Foam Core Board Speaker Enclosures? - Page 206 - diyAudio
Go Back   Home > Forums > Loudspeakers > Full Range

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 2013, 03:15 PM   #2051
xrk971 is offline xrk971  United States
diyAudio Member
 
xrk971's Avatar
 
Join Date: Oct 2012
Location: Virginia
Default Room Effects

I am pretty sure the frequency shelf near 300 Hz is a room-effect. I measured the frequency response again at 12 in away and got the same drop-off in frequency response when I mounted the driver on a piece of 24x36 in cardboard in an open baffle. I also used an old driver to make sure it wasn't a breaking-in effect which it is not. So the effect is clearly not a function of the cabinet design. The good news is that the Nautaloss speaker has an even flatter response than an open baffle - confirming my suspicion that the damped spiral absorbs the back wave like an infinite space.

So what we have here is a compact speaker that has a response like the front half of an OB without the huge OB size.

1/6th octave smoothing applied. Red is Nautaloss, Green is OB, Blue is OB with broken-in driver.

Click the image to open in full size.
Attached Images
File Type: png Nautaloss-OB-meas-12in.png (47.6 KB, 4849 views)

Last edited by xrk971; 12th December 2013 at 03:18 PM.
  Reply With Quote
Old 12th December 2013, 05:36 PM   #2052
diyAudio Member
 
Join Date: Oct 2002
Location: USA
This correlates with listening observations for the "Pluto" from here: Pluto + subwoofer
  Reply With Quote
Old 12th December 2013, 06:20 PM   #2053
xrk971 is offline xrk971  United States
diyAudio Member
 
xrk971's Avatar
 
Join Date: Oct 2012
Location: Virginia
Quote:
Originally Posted by skp112233 View Post
This correlates with listening observations for the "Pluto" from here: Pluto + subwoofer

What part of the Pluto writeup are you referring to? I am looking for confirmation of the drop at 300 Hz due to floor or wall bounce cancellation.
  Reply With Quote
Old 12th December 2013, 06:42 PM   #2054
diyAudio Member
 
Join Date: Oct 2002
Location: USA
I was referring to the similarity of responses for OB to the long stuffed spiral pipe and listening observations from the Pluto vs the Orion
  Reply With Quote
Old 12th December 2013, 07:26 PM   #2055
IG81 is offline IG81  Canada
diyAudio Member
 
IG81's Avatar
 
Join Date: Feb 2008
Floor/wall bounce usually shows up as a dip AFAIK, this ~15dB shelf is just plain strange. Have a different driver/speaker you can measure in the same spot?

IG
  Reply With Quote
Old 12th December 2013, 07:33 PM   #2056
xrk971 is offline xrk971  United States
diyAudio Member
 
xrk971's Avatar
 
Join Date: Oct 2012
Location: Virginia
IG,
the dip happens to combine fortuitously with a sharp edge in the response that is predicted in the simulation. The dip is just to the left of it, and the response is already falling off at -6dB/oct due to baffle step, so what you see is a notch to the left side of the 300 Hz 15 dB cliff. In otherwords, a well placed dip in an asymmetric baseline coupled with a sharp cliff on the right. That is my theory anyhow. An easier way is to change the speaker height or room location when measuring. I don't have another driver.

Here is a simplified model simulation of the Nautaloss without room reflections:

Click the image to open in full size.

Here is the sim with reflections:

Click the image to open in full size.

Here is the raw un-smoothed data for the response:

Click the image to open in full size.
Attached Images
File Type: png Nautaloss-Freq-12in-no-reflections.png (27.9 KB, 4468 views)
File Type: png Nautaloss-Freq-12in-with-reflections.png (28.8 KB, 327 views)
File Type: png Nautaloss-raw-meas-12in.png (45.8 KB, 330 views)
  Reply With Quote
Old 12th December 2013, 08:10 PM   #2057
diyAudio Member
 
BP1Fanatic's Avatar
 
Join Date: Jan 2009
Location: Columbus, Ohio
And for subwoofer???
  Reply With Quote
Old 12th December 2013, 08:12 PM   #2058
diyAudio Member
 
BP1Fanatic's Avatar
 
Join Date: Jan 2009
Location: Columbus, Ohio
Quote:
Originally Posted by xrk971 View Post
The horn really improves the intelligibility of human voices and I think might be a good candidate for a HT center channel. I just realized that I now have a full set of FC speakers that can make a nice HT setup. Not that I have a HT amplifier or tv to go with it

Use the two 0.53x scale Karlsonators for the front L R. The Nautaloss with tractrix for C. The 0.4x scale for the rear L and R.
I was replying to this post!
  Reply With Quote
Old 12th December 2013, 08:26 PM   #2059
xrk971 is offline xrk971  United States
diyAudio Member
 
xrk971's Avatar
 
Join Date: Oct 2012
Location: Virginia
I have an old bandpass sub but that won't cut it. I am currently developing my own sub design (a bass horn or maybe a tapped horn) and hope to share one day. For now, it doesn't matter as I don't have a HT receiver
  Reply With Quote
Old 12th December 2013, 10:05 PM   #2060
Carlp is offline Carlp  United States
diyAudio Member
 
Join Date: May 2006
Location: A New England
Quote:
Originally Posted by xrk971 View Post
The horn really improves the intelligibility of human voices and I think might be a good candidate for a HT center channel. I just realized that I now have a full set of FC speakers that can make a nice HT setup. Not that I have a HT amplifier or tv to go with it
Ha! I don't have HT amp or TV either, but I'm good with that. Especially with 7 and 10 y.o.s in the house. Someday maybe.

Now back to your regularly scheduled programming...
  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
Speaker damping: Foam or expanding foam akunec Multi-Way 4 11th February 2014 02:14 AM
Replace speaker foam with this odd material? flyingsquirrelman Subwoofers 7 25th July 2010 02:32 PM
concrete board for enclosures? alandarkdale Multi-Way 6 31st March 2007 09:35 AM
Foam core construction for subwoofers morbo Subwoofers 19 30th August 2005 09:09 PM
speaker foam dave k Multi-Way 2 24th June 2003 06:05 AM


New To Site? Need Help?

All times are GMT. The time now is 03:15 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