# Loudspeakers What is Frequency Response?

Discussion in 'Sound, Music, and Intercom' started by lieperjp, Dec 4, 2008.

1. ### lieperjpWell-Known Member

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To put it simply, what is frequency response?

I was reading an article in the Nov. 2008 Live Sound about subwoofers and for the subwoofers listed it gave something called

What does that mean?

Note: The +- is supposed to be a plus-minus sign but I couldn't figure out how to type it in Firefox.

2. ### AndrewWebberleyMember

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Frequency Response in speakers is simply what frequency range the speaker can produce. The +- part is the variable amount from speaker to speaker. If they list the frequency response as 100 - 300 hz +-3db then the speaker can produce sounds between 100hz and 300hz but the actual volume/amplitude of these signals may vary by 3db. The db decibel and that is how sound loudness is measured. So you may have a speaker that is a little louder then another or you may have speakers that produce certain frequencies at a louder or softer volume. I hope this helps.

Andrew

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Essentially, the idea is that nothing can produce a perfectly flat output across the audio spectrum. That is to say, it's not possible (or very difficult) to make a device that has the exact same volume at 30 Hz that it does at 100 Hz. Thus, we have the concept of frequency response.

Usually, we will pick a convenient frequency (say, 100 Hz or 1 kHz) and then determine the loudness of the device at other frequencies relative to that baseline frequency. We convert that to decibels, and then make a plot of the frequency v. the amplitude. Generally speaking, better devices have a flatter line across the frequencies they are designed for.

it is worth noting that the better a product, the more likely you are to find a plot (or multiple plots) instead of a line that says "Frequency Response: 20 Hz to 20 kHz, ±3dB" This doesn't tell you much at all - a plot would show you exactly where you have peaks and dips in response. 'Course, for electronic devices you also need to know what the source, input, output, and/or load impedances are too for the frequency response plot to make any sense, but impedance is another topic altogether.

4. ### anonymous381Member

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AKG however has gotten very good at it!!

EDIT: I'm pretty sure they only make headphones

Last edited: Dec 4, 2008

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