Do back loaded horns invert the phase of the bass frequencies? I dont know why, but I am having so much trouble pairing a sub to my horns..
When I have the sub xover turned up to 200hz or so, having the phase to 0 is obviously correct. I switch it, and all the mid/bass disappears from my horns. But, I turn the xover down to 80hz or so and bass is a little weak.. I flip the phase switch to 180 and hear MORE bass.. (but.. maybe its canceling some of the lower midbass from my horns and the lower bass is just seeming louder.. I dont know!)
Any advice?
When I have the sub xover turned up to 200hz or so, having the phase to 0 is obviously correct. I switch it, and all the mid/bass disappears from my horns. But, I turn the xover down to 80hz or so and bass is a little weak.. I flip the phase switch to 180 and hear MORE bass.. (but.. maybe its canceling some of the lower midbass from my horns and the lower bass is just seeming louder.. I dont know!)
Any advice?
wicked1, I don´t always agree with hm (hi there - Hamburg got as lousy weather as Hannover at the moment?) but he is effing right - when using a single sub, 200 Hz is waaaay to high.
Plus, from what you write I suspect your sub Xover only cuts the sub off and leaves the horns to interfere in midbass...your room interacts with both and you get the puzzling results that cause you headache.
Plus, from what you write I suspect your sub Xover only cuts the sub off and leaves the horns to interfere in midbass...your room interacts with both and you get the puzzling results that cause you headache.
If you look at the following computer simulation
http://www.quarter-wave.com/Back_Door/BLH_Sections_Corner_7_03_09.pdf
starting on page 13 of the pdf file you will see the calulated SPL and phase for a back loaded horn. The driver, mouth, and combined SPL response are all shown.
http://www.quarter-wave.com/Back_Door/BLH_Sections_Corner_7_03_09.pdf
starting on page 13 of the pdf file you will see the calulated SPL and phase for a back loaded horn. The driver, mouth, and combined SPL response are all shown.
Hey, thanks MJK, actually, I have a pass to d/l your worksheets... This is so simple.. even my grandparents have to pair a sub to their system.. I didn't think I'd need the mathcad 
!
And no, I don't want my sub xovered at 200hz. I'm just trying to figure out the phase for the sub. When it's turned down to 80hz where it needs to be, I just can not tell which way the phase should go.. not at all.. My horns have faded by then, so there's not much frequency to cancel out.
So, I turn up to 200hz for what I would think would be an easier comparison. Which, it seems to be. Like I said in my first post I hear the frequencies getting canceled when the filter is turned up that high.
I'm just confused about why I seem to have the opposite results when I turn the filter back down low.
-Hey! and that mathcad sheet shows what I'm talking about! phase is flipped at just under 100hz and is that way till the low frequencies fade away from the horn!!!!!!!
I guess this is a little more complex than I thought.
Since I'm wanting to xover right where the phase changes, I think no matter what, I'll be canceling something..
well, maybe I'll spend some time modeling my exact speakers (just the fostex bk-16 kit from madisound) and see if it's the same.
!And no, I don't want my sub xovered at 200hz. I'm just trying to figure out the phase for the sub. When it's turned down to 80hz where it needs to be, I just can not tell which way the phase should go.. not at all.. My horns have faded by then, so there's not much frequency to cancel out.
So, I turn up to 200hz for what I would think would be an easier comparison. Which, it seems to be. Like I said in my first post I hear the frequencies getting canceled when the filter is turned up that high.
I'm just confused about why I seem to have the opposite results when I turn the filter back down low.
-Hey! and that mathcad sheet shows what I'm talking about! phase is flipped at just under 100hz and is that way till the low frequencies fade away from the horn!!!!!!!
I guess this is a little more complex than I thought.
Since I'm wanting to xover right where the phase changes, I think no matter what, I'll be canceling something..
well, maybe I'll spend some time modeling my exact speakers (just the fostex bk-16 kit from madisound) and see if it's the same.
Last edited:
Martin, I´m still somewhat unhappy with your worksheets. I do agree that the laws of physics are the same, but accepting that wavelengths in centimeters do the same slow somersaults as in inches...OK, the flak you got for your TL thing had other reasons, but you never shut up, willya please?
Pit I have no idea where your comments are coming from, I don't see much in the way of constructive inputs in your posts. But if I am being asked to shut up maybe it is time to go silent here.
>>> Pit I have no idea where your comments are coming from...
He's being sarcastic. I think it's fun.
>>> self-appointed gurus got shot to pieces because you applied math and phys instead of smoke and mirrors...
This is a compliment to MJK... and i think it's kinda clever actually.
>>> As to feet and inches - I still can´t think but metric...
I think Pit's hoping you can make an adjustment to your program for him.
>>> Plus, from what you write I suspect your sub Xover only cuts the sub off and leaves the horns to interfere in midbass...your room interacts with both and you get the puzzling results that cause you headache.
I agree with Pit here and would add you may have to fiddle with the placement of the sub. Mating sub to back horns is never easy. I had better results when my sub was very close to the rear wall. Even 4 or 5 inches seemed to make an audible enhancement. Try corner placement and set volume and frequency low and bring them up slowly, listen a little and adjust as you feel more or less bass is required in the mix. I hope you find the right balance for your room and system. You may give up altogether on the sub idea and find moving your BK16s around provide enough bass. Maybe try them in corners too.
I don't think Pit's got anything but love for this hobby and all the people who participate. This is just another example of why the written word sometimes creates a problem when nothing of the sort was intended.
Godzilla
He's being sarcastic. I think it's fun.
>>> self-appointed gurus got shot to pieces because you applied math and phys instead of smoke and mirrors...
This is a compliment to MJK... and i think it's kinda clever actually.
>>> As to feet and inches - I still can´t think but metric...
I think Pit's hoping you can make an adjustment to your program for him.
>>> Plus, from what you write I suspect your sub Xover only cuts the sub off and leaves the horns to interfere in midbass...your room interacts with both and you get the puzzling results that cause you headache.
I agree with Pit here and would add you may have to fiddle with the placement of the sub. Mating sub to back horns is never easy. I had better results when my sub was very close to the rear wall. Even 4 or 5 inches seemed to make an audible enhancement. Try corner placement and set volume and frequency low and bring them up slowly, listen a little and adjust as you feel more or less bass is required in the mix. I hope you find the right balance for your room and system. You may give up altogether on the sub idea and find moving your BK16s around provide enough bass. Maybe try them in corners too.
I don't think Pit's got anything but love for this hobby and all the people who participate. This is just another example of why the written word sometimes creates a problem when nothing of the sort was intended.
Godzilla
Martin, here I stand, throw rotten eggs at me.
I guess my English had a 180° phase shift there - my intention was to ask you NOT to shut up.
This goes back to when you first hinted at working on sheets for simulating horns and I asked you if your work on TLs hadn´t got you enough flames.
Well - the unlamented esoteric TL theories you put into cold and long forgotten graves still rest there and probably won´t see a resurrection whilst horns based on your math work exactly as predicted - QED.
If any offence was taken, please accept my sincere apologies.
Pit
I guess my English had a 180° phase shift there - my intention was to ask you NOT to shut up.
This goes back to when you first hinted at working on sheets for simulating horns and I asked you if your work on TLs hadn´t got you enough flames.
Well - the unlamented esoteric TL theories you put into cold and long forgotten graves still rest there and probably won´t see a resurrection whilst horns based on your math work exactly as predicted - QED.
If any offence was taken, please accept my sincere apologies.
Pit
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.