 Posted: Mon Nov 17, 2008 3:07 pm |
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| Jörn |
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| Joined: 28 Jun 2007 |
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| Is there a possibility to get octave-band-data out of the mapping? The "Send Value To"-function always delivers third-ocatve-data, doesn't it?
Thx. |
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| Posted: Mon Nov 17, 2008 9:38 pm |
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| Bruce |
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| Joined: 19 Apr 2005 |
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| Location: Minneapolis, MN, USA |
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| Yes it does. If you send it to Excel, here is the equation to convert 3 one-third octave values to an octave value: | Code: | | =10*LOG(10^(<Value1>/10)+10^(<Value2>/10)+10^(<Value3>/10)) |
If you add a column to the Excel sheet, then enter this in the octave band row. Next point each <ValueX> to the 3 one-third octave cells. This will give you the octave value. |
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Best Regards,
Bruce C. Olson |
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| Posted: Tue Nov 18, 2008 5:24 pm |
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| Jörn |
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| Thanks for the reply, Bruce.
I was just wondering, if there's a way to avoid these additional calculations... but it seems, there's none.
However, don't the three third-octave bands have to be weighted differently with respect to the absolute bandwidth?
Regards,
Jörn |
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| Posted: Wed Nov 19, 2008 7:23 am |
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| Bruce |
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| Location: Minneapolis, MN, USA |
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| | Jörn wrote: | | However, don't the three third-octave bands have to be weighted differently with respect to the absolute bandwidth? |
Jörn,
I'm not sure what you mean by "absolute bandwidth". So I don't know why there would need to be any weighting of the one-third bands. |
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Last edited by Bruce on Fri Nov 28, 2008 5:52 pm; edited 1 time in total
_________________
Best Regards,
Bruce C. Olson |
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| Posted: Thu Nov 27, 2008 5:42 pm |
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| Jörn |
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| Hi Bruce,
with "absolute bandwidth" I mean the fact, that the three one-third-octave are not equally broad. So they should not be averaged linearly but weighted by something like:
<Value1>*0,25+<Value2>*0,35+<Value3>*0,4 |
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| Posted: Fri Nov 28, 2008 11:23 am |
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| PaulMalpas |
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| Location: Cambridge, UK |
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| Hi Jorn
I think what you refer to is rooted in the confusions between energy and energy density. In engineering, the levels seen per band are total in-band energy, as would be seen on an RTA, giving a flat response for pink noise. In EASE, levels are currently shown as energy density, and so to get total energy you multiply by the bandwidth. Higher bands (octave or third) have larger bandwidths, so perhaps you are right to 'weight' these in your sum proprtionally to the relative bandwidth.
At least I think i have that the right way round, though I often confuse myself over it!
Paul |
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| Posted: Mon Dec 01, 2008 4:18 pm |
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| Jörn |
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| Paul,
thank you for your reply. Sight is getting clearer...
To put it short:
For energy-density levels my calculation would be right, for energy levels Bruce's would be.
Bruce, could you please confirm, that EASE delivers energy-density levels, as Paul is not 100% sure.
Regards
Jörn |
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| Posted: Fri Dec 19, 2008 9:57 am |
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| ChrisH |
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| Guys
You can get octave values out of the mapping results, if you just preselect 'One Octave' before hitting Send Values To it will export the octave band calc - no need for any further work?! (at least true for version 4.2.3.36). Alternatively the ASCII export function has options for 1/3 / 1 octave / 3 octave output.
Whilst Bruce's formula for adding 1/3 octave bands is of course correct, I'm not sure it is suitable for EASE data output? Most 1/3 octave band data for speakers in EASE seems to be extrapolated from the octave band sensitivity, i.e. they are not true 1/3 octave band levels. Adding the 1/3 octave values will give you a much higher result (i.e. ~ +4.8dB if each band is equal) than the result EASE gives for the octave band.
Maybe Stefan can shed some light on how the 1/3 oct bands are derived / used in EASE? |
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