Questions tagged [audio]

Questions about designing electronics for measuring, processing, and amplifying audio signals.

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3answers
93 views

Send 200 Hz signal over 200 meters in realtime

I have a RC car with a G-Force sensor. The data is converted to an audio signal with frequencies between 0 and 200 Hz. I would need to send this audio to me. The requirements for this are: low ...
-1
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1answer
36 views

PLC Audio Transceiver

So the idea of my project is to simply pass through an audio signal which is recorded using a microphone and then transmit it to the power line and on the receiver part the audio will be played by a ...
1
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3answers
50 views

Speed up or slow down motor of cassette recorder using a potentiometer

Background: There is a cassette recorder (RadioShack CTR-80A) and its owner would like to have the ability to speed up and slow down the motor to record and play the sound in a distorted way. We've ...
0
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1answer
75 views

Reducing the number of expensive capacitors in an audio opamp circuit

I'm designing a guitar effect (simple booster) which uses a CD4053 cmos switch as outlined here (http://www.geofex.com/Article_Folders/cd4053/cd4053.htm) As you can see from the second diagram, RG ...
1
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3answers
84 views

How to properly convert a balanced (line level) audio signal to unbalanced?

I want to connect a balanced line output of a pro grade mixer to a consumer grade power amp that only accepts unbalanced RCA aux in connectors. The mixer has balanced TRS (tip-ring-sleeve) 1/4 inch ...
0
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1answer
66 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 ...
0
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1answer
53 views

How to analyze a dB graph?

The following chart represents almost 5 hours of input received by a sonometer (BENETECH GM1356) at each second in an apartment room. How can I find the answers to the following questions from this ...
1
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2answers
106 views

Changing Voltages in a Circuit?

I am in the final stages of building a fully analog synthesizer. Instead of using +10V, GND and -10V, could I switch these voltages to +20V, +10V, and GND to save weight, bulk, and size of a power ...
1
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0answers
35 views

MCU wake-up for low power consumption system

I´m checking the possibility of designing a MCU system with low power consumption, thus I´m looking for a energy efficient wake-up method. The MCU will be woken up by another device in the same room. ...
0
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0answers
29 views

How to control microphone-speaker connection between two SIM800Ls with a GPIO terminal?

There is a device consisting of two SimCom SIM800L quad-band GSM/GPRS modules and controlled by an MCU, presumably ESP8266. The idea is to let the first SIM800L call one person, the second SIM800L ...
0
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1answer
59 views

How much power is needed to run these speakers?

I have couple of loudspeakers. Each is rated for: RMS Power 60 watts Power 75 watts vc Imp 16 Ohms I am going to build an audio amp for those but not sure how much power is needed. I'm concerned ...
0
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1answer
49 views

XS-3868 module stops noise for 5 seconds, how to make it longer

I've made a bluetooth audio receiver using XS-3868 module (using this diagram) and connected a TP4056 charger module and a lithium-ion battery too. Everything works fine. When the charger module is ...
0
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0answers
42 views

Can I directly connect microphone to speaker of two SIM800Ls

There are two SimCom SIM800L quad-band GSM/GPRS modules. I would like to make some kind of call relay, such that SIM #1 accepts incoming call, then SIM #2 executes outgoing call, and once both ...
3
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3answers
6k views

Audio mixer design

I have a few questions about the mixer design in the schematic below: What purpose do the 22pf capacitors serve? Can I ommit the 1k line out resistor? Is it OK if I use the hot pin of a XLR as input? ...
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0answers
30 views

Music distortion from a Bluetooth board at high volume levels

I have a Drok Bluetooth audio amplifier board that comprised of a TPA3116 audio amplifier, a JL Bluetooth receiver and processing IC and a couple of RLC circuits. I've noticed that when I turn up the ...
1
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0answers
35 views

IC Protector in AV Receiver (ICP-N15)

I'm fixing a Denon AVR-788 AV receiver that won't boot but would turn on with the light in front blinking red. Naturally, I looked to the Service Manual (link goes to schematic) and started following ...
0
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2answers
56 views

Identify whether PCB 1/4" audio jacks are balanced or unbalanced

I have a Fostex 2016 line mixer and was trying to see in the manual (https://www.fostexinternational.com/docs/tech_support/manuals.shtml) whether the 1/4" inputs and outputs are balanced (TRS) or ...
0
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1answer
29 views

Electronic Circuit to Voltage control pan of stereo audio? (Modular Synth)

I'm considering making a Modular Synth module which would pan and modulate a stereo signal. So an electronic circuit to pan the audio from right to left, even allow audio signals crossing over, Left ...
0
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2answers
64 views

What are the pins on this jack connector?

I've bought a PJ-3053 audio jack connector. I purchased it under the impression that it would have a microphone connection, but when I put in a TRRS jack, take a multimeter and measure connections, ...
0
votes
1answer
57 views

Doorbell hack - remote unlock door

We need to use the audio output of a wireless doorbell to trigger a stable DC voltage which is going to keep switched a 3.3V DC relay as long as the audio output is present. The relay is supposed to ...
0
votes
1answer
57 views

Lower than expected power consumption from speaker drivers

I'm using two Visatron FRS 5X-8 Speakers in a project. The amplifier being used is a Dayton KAB-215. Powering the whole thing from my power supply at 12V, I see a current draw of ~50 mA even at full ...
1
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0answers
23 views

Diagnosing USB Power bank shut-off on load application

I'm trying to create a small bluetooth boombox-style speaker, but am having trouble powering the device from a USB battery bank. Fundamental Problem: The power bank "shuts off" as soon as the load is ...
1
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5answers
95 views

emitter follower oscillation cured by adding base input resistor?

I made a simple emitter follower headphone amp using fairly high speed BJT- 2SC5994. Vcc 16V R1- 10K R2- 40k RE- 100 load - 300 ohm After powering up there it was clear there was serious issue, ...
1
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2answers
95 views

Why did my meter read 6 volts dc in the speaker output of a car radio?

While probing a "live" car stereo pins, I also probed the speaker output pins but left the meter in dc volts mode and got a reading of 6v, wich I think is odd, as I asume the output should be ...
3
votes
1answer
209 views

Is volume controlled through a potentiometer?

Eletronics newbie here. I am building my first prototype (using an Arduino) that includes a volume knob. I want to know if volume is controlled by a potentiometer because I saw this video and it got ...
0
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0answers
35 views

feasibility of transmitting uncompressed 16-bit PCM audio through bluetooth

I wonder about the feasibility of this idea, and whether this is something worth doing more research on. I am trying to send 16-bit 16 kHz single channel microphone audio via bluetooth, from one ...
2
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1answer
252 views

Metal enclosure grounding for audio project

Fellow engineers, For various reasons I picked extruded aluminium enclosure for my current audio related project. All exposed metal connector chassis are connected to earth, which then goes to ground ...
0
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1answer
95 views

Is it possible to make a ±3.3 power supply from 9V battery?

I am trying to make a little audio amplifier with a ±3.3V power supply I and would like to power it with a 9V battery. Is there a solution to this? simulate this circuit – Schematic created ...
1
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4answers
174 views

Is it possible to sweep 20 Hz to 20 kHz with one potentiometer?

I'm designing a resonant filter based on a state variable filter topology with sweepable frequency and variable resonance. The filter is designed to sweep from roughly 20 Hz up to 20 kHz (50 kohm ...
1
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1answer
80 views

Miller compensation capacitor sizing

How can I size the circled capacitor in order to get rid of the peaking? Is there some formula? Cheers
0
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0answers
34 views

How to transmit the data from the buffer filled with ADC values through DMA on STM32F7

I am currently trying to a sample a signal between 25-40kHz with three microphones to calculate the time difference. I'm having difficulites understanding what to do after the ADC is activated and ...
0
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2answers
50 views

Removing the load of an AC signal to a DC signal

simulate this circuit – Schematic created using CircuitLab I built this circuit to visualize music with LED's using a full-bridge rectifier I got from a vacuum(meant for 120VAC to 120VDC, with ...
0
votes
1answer
96 views

Negative loop gain?

I was dimensioning the CE capacitor. To do that I was looking at some formulas seen in class. The formula (freq_C=1/(2*piReqC)) involves the knowledge of the loop gain (open loop gain*beta). It ...
1
vote
1answer
75 views

Why is total harmonic distortion defined in the following manner?

So the total harmonic distortion is defined as $$THD = \sqrt{\frac{V_{2}^2 + V_{3}^2 + V_{4}^2...+V_{n}^2}{V_{1}^2}}$$ which means Total harmonic distortion is defined as the square root of the ...
0
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2answers
64 views

Understanding purpose of a resistor in reference schematic TIDU034

Gents, I'm analyzing this schematic, but do not understand couple of things. I would be grateful if someone could explain in detail these questions: 1) R6 - shunt? What's the purpose of it? Under ...
0
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2answers
79 views

Noise on stereo summing circuit from LED's

I've been a tinkerer and hobbyist for 20 years now, but mostly in software. I've done my fair share of simple soldering (replaced controller ports on an original Xbox with actual USB ports, for ...
0
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0answers
25 views

What does “Power Off OOL” AT command mean for a Bluetooth module?

I am reading the datasheet for the OVC3860 Bluetooth module and one of the AT commands is 4.50 Power Off OOL #VX. The description from page 21 of the datasheet is below. [] What does OOL mean in ...
0
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1answer
36 views

Is it possible to make a “Sony CFS-201” cassette player/radio output sound from an external source?

I have an old 1989 (bought new well into the 1990s) "Sony CFS-201" cassette player/radio with a broken cassette mechanism. I'm trying to use it as a "dumb speaker" by hooking up an audio cable from my ...
1
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1answer
117 views

Amplifier memory distortion application

I've found an article about memory distortion issues in audio analog amplifiers. Available for free here. The author uses in the last configuration a CFP differential input with a cascode of FET ...
0
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1answer
54 views

Shifting an audio signal from 0 - 4V to -2 - 2V

I'd like to transmit an audio signal over a digital radio and I figured out I'd need an op-amp in an inverting configuration on the transmitting side to turn a -2V to 2V signal into a 0-4V one. That ...
0
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0answers
64 views

0-5V Audio Signal with TL082

I am working on an Arduino project that requires me to be able to handle audio input from a 1/4" input jack, and it needs to be powered with just one 9V DC input. Since the Arduino cannot process ...
9
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1answer
1k views

How does this transistor (pre-)amplifier work?

The following circuit is part of a larger circuit and processes analog audio. The input comes from the top-right and the output is the rightmost terminal of the pot, which then feeds into a ...
5
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3answers
1k views

Hobbyist: Is this a reasonable design for an audio amplifier? (very sketchy design)

I have always wanted to design and build my own audio amplifier. Is the following a reasonable design? The input stage takes in line level signals (say, up to +/-3 V, but typically more like 0.3 - 0....
0
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2answers
77 views

simple LM386 amplifier noise

I tried to make an audio amp based on LM386 but the output is noisy when the audio is playing. Here is my circuit schematic I built on a solderless protoboard: simulate this circuit – Schematic ...
0
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0answers
43 views

Wireless Audio Transmission with NRF24L01

:) I have been planning to do a project on transmitting audio through arduino using NRF24L01 RF Modules at the same time sending data commands. I am really a beginner in terms of audio circuits so I ...
2
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0answers
127 views

Simple MM Phono Preamp Design

I'v found myself in need of a new preamp for my turntable (the one built into my power-amp went out with a bang and tripped the breaker!). I'm using a moving magnet type cartridge with output around ...
0
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0answers
36 views

“Anti-Pop” Circuit For Guitar Pedals

I want to add resistors to my guitar pedal circuit to remove any popping noise when switching the pedal on and off (actually on and to bypass). Found an article about that, but the values for ...
0
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0answers
187 views

Lowpass Audio Filter on FPGA

I am trying to establish a low-pass filter to Audio Demo code of Nexys A7 board. I have implemented a filter however I hear just a noise. If you share your time, I will be happy. I have added the ...
1
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0answers
46 views

Hi-Z input mixing circuit for Guitar

I am creating a guitar pedal. I want to mix together 3 sources: Coming from electric guitar (or through another guitar pedal) Coming from filtered PWM (for the purpose of generating sinusoidal signal)...
3
votes
2answers
193 views

What is the purpose of this AND gate in an audio amplifier

I am analyzing the below audio amplifier circuit (from 4D Systems) and I am trying to figure out, what is the purpose of the positive AND gate (SN74LVC1G08) which connects to the audio input signal? ...

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