Speaker Response beyond Rated Freq Range

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avtar2008

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I was just playing a few 20hz-20khz test tone to test response of my center channel (https://rbhsound.com/sv661c.php) and thought of playing a 10hz test tone to see the response and to my surprise, I could see the woofer cone moving. My center channel have rated freq of "55Hz-20kHz (±3dB)" and I was not expecting it to response 10hz frequency.

So, I want to ask:
1. does all speaker respond to freq beyond their rated frequency?
2. if above is true, what is significance of rated freq on product specs page.

My testing setup:
1. Source : Youtube on macbook pro(chrome)
2. Connection : HDMI
3. AVR : Denon 3600h
4. Speaker : RBH SV661C

It will good if other users can also share their test result if their speaker responds to freq below 20hz or outside the rated freq band.
 

fLUX

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I was just playing a few 20hz-20khz test tone to test response of my center channel (https://rbhsound.com/sv661c.php) and thought of playing a 10hz test tone to see the response and to my surprise, I could see the woofer cone moving. My center channel have rated freq of "55Hz-20kHz (±3dB)" and I was not expecting it to response 10hz frequency.

So, I want to ask:
1. does all speaker respond to freq beyond their rated frequency?
2. if above is true, what is significance of rated freq on product specs page.

My testing setup:
1. Source : Youtube on macbook pro(chrome)
2. Connection : HDMI
3. AVR : Denon 3600h
4. Speaker : RBH SV661C

It will good if other users can also share their test result if their speaker responds to freq below 20hz or outside the rated freq band.

Hi,

I believe you would have only seen the cone move but not have heard any output. The rated frequency are usually at a particular db range , which means they perform within the acceptable limits in that frequency range. If I take the example of a good sub rated at say 20 hz, it would still give some faint output below rated frequency (in case of conservative ratings , it might give a decent output too below rated frequency range)
 

avtar2008

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I believe you would have only seen the cone move but not have heard any output
Yes correct, but I think we can't hear 10hz. All we can feel the air moving by drivers.

If I take the example of a good sub rated at say 20 hz, it would still give some faint output below rated frequency
I went through this article and this states that speakers are not supposed to give output freq range.

So, I was curious to know if response beyond rated freq range is common across all speakers? If no, what are criteria for mentioned specs.
 

fLUX

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Yes correct, but I think we can't hear 10hz. All we can feel the air moving by drivers.


I went through this article and this states that speakers are not supposed to give output freq range.

So, I was curious to know if response beyond rated freq range is common across all speakers? If no, what are criteria for mentioned specs.

Yup i was not referring to exactly the 10hz but for frequencies outside the specs.

I believe the criteria for reporting varies across the countries (read somewhere that 8 ohm 2ch driven ratings are mandatory across US/EU for the AVR/amplifiers), the manufacturers are usually conservative in their ratings as
i) Its always better to underquote and overperform rather than the reverse. If your speakers are rated at 40hz and they go down comfortable to 35hz as well you will be happy with the fact
ii) To prevent any consumer complaints & cases due to specs being not on par with what is stated.

If the driver is not capable of handling the frequency input at all then its a different matter, but otherwise any conservatively rated speaker should be able to go a few hz below the actual rated frequencies.
 

alpha1

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I was just playing a few 20hz-20khz test tone to test response of my center channel (https://rbhsound.com/sv661c.php) and thought of playing a 10hz test tone to see the response and to my surprise, I could see the woofer cone moving. My center channel have rated freq of "55Hz-20kHz (±3dB)" and I was not expecting it to response 10hz frequency.

So, I want to ask:
1. does all speaker respond to freq beyond their rated frequency?
2. if above is true, what is significance of rated freq on product specs page.
A speaker is a stationary electric motor. So it will oscillate as long as there is an alternating electric current - whatsoever may be the frequency.
So that means it will move at 0.1 Hz, as well as at 100000 Hz - subject to mechanical limitations.

When someone mentions 55Hz-20kHz (±3dB), it means that the speaker will reproduce these frequencies within an error band of 6dB.
So when your speaker is fed with a 90dB 100Hz signal, ideally it should produce 90 dBsound of 100 Hz but your speaker may produce anything between 87 and 93 dB. Similarly at 1000 Hz, it may produce some other decibel levels but within the 6 dB band.

For the frequencies above and below this range, there is no guarantee how many dBs will the speaker produce and therefore never mentioned in the speaker specs.
 

avtar2008

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A speaker is a stationary electric motor. So it will oscillate as long as there is an alternating electric current - whatsoever may be the frequency.
So that means it will move at 0.1 Hz, as well as at 100000 Hz - subject to mechanical limitations.

When someone mentions 55Hz-20kHz (±3dB), it means that the speaker will reproduce these frequencies within an error band of 6dB.
So when your speaker is fed with a 90dB 100Hz signal, ideally it should produce 90 dBsound of 100 Hz but your speaker may produce anything between 87 and 93 dB. Similarly at 1000 Hz, it may produce some other decibel levels but within the 6 dB band.

For the frequencies above and below this range, there is no guarantee how many dBs will the speaker produce and therefore never mentioned in the speaker specs.
Yup, i think this would be correct explanation for rated frequencies.

Just wonder how common it is in speakers to perform outside the rated frequencies.
 

RajithKumar

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It may function ,only the rated spl may not be there.
Any measurements available .
IMO,It's better avoid to do such test as a precaution,to avoid any damage.
Still if u want to check ,do it at low volumes.
 

avtar2008

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It may function ,only the rated spl may not be there.
Any measurements available .
IMO,It's better avoid to do such test as a precaution,to avoid any damage.
Still if u want to check ,do it at low volumes.
I wont be doing more anymore such tests and test were at 70% volume or less, so that drivers are not damaged.

I dont have any equipment to measure the spl or anything like rew or umik1.
 

Lizard King

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Interesting observation.
I have also noticed something similar, albiet in a far less scientific way.
While testing the SPL of my system with a mobile app, I can see my Wharfedale Diamond 230 floorstanders go down to 31 Hz, sometimes even 25 Hz. Even though the dB is quite low at those frequency bands, it's far below it's rated frequency range.
Does it mean that some manufacturers are conservative with their published measurements?
 

spirovious

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Yes correct, but I think we can't hear 10hz. All we can feel the air moving by drivers.
That's the point. Some speakers claims more than 20k. Even some amps, but what's use when we can't hear it. Manufacturere just want to convey how superior response their products have.In real world ,no use.
 

Nitin K

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Interesting observation.
I have also noticed something similar, albiet in a far less scientific way.
While testing the SPL of my system with a mobile app, I can see my Wharfedale Diamond 230 floorstanders go down to 31 Hz, sometimes even 25 Hz. Even though the dB is quite low at those frequency bands, it's far below it's rated frequency range.
Does it mean that some manufacturers are conservative with their published measurements?
Their speakers may go low. But what is important is, how much low do they go and at what loudness measurements. Are those frequencies heard loudly or felt. How much is their impact in the room in all practicality.
Earlier, I have had a subwoofer which claimed to go down to 18 hz. But in all practicality the bass of this sub was impactful till 35 hz as per people who had measured it. Below that it sounded feeble where the sfx was strong.
Replaced the earlier one with an impactful sub with true measurements and no complaints so far.
 
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Lizard King

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Their speakers may go low. But what is important is, how much low do they go and at what loudness measurements. Are those frequencies heard loudly or felt. How much is their impact in the room in all practicality.
Earlier, I have had a subwoofer which claimed to go down to 18 hz. But in all practicality the bass of this sub was impactful till 35 hz as per people who had measured it. Below that it sounded feeble where the sfx was strong.
Replaced the earlier one with an impactful sub with true measurements and no complaints so far.
I agree and understand.
Beyond being a fleck on the histogram it serves no purpose. In fact that bass on that speaker, while low enough, is bloated, slow and undefined. As if not coming from any known instrument but due to some jugglery of the cabinet and bass ports.
 

Nitin K

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I agree and understand.
Beyond being a fleck on the histogram it serves no purpose. In fact that bass on that speaker, while low enough, is bloated, slow and undefined. As if not coming from any known instrument but due to some jugglery of the cabinet and bass ports.
Very true and how accurate is the production of the speaker at those frequencies is also an important factor which I missed mentioning.
 
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