OB Bass Excursion - Page 7 - 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 29th September 2012, 02:08 PM   #61
diyAudio Member
 
Join Date: Feb 2012
Location: Brisvegas
yep I have a Dayton omni mic, came up with what I think may be a new box type a Y box or butterfly box. Like a H box but not with parallel walls to cause reflection.

Plan to do it up in SketchUp tomorrow. Would look something like this...

|\____/|
|/-----\|
  Reply With Quote
Old 29th September 2012, 02:21 PM   #62
Banned
 
Join Date: Sep 2012
Yeah I like that.
  Reply With Quote
Old 29th September 2012, 02:27 PM   #63
diyAudio Member
 
Join Date: Dec 2011
Location: MO
I'm with studiotech and Murphys Law on this one. You gotta slow down a little bit and tinker with what you have. There absolutely no need to keep buying more drivers. The mids definitely need a baffle to come down to 100Hz and you still might need to EQ them or put in a battle step circuit passively to raise the bottom end up. I believe the SSpeaks could sound absolutely great (fuller) with just a few changes to your setup.

Those 18s that you have are killer, but once again, you have to either EQ them or put in a filter.

Have a look through my OB thread - I'm using 21s with a 30Hz low-pass (~12db/oct)! That might sound extreme, but they play relatively flat to 100Hz where a 10" mid takes over. The driver and baffle contribute to the crossover point, not one that I forced with circuitry. If I just run the mid and tweeter, the sound is just like are saying - thin. The woofers bring everything back in line.

Also - just remember that OB has horrible inefficiency for any kind of bass. Don't be surprised if you need to considerably up the gain on amplifiers or boost bottom frequencies (same effect). That'll get the LMS moving a bit more.

Additionally, if I'm running just test tones through the 21s, anything above 50Hz-60Hz has almost no movement. SPL is still displacement and frequency dependent - higher freqs need much less displacement for the same pressure level than lower ones. The OB rolloff means that your driver will have to move even more for the lower end.
  Reply With Quote
Old 29th September 2012, 02:34 PM   #64
puppet is offline puppet  United States
diyAudio Member
 
Join Date: Dec 2011
Location: The Dells, WI
I'll throw this out there too. I apply a low-cut filter @32hz w/a Q of 1.2-5 <-- you can play with that. Then a low shelving EQ target @80hz with a 12db slope gain of +5 <---- you can play with that. These are HP @116hz (4th order bessel)
  Reply With Quote
Old 29th September 2012, 02:40 PM   #65
diyAudio Member
 
Join Date: Feb 2012
Location: Brisvegas
Using the router I would cut the top and bottom butterfly pieces, and using a double 19mm MDF baffle board, it would be slightly longer than the centre section so a bit overhung both ends.

Dowels and glue, or screws coming up from the bottom would be spaced out and go the length of the baffle board.

The 4 Y end pieces would be cut at a 30 degree angle so at the baffle face they seamlessly join at a 60 degree angle. Screws coming up from the bottom again to hold Y boards in place.

Some custom [ shaped piece made from a router jig template would be stacked up both end to cap off the butterflies wings.

Top same as bottom and it should be stable enough to be free standing.
would look a bit like some heatsinks but with the ends capped off.

Edit:
might look more like a bow tie than butterfly wings.

Last edited by Silent Screamer; 29th September 2012 at 02:48 PM.
  Reply With Quote
Old 30th September 2012, 02:54 AM   #66
CLS is offline CLS  Taiwan
diyAudio Member
 
Join Date: Jun 2005
Location: Taiwan
This thread is growing so fast.

The woofer's Q is too low, you have to 'loosen' the motor.

Low Q Woofer in OB with High Zo Amp
  Reply With Quote
Old 30th September 2012, 03:01 AM   #67
diyAudio Member
 
Join Date: Jun 2004
Location: Orlando, FLA
Quote:
Originally Posted by CLS View Post
This thread is growing so fast.

The woofer's Q is too low, you have to 'loosen' the motor.

Low Q Woofer in OB with High Zo Amp
Stay on track Silent. Pretend you did not see this post, OK? It does not help you if you bought those 5400 also, ok? Remember, nice, tight, clean bass.
  Reply With Quote
Old 30th September 2012, 03:30 AM   #68
diyAudio Member
 
Join Date: Mar 2011
Location: Rochester, MN
Quote:
Originally Posted by Silent Screamer View Post
yep I have a Dayton omni mic, came up with what I think may be a new box type a Y box or butterfly box. Like a H box but not with parallel walls to cause reflection.

Plan to do it up in SketchUp tomorrow. Would look something like this...

|\____/|
|/-----\|
Those little angled walls aren't going to do anything for "reflection" at the frequencies it sees. What you will have is a 1/4 wavelength resonance based on the depth of the frame. A simple h-frame will give your bass drivers adequate baffle to account for the ob losses (eq will still be needed), is easy to build, and when sized properly the resonance can be moved up out of band.

And please, do more measurements!!!

Stay the course man!
  Reply With Quote
Old 30th September 2012, 03:47 AM   #69
diyAudio Member
 
Join Date: Jun 2004
Location: Orlando, FLA
BTW, CLS, I am apologize for seeming dismissive of your post. I did not intend that at all. It's just that Silent is getting so many differing ideas thrown at him at once and learning as he goes, I just want him to keep it simple here. Obviously, he does as he wants, just trying to help him get through it.

And I think he is settled on augmenting the OB with some TC 5400 in cabinets, so getting anymore out of the 5100 is not necessary, hence the extra complication of your techniques is probably not needed.

Greg
  Reply With Quote
Old 30th September 2012, 04:43 AM   #70
diyAudio Member
 
Join Date: Feb 2012
Location: Brisvegas
Quote:
Originally Posted by studiotech View Post
Stay on track Silent. Pretend you did not see this post, OK? It does not help you if you bought those 5400 also, ok? Remember, nice, tight, clean bass.
No haven't bought them yet, but they are part of a future plan once all of the main drivers are sorted, because I do eventually want to use all of this in a home theatre, but I want to supplement the speakers with sub type bass not try to add them to music. So I still need to get reasonably low out of the OB for music.

CLS low qts is one of the trade offs. I think I know what your saying if I could get the qts higher it would help, but as Greg says really not at that level where that is something that should be even considered for quite some time, perhaps way down the track.
  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
A bass-boost circuit for OB Roushon Multi-Way 40 5th October 2012 07:44 PM
OB bass with bass trap oon_the_kid Multi-Way 17 14th September 2012 12:23 AM
OB vs BR: driver excursion bvan Full Range 5 13th January 2009 07:20 PM
Big Bass Ob CLS Multi-Way 24 29th February 2008 12:27 AM
OB bass surprise bigwill Multi-Way 5 30th April 2007 10:24 PM


New To Site? Need Help?

All times are GMT. The time now is 11:59 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