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

Modular active 3 way - work in progress
Modular active 3 way - work in progress
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 6th September 2018, 02:19 PM   #11
DonVK is offline DonVK  Canada
diyAudio Member
 
DonVK's Avatar
 
Join Date: Jan 2017
Location: Ottawa
Quote:
Originally Posted by Juhazi View Post
30cm distance is a bit too near to show baffle diffraction right. 1m is ok and with 4-5ms IR gating reliable from around 300Hz up. You can set gating longer and check when you start seeing reflections from ground, walls etc. more and more.
Those type of measurements (room) are coming. I started close to check the drivers, XO electronics, and amps. Then I'll increase the distance to include more of the cabinet and room so I can keep track of what is causing the effect(s).

Quote:
Originally Posted by Juhazi View Post
Don, I'd like to see the bass LP slope a little softer below mid, you are attenuating cone beakup too much? WM xo could be lower too, around 400Hz? Distortion of mid alone tells more of our possibilities with it.
The active XO is a vanilla SK LR4. I changed the XO points to better spread out the 10 octaves into 4 segments. There was a little further adjustment because I wanted to compare a 3" cone to a 2" dome midrange. Dome midranges need to be crossed a little higher >500Hz, so I moved it up to 725Hz for design margin. The distortion of this PC83, in a sealed box, starts to climb at <200Hz so it's certainly possible to cross lower but then I'd still have a problem getting a dome to go that low.

The woofer is small (6.5" paper) and it will go to 725Hz easily. The attached pic is the driver nearfield measurement in a BR cab with passive LR2@3Khz (both from another project). This thread's modular active design uses a sealed box and it has a combination of acoustic tile, fibreglass and poly fill.
Attached Images
File Type: jpg TC6028 (in BR cab).jpg (93.5 KB, 195 views)
  Reply With Quote
Old 6th September 2018, 02:37 PM   #12
DonVK is offline DonVK  Canada
diyAudio Member
 
DonVK's Avatar
 
Join Date: Jan 2017
Location: Ottawa
Quote:
Originally Posted by Boden View Post
Hello Don,


Those results are very good indeed, if not exceptional, for a textbook active filter without any delays or corrective building blocks.
Thanks. The vanilla XO filter is just used as a bulk frequency divider that can be driven from 2ch stereo. It should be possible (easy?) to select drivers that are flat in a very limited range (2.5 octaves) and that don't require any nearfield corrections other than sensitivity differences.

Corrections are coming . The IR and step responses for LR4's are not pretty and will be corrected using DSP FIR filters. The room EQ will also be done via DSP. They get developed on a PC but their final home is the RPI3B (via Ecasound and BruteFir).


Quote:
Originally Posted by Boden View Post
Kindly requested: Could you attempt to create 4th order LR target slopes in XSim to overlay over your actual SPL slopes in order to check how close the actual SPL slopes/output matches the target?


Regards,
Eelco
Yeah, I like overlays too, so I can try to add them. I think RePhase can create them and export to REW. I can also try REW export to Xsim to see what way is easier for me.
  Reply With Quote
Old 6th September 2018, 02:40 PM   #13
wintermute is offline wintermute  Australia
just another
diyAudio Moderator
 
wintermute's Avatar
 
Join Date: Aug 2003
Location: Sydney
Modular active 3 way - work in progress
__________________
Any intelligence I may appear to have is purely artificial!
Habour Side Events (Sydney).. Photography (another hobby)
  Reply With Quote
Old 6th September 2018, 02:50 PM   #14
Juhazi is online now Juhazi  Finland
diyAudio Member
 
Juhazi's Avatar
 
Join Date: Mar 2007
Location: Jyväskylä, Finland
So, if you can eq and fir only the signal before xo unit, you are in trouble, brother!
__________________
Radical activist AINOgradient speaker project
  Reply With Quote
Old 6th September 2018, 03:13 PM   #15
DonVK is offline DonVK  Canada
diyAudio Member
 
DonVK's Avatar
 
Join Date: Jan 2017
Location: Ottawa
I'll need more convincing of that Corrections are done on conventional speakers all the time because they are the majority of speakers. If I find a problem I can't correct I am willing to try a DAC + DSP XO per driver.
  Reply With Quote
Old 6th September 2018, 05:16 PM   #16
Juhazi is online now Juhazi  Finland
diyAudio Member
 
Juhazi's Avatar
 
Join Date: Mar 2007
Location: Jyväskylä, Finland
You'll get convinced soon!

The point is that drivers are not linear electrically or acoustically, not at least when measured off-axis. For example when mid and tweeter are crossed, each driver's response should follow optimal slope (and phase angle) to sum well (when using symmetrical phase linear xo). It is impossible to correct M and T individuallly, result is just "forcing" the spl measurement to look nice - sound doesn't improve much...

Fortunately today we have many alternatives to digitally divide and manipulate the original signal even in one box. And retail amplifiers are cheap as ...
__________________
Radical activist AINOgradient speaker project
  Reply With Quote
Old 6th September 2018, 07:40 PM   #17
DonVK is offline DonVK  Canada
diyAudio Member
 
DonVK's Avatar
 
Join Date: Jan 2017
Location: Ottawa
Default Phase correction - cleaning up the IR

RePhase and REW were used to get the phase response for the speaker and correct it. The EQ APO convolution engine was used, and the FIR has 16384 taps. The before (pic#1) and after (pic#2,3) are below.
Attached Images
File Type: jpg Phase correction is off - IR + Step.jpg (103.5 KB, 175 views)
File Type: jpg Phase correction FR.jpg (138.3 KB, 172 views)
File Type: jpg Phase correction IR + Step.jpg (101.4 KB, 164 views)
  Reply With Quote
Old 7th September 2018, 01:39 AM   #18
Bigun is offline Bigun  Canada
diyAudio Member
 
Bigun's Avatar
 
Join Date: Jan 2009
Location: Waterloo, ON or Herefordshire UK
Modular active 3 way - work in progress
wow, the before and after is quite dramatic.
__________________
"The test of the machine is the satisfaction it gives you. There isn't any other test. If the machine produces tranquility it's right. If it disturbs you it's wrong until either the machine or your mind is changed." Robert M Pirsig.
  Reply With Quote
Old 7th September 2018, 01:53 AM   #19
DonVK is offline DonVK  Canada
diyAudio Member
 
DonVK's Avatar
 
Join Date: Jan 2017
Location: Ottawa
Interestingly. The first time I saw the IR for a passive LR4 , I spent at least a week (with DIYaudio help) trying to determine what was wrong with it. It turned out it was suppose to look like that by design. I even measured 4 different commercial speakers that I own (and like) and all of them had very messy IR and steps.

Last edited by DonVK; 7th September 2018 at 02:03 AM. Reason: nothing
  Reply With Quote
Old 7th September 2018, 01:56 AM   #20
DonVK is offline DonVK  Canada
diyAudio Member
 
DonVK's Avatar
 
Join Date: Jan 2017
Location: Ottawa
Quote:
Originally Posted by Boden View Post
[snip]

Kindly requested: Could you attempt to create 4th order LR target slopes in XSim to overlay over your actual SPL slopes in order to check how close the actual SPL slopes/output matches the target?
How's this ?

Templates created using Rephase's filter impulse wav export to REW.
Attached Images
File Type: jpg Filter template overlay.jpg (108.3 KB, 153 views)

Last edited by DonVK; 7th September 2018 at 01:59 AM. Reason: template
  Reply With Quote

Reply


Modular active 3 way - work in progressHide 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
Active modular 3 way shared design? webby Multi-Way 6 22nd April 2016 06:55 AM
Work in progress... Asio4All Q pcb121055 PC Based 3 25th November 2011 05:59 AM
Gaincline Bi-Amp / Active Crossover - work in progress gainphile Chip Amps 10 6th January 2008 12:35 AM
BZLS work in progress till Pass Labs 10 26th February 2004 08:34 AM
Aleph 5 - work in progress SuppersReady Pass Labs 23 14th November 2003 10:40 PM


New To Site? Need Help?

All times are GMT. The time now is 09:30 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki