AMT sub - using dynamic woofer - Page 2 - diyAudio
Go Back   Home > Forums > Loudspeakers > Subwoofers

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 December 2010, 01:25 AM   #11
djk is offline djk
diyAudio Member
 
djk's Avatar
 
Join Date: Feb 2001
Location: USA
Click the image to open in full size.
__________________
Candidates for the Darwin Award should not read this author.
  Reply With Quote
Old 12th December 2010, 11:23 AM   #12
mige0 is offline mige0  Austria
diyAudio Member
 
mige0's Avatar
 
Join Date: Jan 2005
Location: Austria, at a beautiful place right in the heart of the Alps.
Default DFD / Deep Frame Dipole sub-woofer

DFD / Deep Frame Dipole sub-woofer



Summing on the effects of DFD / „Deep Frame Dipole“ sub-woofers there are obviously several mechanisms to observe.

Being a dipole loudspeaker, first to look at naturally is the typical dipole FR which basically is related to the separation distance.

In the context of aiming after high SPL output, the separation distance – in our case the depth of the „Deep Frame Dipole“ woofer - can and should be optimized with respect to the bandwidth of desire.
Meaning – for a given XO - we should put the first dipole peak slightly (˝ to 1/1 octave possibly) above XO frequency, as this directly affects the attenuation at the lower end of the bandwidth related to the well known comb filter effect seen in the green traces.
Comparing the Ripole speakers – stacking side by side versus stacking one behind the other – shows most clearly what to gain.

Another effect entering the picture with DFD woofers is that we basically create sort of pipe / transmission line / quarter wave speaker as well.
Here a cute little trick comes in handy to upshift pipe-peaking.
Comparing the N-frame and the Ripol (depth-stacking) shows most clearly that with conical pipe we get the nasty peak out of bandwidth.
This is a nice benefit in balancing bandwidth restrictions due to dipole behaviour and due to pipe behaviour.

The last effect that is easy to observe is kind of suck out + some loading occurring with the Ripols.
Mainly the sensitivity at middle frequencies is lowered, giving a more flattish FR in this area, and also the low and lowest department is pushed a few dB.
Sadly this comes at the expense of heavy peaking. Unfortunately, my first guess that distributed arrangement of speakers in the pipe will prevent the pipe from peaking, did not hold


All in all - with respect to SPL maximization / volume minimization - we possibly can say that its best to make “Deep Frame Dipole” sub-woofer as deep as possible, keep the pipe in conical shape and stuff it with speakers.



Michael

Last edited by mige0; 12th December 2010 at 11:44 AM.
  Reply With Quote
Old 12th December 2010, 11:33 AM   #13
mige0 is offline mige0  Austria
diyAudio Member
 
mige0's Avatar
 
Join Date: Jan 2005
Location: Austria, at a beautiful place right in the heart of the Alps.
Default DFD / Deep Frame Dipole sub-woofer

Quote:
Originally Posted by sendler View Post
Excellent work! One pretty picture equals a thousand words including the sketchup shots. They make the layout instantly understandable. Which of the graphs, red or blue, will be more representative of the anechoic far field response?
Thanx.
The blue trace is what you are looking for *if* you are interested in anechoic far field response – but – as said in the intro posting – both FR are kind of academic, considering a typical in room listening scenario.


Quote:
Originally Posted by sendler View Post
How much does the dual ripol shake? Is the dipole distance "d" the same for a three port, vibration canceling dual ripol of the same footprint as the four port dual ripol?

These speakers were built first hand to get an impression of the effects that can be optimized.
As for shaking - you know I'm a fan of swinging speakers – I don't think its becoming a problem.


Quote:
Originally Posted by sendler View Post
Is the dipole distance "d" the same for a three port, vibration canceling dual ripol of the same footprint as the four port dual ripol?
?? there is no three port speaker ??
The dipole distance is seen in the green traces and is also equivalent to the depth of the speakers.

All speakers have roughly 80cm separation, with the only exception of the ripole stacked side by side which is half of that: 40cm.


Michael

Last edited by mige0; 12th December 2010 at 11:44 AM.
  Reply With Quote
Old 12th December 2010, 11:35 AM   #14
mige0 is offline mige0  Austria
diyAudio Member
 
mige0's Avatar
 
Join Date: Jan 2005
Location: Austria, at a beautiful place right in the heart of the Alps.
Default DFD / Deep Frame Dipole sub-woofer

Quote:
Originally Posted by Zero Cool View Post
The Tymphany LAT subs work in a similar fashion to a AMT

https://www.madisound.com/store/prod...oducts_id=8311

The LAT is of the same idea but SPL capability is certainly not in the same league, I think


Michael

Last edited by mige0; 12th December 2010 at 11:44 AM.
  Reply With Quote
Old 12th December 2010, 11:42 AM   #15
mige0 is offline mige0  Austria
diyAudio Member
 
mige0's Avatar
 
Join Date: Jan 2005
Location: Austria, at a beautiful place right in the heart of the Alps.
Default DFD / Deep Frame Dipole sub-woofer

Quote:
Originally Posted by DQ828 View Post
I'm amazed your Dipole Peak is so so high when I calculate the peak for a 80cm H frame it is 160Hz yours appears to be over 200hz?

David

Well possibly I'm wrong - I calculated with 340m/s which gives 2.35ms time of flight for 0.8m which I dialed in and which equals roughly 210Hz ?

Anyway, the good thing on doing "comparative research" is that some 10-20% off do not affect validity of trends and conclusions to draw from.


Michael

Last edited by mige0; 12th December 2010 at 11:45 AM.
  Reply With Quote
Old 12th December 2010, 12:01 PM   #16
diyAudio Member
 
Join Date: Dec 2010
Location: The frigid midwest
Default Making my head spin...

Thanks for posting this... solidifying several ideas
that I have held a long time. great images...
  Reply With Quote
Old 12th December 2010, 12:42 PM   #17
Rudolf is offline Rudolf  Germany
diyAudio Member
 
Rudolf's Avatar
 
Join Date: Mar 2003
Location: Germany
Quote:
Originally Posted by mige0 View Post
I calculated with 340m/s which gives 2.35ms time of flight for 0.8m which I dialed in and which equals roughly 210Hz ?
Michael,
as with BR pipes, the geometric length of a H or U frame needs to be corrected by an end factor resulting in the effective length. MJK assumes the effective length to be = geometric length + 0.6 x reffective. reffective would be the radius of a circle with the same opening area as the H or U frame.
U and H Frames page 3

Rudolf
__________________
www.dipolplus.de
  Reply With Quote
Old 12th December 2010, 03:15 PM   #18
mige0 is offline mige0  Austria
diyAudio Member
 
mige0's Avatar
 
Join Date: Jan 2005
Location: Austria, at a beautiful place right in the heart of the Alps.
Quote:
Originally Posted by Rudolf View Post
Michael,
as with BR pipes, the geometric length of a H or U frame needs to be corrected by an end factor resulting in the effective length. MJK assumes the effective length to be = geometric length + 0.6 x reffective. reffective would be the radius of a circle with the same opening area as the H or U frame.
U and H Frames page 3

Rudolf
Thanx - and what would you calculate from that ?

Got confused for a moment ...

The green trace is the overlay of "inverse EQing" - this is not affected by any "opening factors" IMO (except I may add half of the mouth "diameter" to the path length probably).

Might be, far field is not "exactly" what the blue traces tell (its a work around after all) - but on the other hand - how *exact* do we need it finally in circumstances we never listen to ?

Might be - when temperatures are more friendly, I'll try to do a outdoor check, just to get a feeling ...


Michael
  Reply With Quote
Old 12th December 2010, 03:43 PM   #19
sendler is offline sendler  United States
diyAudio Member
 
Join Date: Aug 2004
Location: ny
Default Conical

Quote:
Originally Posted by mige0 View Post
All in all - with respect to SPL maximization / volume minimization - we possibly can say that its best to make “Deep Frame Dipole” sub-woofer as deep as possible, keep the pipe in conical shape and stuff it with speakers.
Any ideas on the cause of the dip/peak at 160Hz of the N frame? Aside from the bump at 90Hz, the deep RiPol looks better up to 150Hz as the big peak at 280 could be easily notched with digital EQ. Would you expect increasing the dimensions slightly to allow a golden ratio of 80*50*31 for each side of the deep ripol to smooth the wiggles 85-210Hz? And maybe a slight taper, somewhere in between straight and full conical which in this N frame is currently about 1:2. Taper at 1:5? Magnets at the throat or the mouth? As you can see I am very interested in a RiPol layout for two AE IB15s per side to be used under a swinging Eminence Kappalite 3012 mid with DCX and/ or lin phase pc cross.
__________________
Scott
  Reply With Quote
Old 12th December 2010, 03:54 PM   #20
sendler is offline sendler  United States
diyAudio Member
 
Join Date: Aug 2004
Location: ny
Default Lower

Quote:
Originally Posted by Rudolf View Post
Michael,
as with BR pipes, the geometric length of a H or U frame needs to be corrected by an end factor resulting in the effective length. MJK assumes the effective length to be = geometric length + 0.6 x reffective. reffective would be the radius of a circle with the same opening area as the H or U frame.
U and H Frames page 3

Rudolf
So this is good news. The in room bass extension may be even lower than the current blue traces show.
__________________
Scott
  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
ESS AMT 1 A (B, C, D, E) Monitor into ESS AMT 3 Rock Monitor cdfr Planars & Exotics 4 15th October 2010 03:38 AM
ESS AMT 1AM - original 12" woofer info FORNO Multi-Way 2 9th March 2010 10:33 PM
2-Way Speaker Project AMT and Watkins Woofer amper Multi-Way 3 7th February 2010 06:55 PM
ESS amt 1b replacement woofer and PR AudioGeek Planars & Exotics 1 7th November 2008 04:02 PM
ESS AMT-1D Woofer upgrade 1970 RS Z28 Multi-Way 2 4th October 2004 01:02 AM


New To Site? Need Help?

All times are GMT. The time now is 06:29 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