Open Baffle Epiphany!

hnash, which of the FR drivers in the 8"-10" range tend to work best, unadulterated and in OB configuration, from your experience? I'm aware of the Fostex, Betsy, and AudioNirvana drivers. I've seen posters discuss large vintage models and Lowthers, but the Lowthers sound pricey and the vintage speakers seem to require expertise I don't have at this point, as far as locating them, understanding different models, etc.

Thanks much for your input as well.


hnash53 said:
You are off to a good start with your concept. You can find out if "The Dark Side" is something that appeal's to you.
My only suggestion for choice of FR driver would be try to stay away from one's that need correction (notch filter's) to keep the complexity down.
Some of the FR's can shout.
The use of a sub to start will be cost effective.
Click to expand...
I can vouch for that "shout" that some full rangers can put out... and it can be tough to tame. Your comment is right on.[/QUOTE]
 
DavidTT said:
hnash, which of the FR drivers in the 8"-10" range tend to work best, unadulterated and in OB configuration, from your experience? I'm aware of the Fostex, Betsy, and AudioNirvana drivers. I've seen posters discuss large vintage models and Lowthers, but the Lowthers sound pricey and the vintage speakers seem to require expertise I don't have at this point, as far as locating them, understanding different models, etc.

Thanks much for your input as well.

I can vouch for that "shout" that some full rangers can put out... and it can be tough to tame. Your comment is right on.
Click to expand...
[/QUOTE]

The AudioNirvana Classic 8s I had for awhile before I got into OB. I mounted them in some large Pioneer cabinets and they are impressive. I have a quadraphonic receiver and the four large Pioneer cabs just didn't fit well in my space. So I ended up selling the Classic 8s along with the Pioneer cabs. But I have thought that if I ever wanted to try AN speakers again, I'd try the Classic 8s in the OBs I'm using now.

https://www.ebay.com/itm/1966-vinta...650976?hash=item213c2f42a0:g:B5oAAOSwLWZam1Hr

The link above (no affiliation) is for one of the Heppners that I use... (I think he's a bit overpriced for ONE speaker) I have four in my quad system now, with two extras in the closet. These are speakers from the 60s, often "harvested" from vintage electric organs. I was very impressed when I bought the first pair and I bought 4 more and have been running them in my OBs now for some time. The Heppners are very "sensitive" speakers... probably upwards of 95dB/1 meter/1 watt, and easily powered by nearly any receiver (my Sanyo quad is about 16 watts per channel... maybe 20 tops).

When I got them, I A/B'd them using a speaker switch I have and put them up against some Polk TSi200s I was using. Except for the bass/low end, the Heppners were all over the Polks... and I liked the Polks. After using the Heppners for about six months, I did an A/B test again... just to see if my brain/ears were fooling me. The difference was again huge... the Heppners all over the Polks. Now while those Polks are far from top of the line (which I can't/won't afford), the Heppners in OBs still sound super to me. I wrote about re-doing the A/B test a few months ago in this thread.

As mentioned recently in this thread, I augment the bass/low end with a subwoofer. Once in awhile though, I will turn off the sub, and put the "loudness" on with just the Heppners playing. It takes a moment to get past the reduction in bass, but after several minutes, I am enjoying the sound a lot.

I'm not trying to sell you on the Heppners.. just sharing my experience. Many pairs of ears hear differently. As I mentioned, I tried several different pairs of 8" speakers,... modern and vintage... and none were expensive.

If I were to start looking again at some full rangers, I'd look on eBay at 8" and 10" vintage speakers (4 or 8 ohm usually). There are 8 & 10 inch Wolverines which some people like. But there could be lots of unfamiliar names of speaker manufacturers you might run into... if inexpensive enough (I'd never ever heard of Heppner speakers before). Utah speakers are sought after, too.

https://www.ebay.com/itm/Heppner-6-...872358?hash=item3af49a8c66:g:P8AAAOSwThtZ5TEf
That's another Heppner... he's calling it a 6" speaker, but with that 24398-0, I'm pretty sure it's another 8 incher. The small tear in the cone can easily be repaired using some ordinary wood glue dabbed on front and back of the cone... I've done it with many speakers, and doesn't seem to affect performance.

I am by no means any "expert" on OBs in contrast to many others in this extensive thread.

I hope others will chime in here with their experience with the 8 and 10 inches full rangers. Maybe they won't be as "wordy" as I.
 
Thanks MUCH for your input hNash! I suppose I'm getting ahead of myself. I'll prep my test baffles this week, but if they sound good I see myself jumping right into the fire very soon, although as I noted earlier I'd love to arrive at a simple, single-driver OB with minimal bass assistance if possible. It's so difficult to avoid the rabbit hole in this hobby! I have been able to avoid most of the costliest aspects of it so far though, and one great thing about OB experimentation is that it can be done on the cheap. Gotta love that.




The AudioNirvana Classic 8s I had for awhile before I got into OB. I mounted them in some large Pioneer cabinets and they are impressive. I have a quadraphonic receiver and the four large Pioneer cabs just didn't fit well in my space. So I ended up selling the Classic 8s along with the Pioneer cabs. But I have thought that if I ever wanted to try AN speakers again, I'd try the Classic 8s in the OBs I'm using now.

https://www.ebay.com/itm/1966-vinta...650976?hash=item213c2f42a0:g:B5oAAOSwLWZam1Hr

The link above (no affiliation) is for one of the Heppners that I use... (I think he's a bit overpriced for ONE speaker) I have four in my quad system now, with two extras in the closet. These are speakers from the 60s, often "harvested" from vintage electric organs. I was very impressed when I bought the first pair and I bought 4 more and have been running them in my OBs now for some time. The Heppners are very "sensitive" speakers... probably upwards of 95dB/1 meter/1 watt, and easily powered by nearly any receiver (my Sanyo quad is about 16 watts per channel... maybe 20 tops).

When I got them, I A/B'd them using a speaker switch I have and put them up against some Polk TSi200s I was using. Except for the bass/low end, the Heppners were all over the Polks... and I liked the Polks. After using the Heppners for about six months, I did an A/B test again... just to see if my brain/ears were fooling me. The difference was again huge... the Heppners all over the Polks. Now while those Polks are far from top of the line (which I can't/won't afford), the Heppners in OBs still sound super to me. I wrote about re-doing the A/B test a few months ago in this thread.

As mentioned recently in this thread, I augment the bass/low end with a subwoofer. Once in awhile though, I will turn off the sub, and put the "loudness" on with just the Heppners playing. It takes a moment to get past the reduction in bass, but after several minutes, I am enjoying the sound a lot.

I'm not trying to sell you on the Heppners.. just sharing my experience. Many pairs of ears hear differently. As I mentioned, I tried several different pairs of 8" speakers,... modern and vintage... and none were expensive.

If I were to start looking again at some full rangers, I'd look on eBay at 8" and 10" vintage speakers (4 or 8 ohm usually). There are 8 & 10 inch Wolverines which some people like. But there could be lots of unfamiliar names of speaker manufacturers you might run into... if inexpensive enough (I'd never ever heard of Heppner speakers before). Utah speakers are sought after, too.

https://www.ebay.com/itm/Heppner-6-...872358?hash=item3af49a8c66:g:P8AAAOSwThtZ5TEf
That's another Heppner... he's calling it a 6" speaker, but with that 24398-0, I'm pretty sure it's another 8 incher. The small tear in the cone can easily be repaired using some ordinary wood glue dabbed on front and back of the cone... I've done it with many speakers, and doesn't seem to affect performance.

I am by no means any "expert" on OBs in contrast to many others in this extensive thread.

I hope others will chime in here with their experience with the 8 and 10 inches full rangers. Maybe they won't be as "wordy" as I.[/QUOTE]
 
So I have been baby-stepping with my experimental OBs for just over a week now. I ordered a pair of Betsy drivers, which should arrive Tuesday. I also got the jig saw back out today and created pseudo-caintuck shapes out of my 24"X24" square baffles. I penciled in a barrel shape that tapers from 12" across at top and bottom of each baffle and flares to 20" in the middles. I cut the first side and then used that piece to draw in and make the rest of the cuts. I also had to make the speaker cut-outs a little larger for the Betsys. Considering I free-handed the cuts, all went well and after some sanding the baffles look pretty nice IMO.

I re-mounted the Visaton BG-20s to run until the Betsys get here and they sounded good to me, maybe better in the smaller, shaped baffles as compared to the original 24"X24" squares. When I mounted them originally, I used thin weatherstripping as a sort of "gasket" but this time I simply mated them to the wood and screwed them in. I also bought a Behringer mini EQ to play around with, knocking down the 2K-4K frequencies a bit to kill a touch of the shoutiness of the Visatons.

First, I have to say that this experimentation is great fun, and done on the cheap, which makes it better. I'm very excited to try the Betsy drivers this week, as they seem to draw high praise. If I enjoy them as much as I hope, I'll make a pair of more-stout baffles (currently 1/2 red oak ply) and/or will consider adding eminence 12" or 15" woofers. I have zero idea how to set-up/build crossovers or line filters, so I may have to learn how that stuff works.

For those who are interested in the Visatons, I should have a good comparison between them and the Betsys in the next week or two.
 
The FR drivers are not picky about the size of the baffle. You will need woofers if you want any appreciable bass from OB. If you go with 15" Eminence woofers use the Beta 15.
 
So my personal journey into OB continues. Today a set of Wild Burro Betsy drivers arrived. I removed the Visaton BG-20s from my experimental Caintuck-shaped baffles, drilled the extra holes needed to mount the Betsys and mounted them. I'll make a couple of observations here and then later will post more comprehensive thoughts.

First, the Betsys are lighter than the BG-20s, the magnet assembly seeming thinner to my eye. They seem very well made, with deeper frame and more throat on the whizzer cone than the BG-20s. The cone itself is less deep on the Betsys as well, with flatter dust cap, and the material they use on the outer cone, the area where it flexes next to the frame, is different as well. The Betsys require eight mounting holes each versus four for the Visatons.

As far as sound impressions, the Visatons were a bit shouty from the first minute they were installed, while the Betsys are remarkably "coherent" by comparison. With room correction and bass assist from a Yamaha sub, the Visatons were pretty pleasing to me. However, the Betsy drivers sound much more agreeable, and only a few minutes into their lives. The Betsy drivers (and I've read this before many times) sound musical and agile in ways that the Visatons cannot match, with coherence being the word that keeps on coming to mind.

None of this is new to anyone who has knowledge of these drivers, but I hadn't seen many comparisons that included the BG-20s. FWIW, the Visatons are very affordable, about $30 per on PE. For the price they seem very well built, robust in comparison to the Betsys. Their sound seems good, but not nearly as right to my ear as the Betsys right out of the box. I'm going to give the Betsys a few weeks to break in and mess around with EQ, room correction and bass support. Right now I'm crossing to the sub at 90Hz but may bump that to 100hz. Once I'm happy, I'll order thicker plywood (currently using 1/2 inch) and fashion a "permanent" pair of OBs for these drivers if all continues to go well with them.
 
DavidTT said:
So my personal journey into OB continues. Today a set of Wild Burro Betsy drivers arrived. I removed the Visaton BG-20s from my experimental Caintuck-shaped baffles, drilled the extra holes needed to mount the Betsys and mounted them. I'll make a couple of observations here and then later will post more comprehensive thoughts.

First, the Betsys are lighter than the BG-20s, the magnet assembly seeming thinner to my eye. They seem very well made, with deeper frame and more throat on the whizzer cone than the BG-20s. The cone itself is less deep on the Betsys as well, with flatter dust cap, and the material they use on the outer cone, the area where it flexes next to the frame, is different as well. The Betsys require eight mounting holes each versus four for the Visatons.

As far as sound impressions, the Visatons were a bit shouty from the first minute they were installed, while the Betsys are remarkably "coherent" by comparison. With room correction and bass assist from a Yamaha sub, the Visatons were pretty pleasing to me. However, the Betsy drivers sound much more agreeable, and only a few minutes into their lives. The Betsy drivers (and I've read this before many times) sound musical and agile in ways that the Visatons cannot match, with coherence being the word that keeps on coming to mind.

None of this is new to anyone who has knowledge of these drivers, but I hadn't seen many comparisons that included the BG-20s. FWIW, the Visatons are very affordable, about $30 per on PE. For the price they seem very well built, robust in comparison to the Betsys. Their sound seems good, but not nearly as right to my ear as the Betsys right out of the box. I'm going to give the Betsys a few weeks to break in and mess around with EQ, room correction and bass support. Right now I'm crossing to the sub at 90Hz but may bump that to 100hz. Once I'm happy, I'll order thicker plywood (currently using 1/2 inch) and fashion a "permanent" pair of OBs for these drivers if all continues to go well with them.
Click to expand...

I really like the Betsy's and glad you feel the same way.
 
DavidTT said:
So I have been baby-stepping with my experimental OBs for just over a week now. I ordered a pair of Betsy drivers, which should arrive Tuesday. I also got the jig saw back out today and created pseudo-caintuck shapes out of my 24"X24" square baffles. I penciled in a barrel shape that tapers from 12" across at top and bottom of each baffle and flares to 20" in the middles. I cut the first side and then used that piece to draw in and make the rest of the cuts. I also had to make the speaker cut-outs a little larger for the Betsys. Considering I free-handed the cuts, all went well and after some sanding the baffles look pretty nice IMO.

I re-mounted the Visaton BG-20s to run until the Betsys get here and they sounded good to me, maybe better in the smaller, shaped baffles as compared to the original 24"X24" squares. When I mounted them originally, I used thin weatherstripping as a sort of "gasket" but this time I simply mated them to the wood and screwed them in. I also bought a Behringer mini EQ to play around with, knocking down the 2K-4K frequencies a bit to kill a touch of the shoutiness of the Visatons.

First, I have to say that this experimentation is great fun, and done on the cheap, which makes it better. I'm very excited to try the Betsy drivers this week, as they seem to draw high praise. If I enjoy them as much as I hope, I'll make a pair of more-stout baffles (currently 1/2 red oak ply) and/or will consider adding eminence 12" or 15" woofers. I have zero idea how to set-up/build crossovers or line filters, so I may have to learn how that stuff works.

For those who are interested in the Visatons, I should have a good comparison between them and the Betsys in the next week or two.
Click to expand...
If you get a chance, take some pics... we love pics here!!
 
I've been enjoying the Betsy/Caintuck style OBs this week. I'm very interested in building a "final" (yeah, right!) pair using the Betsys and Eminence Alpha 12" or 15" drivers, one per side mounted underneath the Betsys, similar to the "Betsy and Buck" configuration that Caintuck sells. I am planning to run these using a simple Yamaha AVR with small Yamaha sub for support, but if I'm going to cut new baffles I'd like to add the larger woofers unless it adds a lot of complexity.

1) Is it possible to run both sets of drivers using the AVR speaker outputs alone? My AVR puts out 100W but is quite simple and includes just one set of speaker outs plus a sub/LFE out. I'd like to avoid bi-amping and plate amps if at all possible.
2) If I need to add a crossover, what frequency would be best? For some reason I'm thinking about low pass 200 hz for the 15As.
3) Is there a simple, cheap and dummy-proof way to add a crossover/filter for these drivers?
4) Can someone please describe in the simplest language possible how the wiring would go?

In my ignorance, I considered splitting the speaker signals coming from the AVR, adding Harrison FMOD low pass modules to the cables connecting to the 15As, and running the Betsys full range. It can't be that simple right?

I got into OB partly because of the simplicity of the FR driver aspect, and really want to avoid much added complexity. What's the best way to keep it simple in my intended application?

Thanks in advance!
 
You'll need one amp for the Betsy's and a separate amp for the 15A's. I would run the Betsy's full range with no crossover but you'll need something to filter the highs from the 15A woofers. That could be a cheap electronic crossover, fixed passives like the Harrison Labs Fmods ( maybe 70Hz - more like an active as they install up stream of the amp ). If you don't have a second amp then consider a low power sub plate amp which has a built in crossover or something like the link below. Can't speak to how well it works but Amazon will take anything back on their dime.

https://www.amazon.com/OSD-Audio-SM...F8&qid=1524308647&sr=8-1&keywords=OSD+sub+amp
 
Last edited:
Thanks PG for your continued input in this thread. If going to plate amp route, but one wants to just buy one plate amp, I get confused about wiring. I've seen a lot of discussion of the Dayton SA100, which is affordable and gets good reviews, but I'm trying to understand the best/simplest way to set up wiring. Since I'm using an AVR with LFE signal out and assignable crossover in the amp itself, I would guess I have several options for wiring:

1) I could connect main amp speaker-outs to the high level inputs on the plate amp and go from there. This would allow easy control of gain and crossover from the plate amp.
2) I wonder about simply sending the LFE signal to the plate amp and then branching the single plate amp output to both 15As. This would allow the speaker outs to go from AVR to Betsys, and the output levels would be controlled from the AVR. The SA100's low level output would also allow the continued use of a separate powered sub if desired. Workable?
3) Can one simply split the plate amp output and send it off to both woofers? I've read different things in the past about splitting speaker signals and whether it's a good idea.

As I work this through in my (feeble) mind, I picture the #2 option above, where I would place the plate amp directly behind the AVR, run a very short RCA from the LFE out on the AVR to the SA100, splitting the output to feed both Eminence drivers. I would essentially bypass the crossover in the plate amp, using instead the crossover settings in the AVR. I would run normal signal from AVR speaker out to the Betsys, giving me controllability of gain on the woofers, crossover via the AVR, and a potentially tidy set of joined cable runs from behind the AVR and plate amp.

Unless you advise to the contrary, that is the solution that seems the best combo of simple and workable for me at this point. The SA100 offers flexibility for the future, in the event I decide to up my game and apply power to the Betsys using a small tube amp in the future. Does this all seem reasonable as I propose or am I missing something?

Poultrygeist said:
You'll need one amp for the Betsy's and a separate amp for the 15A's. I would run the Betsy's full range with no crossover but you'll need something to filter the highs from the 15A woofers. That could be a cheap electronic crossover, fixed passives like the Harrison Labs Fmods ( maybe 70Hz ). If you don't have a second amp then consider a low power sub plate amp which has a built in crossover or something like the link below. Can't speak to how well it works but Amazon will take anything back on their dime.

https://www.amazon.com/OSD-Audio-SM...F8&qid=1524308647&sr=8-1&keywords=OSD+sub+amp
Click to expand...
 
This picture shows two bucket subs being powered by a single sub plate amp ( mounted in the wood case ) which is what I often do with OB woofers. Plate amps are mono and have one channel ( one red and one black wire ). You double up on the speaker wires from the plate amp to the woofers which is a good thing as the load from the Alphas go from 8 ohms to 4 ohms. The plate amp's power increases accordingly.

Since plate amps are designed to be attached to a subwoofer box using one independently requires an open frame. You can use a box with a cut out or anything that allows the amp to be elevated so it can sit level. Plate amps come with one black wire and one red wire which are connected to terminals mounted on the back of the frame or box.

P5080061.jpg
 
Underside view of a plate amp which is held in place with small screws. The plate has a lip with screw holes already drilled. Only wiring required is connecting one red and one black wire to the terminals you provide and mount on the back. You can't see the terminals as they're wrapped with electrical tape.

PC120003.jpg
 
Thanks much for the input PG! I ordered a pair of 15As, which were available from amazon for $65 each, shipped, which seemed pretty doable. Next will be another couple of play project boards, this time 3/4". I'll have to consider best practices for using/mounting a plate amp since I'm not able to fashion a nice enclosure like you fabricated in those pictures. I'll figure something out, but have the feeling that the 15As will provide some serious punch in baffles with the Betsys. Thanks again. More to follow.
 
Michaels or any craft store would have an assortment of wooden boxes or frames that could be used to mount a plate amp.

84421d6422e8af1e8ae3c77589e81f07--wooden-shadow-box-shadow-box-frames.jpg
 
I really enjoyed this version of the Betsy and Buck. For the Alpha filters I used a passive crossover from PE. Seems like it was 8ohm 70Hz? I drove the Betsy's with an APPJ SET amp with a ss amp powering the Alpha woofers. The cork backing was made from Ikea placemats.

PB230008.jpg
 
Been reading through a bunch of the OB posts and I'm intrigued.

I've tried some EV 12TRXB and EV Pro12B in a 14' x 16' bedroom, just open speakers with no baffles. Also running a typical sub-woofer with speaker level pass-through to the EVs.

They do sound quite different than speakers with enclosures.

Will even a small baffle help the lower mids? Something as small as 14" w x 18" tall?

I'm running the sub with the crossover maxed at 200 hz, but I'm still missing a lot of lower-mids and upper bass. Mostly upper bass guitar and the lowest 6-string guitar notes. I'm using recordings I know well, and I know what's not there, or so subdued you can't really hear it unless you know to listen for it. This stuff is below 200 Hz.

Maybe I just need a better sub? Although It works very well with my small conventional speakers (Music Hall Marimbas).

I don't have room for huge baffles in this room. Maybe I need to stick with box speakers in this room and go play around in a larger room with the OB experiments.
 
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