Getting a bit more oomph out of the Eminence Beta 8A... - 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 18th December 2012, 04:04 AM   #1
diyAudio Member
 
Join Date: Nov 2007
Default Getting a bit more oomph out of the Eminence Beta 8A...

I've ordered some Eminence Beta 8 drivers for a small speaker project I'm working on at the moment, and I'm trying to come up with a design that gets a bit more bass out of them. What do you think of this?

HornResp data:
ID=28.00
Ang=4.0 x Pi
Eg=2.80
Rg=0.00
Fta=21.35
S1=390.00
S2=309.12
Par=35.20
F12=0.00
S2=309.12
S3=160.00
Par=64.90
F23=0.00
S3=160.00
S4=550.00
Par=12.00
F34=0.00
S4=0.00
S5=0.00
L45=0.00
F45=0.00
Sd=210.00
Bl=9.70
Cms=3.71E-04
Rms=1.33
Mmd=14.41
Le=0.49
Re=5.99
OD=1
Vrc=0.00
Lrc=0.00
Ap1=0.00
Lpt=2.00
Vtc=0.00
Atc=661.30
Pmax=100
Xmax=5.0
Comment=Eminence Beta-8A TL2

Response looks good down to 60 Hz. Power handling in-band seems to be around 25W, which is a pretty good match for what I intend to drive them with. Cabinet is actually going to be vented out the bottom and will contain one internal fold, which should allow me to put the driver almost exactly where HornResp suggests I should get the flattest response.

Thoughts?
Attached Images
File Type: jpg 20121217-beta8-1.jpg (95.3 KB, 200 views)
File Type: jpg 20121217-beta8-2.jpg (70.0 KB, 194 views)
__________________
www.diysubwoofers.org
  Reply With Quote
Old 18th December 2012, 05:04 AM   #2
diyAudio Member
 
Join Date: Jun 2007
Quote:
Originally Posted by Brian Steele View Post
What do you think of this?

HornResp data:
ID=28.00
Hi Brian,

ID=28.00 would indicate that you are using an older version of Hornresp. It may be worthwhile upgrading to the latest release, Version 30.20 (ID=29.00).

Kind regards,

David
__________________
www.hornresp.net
  Reply With Quote
Old 18th December 2012, 05:20 AM   #3
diyAudio Member
 
Join Date: Nov 2007
Quote:
Originally Posted by David McBean View Post
Hi Brian,

ID=28.00 would indicate that you are using an older version of Hornresp. It may be worthwhile upgrading to the latest release, Version 30.20 (ID=29.00).

Kind regards,

David
Thanks - I've just updated my copy to the latest version
__________________
www.diysubwoofers.org
  Reply With Quote
Old 18th December 2012, 01:01 PM   #4
diyAudio Member
 
Join Date: Feb 2004
Have you tried them in a bandpass horn?

You've looked at the group delay on this, and will be using some sort of time correction to delay your mids/highs.....right?
  Reply With Quote
Old 18th December 2012, 01:10 PM   #5
diyAudio Member
 
Join Date: Nov 2007
Quote:
Originally Posted by turbodawg View Post
Have you tried them in a bandpass horn?

You've looked at the group delay on this, and will be using some sort of time correction to delay your mids/highs.....right?
Perhaps I should have been clearer - I'm planning to use them as the bass-mid in a two-way system. I'm just trying to get a bit more low end out of them. The group delay rises to about 12ms at the low end in this alignment, but I suspect that really won't be an issue considering what it's going to be used for.
__________________
www.diysubwoofers.org
  Reply With Quote
Old 18th December 2012, 01:26 PM   #6
diyAudio Member
 
Join Date: Feb 2004
Quote:
Originally Posted by Brian Steele View Post
Perhaps I should have been clearer - I'm planning to use them as the bass-mid in a two-way system. I'm just trying to get a bit more low end out of them. The group delay rises to about 12ms at the low end in this alignment, but I suspect that really won't be an issue considering what it's going to be used for.
Where are you intending to cross these over, and what is the group delay at that frequency? That is the group delay to be concerned about.

Also, using a notch EQ on that 400hz peak is going to give you a pretty big phase/delay shift right in the low midrange, not good for vocal realisim.

Have you looked at using this in a ported horn?

What is driver for the highs? Some sort of full ranger, I presume?
  Reply With Quote
Old 18th December 2012, 02:40 PM   #7
diyAudio Member
 
Join Date: Jan 2008
Quote:
Originally Posted by Brian Steele View Post

Response looks good down to 60 Hz. Power handling in-band seems to be around 25W, which is a pretty good match for what I intend to drive them with. Cabinet is actually going to be vented out the bottom and will contain one internal fold, which should allow me to put the driver almost exactly where HornResp suggests I should get the flattest response.

Thoughts?
If the upper peak and dip is far enough away from the crossover point, it should do fine.

It will be fairly directional 150 Hz and higher, venting out the bottom would not be advisable unless the listeners are below the cabinet .

I'm using a Kappa 10 in a small ( 15" x 15" x 26.5") TH for a drum sub up to around 250 Hz where a pair of 5" come in, sounds pretty darn good, and gets loud.
  Reply With Quote
Old 18th December 2012, 06:11 PM   #8
diyAudio Member
 
Join Date: Nov 2007
Quote:
Originally Posted by turbodawg View Post
Where are you intending to cross these over, and what is the group delay at that frequency? That is the group delay to be concerned about.

Also, using a notch EQ on that 400hz peak is going to give you a pretty big phase/delay shift right in the low midrange, not good for vocal realisim.

Have you looked at using this in a ported horn?

What is driver for the highs? Some sort of full ranger, I presume?

It's going to be crossed over quite high to a piezo tweeter (yes, I'm trying to be as cheap as possible). Ignore the HornResp predictions above 200 Hz or so - there's going to be a bit of damping in the first 1/3rd or so of the enclosure, so those FR wobblies around 400 Hz are going to be significantly smaller than predicted in the graph, if they're present at all. Venting it downwards should reduce their impact on the FR as well. 150 Hz is a bit outside of the peak response from the vent, so perhaps venting downwards may not cause any problems. In any case, I'll consider some other designs.
__________________
www.diysubwoofers.org
  Reply With Quote
Old 18th December 2012, 07:21 PM   #9
diyAudio Member
 
Join Date: Feb 2004
Ahh, I see now. This is basicly a rear horn / transmission line. Sure, looks like it could work. How does it compare to a bass-reflex design of similar volume?
  Reply With Quote
Old 18th December 2012, 07:25 PM   #10
Pano is offline Pano  United States
diyAudio Moderator
 
Pano's Avatar
 
Join Date: Oct 2004
Location: Milliways
Blog Entries: 4
I never thought I'd see the Beta 8A in the Subwoofer forum. I think of it as an excellent midrange.

Will be interested to see what you get!
__________________
Take the Speaker Voltage Test!
  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
2-way with Eminence Beta-8A and CD+horn? Rullknufs Multi-Way 7 22nd July 2012 09:34 PM
FS Eminence Beta 8A pair nvrgdenuf Swap Meet 3 10th March 2010 01:58 PM
F/S Eminence Beta 8a pair nvrgdenuf Swap Meet 1 1st August 2009 09:59 PM
F/S Beta-8a nvrgdenuf Swap Meet 2 4th July 2009 07:54 PM
beta 8a rising response? AudioGeek Full Range 1 27th April 2009 08:45 PM


New To Site? Need Help?

All times are GMT. The time now is 03:19 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