Measuring Frequency Response of Nearfield Monitors.

solo2racr

solo2racr

SUCK, SQUEEZE, BANG, BLOW
Just out of passing curiosity, I was wondering if anyone has done this? Spec sheets are all fine and such but, what kind of response do you get once they are in place and you're listening to them? I bet one would be surprised at the frequency response one gets at their listening position.
 
I assume you guys have measured. Besides the obvious "treat the room" answer, (not always practical to do it right), would an EQ in front of the monitors help? I would think it would, to a degree. Depending on the root problem.
 
solo2racr said:
I assume you guys have measured. Besides the obvious "treat the room" answer, (not always practical to do it right), would an EQ in front of the monitors help? I would think it would, to a degree. Depending on the root problem.
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If the root problem is the speakers themselves then maybe some careful and informed application of filters could help. Attempting to eq the room response will most likely lead to trouble.
 
bouldersoundguy said:
If the root problem is the speakers themselves then maybe some careful and informed application of filters could help. Attempting to eq the room response will most likely lead to trouble.
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That's what I was alluding to when I said "Depending on the root problem". There are certain things no amount of EQ will fix. But then, this gets into why nearfield and relative low volume (85-90db) is better in a poor room.
 
solo2racr said:
But then, this gets into why nearfield and relative low volume (85-90db) is better in a poor room.
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Nearfields may help you deal with a poor room, but volume doesn't matter much. Room reflections will always be in the same proportion to the direct sound regardless of volume.
 
My thinking behind what I said, and it may be wrong, is that sound energy will decay at lower volumes before it has much chance to reflect off some surface. With the converse true as well. Louder volumes will have enough energy to reflect back and be heard more easily. So, in a poor room, reflection are minimized at lower volumes. This all assumes that decay is progressive and not linear, which I have no idea but, seems like I read that somewhere at sometime.
 
solo2racr said:
My thinking behind what I said, and it may be wrong, is that sound energy will decay at lower volumes before it has much chance to reflect off some surface. With the converse true as well. Louder volumes will have enough energy to reflect back and be heard more easily. So, in a poor room, reflection are minimized at lower volumes. This all assumes that decay is progressive and not linear, which I have no idea but, seems like I read that somewhere at sometime.
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Sound follows the inverse square law for distance vs. power. A particular reflection path will always be -xdB relative to the direct path regardless of the monitoring volume.

Changing the listening position's distance from the monitors will change the balance of direct and reflected paths, but simple volume changes will not.
 
bouldersoundguy said:
Sound follows the inverse square law for distance vs. power. A particular reflection path will always be -xdB relative to the direct path regardless of the monitoring volume.

Changing the listening position's distance from the monitors will change the balance of direct and reflected paths, but simple volume changes will not.
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So....Decay is linear.
 
I think I get it. A sine wave would be linear decay but, we don't listen to sine waves. Which means it's also frequency dependent, which is logarithmic. That also explains why you can hear lower frequencies, at a given SPL, at a further distance because there is more energy behind the wave form.
 
solo2racr said:
Btyre2013........How did you measure them? What software? What conditions?
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Umm.. don't trip on that, looks surprisingly like these..
https://www.google.com/search?q=kh+...oring_studio-monitors_subwoofer_KH810;250;187
..i.e likely not a room plot.

I'll add that I've never tried to do 'proper speaker measuring, just done a few here at home with REW figuring it's just giving a general picture (18" out form the monitor for example) - 'flatter than 'in the room', but it definitely still has a least some of the room- and likely the nearby boundary effects in there as well.
From what I've read plotting (just) the speaker is not so easy.
 
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I wasn't. Unless the answer was "on an infinite baffle in an anechoic chamber". The best I can get, without the sub, on my own design monitors, is +/-3db from 120hz to about 15Khz. The sub covers the rest of the bottom and the top is what it is. I'm working on another pair that I hope will have less deviation.

Edit.....my own design monitors mentioned above were measured in place and the measurement was taken at the listening position.
 
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solo2racr said:
I think I get it. A sine wave would be linear decay but, we don't listen to sine waves. Which means it's also frequency dependent, which is logarithmic. That also explains why you can hear lower frequencies, at a given SPL, at a further distance because there is more energy behind the wave form.
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Still not quite right, and I don't think I can explain it any more clearly.
 
solo2racr said:
I'll research it some more and see if I can get my head wrapped around it. First is to un-learn what I thought I knew as correct.
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Part of the problem is you're mixing up frequency and amplitude (volume). While there are some frequency dependent effects on sound in air, for the most part power falls according to the inverse square law. To the best of my knowledge that same law applies to all three-dimensional fields whether gravitational, electromagnetic or acoustic.
 
Here's another way to look at it. Say you're monitoring at 83dB SPL and there's a reflection off a wall that's 70dB SPL, the difference being 13dB. If you turn the monitor level down 10dB the direct SPL will be 73dB and the reflected will be 60dB so the difference will still be 13dB. Since hearing and the dB scale are both logarithmic that 13dB difference sounds about the same regardless of the actual monitoring volume.
 
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