Ah, that does make it more difficult. You might try the technique used to make templates. You trace out the shape in pencil then cut close to it with the jig saw. Once the basic shape is cut you file, scrape and sand down to the line. It's tedious, but it gets you there. It works well enough for me with 1/2" MDF.
That's exactly what I did, built two jigs, one just for drawing circles, a second one that fit my jigsaw. I can make a 6" wide circle and then sand down the edges or use a rasp to get the edges reasonable. It's the inner 3" circle on the 1/4" baffle plate that is killing me. I can't cut it with a jigsaw so I end up using a dremel with a cutting tool to cut the inner circle out but I just don't have the control to stay near the line and every time I try to get the inner circle close to the line I end up screwing up and going over it then it becomes a throwaway. I drilled a 5.5" jigsaw hole in the baffle for the vifa and my plan is to bolt the vifa into the back of the plate and then clamp/glue it over the 5.5" hole.
If you are patient, you could do it in the fred flintstone way: deill holes along the 3“ circle, hammer out the faps with a chisel or even a screwdriver, and adjust with a rasp. (Depending the roughness of your dremel, you will get better results because it’s slower). Refinfe with sandpaper weapped around a stick...
I was planning to build the latest Ultra with the fancier wings, but I am very intrigued by the thought of a new/improved version! My timeline is probably about a year out due to the amount of house projects (moved a few years ago), so the timing might work out well for the new beasts!
Thanks!
Roger
Apologies for not correcting this fat-fingered blabbering!
I could totally understand what you were saying and it made sense but luckily I found the solution. I grabbed some sanding attachments for the dremel and now I can just get 'close' with the roto cutting tool and then sand off all the rough edges with the standing disc at high speed, then I can switch to low speed to even them all out and then finish up with 220.
I checked my hole saw kit and it only goes to 2.5 that's what led to my using the dremel with the rotozip kit. Now that I have the sanding pieces this has become much quicker/easier!
Okay, I finally have the drivers mounted on the back of 1/4" 6" diameter baffles and I have a 5.5" vifa cutout. I think I saw a recommendation to put them back on slightly offset rather than centered over the vifa cutout to keep it from being totally symmetrical, was that an accurate statement?
Also is the woofer center 13" up from the bottom set in stone or are there no deleterious effects from moving it lower on the baffle by an inch or two?
Also is the woofer center 13" up from the bottom set in stone or are there no deleterious effects from moving it lower on the baffle by an inch or two?
Thank you John!
Thank you very much John Busch for your work and time on this OB design.
I "built" the Ultra version in a rough manner to see if I liked the sound of OB in general and your design specifically...I love it! It sounds better than the low budget models of Tannoy, B&W and Pioneer B22 speakers I have by some margin.
The coherence of the two drivers is spooky, especially considering the price of the drivers. How you came up with that pairing is amazing. No doubt a lot of time in on experimentation and iterations with drivers and crossover schemes.
The Ultras are very power hungry but when I listen to them at higher spl levels I very much enjoy them. The other speakers I have at same spl make me cringe and want to turn the volume way down. I also like how they load the room with sound and not the whole house.
For me, they do seem to be a little laid back on the higher frequencies. I have the Vifa padded with an eight ohm now going to try five ohm or so and see if that helps. Also I cheaped out and used an iron core inductor instead of an air type for the Vifa, so going to get an air core on it at some point.
As you can see from the photos I strayed off from the recipe quite a bit. The plywood was cut on 45 degrees from a renovation at work so I left it that way on one wing of the side panels. The other side panel is more or less at 5". The baffle needs bracing and lacks a base. The good is that the exaggerated wing creates an upright support for the baffle.
The crossover is just a rats nest with no real home yet. The Vifa was mounted in rubber from old rubber boots but the driver has tons of room to breath.
John has come up with a design that is very forgiving in its execution.
Again, thank you John (and Pano), for your time in on sharing this design. Both you guys have been very patient in this thread over for so many years.
John, just one thing, I plan to do a proper build and closer to your specs at some point, but may not if you are still planning to share a new OB with us. I would rather spend the time and money on your newest OB. I know you had mentioned that you had been short on time and had a health issue lately that prevented getting into a new speaker discussion. I hope your health has improved.
Thank you very much John Busch for your work and time on this OB design.
I "built" the Ultra version in a rough manner to see if I liked the sound of OB in general and your design specifically...I love it! It sounds better than the low budget models of Tannoy, B&W and Pioneer B22 speakers I have by some margin.
The coherence of the two drivers is spooky, especially considering the price of the drivers. How you came up with that pairing is amazing. No doubt a lot of time in on experimentation and iterations with drivers and crossover schemes.
The Ultras are very power hungry but when I listen to them at higher spl levels I very much enjoy them. The other speakers I have at same spl make me cringe and want to turn the volume way down. I also like how they load the room with sound and not the whole house.
For me, they do seem to be a little laid back on the higher frequencies. I have the Vifa padded with an eight ohm now going to try five ohm or so and see if that helps. Also I cheaped out and used an iron core inductor instead of an air type for the Vifa, so going to get an air core on it at some point.
As you can see from the photos I strayed off from the recipe quite a bit. The plywood was cut on 45 degrees from a renovation at work so I left it that way on one wing of the side panels. The other side panel is more or less at 5". The baffle needs bracing and lacks a base. The good is that the exaggerated wing creates an upright support for the baffle.
The crossover is just a rats nest with no real home yet. The Vifa was mounted in rubber from old rubber boots but the driver has tons of room to breath.
John has come up with a design that is very forgiving in its execution.
Again, thank you John (and Pano), for your time in on sharing this design. Both you guys have been very patient in this thread over for so many years.
John, just one thing, I plan to do a proper build and closer to your specs at some point, but may not if you are still planning to share a new OB with us. I would rather spend the time and money on your newest OB. I know you had mentioned that you had been short on time and had a health issue lately that prevented getting into a new speaker discussion. I hope your health has improved.
Attachments
Oblix - thanks for the photos and the details of your build. Yes, you can tweak the pad resistor to get the highs where they need to be for your room and speaker placement.
Have fun and maybe you'll like it enough to do a fancy build. FWIW, I had a pair made form scrap plywood from a construction site and they worked fine. Not pretty, but sounded as they should. I used them in my lava tube cave.
Have fun and maybe you'll like it enough to do a fancy build.
FWIW, I had a pair made form scrap plywood from a construction site and they worked fine. Not pretty, but sounded as they should. I used them in my lava tube cave.Because I built a 6' diameter baffle for the tweeter I believe that it may touch or go over the woofer cutout potentially. The woofers come in today so I'll find out for sure. I did draw lines at 15.125 which is what parts express says the outer diameter is and it was SUPER close. This is why I asked, I know there are guardrails but I was pretty sure that woofer and tweeter positions were the ones that were specifically ones to observe. If need be I can do a few things:
1. Position the tweeter a little bit to one side of the 5.5 inch cutout to give more clearance facing the woofer.
2. Shave the tweeter baffle down which carries risk as it will be done manually with a rotary tool i.e. I might jack it up and have to make new ones.
3. Lower the woofer by 1/2" to an inch from a center position of 13" from the bottom to more like 12.5" from the bottom. I'll know more for sure when I have the GRS woofers in hand.
THanks!
John
You used a boot as a baffle! That is the greatest, I love it!
John, I hope COVID didn't enter your household, I've been lucky enough to have not had it impact my family as of yet.