Hi hazmania,

Yes would love to see pictures. Going to build some. Been to cold and my garage is to full. That will be solved soon. It will all be heading north. Have to open up my north cottage in the woods. Can't leave too much up there in the winter.

Did put some F15's into some butcher block counter tops. Really like them a lot!

Beautiful!  How do you like the sound?  Have you played with tilting them back?

Hey Steve,

I have a couple of questions.. I read thru this thread last night. It's a lot to digest. Maybe this was answered already, apologies if that's the case. It's easy to miss something after reading that many pages!

-What happened to the foam on the back of the speaker base? I don't see it in the pictures on the product pages.

-Is there or do you have any plans to accommodate the lean back into the design itself? Or is/will it continue to be a user add-on?

- Do the tonewood properties come into play here on the baffles?
(There's some tonewood info over on the guitar lobby website - can't post links yet)

Thanks!

Ron

(New to THIS audio forum and awaiting my Decware Intergrated Amp  ;) )

edit: added tonewood question

-  Hello ,  can anyone tell me the approximate weight of a pair of ZF15L speakers??

-  I realize it will vary a little based on what kind of wood is used, I'm just trying to figure out how hard they will be to move around,


Thank you , Dean

Thanks all for the compliments. To answer your questions, they do sound great. I am using an Audio Research tube preamp but am on the list for a SE84UFO2 which will be more appropriate than my 150 watts per channel Odyssey monoblocks. I DID tilt them back with about a 1 1/2" lift in order to raise the sound stage. I didn't really notice any loss of bass at that level (they did at 2") after dialing them into that height. Now I am working on a solid "sled" to fill in the space created by the lift. I don't know if this will make a difference sound-wise or just on looks. I don't remember anyone else bothering. Finally, I used 8/4 hard maple finished at 1 1/2" on everything and finshed with two coats of Rubio Monocoat. Rubio Monocoat is actually a floor finish (you can buy online). It really makes woodgrain pop and is a foolproof application. The downside is one coat of Monocoat is a flat finish. 2 coats of Monocoat (lol) helps bring it to satin. The price seems high for what you receive but when I factor in time and sanding between coats saved I think it is a good value, especially for a guy like me with a dusty 1/2 of a two car garage in which to do everything. I can't imagine breaking out my compressor and spraying poly on anything going forward.

My DIY are about 100lbs each but they slide easily on my wood floors since I put felt pads under them.  I have maybe 35lbs of ballast on each so without they are more like 60 to 70 lbs each.  Not something you'll pick up.  Plus they are incredibly bulky.

hallcon83,

I have built a open baffle kind of like you are talking about, just with different drivers.



I'm using 8" Tang Band full rangers and 15" Eminence woofers.
Actually there are 2 of the 15" in each speaker as there is another baffle behind the front baffle.

You can see the second baffle in this picture.

 

Sorry, I'm being lazy and just using some old pictures.

To paste a web based picture
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Thanks Dana

There are many baffles around now, they all go back to Randys invention and have been magnified.
I have looked at many sizes and thought, it would be nice to compare them all in a table.
So I have made up an excel file, where you can play with magnification factors until you get the right size for your room.
The sheet calculates height, width, midpoint cutout from the bottom and radius.
blue:    default size of the original Betsys.
           Because Randy has told 17.5" and 18" for width, there are 2 tables.
yellow: These are the results, read only, inches and cm.
green:  There you can fill in factors you like and give the baffles a name.
Its fun to play with the table!

download the file, excel or/and numbers from this link:
https://www.mycloud.ch/s/S00B48FEA3071CB12B8C1D59DD189115076470E8FB4

André

This thread describing Steve's Big Betsy project is the reason I have two brand new F15 drivers chomping at their bits right now.

Instead of beginning a new thread, I am hoping that I can post some progressive results in this thread.

I notice it has gone way off topic in several directions.
I'm OK with all that, but, since I am in this boat like many of the curious, I thought that keeping this thread going would be more beneficial than another diverse arrogantly placed self absorbing new thread.

I spent half the morning cutting the curved sides of the baffle design that Steve posted early in this thread. I have decided to go the full size 42" concept, not reducing it for my small room. I thought about this a lot!

I even made cardboard cutouts to better guage what to expect in my small room. 42 it is.
I'm leaving the alchemy out for now, going with what works.

Not sure what the extra 1/16th inch in heigth was about, but I kept it.
Some lengthy sanding to the marks is left. My beginner trial baffles I can lift, plywood and MDF sandwiches glued and drying for three days now, and I used my band saw, which I have finally uncluttered enough to have walking space around it.
In fact, I clamped them together and slowly sawed both at the same time. I mean why else does one own a band saw?

Centers are marked at published height and router work will be next after some more sanding. I plan to front mount the drivers with an inset for the frames. I've seen some done with rear mounting and cute rounding of the front. Nice looking with great wood, but I am building a test baffle not the real thing.

From the early remarks Steve posted, there does not seem to be any back tilt dialed in from the beginning. I am making mine up square with no tilt. Adding tilt if wanted once they are active.

Steve mentioned in the informative parts of this thread that an average guy could make something partway with average skills.
I am attempting.

Back to my "Honey, overdue" list for the afternoon. Plant stands, ceiling hangers, even an IKEA assembly. My daughter is doing the IKEA work, but I will manage following instructions, using the right tool, not breaking things, etc.

Great idea, but my daughter already claimed the cutouts for her macrame '70s looking shelf things she makes.


Wife is fairly happy, but I will only get a few days with unfinished project things inside. Pushed it a little with my last mock up.
I plan to fool her and paint these before I bring them in, even to my own room.
You need at least two wheels to keep the wagon rolling and she is a solid one. It's up to me to hold up my side.

1/4 inch spiral solid carbide

Holy Schnikies! my F-15s in 36" high single thick black walnut, and just tonight hooked up the first of two "Bucket Subs" on a 300 watt plate amp...... good stuff...  Anyone else here doing Bucket Subs?

Steve T

https://www.transcendentsound.com/bucket-sub.html

sounds great with my F-15s....

Steve T

Loving this thread. Thank you for all the valuable information. I'm prepping to start my own Betsy-esque build with my father.

I've been sitting on a couple of F15s and W15s for a few years now and now I really need to get moving on a project. In the meantime, since Covid times, timber is in short supply here in Australia and prices have blown out enormously. So much so that I've discounted the feasibility of using hardwood for a Big Betsy design. Thick plywood is also very expensive now. MDF is still quite reasonable, so I've decided to go down that path. The only issue is that the thickest MDF I can source is only 32mm. I can create additional constrained layer damping by bonding an additional 6-9mm thick MDF or ply panel to the back using an industrial grade rubberised glue.

Currently I use a pair of transmission line subwoofers with 10" Peerless drivers. However, I've recently discovered that the bass frequencies of vinyl records are summed to mono, so there probably is no real benefit in having two OB subs powered by W15s. Is this even true? Any thoughts on one or two W15 Betsy subs for a 5m x 9m room with 3.5m ceiling?

Here are what I've been listening to up until now. I recycled a French Oak wine barrel, reshaping the staves slightly for a tighter curve. These sound amazing with the Lii Audio Fast 8s driven by my 2.3w Spud Kit 6CL6 amp with mil-spec tubes.


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