Hornresp - Page 144 - 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 8th October 2010, 07:35 PM   #1431
diyAudio Member
 
Join Date: Nov 2003
Location: California
I did a quick model in hornresp, and it looks like you should get strong response from ~1kHz down to 300Hz on axis with the highs rolling off. Since this is not matching the results you're getting, I'd say the issue is the high frequency response of the speaker. I attached screen shots. The dark curve is on-axis, the lighter lower curve is constant directivity (power response).

I'd try applying eq and seeing if you can get the tonal balance to be what you want before you start swapping drivers. I'm not saying that is a final solution, but if you can't get the tonal balance right with this horn and this size driver in it, changing drivers won't make a big difference - they'd just change the eq you needed to apply to get to a given frequency response curve.

Edit - to expand on that a bit, if you can't get the horn to sound right tonally as is with eq, that could be because of the polar pattern. So if you change the driver for a new one that's the same size, then you won't be likely to change the polar pattern very much and thus the issue won't go away. What would more likely change is the frequency response without eq. Thus my suggestion to try the eq first. If the system sounds tonally right with the eq but you don't want to have the eq in there, then you could look for a different driver.
Attached Images
File Type: jpg djn1.jpg (38.8 KB, 214 views)
File Type: jpg djn2.jpg (55.1 KB, 211 views)

Last edited by John Sheerin; 8th October 2010 at 07:44 PM. Reason: clarification
  Reply With Quote
Old 8th October 2010, 08:15 PM   #1432
djn is offline djn  United States
diyAudio Member
 
djn's Avatar
 
Join Date: Oct 2004
Location: Waterford Michigan
Thanks John. Yep, I am not hearing that plot at all. Almost like the reverse of it. I agree with your assesment that if the geometry is bad, then a great driver will not make a difference.

I don't know if you can do this or I should say, if HR can do this, but if I used the 6.5" x 5.6" back (removed) then stuck a 12" (or what ever size driver would make a 2:1 compression ration) on the back with a back chamber would it work as a midbass horn better than full range OB/horn.

Thanks again.....that reverse of what I am hearing plot stumps me.

Edit: I wonder if I put a back chamber around the driver if it would change things much.
  Reply With Quote
Old 8th October 2010, 08:24 PM   #1433
diyAudio Member
 
Join Date: Nov 2003
Location: California
Hornresp doesn't account for cone breakup, so it's not completely unexpected that the results don't match exactly in cases like this. However typically you use a horn like this to bring up the low end of a fullrange driver to match the higher level of the cone breakup, so it's weird that you aren't hearing that to some extent.

I suppose it depends on your definition of midbass, but I doubt you'd get it to go any lower than it does now. So it could potentially be a lower midrange horn with another driver but I'll leave that modeling to someone else.
  Reply With Quote
Old 8th October 2010, 09:03 PM   #1434
djn is offline djn  United States
diyAudio Member
 
djn's Avatar
 
Join Date: Oct 2004
Location: Waterford Michigan
Thanks John. Using a tone generator I match up the mid bass (200hz on up) to the "H" frame and I get a very smooth transition in that region, but when I step through the tones, at 3.5khz on up they scream. That being said, I can't really tell how the midbass sounds in the music. I don't have an eq to play with either. I can tell you that from 3.5khz on up sounds great. Clear, clean, fast, and with gret detail. It is just way out of whack.

Thanks for your help.
  Reply With Quote
Old 11th October 2010, 02:46 AM   #1435
djn is offline djn  United States
diyAudio Member
 
djn's Avatar
 
Join Date: Oct 2004
Location: Waterford Michigan
Another question. I modeled the horn with a 12" driver and for the most part got the same looking plot that John got when he modeled it with the FE126E.

So, my question is this: when it shows a upper end roll off why, in practice, do the highs still come through so strong and clean? (the highs go on way after the highend roll off shown in the HR plot.
  Reply With Quote
Old 11th October 2010, 02:49 AM   #1436
GM is offline GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
HR only calculates the horn's gain BW, not the driver's once it starts beaming.

GM
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  Reply With Quote
Old 11th October 2010, 07:34 PM   #1437
djn is offline djn  United States
diyAudio Member
 
djn's Avatar
 
Join Date: Oct 2004
Location: Waterford Michigan
Thanks GM. I've been playing at this hobby for quite a while now and these horns, straing as they are, sound very good. I just need to bring up the mids.
  Reply With Quote
Old 11th October 2010, 10:51 PM   #1438
GM is offline GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
You're welcome!

FWIW, for such apps, I use ~1 WL of its axial length as a good point to XO at or ~600 Hz for this horn which in this case pushes it high enough to put the highest power transients on the (mid) woofer. Combined with a 2nd order XO, the 15a's break-up modes will be flattened considerably to help boost overall performance, but my SWAG is that you'll either have to shelve the 126 or add a second 15a to pump up its efficiency.

WRT the 126, the lone measured response I have shows it to be a bit of a screamer with a single ear splitting spike up in our sibilance BW where it makes my teeth hurt, so it would seem that either listening as far off axis as the horn walls allow and/or EQing it would be worth a try. That, or make an expo horn to pump up the driver's lower response and choke down its HF somewhat. In any case, finding where that spike's coming from and damping it mechanically would be the #1 priority if it were mine.

GM
Attached Images
File Type: jpg Fostex_FE126E_spl_2.83V.jpg (22.5 KB, 147 views)
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  Reply With Quote
Old 12th October 2010, 03:15 PM   #1439
djn is offline djn  United States
diyAudio Member
 
djn's Avatar
 
Join Date: Oct 2004
Location: Waterford Michigan
Thanks for your thoughts GM. Yep, it is that peak and the general rise after 3.5khz that is the problem. The more I work with this horn, again, that I like very much, the more I think that I need to 1. find a driver that is more suited for this app or 2. figure out a step down for 3.5khz and above, or 3. whack off the back of the horns, attach a 12" woof and call it a true midbass horn. I have a number of tractrix horns that will so up from 600 - 800hz on up.

The other thing I thought about last night was to take the horn off the stand and drop the bottom lip down to the floor to pick up some re-enforcement of the floor.

I am bi-amping so I can bring up the woof seperatly. But are you saying that I should cross the 126 and 15a at 600hz? I have all the bits to do that, and think it would work given the 15a plot...below.

I have been a horn guy for the last 30 years and this is my first OB system. Maybe it is my age, but I really like the OB.
Attached Images
File Type: jpg alpha 15a plot.JPG (61.3 KB, 126 views)
  Reply With Quote
Old 12th October 2010, 04:03 PM   #1440
djn is offline djn  United States
diyAudio Member
 
djn's Avatar
 
Join Date: Oct 2004
Location: Waterford Michigan
One more thing, When you said "shelve" do you mean some kind of network that would bring down the highs? Something like a reverse CD comp network for Wave Guide horns?

Also, this being horns, what it help flatten them out to put a back chamber box behind the 126s?
  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
Hornresp Class FlipC Subwoofers 8 3rd November 2008 07:23 PM
Some questions about hornresp brsanko Full Range 4 18th October 2008 10:36 PM
Hornresp help / JX150 316a Multi-Way 0 11th February 2004 04:56 PM


New To Site? Need Help?

All times are GMT. The time now is 04:37 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