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

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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
59 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 ...
4
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1answer
147 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 ...
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0answers
15 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
42 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
30 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 ...
2
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1answer
53 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
58 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
32 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
55 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 ...
-2
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1answer
33 views

Wire an aux input in place of a broken CD player [closed]

I'm looking at a record player on craigslist (http://sanantonio.craigslist.org/for/4899732512.html) with a broken CD player. As this is the year 2015 no longer own CD's anyway. I was wondering if ...
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2answers
26 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
22 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 ...
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1answer
39 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
109 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 ...
1
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1answer
44 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
39 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
47 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
46 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
29 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
277 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
49 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: ...
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2answers
64 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 ...
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2answers
74 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
26 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
57 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 ...
9
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2answers
381 views

Single supply op-amp audio amplifier

I am trying to create an op-amp amplifier that would work from single 5V supply, and would be able to amplify -100mV to +100mV audio signal to around a 1V peak-peak or so. I've came across this ...
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0answers
17 views

How to transmit audio wirlessly from a non bluetooth device to a bluetooth phone? [migrated]

I want to transmit audio from a device having an earphone jack to an android phone wirelessly. How to accomplish it over Bluetooth. I looked at ED05 Bluetooth board and A2DP, H2DP profiles but could ...
0
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1answer
25 views

iPhone jack remote buttons wiring

I'm trying to emulate via Arduino the volume down button of the remote mounted on iphone earbuds, and I can't find anywhere how that function is achieved; I imagine ...
0
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0answers
32 views

Connect CB Microphone to Smartphone

I'm planning to use an Android smartphone as a realtime voice effects processor with my CB radio. I did a little internet research about the way Android devices detect a connected headset and found ...
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2answers
68 views

Analog circuit to check if an audio signal is present?

On the project I am working on, I have 3 line-level audio signals, and I need to determine on an arduino if a non-silent signal exists on each line and act appropriately (in my case, "unplugging" a ...
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2answers
97 views

I can not receive radio waves using LM386?

I've made two different circuits to receive RF using LM386 but they doesn't work. I've changed the values of C2 and L1 to change the frequency. I've also changed the gain but nothing happens. The ...
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80 views

Is it possible to make a device that will transmit a sound\suppress my neighbour speakers?

Let's say, I've a highly inadequate, impudent neighbor who is listening to music very loudly. I've seen on the Internet that's there's a possibility to transmit your own audio to a neighbor speakers ...
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2answers
57 views

Ground loop noise goes away when heater comes on [closed]

I have a ground loop or something in a stereo wiring. I have 3 stereo's connected all with the same inputs(fanout). One stereo several feet away from the other two has an annoying amount of hum. ...
2
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0answers
48 views

Reducing noise for a TDA8947J amplifier

I have an PC audio amplifier using TDA8947. One 30W subwoofer and two satellites. It produces a lot of background noise and I would like to cut it down a bit. The noise is all in the subwoofer. It ...
1
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1answer
49 views

Mechanical vibrations picked by an audio amplifier (Strange microphone efect when there is no microphone)

I open today a Philips audio system (30W woofer + 20w satellites) because it has a lot of noise. And I have seen something at list triple weird. When I knock into the circuit board with my finger nail ...
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2answers
63 views

Beginning Audio Electronics [duplicate]

I'm 16 and interested in getting into audio electronics so I can make things like mixers and speakers, etc. I currently only have a rudimentary understanding of electrical circuits which extends only ...
3
votes
1answer
83 views

8Khz vs 48Khz audio sampling and noise expectations

I'm messing around with this dac/dsp combo going into my picmx32. Finally I have loopback stable and working cleanly at 48Khz sample rate. This is a little too much data for me though so I want to ...
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0answers
50 views

hijack project microtransformer doesn't work well

I am working on a project that need to get energy harvest from smartphone headset jack.I find hijack project has a solution.the energy harvest circuit of it is below: it use coilcraft transformer ...
0
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1answer
30 views

Little doubt about amplifier current requirement and THD + N

So for this amplifier IC - PAM8403 - which is a 3W + 3W class d, what is the current requirement or in other terms, what will be the load current. I know since this is an audio amplifier, load current ...
2
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1answer
55 views

Modding a Fender princeston chorus, having issues reading this part of the schematic

I am trying to add some wires for the left or right channel of this fender amp, and having trouble understanding the schematic here: There are 2 1/4" phono jacks on the front that are input no 1 ...
0
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0answers
63 views

How does this single-ended to balanced circuit work?

This comes from the sparkfun jamboree bluetooth audio board schematics (https://cdn.sparkfun.com/datasheets/Wireless/Bluetooth/Purpletooth_Jamboree1.pdf) How exactly does this work? With S7 in ...
2
votes
1answer
101 views

Why would an audio circuit output through two caps like this?

I'm studying a circuit that is based on a clone of the Apple Mockingboard from way back when. Being new to EE, the first thing that struck me as odd is why the ...
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2answers
82 views

Noisy record for STMicroelectronics MP45DT02 digital mems microphone

I bought STM32F4DISCOVERY board and I developed a software that records .wav file using MP45DT02 MEMS microphone on this board. .wav files that I record are really good (almost no noise). I designed ...
1
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1answer
54 views

Simple Audio Sampler And Looper

I am seeking to build a small drum pad that can trigger short mp3 files. Here there are a lot of specifications and I don't expect to have everything explained, but any tips on how to go about making ...
0
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2answers
57 views

Send data to an Arduino by using an audio cable

I want to send some Data to my Arduino by using the audio jack of my smartphone/computer. (USB is no option, since my smartphone does not support USB Host mode and I also don't want to go wireless or ...
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2answers
77 views

What does the output waveform from audio source look like?

I understand that every audio waveform will be different but in terms of frequency and amplitude what can I expect? The audio source is an audio jack connected to an Ipod or computer audio jack. What ...
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1answer
123 views

Cost Effective Solution to using PAM8403 as a headphone amp

I've just bought a PAM8403 pre-built circuit board for $1 on eBay, I was going to use it to drive a set of headphones but I neglected to consider that this is a Class D amplifier and will not take ...
0
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2answers
63 views

Need help to vibrate a motor for an original musical instrument

everyone. I am asking you to help me out for making original musical instrument. The goal is to vibrate a small motor by square wave signal witch is generated in a synthesizers in my Mac. Here is ...
1
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1answer
67 views

Mutually exclusive headphone and speaker

I have a device that has only one set of analog audio out signals that are amplified for headphone usage. I want to be able to use these signals to output to a set of speakers OR a headphone jack, but ...