Thinking about giving OB a try--questions

Blooze · « **on:** 21 Oct 2010, 09:53 pm »

As the title says, I'm thinking of giving OB's a go. Will most likely be BIY route. Build it yourself as opposed to DIY; I'd like to go with a somewhat proven design as opposed to starting from scratch to begin with. I've listened to several pairs of Hawthorne Duets and was less than enamored--stuffy mids and dull high end. Of course that could have been because it was at an audio show and we all know how tough that can be for both exhibitor and auditioner. Fast forward to RMAF this year and I stepped into the Emerald Physics rooms. Holy C***!!!!! If they could get that sound at a show I can't imagine what a proper setup would sound like. My meager salary will probably never allow the purchase of one of those (well, maybe 5 years from now on a used pair they no longer make

), so I figure I'll try to make a pair of OB's. I'm not expecting to come anywhere close to EP's results obviously, but something of a taste of that spaciousness and smoothness combination.

I guess first off would be to see if my listening room would even work well. I've attached a few pics of it. It's a converted attic room for starters, so floor vibrations are there. Here's the dimensions. Floor is 19'6" x 12'. The counter area is 3' deep by 9'6" long. Ceiling height is 9' on the tall side, then angled down to about 7' on the ends and 6'6" on the counter wall side (matches the roof angles). The center part of the ceiling is flat.

My equipment stand is 2' x 4' and as of this moment my listening chair is 4' x 3' at 11' from my gear. As you can tell I don't have anything worth much yet as I'm just getting back into listening, mainly using old hand me downs, DIY, and stuff I've had for 25 years.

I'd like to keep the budget less than $700 for now. Maybe a tad more if including a Behringer.

wilsynet · « **Reply #1 on:** 21 Oct 2010, 10:59 pm »

Not at all answering the question, but it occurs to me that you could use some room treatments. At least at the first reflection points.

Also, have you considered bringing the speakers 3-4 feet into the room and a little further from the side walls? You may need to make corresponding adjustments to your listening position of course. I have found that this really opens up soundstage depth and 3-dimensionality for me.

I'm no room or acoustics expert, just my own experiences over the past couple of years.

Blooze · « **Reply #2 on:** 21 Oct 2010, 11:17 pm »

Yep about the room treatments. I haven't been in the room very long since renovating it (it was ugly checkered tile, murals and mirrors on the walls---ewwww). I've got fabric and whatnot to do it, just haven't yet.

If I move the speakers out 3-4 feet into the room I'll be sitting about 5 feet from them

They are about 8'6" apart right at the moment.Right now I've got my chair back about 3-4 feet from where it's at in the pic, leaving me enough room to get to my CD's and guitar equipment. The brown cabinet that's behind the chair is gone with the front of the chair moved back to where that cabinet was. It's about as far as I can take it back. I've moved those arrays about 100 times as well as my listening position and that's what seems to work best with them. They do sound better pulled out from the wall another foot or two, but the tradeoff is loss of bass. That, and it seems like they sound better almost shooting straight forward with very little toe-in. Crossing right in front of me the sweet spot is so small that if I move my head at all the sound is lousy. I'm hope my room is going to be long enough for OB's to perform well.

JohnR · « **Reply #3 on:** 21 Oct 2010, 11:44 pm »

I've found that in a room that size that the positioning from the rear wall does make a fair bit of difference to the measured response in the bass. I mean, OBs will work, I guess I'm just supporting wilsynet's comment about moving them way from the wall.

Blooze · « **Reply #4 on:** 22 Oct 2010, 12:06 am »

Quote from: JohnR on 21 Oct 2010, 11:44 pm

I've found that in a room that size that the positioning from the rear wall does make a fair bit of difference to the measured response in the bass. I mean, OBs will work, I guess I'm just supporting wilsynet's comment about moving them way from the wall.

I'll give it another try tomorrow and see. I don't have any problem with the way my speakers sound now, just wanted to give OBs a try. Something new I guess.

JohnR · « **Reply #5 on:** 22 Oct 2010, 12:10 am »

Hi, I meant positioning of an OB

I suppose it will have an effect with a box speaker, but I haven't measured it.

Blooze · « **Reply #6 on:** 22 Oct 2010, 12:44 am »

Quote from: JohnR on 22 Oct 2010, 12:10 am

Hi, I meant positioning of an OB I suppose it will have an effect with a box speaker, but I haven't measured it.

My misunderstanding

Any suggestions on designs?

JohnR · « **Reply #7 on:** 22 Oct 2010, 01:41 am »

Hm. Good question

Mine's in flux (like most here?) and has turned into a four way fully active. The B200 is popular, there's a thread just down the page discussing it with an alpha woofer and the neo3 gets discussed too I think. For a predesigned one there's one on mjk's site, will find the link later this avo.

canzld · « **Reply #8 on:** 22 Oct 2010, 01:56 am »

I was going to recommend the Visaton B200 based OB as well, having played with them myself for the last year. You can start with just the B200 full ranger, and add in bass (often eminence alpha 15) and treble (general opinion tilting to Neo3 dipole tweet) as taste or inclination strikes you. The B200 is not without issues as are all drivers, but these seem to vary with depend on amp and room. You certainly will not find a B200 based speaker to have stuffy mids and dull high end

. Total cost for the 3 sets of drivers just under 700.

My experience is that you will need to get your OB at least 4 feet off the front wall or you will not maximize bass output (although using an H-frame for your woofer can help shrink this distance) and may also have treble problems (enhanced), but you seem to have plenty of room to push your sofa back a few feet. I listen in close to a typical 8' triangle with the speakers.

studiotech · « **Reply #9 on:** 22 Oct 2010, 04:26 am »

Hate to sound like broken record here, but PLEASE PLEASE PLEASE put some treatments up. And none of that worthless acoustic foam either. If you wanna DIY something check around about making some nice 2' * 4' panels from rigid fiberglass or Bonded Logic acoustic cotton. It will transform the clarity of your system AND be worthwhile upgrade especially if you make some OBs.

You have a sweet little room and could really get some killer results since the side walls are so close. Also hit the ceiling at the point about half way btw you and the speakers.

Have fun.

Greg - tech - www.phatplanetstudios.com

Blooze · « **Reply #10 on:** 22 Oct 2010, 04:58 am »

Quote from: studiotech on 22 Oct 2010, 04:26 am

Hate to sound like broken record here, but PLEASE PLEASE PLEASE put some treatments up. And none of that worthless acoustic foam either. If you wanna DIY something check around about making some nice 2' * 4' panels from rigid fiberglass or Bonded Logic acoustic cotton. It will transform the clarity of your system AND be worthwhile upgrade especially if you make some OBs.

You have a sweet little room and could really get some killer results since the side walls are so close. Also hit the ceiling at the point about half way btw you and the speakers.

Have fun.

Greg - tech - www.phatplanetstudios.com

Thanks for the ceiling suggestion!!!

Yep, it's on the agenda for this winter. I've got the plans for some solidly built 2'x4' panels using the SAFB with the frame made of firring strips, just gotta build them. I think the ceiling is probably a part of the problem with all the angles.

Here's a pic of what they would look like.

So I was looking thru the forum some more and think this may be a good place to start?
http://www.audiocircle.com/index.php?topic=47314.msg429057#msg429057

JohnR · « **Reply #11 on:** 22 Oct 2010, 09:03 am »

Here's the MJK link:

http://www.quarter-wave.com/OBs/OB_Design.pdf

Here's another one using the Jordan JX92s:

http://www.quarter-wave.com/Project08/Project08.html

cujobob · « **Reply #12 on:** 22 Oct 2010, 10:43 am »

I'd stretch the budget and go for the GR-Research V2s. Danny was running a special on them...a few hundred over your budget, but I'd think probably worth it. OB7s or OB5s are also quite good, though not as dynamic.

I think the full-ranger route can be nice in smallish rooms, but the trade-offs generally aren't worth it to me. The Hawthorne OBs didn't wow me...I had a pair and briefly tested them out and wasn't sure they were worth a full build-out. Not terrible for the money and simplicity of the project, but nothing special IMHO.

Blooze · « **Reply #13 on:** 22 Oct 2010, 12:39 pm »

Thanks for the head's up. I listened to the V2's at LSAF last year and wasn't that impressed frankly. They sounded nice, don't get me wrong, but I couldn't see listening to anything but jazz-lite with them. Again, audio show setup issues apply. I much preferred John Busch's design using the Goldwood 18". They would play everything from the nuances of soft vocals, full orchestra, to room thumping metal (I know cuz I had him play some just to see

).

Maybe I need to make a trip and re-audition the V2's, though?

mcgsxr · « **Reply #14 on:** 22 Oct 2010, 02:47 pm »

OB is a fun adventure, and I usually advise that folks start small. There are a number of 4-8 inch drivers around that will give you a taste of OB, without sinking much time or dough into it. I would look around for that as an entry point.

Where are you? There might be some folks near you with OB's going that you could go hear, that might also help you get a feel for some of it, outside hotel rooms!

Rudolf · « **Reply #15 on:** 22 Oct 2010, 03:51 pm »

Quote from: Blooze on 22 Oct 2010, 04:58 am

Thanks for the ceiling suggestion!!!

Yep, it's on the agenda for this winter.

Before starting with any absorption on any wall, please please get a copy of Floyd Toole's "Sound Reproduction" and read chapters 3, 4 and 21. It is easier to get things wrong with attenuating first reflections than to do it right. Especially when dipoles give you the opportunity to avoid near side wall reflections to a high degree - without any special treatment.

Rudolf

studiotech · « **Reply #16 on:** 23 Oct 2010, 02:26 am »

Quote from: Blooze on 22 Oct 2010, 12:39 pm

Thanks for the head's up. I listened to the V2's at LSAF last year and wasn't that impressed frankly. They sounded nice, don't get me wrong, but I couldn't see listening to anything but jazz-lite with them. Again, audio show setup issues apply. I much preferred John Busch's design using the Goldwood 18". They would play everything from the nuances of soft vocals, full orchestra, to room thumping metal (I know cuz I had him play some just to see ).

Maybe I need to make a trip and re-audition the V2's, though?

I would agree here. Heard the V2s last year also. GREAT bass, good mids, "spitty" sounding highs IMHO. A little foam stuffed in the throat seems to tame it right down, so who knows.

http://techtalk.parts-express.com/showthread.php?t=220578&page=2

Greg

Blooze · « **Reply #17 on:** 23 Oct 2010, 03:26 am »

Spitty highs with the V2's. Yep.

I can't listen to Lowther's either. I've never heard one yet that I liked. It's like someone shouting in my face. And yes I've heard some that were supposed to be broken in and it didn't seem to matter. I've heard a couple that came close, but they were EQ'd to within an inch of their lives.

If you goto hifizine's site and look for LSAF 2010 coverage there's a little bit about John's "newest" creation on the cheap.

lonewolfny42 · « **Reply #18 on:** 23 Oct 2010, 05:31 am »

Blooze...

Quote

Yep, it's on the agenda for this winter. I've got the plans for some solidly built 2'x4' panels using the SAFB with the frame made of firring strips, just gotta build them. I think the ceiling is probably a part of the problem with all the angles.

Good thread by PeteG.....Link...

el`Ol · « **Reply #19 on:** 25 Oct 2010, 02:17 pm »

This is a bit more than you wanted to pay, but you would need no EQ.
http://www.lautsprechershop.de/hifi/dipass.htm