[drphoto]

Well, I'm not nearly as competent as guys like Ed and Tom, but here's one of my partially completed H-frames. I had a flat pack, but it was inaccurate (the main baffle needed trimming) and much of the internal bracing was missing.

I wanted to find someone w/ a table saw, but finally just took a hand held circular saw to it. I figure I could make up for somewhat sloppy cuts w/ glue, shims and a liberal application of bondo. I don't even think the thing is perfectly square, but it doesn't matter. I added the outer skin of 1/2" MDF thinking more mass couldn't hurt and it would let me do a nice round over.

I plan to seal 'em w/ polyester resin (even considered some glass cloth, but probably overkill) Final finish will be a truck bed liner spray.

My point to posting this, is anyone can build these even if you a semiskilled, tool lacking dope like me. 

[ebag4]

Hey Joe (that could be a song!), I don't see anything wrong with those at all, in fact they look quite solid, good job  .

Best,
Ed

[TomS]

Lookin' good! And plenty stout too 

[drphoto]

Thanks guys. I don't have Ed's patience. I had these up and running almost before the glue was dry. Stout? yeah, they're starting to approach 'hernia' weight.

 Thanks to GR and Rythmik, you can build a killer bass setup on the relative cheap. If I can do it.....anyone can. OB/servo bass is something everyone needs to experience.

To paraphrase that character from Happy Gilmour "You can do it!"

[Hank]

Way to go!  It's good to see someone with no experience and not many tools be self-confident enough to jump in and give it his best shot.    As my old poker buddy, Willy Shakespeare wrote: 
"Our doubts are traitors,
And make us lose the good we oft might win
By fearing to attempt."
You are to be congratulated on your results.

[drphoto]

Well, as someone who started my own business in my 20's and now putting that aside to apply to pharmacy school at age 50, I suppose I'm not very risk adverse! Or, I'm just crazy, which probably closer to the truth. 

[rklein]

Hey Joe:

Nice job on your OB H-Frames!  Tables saws are wonderful to have, however, as you have found out much can be accomplished without one.   I have built enclosed bookshelves with doors, pantries, complete enclosure for a tube/sink in the utility room, beautiful countertops, etc. with nothing more than a circular saw and metal guides.

I am also building some speakers that I will be showing pics of soon.  Just finished veneering them in rosewood today and routering out the driver holes.

Again, congrats on a job well done.

Randy

[drphoto]

I found I wasn't diggin' the sound w/ 2 H-frames as much as I thought. No real low end, and if I simply turned up the level, the drivers would start to distort.

 So last night I pulled the drivers out of the one not pictured and put them back in my BABBs which 3x3x1.5" flat panels. Much better. So now one H-frame and 2 big flat baffles.

Doesn't make sense. The H-frame should make them more efficient and improve punch and low end output.  I've got the drivers in the H-frame wired so they are out of phase, (driver coil and servo) which I believe is the correct way to rig them.

 I have a very unusual room. The rig is in a balcony that is 20x25x8 which overlooks the main room which is 20x60x20. (yep, 20' ceiling)

[ebag4]

Hi Joe,
Just a note, when you use the H Frame the drivers are reversed from each other as opposed to the way they are oriented on a flat panel.  This means that (in this case) the first woofer off of the amp needs to be wired in reverse polarity (red to black, black to red) and the second woofer is wired in normal polarity.  If you don't do this the woofers will play 180 degrees out from each other negating most of the bass output (I know because I did it).  When you get them wired correctly a great big smile will be permanently attached to your face.  This may not be your issue but it certainly sounds similar to my experience.

Best,
Ed

[Danny Richie]

Doesn't make sense. The H-frame should make them more efficient and improve punch and low end output.

Yep.

I wired the coils wrong once and had the amp driving the sensing coils and the driver coils were being used as sensing coils. Output was quite limited. I'd double check the wiring.

[ebag4]

I've got the drivers in the H-frame wired so they are out of phase, (driver coil and servo) which I believe is the correct way to rig them.

Sorry Joe, I didn't see this when I first posted.  BTW, the driver coils are wired series parallel and out of phase and the servo coils are wired in series.

Best,
Ed

[Danny Richie]

Driver coils are in parallel and sensing coils are in series.

[Danny Richie]

See this diagram:

http://www.gr-research.com/pdf/V-1%20OB%20woofer%20wiring.pdf

[drphoto]

Problem solved! Yep, it was the wiring. I had the servo's paralled too.

Thanks for the diagram. I would have never figured it out on my own.

Oh, one other thing. Now that I've got 2 amps. Does it make any difference which input (L/R) to use? I mean, they're mono amps....right? Any diff between using low vs. hi level in? I think I read some theory that running a hi level in off the main speakers makes for better integration, but not sure why that makes any sense.

I'll put the drivers back in the other box now and give it a spin. Then I've gotta force myself to take 'em apart and get a proper finish applied.

[Danny Richie]

Does it make any difference which input (L/R) to use? I mean, they're mono amps....right?

You can get a better sound via the RCA input (low level) typically, but with a really high quality amp it can sound just as good through the speaker level inputs (high level).

[zybar]

Yep.

I wired the coils wrong once and had the amp driving the sensing coils and the driver coils were being used as sensing coils. Output was quite limited. I'd double check the wiring.

Been there and done that.   

George

[drphoto]

Put the drivers back in the second H-frame. Now we're cookin' w/ jet fuel!

Amazing how electronic devices work so much better when they're wired correctly! 

[ebag4]

Put the drivers back in the second H-frame. Now we're cookin' w/ jet fuel!

Amazing how electronic devices work so much better when they're wired correctly! 

 

I mis-wired mine the first time as well and I had Danny' drawing .

Best,
Ed