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

Dipole sub hole size
Dipole sub hole size
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 25th December 2010, 12:17 PM   #1
Deodato is offline Deodato  Netherlands
diyAudio Member
 
Join Date: Dec 2004
Location: Amsterdam
Default Dipole sub hole size

I am wondering what the minimum size for the two vents of a dipole sub should be, considering the phenomenon of the acoustic impedance.

Rod Elliot (sound.westhost.com) describes the implications for closed box speakers, giving their minimum cone sizes:

<quote>
...small cones (in small boxes) will be incapable of reproducing spectacular bass, regardless of the claimed Xmax of the driver. As an example (and please note that this is a very rough estimate only) the following table shows the expected minimum frequency of various sized drivers in a sealed enclosure having a small baffle, and radiating into space. Vented boxes work differently, but the vent area still limits the low frequency performance. A very large vent (needed for good performance and low noise at extra low frequencies) in an enclosure cannot be effectively driven with a small loudspeaker cone area.

Driver Diameter Minimum Frequency (-3dB)
200mm (8") 40 Hz
250mm (10") 32 Hz
300mm (12") 27 Hz
380mm (15") 21 Hz
450mm (18") 18 Hz

...
</quote>


Anybody?
  Reply With Quote
Old 25th December 2010, 01:16 PM   #2
Scott L is offline Scott L  United States
diyAudio Member
 
Join Date: Dec 2008
Location: Knoxville, TN
Dipole sub hole size
Default what ?

That information from Rod seems appropriate, but, I can not see the connection to your question (?)

And... I can not, for the life of me, figure out where 2 vents would go in a di-pole sub.
  Reply With Quote
Old 29th December 2010, 04:25 AM   #3
Deodato is offline Deodato  Netherlands
diyAudio Member
 
Join Date: Dec 2004
Location: Amsterdam
Consider a system with a 15" sub in an H-frame where the two ends are of course open, but by holes (vents..) of, say, 8". My question is, does the size of the holes now determine the lower frequency in the way described above, or is it only determined by the size of the sub driver itself. I understand these holes need to be of reasonable size in any case to avoid wind noise.
I'm unsure because the 8" holes would pretty much behave like 8" drivers in this configuration, but data from Axel Ridtahler's RiPole Subwoofer seems to suggest otherwise.

Last edited by Deodato; 29th December 2010 at 04:30 AM.
  Reply With Quote
Old 1st January 2011, 10:02 PM   #4
j.michael droke is offline j.michael droke  United States
diyAudio Member
 
Join Date: Jan 2009
Default Ripole analogy

Quote:
Originally Posted by Deodato View Post
Consider a system, ....but data from Axel Ridtahler's RiPole Subwoofer seems to suggest otherwise.
I'm well satisified with the sound of diy RIPOLE playing classical mucic and small group 50/60's cool jazz. The RIPOLE was constructed for a 12-inch diamater narrow driver and used biamped. However, the noise from the bass driver when really low notes are played (George Wright pipe organ, etc.), indicates a lack of driver Xmax. I believe Axel Ridthahler stated that the chambers and hence the openings were to be minimzed. I used 1&3/8-inch chambers ( by 13-inches )and the same size openings. Since the RIPOLE is a highly specialized type of enclosure, I doubt that RIPOLE info can be directly translated to other types of enclosures. best wishes for the frames you are working on, and hope you will post the resuts, and listening exteriences, ....regards, Michael
  Reply With Quote

Reply


Dipole sub hole sizeHide 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
Fostex 206e baffle hole size ljk11 Full Range 2 3rd January 2009 09:01 PM
Air Core inductor: Hole Size ! (waveforms shown) -_nando-_ Class D 67 14th January 2008 08:52 PM
bass matrix hole size....does it matter i4gotmyid Multi-Way 1 5th October 2007 03:27 PM
Help, Foxtex Fe207E FE206E hole size OzMikeH Full Range 5 6th April 2007 10:51 AM
PCB Hole Size ptah Parts 10 30th November 2006 01:51 AM


New To Site? Need Help?

All times are GMT. The time now is 05:14 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki