Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Software Tools SPICE, PCB CAD, speaker design and measurement software, calculators

VituixCAD
VituixCAD
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 12th November 2019, 02:50 PM   #1581
shining31 is online now shining31
diyAudio Member
 
Join Date: Mar 2018
Hi guys !
I've a question about "listening distance" option.

Does,for exemple, the soft considers that measurements are taken at 1m distance ?

I mean, for simulate a listening distance, don't we need to know the measurement distance ?

Or maybe, this "listenning distance" is added to measurement distance ?

My idea is that to simulate the distance '3 meters' I need to know the measurement distance 'X'. If not, is that magic ?

By the way, your tool and papers are amazingly usefull for the hobbyist !!
  Reply With Quote
Old 12th November 2019, 04:31 PM   #1582
kimmosto is offline kimmosto  Finland
diyAudio Member
 
kimmosto's Avatar
 
Join Date: Oct 2005
Location: Kuopio
* Measurement distance can be shorter than simulated listening distance set in Options window. >2000 mm is usually impossible due to reflections so we have to live with 600...1200 mm measurement distances.
* You don't have to make any SPL or delay scaling to measurement data if you measure all drivers with the same voltage and at the same distance from mic to driver's origin i.e. rotation center while off-axis measurement sequence.
* Far field measurement distance should be actual "far field" i.e. construction with huge cone or horn might require more than 1000 mm. SPL should drop 6 dB when distance doubles from measurement point. Otherwise error in magnitude scaling from measurement distance to simulated mic distance will be more obvious.

All diffraction/baffle loss, leaking radiator and back wave effects are not included if measurement distance is short. But reflections are usually much bigger bad so shortish measurement distance is natural selection if anechoic is not available.
  Reply With Quote
Old 12th November 2019, 04:56 PM   #1583
shining31 is online now shining31
diyAudio Member
 
Join Date: Mar 2018
Thks kimmosto
Thanks you for your answer.
these points are well described into you papers and literrature.

My question was more theorical and like:

I feed your simulation with measurements taken at "X" distance (Let say 80cm, merged, quasi anechoid, etc etc, woofer then tweeter ...)
And then I ask to the simulation a listenning distance of 3 meters without specifying that measurements was taken at "X" distance.

So how mathematical you pass from "X" (unknown) to 3 meters ?

Last edited by shining31; 12th November 2019 at 05:02 PM.
  Reply With Quote
Old 13th November 2019, 04:58 AM   #1584
kimmosto is offline kimmosto  Finland
diyAudio Member
 
kimmosto's Avatar
 
Join Date: Oct 2005
Location: Kuopio
Quote:
Originally Posted by shining31 View Post
So how mathematical you pass from "X" (unknown) to 3 meters ?
Crossover simulator does not have data to make anything to shape of measured responses. Just location of each driver (compared to speaker's origin), position of virtual mic at each simulated 3D point and measurement data of drivers in two planes are available. As mentioned, large drivers and horns could use measuring distance longer than 1 m. Designer is free to measure at 2.5 m if large anechoic is available. That makes near field measurements, diffraction simulations and merging unnecessary.

Program is able to do:
* Magnitude scaling by distance: nominal listening distance (set in Options window) divided by direct 3D distance from driver's origin (rotation center) to location of virtual mic in the simulation. This is standard -6 dB to double distance. The rest is included included in measurement data.
* Delay offset by distance: phase difference at c=344.0 m/s due to distance difference between nominal listening distance (set in Options window) and direct 3D distance from driver's origin (rotation center) to location of virtual mic in the simulation. The rest is included (in dual channel) measurement data.
* Frequency response interpolation to direction of virtual mic in the simulation. This is weighted average of four measured responses; two responses to nearest angles in horizontal plane and two responses in vertical plane. Responses could be mirrored hor-hor, ver-ver or hor-ver if not measured, assuming adequate symmetry of construction.
  Reply With Quote
Old 13th November 2019, 06:40 AM   #1585
shining31 is online now shining31
diyAudio Member
 
Join Date: Mar 2018
Oh, thanks you very much! It's more clear to me now
  Reply With Quote
Old 13th November 2019, 08:08 AM   #1586
kimmosto is offline kimmosto  Finland
diyAudio Member
 
kimmosto's Avatar
 
Join Date: Oct 2005
Location: Kuopio
Quote:
Originally Posted by kimmosto View Post
The rest is included (in dual channel) measurement data.
This statement assumes that driver measurements are captured according instructions.
Mentioned already half a million times but group using USB mics or other single channel gear/mode without timing reference is out of the game before start. Worst case scenario is previous gear/mode added with minimum phase extraction which ruins also polarity information in measurement data in addition to timing difference between acoustic center and rotation center including timing differences of drivers.
  Reply With Quote
Old 13th November 2019, 08:11 AM   #1587
AllenB is offline AllenB  Australia
diyAudio Moderator
 
AllenB's Avatar
 
Join Date: Oct 2008
VituixCAD
Holmimpulse does single channel time referenced measurements.
  Reply With Quote
Old 13th November 2019, 08:38 AM   #1588
kimmosto is offline kimmosto  Finland
diyAudio Member
 
kimmosto's Avatar
 
Join Date: Oct 2005
Location: Kuopio
Measuring application does not need two actual input channels though it's common approach. Maybe to avoid some compatibility and driver issues. Only requirement is that application "knows" timing difference of output and input. CLIO measures with single channel too.
  Reply With Quote
Old 13th November 2019, 06:50 PM   #1589
Pallas is offline Pallas  Pakistan
diyAudio Member
 
Join Date: Aug 2004
Default VituixCAD

Quote:
Originally Posted by kimmosto View Post
This is now done in rev. 2.0.29.0. Reference selection via context menu of Power & DI chart.



Typical result equals to 10-15 deg off-axis as DI reference so this feature is not very special. Enables scrolling of Reference angle without change in DI curve, and hiding diffraction problem in publication while showing 0 deg as axial response


Awesome, thanks! I agree the differences arenít huge when you know the LW and can match it closely to a reference angle, but this matches the current agreed US industry standard (CTA2034A).

I apologize if this is asked and answered already, but does VCAD use the same (or basically the same) angular coefficients as CTA2034A (at last at those 10deg increments) to calculate power response?
__________________
Serious Audio Blog
  Reply With Quote
Old 13th November 2019, 07:27 PM   #1590
kimmosto is offline kimmosto  Finland
diyAudio Member
 
kimmosto's Avatar
 
Join Date: Oct 2005
Location: Kuopio
Quote:
Originally Posted by Pallas View Post
...does VCAD use the same (or basically the same) angular coefficients as CTA2034A (at last at those 10deg increments) to calculate power response?
You have at at least eight different coefficient series with the same 10 deg angle step depending on what sector and planes are measured or included in power calculation. I have not much interest to buy any standard with that big money, but here are all eight captured from VituixCAD in debug mode if you like to compare

Hor plane, half space, single side: 0...+90 deg
Plane Angle Weight
hor 0 0.00350023622065133
hor 10 0.02784225903657210
hor 20 0.05483854512118090
hor 30 0.08016858976192520
hor 40 0.10306275237001700
hor 50 0.12282540539961600
hor 60 0.13885607063880100
hor 70 0.15066766443618800
hor 80 0.15790129749119800
hor 90 0.16033717952385100

Hor plane, half space: -90...+90 deg
Plane Angle Weight
hor -90 0.080309140242688700
hor -80 0.079089063948744500
hor -70 0.075465906467715200
hor -60 0.069549755606255600
hor -50 0.061520370614574300
hor -40 0.051621720292578900
hor -30 0.040154570121344300
hor -20 0.027467343656165600
hor -10 0.013945535853140800
hor 0 0.001753186393583850
hor 10 0.013945535853140800
hor 20 0.027467343656165600
hor 30 0.040154570121344300
hor 40 0.051621720292578900
hor 50 0.061520370614574300
hor 60 0.069549755606255600
hor 70 0.075465906467715200
hor 80 0.079089063948744500
hor 90 0.080309140242688700

Hor plane, full space, single side: 0...+180 deg
Plane Angle Weight
hor 0 0.00190265095412723
hor 10 0.01513443590133860
hor 20 0.02980901962620920
hor 30 0.04357787137382910
hor 40 0.05602263155122210
hor 50 0.06676517241775070
hor 60 0.07547908730517340
hor 70 0.08189960831908940
hor 80 0.08583165117743130
hor 90 0.08715574274765820
hor 100 0.08583165117743130
hor 110 0.08189960831908920
hor 120 0.07547908730517320
hor 130 0.06676517241775080
hor 140 0.05602263155122210
hor 150 0.04357787137382920
hor 160 0.02980901962620910
hor 170 0.01513443590133870
hor 180 0.00190265095412723

Hor plane, full space: -180...+180 deg
Plane Angle Weight
hor -180 0.0
hor -170 0.007581643171283030
hor -160 0.014932921951303100
hor -150 0.021830471454256100
hor -140 0.028064713128822900
hor -130 0.033446222696400700
hor -120 0.037811485711953400
hor -110 0.041027865867683600
hor -100 0.042997635080126100
hor -90 0.043660942908512100
hor -80 0.042997635080126100
hor -70 0.041027865867683600
hor -60 0.037811485711953500
hor -50 0.033446222696400600
hor -40 0.028064713128822900
hor -30 0.021830471454256000
hor -20 0.014932921951303100
hor -10 0.007581643171283000
hor 0 0.000953138967830172
hor 10 0.007581643171283000
hor 20 0.014932921951303100
hor 30 0.021830471454256000
hor 40 0.028064713128822900
hor 50 0.033446222696400600
hor 60 0.037811485711953500
hor 70 0.041027865867683600
hor 80 0.042997635080126100
hor 90 0.043660942908512100
hor 100 0.042997635080126100
hor 110 0.041027865867683600
hor 120 0.037811485711953400
hor 130 0.033446222696400700
hor 140 0.028064713128822900
hor 150 0.021830471454256100
hor 160 0.014932921951303100
hor 170 0.007581643171283030
hor 180 0.000953138967830172

Both planes, half space, single side: 0...+90 deg
Plane Angle Weight
hor 0 0.00175011811032567
hor 10 0.01392112951828600
hor 20 0.02741927256059040
hor 30 0.04008429488096260
hor 40 0.05153137618500870
hor 50 0.06141270269980780
hor 60 0.06942803531940040
hor 70 0.07533383221809390
hor 80 0.07895064874559910
hor 90 0.08016858976192530
ver 0 0.00175011811032567
ver 10 0.01392112951828600
ver 20 0.02741927256059040
ver 30 0.04008429488096260
ver 40 0.05153137618500870
ver 50 0.06141270269980780
ver 60 0.06942803531940040
ver 70 0.07533383221809390
ver 80 0.07895064874559910
ver 90 0.08016858976192530

Both planes, half space: -90...+90 deg
Plane Angle Weight
hor -90 0.040154570121344400
hor -80 0.039544531974372300
hor -70 0.037732953233857600
hor -60 0.034774877803127800
hor -50 0.030760185307287200
hor -40 0.025810860146289500
hor -30 0.020077285060672200
hor -20 0.013733671828082800
hor -10 0.006972767926570410
hor 0 0.000876593196791927
hor 10 0.006972767926570410
hor 20 0.013733671828082800
hor 30 0.020077285060672200
hor 40 0.025810860146289500
hor 50 0.030760185307287200
hor 60 0.034774877803127800
hor 70 0.037732953233857600
hor 80 0.039544531974372300
hor 90 0.040154570121344400
ver -90 0.040154570121344400
ver -80 0.039544531974372300
ver -70 0.037732953233857600
ver -60 0.034774877803127800
ver -50 0.030760185307287200
ver -40 0.025810860146289500
ver -30 0.020077285060672200
ver -20 0.013733671828082800
ver -10 0.006972767926570410
ver 0 0.000876593196791927
ver 10 0.006972767926570410
ver 20 0.013733671828082800
ver 30 0.020077285060672200
ver 40 0.025810860146289500
ver 50 0.030760185307287200
ver 60 0.034774877803127800
ver 70 0.037732953233857600
ver 80 0.039544531974372300
ver 90 0.040154570121344400

Both planes, full space, single side: 0...+180 deg
Plane Angle Weight
hor 0 0.000951325477063614
hor 10 0.007567217950669310
hor 20 0.014904509813104600
hor 30 0.021788935686914500
hor 40 0.028011315775611100
hor 50 0.033382586208875400
hor 60 0.037739543652586700
hor 70 0.040949804159544700
hor 80 0.042915825588715700
hor 90 0.043577871373829100
hor 100 0.042915825588715700
hor 110 0.040949804159544600
hor 120 0.037739543652586600
hor 130 0.033382586208875400
hor 140 0.028011315775611000
hor 150 0.021788935686914600
hor 160 0.014904509813104600
hor 170 0.007567217950669340
hor 180 0.000951325477063614
ver 0 0.000951325477063614
ver 10 0.007567217950669310
ver 20 0.014904509813104600
ver 30 0.021788935686914500
ver 40 0.028011315775611100
ver 50 0.033382586208875400
ver 60 0.037739543652586700
ver 70 0.040949804159544700
ver 80 0.042915825588715700
ver 90 0.043577871373829100
ver 100 0.042915825588715700
ver 110 0.040949804159544600
ver 120 0.037739543652586600
ver 130 0.033382586208875400
ver 140 0.028011315775611000
ver 150 0.021788935686914600
ver 160 0.014904509813104600
ver 170 0.007567217950669340
ver 180 0.000951325477063614

Both planes, full space: -180...+180 deg
Plane Angle Weight
hor -180 0.0
hor -170 0.003790821585641510
hor -160 0.007466460975651560
hor -150 0.010915235727128000
hor -140 0.014032356564411400
hor -130 0.016723111348200300
hor -120 0.018905742855976700
hor -110 0.020513932933841800
hor -100 0.021498817540063000
hor -90 0.021830471454256000
hor -80 0.021498817540063000
hor -70 0.020513932933841800
hor -60 0.018905742855976700
hor -50 0.016723111348200300
hor -40 0.014032356564411500
hor -30 0.010915235727128000
hor -20 0.007466460975651570
hor -10 0.003790821585641500
hor 0 0.000476569483915086
hor 10 0.003790821585641500
hor 20 0.007466460975651570
hor 30 0.010915235727128000
hor 40 0.014032356564411500
hor 50 0.016723111348200300
hor 60 0.018905742855976700
hor 70 0.020513932933841800
hor 80 0.021498817540063000
hor 90 0.021830471454256000
hor 100 0.021498817540063000
hor 110 0.020513932933841800
hor 120 0.018905742855976700
hor 130 0.016723111348200300
hor 140 0.014032356564411400
hor 150 0.010915235727128000
hor 160 0.007466460975651560
hor 170 0.003790821585641510
hor 180 0.000476569483915086
ver -180 0.0
ver -170 0.003790821585641510
ver -160 0.007466460975651560
ver -150 0.010915235727128000
ver -140 0.014032356564411400
ver -130 0.016723111348200300
ver -120 0.018905742855976700
ver -110 0.020513932933841800
ver -100 0.021498817540063000
ver -90 0.021830471454256000
ver -80 0.021498817540063000
ver -70 0.020513932933841800
ver -60 0.018905742855976700
ver -50 0.016723111348200300
ver -40 0.014032356564411500
ver -30 0.010915235727128000
ver -20 0.007466460975651570
ver -10 0.003790821585641500
ver 0 0.000476569483915086
ver 10 0.003790821585641500
ver 20 0.007466460975651570
ver 30 0.010915235727128000
ver 40 0.014032356564411500
ver 50 0.016723111348200300
ver 60 0.018905742855976700
ver 70 0.020513932933841800
ver 80 0.021498817540063000
ver 90 0.021830471454256000
ver 100 0.021498817540063000
ver 110 0.020513932933841800
ver 120 0.018905742855976700
ver 130 0.016723111348200300
ver 140 0.014032356564411400
ver 150 0.010915235727128000
ver 160 0.007466460975651560
ver 170 0.003790821585641510
ver 180 0.000476569483915086
  Reply With Quote

Reply


VituixCADHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


New To Site? Need Help?

All times are GMT. The time now is 08:25 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright ©1999-2020 diyAudio
Wiki