Thanks Dank👍🏼

Bosendorfer Imperial plays a full octave lower than the standard 88 key piano.

Here is a link to some Bosendorfer recordings from Delos so the sound is great!
https://delosmusic.com/artist/carol-rosenberger

She is associated financially in some way so I have always assumed that had an influence on her being recorded by Delos on her own personal Bosendorfer Imperial.

Quote:


I posted a page a long time ago that showed an experiment that I used as an example of why it's so difficult to A/B stuff, even blindly. In the experiment there is this soundbite of crazy hash/white noise and buried in there somewhere is a voice...you simply can't hear anything but hash. Then they have you play the same track with the woman's voice brought slightly to the forefront. From that point forward, now that you've heard the woman's voice, you can go back to that first file you played and the womans voice pops right out!

Basically your brain remembers that audio pattern and fills in the blanks for you when you listen to the first buried voice track.

Steve and I have talked about this with harmonics and such. I hear people all the time saying "I'm too old to hear that frequency so why bother", or in my case I have a bite taken out of my audio spectrum, and I'm probably not hearing much past 15k anymore...but I still have amazing hearing. It's not because I have "Golden Ears", but because the I have a good processor (brain) recognizing patterns and filling in the blanks.  

That's also why I think it's so very important to hear music live, and expose yourself to as much music and sound (in general) - You need to sample those patterns so you *know* what they sound like and develop your audio palate.

You are cutting with a router?  If so, just take shallow cuts (1/8") and watch that the drop doesn't break off when the cut get close to done.  If you have a band saw then cutting before it's all glued up works well.  Either way you'll probably spend more time setting up and making jigs.  Oh, I fortunately drew center lines on my blanks before I cut the radii.  Once they are cut it's hard to locate yourself on the barrel shape.

That's going to be a nice baffle.

I, too probably can't hear higher than 14,000 Hurts but I enjoy music a lot.

Palo,
Shellac is the only way to finish oak. Maybe 3 or 4 coats of Amber Shellac will make it pop.
Quick and easy.

Donnie, does shellac come in black?

Archie, I find that my router cuts are much better when I go in the direction that the bit is turning.  I discovered going the opposite direction to not work well at all on ply.

I was going to flush mount the driver, but it sounds like I better be pretty careful with that or just surface mount it.  I have missed on that cut as well and not had enough for the screws to bite into as you said.

Alright let's discuss climb milling vs. conventional milling.
Climb milling is where the cutter "pulls" itself into the material, the router seems to power itself.
Conventional milling is where the cutter "pushes" back to you, the router takes more pressure to cut.
Climb milling will give you a cleaner cut because the chip is thinning as you cut along, but it is much less forgiving. Your setup has to be rigid and you have to control the cut better because it is easy to over feed the cutter.
Conventional milling is a little more forgiving but causes more heat because the chip is thickening as you cut.
Sharp tools are your friend, so sharp that you cut you eyes looking at them.
I could get real technical, but I'll save you the agony.

Palomino, I think you are thinking of the correct ones. They do take more area up. You have to drill the hole larger to install them, but then you use machine screws and can take the drivers off and put them back on without worrying about the wood wearing out. The hurricane nuts have a back plate to them so when you screw something down you are not only pulling on the thread but also on the back of the wood. They are different than just brass threaded inserts.

I have the machine screws that you use the allen wrench to tighten on my cottage baffles and on the ones that I used for my low boy temporary baffle for the F15.

I looked up hurricane nuts and that isn't what I have been using.  I have been using these:  https://www.parts-express.com/1-4-20-deluxe-6-prong-t-nuts-50-pcs--081-1090?utm_...  Similar but not the same thing.

My wood is just wide enough so as I swing the arc, it will pass out of the wood when I reach dead center if that makes any sense.

So I like your suggestion of "flipping" but I don't have a flush trim bit.  My tool man (el presidente) left town and took his tools with him.

ZYGI, why is that? Is it just for spiral bits?  I'm guessing it must be since the flush trim bit works with an open side.  What happens if the bit cuts on just one side?

Archie, if you are climb cutting and you are out of the material on the opposite side of the climb cut,  there is a possibility that it can gain traction, so to speak, and take off on you. Not only very dangerous unless you are used to it, but as it bits in it usually takes chunks out wit it.

All it takes, if you are using the circle cutting jig and its open sided is the jig flexes from the operator readjusting his position or his hands and the bit digs in,  you can not just pull the bit out away from the wood to stop it. It is sort of trapped, and goes.

My main reason for flipping and using a flush trim bit, is this...if you only cut half way through, the rest of the off cut is still intact,  there is no way you can take a huge chuck out like what happened to Steve on his baffles.  

If I were to make two baffles, (and I'm guessing for a stereo piar that would be the case) I would only cut the arc on one side of one baffle, the saw off the excess from the other edges, and flush trim to the first baffle, using it as your template.

Just my way of doing things. Nothing worse than having all your stock glued up and have a major disaster with tear out.

Donnie...Machinist mill, woodworkers cut....

I guess I haven't experienced this as I don't do much pattern cutting with a router.  I am familiar with the router taking off and moving away from the work if I go the wrong direction.  Free handing hinge mortises takes an iron grip for sure.  It must also be a function of how much you're taking off since flush trim bits work only one side, by definition.

Zygi,
Mea Culpa. Lol!
This wood cutting stuff is new to me!
The physics of it are the same but the terminology sure is different.
The main thing is how the chip is formed and how the mechanical reactions are handled.
Like I said before, I could bore the living shit out of all of you talking about chip formation, chip loads, surface footage and much more esoteric things.
I sure do like listening to a true artist describe their art. My strength has always been the science of cutting materials, I've never had the talent of a artist.
"Perfection can never be attained, but it sure is fun chasing it".

I've had my F15s for a week and while they are excellent I think I'm going to focus on other projects.  If anyone is interested in buying a like-new pair of drivers send me a PM.

Welcome to the forum!  ... and the family!

Steve

Nice work Pal!  And how do they sound?

Palomino - I can't believe you gave up staining the deck... what a putz. . I could have been building baffles today too but I did the right thing and installed a new tankless water heater.  You should of seen me towards the end of the day, on my 6th trip back to Menards for stuff when I discovered 3 feet of 3 inch vent pipe (a 90, a pair of 45's and a single 12 inch straight piece) cost another $270.  I did some street graffiti with the 72 Monte on the way home to make myself feel better... and it I wasn't so tired I'd be out there mounting the drivers in the new baffles right now.

Steve

Looks like I made the right call.  Wouldn't want to have the deck get rain less than 24 hours after staining it.  Also, now I can listen to the Big Betsy's today without guilt.




I'm in that state of wow so maybe you guys can help me sort out what I am hearing, feeling and measuring.




First of all, the big Betsy's are BIG.  They dominate my small 16X12 listening room.  They aren't really taller than other speakers I have had in here, but they are wider.

Does it matter?  Not when I close my eyes.  They completely disappear.

And the F15s sound completely different in the big baffles vs the low boys.  The hit Steve talks about is definitely there in spades.  And you feel the bass much more in your chest.  Like every song with any bass you feel it.  I am listening to a guitar song accompanied by string bass and feel it.

I'm thinking, this HAS to be digging deeper so after about an hour I break out the measurement mic and REW.  

Identical bass under 100HZ.  I think, how can this be?  So I look at 100-200Hz and the response has greatly flattened out.  No dip like I saw before.  A little louder in this section, but mostly it has flattened out the response.

The only other significant measurement difference is above 10K where the highs are definitely more extended.

But the speakers sound completely different.  I would definitely agree with Steve's comment about the whole baffle being a transducer.  You just feel the music more.  Its like a giant wave hitting you and your body buzzes.

So, I am using 1.1" stair treads glued together. I'd give myself a solid B on woodwork.  I decided to flush mount them and went a little deeper than I should have.  I ran one of the mounting screws out the back and I did find a a ding on the back side edge of one baffle where it got away from me.  All of these can be addressed.

Does this experiment suggest that a lighter wood version of the Big Betsy would give you 80-90% of the heavy wood version?  I like to think so.

I may not finish these and bring them to Decfest for comparison.  That way if they take a few knocks, I can sand them out.

So I am pretty impressed and feel the time and expense was worth it.

Thanks to Steve and Randy for the design and inspiration.  These sound (and feel) really good.

My footers are 11” long solid oak blocks that are around 3” by 2.5”. I repurposed some desk legs a friend in the office business gave me.

They just run 90 degrees out from the baffles secured by a lag screw.  I used a forester bit to drill the holes for the lag bolt.  I will cover these holes with a 3/4 wood plug I got at the hardwood store once I finish the baffles.  

I may also put some in front as Steve did.  I was going to and I screwed up one of the 4” blocks when I was cutting the table leg on the miter saw.

I may beef up the supports at some point.

I did score the handles for $12.  Supposed to get here Thursday.

Randy mentioned knee rattling quote.   I like the nice body buzz these drivers give.

There are design points that it would be interesting to see what effect/difference they make so I hope you get to take these to Decfest.  I'll have the weights early next week to try.  I really like the look of your oak.  I keep toying with the idea of making prettier baffles down the road.

Well, my kneecaps were definitely rock'n!  (I wonder what their resonant frequency is?)

Installing the drivers and handles.

Steve

Steve,
Those are awesome. If aesthetics were the only thing that guided great sound, those would knock it out of the park. I can’t get over how that heavy wood just looks like it’s gotta be great.
Best,
Scott

A nice backlit effect showing off how little the three spokes of the driver frame reflect the sound.

Steve