# Speaker frequency response question (numbers jumbles)

Discussion in 'Archived Threads 2001-2004' started by Troy LaMont, Aug 28, 2001.

1. ### Troy LaMont Supporting Actor

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In getting a handle on what a prospective speaker is capable of, the frequency response of a speaker is often taken into consideration.
I do understand that typically, don't rely on the listed frequency response to judge a speakers capabilities.
So my question is, what are the different rating methods listed when it comes to frequency response;
• Overall Frequency Response 20Hz - 26kHz
• Lower -3dB Limit 32Hz
• Upper -3dB Limit 25kHz
• 35 Hz to 22 kHz ±2 dB, -6 dB at 30Hz
It all seems a little confusing when trying to get a handle on what a speaker 'may' be capable of.
Thanks.
Troy
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2. ### Saurav Cinematographer

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In the electronics and other engineering industries, the frequency response of anything is the range between the two -3dB points. "Overall Frequency Response" is a meaningless marketing term for a range with an undefined cutoff level - in this case, it looks like it's less than -6dB, perhaps it's -10? The only speaker manufacturer I know of who uses +/- 10dB ratings is Bose.
In this case, you can use those three sets of numbers to get some idea of the slope of the speaker's roll-off. Assuming the speaker is near full response (i.e., 0 dB) at, let's say, 45 Hz, you can see that it's down -2dB at 35 Hz, -3dB at 32 Hz, and and undefined number at 20 Hz. Similarly for the high frequency cutoff. The other thing that these numbers tell you is that within the frequency range, the variations are +/- 2dB - in my experience that's fairly respectable, but not too many manufacturers provide this information.
Hope that helps.

3. ### Wayne A. Pflughaupt Moderator Moderator

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Troy,
Of course, specs like this are no guarantee that a speaker is excellent, but they are a good start.
In the case you’ve given us here, the important numbers are the 35Hz to 22kHz ±2dB. These are excellent numbers. The figures below 35Hz are more important than the numbers above 22kHz. It shows the speaker is down only 6dB at 30hz. In short, this speaker has very smooth response, with excellent extension.
Regards,
Wayne A. Pflughaupt
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4. ### Troy LaMont Supporting Actor

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Guys,
Thanks for the info. So I guess the the main numbers to pay attention to is the ± dB range? This would give you the best 'numerical' assessment of what a speaker is capable of.
The examples provided are actually from two different sets of speakers, from different speaker manufacturers.
The first sets specs would be more along the lines of 32 Hz-25 Khz ±3 dB, while the second sets specs are 35 Hz to 22 kHz ±2 dB, -6 dB at 30Hz.
Based on what you guys have stated about the second set (35 Hz to 22 kHz ±2 dB, -6 dB at 30Hz), these speakers are

5. ### Wayne A. Pflughaupt Moderator Moderator

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Troy,
Yes, the speakers are comparable. But again, frequency response is only a starting place when shopping for speakers. For instance, with a little EQ Peavy PA speakers can get flat response, but you wouldn’t want them in your living room.
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Wayne A. Pflughaupt
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6. ### MarkO Second Unit

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I always wondered why after 100 hz on the lil graph most speaker's response drops like a brick, even tho the speaker is ratted at a lower freqency. Is this why so many high end pre/pro's bass managements crossover starts at 100hz?

7. ### Manuel Delaflor Supporting Actor

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Troy
There is another factor to consider, and this is how fast the response decay beyond this -3dB "frontiers". For example you can have two set of speakers rated at -3dB from 30Hz to 20Khz. But for me the important thing is that one of them will roll down to 20Hz at
-12dB and the other at -6dB.
Got the point?
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8. ### Troy LaMont Supporting Actor

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So I guess to sum it up, check out the frequency response, but let you ears (and emotions) do the deciding, right?!
Thanks to everyone.
Troy
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