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

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1answer
36 views

Get peak voltage from RMS power (Audio amplifier)

I want to calculate the peak voltage output of an audio amplifier when driving at its maximum rated power, a loudspeaker. For example, an amplifier rated at 50W RMS into 8 ohms, driving an 8 ohm ...
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0answers
26 views

Connecting HiFi Amplifier High-Level Out to Subwoofer Low-Level In

I have an oldish Denon 375rd, with 2 zones but no pre-amp nor subwoofer outputs. I just got a Focal Cub 3 without realizing it's more of a Home Cinema subwoofer and it has NO High-Level Input, only ...
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1answer
24 views

How can use MP45DT02 and CS43L22 DAC with STM32F4?

I'm doing an application with MP45DT02 MEMS audio sensor omnidirectional digital microphone. I'd like to use a STM32F4 MCU to control it, but I don't know much about it. Can I take input from the ...
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0answers
51 views

Why does this State-Variable low pass filter overheat when turning up resonance?

I am trying to build an audio-frequency state-variable resonant filter. Power supply is ±15V. The circuit contains three TL072 op-amps and three LM13700 OTAs. It receives audio input from -2.5V to ...
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3answers
105 views

Amplifier design: feedback with unclear poles

When designing a closed loop amplifier for audio the poles of the open-loop transfer function are usually only vaguely known. \$\frac{1}{(s-p_1)(s-p_2)...}\$ These poles can be modeled as \$RC\$ ...
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0answers
65 views

Can this op amp circuit easily be modified to provide differential input?

I have a "noisy ground" problem which seems to be essentially the same as the one described in this old post: Ground loop? Switch mode power supply noise The solution (as provided in the answers to ...
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0answers
52 views

USB Audio Stream to Codec

I have been trying to design a USB Audio Interface with an Atmel SAM3U microcontroller and I think I have hit a wall in my thinking process. As a sidenote, I'm relatively new to the world of ...
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1answer
113 views

What kind of device is this? [closed]

Hi, I found this device lying around somewhere and I have no idea what it is. Can someone help me figure out what it is?
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0answers
62 views

One-shot sound button/trigger for Arduino Sound Player

I've succeeded in making a simple Arduino ATMega328 sound player on my breadboard following this guide. . . http://highlowtech.org/?p=1963 http://playground.arduino.cc/Code/PCMAudio But, here's my ...
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1answer
50 views

Why is the cut summed in a graphic equalizer?

I would think a basic graphic equalizer could function as such: a bank of filters, each with their own connection through a potentiometer to a summer (such as an op-amp summer). However, I've run ...
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2answers
97 views

What is the audio voltage of an android phone?

For a project I am currently working on, I need to use the audio output of an android device. Is there a standard max voltage?
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2answers
55 views

Looking for OP-Amp with good rail to rail performance, 5V to 0V [closed]

There are thousands of OP-Amps on Farnell's website, so I thought asking the stack-exchange community might be a good idea. I am looking for an OP-Amp for use in my project. I currently have an ...
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0answers
20 views

CS42L52 output PCM?

I have an MCU connected to a CS42L52 codec over I2S and am able to input and output sound with no problems. When I pass the input from the codec, through the MCU, and back to the codec for output, ...
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2answers
67 views

Ferrite Bead Current Rating

Could anyone let me know how can I calculate the current rating required for a ferrite bead on speaker path? The speaker impedance is 32 ohms.
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3answers
59 views

How to correctly connect audio plug to LM386?

I'm working on my first circuit which includes LM386 chip and some music. Since I don't have a lot of experience with electronics I need a little help with audio plug. It's the same as that: I know ...
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0answers
14 views

Audio streaming issue with CSR-8670 kit

We are using Source App in "Analogue mode" in which we reached to a point where our kit is able to paired with the mobile device but when we start to play audio in mobile through paired CSR audio ...
2
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1answer
53 views

Integrated audio DSP with free tools?

(Intro here, you can skip this for the actual question) As a hobby project I'm building an audio amplifier. It'll be the amp for my "home theater". I only have a small room so there's no room for 5.1 ...
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0answers
39 views

Connecting Android phone MIC with external speaker

I am trying to generate a sound from my PC and have my Android phone receive this sound through its MIC by the headset plug. I was reading on this topic and this is taken from a web site * To ...
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1answer
50 views

Static in earphones when scrolling with mouse [closed]

Why do I sometimes hear faint static in my headphones when I scroll with my mouse? I have noticed this on multiple(4) computers, with Windows 7 and 8. Does anybody else notice this? It happens when I ...
2
votes
2answers
75 views

QAM's Demodulation

Let me confirm how the demodulation process of QAM is. $$s(t)=I(t)sin(2πft)+Q(t)cos(2πft)$$ Then we have to guess \$I(t)\$ and \$Q(t)\$ in order to know what the said bit formation of the ...
3
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2answers
195 views

How can I simulate a bridged output of a speaker at 8 ohms?

Following on from my previous post on a single 5V rail amplifier, I'm trying to simulate a bridged output op amp set up to drive an 8 0hm load. One of the solutions was: Use a bridge output. This ...
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2answers
88 views

What is the low frequency limit for ferrite cores in audio applications?

I've searched high and low through the ferrite magnetics catalogs and this list for an answer and can't find data on ferrite core permeability below 10kHz. My application is for audio use and I need ...
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3answers
170 views

Alternative to LM386? To drive 8 ohm speaker with 9V circuit

I am getting pretty tired of debugging the LM386 integration into my project! I'm building a drum machine, based around schmnitt trigger oscilators and a white noise generator. I'd post the complete ...
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4answers
718 views

Is the only way to drive a speaker with a positive and negative rail?

I want to create a simple sinusoidal oscillator (Wien-bridge with soft limiting), connected to a high gain amplifier. I don't have much experience with audio, but I'm guessing a speaker needs a ...
2
votes
1answer
73 views

What is the use of dual differential amplifiers in audio applications?

Why do audio amplifiers use dual differential pairs sometimes? Is there a mathematical justification and not just "the joy of symmetry"? Any hints, especially with some math would be of great help. ...
2
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1answer
126 views

Why are audio power supplies center negative?

I see that power supplies for guitar pedals, speakers, etc are always center negative. Is this a conscious design choice, or is it a marketing trap?
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1answer
102 views

Use “real” condenser microphone element instead of electret condenser microphone

Apologies my original question was completely unhelpful, I'm trying to make a USB condenser microphone, and the tutorial I was trying to follow used two electret condenser microphones, which were ...
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0answers
40 views

Preamp circuit LED driver

I was wondering if the this schematic would work in my scenario: My scenario is that I want to play an audio file from my phone, in which the audio file will be played from my phone which will be ...
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1answer
47 views

Audio Precision SNR

I recently checked SNR of the class D Amplifier on board our product. I used AP2722 for amplifier characterization. The SNR displayed by the analyzer as below: -87.85 db below 2.76 dbV reference ...
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2answers
45 views

Optimal headphone impedance

Looking at the data sheet of the MAX4410 headphone driver, lower impedance headphones will get more power. Is this true in general for laptop headphone drivers? especially with regards to 8-32 ohm ...
2
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0answers
47 views

Troubleshooting audio output on Nexys 2 (FPGA)

I've recently purchased the PMOD AMP1 module from digilent for use with my Nexys 2. When I program the demo project and plug headphones or speakers on the headphone output I can hear a barely ...
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2answers
53 views

Latency concerns for a wireless audio mixer?

I want to design an audio mixer that works wirelessly and has a web interface. Here's what I'm generally thinking: One component is a 1/4 inch plug with an amplifying circuit and a WiFi module which ...
1
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1answer
441 views

How To Blink LED's with MOSFET in response to Music?

trying to blink LED's by music. i've done this circuit no problem: Now wish to accomplish the same thing using an N-channel Mosfet. I tried this circuit, and got no blinks. Also no success with ...
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1answer
99 views

Small but powerful speakers [closed]

Why are powerful speakers like above 20w or 80w not small? I have never seen enough in the market which are under 3 inch but of 80W. The opposite is also true, some big speakers are of low wattage. ...
1
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3answers
93 views

Audio FET Buffers and Negative Feedback

I am struggling to come to term with how negative feedback helps widen the scope of input signals coming into FETs (or OpAmps for that matter, but I am using J201 JFETs). I am aware that the largest ...
2
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0answers
47 views

Does use of cermet pots lead to scratching in a DC audio circuit?

I am putting together an audio EQ module that is DC coupled. I have read in many places that carbon pots will scratch due to DC present in the circuit. Do cermet pots exhibit the same behavior? I ...
1
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1answer
78 views

Line-out: why is there no impendance issue when plugging an amp rather than headphones?

Given that the input of an amplifier has very high impedance, while headphones have very low one, why can I plug either one or the other on the audio-out plug of my computer? Even with a degree on ...
0
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1answer
49 views

adding limiter to reduce distortion in audio amp

I got this schematic from adafruit. But at high volumes, it exhibits distortion. A guy from Maxim Integrated referred to include a diode-resistor network(BAV99 and R-100 Ohm) b/w C22/C23 and R8/R9(to ...
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16 views

I2S - Choosing the right SCK frequncy for a DAC

I'm currently working with a DIR9001 SPIDF reciever, which takes a SPIDF signal and converts it into I2S (for feeding into a DAC). The datasheet gives me a bunch of options for selecting the system ...
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2answers
65 views

Binding LM4871 audio amp output to another circuitry with ground referenced input

I using LM4871 as a audio pre-amp in my device. If I let the output to earphones or external speakers then it works great. If I want to loop LM4871 output (pin 5 and 8) back to one of the local audio ...
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0answers
56 views

Best possible specs for a MEMS mic in 2014?

I want to use the best MEMS mic that's on the market today (June 2014) in terms of audio quality. Since I know that "shopping" questions are forbidden, I'll phrase it like this: What are considered ...
1
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2answers
96 views

Signal power and perceived volume

With a couple of friends I am designing a synthesizer on an altera FPGA (cyclone II, the one on the DE2 board). We almost wrapped it up nicely but there's a problem that bugs us. The synth can ...
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0answers
60 views

Using TPA3122 as a headphone amp

So, long story short, I ordered two sample chips from Texas instruments and they inadvertently sent me 25- and were nice enough to let me keep them. I'm still finding uses for them, and it crossed my ...
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2answers
76 views

Main speaker specs to consider

For a 20W amp, what are the determining characters, apart from speaker Impedance and Power rating, that affects a selection. Example Specs - (source - ...
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1answer
81 views

Understanding a circuit diagram

I am trying to use an electret mic with beaglebone. Instead of making a preamp, I am using a locally made 'audio board'. This is the instruction slip that came with it : However, I do not ...
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2answers
78 views

Class D amplifier output signal

I am using this class D amplifier SSM2356 in my design. I am giving same input to the audio input left and right. I play a audio and probe the supply, input audio and the audio output signal (both ...
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2answers
112 views

How is this preamp design?

I'm trying to design a preamp for this electret mic. I kind of pieced this schematic up from something I have found on the web. Does that look ok? I'm going to sample the output with an ADC ...
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0answers
153 views

Reading sound with BeagleBone Black

I have a BeagleBone Black and I need to compare sound on two different microphones. BeagleBone Black does not have audio input, and I believe the audio cape only has a mono microphone input. Is it ...
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1answer
60 views

Prevent Clipping and Hum in class d amplifier [closed]

I got this amp. Now at large volumes, there seems to be clipping. How can I prevent it from happening, rather than never playing at high vol. Can it be done by AGC or Dynamic Range Compression or ...
2
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2answers
76 views

Minimize noise on electromagnet using audio frequencies

I have an electromagnet (coil with about 500 uH inductance and 0.8 Ohm resistance) that I want to drive at 4 kHz with about 3 Amps of current. I want to achieve this with minimum noise and power at ...