THD+N graphs.

[STRONGBADF1]

How do you read a THD+N graph like the one on this page

http://www.soundstagemagazine.com/measurements/energy_rc_10/.

What's good and what's bad?(audible)

SBF1

 

[agarwalro]

Good question. I would like to learn that too.

 

[silversurfer]

Have you read this?

http://www.soundstagemagazine.com/measurements/test_loudspeakers.htm

 

[STRONGBADF1]

Have you read this?

http://www.soundstagemagazine.com/measurements/test_loudspeakers.htm

Hi silversurfer,

Thanks for responding!

Yes. It does not answer my question though. What is concidered good?

I understand that 90-95db is louder than one normally listen at but we all have a song or two that we like to listen to at abnormally loud volumes. This measurement would then come into play then right?

SBF1

 

[STRONGBADF1]

bump.......

 

[silversurfer]

I think we know lower is better.

Maybe Gene or Clint can chime in.

 

[mtrycrafts]

Hi silversurfer,
Thanks for responding!
Yes. It does not answer my question though. What is concidered good?
I understand that 90-95db is louder than one normally listen at but we all have a song or two that we like to listen to at abnormally loud volumes. This measurement would then come into play then right? SBF1

This is the distortion in % for the differences in dB between the two curves on the THD+N curve and the spl curve response.

Equal (or 0dB difference) = 100 %
-10dB = 31.6%
-20dB = 10.0%
-30dB = 3.16%
-40dB = 1.0%
-50dB = <0.5%


So, check the difference between the peak at about the 800Hz point and find the difference dB, then check what is the %.

At the low end, probably 100Hz and maybe even 200Hz and lower, it is very difficult to hear distortions and need almost 100% before some would hear it.
A different point at higher frequencies but I would not worry about 1% with music content

http://www.mastersonaudio.com/features/20040401.htm

http://www.axiomaudio.com/distortion.html#

No, I didn't do the difference calc for those graphs before posting

ps.
now I have. I might be concerned in that band at 400Hz-1kHz at higher levels. After all, 95 dB spl is below reference levels and at 6.5ft. Imagine peaks to 105dB

 

[silversurfer]

Remember though, that is 95dB with ONE speaker, not two, three, or five.

When talking about reference level, you are talking about all channels combined(with or without sub?) correct?

 

[mtrycrafts]

Remember though, that is 95dB with ONE speaker, not two, three, or five.

When talking about reference level, you are talking about all channels combined(with or without sub?) correct?

Not necessarily. Any one channel can reach reference levels when the master volume is at the proper setting, the setting position when calibrated.
The peaks will reach that level, if that is on the CD/DVD source and at 1 meter, even louder. Hence, that speaker will distort something awful in that band. From that graph, the THD+N is increasing with volume, as most speakers will as well.

If that speaker will not be played at that level, then it may not be an issue.
But, those speakers are a good example what happens with THD+N as volume increases. And, some worry about wires, CD players, receivers, etc.

 

[STRONGBADF1]

Thank you.

I need to read before I can respond...

SBF1

P.S. Maybe tomorrow...Jack and coke...disturbing the thought process...