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

Multi-Way Conventional loudspeakers with crossovers

frequency amplitude R//C serie correction
frequency amplitude R//C serie correction
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 24th February 2020, 06:48 PM   #1
diyiggy is offline diyiggy
diyAudio Member
 
diyiggy's Avatar
 
Join Date: Jan 2019
Default frequency amplitude R//C serie correction

Hi,

I'm looking for hat is correcting 1R//10 uF in serie on the tweeter signal please ?

The tweeter is a 4 ohms nominal impedance (3.5 measured at voice coil) and XO is a LR4 at 2700 hz. this RC is between the two coils.

I looked for on line calculators but found at best RCL notch spreadsheet.

I assume this RC in serie with the signal gives a bump a the bottom or middle frequency of the tweeter to match the mid driver at corret spl but I can't find the frequencies windows involved by these RC values.

Are you please aware of a link about such frequency network correction please ? Bagbys's excells ?
  Reply With Quote
Old 24th February 2020, 08:47 PM   #2
diyiggy is offline diyiggy
diyAudio Member
 
diyiggy's Avatar
 
Join Date: Jan 2019
Hum, I have tried Xsim free soft, starting from a LR4 with the amp tuned at 4 ohms... (not sure Z of driver can be setuped in Xsim ?) :

the climbing curve is starting slowly from 20 K Hz dB to end at 5.5 k Hz at +3 dB (flat between 4.9 k & 6.7 k) then falls from 4.9 k to 3.6 k Hz 0 dB.

assuming esr of lytics are flat at all frequencies ?!




Edit : seems to be the result of the filter cause the R//C is not working, same result with and without... so back to the beginning

Last edited by diyiggy; 24th February 2020 at 09:06 PM.
  Reply With Quote
Old 24th February 2020, 10:12 PM   #3
AllenB is offline AllenB  Australia
diyAudio Moderator
 
AllenB's Avatar
 
Join Date: Oct 2008
frequency amplitude R//C serie correction
Quote:
Originally Posted by diyiggy View Post
(not sure Z of driver can be setuped in Xsim ?)
Yes, it can.
Quote:
assuming esr of lytics are flat at all frequencies
Mostly in the audio band, yes.
Attached Images
File Type: png Screenshot from 2020-02-25 10-09-10.png (16.6 KB, 89 views)
  Reply With Quote
Old 24th February 2020, 11:24 PM   #4
diyiggy is offline diyiggy
diyAudio Member
 
diyiggy's Avatar
 
Join Date: Jan 2019
Thank you so much AllenB,

I saw this option, does it mean one have to use a tool to capture the measurment of the driver from a mic or tool like the Dayton driver measurement thingy ?
  Reply With Quote
Old 24th February 2020, 11:59 PM   #5
AllenB is offline AllenB  Australia
diyAudio Moderator
 
AllenB's Avatar
 
Join Date: Oct 2008
frequency amplitude R//C serie correction
What is your tweeter? Maybe I could help with the impedance file.
  Reply With Quote
Old 25th February 2020, 12:57 PM   #6
diyiggy is offline diyiggy
diyAudio Member
 
diyiggy's Avatar
 
Join Date: Jan 2019
Vifa AC25SG05, but how do you generate this impedance file ?
Thank you AllenB, there is no real needs so please don't waste time. It's more about to understand about such R//C in serie behavior on the frequency curve. So I undestand the resistor is about the spl correction, but I just don't understand the C value which is I assume to be the starting corner of the climbing frequency... Maybe if I enter the C value in a first order on line calculator it may give the frequency where it starts ? the low end being the tweeter high pass filter before this serie R//C?
Or learn to generats such files for this smart Xsim soft... I'm about to dig out threads about it, how to or manual if exists.
In real life I sure will need of complex tool as a LCR bridge handtool to measure speaker parts but I haven't, or build something with Arta to measure a driver out of the box...
In the meantime I really understand what is this serie R//C on a tweter as lifting up the SPL when the frequency is progressing towards the cut off means more tweeter cone movements, so more distorsion and less precision due to more amplitude in the Xmax range.
Of course I'm a noob and just read the Dickason cooking book so my basic understanding is low and just on the theory side...uh !
  Reply With Quote
Old 25th February 2020, 01:07 PM   #7
diyiggy is offline diyiggy
diyAudio Member
 
diyiggy's Avatar
 
Join Date: Jan 2019
... too bad it's not as simple as choosing an average nominal imedance on a datasheet or the voice coil Z...perhaps if the impedance curve was flat...
  Reply With Quote
Old 25th February 2020, 11:19 PM   #8
AllenB is offline AllenB  Australia
diyAudio Moderator
 
AllenB's Avatar
 
Join Date: Oct 2008
frequency amplitude R//C serie correction
You haven't shown your schematic. I guess that it is interesting what frequency the capacitor equals 1 ohm as well.
Quote:
Originally Posted by diyiggy View Post
how do you generate this impedance file ?
You can use a program to trace it for you, or you can type it by hand into a text editor while looking at the plot.
  Reply With Quote
Old 26th February 2020, 12:10 AM   #9
diyiggy is offline diyiggy
diyAudio Member
 
diyiggy's Avatar
 
Join Date: Jan 2019
Thank you AllenB !

I just have been understanding the need of accurate driver measurement on all the driver impedance curve from Pano member in a thread to play with such filters simulators. I naivly was thinking it was simplier and just had to enter the nominal impedance of the driver in a calculator...

He advised me the driver tester kit 2 from Smith&Larson, a fire and forget (pun intented) over the Dayton analyser V3. Cause it gives a zma file of the impedance on the whole frequency window of the driver !

I now understand why I didn't find an on line calculator for that.

I think my curiosity is definitly shooted by the price of such kit - while being not so much expensive at 150 usd- as I don't design speakers or often refurbishing old speakers. And having no issue with the filter but changing few lytics, it's more a no buy & forgett.

I will try to learn how to generate such text files from drivers curve & datasheet to understand the behavior of such filters...theorically. I eventually get such tools if I jump to play for real.

best regards

Last edited by diyiggy; 26th February 2020 at 12:12 AM.
  Reply With Quote
Old 26th February 2020, 12:55 AM   #10
AllenB is offline AllenB  Australia
diyAudio Moderator
 
AllenB's Avatar
 
Join Date: Oct 2008
frequency amplitude R//C serie correction
Quote:
Originally Posted by diyiggy View Post
the price
I measure impedance by connecting a speaker to my soundcard/computer. Nothing to buy. Just some wire and resistors. Free software is some of the best measurement software. Just saying..
  Reply With Quote

Reply


frequency amplitude R//C serie correctionHide 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

Similar Threads
Thread Thread Starter Forum Replies Last Post
Designing speakers for room correction amp = speaker frequency amplitude correctioni Tropic Multi-Way 0 23rd January 2019 12:20 AM
The room correction or speaker correction? What can we do with dsp power now availabl Raimonds Full Range 233 28th January 2017 07:51 AM
Amplitude and frequency distributions wanted DouglasSelf Solid State 13 18th September 2013 07:54 PM
Measuring and Correction of Frequency Response for Head-Phones tiefbassuebertr Headphone Systems 6 12th August 2012 04:39 AM
Martin Logan frequency correction??? MJ Dijkstra Planars & Exotics 50 21st October 2008 06:22 AM


New To Site? Need Help?

All times are GMT. The time now is 04:25 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright ©1999-2020 diyAudio
Wiki