Cabinets effect (volume and baffle) on crossover - 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 23rd October 2012, 08:47 PM   #1
otlnoob is offline otlnoob  United States
diyAudio Member
 
Join Date: Oct 2010
Default Cabinets effect (volume and baffle) on crossover

hi all,

just a quick question regarding cabinet design. I currently have a crossover for an existing design using a .5 ft3 enclosure. However, I feel the cabinet is just too small for my application needs. So i have a few questions regarding a few scenarios and it's effect on the existing crossover.

Basically will the crossover need changed if I modify the baffle/port as:

a. higher, same width, same driver/port placement from top of baffle
b. higher and wider, same driver/port placement from top of baffle
c. same port, higher, wider and different driver placement
d. same height, width, driver placement, different port location

Thanks in advance for your feedback.
  Reply With Quote
Old 23rd October 2012, 10:16 PM   #2
Dissi is offline Dissi  Switzerland
diyAudio Member
 
Join Date: Sep 2012
Location: Winterthur
Without knowing any details of your speaker, I can only give a simplified guideline:

The crossover is most influenced by baffle width, less influence have baffle height and driver position and no influence has volume, port and port position.
  Reply With Quote
Old 24th October 2012, 12:41 AM   #3
diyAudio Member
 
Join Date: Feb 2002
Location: Western Sydney
changes in baffle width will affect the response, so If the crossover has baffle step incorporated, components which affect the baffle step frequency will need to be re-calculated. Baffle step freq = 115/width(metres)
__________________
Impedance varies with frequency, use impedance plots of your drivers and make crossover calculations using the actual impedance of the driver at the crossover frequency
  Reply With Quote
Old 24th October 2012, 04:50 AM   #4
otlnoob is offline otlnoob  United States
diyAudio Member
 
Join Date: Oct 2010
Dissi,

Thanks for reply - so I take it it is the external width of baffle, not the internal width. Can you explain why width of baffle is an issue and not height as the driver really has no idea which end is up??? (nor do i for that matter... )



Thanks again
  Reply With Quote
Old 24th October 2012, 07:12 AM   #5
diyAudio Member
 
voxxonline's Avatar
 
Join Date: Aug 2012
Location: Bexleyheath, Kent
Send a message via Skype™ to voxxonline
Guys
I have question:
While cutting mdf I made depth longer- it has increased volume by 2 litres.
I will cut it down to measurements, but just curious- what going to happen if volume stays the same?
Speakers: Mark K ER18DXT, 2 way rear ported
__________________
How to find time to finish my projects ?
  Reply With Quote
Old 24th October 2012, 11:17 AM   #6
Dissi is offline Dissi  Switzerland
diyAudio Member
 
Join Date: Sep 2012
Location: Winterthur
otlnoob:
Yes, we are talking of the external width. The influence of an edge depends on the distance to the driver. While in a tower it's almost only the width that matters, in a small 2-way the lower edge is also close to the woofer. Nevertheless I would extend the height of the box, keep the upper part of the baffle as it is, and add some inches at the bottom. Maybe shift the port into this area.

voxxonline:
Two litres more volume affects only the vent tuning, but the difference between 14.5 and 16.5 litres is not dramatic. If the speaker is mounted close to a back wall, the higher volume may even be better!
  Reply With Quote
Old 24th October 2012, 11:31 AM   #7
diyAudio Member
 
voxxonline's Avatar
 
Join Date: Aug 2012
Location: Bexleyheath, Kent
Send a message via Skype™ to voxxonline
Vent tuning means I need longer bass reflex port ?
And yes- speaker is close to the wall.
__________________
How to find time to finish my projects ?
  Reply With Quote
Old 24th October 2012, 11:34 AM   #8
diyAudio Member
 
voxxonline's Avatar
 
Join Date: Aug 2012
Location: Bexleyheath, Kent
Send a message via Skype™ to voxxonline
Design specs for port 50" 145 ", as I have deeper cabinet with bass reflex port not reaching optimal position in respect to the moving air ?
__________________
How to find time to finish my projects ?
  Reply With Quote
Old 24th October 2012, 10:08 PM   #9
otlnoob is offline otlnoob  United States
diyAudio Member
 
Join Date: Oct 2010
dissi,

Cabinet is fairly small, .5 ft3.

I re-ran some calculations for the cabinet and things look ok now. So i am fairly confident I'll not need a larger box. I've calculated there wont be ant standing waves below 3500 HZ, and I'm crossing over lower than that.

However, given how tight things are - I'll have to have port in the back, behind some other components. Basically it extends from back to about .5 in away from another device. Will that pose any port problems or is that enough clearance?

Becuase of this port is tuned a bit higher (5hz) than the drivers Resonant Frequency.

Also, looks like this driver will hit XMAX at 12.5 Watts at @ 25HZ, with SPL just hitting 100. See any issues with this?


Thanks Dissi
  Reply With Quote
Old 25th October 2012, 12:27 AM   #10
Dissi is offline Dissi  Switzerland
diyAudio Member
 
Join Date: Sep 2012
Location: Winterthur
As far as I know, 0.5" space at the end of the port is not enough and will probably affect the port function. I would not go below a distance equal to the port diameter, but I can't really tell, I only guess.

Xmax of every driver is limited, that's not an issue. 100 dB at 25 Hz even seem to be a bit optimistic. Most smaller drivers do not make 90 dB.
  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
What is the effect of Baffle Step on the Phase? Bricolo Multi-Way 4 25th July 2007 05:58 PM
what effect does baffle have on open-baffle system? kappa546 Multi-Way 6 24th January 2006 10:21 PM
effect of reorientating baffle and drivers? leadbelly Multi-Way 15 1st February 2004 03:26 PM
Effect from front baffle material? Oscar Multi-Way 22 14th August 2003 08:29 AM


New To Site? Need Help?

All times are GMT. The time now is 07:23 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