S15: Econowave DSP - a Constant Directivity vs Dipole study - Page 2 - diyAudio
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 December 2010, 08:41 AM   #11
DQ828 is offline DQ828  Australia
diyAudio Member
 
DQ828's Avatar
 
Join Date: Mar 2010
Location: Lake Macquarie, East Coast Australia
Quote:
Originally Posted by gainphile View Post
Actually in case someone turned the DSP off before the amps. It produces a whacking thump

The cap is basically a 300hz highpass 1st order passive xo:

amp ==> 68uf caps ==> tweeters

The implication is there will be phase shift so this needs to be accounted in the delay.

About Linkwitz transorm, yes it's one of the most powerful filter in existence. Even more important with dipoles. Have a read here:
Active Filters

And for miniDSP implementation, download the spreadsheet:
MiniDSP - Linkwitz Transform
Gainphile

The info says "First you have to determine the f(0) and Q(0) for your box." I don't have a box, I have a "H" frame, what should I do

David
  Reply With Quote
Old 26th December 2010, 09:06 AM   #12
diyAudio Member
 
gainphile's Avatar
 
Join Date: Dec 2007
Location: Melbourne the sunny city!
Email sent as it's a bit OT
__________________
http://gainphile.blogspot.com
  Reply With Quote
Old 26th December 2010, 11:13 AM   #13
diyAudio Member
 
john k...'s Avatar
 
Join Date: Aug 2004
Location: US
Quote:
Originally Posted by DQ828 View Post
Gainphile

The info says "First you have to determine the f(0) and Q(0) for your box." I don't have a box, I have a "H" frame, what should I do

David
You may be interested in this. The LT is not really the way to go with dipole woofers.

Also, you can download my ABC Diople for free here. It has a variety of filter calculators in the Excel spread sheet.
__________________
John k.... Music and Design NaO Dipole Loudspeakers.

Last edited by john k...; 26th December 2010 at 11:16 AM.
  Reply With Quote
Old 26th December 2010, 12:04 PM   #14
diyAudio Member
 
gainphile's Avatar
 
Join Date: Dec 2007
Location: Melbourne the sunny city!
The LT should be used to eq the driver. On top of that the 6db/oct dipole rolloff eq is still needed.
__________________
http://gainphile.blogspot.com
  Reply With Quote
Old 26th December 2010, 03:06 PM   #15
diyAudio Member
 
john k...'s Avatar
 
Join Date: Aug 2004
Location: US
Quote:
Originally Posted by gainphile View Post
The LT should be used to eq the driver. On top of that the 6db/oct dipole rolloff eq is still needed.
The problem with the LT in general is that it can not be used for all values of Q. The second thing is that if it is applicable and is used to shift the poles, the lower pole of 6dB eq must be well below the cut off frequency. It is basically what I suggest for drivers with Q > 0.5 and acceptable Fs and Qts for a 2nd order roll off but with the LT shifting Fs and Qts. The response rolls off 3rd order below the lower pole of the 6dB eq.

However, in general a dipole woofer should roll off at least 3rd order below the specified Fs to prevent excessive excursion below Fs.
__________________
John k.... Music and Design NaO Dipole Loudspeakers.
  Reply With Quote
Old 26th December 2010, 04:06 PM   #16
bwaslo is offline bwaslo  United States
diyAudio Member
 
bwaslo's Avatar
 
Join Date: May 2006
Location: Cinciinati, OH
Quote:
High:
High pass filter: 1khz LR4
Horn Notch: 1900hz, -4db, Q=1.4
Gain: -11db
Delay: 0.1ms
Tweeter protect: 68uF non-polar capacitor
Gainphile - how are you doing CD compensation (response lift starting at ~6kHz)? I don't see that in your settings.

Without that, the high end would seem pretty lifeless I'd think. Compression drivers have a natural mass rolloff at high frequencies, which normal horns tend to flatten due to their beaming. but constant directivity waveguides don't on their own). See the ewave passive crossovers, where they use a series resistor shunted by a cap to do this.
  Reply With Quote
Old 26th December 2010, 04:10 PM   #17
cuibono is offline cuibono  United States
diyAudio Member
 
cuibono's Avatar
 
Join Date: May 2006
Location: City of Angles
Nice work gainphile! I've been interested in this design for a while, and will someday build a set, maybe for a HT setup.

Could you post a regular polar graph? And have you considered adding an edge radius to the box and foam plug to the horn? I've read that these make a big difference, and people find the speakers sound less fatiguing.

BTW, what is your native language? That is interesting it doesn't have past-present-future distinctions.
  Reply With Quote
Old 27th December 2010, 12:28 AM   #18
CLS is offline CLS  Taiwan
diyAudio Member
 
Join Date: Jun 2005
Location: Taiwan
Well done!


Quote:
Originally Posted by gainphile View Post
...

DYNAMICS
One ascpect which I anticipated with monopoles is the "slam" factor. I expected that the CD will perform better in terms of dynamics, the snaps of snare drums, for example. But as I found out, this is not the case. The dipoles are actually more dynamic and snare drums and percussions are reproduced with better transients and gusto. The CD excel in low frequency slam like bass drums. No clear definite winner.
Score: DRAW
Maybe the dipole has smaller 'tail' after the impulse?

A well-designed sealed box usually has a tight and clean bass sound, might be somewhat muted when overdamped. It's a (pleasingly) surprise that a severely EQ'ed box has a good lower bass.

And, well, it can never be apple to apple in this comparison, but once you have bigger cone area for the dipole, it can also excel in low bass, at least for hearing. (good low 30's give a sense of 'very deep', under that, it becomes vibrations but not sound.... )

Also, on dipole, I found multiple subs benefit, too. I'm using 3 channels now. It's obvious better than 2.

Talking about the senses of dynamic and impact (or slam... etc) of bass sound, the most powerful one I've heard is horn bass - front loaded with sealed back chamber and full size mouth (not those commercial ones with severe truncation). Just overwhelming.

Interestingly, dipole bass (in its best condition) can deliver that kind of 'feel' - huge contrast, very fast rise and fall... Not the same level of sheer power, but the 'feel' can be very close
  Reply With Quote
Old 27th December 2010, 01:39 AM   #19
diyAudio Member
 
dantheman's Avatar
 
Join Date: May 2008
Location: Mountain View, CA
Great write up Gain! I had a similar experience with dipoles(coax pro 15 and compression driver) and direct radiators(Pro 10" and dome tweeter)--the dipole sounding more dynamic. However, when I went with a Dayton WG, D220, and Eminence Delta Pro 12A, in a similar fashion to the E-wave, dynamics seemed restored. I changed that woofer to a Peerless 10" and it seemed I again lost the dynamics but got a better sound balance, polar response, and deeper bass in return.

I wouldn't give up on either of your systems yet.

I'm curious as to what you make of the pseudo Pluto vs. pseudo EW vs. pseudo Note CD dipole. The Pluto essentially fits Dr. Toole's criteria fairly well. You're sort of in a unique position to have a toned down, but still awesome, version of Dr. Toole's findings/S. Linkwitz design, John K OB implementation, and Dr. Geddes perspective on loudspeakers at your fingertips.

Have you set those EWs up like Dr. Geddes recommends? The 45 degree cross. The most spacious presentation I've heard from a pair of loudspeaker requires that set up.

Great thread,

Dan
__________________
My Blog
My Music Recordings
  Reply With Quote
Old 27th December 2010, 03:54 AM   #20
diyAudio Member
 
gainphile's Avatar
 
Join Date: Dec 2007
Location: Melbourne the sunny city!
Quote:
Originally Posted by bwaslo View Post
Gainphile - how are you doing CD compensation (response lift starting at ~6kHz)? I don't see that in your settings.

Without that, the high end would seem pretty lifeless I'd think. Compression drivers have a natural mass rolloff at high frequencies, which normal horns tend to flatten due to their beaming. but constant directivity waveguides don't on their own). See the ewave passive crossovers, where they use a series resistor shunted by a cap to do this.
My implementation is active, so I simply notch the lower hump with appropriate cut and Q. It is very effective and easy to do.
__________________
http://gainphile.blogspot.com
  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
Constant Directivity Horn EQ Horizons Multi-Way 4 19th December 2008 11:41 AM
Constant directivity EQ Saurav Multi-Way 11 19th May 2008 02:41 AM
Constant directivity horn - or waveguide? hasselbaink Multi-Way 6 1st April 2008 01:24 PM


New To Site? Need Help?

All times are GMT. The time now is 02:25 AM.


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