Open Baffle Epiphany!
- Thread starter cptnCanada
- Start date
the hopefully famous martin king project 9 uses a 4" driver:
http://www.quarter-wave.com/Project09/Project09.html
he said the FE-108E Sigma is his favorite in this baffle
smaller driver is supposed to give better upper frequencies and wider dispersion (am i getting that right?). of course, LF is less important if you have bass assist.
http://www.quarter-wave.com/Project09/Project09.html
he said the FE-108E Sigma is his favorite in this baffle
smaller driver is supposed to give better upper frequencies and wider dispersion (am i getting that right?). of course, LF is less important if you have bass assist.
Poultrygeist
Lunatic Member
Have the guys at DIY tried dual Alphas with small FR's vs larger FR drivers or are they speculating? This is the reason I put more stock in someone's opinion if they can show me their build and tell me how it sounds.
I have pictures in my gallery of 4, 8 and 12 inch FR's in OB. Personally I like the 8's and 12's. 8's give a larger presentation than 4's. But my 12's offer a wonderful sense of scale and grandeur unmatched by smaller FR's. The trade off is there's less detail than with the 8's and 4's. Beaming has not been a issue with any of them. You could Google images of OB speaker and see which size drivers are favored.
Poultrygeist
Lunatic Member
FWIW MJK uses 8 inch Lowthers paired with double H-frames in his most current build.
cubdog
banging through drywall
I have know way of knowing exactly what their personal experience is. I made it clear that my preference for an 8 in driver was due to recommendations from those I trust. I also made it clear I'm a novice and that any and all recommendations are welcomed. It's a learning process for me and one that will take time. The more information I can gather and process will hopefully save me from a failed build.
cubdog
The issue of a smaller main driver raises the question of where the crossover is going to fall. The higher it gets, the more audible it's going to be. How are you going to deal with it? How well do the drivers blend together?
With my way of the multiple 8's, I just don't really need any cross so I sidestep the whole issue.
Remember the voice range. The 300 to 3K thing. That's the area to know the ear can detect our electronic tomfoolery the quickest.
EV3
With my way of the multiple 8's, I just don't really need any cross so I sidestep the whole issue.
Remember the voice range. The 300 to 3K thing. That's the area to know the ear can detect our electronic tomfoolery the quickest.
EV3
Poultrygeist
Lunatic Member
There are those who run their 8's straight from the amp without a crossover and use a plate amp with it's crossover to drive and filter the Alpha's.
If I were cubdog I'd try this simple approach first and if it's not to his tastes then add an electronic crossover. The plate amp would still be used to drive the Alpha's but it's crossover would then be set to max or switched off.
Poultrygeist
Lunatic Member
cubdog,
You could have your OB's custom built with a small interchangeable baffle to test different size FR's ala MJK's design. This way you could try different sizes and choose what you like best. It would also allow an easy upgrade for more expensive or new drivers introduced in the future.
The bottom part containing the Alphas would not be changed. Take the dimensions to any cabinet shop and they'll have no problem building them with your wood.
You could have your OB's custom built with a small interchangeable baffle to test different size FR's ala MJK's design. This way you could try different sizes and choose what you like best. It would also allow an easy upgrade for more expensive or new drivers introduced in the future.
The bottom part containing the Alphas would not be changed. Take the dimensions to any cabinet shop and they'll have no problem building them with your wood.
cubdog
banging through drywall
That's a good idea and one I've thought about. It would raise the build cost but might be worth it in the long run.
cubdog
tomlinmgt
Lunatic Member
In theory I totally buy this...but in practical application it seems an obstacle not so difficult to traverse. Look at the Econowave and other dynamic radiating/horn loaded compression driver 2-way designs. But I must admit, I do prefer the idea of one driver covering all of the critical mid range.
There are penalties to be paid all over the place....
Cone breakup
Intermod distortion
Crossover phase shift
Beaming
Polar pattern
Freq response abberations
Multiple amps
Extra wires
etc...
etc...
We just have to do our best to keep the count of issues as low as possible. Recognize what the issues are and how to best minimize them. And know what things bother us the most and the least in our own way of operating and the music we listen to.
IOW...pick your poison. :scratch2:
For me...the best success and most enjoyable listening comes from the wide as possible full range and only augmenting the extremes as necessary. I'm looking for as much impact, little distortion and the best timing as I can get and detail in the soundstage. I'll give up (when necessary and as little as possible) the ability for more extreme levels, ultimate flatness of response and the greatest extremes on the bandwidth. Different people are going to find different approaches for themselves to fit their choices.
EV3
Cone breakup
Intermod distortion
Crossover phase shift
Beaming
Polar pattern
Freq response abberations
Multiple amps
Extra wires
etc...
etc...
We just have to do our best to keep the count of issues as low as possible. Recognize what the issues are and how to best minimize them. And know what things bother us the most and the least in our own way of operating and the music we listen to.
IOW...pick your poison. :scratch2:
For me...the best success and most enjoyable listening comes from the wide as possible full range and only augmenting the extremes as necessary. I'm looking for as much impact, little distortion and the best timing as I can get and detail in the soundstage. I'll give up (when necessary and as little as possible) the ability for more extreme levels, ultimate flatness of response and the greatest extremes on the bandwidth. Different people are going to find different approaches for themselves to fit their choices.
EV3
The more people you ask the more different recommendations you will get. At some point there will be too many inputs to see a clear path forward. Since you do not seem to want to do the design work yourself maybe it would be best to pick an existing design and replicate it without any attempts at making inprovements. Start simple, you will learn a lot more by doing then by discussing on forums.
cubdog
banging through drywall
I'd love to do the design work myself I just have no experience. I am basically trying to go with an existing design. I just hit a roadblock with the FR selection.
cubdog
grafxdesin
Super Member
Well after reading through a good portion of this long thread, i'm pretty sure I now know what my next project will be. DIY open baffle speakers!
Ok, this is on page 33, so forgive me if this has already been covered. I have a pair of Morel Professional 12" coaxial drivers that are used for stages, studios and car audio. I was thinking of trying an OB setup just to see what they can do.
How do I determine the size of the baffle? Is there a formula to determine height and width? Is there a "cutoff" like with box speakers? Are there concerns with high frequency diffraction?
How do I determine the size of the baffle? Is there a formula to determine height and width? Is there a "cutoff" like with box speakers? Are there concerns with high frequency diffraction?
Those Morel's should be fun to play with OB. They probably are a lower Q design, so provided they have the xmax, you'll likely be wanting to use some form of EQ to bring up the bass.
The wrap around distance is going to determine where a 6db roll off is going to begin. Again, same on the eq need. Between the two, you're going to quickly run out of ability to drive it hard enough (power) and the driver have the ability to move far enough. Limiting how low you try to go plus how loud you listen are your way to deal with that.
As far as height, I'd suggest getting the tweeter up towards ear level while seated. So 30 to 38" to the center of the driver in this case. Positioning the driver lower will, depending on distance, add some floor reinforcement at some frequency. That may be desirable or not depending on where it falls and if you can listen to the perspective of being on the balcony looking down at the stage.
Using some heavy cardboard and playing might be a good way to start. Should be a lot of fun to play with and hear as an OB driver. Don't forget you can augment the lowest end with some other seperate sub if you have one around.
EV3
Awesome. Thanks so much. I have plenty of power available. That's not a problem. I was thinking, after reading a few more posts, of getting them about 30" off the floor, tilted, with hinges on the sides that I could use to tune the bass.
These speakers have large pleated paper surrounds and a good amount of travel.
The Morel tweeters are known for low crossovers. I think they are set to 2800 Hz with a small cap and the bass driver runs it's full range. But I also have some Morel passive crossovers that I can use to bring that down to 1800.
Should be fun!
Sent from my iPhone using Tapatalk
A nice design example is on eBay. Or a ready to go for someone in the DC area that's woodworker challenged .
http://www.ebay.com/itm/OPEN-BAFFLE-SPEAKERS-/121265331011?pt=Speakers_Subwoofers&hash=item1c3bfa1b43#ht_1336wt_1083
Uses a dual pair of Celestion woofers with the Dayton 8" full range driver above. Quite pretty and a good example of what can be done.
No affiliation. Just thought I'd point 'em out.
EV3
http://www.ebay.com/itm/OPEN-BAFFLE-SPEAKERS-/121265331011?pt=Speakers_Subwoofers&hash=item1c3bfa1b43#ht_1336wt_1083
Uses a dual pair of Celestion woofers with the Dayton 8" full range driver above. Quite pretty and a good example of what can be done.
No affiliation. Just thought I'd point 'em out.
EV3
nice looking build. don't know anything about those drivers. looks promising though.