Go Back   Home > Forums > Loudspeakers > Multi-Way

Multi-Way Conventional loudspeakers with crossovers

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 26th August 2013, 07:13 AM   #21
4real is offline 4real  Netherlands
diyAudio Member
 
Join Date: May 2004
Location: Arnhem
Quote:
Originally Posted by Rudolf View Post
If you can export your impulse response measurements as .wav files, I could turn them into polar plots or sonograms for you using ARTA.
I'll try to do that this week.


Quote:
Originally Posted by Juhazi
And what xo frequencies you use, what topology?
From the top of my head: 130Hz and 1600Hz, all 24dB/oct.

Quote:
I think it should be easy to eq the woofer even more (flat to 30-35?) , but perhaps at the expense of overall "efficiency" Be careful for not boosting low end, because without high-pass it leads to digital clipping in minidsp.
I catually already have a big problem with this. Since mid and low need a fairly big boost (I think the low end has about 20dB boost right now, probably far to much), I needed to turn down the levels of those channels significantly to prevent digital clipping. This has the nasty side effect of not being able to play very loud right now. The 0dB setting of the miniDSP is just not loud enough to make me fall of my chair

I think I'll need to make the amps with adjustable gain, so I can give every channel the most optimum gain possible. I guess, three variant should be enough: 1x, 2x, 4x. Currently I only have a unity gain LM4562 buffer in front of the L25D's because the miniDSP cannot drive the amp directly very well. It should be an easy fix to add a dip switch to change gain.

I also came up with an improved design yesterday. It should solve the problem of the vibrating bass section, but I can't seem to get a nice way of clamping the magnets without obstructing the NEO3. I came up with a different approach by clamping the mid/tweeter section, sort of like a H baffle. I don't like it yet however, so it needs more work. The bass section is now completely round, and will also be clamped and suspended between de sides using rubber o-rings (and some way to hold it together).

Click the image to open in full size.
Attached Images
File Type: jpg Desing2.jpg (34.1 KB, 677 views)
  Reply With Quote
Old 26th August 2013, 07:44 AM   #22
Juhazi is offline Juhazi  Finland
diyAudio Member
 
Juhazi's Avatar
 
Join Date: Mar 2007
Location: Jyväskylä
I use 4x10Hd too. Have you adjusted the dip switches inside the box? Mine came with low sensitivity input settings. Both input sensitivity and output level are selectable (for balance/unbalanced)! User manual http://www.minidsp.com/images/docume...r%20Manual.pdf

The side panel will harm your horizontal polars, original concept is much better! Does the Neo3 have it's back plate on - then it doesn't radiate backwards.

xo's are propably ok for this system. I expect there will be quite high energy above 1600Hz when mearured 15¤ and more sideways ( bump in power response). That can't be fixed electronically (4-way or tweeter with a horn is needed). The meaning of this remains a question and depends on your room too.
__________________
AES Associate Member / My DIY speaker history: -74 Philips 3-way, -82 Hifi 85B, -07 Zaph L18, XLS10+PR/Hypex, -08 CSS125FR, -08 Hifitalo AW-7, -08 TangBand FR, -09 MarkK ER18DXT, -13 PPSL470, -13 AINOgradient
  Reply With Quote
Old 26th August 2013, 08:40 AM   #23
4real is offline 4real  Netherlands
diyAudio Member
 
Join Date: May 2004
Location: Arnhem
Quote:
Originally Posted by Juhazi View Post
I use 4x10Hd too. Have you adjusted the dip switches inside the box? Mine came with low sensitivity input settings. Both input sensitivity and output level are selectable (for balance/unbalanced)! User manual http://www.minidsp.com/images/docume...r%20Manual.pdf
Yes I know. I didn't open the box yet, because default should be high sensitivity (so 2VRMS), and that would fit the 1.6V of my amp just fine. I'll have a look at the switches now though

Quote:
The side panel will harm your horizontal polars, original concept is much better! Does the Neo3 have it's back plate on - then it doesn't radiate backwards.
As I said, I don't like it either . I can make the side panels much lower, but that would make the top part flimsy again The Neo has it's back plate removed. If dipole, then all the way. It is also needed to cross the NEO that low. If I want to clamp the magnets without obstructing the tweeter, I'd need to go for a MMT, and go 4-way.

Quote:
xo's are propably ok for this system. I expect there will be quite high energy above 1600Hz when mearured 15¤ and more sideways ( bump in power response). That can't be fixed electronically (4-way or tweeter with a horn is needed). The meaning of this remains a question and depends on your room too.
I can imagine you are right there. The flat on-axis response yield in a fairly bright sound. I'd like it bit less bright, and I would expect it to be so judging by the response. Could I solve this by using an extra pair smaller mids to push the tweeter x-over point further up? It would be a 4-way SWMTMW then.
__________________
Do diamonds shine on the dark side of the moon?

Last edited by 4real; 26th August 2013 at 09:03 AM.
  Reply With Quote
Old 26th August 2013, 03:06 PM   #24
Juhazi is offline Juhazi  Finland
diyAudio Member
 
Juhazi's Avatar
 
Join Date: Mar 2007
Location: Jyväskylä
Yep, directivity control is very difficult with dipole systems (narrow passbands), sorry! This is why S Linkwitz, J Kreskowsky and Gainphile went 4-way - and me too with AINOgradient. Actually a 4-way with a horn-loaded tweeter.
http://www.diyaudio.com/forums/attac...high-ref-s.jpg

But you can do the waveguide trick instead and keep 3-way! This thread lifted up the 8" oval double waveguide with a ribbon tweeter. Waveguide helps with directivity and low-end extension both! Distance between mids will grow a little but it might be tolerable. The question is how low you can go with Neo3 openback (power handling, distortion)
My first wave guide speaker....lots of pics
__________________
AES Associate Member / My DIY speaker history: -74 Philips 3-way, -82 Hifi 85B, -07 Zaph L18, XLS10+PR/Hypex, -08 CSS125FR, -08 Hifitalo AW-7, -08 TangBand FR, -09 MarkK ER18DXT, -13 PPSL470, -13 AINOgradient
  Reply With Quote
Old 26th August 2013, 07:05 PM   #25
4real is offline 4real  Netherlands
diyAudio Member
 
Join Date: May 2004
Location: Arnhem
Well, a waveguide is not really a problem. I have the room for it, and I wasn't going to use the front plate anyway.

A 4-way design is just going to be to large, and also add extra cost. I guess a Neo 8 would be doable budget wise, but it doesn't really fit the visual design.

But I'll first do some more measurements, and then we'll see how large the problem really is.

Meanwhile, I can think about the final design some more
__________________
Do diamonds shine on the dark side of the moon?
  Reply With Quote
Old 27th August 2013, 07:52 AM   #26
diyAudio Member
 
StigErik's Avatar
 
Join Date: Feb 2008
I ended up with a 4-way as well, or you could call it a 3-way with an H-baffle subwoofer.

The main problem is to find a small enough dipole tweeter in order to maintain good directivity, but a tweeter small enough for 20 kHz does not exist. I used the Mundorf AMT2340 without frontplate. The directivity was good up to about 6 kHz, which is quite good.

A design like mine shown on the pic below will have good directivity in the horizontal plane, but the vertical plane is a total mess.

Click the image to open in full size.
__________________
dipoles dipoles dipoles dipoles dipoles dipoles dipoles dipoles and dipoles
  Reply With Quote
Old 27th August 2013, 08:45 AM   #27
Juhazi is offline Juhazi  Finland
diyAudio Member
 
Juhazi's Avatar
 
Join Date: Mar 2007
Location: Jyväskylä
StigErik, I have followed your projects for a long time. What is your personal opinion of the audibility of vertical variations and is there a "real" problem with vertical lobing/combing in these multiway speakers? Supposing we think in context of home environment, not concert venues/ long distance PA.

Like someone said earlier, lobing and specially directivity can be beneficial too, to minimize floor reflection eg. - the mostly used "beneficial effect" Your line of 4 woofers is a directivity cannon! Did you do it because of that or just for sensitivity/distortion management?
__________________
AES Associate Member / My DIY speaker history: -74 Philips 3-way, -82 Hifi 85B, -07 Zaph L18, XLS10+PR/Hypex, -08 CSS125FR, -08 Hifitalo AW-7, -08 TangBand FR, -09 MarkK ER18DXT, -13 PPSL470, -13 AINOgradient
  Reply With Quote
Old 27th August 2013, 09:14 AM   #28
diyAudio Member
 
StigErik's Avatar
 
Join Date: Feb 2008
Well, why do we seek good directivity to begin with? If it didn't matter, all we should do is optimize the on-axis response....

Yes I do think uneven off-axis response is audible, not just in the horizontal plane, because the room reverb/decay will be less linear.

But the biggest challenge is the floor and ceiling early reflections. These are difficult to avoid, and difficult to treat (especially the floor). They will not be anyway close to linear in frequency response either, and will in any case cause coloration and strong comb filtering of the response at the listening position. That is why I prefer a line source, because it practically eliminates the floor and ceiling reflections.

The four woofers in my design show above has no directivity benefit, since I XO at ~500 Hz. It does not start to beam in the vertical plane until above the XO point. I used four woofers to get better sensitivity and more SPL, and of course less distortion. I also reversed two of the woofers and one midrange to get reduced even order distortion, as shown below.

Click the image to open in full size.
__________________
dipoles dipoles dipoles dipoles dipoles dipoles dipoles dipoles and dipoles
  Reply With Quote
Old 27th August 2013, 10:00 AM   #29
Rudolf is offline Rudolf  Germany
diyAudio Member
 
Rudolf's Avatar
 
Join Date: Mar 2003
Location: Germany
Quote:
Originally Posted by Juhazi View Post
Yep, directivity control is very difficult with dipole systems (narrow passbands), sorry! This is why S Linkwitz, J Kreskowsky and Gainphile went 4-way - and me too with AINOgradient.
Directivity control in dipole systems is easy as pie - if you stick to the rules! Admittedly those rules don't allow massive cone areas in a 3-way system. When people go for 4-way systems, this is mainly driven by high SPL demands on their behalf.

4real has this problem in the midrange section. It always shows first in the midrange section. I compare his measurement with the Edge sim (red line) of his baffle:
midrange comparison.gif
We can easily identify the dipole peak and dip region. From theory we know that the off axis response curves will converge between the peak and the dip - resulting in a blooming of the off-axis response. It is easy to predict a rather blatant response for the area around 2 kHz.

The best remedies would be to either
- cross below 1.5kHz (which either demands an AMT tweeter or leads to a 4-way system) or
- reduce the size of the midrange drivers to (baffleless)12 cm instead of the HDS180. Obviously this solution would reduce the maximum SPL capability.

BTW: I see a reverse problem for the crossover between woofer and midrange. The upper frequency limit for the woofer needs to be exploited. Presently the crossover point is way too low for a 3-way system.

Rudolf
__________________
www.dipolplus.de
  Reply With Quote
Old 27th August 2013, 10:34 AM   #30
4real is offline 4real  Netherlands
diyAudio Member
 
Join Date: May 2004
Location: Arnhem
Hmm..

I could imagine a design like this SWWMT. This would simplify construction a lot, and retain the visual design somewhat. I would loose the MTM. The question then would be what mid I would add? I might have some candidates:

- Visaton TI100
- Peerless/Vifa NE123W-04
- B&G NEO8 (S). This one is a bit harder to make fit in visually
__________________
Do diamonds shine on the dark side of the moon?
  Reply With Quote

Reply


Hide 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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
OB "omni" experiment Kjeldsen Multi-Way 85 8th April 2014 11:25 AM
S9 OB - Revisiting narrow baffles gainphile Multi-Way 30 3rd June 2011 06:27 AM
My current OB experiment Saurav Multi-Way 15 27th August 2010 08:43 PM
SDA in OB experiment Kensai Full Range 0 20th February 2007 06:50 PM
Experiment in single driver OB mashaffer Full Range 9 13th May 2006 04:17 PM


New To Site? Need Help?

All times are GMT. The time now is 01:52 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2