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I think I need a program loop to get the graph to show up correctly. Suggestions? Quick Sound Loss.smz (133kb) downloaded 47 time(s).Edited by user 13 April 2018 08:19:33(UTC)
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Originally Posted by: ElSid I think I need a program loop to get the graph to show up correctly.Suggestions? "Why does log10 look different ?" because you have two different formulas, thus two different results
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Jean, The second equation is off/not evaluated. Graphically log to base x and log10 display differently. Question is about graph though
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Strict math seems correct to me; let's compare the values for different directivity factors at ssame distance. we have: to simplify things we can get rid of the absolute value; in your example all numbers are above 1, plus logarithms' arguments are <= 8 in numerator and >= 12 in denominator (4*pi*distance_greater_than_1), thus: Code:|10*log10(a/b)| = 10*(log10(b)-log10(a)) = 10*(log10(f(x))-log10(Q)) = 10*log10(f(x))-10*log10(Q)
at same distance, log10(f(x)) is the same for every directivity factor Q Code:10*log10(f(x))-10*log10(Q) = const-10*log10(Q)
10*log10(2)=3, 10*log10(4)=6, 10*log10(8)=9 (approx)
Lp(Q,x)=Lw(Q,1.5)-|10*log10(a/b)|=Lw(Q,1.5)-const+10*log10(Q)
Lw(Q,1.5) loses -3dB when you double Q, but at the same time the absolute value term adds +3B -> so why values are so close (and functions overlapped in the plot) In fact, if you go further, you can do the same for Lw: Code:Lw(Q,dist) = Ltot+|10*log10(Q/f(dist))| = Ltot+10*log10(f(dist))-10*log10(Q) = const2-10*log10(Q)
Lp(Q,x) = Lw(Q,1.5)-const1+10*log10(Q) = const2-10*log10(Q)-const1+10*log10(Q) = const2-const1 = constant
and decimal shown in the workshet are only because different decimal places shown in the results Edited by user 10 April 2018 22:17:02(UTC)
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Rank: Advanced Member Groups: Registered, Advanced Member Joined: 13/01/2012(UTC) Posts: 2,652 Location: Italy Was thanked: 1339 time(s) in 878 post(s)
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What might be wrong... You have sound pressure measured by the vendor -> You have to calculate the power level for the distance and directivity condition of the vendorThen you have the sound power level of your source... it's a constant! Use this value to estimate the sound power at various distances for various directivity conditions! Quick Sound Loss - rev.1.sm (135kb) downloaded 41 time(s).Edited by user 10 April 2018 20:53:37(UTC)
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Davide, I did the same thing, where I assumed directivity is b=2 on Lw. I'll just document that and move on as the rest of the math appears to work out
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Originally Posted by: ElSid Jean, The second equation is off/not evaluated.Graphically log to base x and log10 display differently.Question is about graph though Few more things you can do as real project. Line style "splines" is a bit smoother in the low region. Quick Sound Loss - rev.2.sm (135kb) downloaded 35 time(s).
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Funny ... OK, here I am as I had done most of the items that Davide and Jean added. Now I would like to add a "dot" or a vertical line where the dB.final is. Please use this sheet Quick Sound Loss.smz (136kb) downloaded 34 time(s).Jean, I did not see where you used a spline All should I be using "cinterp" to place the "dot? Edited by user 10 April 2018 23:45:56(UTC)
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Originally Posted by: ElSid Jean, I did not see where you used a spline
All should I be using "cinterp" to place the "dot? 1. spline is for line style ... line/spline. 2. what that gyzma #,#,#,,,does in maths ? 3. X_Y plot does not support " in your plot suggestion 4. X_Y is for final/final/final ... project once done, if you rework something above=> it will freak the plot X_Y plot has slightly pregnant memory. Doctored in red . Quick Sound Loss (3).sm (141kb) downloaded 42 time(s).
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Originally Posted by: CBG Something like this? Carlos, I think you attached the wrong file. Yes, that is what I was looking for. Jean, When I double click the graph on your latest file, my computer locks up. I'm on version 0.99.6671. NOW my file is locking up!!! ARRG Edited by user 11 April 2018 03:26:26(UTC)
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Originally Posted by: ElSid Jean, When I double click the graph on your latest file, my computer locks up.I'm on version 0.99.6671. My 6179 opens your 6671 ... your 6671 freezes opening 6179 Is it a bug ? BTW, attach an image of the polynomials that fail [as you reported].
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Originally Posted by: Jean Giraud Few more things you can do as real project. Thanks Elsid, Nice project, saved for myself, you can have it as is. Jean Inst_dB Sound.sm (143kb) downloaded 33 time(s).
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Well, Here we go again ... I found a quirk. Depending on values dB initial values, neither solve nor FindRoot is functional. I was plugging in values by hand without seeing an issue. I tried a "higher" dB set of values (86 vs 75) for equipment and the calculation *zap* Quick Sound Loss.smz (169kb) downloaded 32 time(s).Also, the X-Y plot legend information *ZAP* Edited by user 13 April 2018 09:45:39(UTC)
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Originally Posted by: ElSid Well, Here we go again ... I found a quirk.Depending on values dB initial values, neither solve nor FindRoot is functional.I was plugging in values by hand without seeing an issue.I tried a "higher" dB set of values (86 vs 75) for equipment and the calculation *zap* That one was Doctored and you don't use the Doctored version. Explained before, if above X_Y something is Doctored, zap. Quick Sound Loss (4) Doctored 20180413.sm (168kb) downloaded 38 time(s).
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Found the issue(s). See revamped file. Still having issues in that X-Y plot Labels for the legend *zap* Quick Sound Loss.smz (143kb) downloaded 61 time(s).Edit: Two bugs - X-Y Plot. If functions crash, *Zap* to the legend titles. All other titles OK. Legend is empty due to laziness after last 5 crashes
- solve(4) did not like trying to cancel units in the denominator of the final function (#dist). As I was adding units to x:0-100 FT and dividing the units meters in the function, the function crashed in the solve block (Just the function, with all values plugged in except for x = vector, so it's a solve(4) issue).
This is one of those sheets where UNITS are huge! The equations are all based off of SI/metric references. Major issue There is additional documentation and function definition updates. Sanity check the graph x scale (adjusted for feet since I'm in the US). Should be good now Edited by user 13 April 2018 20:37:55(UTC)
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Originally Posted by: ElSid Found the issue.I'll post revamp file.Still having issues in that X-Y plot Labels for the legend *zap* Clik on "list", edit "series name".
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Revisiting this old calc with SMath newer features and some function definitions. - No longer works if I redefine the logarithmic sum with vectorize
- I cannot get the "heat capacity function" to work for ploting
Sound Loss (Quick).sm (477kb) downloaded 15 time(s).Thanks for the help. Edited by user 26 January 2021 02:55:57(UTC)
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Hi. Some notes, but I'm not sure if this solve all of the issues: 1. Use count inside rangeindividual, but not outside. You use it in f(x, b ), and guess that could be problematic. 2. After that, you divide x by 'm in f and x by feet in rangeindividual, choose only one. 3. Maybe here don't affect, but if rangeindividual have not f(#,#) as parameter, define f before rangeindividual, you know, just in case. Best regards. Alvaro.
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