Do you find the bass changes as you move around the room differently to a boxed bass speaker? i.e. is placement and listening position critical for bass?
I've been thinking about having a go with a PA 15 or 18 inch bass driver crossed to an 8 inch Aerogel bass-mid then tweeter. The Eminence Beta 15 is easily had from Maplin, reasonably priced and looks well suited to OB with highish Qts. Shame resonance is only 35Hz though.
I've been thinking about having a go with a PA 15 or 18 inch bass driver crossed to an 8 inch Aerogel bass-mid then tweeter. The Eminence Beta 15 is easily had from Maplin, reasonably priced and looks well suited to OB with highish Qts. Shame resonance is only 35Hz though.
Hi guys. Due to Simon's continued ranting about the benefits of going ob, I too have decided to have a go.
Now I know that decent drivers are available from Mappo's, I would like to ask if the 12" Eminence Beta 12 is also suitable.
My wife will no-way allow a 15" monster driver to sit in the lounge, let alone two
I plan to use an FR125 as both mid and tweeter.
Cheers, Lee.
edit: Thanks for the inspiring and informative thread, guys.
Now I know that decent drivers are available from Mappo's, I would like to ask if the 12" Eminence Beta 12 is also suitable.
My wife will no-way allow a 15" monster driver to sit in the lounge, let alone two
I plan to use an FR125 as both mid and tweeter.
Cheers, Lee.
edit: Thanks for the inspiring and informative thread, guys.
Graham,
More people should pick up on the benefits of open-baffle (augmented by T-bass). I hope this thread gets some others interested, and of course I'll show them off in Chesterfield in about three weeks' time.
Rich,
The bass does indeed change as you move around, but I'd say the effect is 1/2 as pronounced as with monopole, if not even less. For me there's only one place to sit due to the size of the speakers and room and 1st order crossovers. But add a 2nd listener and he won't be disappointed by radically different bass.
Lee,
Come and listen before making your mind up one way or the other, you may not even like em much
Oh and tell Tina 15" wasn't too much the other night, so why can't it fit in now?
Seriously though, a 15" driver can fit on a 16" baffle mate....
But 2 x 12" would be a mean bass speaker anyway
I suspect 1 x 12" would be ok for lower levels even, but more than 0.8mm xmax would be useful...
Simon
More people should pick up on the benefits of open-baffle (augmented by T-bass). I hope this thread gets some others interested, and of course I'll show them off in Chesterfield in about three weeks' time.
Rich,
The bass does indeed change as you move around, but I'd say the effect is 1/2 as pronounced as with monopole, if not even less. For me there's only one place to sit due to the size of the speakers and room and 1st order crossovers. But add a 2nd listener and he won't be disappointed by radically different bass.
Lee,
Come and listen before making your mind up one way or the other, you may not even like em much
Oh and tell Tina 15" wasn't too much the other night, so why can't it fit in now?
Seriously though, a 15" driver can fit on a 16" baffle mate....
But 2 x 12" would be a mean bass speaker anyway
I suspect 1 x 12" would be ok for lower levels even, but more than 0.8mm xmax would be useful...
Simon
Hi Lee,
With some very careful cutting I have an 18" driver on an 18" baffle.
2x 12" wil give you a sensitivity lift, but the Beta's Fs is a little high for LF augmentation below that frequency.
A Beta-15A has Fs at 35Hz, so will get you lower/louder, but consideration is necessary relating to level matching with your main driver. What is your choice for main driver ?
Cheers ......... Graham.
With some very careful cutting I have an 18" driver on an 18" baffle.
2x 12" wil give you a sensitivity lift, but the Beta's Fs is a little high for LF augmentation below that frequency.
A Beta-15A has Fs at 35Hz, so will get you lower/louder, but consideration is necessary relating to level matching with your main driver. What is your choice for main driver ?
Cheers ......... Graham.
I plan to use the Creative Sound FR125 Full Range driver for mid & treble, hopefully making the crossover a touch simpler.
If possible I would like to use one 12" or possible 2 x 10" (which is preferable if possible) drivers for bass duties. I don't need high volumes as I currently live in a terraced house with neighbours on each side
I just thought, like Simon to have a go at ob and see if I like the sound. I have stuck the little FR's on ob's and as expected there'sno bass, but mid & treble detail are fantastic considering the driver.
Lee.
If possible I would like to use one 12" or possible 2 x 10" (which is preferable if possible) drivers for bass duties. I don't need high volumes as I currently live in a terraced house with neighbours on each side
I just thought, like Simon to have a go at ob and see if I like the sound. I have stuck the little FR's on ob's and as expected there'sno bass, but mid & treble detail are fantastic considering the driver.
Lee.
Thomo said:I plan to use the Creative Sound FR125 Full Range driver for mid & treble, hopefully making the crossover a touch simpler.
If possible I would like to use one 12" or possible 2 x 10" (which is preferable if possible) drivers for bass duties. I don't need high volumes as I currently live in a terraced house with neighbours on each side
I just thought, like Simon to have a go at ob and see if I like the sound. I have stuck the little FR's on ob's and as expected there'sno bass, but mid & treble detail are fantastic considering the driver.
Lee.
Lee,
Alternatively, buy (very, very cheaply) 8 of my 7" drivers and run them in series-parallel as I have done.
First listen and see if the bass is ok for your needs.
With 7" you can have a narrow baffle (good for imaging and neat)... something like 30cm wide with 15cm wings either side will get you into the deep bass territory, using T-bass of course.
Simon
Thanks Moon.
Can anyone help me design a passive notch filter to remove the dipole peak from the midrange response?
My corner cutaway should have reduced the peak substantially, and this is audible in the music, but I would like to see what happens if I reduce it further.
I can't find a calculator/tool for working out components anywhere.
Please see attached Edge simulation.
Simon
Can anyone help me design a passive notch filter to remove the dipole peak from the midrange response?
My corner cutaway should have reduced the peak substantially, and this is audible in the music, but I would like to see what happens if I reduce it further.
I can't find a calculator/tool for working out components anywhere.
Please see attached Edge simulation.
Simon
Attachments
Ok I found this:
http://www.diyaudioandvideo.com/Calculator/ParallelNotch/
Should do the trick nicely. I've realised (through what Edge suggests and from how it sounds) that I'm losing some lower midrange. I might try crossing my woofers in a little higher.
Simon
http://www.diyaudioandvideo.com/Calculator/ParallelNotch/
Should do the trick nicely. I've realised (through what Edge suggests and from how it sounds) that I'm losing some lower midrange. I might try crossing my woofers in a little higher.
Simon
Simon,
why don´t you optimse the response for your listening position? Simulating on axis for a mic distance of 100 m looks a bit odd ...
Thats obviously not where you are listening!
You can move the mic to the side and change the distance too.
Another hint: Don´t make baffles wider than 3 times the cone diameter. That helps to avoid that peak too.
Rudolf
why don´t you optimse the response for your listening position? Simulating on axis for a mic distance of 100 m looks a bit odd ...
Thats obviously not where you are listening!
You can move the mic to the side and change the distance too.
Another hint: Don´t make baffles wider than 3 times the cone diameter. That helps to avoid that peak too.
Rudolf
Rudulf,
Thanks for your suggestions, just in the nick of time! I was going to order parts for a notch filter I might not really need. I'd never really noticed the mic distance in Edge.
I'd much rather not put anything else in the signal path, it's already getting cluttered.
I'm now looking at putting the mid driver very close to the edge of the baffle, with cutaway, and trying a little compensation with a coil/resistor network to bring in the lower mid response... if necessary.
Simon /learning a lot
Thanks for your suggestions, just in the nick of time! I was going to order parts for a notch filter I might not really need. I'd never really noticed the mic distance in Edge.
I'd much rather not put anything else in the signal path, it's already getting cluttered.
I'm now looking at putting the mid driver very close to the edge of the baffle, with cutaway, and trying a little compensation with a coil/resistor network to bring in the lower mid response... if necessary.
Simon /learning a lot
I've realised it's likely to work better without a notch filter, just having the mid very close to the edge of the baffle. The missing lower mids will have to come from the woofer array.
Curve one is the simulated mid response in Edge, nice and close to the edge of a cut-off 30cm wide baffle.
The red line is the woofer response on a 60cm baffle (30cm + 15cm wing each side).
The two need to meld together using 1st order slopes mainly, and bear in mind the woofer response is altered by T-bass, so shouldn't actually dip anything like the sim shows.
Simon
Curve one is the simulated mid response in Edge, nice and close to the edge of a cut-off 30cm wide baffle.
The red line is the woofer response on a 60cm baffle (30cm + 15cm wing each side).
The two need to meld together using 1st order slopes mainly, and bear in mind the woofer response is altered by T-bass, so shouldn't actually dip anything like the sim shows.
Simon
Attachments
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