This tag is for questions about designing electronics for measuring, processing, and amplifying audio signals. Questions about debugging or repairing consumer audio players and speaker setups will be closed as off-topic.
1
vote
3answers
46 views
How do I amplify a dc voltage that is too weak to trigger the base in a transistor?
I'm trying to take the voltage output from a 3.5mm audio jack and have it light up an LED according to it's voltage. I was going to attach the left audio cable to the base of a 2222n transistor which ...
2
votes
1answer
73 views
Are these pcb layouts good?
I'm working on an USB audio interface; the board has an analog section, with amplifiers and filters for the input and the output signals, a digital section, with the DAC, ADC, and the microcontroller ...
1
vote
0answers
33 views
Split any headphone with remote control and mic into Mic TRS+ Headphone TRS+USB
The main question is in the title.
So I bought a headphone mic Y splitter yeasterday, and the right headphone output didn't work. I took it apart and tried to solder it to the headphone jack with no ...
3
votes
4answers
265 views
Why are high end audio connections gold?
Silver has a lower resistivity than gold and is cheaper, so why are high end audio components gold plated?
3
votes
1answer
54 views
Vinyl player emulation on Arduino
Say, you have an arduino uno + audio shield, a speaker and a jog-wheel (or mouse scroll-wheel).
And you want to play some audio-file tied to the movement of the wheel, just like you move vinyl disc.
...
-2
votes
0answers
35 views
Digital Audio Filter: Delay, Echo, and Pitch Conversion [closed]
I'm using dsPIC Starter Kit (DM330011).
And I want to put those three stuff as a main functions.
Delay: when you speak on Microphone to record it and play it through speakers, hear your voice in 2 ...
-1
votes
0answers
36 views
Problem with impedance matching on DIY 4 pole 3.5mm audio splitter
I built an audio 4 connector 3.5mm splitter. The goal is to play a sound clip through a phone's mic input across a call, while recording the same sound clip on the computer. I used the TRRS ...
2
votes
2answers
100 views
Bipolar Op Amp w/ Near Zero Offset?
My understanding is that if source resistance is low, a bipolar op amp has 10dB less noise than a JFET. I prefer the JFET op amps because the input offset is so low that you can eliminate coupling ...
0
votes
2answers
81 views
Reducing noise in an audio amplifer using opamp
I am trying to make an audio amplfier using an opamp for a project. It works kind of okay but the only issue is there seems to be a lot of noise in the output of a 0.5 watt speaker. I have tried ...
-3
votes
0answers
81 views
Coupling a current generator to a very high impedance [closed]
I hacked my car radio, cause I've lost code. So I decided to enjoy the TDA7560 as a final stage. Actually I made an hack you can see here
It works well, but I have a few doubts. I have an input ...
-3
votes
0answers
58 views
Audio Filtering [closed]
I have some doubts about how to implement a solution for the app that I explain below:
I want to filter specific audio sounds (truck, trumpet...) with an arduino and a microphone (amplifier + ...
0
votes
2answers
72 views
RC circuit and tone
Can I generate a tone on an 8-ohm speaker using a 5VDC power source, resistor and capacitor? For example if I want to generate a 440 Hz tone, could I use resistor capacitor values such that RC = ...
-2
votes
0answers
61 views
algorithm required for audio and video seperation [closed]
can anyone give me an algorithm to separate audio and video from a video signal having both audio and video part. I want to implement it using filters and make it work on matlab . Also any kind of ...
1
vote
1answer
79 views
mp3 player shield make noise
I'm using mp3 player shield from sparkfun and Arduino UNO. Everything is ok, I formated my samsung micro sd cards with FAT, I converted mp3 files with ffmpeg, I load the examples file and modified ...
1
vote
1answer
51 views
How to make a cable to record cockpit intercom?
I would like to record the cockpit intercom with my iPhone and a recording app. I do not know much about impedance matching (other than what it is).
I would like to make a cable that plugs into ...
-2
votes
0answers
50 views
Can anyone identify the source of this EM interference? [closed]
In my apartment (3rd floor), I've noticed that several electrical items with speakers emit a lot of noise when placed in certain areas of a room. This seems to occur most at the side nearest the ...
-1
votes
1answer
106 views
How to match audio impedance? [closed]
I have an audio source designed for a 600ohm speaker. I would like to use this audio source with the speaker it is designed for as well as record the source using the standard mic-in on a GoPro. How ...
-4
votes
0answers
56 views
Connecting Samsung LED Digital Audio Out to Creative 4.1 speakers [closed]
I have currently a Samsung - UA40D5900VR LED TV which i need to connect my Creative Cambridge 4.1 computer speaker
My TV has only Digital Audio OUT (optical) whereas my speaker has 3.5 mm male ...
-6
votes
2answers
125 views
Simple amplifier Cuircuit [closed]
I am new in electrical transistors. My project is to make a 1 watt audio amplifier. Can anyone provide a best amplifier circuit using darlington pair and 2N3904 transistor. i searched google. So ...
0
votes
3answers
67 views
Microphones disturbed by capacitance
I've used several KE 4-211-2 Sennheiser microphones to assemble a device for acoustic signal analysis. They are connected to a National Instruments data acquisition device with ~1 m long cable and ...
0
votes
2answers
79 views
Car CD reader mod to read mp3 disc
I read the article: Modding a CD ROM drive to read DVDs. In my car trunk I have a 6-CD changer. However, it can read only audio CDs. Would it be possible to change the laser head (or adjust it) to add ...
-1
votes
1answer
69 views
Talking Tom Hardware [closed]
We want to make Talking Tom doll.
Talking Tom is an IPhone App. When you speak to it, it echoes your voice with voice of child.
Is there any ready scheme to construct it.
I mean scheme from mic to ...
-3
votes
1answer
54 views
Best way to Interface with PC/MAC/iDevices/Smartphones [closed]
What do you think is the best way to communicate a hardware with PC, MACs, iDevices and Smartphones (with Android, Windows Mobile, etc.) ?
We need to make a voice chat (like VOIP) and also exchange ...
-4
votes
0answers
58 views
How to replace mains transformer on AV receiver? [closed]
I've been told an AV receiver (Denon AVR-1312) requires a new mains transformer and was wondering if it was an easy enough task to complete myself?
I have experience working as an IT technician and ...
1
vote
5answers
215 views
MOSFET or Transistor for using as switch for audio signals
I was wondering which component is better for using as voltage controlled switch for audio signals (e.g. music signal from mp3 player). Should I use MOSFETs or transistors? The max rail voltage is ...
-4
votes
0answers
72 views
Advice needed: Develop a bluetooth device at the size of finger ring [closed]
I have a small requirement. I like to amplify the microphone signal of a smartphone (android/iphone/windows phone) using a bluetooth device that can be worn on finger as ring. The idea is not to loose ...
0
votes
1answer
74 views
Replacing a condenser mic with a MEMS mic
I'm working on a black-box piece of electronics which has a cylindrical "condenser microphone" with a main body diameter of 4 mm and height of 1.5 mm
I want to replace the condenser mic (black box) ...
2
votes
2answers
120 views
I want to connect mic to audio output in arduino?
My knowledge in electronics is poor.
I want to output audio stream from mic to audio
And I use following code in Arduino
...
2
votes
1answer
181 views
Best way to go about biasing a Class B audio amplifier?
I am trying to bias the class be audio amplifier in the provided pdf. None of the resistor values are correct so the bjts are unbiased. What is the best way to go about starting to bias this?
...
2
votes
2answers
137 views
Designing parallel RLC band-stop filter in series with load from f0, gain, Q parameters
I've been trying to design a band-stop filter for my headphones to cut back on excessive highs and to provide a more flat frequency response.
With a software EQ and lots of tries, I managed to arrive ...
3
votes
2answers
252 views
LM386 audio amplifier not amplifying
This is my first attempt at making a really simple audio amplifier. The schematics are below:-
First I tried connecting the circuit to a 9V battery. (Multimeter reads around 8.3 Volts, which is in ...
1
vote
2answers
136 views
Shorting ground and left (or right) of 3.5mm audio jack from the computer
I'm trying to build a shutter release for my Canon SLR that is controlled from the computer. Since the shutter release is simply shorting two points on the headphone jack together, is there a way to ...
1
vote
1answer
81 views
voice activated circuit with static burst [closed]
I would like to build a circuit that will activate when it detects a voice and when the voice stops to make a static burst sound like a voice activated radio.
What I am trying to do is make a voice ...
3
votes
1answer
96 views
How to interpret microcontroller ADC module on datasheet? Datasheet syntax question
I am currently working an Atmel micro controller, the EVK1104S, which has the UC32 Data Sheet. We have actually planted this chip on a custom PCB and are in the process of writing more firmware.
...
1
vote
2answers
56 views
How to reduce an audio signal to proper input level?
I'm working with an audio ADC that supports a max audio input of 500mVRMS before it will start clipping. This is sufficient for lots of equipment that does a 1VPP/.35mVRMS line level, but I'm finding ...
2
votes
1answer
94 views
Audio 3.5 mm jack unique hardware key for iOS/Android
Here is the situation. Let's say there is a set of small devices supplied with an audio 3.5 mm jack. Each of these devices represent sort of a unique hardware key value (say just a number or a ...
-2
votes
1answer
86 views
replacing plug on headset with volume control
I have a pretty expensive set of philips headphones with a volume control on the lead that lost sound in one ear, I couldn't fix it and keep the original plug.
Having removed it, I'm at a loss as to ...
0
votes
2answers
129 views
How to detect line level audio signal?
I'm planning to build an automatic switch box for line inputs to my speakers. The switching itself seems fairly straightforward (a pair of de/multiplexers), but I don't know how to detect the audio ...
1
vote
1answer
75 views
Can I convert audio signals from an iphone to electrical signals to control another device?
I wish to design a mobile app that will allow me to touch parts of the screen, generate a music tone that will be converted to an electrical signal to move part of a toy. By touching different parts ...
3
votes
3answers
331 views
How to get fundamental frequency of a signal using autocorrelation?
I am trying to get the fundamental frequency of a signal that only has a single pitch. I coded out the autocorrelation function using FFT and already got the autocorrelation result. Unfortunately, I ...
1
vote
1answer
149 views
What makes the buzzing sound when touching an audio line?
I recently built an audio amplifier based on the LM386. When I touch one of the input signals with my finger, I can hear a buzzing sound on the output. I checked with the oscilloscope, and there ...
-2
votes
1answer
131 views
Easiest Way to Split Audio [closed]
I'm looking for the easiest way to split audio, and I couldn't find a splitter ic. I'm using an msgeq7 that combines the two channels, and I like to have a splitter before its combined so that I can ...
0
votes
0answers
44 views
I want a gsm module that could be attached with a mic and could transmit the voice to my mobile .. is that possible?
I'm making a project so that I place it somewhere and when I call it I could hear what's going there .. so I want a gsm module that could be attached with a mic and could transmit the voice to my ...
1
vote
4answers
159 views
Smallest circuit to make a sound
I'm looking for the smallest circuit to make some noise. This sound has to be constant and annoying, it's intended for the alarm on a timing device. Any ideas?
The circuit will be triggered with a ...
1
vote
4answers
154 views
Headphones impedance and the SPL
The headphones A has an impedance of 32 Ohms.
The headphones B has an impedance of 250 Ohms.
Both of the headphones are similar by size.
Is it right that the headphones B will play quieter by ...
0
votes
2answers
58 views
Dual closed v.s. Dual open audio jack?
I've been looking at getting some 3.5 mm audio jacks for a project I'm working on and these seem to be the best: http://www.switchcraft.com/productsummary.aspx?Parent=529 The problem I'm having is ...
0
votes
2answers
481 views
Connect speaker output to microphone input
What exactly is the difference between a microphone signal and a speaker signal?
I want to make a simple cable to connect a PC speaker output to a microphone input. Does anyone have a good idea or ...
-3
votes
1answer
53 views
Power supply for speakers [closed]
I have two big speakers with only bare wires for input and a small alarm clock with a low voltage output. I was wondering how I would supply more power to the speakers (there are two of them)? I was ...
0
votes
1answer
241 views
Running small external speaker via 3.5mm connection
In short the question is: how can I get the audio from the 3.5mm port of my Raspberry Pi board to play through a small external speaker? Space is a concern in this project I will only have a few ...
1
vote
1answer
139 views
Build an Audio Toggle Box
I want to build a small box with two audio inputs and two audio outputs, with two switches to control the current input/output. Something like this: http://www.youtube.com/watch?v=mQzLnt0_-zU
I've ...
