Hi all guy's. How about scaling down a K15 to a 5 or 6 inch speaker?
Did anybody try this?
Thank you.
Did anybody try this?
Thank you.
See the Karlson thread or Speaker thst kicks butt thread. Short answer is no it won't work. The K15 is a specially configured hybrid dual chamber reflex with a big vent reflex horn front chamber. The dimensions when scaled below 12/15 scale collapse the bass response. It has been tried by many and you can see measurements which show very little bass below 100 Hz. This is also seen in my models of the K15 in AkAbak http://www.diyaudio.com/forums/full-range/213594-karlson-10.html#post3528706, which shows that the bass response is shot if scaled below 12/15 factor. If you want successful scaling, it will work with GregB's Karlsonator which is a hybrid ML TQWT transmission line and Karlson coupler output horn. This scales very well and is shown in sims to scale down to even 3.5 in drivers in tamdem. A 5 in driver will be about 0.53 to O.67X scale. See example in this thread http://www.diyaudio.com/forums/full-range/239338-mini-karlsonator-0-53x-dual-tc9fds.html
OK, thanks for the reply. I made 3 of them, one 12 and two 15", and now I want scaling them down to put in a table "empowered" from a class D audio amplifier built inside the PC cabinet.
As the 5" inch coaxial spks I have, their bass response is not expected to go below the 100Hz limit.
Which is the listen experience difference between the original Karlson, and the "dutch Karlson" (Those with the slotted board in place of the entire vent)?
As the 5" inch coaxial spks I have, their bass response is not expected to go below the 100Hz limit.
Which is the listen experience difference between the original Karlson, and the "dutch Karlson" (Those with the slotted board in place of the entire vent)?
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Osvaldo,
The mini Karlsonator is a perfect table radio speaker. See my last post in 0.53X Karlsonator thread. One of the finest sounding table top speakers I have heard. With dual drivers you don't need a stereo to mono amp which is hard to find in compact class D amps.
Regarding the slit vents vs hole vent in K15, I have heard that the slit vents induce distortion when driven by sine waves. I think rectangular hole vent Karlsons work better.
If you have TS params for your 5 in drivers, I can run sim in Karlsonator for you and hone in on optimum scaling tonuse,
The mini Karlsonator is a perfect table radio speaker. See my last post in 0.53X Karlsonator thread. One of the finest sounding table top speakers I have heard. With dual drivers you don't need a stereo to mono amp which is hard to find in compact class D amps.
Regarding the slit vents vs hole vent in K15, I have heard that the slit vents induce distortion when driven by sine waves. I think rectangular hole vent Karlsons work better.
If you have TS params for your 5 in drivers, I can run sim in Karlsonator for you and hone in on optimum scaling tonuse,
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Class D amplifier is made stereo of my own, no need for mixing both channels.
Photos 1 and 2 are the class D self-designed amp.
In photo 3 can see two black boxes at the job, I want to make 2 K's 5" for replace them.
Photos 1 and 2 are the class D self-designed amp.
In photo 3 can see two black boxes at the job, I want to make 2 K's 5" for replace them.
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Ok, so you plan to use two speakers in stereo? When I think of table radio, I imagine single mono style box. Works well in stereo too.
No, the amp board in photos 3 and 2 is inside the PC cabinet at photo 1 right down corner, powered from +-12V of the mainboard's SMPS (Blue and yellow cables plus black earth).
Sorry for the mistake in early post.
Sorry for the mistake in early post.
Nice IR2110 and MOSFET self oscillating designs there. I think the mini 5 in cabinet Karlsonator would be perfect here as it is againsta a back wall and is compact.
It isn't self oscillating, it is fixed frequency about 280KHz. See the CD4047 oscillator near the end of the board. This is my schematic...
Why two speakers?
Why two speakers?
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Ok, missed the oscillator. I like fixed frequency better actually. How many watts can you get? For my mini Karlsonator I went with two drivers because I had them around but wanted more SPL, efficiency, and dynamic range, yet retain the very nice high end that a 3.5 in full range offers (the Vifa is almost tweeter like). After building one cabinet, rather than driving the one speaker with the drivers I parallel for 4 ohms I said what the heck I will hook up right and left to each driver. It turned out to sound really nice. After I made the other speaker mate I ran it paralleled and in stereo with two speakers and that sounds really good. I can't believe how loud this thing can get when driven by the 50 w/channel TPA3116D2 amp. I never went above 50% volume setting. Too loud, my wife would complain and I am in the basement. As a mono speaker it works well as a background music radio with superb clarity and bass punch.
No more than a 6-7 watt, as the speakers are 8 ohms into ±12V, and as they are in the working table at job, usually I listen internet radios at no more than, say, ,5W. Output MOSFET´s are IRF510, but at full power with sine wave and resistive load they don't heat noticeably over ambient temperature, although 280KHz is a high frequency to this MOSFET's. IR2110 warms a little.
In fact, the amplifier has made is more a defiance than a true necessity. I did it with the parts I usually have at hand, as industrial electronics parts service and repair. I didn't need to buy anything specially for it. Before it, there was a STK amplifier also inside the PC cabinet.
Returning to the topic, I want to use 5" coaxial speakers from car speakers, re-coned by a friend whose job is justly speaker repairing and restoration. Some years ago I knew him at the University, once repaired for me an old rhola-type electromagnetic field type speaker, that works pretty fine. The field coil was 1500 ohms.
In fact, the amplifier has made is more a defiance than a true necessity. I did it with the parts I usually have at hand, as industrial electronics parts service and repair. I didn't need to buy anything specially for it. Before it, there was a STK amplifier also inside the PC cabinet.
Returning to the topic, I want to use 5" coaxial speakers from car speakers, re-coned by a friend whose job is justly speaker repairing and restoration. Some years ago I knew him at the University, once repaired for me an old rhola-type electromagnetic field type speaker, that works pretty fine. The field coil was 1500 ohms.
Osvaldo,
So the amp was cobbled from your employer's parts bin? They of course, don't permit purchase of hifi grade audio amps for workstation use - way to go 🙂 If you heatsinked the mosfets could you get more power from it? Not that you would need it... The nice thing about Karlsons is ability to take lots of power as cone motion is very small compared to a BR.
So the amp was cobbled from your employer's parts bin? They of course, don't permit purchase of hifi grade audio amps for workstation use - way to go 🙂 If you heatsinked the mosfets could you get more power from it? Not that you would need it... The nice thing about Karlsons is ability to take lots of power as cone motion is very small compared to a BR.
I can't understand what do you say as "cobbled", but I did it with materials of normal usage at the job. As the owners don't understand too much of electronics, and I had done it when they go to client's address, and I am alone. These are cheap materials normally in the small plastic boxes at the left upper side of the photo 1.
Here, there is a proverb that says : "cuando el gato no está, los ratones están de fiesta" (when the cat isn't at home, mice do a party), :-D
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