Questions tagged [microphone]

A sensor converting an acoustic signal into an electric one.

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54 views

NPN condensor mic pre-amp really noisy

I have designed a pre-amp and I am having a lot of noise when silent. It seems to be around 70 Hz on my scope, but jumps around. I've tried adding bypass filters on the NPN emitter legs, as well as ...
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3answers
2k views

Why would this microphone only work while touching the volume control?

My son bought this USB microphone for his computer. It only works if you keep your hand on the volume knob. I assume this is a grounding problem. I took it apart. It looks like the copper wire ...
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91 views

How to Feed SIM800L MIC IN

I want to connect 8 Ohms/0.5W Audio output line from an ISD 1820 Voice module to SIM800L MIC IN. I see on both SIM800L MIC IN & ISD1820 Speaker out are not common ground.They have marked SP+ SP-, ...
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1answer
79 views

MEMS microphone different output voltage at the same dB

I am trying to measure noise using the ADMP401 (MEMS) sensor. In the dynamic sound (applause, the sound of hitting the desk, etc.,) a sensor output of + -200mV is obtained. However, for the sound of ...
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32 views

Intercom System

I am trying to make a prototype to test a circuit. It is about am intercom circuit. I have an intercom device with 2 wires, and it supports multiple stations and everybody can talk and hear at the ...
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1answer
57 views

Connecting a preamp to computer

I've made a single transistor preamp for an electret mic. The curcuit is like this: simulate this circuit – Schematic created using CircuitLab I want to use this on a computer. The mic input of ...
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1answer
48 views

Is the 3.5mm jack somehow connected to the phone's transceiver?

I could not find a clear answer to that and it's driving me nuts, because I have a microphone, which when connected to my phone via 3.5mm jack picks up a sort of buzz, as if from wireless inteference. ...
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2answers
98 views

Risk of long-term shorting XLR cable

I'm adding a 'mute switch' into my XLR cable. To mute an XLR cable/Phantom powered microphone you temporarily connect pin 2 and 3 in the cable to short the connection. I have seen plenty of youtube ...
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1answer
40 views

Making a phantom powered power switch (not mute switch) with LED indicator

I want to create an XLR inline power switch (with indicator) so that I can turn my phantom powered microphone on and off as I please! I have found a few guides online that explain how to create a ...
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2answers
108 views

When wiring an electret microphone is using the wire shielding as ground ideal?

Currently with a "single-conductor" shielded wire I have connected the (+) pole of the mic capsule to the wire, and the (-) pole to the shielding strands. I am wondering why the ground wire doesn't ...
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2answers
179 views

Headset microphone is noisy, but touching speaker wires removes the noise

I'm repairing my simple wired headset which is composed of two little speakers and one microphone. The audio and mic jacks are separate. The speakers work fine. But the microphone is very noisy. As I ...
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1answer
42 views

What is a digital common?

I am working with Benthowave BII-7186 Miniature Probe Hydrophone. In its datasheet I have come across the following information about wiring: I am not sure what is Digital Common, and how different ...
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1answer
54 views

Replace microphone signal with an audio signal taken from my phone

From researching on the internet I have learned that microphones output analog voltages and with the help of amplifiers they can store that variating voltages as digital data in case you want to store ...
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1answer
89 views

What kind of microphone is this and how do I use/bias it?

I am designing the mic input for a ham radio chip I bought, a DRA818V. Someone gave me an old Kenwood ham radio mic and said I can use that mic for my circuit. The mic element is shown below: What ...
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0answers
63 views

Audio Loopback Dongle Sanity Check

The same circuit as in Explain “Audio Loopback Dongle"; I wanted to know how it worked. Anything I couldn't figure out I found out via CircuitLab's time analysis: simulate this circuit – ...
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1answer
320 views

Explain “Audio Loopback Dongle”

This AOSP/Develop/Audio page describes the following audio loopback dongle. Can someone explain it? To ensure that the output signal will not overload the microphone input, we cut it down by about ...
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1answer
400 views

How to connect a line-out to mic on Android plug? (CTIA)

I want to connect line-out of a device to the microphone input of an Android phone, a Xiaomi Mi 4X. Then I can record and live stream from the phone. If I simply connect line-out left/right (red/...
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79 views

Can any microphone approach the sensitivity of the Human ear in the same mass/volume? [closed]

I recently dropped a very tiny object onto the floor in a normal room (mass probably low milligrams). I heard it hit the ground. I would like to build a circuit that could "hear" such a small sound ...
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3answers
81 views

Best XLR cable and metal for home use & vocals? [closed]

I am very lost on what the recommended XLR and also the what the recommended type of metal connector is for sound quality as many say completely different things such as Silver being more conductive ...
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2answers
348 views

TL082 electret preamp and LM386 power amp

I have spent the last few days trying to prototype a TL082 electret mic preamp (based on this schematic). I swapped the TL071 in ...
4
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1answer
324 views

Acoustic localization

I apologize if this is not really an EE question, but it seemed most appropriate. I am considering the following application. Object is 3000m far away and emits a sound of 94 dBSPL at 0.5m, I, ...
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1answer
297 views

Microphone with LM386

I am trying to build an audio amplifier circuit based on this design using an LM386 opamp. On the output side (pin5) an Arduino is connected constantly reading out the pin ...
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2answers
131 views

Filters generate output even if they are not connected to any signal and does respond differently to different signal sources

opAmps are fed by +/- 9V. I have two more filters like this one, in total three filters. If I use a signal generator as input signal and observe output via an oscilloscope; all those filters give me ...
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1answer
97 views

Is there a preferable way to amplify the signal from an electret microphone? [duplicate]

I need to amplify the microphone output to some level about 3-4 Vpp without a DC offset. The output voltage will only be sensed (it will pass through a peak detector). So I assume I don't need any ...
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1answer
93 views

Electret microphone signal amplification

What will be the output of these electret microphones? To be able to have a 3-4 Volts peak output, what should be the gain approximately? P.S. : Unfortunately these are not products bought from a ...
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1answer
64 views

Electret microphone weird offset problem

Hi I am trying to amplify my output from electrec (analog microphone) with below design. When I used 1uF capacitor it has -300mV offset, so that I changed capacitor to lower value with trial-error ...
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1answer
74 views

Cannot connect microphone using audio jack

I have a microphone and a female 3.5 mm audio jack. I want to use the jack to get the signal from the microphone for a project with an arduino. To test if the microphone works or not, I'm trying to ...
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0answers
243 views

How to connect Electret Microphone module and OPAMP?

I am trying to build a circuit that gets electret microphone input and maps into 0-1V for utilizing in ADC. The microphone module suggests using such circuitry When I tried that circuit and talked ...
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1answer
116 views

How to record a speaker?

Complete noob here. I don't need a ready to implement solution, pointers on what to read upon and ideas for even simpler projects to gain experience first are perfectly fine. I'm trying to feed both ...
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1answer
1k views

How can I make a phantom power mic popless mute switch?

I want to make a phantom power (PP) mic mute switch with an indicator led powered by PP. I already did it based on the following circuit. It works but, with the led included in the circuit, I get a ...
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2answers
297 views

3.5mm Push to Talk Switch

I am looking to take a 3.5mm microphone line, insert a press button switch (a foot pedal in my use case) between the headset and the computer. I would like the switch to mute the mic connection when ...
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1answer
51 views

Microphone Pre Amp Book? [closed]

I'm wondering if there's a book that discusses resistors, capacitors, inductors, transistors, transformers, impedance, op amps, power supplies, and the general circuitry of a microphone pre amp. Thank ...
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1answer
39 views

polarised condensor microphone

Sir/Madam, Kindly explain how is the following equation derived for the polarised condenser microphone? The output voltage V0 fed from the microphone to the preamplifier will be how is it derived? ...
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2answers
208 views

Why electret microphone with Op Amp circuit cause signal negative half wave to distort

This circuit works quite well with low signal levels, but when the RMS ac signal is appr. 0.8 to 1.0 V (measured on pin #1 of the opamp), the negative half wave of sinusoidal signal is distorted so ...
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2answers
1k views

Adapting two-way radio tactical throat mic (laryngophone) to cell phone or laptop

I've ordered one of these: https://www.amazon.com/gp/product/B074Z1LDY2/, a tactical throat mic (and earpiece speaker) which is intended to be used with Kenwood two-way radios (and other compatible ...
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1answer
205 views

ADC distortion when writing to microSD

I am doing my own project making a basic audio recording device using microcontroller's ADC to get the audio signal from electret microphone and saving data to microSD card. I'm using STM32L476RG ...
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1answer
54 views

Can i bypass the builtin rectifier and directly supply dc to my microphone preamp and reverb board

I currently have this mic preamp and reverb board that accepts 12-0-12 ac: original I have a 24v 10a switching supply and i found a way to create a 12-0-12 dc using this tutorial on youtube Would ...
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2answers
303 views

Electric current in mic

For a typical mic a singer uses in a concert, how much current is generated when the singer sings? The current transmitted from the diaphragm into the wire. What does the following specification tell ...
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0answers
247 views

Convert 3V unbalanced microphone to 48V phantom balanced

I have the following circuit in an existing product, which has a microphone, power switch, LED indicator, and is powered by 2 AA batteries: simulate this circuit – Schematic created using ...
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0answers
96 views

extracting DC from audio signal for biasing

I've been wondering if there is a simple means of extracting a DC signal from an AC+DC signal for the purpose of providing a small DC supply to a CMOS device. Essentially the signal I'm considering ...
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1answer
153 views

(Electret Microphone) Why is input taken from the capacitor?

Why is the input signal taken from the -ve side of the capacitor? I do understand that the resistor has been added for voltage divider. Is this actually for filtering purposes? Or is the capacitor ...
0
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1answer
49 views

Car microphone; very low signal

I would like to use a car microphone for bluetooth communication. The mic is a BMW one: 84316938762. The wiring diagram (TIS) marks the mic's two connectors for the pin 1 and 2: TIS (X18507). ...
0
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1answer
66 views

How can I attach a USB microphone to a Breakout-board using ADC Ports? [closed]

I am almost a total noobie to electrical engineering and I bought a programmable Drone called "PlutoX" from here. I am currently trying to attach a USB microphone like this: to the so called "X-...
0
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1answer
59 views

Bad background noise in audio capture [closed]

I have a microphone attached to a Realtek ALC5640. The circuitry is as below: L9 is Murata BLM15PD121SN1D The noise capture is here. How could I improve the situation and reduce this noise, if ...
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1answer
102 views

LM567 or Custom bandpass filter

I'm using a array of hydrophones to localize an underwater pinger (37.5 kHz and 45 kHz) and I'm thinking of using LM567 tone decoder as a frequency filter. The other option is to design a custom ...
0
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1answer
769 views

Motorola telephone-style handset audio to 3.5mm jack

I retrieved a Motorola Telephone-Style handset wich was in service with a Motorola radio GM380. It is the same as https://shop.motorolasolutions.com/rln4756-telephone-style-handset/product/RLN4756A ...
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1answer
232 views

Why an 8kHz notch on the headset mic input of a Qualcomm WCD9330?

I have here a smartphone which uses a Qualcomm WCD9330 audio codec IC. (Itʼs a Galaxy Note 4.) Iʼve discovered through testing that the headset microphone input exhibits a roughly 10dB notch in its ...
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1answer
282 views

Translating mic sensitivity dBV to dBSPL

In mic datasheets, mic sensitivity is usually expressed in dBV that equates to 94 dB SPL (@1kHz). So if my mic sensitivity -46 dBV equates to 94 dB SPL, does that mean that if I double the signal by ...
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3answers
1k views

Why is the collector feedback bias popular in electret-mic preamp circuits?

I got some simple electret microphone modules and I've been experimenting with audio amplifiers. I googled to find some example circuits, and I found that most of them resemble the circuit above. I ...
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1answer
45 views

SMT electret microhone PCB mounting [closed]

I see a lot of SMT microphones in vendors' lineups. All of them orient normal to the PCB--either up or down. I'm working on a design where the microphone has to point parallel to the PCB. On the ...

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