|26th October 2009, 04:53 PM||#1|
Join Date: Jan 2007
OB: Dark Star Shootout - Betsy vs. B200
After hearing the field-coil Lowthers and Feastrexes at RMAF, I wanted to build some kind of simple OB. I had a pair of Visaton B200's in the closet, and decided to build a certain variant of the legendary "Dark Star" OB found here:
Wild Burro Audio Labs - Fullrange Speaker Projects - Basic Open Baffle Design
6moons audio reviews: RoadTour Exit 5 with Michael Lavorgna
I decided to do a shoot-out of the B200's vs. the Betsys, so I ordered a pair which came in just three days. The Betsy is an economical $100 whereas the B200's are about $270 per pair, so any comparison is really about bang for the buck.
On this thread, I want to (1) give details on the build and the drivers, (2) give listening impressions of each, (3) exchange information with others who may have insight into this interesting and simple design.
The Betsy has economy construction compared to the over-engineered cast-aluminum frame B200. The Betsy's magnet is a lot smaller than the B200, but the Q is supposed to be about the same. The Betsy's have a higher Fs than the B200's. But the price difference is enormous.
The Betsy's remind me of the Pioneer BOFU20 -- best bang for the buck for projects on tighter budgets. The Betsy takes a slightly smaller hole than the B200, by the way. So the way to test is to try Betsy's first, then enlarge the hole and try the B200's (or build a removable mount).
I followed the instructions at the first link above. I decided to go all-out and used expensive 48" piano hinges (so-called continuous hinge available at hardware stores). These cost as much as the Betsy's! In retrospect, I don't recommend piano hinges because:
(a) they are expensive
(b) they overlap the hole, but it worked out okay
(c) there are many, many screws (hundreds)
(d) the hinges still have little gaps so you have to seal them anyway
The piano hinges do give a nice furniture look if you care about that.
I had the lumber yard cut up one sheet of 4'x8' and had scraps left over to make 48" x 1" strips for possible bracing (gluing the strip's grain at 90 degrees to the ply's grain, like an I-beam). But I haven't needed the bracing yet.
I attached the Betsy's with wood screws and installed t-nuts for the (eventual mounting of the) B200 because the B200 is really heavy and the Betsy is lighter. For the B200, I put a single hole at the 12:00 position, but that meant that 4 holes were overlapped by the hinge, so I had to recess the t-nuts into the ply. (Had I rotated the B200 by 30 degrees, only two t-nuts would have been overlapped by the hinge.)
I put a layer of rope-caulk under the Betsy. I usually use silicone, and torquing the screws gets the silicone to squeeze out. Not so with rope caulk, so I wonder if I used too much (it's visibile from the side of the driver).
Suggestion: the middle panel on this design is fine for the Betsy but a bit narrow for the heavier, wider B200.
Amp and Source
We set this up in the living room, not my listening room, so I just used a 2-watt Bottlehead, $39 CD player, $10 interconnects and lamp cord. Ultimately, this design will be hooked up to a laptop / digital EQ / outboard DAC.
Room and Position
Room is 19x14, and they are 4 feet from the wall. I liked the sound with the big wing extended completely, no toe-in.
I sat in a computer chair (on wheels) and rolled around to find the best bass in the room. This design is very sensitive to where you sit, bass-wise.
Bass: An 80Hz test tone is loud, a 63Hz test tone is louder still (due to Fs), and a 50Hz test tone is audible but way down. With digital EQ, I am guessing that 50Hz tone could be made louder but x-max would limit the overall sound level.
Wow. Absolutely beautiful music, depending on the material. Even without break-in, they surpassed my expectations by a mile. Clear, airy, and (on the right material) effortless. They sing.
Bass is clear and pretty low, although not meaty. It's tuneful, not viceral. If you like acoustic and small ensembles, I think you will absolutely love this design.
They sound best on music that is less dense, e.g. acoustic, voice. Lots of harmonics and dynamics stress them out. Heavy bass is out, but they surprised us with how low they go, when you are sitting in the perfect spot.
There's not so much room ambience, due (I think) to the massive size of the extended baffle, which probably ends up re-reflecting (and delaying) a lot of the backward energy. It made many of my old favorites sound new and interesting.
At RMAF, I heard a couple dozen expensive speakers that did not have the simple, special musical quality of this design.
Absolutely top-notch: Bill Evans, Diana Krall, anything acoustic, small ensembles, guitar and voice.
Excellent: early Miles Davis, Steely Dan, Donald Fagen (a bit bass-shy).
Interesting: Jethro Tull - voice and acoustic instruments sound beautiful, but when the band comes in (e.g. "Thick as a Brick") it sounded compressed. Some of that is due to the amp, though.
Not (Yet) Good: Pablo Casals' solo cello lacked richness and meat, but I think break-in will improve this greatly.
Nit-pik: On most songs, the bass was really clear, but on some songs, depending on the key perhaps, the bass wasn't tight and I think it was due to the song hitting around the driver's Fs, as the 63Hz tone did.
This system is fantastic and affordable! It reminds me of the BiB -- lots of music for a small price and easy build.
So many mega-buck speakers at RMAF failed to impress, but this simple build really delivers a lot of music. No speaker is perfect, but this design has a beautiful musical quality that, like the Bib, you have to hear to believe. Like other fullrangers, it's not going to do a convincing tympani like an Altec VOTT, but it has many positive (and some compelling) qualities of its own.
I will continue breaking in the Betsy's, and then give the B200's a go.
A big thanks to my wife, who helped me build and audition them, and to the Santa Fe Audio Society, especially Monte Verde, Serenechaos and Feastrex OB mad scientist Phil Townsend. Thank you to pjanda1 (Betsy maker), and thanks to the generous gurus here, GM, MJK, Scottmoose, Dave Dlugos and too many others to list.
Last edited by rjbond3rd; 26th October 2009 at 04:56 PM. Reason: grammar
|26th October 2009, 05:58 PM||#3|
Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Blog Entries: 5
I look forward to the rest of your journey. Pictures?
In another thread i said you were going to have to splurge to hit $200. Guess that was the piano hinge.
|27th October 2009, 05:12 AM||#6|
Join Date: Jan 2007
The drivers are breaking in really fast (wife thrashed them all day). Yesterday, when I walked into the other room, the speakers were very bass-shy, but now, listening from the other room, they have much more bass.
1. Dire Straits - Communique: wow, almost perfection, Knopler's strat sounds clear as a bell, bass and kick drum are fat and full (although it's still not, and never will be, visceral).
2. Solo cello - beefy! Casals was vastly improved, and Janos Starker's cello was rich and full of harmonics and scraping sounds, sounded life-sized (lots of breathing and thumping on that recording).
3. Jethro Tull - "Aqualung" and "Thick as a Brick" are starting to sound good at the dynamic parts. Electric guitar sounds great. Who knew that guy made so many weird talking-noises when he plays the flute? (And what the heck are those songs about?)
4. Donald Fagen, Kamakiriad and Morph the Cat: bass and kick are ample, no complaints.
5. Jane Monheit, Live at the Rainbow Room: Ron Carter's bass is very clear, with each note distinct, but light in weight. Still, the notes are there and that wasn't the case yesterday.
All this is without any digital EQ. Eventually, with more break-in and some EQ, I think everything could be ironed out (as much as possible with a single fullranger).
Two tricky bits:
* It takes time to find the listening spot where (a) bass is best and (b) the stereo image is perfect. Lots of little tweaking is required.
* The speakers are mounted low, so sitting in a computer chair is way too high for this design. Sitting high makes the players sound small, but this is easily corrected by listening more on axis (i.e. sitting on the couch).
Dave, I will try to take pix (I don't own a camera at the moment) and yes, the hinges were a regrettable budget-killer. Serenechaos, pizza awaits you! Human.bin, I will keep Casals at the forefront. Godzilla, I know you will appreciate these drivers and this design.
|27th October 2009, 07:49 PM||#7|
Join Date: Nov 2005
Location: New York
>>> Who knew that guy made so many weird talking-noises when he plays the flute?
LOL! One of the drawbacks of many of the speakers we build is that our quest for the best returns our efforts with everything on the recording... including the parts we'd rather not hear. I wonder if you will hear even more of this with the B200? One can argue you're getting closer to the performers and their performance... no argument there... but it could be distracting. I cracked up when i read your comment btw. Thanks for the cheerful laugh! I needed one today.
PS, i am listening to a pair of KLH i found in the trash. These speakers are probably 30 years old and sound pretty bad BUT playing in the background they sound pleasant enough and provide atmosphere in my quiet office.
Never will i be able to hear the "weird talking-noises" or grunts from jazz keyboardists thru these old KLH... but i consider that a good thing while trying to concentrate at work. Listening in my home thru my BIBs i want to be transported to the venue where every little detail is much more welcome and adds to the experience. Good to know the Betsy's will get me there too. Thanks again for your listening impressions.
Last edited by Godzilla; 27th October 2009 at 07:50 PM. Reason: url bad
|27th October 2009, 08:04 PM||#8|
Join Date: Aug 2002
Location: victoria BC
OT for a minute -this somehow reminds me of a very interesting, "slightly(?) dark" film I caught a few weeks back - "The Jacket" with Adrian Brodie, Kiera Knightly and Kris Kristofferson.
retired from posting - it's been a blast
|27th October 2009, 10:03 PM||#9|
Join Date: Feb 2004
Location: los alamos
Pizza is good!
Jarrett is better!!
Do you have the Köln concert?
If not i'll bring a copy; we used it as one of the references @ rmaf this year.
I like solo jazz piano; for relaxed listening as much as for critical listening, and that has become one of Deb's favorite CDs.
|28th October 2009, 01:17 PM||#10|
Join Date: Jan 2007
Godzilla, you are the luckiest guy on earth, just /finding/ stuff like that. Chris, now I'm more curious than ever about "Thick as a Brick." Serenechaos, I don't have that album but when you see my CD player, you might have second thoughts (it's junk and the door sometimes has to be pried open). I'll have to get something better for the listen.
More to report:
1. I think the Betsy's break in really fast, and are mostly there. Bass is great! Overall, they are now excellent on about 90% of the material that I like, and only have a touch of something in the upper midrange on e.g., lush Steely Dan harmonies, but that's life with a fullrange sometimes.
2. Janos Starker's solo cello is the best thing yet. Captivating. Haunting. Really there in the room. There is gobs of bass for music like this. On the very lowest notes, I thought the baffle was resonating (or was it the cello, or a slight room mode from the space he was in? It was just on one note, so too quick to tell from the couch The realism is incredible to me.
3. One reason why the baffle doesn't resonate more could be the over-abundance of rope caulk.
4. This design might work so well because the room is a concrete slab with a thin carpet, and the front wall (the wall you face) is mostly a big brick fireplace.
5. Any limited dynamics could be blamed on the little 2-watt Bottlehead but I never go above noon with its volume. Still, that's practically no headroom. The Betsy's are decently efficient (specs say 92.4 db).
5. My life now consists of waking up early to hear the Betsys, rushing to work, rushing back for a 20-minute listening session at lunch, then back to work, then long listening into the night with the lady of the house. All my records are new again. Oh, and the best thing: I haven't watched any television since the Betsy's started making music. No more having CNN on in the background -- that TV may end up in the garage.
This weekend, we're varnishing them, and then it's time to try the B200's.
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