Frequency of speakers?

[deleted-801488]

Hi, I'm doing a steam fair project and decided to choose https://www.sciencebuddies.org/science- ... se#summary and need assistance with finding the frequency in the first place. I will be looking up the manufacture's numbers for the speakers I have at home and then test to see if the speakers I own from the companies match in frequency. In order to do this, I need to know how to find the frequency. I have a computer and the speakers I will be testing.

[rmarz]

22f0b111a1c24786b72d9250b8c4a428 - I read the summary describing frequency response characteristics noted in your question, but really don't understand the experiment you may be thinking of. Clearly, a perfect speaker will have very linear response over the frequency specified by the manufacturer. You don't describe how you intend to measure the audio output of the speakers you intend to test, nor the method (variable audio oscillator/amplifier?) to drive the speakers. Perhaps I don't understand your experiment very well, maybe you can share more details so we can be of more help. Thanks.

Rick Marz

[deleted-801488]

22f0b111a1c24786b72d9250b8c4a428 - I read the summary describing frequency response characteristics noted in your question, but really don't understand the experiment you may be thinking of. Clearly, a perfect speaker will have very linear response over the frequency specified by the manufacturer. You don't describe how you intend to measure the audio output of the speakers you intend to test, nor the method (variable audio oscillator/amplifier?) to drive the speakers. Perhaps I don't understand your experiment very well, maybe you can share more details so we can be of more help. Thanks.

Rick Marz

Pretty much my experiment is finding the frequency of speakers I have at home, but I go online to look up the manufactures specs to compare. My question is how to measure frequency output at my house. This is exactly what I'm going to be doing "If you have a home stereo system, see if you can look up the frequency response data for the speakers from the manufacturer. Do your own experiments to measure the frequency response. Do your results line up with the manufacturer's claims?"

[rmarz]

22f0b111a1c24786b72d9250b8c4a428 - I think you are starting to understand the complexity of this experiment. You might need these minimum pieces of gear to set up an experiment.

1) An audio oscillator or frequency generator. A smart phone app for a frequency generator might suffice, but you would need to adapt an earphone cord to connect directly to the speakers being tested.

2) An audio receiving device to monitor and measure the audio output coming from the speakers. An oscilloscope would be ideal, an AC voltmeter might suffice. A microphone and amplifier with AV voltmeter might work, and again, a smart phone app for a 'sound meter' might work acceptably.

3) any of these devices may have their own linearity or calibration issues, but at least the use of these devices may provide a "relative'" study of the frequency response of the speakers.

4) Measuring input frequency and magnitude and comparing it to speaker audio output amplitude would create your data set.

You mention the desire to see the manufacturer's claims of the frequency response of a particular speaker. Typically the manufacturer may say 20Hz to 18 KHz with some +/- some decibel variance. I don't think you will find (or even need this info for a useful experiment). Don't worry about verifying the manufacturers claims.

If you can well describe your experiment, even with shortcomings on precision or possibility of certain errors, take and record meaningful data, and finally describe your conclusions, you will have a very acceptable experiment. Good luck, let us know how you do. This is interesting.

Rick Marz

[deleted-801488]

Thank you, I heavily regret my mindset when choosing this experiment as it made me waste a lot of time as the due date is arriving. I have gotten the phone app on my mobile device and also have my speakers in hand. You mentioned not needing to worry about manufacture numbers. If I don't have these numbers then what measurements will I use to calculate the percent error?

[rmarz]

Luke Ogbeni - Your experiment is to evaluate the quality of the frequency response of your speakers. An 'ideal' speaker would have a very flat characteristic, that is, the audio output would perfectly follow the input power over a wide range of frequencies That is why you would measure input power at many sample frequencies and measure sound output at each sample point and compare the two. An interesting experiment, good luck.

Rick Marz