Building a new OB

Tr3vWh0r3 · « **Reply #200 on:** 21 Mar 2007, 02:12 am »

Okay Bob, here's how the room should look when you're done.

Bob in St. Louis · « **Reply #201 on:** 21 Mar 2007, 08:04 pm »

Thanks dude! You even got 'em on the big screen, that's cool.

Bob

Bob in St. Louis · « **Reply #202 on:** 27 Mar 2007, 03:01 pm »

The result of a few hours spent this weekend:

mcgsxr · « **Reply #203 on:** 27 Mar 2007, 08:00 pm »

Um, can I ask a question about design?

I see that the driver is held with magnet mount, I assume that is to reduce baffle vibration - but the magnet mount post is connected to the same bottom piece as the actual baffle is.

No vibration issues I assume?

I like that speckled paint finish, it looks good.

All the best,

Bob in St. Louis · « **Reply #204 on:** 27 Mar 2007, 08:46 pm »

No vibration issues Mark, well...ok...very very little vibration issues. Very slight, barely felt at all.
My original idea was to make that rear leg self supporting and have the front section (baffle section) be 'self standing'. Due to the shape of the rear leg, angle of the leg, weight and mounting position of the driver, I ended up having to make the unit one piece.

My wee little brain is working on a "Gen II" baffle design that will have NO contact. A true two piece design. If I can design a driver mount that can sit safely on the floor of the HT room, while I'm build a "front half"/baffle structure in the workshop, this would perform a few functions:

#1, The obvious; no vibration transmitted to the baffle.

#2, The baffle design could be redesigned without having to make another driver support. Kind of like a modular design. Baffle designs and shapes could be switched and compared in litterally seconds.

#3 The driver is being constantly handled, removed, reinstalled since I build these baffles on the weekends. So I have to make sure that I have them ready to use for the week regardless of what state of build they're in. One of these days, I'm going to "F" one of them up because they're "in the construction zone".

#4 If I have the driver safely mounted on "it's perch" in my room, I can be making a new baffle in the workshop. No more touching the driver. I can build it and implement it whenever I want.

#5 Last but definitely not least, my biggest problem with building them this way is that since I'll do a little construction, then implement them into the system, my ears are gradually getting used to the sound. So when I'm finished, I'm not sure I've improved anything since "the new sound" has been creeping up on me for that past few weeks (or months

in this case.)

The new design would allow me to completely build one and implement it, for instant confirmation of wether or not it sounds better.

I like the sound these are creating, but in the end was it worth the effort?
Did I IMPROVE the sound?

Bob

gooberdude · « **Reply #205 on:** 2 Apr 2007, 03:40 pm »

hey guys,

i want to pull the trigger & buy a pair of OB drivers...my 1st foray into this. On Saturday i had a chance to audition the Ronins from Nomad Audio, i really like the OB sound. Paul Hilgemann has a winner with that design. Since I want to spend 10x less than the Ronins cost (initially) i'm fishing for driver recomendations.

At this point I'm interested in 3 difft drivers: B200, Hawthorne Silver Iris & the new Hemp Acoustics 8" for OB. If Hawthorne has their 10" co-ax out this would be a 4th choice....

As a newbie, would one of these be easier to implement successfully? Having no x-over interests me, but i like the sound my updated Thiel CS2's put out, so dynamics are important.

I do augment the bass with a pair of powered 12" subs & my room is good sized & acoustically treated. Dealing with the rear wave should be easy, my speaks sit about 6' from the rea wall - out into the room.

Bob in Stl, the frames for your Iris' look awesome!!!

JohninCR · « **Reply #206 on:** 2 Apr 2007, 03:52 pm »

Dude,

Without a doubt the 15" is the easiest to implement. Since you have the bottom end handled, virtually any baffle will work. The reason it's easier is due to the smooth response, the coax setup reduces rear wave HF, and the large cone has a wider range of surface area making baffle shape and dimensions less critical.

gooberdude · « **Reply #207 on:** 2 Apr 2007, 04:01 pm »

Thanks John! I'd definitely leaning towards the SI drivers.

having no x-over definitely makes me curious, but I like the sound large drivers produce.

this week will be spent going over posts here and at other forums.

matt

mcgsxr · « **Reply #208 on:** 2 Apr 2007, 05:04 pm »

No secret I am very happy with my b200 Visatons, but honestly, were I starting out fresh, I am sure I would put a set of those Iris through their paces, just to see what the fuss is about. I hear very good things about them, from folks I have respect for.

As for subs, yes, I would always recommend some sort. OB or otherwise, they make life better!

JohninCR · « **Reply #209 on:** 2 Apr 2007, 05:19 pm »

Mark,

I'm finally getting magic out of my B200's. I listened to them full range in my dipole waveguides for 3 days with no augmentation, just a little boost from a high Q rumble filter at the very bottom and something like the BSC filter you guys are using. I'll have to eat some serious crow when I post the full documentation. I still haven't figured out exactly why I'm getting good bass. I tried very big flat baffles with them and never got anything like this. You may want to wait before building something new, these are that good. Plus the other things I was shooting for with the design fell into place too, so I may actually be at the end of the journey.

mcgsxr · « **Reply #210 on:** 2 Apr 2007, 05:44 pm »

Glad to keep waiting, just penning ideas at this point - trying different shapes, in the hope of finding a pleasing aesthetic!

Always glad to see what you come up with!

corloc · « **Reply #211 on:** 2 Apr 2007, 06:00 pm »

Quote from: JohninCR on 2 Apr 2007, 05:19 pm

Mark,

.....I'll have to eat some serious crow when I post the full documentation. .... Plus the other things I was shooting for with the design fell into place too, so I may actually be at the end of the journey.

As far as I'm concerned John. If you tell us how you did it, you don't have to eat crow at all. aa
I haven't had much luck with baffles in my smaller room.

DanTheMan · « **Reply #212 on:** 2 Apr 2007, 07:33 pm »

Great news John! You should post your results when they are completed. I knew as soon as I read the idea that there was great stuff in there. I didn't expect bass, but suprises are always the best gifts.

You're definitely on to something too Bob. Why didn't I think of that! An easily modified/changed baffle with a permanent, unattached magnet mount. Especially now that you are getting experience with different manufacturing materials.

Good to hear it.
Anxiously awaiting,

Dan

JohninCR · « **Reply #213 on:** 2 Apr 2007, 07:39 pm »

Corloc,

The eating crow part is regarding real bass without an augmenter. I said a number of times that it wasn't possible except for a narrow selection of music. Though I'll end up crossing to augmenters so I can crank it to concert levels when I want, what I'm hearing really caught me by surprise and I've even been throwing Pink Floyd and reggae at them. I turned them on for an evaluation listen just stacked up on some small boxes, and have been hesitant to touch them and mess something up.

All I was shooting for with the design was controlled polar response with increased directivity and reduced response outside of the waveguide's reach. I got more than expected in that regard with response dropping sharply as you get outside of the plane of the waveguide panels and greatly reduced at the sides at all frequencies. Within the soundfield response is quite balanced, so beaming is cured. I can move around anywhere in front of the speakers and tonality and spl remain well balanced. Nothing else I've built has come close. I even seem to be getting an increase in sensitivity. Plus the thing the B200 excels at already, outstanding vocals, are enhanced with even more presense. I believe this similar to their fronthorn cousins, but without the inherent beaming of traditional horns.

If I was reading this post from someone else, it would sound like a bunch of too-good-to-be-true fooey to me, so I'll try to stay somewhat guarded until I have plenty of measurements. While the bass surprise may turn out to be a unique product of my room and placement, the other benefits are quite real and I only dared to hope for some of them when I started the project. The one thing I'm not happy with is size. They're 22" high and wide, and I can only shave 2-3" if I go with a smaller driver. We'll see how the Fostex F120A's and FE108's fare in a smaller version.

Bob in St. Louis · « **Reply #214 on:** 2 Apr 2007, 08:04 pm »

Gooberdude - I have a feeling you know what driver I'd vote for! aa
"They" are soon to be releasing the 10" Coaxial, and the Sterling (upgraded) version of the 15" is 'in the works'.

Dan - Don't worry that you didn't think about it first. After all, you're the one that suggested I get the Sterling 15's as the new front mains and set the current 15's as the rear surrounds instead of buying the 10's for the rears. There! We're even!

mcgsxr - I've tried to create as much fuss about "these drivers" as I can. My search is over. They make my nipples hard.

John - Crow tastes like chicken. (I know, I've tried it). I'm very curious to hear your numbers when you get them.

Bob

JohninCR · « **Reply #215 on:** 2 Apr 2007, 08:14 pm »

Quote from: Bob in St. Louis on 2 Apr 2007, 08:04 pm

I'm very curious to hear your numbers when you get them.

Hopefully one will look like a straight line and the other a perfect figure 8 at all frequencies.

mcgsxr · « **Reply #216 on:** 2 Apr 2007, 08:15 pm »

Quote

mcgsxr - I've tried to create as much fuss about "these drivers" as I can. My search is over. They make my nipples hard.

Bob, you kill me, I will have to explain to my office mates, why I just cackled out loud!

gooberdude · « **Reply #217 on:** 2 Apr 2007, 08:20 pm »

I just ordered a pair of the SI's...couldn't wait...way too curious.

No clue about my 1st attempt at a baffle, but i'd like to keep it real simple initially since i'll be moving in a few months.

mcgsxr · « **Reply #218 on:** 2 Apr 2007, 08:29 pm »

God forbid I send you over to another forum (!) but the Hawthorne forum has some excellent threads about designs - I see lots of guys using baffles barely bigger than the darn 15!

Just promise you will post some pics, and impressions here!

http://www.hawthorneaudio.com/forum/viewforum.php?f=2

gooberdude · « **Reply #219 on:** 2 Apr 2007, 08:46 pm »

I will for sure....

I frequent a few other forums but definitely feel like AC has them ALL beat, hands down, in terms of great advice from good people.