Questions tagged [audio]
Questions about designing electronics for measuring, processing, and amplifying audio signals.
3,281
questions
-2
votes
0
answers
60
views
Audio amplifier for a physics experiment, how do I make it? [closed]
The experiment includes a mic taking in sound(2KHz-4KHz) and sending it to a DSO. I need an audio amplifier circuit in between that to amplify the signal so it would be visible properly. The ...
1
vote
1
answer
54
views
Coupling/decoupling power supplies: how? [closed]
I'm adding a hi-Z adapter to a solid-state amplifier that is powered from the mains through a transformer and regulator. The hi-Z adapter is powered by 24 volts DC, so i need an external power supply ...
- 113
0
votes
1
answer
44
views
Audio Codec Input/Output Channel Stages
I am planning to build a PCB for a Eurorack Modular Synthesizer, incorporating an STM32 for DSP and a bidirectional Audio Codec like the TLV320AIC3104 to handle the ADC/DAC.
Eurorack audio signals ...
- 1
0
votes
2
answers
71
views
How can I record with this old fashioned mono microphone? [closed]
I have this microphone that comes with a 3.5mm mono jack connector.
When I plug it in to my laptop or my phone it won't work, and I believe the "mono" part is the problem. What do I need to ...
- 103
3
votes
2
answers
374
views
How do you choose an audio isolation transformer for a microphone?
I found a few SE Q/A's for audio transformer characterization, but they neither address calculating the impedance match, nor consider signal loss for weak audio sources (like those from a microphone).
...
- 2,088
2
votes
5
answers
435
views
Do audio impedance mismatches cause reflection (ie, 8-Ohm output to 20kOhm input) ? Does it matter?
I understand that audio source⇒input impedance mismatches are normal, and this answer provides a good reason as to why. However, having worked with RF more than audio, mismatches cause reflection that ...
- 2,088
0
votes
2
answers
55
views
Why does 9.7Vrms == 27 Vpp? I thought it was 9.7/0.707 == 13.72!
At first, I thought this calculator was wrong, because I have always used an RMS to peak-to-peak conversion as \$ V_{RMS} = \frac{V_{pp}\sqrt{2}}{2}\$:
https://benchmarkmedia.com/blogs/calculators/...
- 2,088
3
votes
2
answers
369
views
What type of cap would you use to block DC on a microphone-level audio line (unbalanced)?
I need to block a DC voltage on a microphone line, and a bit of research shows that MLCC is a bad idea because they can mechanically ring from vibration.
Question:
What type(s) of capacitor could be ...
- 2,088
0
votes
2
answers
86
views
What is the maximum dBu I can send into a microphone input in this schematic?
The schematic below is from the Icom 9700 radio service manual (page 80). I would like to feed this input from a mixer board's ALT-3/4 outputs, and I want to avoid blowing the TS462 microphone preamp ...
- 2,088
1
vote
0
answers
68
views
Bipolar 15 V DC from 9 V DC
I’m looking to get a regulated ±15 V DC @100mA minimum from a 9 V DC source. It’s for an audio circuit, so it needs to have a switching frequency well above audio range, and it needs to have a small ...
- 11
0
votes
1
answer
52
views
How can I make an adapter wiring for a TRRS microphone to TRS?
I'm making a sound level meter using a Raspberry Pi as part of my thesis. My professor has given me a TRRS microphone to work with.
I tried to make the TRRS microphone work with the Raspberry Pi ...
8
votes
7
answers
2k
views
What is the reason for using decibels to measure sound?
If the decibel represents a gain ratio, why do we use it in sound measurements?
Yes, since we have an input signal in audio amplifier circuits, we can understand the behavior of this system according ...
- 377
0
votes
2
answers
30
views
Measuring voltage from the aux cable signal
I wanted to make a bjt amplifier circuit to get used to analog circuit design. My plan was to use an AUX cable connected to my phone. I cut the cable and stripped the 3 wires inside. I wanted to see ...
- 377
2
votes
2
answers
96
views
What is the function of the inductor in this Bluetooth audio module?
I found the circuit below for a Bluetooth sudio module that included a 100 mH inductor in series and then a 10 uF capacitor in parallel to the power input.
Image source: Iranian electronics seller ...
- 43
0
votes
0
answers
66
views
Looking for feedback on audio schematic [closed]
I'm making an mp3 player and I'm looking for feedback on the audio side. It takes an i2s input from an esp32(not in this sheet), and outputs to a headphone jack. This is my first audio project (...
- 11
0
votes
0
answers
22
views
Audio project converting TSH-4 headset to 3.5 mm audio jack
I've been trying to connect this TSH4 headset to a 3.5 mm audio jack. The headset has kind of a weird setup, with Mono audio + and - being the top pins (I don't know which is which, but the polarity ...
1
vote
0
answers
68
views
Making audio signals imitate USB flash drives [closed]
If there is a USB port designed for USB flash drives that plays the audio files in that drive when it is connected --such as the ones commonly found in cars-- is there any practical way to turn an ...
- 43
0
votes
1
answer
107
views
Modifying TI schematic to learn more about amplifiers
Let me start off by saying that I'm a complete beginner. I've watched some videos on amplifiers and read about them but it's hard for me to analyze circuits that don't match exactly to the examples I ...
- 1
4
votes
3
answers
477
views
Audio engineering: amplifying two different sources
I've started a small project to renovate/rebuild an old record player for my wife. I have a degree in Electrical Engineering, but it's been almost 15 years since I last had to project/build a circuit, ...
1
vote
0
answers
79
views
Can an audio isolation transformer between a preamplifier and an amplifier cause the amplifier's fuse to blow? [closed]
I'm building a microphone preamplifier. I was having problems with hum (intermittent ground hum when touching the case) and decided to try adding an audio isolation transformer (600 ohm : 600 ohm) ...
- 111
1
vote
2
answers
61
views
Inline volume control for analog audio signals with push buttons [closed]
I want to build something to control the amplitude of analog audio signals between the source (line level analog audio output already extracted and decoded from an HDMI source) and the AMPs. In ...
- 21
1
vote
0
answers
64
views
PCB digital sound input and output
I've designed a simple 3-band equalizer circuit. I've used 3.5 mm audio input connected with computer via 3.5 mm audio jack for input, and basic small speaker for output.
In all my references, many ...
- 31
7
votes
3
answers
514
views
Audio amplifier for school project
For a school project, we have to explain this design of a audio amplifier. We have only been able to understand to parts marked with colored rectangles.
The design comes from the book audio power ...
- 79
1
vote
1
answer
36
views
Identify and substitute f1404zs
I need help understanding which chip I need to buy.
First, I hope this is the correct community; if not, I apologize.
My intention is to repair a Mark Levinson 86280-0w690 audio amplifier, inside ...
- 113
1
vote
0
answers
65
views
How to generate a 50-100 Hz 12 Vac sine wave for audio tone from 5 VDC (PB0 pin) atmega164p microcontroller [closed]
I have programmed to ATmega 164P to make PBO high when PC1 is low. In programming, I'm adding other peripherals as well.
But I am facing one issue regarding generating a tone. I have drawn low pass ...
- 11
0
votes
1
answer
46
views
How to replace microjack on stereo earplugs with microphone [closed]
I broke a microjack connector. It is attached to a set of stereo earplugs with built in microphone. I know how to solder, but I am not sure how to find the correct replacement plug and how to identify ...
- 103
-1
votes
2
answers
65
views
Boost or buck audio input to minimum and maximum levels
Similar to Simple circuit to boost line-level audio
Background:
Some songs start out really quiet - Queen is notorious for this - and then eventually ramp up to passable audio levels. To hear them, ...
- 1
0
votes
5
answers
97
views
How does one add a volume control to this circuit?
My uneducated guess is to add a potentiometer at R6. Can anyone confirm?
Image courtesy : amplifiercircuit.net
-1
votes
2
answers
84
views
How to modify frequency of an analog signal [closed]
I want to create my own pcb. First step is to design my circuit. I thought about a voice modifier.
So, in the breadboard I should put:
a microphone (an electrostatic electret microphone)
followed by ...
- 139
0
votes
1
answer
33
views
switchable summing audio mixer volume troubles
Consider this audio mixer. There are 3 sources that may play any kind of audio (the sine generators are just illustrative). You can switch any of them to either of 2 outputs using the SPDT switches.
I ...
0
votes
1
answer
76
views
Mains hum in TDA7265-based active loudspeaker
The old pair of M-Audio Studiophile AV40 active speakers (one box containing all the amplifier parts and the second is just a passive box) I have have developed a clear low-frequency hum. This hum is ...
- 1
0
votes
1
answer
40
views
Best practices for combining dual mono to stereo? [closed]
I have two old-style telephone pickup coils, each of which has a 3.5mm mono (TS) male output. I made a simple adapter that just runs together the grounds from both inputs and connects each positive to ...
- 1
0
votes
0
answers
124
views
Audio amplifier cutting off and clicking PAM8304
I have designed a PCB with a PAM8304 Mono Class D Audio Amplifier and MAX1708 5v step converter to drive a 4 ohm speaker. The device will be battery powered with 3.3v battery hence the step up ...
- 1
1
vote
2
answers
61
views
Synchronizing multiple I2S codecs on stm32f405
I am designing an audio device that requires two CODECs to be connected to the MCU - two stereo outputs, two stereo inputs. When working with a single codec, no problems with synchronization occur ...
- 1,109
0
votes
1
answer
59
views
what is the source of this noise when recording to raspberry pi using USB soundcard
I connect aux out from my laptop to USB soundcard mic in and use arecord to record audio. But I am getting noise even recording at CD quality. The nature of the noise is really strange as it seems to ...
- 376
0
votes
2
answers
55
views
Can the impedance of the source affect the response of a high-pass filter?
Having a simple RC high-pass filter, can a high signal impedance change the cutoff frequency response? Or more practically, should a resistor before the capacitor be included in the calculation for ...
- 53
1
vote
1
answer
88
views
Audio visualizer: What can I improve in this circuit?
Being a beginner in electronics, I embarked on designing and building a sound visualizer, turning bass, mid, and high frequencies into red, green, and blue light in an RGB LED strip.
I designed the ...
- 169
0
votes
0
answers
69
views
Noise in audio amplifiers when touching the smartphone touchscreen as an audio source
While observing the audio output of my smartphone on the oscilloscope, I noticed a signal being generated when I touch the touchscreen. This signal is around 500Hz and appears in groups of 3 peaks, ...
- 53
0
votes
0
answers
50
views
How do you diagnose a fault with a tweeter?
I have a Pioneer XPRS 10 at work that isn't producing any high frequencies; the 10" woofer working fine, but the 1.75" tweeter is not producing any sound at all. It's a 50W, 8 ohm tweeter. I ...
- 101
0
votes
0
answers
75
views
PAM8403 weird clicking / banging noise
I'm using an ESP32, a PCM5102, and a PAM8403 to output a 3.5mm Audio Jack output.
In my circuit, I'm sending the Audio Signal via I2S to the PCM5102, where a quieter output can be picked up. If the ...
- 1
0
votes
3
answers
122
views
Why is there a greater lag in Bluetooth headphones compared to wired?
The Usual Answers and Responses:
Encoding, Compression, and Buffering
The typical answer to this on the internet is because Bluetooth headphones require the conversion of one form of data information ...
- 111
18
votes
2
answers
4k
views
What is the purpose of these fat copper coils wrapped around … something?
Dissecting 20-year-old outdoor speakers (SpeakerCraft OE8 One), found this electronics board inside. I recognize the capacitors, but what are the big custom coils of copper wire, and what is their ...
- 293
0
votes
0
answers
30
views
Radio mic and speaker as camera mic input
I want to add radio comms to in car action camera audio. I am a total amateur in analog circuits. I understand that i can't just feed headphone out and mic into camera. That will trip PTT (Push-to-...
-1
votes
2
answers
88
views
Why can I hear a radio station when probing with oscilloscope? [duplicate]
I assembled this on a breadboard:
and am hearing a faint buzzing sound...
My first question is, what could be causing this sound? It does not go away if I connect VIN to ground. With or without VIN ...
- 129
0
votes
1
answer
61
views
CB style PTT Mics to USB circuit
I need to design a circuit that takes the input from 2 different CB style (4-pin) push-to-talk microphones and pipes them out to USB. CB mics I have confirmed use regular XLR balanced level output. ...
1
vote
2
answers
86
views
Disabling microphone when secondary one is connected
I'd like to add a 3.5 mm female jack to this circuit so that I can add a better external microphone while keeping the internal one for convenience. What would the circuit look like?
Putting both ...
- 11
0
votes
1
answer
78
views
TRS headphone output socket that may be used with a TS mono jack: how to prevent short to ground?
I'm using a TPA6132 headphone amplifier connected to a stereo (TRS) output socket. In my application, the output will usually be used as a line output, and only occasionally with headphones. The audio ...
0
votes
0
answers
73
views
Automatically Vary LFO Speed Resistance Value
I have a basic tone generator circuit with LFO speed controlled by a 50K pot (variable resistor). I would like this resistance to fall (or rise, but I guess fall might be easier) after the circuit has ...
- 1
0
votes
2
answers
107
views
Help with identifying a problem with an electrect microphone amplifier circuit
I have been trying to make a USB microphone from a JLI-2555BXZ3-GP microphone capsule. This is my specific pre-amp design where V1 represents the electrect microphone. The JLI doesn't have an internal ...
- 3
0
votes
1
answer
41
views
Can I connect two speakers to a mono analog input Class-D audio amplifier
I am using LM4670SD/NOPB in my design. The chip supply voltage is 5 V. My question can I connect two speakers to this amplifier as shown below. If yes what are the things to be taken care.
- 2,593