[greg7]

Hi. I'm new to this and needing advice. I'm considering building an OB speaker. I want something tube friendly (I own a 30 wpc push-pull integrated) and as minimalist as possible, preferably no crossover. I don't know if that's possible, though, so no big deal there. Up to $2000 what would my best option be for sound quality with those criteria? I'm considering Hawthorne Audio (though they use a crossover), Monacore B200, PHY-HP H21LB15, even the small CSS full-range driver.

[D OB G]

I'm just about to use the PHY-HP driver (SAG) as a midrange, but with a tweeter, which I feel will be mandatory, as the response drops like a stone at 10kHz.

Many people will recommend the Visaton B200 (which I haven't heard).

I didn't have any success with the Fostex FE206e I tried (I consider it the worst driver I have ever heard!).

David

 

[D OB G]

(yes, I used the Fostex with bass augmentation!)

David

[Bemopti123]

It seems as if Fertin with his special field coil drivers have allowed his daughter to come out with her own designs.  She has the option of pushing the drivers with a Field coil circuit OR Alnico magnet.  The Field coil drivers will set you back $2200 a pair + power supply.  The Alnico designs are 1/2 of that...12" diameter with hi qts and efficiency.  They have an add in Gon with the specs and some shots.

Had I known about this happening, I would have invested on a pair of $2200 fieldcoils.  The Supravoxes are Way too expensive. 

[stereogeek]

Here's a shameless plug for the Hawthorne Audio Silver Iris's.Great OB sound for $300! And customer service second to none!!! I,m very happy with mine(can you tell?).

Steve

[JLM]

greg7,

Unless you like dinking around and making sawdust, cabinet design should be left to the professionals, even though their primary effect is limited to 300 Hz and below.  Its obvious to me that quality sound requires quality drivers, especially with single driver designs (there is no place for a poor driver to hide). 

The Hawthorne Silver Iris is nice, easy, and inexpensive but is a coaxial driver, which IMO is not a single driver.  Dipoles offer a difused presentation and really need room behind.  The Silver Iris has incredible deep/full bass for a dipole, plenty for all but the fanatic bass hounds.  These drivers are very well built and plenty efficient for your amp.  They provide a very "easy to listen to" kind of sound.

You should check out Bob Brines: http://www.geocities.com/rbrines1/

Bob is a good guy (so is Darrel and Dave from Hawthorne as I've met/know all three).  He has good woodworking skills and really knows his way around Martin King's MathCad application for speaker design.  His prices are more than fair.  He'll sell plans, pre-cut panelized cabinet kits, pre-assembled cabinets, or fully completed speakers.  My FTA-2000 is a couple of steps better than the Silver Iris  in terms of bass depth, level of detail, imaging, tone with a more traditional type of presentation.  Bob's site mentions his like of the Baroque, but Led Zeplin never sounded better.

Most don't know about transmission line (TL) cabinet design and so are "afraid" of them (emotions closing the mind to other possibilities).  TL's provide deep, fast, musical bass that can only be matched/exceeded by very large concrete bass horns.  Construction-wise they are no harder to build than a sealed cabinet that has a brace.  TL design simply shapes the interior of the cabinet so that backwave energy is directed away and properly tuned for optimal performance.  Bass impedance "hump" is reduced, response extended with a roll off that complements room reinforcement gain.  Mid-range is "cleaned-up" as backwaves don't reflect back through the acoustical semi-transparent driver cone material.  For years the big hold-up with TL has been lack of design tools, but thanks to Martin King and others, that day is behind us.

IMO the Fostex F200A and Lowther 8 inch drivers represent a good compromise between cost and quality of extended range drivers.  And TL's are the only way for them to deliver full range sound.  If you want lots of deep bass or have a very large room, the smaller versions of these drivers could be considered with use of a good subwoofer (or two).

OTOH, if you want quality and really cheap/easy, try "the mighty" F200A in an open baffle.  You'll lose some bass output and have a dipole presentation, but all you'd be out is a sheet of plywood.  It a season to taste kind of thing.

[tubesguy2]

Greg -

If you just want to see if you can live with OB, with it's room and setup requirements, and see if you like the OB "sound" I'd recommend something like the Ciare CH250 and a couple of sheets of plywood.  I definitely wouldn't recommend just jumping in with a $2000  expenditure right off the bat.  - Pat

[Alan]

Well, I was expecting one of the guys who built these to chip in, but here's the big thread.

http://www.audiocircle.com/index.php?topic=19253.0

[tubesguy2]

Well, I was expecting one of the guys who built these to chip in, but here's the big thread.

http://www.audiocircle.com/index.php?topic=19253.0

Thought I'd spare him the tortured and overwrought prose.  - Pat

[mcgsxr]

I would recommend the Darkstar thread, it is a great read, and offers some good insight into a variety of areas for learning about OB.

I use the b200, but I am having a hard time recommending it straight up as a first toe in the OB water.  I think it an excellent driver, and it will amaze you in the right baffle, in the right room, with the right ancillary gear - but, miss on that combo, and you could have the other experience I have had with these drivers - weak bass, and very treble centric sound.

The FR125's from CSS would also be a good intro.  Easier to get right, but not as good (in my experience) as the b200 when done right.

I can recommend something really odd as a first step - a set of car audio 5.25 or 6x9's.  Meant for OB, and will give you a taste of the sound that you can find, with some effort, on your own.

I know they are coax, and that might kill it for you, but for $15 on eBay, it might set a good direction for you to invest far more in, in the future.

The Silver Iris are reputed to be great (I have never heard them) and there are Fostex that can be experimented with on the cheap too.

I recommend playing with some cheap drivers, on cheaply built OB as a first step - if you like the basics of what you hear, then you will want to go further.  If the fundamentals fail to entrance you, you might save some time and $$ and look elsewhere for the best speaker for you.

Have you heard any non OB single driver speakers?  JLM recommends the TL Bob Brines stuff (never heard those either, but they have a solid following) but you could consider the Horn Shoppe Horns, Louis's creations (Omega), or some other recommendations to be found in this circle - http://www.audiocircle.com/index.php?board=128.0.

I am not trading my b200 based OB for anything, anytime soon (nearly 3 years now) but it can be daunting to get into, and in my estimation they are far better with a helper woofer.

[Dmason]

I second the car speakers experiment... the Focal Car speakers are REALLY good on OB with buckets of bass, and can always be found on eBay.

In South America, I had cheapie Kenwood singles with whizzer cones, powered by a Clari-T amp, on plywood baffles shoved into the corners, and it was really very, very good. Car speakers will allow you to decide if the no box vibe is for you before you get any further involved.

I will say that single drivers for mid/treble with bass enhancement is pretty hard to beat. Horns, pipes, and lines kill most box type speakers outright.

Martin King's latest paper which includes a highly cost effective plan for two way OB would make a great follow on, to more full range ~50Hz sound. www.quarter-wave.com

[Brad]

Not sure what scale you are looking at.

I love my Hawthornes in OB  , but they are definitely not single-driver (they are coax, so present a point source)
I had and liked a pair of B200s in OB, but for my tastes they needed a lot of bass help and were pretty tweaky.

The FR125's that Mark mentions would make a good first project
I noticed some of the smaller Tang-band drivers that had some specs that MIGHT work in OB in near-mid range

I did just put a pair of Polk DB690's in my truck.  I bet they would sound pretty good in OB, but again, not single driver.

Are you going to supplement with a sub or woofer?
Is this just to get your toes wet with OB?

To me, OB has a realism to it not quite found with boxes.
It's cheap to experiment with, and for not a lot of work, can provide excellent results.