9 votes

Is there a mechanical equivalent to a hi/low pass filter (as in electrical engineering)?

In a more general sense, the electrical concepts of inductance, capacitance and resistance are equivalent to mass, spring constant and friction in the mechanical world. Voltage becomes force and ...
  • 6,759
8 votes

Is there a mechanical equivalent to a hi/low pass filter (as in electrical engineering)?

Yes, for sound specifically there is a term called "acoustic impedance" that, just like electrical impedance, is frequency dependent. Acoustic impedance results from the acoustic wave equation, which ...
  • 3,535
8 votes
Accepted

Is active noise cancellation useful in vehicles?

Some reasons why noise reduction in vehicle cabins is not a standard feature, yet: As @Trevor Archibald states, safety is a very good reason. There is still a need to hear some noises from outside ...
  • 9,527
5 votes

Do kids under a certain age not hear the warning beeps that smoke detectors make when they are running out of battery power?

Unless they have hearing loss, young people tend to be able to hear a larger range of sound frequencies than older people, particularly higher frequencies: Some security companies recently began ...
  • 9,527
5 votes

Is there a mechanical equivalent to a hi/low pass filter (as in electrical engineering)?

There are analogs to filters in lots of mechanical systems. In fluid systems prone to pressure spikes perhaps because they use a fixed displacement pump, an accumulator will be used to filter out ...
  • 2,135
4 votes
Accepted

Powering LED light using smartphone headset jack

This is a very interesting question. I would say, yes and no. The headphone jack is not designed for this at all, and you won't get much power out of it. My preliminary research indicates that an ...
  • 211
3 votes
Accepted

Arduino DAC to Speaker

Your understanding of the issues is good. Q1: It's not overkill at all. All of the elements you've mentioned are needed. Q2: The low-pass filter frequency needs to significantly attenuate all ...
3 votes

What type of test signal is appropriate for frequency response analysis of string instruments?

First, can you really actuate white noise? If yes, White noise would probably show many natural frequencies and harmonics. However, make sure the actuation bandwidth is sufficient for your frequency ...
3 votes
Accepted

Why does audio equipment buzz/humm when a long signal cable is used and how do I eliminate it?

The reason for the humming noise is improper grounding. Audio signals are low voltage level AC signals (over simplified). An audio signal could be for example 1V, 1 KHz signal. When there is improper ...
3 votes

Why would a "delayed loudspeaker" be so expensive in the 1970s?

The band was the Grateful Dead and the invention necessary was an analog delay line that was inserted between the main audio mix signal line and the power amps that drove the speaker arrays (which ...
3 votes

Is it possible to measure the "noise level" of an area without using actual microphones which can record actual audio?

How do you define a microphone? Because there many ways to detect mechanical vibrations, but all of them could fit in a more or less relaxed definition of microphone. For example, you could measure ...
2 votes

Acoustical Design considerations for Active Noise Cancellation Project for Air vent

The first big problem is with your speaker placement; the 'anti-noise' speaker should be as close to the 'noise' speaker as possible. Another big problem is with the speakers you are using; they are ...
2 votes

Acoustical Design considerations for Active Noise Cancellation Project for Air vent

I don't think there's enough room in a comment to add all of this, so that's why I'm posting this as an answer. What do you mean when you say, "I have implemented LMS on Labview"? What is LMS? What ...
  • 3,535
2 votes

Microphone angled waterproofing

You could make a water drain trap. Drill a vertical hole that meets the microphone hole somewhere along its length, with a drain hole sloping down for the water to escape. You could then make a step ...
  • 12.5k
2 votes
Accepted

Using the bitrate value on a calculation is causing contradiction, why?

Because the file is compressed. The sample rate and bits per sample are parameters of playback after decompression. The file size is for the compressed format, the amount of data that needs to be ...
  • 6,133
2 votes

Microspeaker enclosure design for headphones

the equations scale linearly for the linear dimensions of enclosures. However, here is why micro-enclosures don't get designed according to the same laws and equations used for full-sized speaker ...
2 votes

Why does audio equipment buzz/humm when a long signal cable is used and how do I eliminate it?

That long audio cable is acting like an aerial. Does it run close to any mains wires - in the wall perhaps? You will be better off getting a quality shielded audio cable as a first step. If that ...
  • 14.2k
2 votes

What causes the hiss from one audio source but not another over long cable?

I will first assume you do not have any of the wires crossed here. It is unlikely that the cause is in the CAT6 cable, but here's how to test this: send the alexa signal (red) thru the cable to the ...
2 votes

Does Bitrate on sound files refer to bit/s or byte/s?

what you are calculating is the uncompressed bitrate. However, MP3 uses lossy compression, typically achieving final sizes of about 10% compared to the uncompressed file (for constant bitrates). ...
  • 22.9k
2 votes

Is it 8 kHz the minimum number of samples per second and can that be written into a sound player?

Can you have a lower sampling rate? Yes. Wll it perfectly reproduce the original sound? No.
  • 14.2k
2 votes

How did this tape recording possibly happen on a technical and logical level?

This is very easy to do if your tape recorder had a recording function called "punch in". This lets you switch from playback straight into record mode without first stopping the tape. So, ...
2 votes

Mackie CR3 bookshelf speakers only play incredibly quietly on max volume

This is a standard issue diagnostic issue. We could send you to an audio equipment SE but diagnosing issues is what I do for a living. You say you have already checked most of these but the order I'd ...
1 vote

Why does audio equipment buzz/humm when a long signal cable is used and how do I eliminate it?

As mentioned the cable is acting like an aerial. A ferrite core to wrap the cable around a couple of times might help. The comm to the charger comm is grounding it with less resistance as the other ...
1 vote
Accepted

How can I calculate the total signal level (noise) of PC fans?

This is a pretty straightforward calculator: https://www.engineeringtoolbox.com/adding-decibel-d_63.html Basically noise level is dictated by your 2 loudest sources, so 50 dB + 40 dB (assuming they ...
  • 2,337
1 vote

How can I calculate the total signal level (noise) of PC fans?

The standard rule of thumb for adding decibels is that doubling the sound power increases the dB reading by +3dB. Using an on-lone calculator for adding dB's, we find that adding two sound sources ...
1 vote

Making my microcontroller transmit audio to any bluetooth headphones/speakers

There are Bluetooth adapters available which will hook into audio system via 3mm jack or optical jack and broadcast the music to your headset. However if you want to receive the music into your phone,...
  • 21.2k
1 vote

Adding an R2R Digital to analog converter inline with TRS connector

Okay, I will go ahead and answer my own question. Since I'll have to deal with an analog signal anyways, coming from the audio output of a mobile device. I'll need an ADC [analog to digital ...
1 vote

Microphone angled waterproofing

Why have the hole perpendicular to the front surface? Angle the hole so that it is slightly uphill when the screen is at the angle as shown. Or, could you fit a membrane on the surface of the ...
  • 14.2k
1 vote

Could a magnetic audio tape recorder/player be made using a vibrating permanent magnet?

Magnetic force microscopy should have sufficient resolution. The principle of operation here is that an external force causes a very small (few micrometers) magnetic probe to vibrate, and then the ...
  • 2,526

Only top scored, non community-wiki answers of a minimum length are eligible