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

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Classification SVM

I have a problem with Support Vector Machine classification. I have two classes of children (boys and girls). I use a MFCC function for training (for each class I have 24 coefficients, window names ...
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2answers
43 views

Suggestions for a simple microcontroller [on hold]

Please suggest a simple digital solution for an equalizer implementation. I am not looking for any feature heavy DSP based IC, since my application only requires some minor adjustments on the bass and ...
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1answer
51 views

DC offset spike?

A week or so ago, I accidentally damaged one of the speakers of my audio system, most probably because of a loud and high-pitched distortion (noise? - it's basically a "pop" when ...
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1answer
46 views

is it possible to ignore the audio jack? [on hold]

i would like to have a headphone jack with an on/off button, so that the jack will still be connected to the device (computer, phone etc') but the device would ignore it. does such a thing exist? and ...
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1answer
28 views

ASP solution for sound enhancement [on hold]

I built a stereo speaker and to an extent it sounds good. But I noticed, by changing the EQ to "Rock" genre in my MP3 player, the instrument clarity became more clear and vocals were more fuller, ...
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0answers
17 views

Reading Flow Meters from Mic Port

I am attempting to read two hall-effect flow meters through the audio-in (mic) port of an Android device. I want to be able to read both flow meters independently. The audio-in port is a standard ...
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0answers
22 views

How to output audio using an altera DE0 FPGA?

I am working on a project that involves realtime image processing using altera DE0 fpga board. Due to the nature of the project I am also really interested in including audio output. However according ...
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1answer
30 views

In what order should I isolate and attenuate an audio signal?

I have a cheap bluetooth audio module (with no documentation) that outputs a signal greater than line-level. It was probably designed to be connected directly to small speakers, since the ground on ...
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1answer
103 views

Ghosts? Speakers playing sound from Raspberry Pi 2 without being connected [closed]

Yesterday I discovered something really strange: my speakers were influenced by my Raspberry Pi without having the headphone jack plugged in. Well okay, that does not sound very special, since they're ...
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14 views

bluetooth audio transmitter [closed]

Is there a simple bluetooth system that can be attached to Zone 2 Audio out of a home theatre system that will broadcast and automatically connect to multiple headsets or speakers simultaneously and ...
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1answer
31 views

Getting started on Voice recording and play back [closed]

I am looking for those small ICs as in Toys and in water level indicators , that plays a recorded voice. I cut open a toy car that plays a a few lines of song, but I found it COB. So can someone ...
3
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1answer
69 views

LM386 and low-pass filter

First time here, so here I am with an electronic-related question. Please note that altough I have a scientific background, I'm quite new to electronics. Setup I'm trying to build a small audio amp ...
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1answer
34 views

i have a question about a amplifier im working on

the amp is a radioshack mpa250. I hooked it up, and took the top cover off to see how big the transformer and caps were. theres two 80v, 10000uf caps in there, with a 40.5v transformer... i checked ...
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1answer
27 views

How to create a bluetooth module that is both a master and slave?

I'm working on a project that involves having a bluetooth module be a master and slave. I am a dummy when it comes to these things. Basically i need one device like an iPhone to be able to ...
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1answer
19 views

Data transfer to Android USB Digital Audio device

Android 5.0 (API level 21) and above supports a subset of USB audio class 1 (UAC1) features: https://source.android.com/devices/audio/usb.html related links: ...
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2answers
55 views

Real time digital audio frequency changing device

I want to make a device, which takes an AC audio signal like a guitar pickup signal, or piano or what have you as input, and changes the pitch using this function: ...
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0answers
36 views

Connecting an tube output transformer “wrong” to get different primary impedance

I'd like to build a tube amplifier (not for guitar), but have a problem in that it seems I cannot get an output transformer that is proper for the tube (required primary impedance and power rating), ...
3
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2answers
171 views

Creating a loud cracking sound to scare cats away forever and ever

So we have some hardcore cats in our area, recording their glorious conquests with excrement. They don't scare easily. I'll be conducting psychological warfare, they must start associating some form ...
3
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2answers
58 views

How can I protect a DC switch from arcing and sparks?

I have a DC switch that is being used as the main power switch for an audio amplifier project I am working on. The schematic is shown below. (a few things are wrong with that circuit, but have since ...
1
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1answer
55 views

What connector is appropriate for a 500V electrostatic speaker?

A research group just bought an electrostatic speaker that came with a long cable that is meant to be soldered to the speaker wires. However it would be more convenient to have a connector(s) there. ...
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0answers
79 views

Connecting RGB LED light strip to LP3950 color LED driver

I want create color organ controller for use with 12V-24V RGB LED light strip. The LED light color changes need be synchronized to audio signal with both amplitude (beat) and frequency methods (4 ...
1
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2answers
74 views

What is difference between Power-GND vs Pre-GND?

I would like to know the difference between different types of Grounds like Power-GND vs Pre-GND. Are all the grounds not same? Cant we connect the device to any one of these grounds? In my ...
1
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1answer
49 views

What is “Power Supply Pumping”?

I recently came across the term "Power Supply Pumping" in an answer provided to me in return to one of my questions. Although I tried googling I didn't have good luck with it. I would appreciate if ...
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2answers
44 views

Multiple audio inputs driven by one MP3 player output

I wish to make the following design using TPA3122D2N as a DIY project. Is it possible I make two or three of these units and share the MP3 players output among all three inputs on the TPA3122 IC? ...
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2answers
99 views

Need help with a VU meter analog signal

I am making an Arduino VU meter. I need to convert an analog AC audio signal to a varying positive DC signal. I would like the following outputs: 2.5 V output at 0 V input (from VM1); 5 V at maximum ...
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1answer
25 views

Filter Analysis using Audio Analyzer

I have a RC low pass and ferrite bead cap filter combination on my circuit board. I am trying to use Audio Analyzer U8903 to analyze the gain response of the filter. I see quite different result in ...
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1answer
75 views

Question about MCU's, and Audio Manipulation

Ok, so I've been doing some research trying to find something like an audio MCU\DSP with a built in audio filter; for instance, something that I could manipulate audio with to get a final filtered ...
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1answer
157 views

Custom WAVE file results in different sound profile than created

My problem is as following: I'm trying to use my sound card to produce a custom repeating wave pattern which I will use in some laboratory test setup. My curve is based on a combination of a couple ...
0
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0answers
25 views

Phone audio jack IR transmitter and receiver

Note: I'm quite new to electronics so I apologize for any dumb questions. Hi, I'm trying to make an infrared transciever module for my smartphone using it's audio jack. I'd like to be able to record ...
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2answers
65 views

Change AC signal frequency without changing the voltage

I have a non constant -/+1 Volts to -/+7 Volts AC audio signal. I want to design a device that takes this input signal, doubles the frequency, without changing the voltage. So, the output voltage is ...
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1answer
38 views

Does using multiple speakers degrade quality?

I have an amp and 4 speakers. I want to "daisy chain" the speakers together like so: I'm trying to figure out if doing series and/or parallel connections in the diagram above will degrade the sound ...
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1answer
64 views

What is Transient Intermodulation Distortion?

I've looked at Op-amp slew rate over frequency How it is possible to make bad audio amp? Which op-amp for audio? as well as several papers about the topic but although I may get the basis of what ...
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1answer
68 views

Audio amplifier coupling issue

I keep getting oscillation / uncontrollable noise with the following circuit. My input is a balanced audio signal which goes through a TL082 op amp configured as a differential amp. The output of ...
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0answers
35 views

How can I build a comparator for AC?

This simple scheme to compare Vin1 and Vin2 does work for DC current, but how do I build a comparator for AC current? In fact I would like to compare the RMS values. The purpose of the comparator ...
2
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1answer
72 views

Filter noise from a high voltage DC-DC converter

After finding a couple of triodes lying around I decided to build a valve preamp. I've built a simple boost converter based on a 555 timer to generate anode voltage. The circuit is powered from a ...
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2answers
29 views

Stepping-down DC voltage (at low current) in the presence of an audio circuit

I'm trying to add a bluetooth audio receiver to an old 12V battery-powered boombox. The receiver board takes 5V and shouldn't draw much current, but I'm trying to understand which type of DC-DC ...
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0answers
27 views

Piezo contact mic with single core audio cable

Is it possible to create a contact mic with single core cable? If so what are the solder joints I need to make to connect to a piezo? This is a picture of the cable I will be using: Instructions ...
0
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1answer
40 views

Connect ground of system A to 1v6 of system B?

I have an embedded system powered by a 3.7V LiPo battery that will be connected to an iPod's headphone out cable. The embedded system will perform some DSP on the iPod's audio out signal and use ...
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3answers
132 views

Using a 1.5V battery to increase the voltage from a headphone jack so it can switch a transistor at lower volumes

I recently built a circuit using a 2N3904 BJT transistor with the hopes that when connected to a headphone jack, it would light a LED whenever an audio signal was passed through. However, I found ...
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1answer
48 views

Ballpark achievable switching frequency for 100mW D-class amplifier

The background for this question is a Master level university group project, we're designing a class D sigma delta modulated amplifier which is part of a MIDI synthesizer on a large FPGA. We're ...
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2answers
42 views

Converting headphone signals into MP3 using Arduino

For my project, I am looking for a way to take headphone audio signals (from TVs and other appliances), convert them into MP3 and send them over WiFi to a remote device (PC or other) using Arduino UNO ...
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0answers
50 views

using a sycnrhonous motor to drive the voice cone in a speaker

It is possible to consider any arbitrary signal as a continuous function of phase and amplitude. In particular, a digitized audio recording (assuming Nyquist was satisfied) can be transformed into a ...
1
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1answer
65 views

home audio: How much current flows through my speaker amplifier's output?

In a recent project I used relays to electronically control a multi-room speaker selector. I wired these relays in parallel with the physical switches in the box. When I was designing it, I wasn't ...
0
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1answer
33 views

Question about Audio signal trace layout (TLV320AIC3204)

I am using the TLV320AIC3204 in an audio project. The part is a stereo audio codec from TI. I'm curious about how the traces are to be laid out. With other chips such as the AD1939, you need to ...
4
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2answers
321 views

Phase shift and its importance in audio amplifiers

I've just begun building a bass (20-200Hz) class D amplifier and already ran into some problems. The audio source is a car radio with 1V p-p signal. I firstly feed that sigal through a band-pass ...
0
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1answer
52 views

Matching an amplifier to speakers and subwoofer [closed]

I've got a couple of old Bose speakers and bass and I'm looking to wire them with an amplifier so I can use them with a computers sound card. The speakers' manual can be found here. For the speakers: ...
1
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2answers
90 views

Amplify speaker with 9v battery and one transistor

I started electronics recently and I'm trying to make the most basic mp3 amplifier. I try to amplify the music from my phone to the speaker. My phone already amplifies the sound when I connect it ...
0
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2answers
89 views

unbalanced audio - shielding and ground loop for 2 ch

I have a 3 conductor wire that are all wrapped in a foil shield with wire conductor, for a total of 4 wires. I am connecting the 3 inside wires to audio left, right, and ground. This is an unbalanced ...
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0answers
28 views

Increase tone(?) of audio signal

I have a TV digital cable receiver of which audio output I want to connect to an amplifier. Now, I don't know wether there is a problem in amplifier or receiver, but the sound played when its ...
0
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1answer
68 views

Modular mixing table with balanced internal bus: is this a proper way to do it? [closed]

TL; DR: Is the schematic below seem like a proper way of building a mixing console with differential internal bus? I always wanted to have a mixing console but I want to do it the maker way: build ...