Dave; I'm building an MLTQWP - Bipolar and was wondering about the necessity of a brace between the drivers.
Are you using a brace between the WR125's, and if so what does the brace do for a bi-polar design?
Pete
Are you using a brace between the WR125's, and if so what does the brace do for a bi-polar design?
Pete
A brace is not necessary, but if you add it to more tightly couple the drivers the push-push effect will be greater, creating a better active vibration cancellation mechanism.
dave
I say, do it. I've been very pleased with the large amount of vibration reduction in the cabinet resulting from coupling the drivers. My last bipolar build has a nearly resonance free cabinet.
Thanks guys! What sort of brace do you use? The first thought that comes to mind is a 1" hardwood dowel with foam pads at each end---is that in the ballpark? Or would a spring loaded device be better?
Pete
Pete
You want maximum rigidity... hardwood is good, the foam only if it squishes down to nothing. An aluminum bar would be better (but usually not ready to hand)
dave
planet10 said:
I have been having a hard time trying to visualize this. Does anyone have any pictures? Is the bar just glued to the back of the speaker?
Here is a brace hot glued to one driver:
An externally hosted image should be here but it was not working when we last tested it.
This is the view before the brace added, but gives you an idea of the layout of the box
An externally hosted image should be here but it was not working when we last tested it.
dave
Some more from TLS.org...
http://www.t-linespeakers.org/FALL/bipolar/index.html
click on the pics to get full plans
and a gone nuts coupling -- partially possible because the driver was designed to be bolted to the back of the cab:
http://www.t-linespeakers.org/FALL/push-push.html
dave
http://www.t-linespeakers.org/FALL/bipolar/index.html
click on the pics to get full plans
An externally hosted image should be here but it was not working when we last tested it.
and a gone nuts coupling -- partially possible because the driver was designed to be bolted to the back of the cab:
http://www.t-linespeakers.org/FALL/push-push.html
An externally hosted image should be here but it was not working when we last tested it.
dave
Hello-
I'm wondering what the distance/power was on your frequency plot? I'm interested in using those drivers as well and wondering if 2 drivers in parrallel is enough to get to 90dB 1w/1m? Let me know if you would-
Thanks-
Ryan
I'm wondering what the distance/power was on your frequency plot? I'm interested in using those drivers as well and wondering if 2 drivers in parrallel is enough to get to 90dB 1w/1m? Let me know if you would-
Thanks-
Ryan
The measurement was taken at a distance of approximately 2 meters, on a forklift in the middle of a warehouse. 😀
Perhaps it would be better to address your concern directly.
Are you planning on driving the speakers with a one watt amp? Making basic assumptions having the two drivers in parallel in an enclosure is going to provide 87db sensitivity with one watt, conservatively. It could easily be more. I didn't apply 2.83 volts and use a SPL meter to see what the output was. It may be more appropriate to ask if the drivers can achieve the necessary SPL without suffering significant compression loss. If you're looking for 90db, that's no problem.
Are you planning on driving the speakers with a one watt amp? Making basic assumptions having the two drivers in parallel in an enclosure is going to provide 87db sensitivity with one watt, conservatively. It could easily be more. I didn't apply 2.83 volts and use a SPL meter to see what the output was. It may be more appropriate to ask if the drivers can achieve the necessary SPL without suffering significant compression loss. If you're looking for 90db, that's no problem.
Yea sorry a bit vauge there-
I am looking to pair some 125's as dedicated mids with a hiquiphon or possible morel supreme tweeter- I would prefer not to pad the tweeter down too much. The huquiphon OWII is about 90dB 1w1m and the 130 is 91.5. Anyway I know the math 2drivers= 3dB 3drivers =4.8dB 4drivers =6dB. And those figures should double given perfect acoustic and electrical coupling so 3dB conservative realworld maybe 4-5dB depending. . . That is why I was asking. Here is a better question-
How sensitive is your tweeter and did you have to pad it down at all?
Also I'm looking to easily achieve dB's in the 110-120's (for overhead purposes) but for that reason the wr125's would also be HP filtered at 200-300hz. And no I don't listen to music that loud- but these will be studio monitors and typical music with a band starts off with a very wide dynamic range. Studio monitors either need limiters (yuk) or rediculous amounts of headroom. Try plugging a bass guitar right into your system and you will see what I mean.
Also I could not find a power rating for these speakers- in your best estimation how much SS power can your system handle (with the 2 125's)?
I really appriciate your help-
Ryan
I am looking to pair some 125's as dedicated mids with a hiquiphon or possible morel supreme tweeter- I would prefer not to pad the tweeter down too much. The huquiphon OWII is about 90dB 1w1m and the 130 is 91.5. Anyway I know the math 2drivers= 3dB 3drivers =4.8dB 4drivers =6dB. And those figures should double given perfect acoustic and electrical coupling so 3dB conservative realworld maybe 4-5dB depending. . . That is why I was asking. Here is a better question-
How sensitive is your tweeter and did you have to pad it down at all?
Also I'm looking to easily achieve dB's in the 110-120's (for overhead purposes) but for that reason the wr125's would also be HP filtered at 200-300hz. And no I don't listen to music that loud- but these will be studio monitors and typical music with a band starts off with a very wide dynamic range. Studio monitors either need limiters (yuk) or rediculous amounts of headroom. Try plugging a bass guitar right into your system and you will see what I mean.
Also I could not find a power rating for these speakers- in your best estimation how much SS power can your system handle (with the 2 125's)?
I really appriciate your help-
Ryan
You may want to read the specs PDF on the Creative Sound website for the WR125.
http://www.creativesound.ca/pdf/WR125S.PDF
Dan W. ran several measurements including power stepping where he concluded that 3db compression occurs at ~99db so it's possible they could meet your requirements especially since you would be limiting them to the mid-band. His conclusion for a power rating was 35 watts. If you're not operating them below 200-300Hz they might meet that criteria also. I'm using a single WR125 as a mid-range in a setup where I've ran the system at near ear-bleeding levels with pretty good results.
http://www.creativesound.ca/pdf/WR125S.PDF
Dan W. ran several measurements including power stepping where he concluded that 3db compression occurs at ~99db so it's possible they could meet your requirements especially since you would be limiting them to the mid-band. His conclusion for a power rating was 35 watts. If you're not operating them below 200-300Hz they might meet that criteria also. I'm using a single WR125 as a mid-range in a setup where I've ran the system at near ear-bleeding levels with pretty good results.
I'm currently looking at a 2nd order XO solution to address the 7kHz bump. I'll assemble and test the XO this evening and post my results.
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