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59 Threads found on edaboard.com: Microphone Noise
Hi, general answers: * use low noise microphone * use low noise opamps (single stage as long as it does not limit upper signal range) * select parts for low noise (Rs = low value, metal film, Cs = foil, clean power supply = filters...) * use bandpass filters to focus on the frequency range you want. * use low pass filter (...)
Hi can anyone pls explain to me what equivalent input referred noise is. I found this "A microphone converts acoustical energy to electrical energy. microphones have some level of electrical noise at their output. This noise may have contributions from random diaphragm movement, thermal (...)
The same concept is also applied to the microphone wrapped in parabolic dishes that are able to hear weak audible sources from far away, and with the advantage of being less subjected to the surrounding noise.
If the microphone can hear the speaker then you will have acoustical feedback howling. Start with the microphone. Is it an electret type that has a Jfet inside and it needs to be powered or is it a dynamic type with a coil and magnet like a small speaker? The mic needs a low noise preamp. An LM386 is not low noise and is not (...)
There is a large common mode noise generated with floating SMPS that can be problematic for unbalanced sensitive circuits. e.g. external microphone inputs on laptops. Although primary side grounding reduces conducted noise getting back into the line, there is always a coupling capacitance from primary to secondary coil. When no secondary (...)
I'm an expert in falling down but not sky diving. I have experienced similar problems with mobile ham radio on a motorcycle where the engine and road noise operated the vox circuit. The best solution is vox with a throat microphone, one that sits inside a loose fitting elastic collar. It goes under clothing so the wind rush doesn't reach it and bei
" Arduino type microphones ", Surely an Aduino is a microprocessor and has nothing to do with microphones. If you use an Electret type mic (Google "electret"), with a BC548 pre-amp (gain X 10) then any OP amp with a gain of 500X. You will get volts of good audio. To measure its amplitude, it has to be turned into DC and displayed on some device. I
Your attachments are almost completely hidden since they have faint green text to their links. Please post the actual documents HERE. You show a fairly noisy video buffer amplifier with no voltage gain, not a low noise microphone preamp with plenty of voltage gain. You did not describe the noise caused by the circuit. Low frequency hum or (...)
Hello, I would like to connect audio signal from pc sound card to SIM900 GSM module. I am using simple breakout board from Itead studio, I connected the grounds together and signal form sound card to board input. Only thing that I can hear is noise. If I connect microphone I am able to hear sound. Can somebody help me connect sound to [URL="ftp://i
Hi All, I need some advice if possible on how to make the first investigations on a system for noise cancellation/ noise removal. My plan is to place a speaker and a microphone (standard speaker/mike, low cost, non callibrated type) in a room, connect it to a PC audiocard and test if it can attenuate the sound level in the room, being (...)
Hello everyone, I'm using dspic33fj128gp802 to background noise cancellation project. What i did was i'm taking the input from a microphone(headphone mic) as my input(In) and I'm giving my desire input by delaying some miliseconds then i have built a neural network using weights and updating weights. I tried this using simulink in matlab and it
I am working on a project to take an input signal from a microphone and turn on leds depending on the noise intensity. This is my first time using this microprocessor and I was wondering if anyone knew of a good sample code I could reference for this. Any help would be appreciated
hey friends, i'm doing noise suppression and communication project. what i basically doing is I'm going take the speech from the microphone that in headphone. and i have another mic and i'm taking background noise from that. Then i'm giving that noise and voice to dsPIC30f4011. i want know how i detect sound coming from the (...)
When dealing with very weak signals, e.g. in a microphone preamp, using a low noise transistor helps to minimize the noise added to the signal. noise in audio signals sounds like hiss - it's what you hear from an FM radio when it's tuned between stations (or to a very weak station).
Hi All, I am new around here. I using frost beam former matlab code as part of phased tool box. I have conducted an experiment with microphone array of 8, spacing of 3cm with noise and signal . The steering direction is 0 degrees . The noise is 90 degrees to the array. Due to the fact
i need a miniature microphone my application. going to use along with two miniature speakers in a ear probe. the self noise should be less than 5dB. please recommend any product with this specification I dont know why, but I have feeling that you are student with some big exams in near future. :grin:
1)Should the Mic be powered in order to work or not?? 2)With 10K resistor and 9V,the mic can only draw 1mA of it enough for it to work?? Both times, clearly yes. 0.5 mA is a typical current consumption. The mic doesn't draw any current Obviously, the schematic refers to an electrete microphone with b
You need a noise cancelling mic on phone, -external hands-free mic/earbuds with noise cancelling mic (double sided) is best bet. Test for quality. cheapest one I found just now..
If I understand your intention right, I don't expect, that mixing/adding the microphone signals from multiple rooms and locations serves the purpose. It will reduce overall signal-to-noise ratio by a considerable factor and possibly causing failure of a system, that works well with a single microphone. For reliable operation, you would (...)
try a new microphone. You may have a break in the ground shield wiring.
You may be aware that you can play audio directly into a computer. Some computers have a built-in microphone. However it's possible to pick up computer noise at the same time. Better to use a plug-in mic, webcam, etc. There are a variety of sound recording programs that do this. Some freeware, some priced. (I use a free program called Audac
Hi, I'm new to the site, so hello. This is what I want to build. A set of earmuff style hearing protectors (used with firearms) that has a very small, simple amplifier which attaches to an external microphone and passes voice communication. The only unique thing would be that there needs to be a circuit which will clip gunfire. The idea is
If would possible attach another microphone at another card, could record just the noise, and then subtract one from other : (Voice+noise)-(noise)=(Voice). +++
Hi, I haven't work with audio amplifiers and I need help. I need to connect a microphone to an audio amplifier (using cable), but the distance between the microphone and the amplifier is 200 meters long. On such a long distance the signal will probably attenuate and fail. Now I guess I need any preamplifier, any IC maybe.... Please help me abou
If you amplify the signal you capture with the microphone, you'll amplify the background audio as well as the baby voice. Any noise generated by the following electronic circuitry would make a smaller contribution to the signal to noise ratio however. I think what you want to do is some selective filtering with a bandpass, and maybe a (...)
Hi jonase, Can you please clarify how you are connected the output to the PC? Are you connecting the output direct to the Sound Card's input? If yes then to which input, MIC or LINE input? If you are connecting this to MIC input, you will get excessive and abnormal noise, as the MIC input has already ECM (Electret Condenser microphone) preamp built
You are getting microphony (even there is no microphone involved). PCB layout and quality of some components can generate this phenomenon. Use only SMD components and short layout connections to minimize stray capacitance and inductance. V_tune tracks shall be short and far away or shielded from other signal lines, especially the reference oscillat
And the most important thing, try to change the electret microphone... :grin:
"mic". Did you mean microphone? Jeez, I remember a day when hams would craft their own hardware from bailing wire and spit, and communicate half way around the world. Nowadays, they do not even know what 60 Hz hum noise is. A brave new world?
I don't think this will be an easy project, you want to compare two analog sound sources but even the slightest pitch change or ambient noise in the microphone or audio level will be detected as different sound, even the slightest time difference will trigger the circuit. This can probably be done in the digital domain but it would need very stron
Hello, Does anyone know how to apply adaptive filter to filter/cancel noise coming from microphone/speech signal?
No it does NOT require a preamp stage. But the only problem which i'm facing uptil now is that as soon as the microphone is attached it gets noisy. Any solution for the noise??? Best Regards JD
Hi I am working on conventional frequency domain beamforming for linear microphone receive array. I have simulated 32 channels array data using white Gaussian noise with proper delays corresponding to target at 45 degree emitting 20KHz tonal. I beamformed this data to make 32 beams time series data. To calculate array gain (or beamformer gain
HI, I'm doing a project of standalone recording system with capability of noise reduction. microphone array is under consideration. Now the problem is: 1, limited by power consumption and processing ability, 4 or 8 mics is chosen. In order to simplify the schematics, what audio codec should be chosen? 2, some interfaces, such as USB, displ
keep your microphone shielded, use shielded cable from microphone to opamp. hock
Is there some way to send the microphone signal back to the op amp as a balanced signal? Then if RF leaks onto the microphone signal traces, a simple 200 pF cap across the balanced like will short it out WITHOUT needing a good RF ground point to act on it. You could experiment with balanced capacitors in parallel, and additional capacitors in shu
hi I'm currently working on a project for multi-channel speech enhancement techniques. I've decided to work on microphone Array using Delay-and-Sum Beamforming technique follow-up by adaptive noise cancelling. I've chosen to used MATLAB for the simulation. I have read lots of stuffs on these things and I believe I know the important stuffs. Howe
A wireless microphone is useless without a matching receiver. A good one uses FM at a UHF frequency. dB is a ratio of levels and you don't say what levels you want. Signal to noise ratio? Lifetime of the microphone or lifetime of its battery?
I need December 2000 issue of QST magazine, pages 38-39, for more information and construction notes on a "noise Canceling with Electret Condenser microphones". I'm designing a desktop power microphone to my noise HAM base station. 73, Fernando - Call sign PU2PLL
hi i am using INA163 as microphone amplifier for a 5 ohms symetrical microphone. when the mic is un plugged and power is on it give too much noise. i tried to place resistors at inputs with ground but of no use ., when i place a capacitor across the inputs the noise is gone . can anyone tell me the reason
waqas5304, I see 2 potential causes. When the microphone is unplugged, the IA provides a very high impedance to the outside world 60 Megohms), making it very susceptible to capacitively coupled noise pickup. You can solve this problem by connecting resistors from both differential inputs to signal ground. These ristors can be high compared to t
First of all, I must admit that my knowledge on opamp is very limited. Would someone pls advise what are the functions of IC1A and IC1B in the circuit? How do we relate the sound -> microphone ->
As a start, instead of dealing with the complexity of a microphone feeding a transformer which feeds an amp, why not say that any complex network can be modeled with a voltage source and a series resistance? If you say this, then you could analyze a simple voltage divider circuit, which is what power transfer is after all. Next, if you want a
Probably you need a system similar to biomedical systems. You need a microphone instead of electrodes and follow it up with preamp. This must be followed by filters to filter out unwanted frequency components. For this you need to know the exact frequency pattern of the termites. Finally you need a simple event detector like a comparator.
Hi, Need to convert my electrect PC desk microphone into a directional electrect PC desk microphone in order to reduce pickup of enviroment noise like PC PSU and or PC CPU fan, street noise and so on. If possible with automatic level control (compressor/limiter). This mic will be used in a HAM 80m SSB station. (...)
Hi all, I need a schematic of a MFJ-655 hamProAudio Equalizer / Conditioner like desktop mic. It must not have graphic equalizer, universal microphone interfacing, impedance matching, level control and even a low noise preamp, this is all easy to implement but the rest ... Downward Expansion noise gate, clean Compressor and smooth (...)
Hey everyone, I'm new to this forum. I am working with a group of Virginia Tech EE undergraduate students doing our senior project. We are designing a digital controller for noise canceling headphones. We have a pair of headphones equipped with an internal microphone. We've done initial testing of our system, and designed our controller. The tra
You question is vague. Quality and pattern of microphone, eg directional microphone to reduce pickup of background noise. Quality of codec. Bit rate
I am looking for references on how to calculate SNR, THD?.. for audio applications. For example, if one wants to find the SNR of a condenser microphone what does he/she consider as noise? Does noise include the distortion caused by the non-linearity of the condenser or is noise the floor when no input is applied. I am asking (...)
Mic - do you mean microphone? When talking about audio equipment, "line level" usually means 700mV RMS for 0 dB level. A microphone outputs a much smaller signal, usually a few millivolts.