a radiused edge on the wings, and concluded that it really doesn't make a difference that can be measured. Granted my radius was small (~4mm) due to the 10mm BB. With larger radii it's possible it might do something, but likely not much.
Finally! Finished the dual TC9FD mini-Karlsonators using 0.5” plywood!
The Tolex vinyl from Parts Express is attached with contact cement—the kind that is used for bonding Formica to counter tops in kitchens. Needed 5 coats (applied w/ disposable sponges) to get the film thick enough to grab onto the rough surface of the vinyl.
Note grill cloth attached (again with contact cement) to the inside K-slot; run out to the edges so that the cloth acts as the gasket. Screw heads will get dabs of paint to make them less painfully obvious.
I also added a thin fiber batting material to the inside of the K-slot. Without this, there was a slight hollow sound, which I assume was due to internal reflections of mid- to high freqs from the front of the drivers bouncing around in the cavity behind the K-slot.
When I built a single mini-K in foam core (to try out the design), I wired the drivers in parallel for 4 ohms. One of the amps I intend to pair these with isn’t rated for 4 ohm loads. So I tried wiring these in series for 16 ohms. The result was a dark sound— rolled off in the highs. I assume this results from the voice coil inductances adding. I re-wired them in parallel, then put a 2 ohm mills resistor in series with them to yield 6 ohms. Much better!
So, how do they compare with other speakers I have built? The TC9FDs (at least in this enclosure) are not as articulate as the Fostex drivers I have used. Compared with the FE108eSigma Metronomes: the mini-Ks don’t have quite as much bass extension and they become congested on complex music (like large scale orchestral) at lower volumes. But they are better at filling their intended space at STC’s rehearsal studio than the 108 Mets. And I paid about $40 for the four TC9FDs, while a pair of 108’s will cost you about $225.
Summary: the mini-Ks are inexpensive, fun, & suited to my purpose!
Cheers, Jim
The Tolex vinyl from Parts Express is attached with contact cement—the kind that is used for bonding Formica to counter tops in kitchens. Needed 5 coats (applied w/ disposable sponges) to get the film thick enough to grab onto the rough surface of the vinyl.
Note grill cloth attached (again with contact cement) to the inside K-slot; run out to the edges so that the cloth acts as the gasket. Screw heads will get dabs of paint to make them less painfully obvious.
I also added a thin fiber batting material to the inside of the K-slot. Without this, there was a slight hollow sound, which I assume was due to internal reflections of mid- to high freqs from the front of the drivers bouncing around in the cavity behind the K-slot.
When I built a single mini-K in foam core (to try out the design), I wired the drivers in parallel for 4 ohms. One of the amps I intend to pair these with isn’t rated for 4 ohm loads. So I tried wiring these in series for 16 ohms. The result was a dark sound— rolled off in the highs. I assume this results from the voice coil inductances adding. I re-wired them in parallel, then put a 2 ohm mills resistor in series with them to yield 6 ohms. Much better!
So, how do they compare with other speakers I have built? The TC9FDs (at least in this enclosure) are not as articulate as the Fostex drivers I have used. Compared with the FE108eSigma Metronomes: the mini-Ks don’t have quite as much bass extension and they become congested on complex music (like large scale orchestral) at lower volumes. But they are better at filling their intended space at STC’s rehearsal studio than the 108 Mets. And I paid about $40 for the four TC9FDs, while a pair of 108’s will cost you about $225.
Summary: the mini-Ks are inexpensive, fun, & suited to my purpose!
Cheers, Jim
Attachments
Jim Shearer,
Awesome build - those look fantastic! Nice touches you added to make it look like a finished professional speaker. Good idea about adding batting on inside of K panel. 2 ohm resistor was a good save! Glad they worked out - and the value on $40 worth of drivers is as you can see. Very good.
Awesome build - those look fantastic! Nice touches you added to make it look like a finished professional speaker. Good idea about adding batting on inside of K panel. 2 ohm resistor was a good save! Glad they worked out - and the value on $40 worth of drivers is as you can see. Very good.
Man, I missed this post while I was out of town. Nice job on the CW style mini K. They look awesome!!
Not that I know of, but it might work out ok. Since Fs is relatively high, the bass extension may be limited.
Jim Shearer's post has me wondering if the FE108EZ will fit into my own mini Karlsonators. IIRC the frames are about the same size as the CHR70. Might be an interesting experiment to shoehorn them in there, since I have a pair in my stash.
Jim Shearer's post has me wondering if the FE108EZ will fit into my own mini Karlsonators. IIRC the frames are about the same size as the CHR70. Might be an interesting experiment to shoehorn them in there, since I have a pair in my stash.
I would use two of them in parallel in a 0.53x scale tall and deep x 0.40x scale wide. Goes down to about 62Hz.
Hello
at first i was interested in a new fullrange driver:
But then i was very surprised: only measurements of the driver in a desktop box with bsc...
Why ever would someone only post those???
"See frequency response measurement taking in a desktop cabinet design with baffle step loss compensation filter.*
See off axis responses taken at 0, 10, 20, 30, and 40 degrees off axis in the same cabinet."
Unbelieable imho!
Or might there be something worth "hiding"?
Regards
at first i was interested in a new fullrange driver:
But then i was very surprised: only measurements of the driver in a desktop box with bsc...
Why ever would someone only post those???
"See frequency response measurement taking in a desktop cabinet design with baffle step loss compensation filter.*
See off axis responses taken at 0, 10, 20, 30, and 40 degrees off axis in the same cabinet."
Unbelieable imho!
Or might there be something worth "hiding"?
Regards
I was kind of disappointed with the data provided also. This driver is similar to the beloved TC9FD (same fs, same xmax, about same frame size) and may have been a competitor but looking at that data I will just stick with the TC9FD. This driver does have a lower Qts, but not by much and it has a phase plug which IMO are not needed and detract from ability of dustcap to act as a dome tweeter in a waveguide that the TC9FD does.
0.40x scale (all around scale) gives nice flat response to 80Hz, and 72Hz (-3dB) with no BSC needed. If you wanted to enhance bass punch, add 0.5mH and 2ohm BSC. Looks nice actually.