So I was listening to Gretchen Parlato on my 0.40x's (3FE25) powered by my Silicon Harmony SE Class A *headphone* amp, and it sounded just glorious. I was curious so I put my measurement rig in place with a 8w power resistor and the Focusrite 2i4 as the interface and here is the FFT I get in REW (at the same volume level I listen at - about 0.71vrms). So one look at the FFT shows that it is dominant second harmonic, with a tiny bit of third, and nothing else, and the noise floor is flat and clean.
Silicon Harmony is the one in the case with fins:
707mV rms into 8ohms:
I agree with Bonjonno, these make excellent computer monitors.
Silicon Harmony is the one in the case with fins:
707mV rms into 8ohms:
I agree with Bonjonno, these make excellent computer monitors.
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Jon, do you have the schematic for your cap multiplier? I think the schematic on the first page of that thread looks different than the one you built? Thank you.
I don't think it is different - just use the critical part of the cap mx: the 220uF cap, 10k resistor, 1n400x diode, 220R gate stopper, 1uF and 1R5 snubber. The 4700uF output cap is optional - use whatever you have or the rail cap on the actual amp. Also, any N-channel enhancement mode MOSFET will work (IRFP240, IRF610, IRF510, etc). Even a little ZVN4306GTA and all SMT components can be used to make one that fits on a dime:
This one is courtesy of RaptoLightning who provides Gerbers for ordering your own - these are cap mx for my little pocket class A amp.
This one is courtesy of RaptoLightning who provides Gerbers for ordering your own - these are cap mx for my little pocket class A amp.
that's right. I followed xrk971's instructions as best I could. Just seven parts altogether. It would be the top right quadrant of the original schematic, minus the 4700uF cap. I used an IRF610 and a 1N4007. Put in my order for a bag of 50 1000uF caps and when that gets here I can build the cap array to complete the trifecta.
I see your aperture goes a lot higher than the one I have, following the sketches I found here for 0.4x. (unless I completely miscalculated it... which has been happening in the past! I'm far from fool-proof!)
Could it be the reason why I think it sounds boxy and muffled?
Could it be the reason why I think it sounds boxy and muffled?
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That looks nice Perceval. If you can show us a straight frontal perspective so we can see how big the aperture is relative to the driver cone. The height mainly controls the bass extension and power and the width of the aperture controls the mids and HF transmission. Try to make the aperture big enough so that it intersects the driver surround as the curved wing profile crosses through the driver face. That should open it up - it is sensitive so maybe 5mm to 10mm more removed from the aperture should do the trick.
It looks like you may have some rattles/buzz on your box, are these two measurements same drive voltage and mic at same distance away?
It looks like you may have some rattles/buzz on your box, are these two measurements same drive voltage and mic at same distance away?
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I want to thank X for submitting this design.
Many people do indeed seem to like it very much, but, unless there's something I can change, it is not for my own ears.
I have been enjoying the open sound that OB provides, but the miniK 0.4 with TC9 sounds stuffed, boxy and muffled to my ears. Plus, I guess the aperture "projects" the sound more than regular boxes without the aperture, seems good for sounds reaching farther away.
But for me, one of the reason why I prefer OB is I like the sound to be ambient, not "projected".
It's ok. I'm glad I built it and tried something else. I've been wanting to try this miniK for a long time.
In the end, I will keep the TABAQ, as I feel they are more balanced, and my, wonderful to my ears, OBs.
Many people do indeed seem to like it very much, but, unless there's something I can change, it is not for my own ears.
I have been enjoying the open sound that OB provides, but the miniK 0.4 with TC9 sounds stuffed, boxy and muffled to my ears. Plus, I guess the aperture "projects" the sound more than regular boxes without the aperture, seems good for sounds reaching farther away.
But for me, one of the reason why I prefer OB is I like the sound to be ambient, not "projected".
It's ok. I'm glad I built it and tried something else. I've been wanting to try this miniK for a long time.
In the end, I will keep the TABAQ, as I feel they are more balanced, and my, wonderful to my ears, OBs.
Yes, forgot to mention... measurements were with the exact same setup, minutes apart with nothing touched besides swapping the speakers to place them at the same place, and moving the mic up and down a bit to be in front of the driver. Mic is at 1m.
I'll try opening the aperture a bit more, see if that takes care of the boxy sound.
You don't get that kind of distortion with your miniKs? I thought it might me the design, as nothing rattles in the box.
So a thought just occurred to me. People who make this speaker out of foam core or cardboard seem to have a much better sound. It may be that wood is the culprit with the boxy sound. The foam core actually re-radiates some of the sound, possibly contributing to more passive radiation like a guitar body. Just a thought. If you have some cardboard - try making a quick and dirty one and see how it sounds. The foam core also seems to not have as much of an issue with the W notches you have with wood. Although Jim Shearer reported excellent results from his wooden 0.53x Karlsonator with dual TC9FDs earlier in the thread. I just notice both you and emuMannen reported closed boxy sound and both your builds are wood.
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Gotcha. The schematic is for dual mono dual rail, our TDA is stereo single rail. What is the watt rating for the resistor? Is 1uF cap critical? Can I go a little bigger or lower? I kinda like the idea of using TO220 like Jon did, is that enough heatsink for IRF610? What other MOSFET can I use? Or, teach me how to find correct equivalent for the MOSFET in that position. Thanks so much.
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The inside is 165mm (6.6") as per the drawing.
It looks wider because the outer shell in made of 15mm plywood. I used 5mm plywood for the labyrinth inside.
Hi, for what it's worth, I build mine out of wood, 0.4x with one TC9. Not boxy at all, no funny resonances or terrible peak that I notice. The inside is lined pretty heavily with 8mm felt.