Questions tagged [sound-card]

A device internal or external to a desktop PC or laptop that facilitates the input and output of audio signals, including for recording and playback.

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1answer
59 views

USB port noise and how to deal with it, or avoid it?

I am designing and testing a DIY microphone. The idea is to amplify an electret mic signal before sending it to a PC's sound card to avoid using digital gain. The circuit just uses 2 opamp OPA2134PA, ...
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4answers
223 views

Is signal from electret microphone capsule (with FET) inverted?

Can I assume that the signal from an electret microphone capsule is inverted due to common source configuration of jfet? I would like to have non-inverted signal on my sound's card line input. Then I ...
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2answers
267 views

How do I calculate sound pressure level (dB SPL) from headphones at a specific setting on my sound card?

I am using headphones with sensitivity 102 dB SPL / 1 Vrms with impedance of 300 ohms. For a particular volume knob setting on my sound card embedded with a headphone pre-amplifier, I would like to ...
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1answer
49 views

Plug an Android phone into a USB sound card using a 4-poles 3.5 mm cable [closed]

I thought that it can be helpful for other people that are doing testing on mobile devices these days, so I would like to know if one can plug an Android phone into a USB sound card using a 4-poles 3....
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3answers
130 views

I need a pre-amplifier for my sound card with high gain without noise [closed]

I'm trying to make a pre-amplifier for my PC microphone with high gain and low noise. I tried a few circuits but they had a lot of noise and low gain. How can I make a preamplifier with high gain and ...
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1answer
473 views

How to shield your microphone the best way

I hope this is not a too simple question for this forum. I have an issue with EMI/RMI on a microphone I am building. It's picking up noice from wifi hubs, computer screens and mains. I do not want to ...
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2answers
311 views

What is the AUX_IN and CD_IN connection on old Soundblaster sound cards?

What is the AUX_IN and CD_IN 4-pin connection on old Soundblaster sound cards? The card's model is CT4170. Here is an example I think its some sort of input. Is there any schematic which tells me ...
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2answers
515 views

Electret microphone to USB soundcard

I am trying to interface a suite of aviation audio headsets to my PC. The headsets use an electret microphone requiring a voltage bias of 8V - 16V for power. Each headset plugs into its own instance ...
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0answers
84 views

Connectting intercom audio into sound card

I want to connect the intercom in my apartment to a sound card, both input and output. The voltage of the intercom mic and speaker signals (2 different cables) is 12V while not load is applied. When ...
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2answers
469 views

Got audio mixer circuit with lot of noise. Using two different circuits with same output and noise

I'm trying to do a simple audio mixer. For that I tried 2 different circuits: Circuit 1: which uses LM3900 chip: http://www.theorycircuit.com/audio-mixer-circuit/ Circuit 2: which uses PN2222A ...
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1answer
2k views

How to DIY BaoFeng radio-to-soundcard cable?

I've got a cheopo BaoFeng UV-5RE that I'd like to try as packet radio. I've snipped the plug off of the headset that came with the handheld, soldered it onto some breadboard cables, and did the same ...
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1answer
2k views

High vs Low audio transistor hFE (DC Current Gain). Which is better?

I'd like to preface by saying Rest in Peace my SoundBlasterX's back-panel transistors. What I tried to do, shown in the images below was ground the copper heatsinks I had glued onto the metal side of ...
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2answers
219 views

How does the sound card process different incoming audio signals before outputting to the same speaker simultaneously?

Below is a primitive representation of audio flow in a PC: simulate this circuit – Schematic created using CircuitLab A program executes a code, after many steps in binary/transistor level ...
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0answers
120 views

A question about generating low frequency sine waves by a soundcard

As a part of a bigger experiment I need to control the frequency of a speaker by a PC through a MOSFET amplifier. The rest is someone else will use that speaker output for some mechanical application ...
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1answer
124 views

A very basic question about DAC conversion in a sound card

This is a conceptual question about how a sound card converts digital data to analog. To illustrate this let's say we have constructed a discrete data which represents a sinusoid with particular ...
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1answer
428 views

How can I connect a dynamic microphone to a computer's microphone jack?

I have a generic handheld dynamic microphone and I want to connect it to my laptop for voice chatting. Normally it should connect to an mic amp and then goes to soundcard's line-in jack. But my ...
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3answers
984 views

Attenuate 75W speaker to Line-In

I have a 75W amplifier with a 8ohm speaker connected. I need to record the audio from that output, so i was thinking in using a voltage-divider to condition the signal and record it through the Line-...
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5answers
818 views

Regulating LED brightness using headphone output

My PCs headphone jack (green) outputs a 4Vpp (2V amplitude) sinusoidal signal at 100% output level set in the sound preferences. What kind of circuit would I need to drive a red LED (2.2V forward ...
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3answers
287 views

Raise SNR of pulse signal by passive LC filter

I have a weak pulse signal, rise time 1us, fall time 10us, 0.01 to 200 pulses per second, dead time between pulses is random, along with mostly ‘white’ noise. The system has two goals of extracting ...
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1answer
1k views

Connecting multiple devices and speakers [closed]

I am attempting to connect several devices (Two PC sound cards, CD player, and TV audio out) to two sets of powered speakers. The devices are currently set up using a bunch of 1x3.5mm male -> 2x3.5mm ...
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2answers
932 views

Turn on transistor with output from sound card

I want to turn on a transistor by playing sound through my computer's soundcard. I thought that this simple circuit with a diode to rectify the AC, capacitor to smooth it out, and a transistor to ...
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2answers
1k views

How does a PC sound card be able to detect 433 MHz signals?

I have developed a radio driver that can detect sensor RF packets for a particular protocol, in 433 MHz band using a 433 MHz receiver module like this one and also similar to this one. Before I ...
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1answer
728 views

Circuit to use sound output as a signal generator - design check & choosing values for C and R

I am a beginner in electronics. I got myself a second-hand analog oscilloscope but I don't have a function generator. So, as a first project, I am trying to design a circuit to use any device's sound ...
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1answer
1k views

Weird behavior of 'soundcard' oscilloscope

This is what I did I expected a nice square wave on my soundcard oscilloscope software but I'm getting this What is happening ?
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2answers
561 views

Questions about sound card scope software?

This is a popular software for those people who don't have a real oscilloscope or function generator: https://www.zeitnitz.eu/scope_en If anyone tried it before, would you answer my questions, please?...
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2answers
836 views

Can I play sound from USB, Not from sound card?

I made an FM radio transmitter circuit and it works. It is supplied using a 12 volts transformer. The input of the transmitter is connected to the output of my PC's sound card (just like the way we ...