Hey there. Sorry bout the TLDR.
So, I'm making a loudspeaker from scratch. Magnets, magnet wire etc. I've gone down the rabbit hole a bit and Id just like a little advice.
I'm trying to make a set of speakers, single drivers in each, that will play in the midrange frequencies. It's a school project, and I don't think I'm aloud to use an amplifier, other than what is supplied from my audio source, like a laptop or a smartphone.
My question is, what dc resistance should I wind my voice coils to? I know impedance is different than dc resistance, but I can only measure dc with my multimeter. From what I understand, 4 ohm impedance (roughly 3 ohm dc) is too low because it will try to draw too much power. Should I be shooting for 6 or 8 ohm impedance?
And last but not least. Why are voice coils given these even number impedances? Can't they have any impedance as long as the amp can supply enough power? I know impedance changes throughout frequencies. Whats the big deal on the even number impedances.
So, I'm making a loudspeaker from scratch. Magnets, magnet wire etc. I've gone down the rabbit hole a bit and Id just like a little advice.
I'm trying to make a set of speakers, single drivers in each, that will play in the midrange frequencies. It's a school project, and I don't think I'm aloud to use an amplifier, other than what is supplied from my audio source, like a laptop or a smartphone.
My question is, what dc resistance should I wind my voice coils to? I know impedance is different than dc resistance, but I can only measure dc with my multimeter. From what I understand, 4 ohm impedance (roughly 3 ohm dc) is too low because it will try to draw too much power. Should I be shooting for 6 or 8 ohm impedance?
And last but not least. Why are voice coils given these even number impedances? Can't they have any impedance as long as the amp can supply enough power? I know impedance changes throughout frequencies. Whats the big deal on the even number impedances.
Before going down the road of winding custom coils for optimized power transfer you should certainly do two things, be certain about the project rules, and learn as much as possible about the output section of your selected source. Actual DCR in any impedance group of speaker can vary almost 2:1 depending on the whims of the manufacturer, and often approaches half the rated impedance. If you're designing blind for a headphone output, 10 to 16 Ohms DCR is probably a better minimum target, as many portable audio products are designed for 16 ohm phones. 4/8/16/32 ohms is just a convention. It's otherwise meaningless.
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Common size for voice coil are mostly in inches, 1", 1.5", 2",etc. There are odd sizes.
Your approach maybe:
- Find a suitable winding machine
- Design your bobbin
- Choose your wire gauge
- Glue for bonding the wires
- Voice Coil former material
No. of turns you have to explore, but my recommendation probably no less than 30 turns.
And wire gauge, no less than 0.2mm but still wire gauge depends greatly on the bobbin diameter and turns to achieve required impedance and DCR.
Your approach maybe:
- Find a suitable winding machine
- Design your bobbin
- Choose your wire gauge
- Glue for bonding the wires
- Voice Coil former material
No. of turns you have to explore, but my recommendation probably no less than 30 turns.
And wire gauge, no less than 0.2mm but still wire gauge depends greatly on the bobbin diameter and turns to achieve required impedance and DCR.
And checkout Youtube for videos, I've definitely seen at least one video of voice-coil construction that will be very useful.
A cordless screwdriver can be pressed into service as an ad-hoc winding machine with some
bodging. There are cheap hand-crank chinese coil winding machines too, which are worth looking at, the one I have is pretty robust and has a mechanical turns counter.
A cordless screwdriver can be pressed into service as an ad-hoc winding machine with some
bodging. There are cheap hand-crank chinese coil winding machines too, which are worth looking at, the one I have is pretty robust and has a mechanical turns counter.
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