Hi And thanks for reading this thread
What are the t/s small parameters requirements, or any requirements at all, for an open baffle midrange driver.
I have an active sub going up to 120hz, then i am wanting a midrange to take over up to 3-4khz. I am wondering if there are any specs to take into consideration for best performance. Heard something about high qts but i think this is only for bass.
Also what do you think about a stiff suspension, as the trapped air within a sealed enclosure can push the driver back into the starting position ready for the next signal from the amplifier, whereas an open baffle driver does not have this support. Perhaps a stiff suspension may help to pull the driver's cone back a little more readily than a loose suspension.
What are the t/s small parameters requirements, or any requirements at all, for an open baffle midrange driver.
I have an active sub going up to 120hz, then i am wanting a midrange to take over up to 3-4khz. I am wondering if there are any specs to take into consideration for best performance. Heard something about high qts but i think this is only for bass.
Also what do you think about a stiff suspension, as the trapped air within a sealed enclosure can push the driver back into the starting position ready for the next signal from the amplifier, whereas an open baffle driver does not have this support. Perhaps a stiff suspension may help to pull the driver's cone back a little more readily than a loose suspension.
We are missing a lot of information before starting to suggest anything.
Size of the baffle, size of the room, size of the intended mid driver, passive or active XO, expectations and the kind of music the system will play.
But for starters, you will need quite a big mid driver with high-ish Qts if you expect it to reach 120Hz on OB.
Size of the baffle, size of the room, size of the intended mid driver, passive or active XO, expectations and the kind of music the system will play.
But for starters, you will need quite a big mid driver with high-ish Qts if you expect it to reach 120Hz on OB.
This is a misconception, the driver is under the control of the amplifier in both directions
If not already familiar with this work, it might help to check out MJKs papers on the larger field of OB Theory - there's more to it than just driver selection - and with your sub rolling off at 120Hz, you might need wider bandwidth than a midrange to get a successful blend. - perceval actually touched on that in his post above.
OB Theory
OB Theory
The baffle size i am thinking about is 40 inch square. The room is not good, it is the dreaded square shaped room with all sides approximatly equal, about 20 feet by twenty feet. Usually i play movies from bluray.
I have a few different drivers lying around and was wondering, if i could find the specs for them, perhaps they may be suitable for OB.
I have a few different drivers lying around and was wondering, if i could find the specs for them, perhaps they may be suitable for OB.
Read on Chris' link. It will help understanding a bit more about OB.
40 sq. inch will not go down to 120Hz.
Your best bet would be something like the Nola Brio. Part OB, part vented, best used with a sub.
40 sq. inch will not go down to 120Hz.
Your best bet would be something like the Nola Brio. Part OB, part vented, best used with a sub.
Only contributor I have read, in a very long time, with enough guts to post the truth. Thanks, you made my day !!
You could use a very large baffle to give low frequency extension, it wouldn't make for a good dipole speaker though, which I'm guessing is what goodguys is after.
If I might ask, What makes you think that an open baffle is a solution for your application ? Very few drivers are specifically *made* for an open baffle. Most drivers operate at their very best when mounted in an enclosure that prevents the front and back waves from meeting, and cancelling each other out. Having stated the obvious, it's also true that most boxes introduce vast colourations to the sound. Removing the box eliminates the boxy sound, but, at the same time introduces more problems that need to be addressed, which further complicates things. The trick is, to learn how to build a box (more properly known as an enclosure). If you are DEAD SET on the sonic signature from a di-pole speaker, do yourself a favour and buy a used pair of QUADS.
Where's the DIY fun in buying 2nd hand speakers? 😉
I have built my OB setup of a 15" woofer and 8" fullranger on an interesting baffle, and I am very pleased with the result.
I was also very pleased with the Brio clones, which is a mix of vented and OB drivers.
I have built my OB setup of a 15" woofer and 8" fullranger on an interesting baffle, and I am very pleased with the result.
I was also very pleased with the Brio clones, which is a mix of vented and OB drivers.
All speakers are open baffle to an extent because sound can travel through anything that contains atoms, ie anything that can be made to vibrate. When a drive unit pumps the air it vibrates the air molecules around itself which has a kind of domino effect, the sound it creates is conducted through the air and around the listening room via the movement of the air molecules in the listening room.
When the sound wave reaches the perimeter wall it vibrates the bricks the wall is made out of and conducts itself into the next room. This is why when you play any kind of music in one room someone in the next room can hear it.
That's why loading drive units into an enclosure does not prevent the front and back waves from meeting as previously stated. The sound simply vibrates the wooden enclosure walls and passes out into the listening room to cause destructive interference with the front cone radiation.
I addresed this a little a few years ago by making wall mounted speakers and using the room behind, which is the kitchen, as the enclosure, solved all the box and rear radiation problems, and certainly improved the listening experience.
For me i dunno, i just like the clean, 3-D kind of sound that open baffle gives. I did notice a loss of detail and slam when compared with sealed boxes, but it is something that i am prepared to put up with. It may be that i am intrigued by that airy kind of sound, when the rear radiation, delayed by a few milliseconds, and set up correctly, results in a sense of ambience, soundstaging and 3-D imagery.
Open baffle may be something worth looking into, it does produce a different kind of sound, just as paper cone drivers sound different from polypropylene drivers, which sound different from metal cones etc.
After all my years of experimenting if you have not at least looked at open baffles, you are doing yourself a disservice.
When the sound wave reaches the perimeter wall it vibrates the bricks the wall is made out of and conducts itself into the next room. This is why when you play any kind of music in one room someone in the next room can hear it.
That's why loading drive units into an enclosure does not prevent the front and back waves from meeting as previously stated. The sound simply vibrates the wooden enclosure walls and passes out into the listening room to cause destructive interference with the front cone radiation.
I addresed this a little a few years ago by making wall mounted speakers and using the room behind, which is the kitchen, as the enclosure, solved all the box and rear radiation problems, and certainly improved the listening experience.
For me i dunno, i just like the clean, 3-D kind of sound that open baffle gives. I did notice a loss of detail and slam when compared with sealed boxes, but it is something that i am prepared to put up with. It may be that i am intrigued by that airy kind of sound, when the rear radiation, delayed by a few milliseconds, and set up correctly, results in a sense of ambience, soundstaging and 3-D imagery.
Open baffle may be something worth looking into, it does produce a different kind of sound, just as paper cone drivers sound different from polypropylene drivers, which sound different from metal cones etc.
After all my years of experimenting if you have not at least looked at open baffles, you are doing yourself a disservice.
With the square room dimensions I guess you get some doubly nasty modes? Even more reason to go with a dipole -especially in the bass.
If you use a U-baffle and a good 15" or 18"driver you could get down to 30Hz and having clean lively bass. With a U-baffle you dont need a baffle the size of a door. The bass U-baffle need only have front dimensions that fit the driver.
For OB drivers its the bass woofer that needs to be special. It needs a generous linear one way Xmax eg 12mm, open back so it doesnt chuff and a low QTS would be wasted without a box. Ive only found one driver made for bass OB - Acoustic Elegance Dipole. One 15" will out perform two or four general woofers in free air making it cost effective.
Mid drivers and tweeters have less demands adapting to OB so try using what youve got. They may only need a small or even no baffle which would make for an elegant build. Try using the edge.exe program for designing baffles for the mid and tweeter. Try a sim with naked drivers eg for the tweeter use the mounting frame as the baffle and work out the actual driver diameter using the tweeter surface area.
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The main reason for putting a speaker in a box is to absorb the rear radiation, which it does very effectively
Yes, there does appear to be a bit of a trade off, I've found sealed boxes to perhaps be more precise sounding but rather two dimensional
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