# "Speakers by Bob"



## Bob in St. Louis (Jan 24, 2012)

Ok fellas.....
I've got my ten posts in, so I'm now able to post some photos of the things I've made.
I belong to a few audio and home theater related forums where "build threads" of equipment are a very long and drawn out ordeal taking weeks, sometime months before they're finished. Usually they're nothing more than the typical "look at me" threads, sometimes you're building something for someone else.

Either way, the audio guys enjoy a good build thread that has chronicled the process of assembling a piece of equipment, or...dare I say...."art"....... 

So please tell me if I've overstepped my bounds, or offended anyone.
But I have a passion for building things out of wood, photography, and chatting with folks on forums. So I find it a tad natural to make a short story long when it comes to starting threads and showing pictures.....

Here we go....

A fellow in Kentucky asked if I'd build him a set of speakers using some solid cherry planks that he sourced and shipped to me in St. Louis. 
I sourced the "drivers" (technically, "drivers" are the round black things inside a speaker that create the sound you hear, the "speaker", is the "unit" in it's entirety.)

So without much (more) pomp and circumstance, here's the build. Not much required in the way of words, as you fellas will be able to follow from a technical perspective very easily. The build thread I had on the other places are more of a "step by step" with explanations of what you're seeing as I'm going along.

The photographic journey starts from where the UPS tractor trailer meets me at a local school (because I live on a dead end road that he wouldn't go down)...to the final shipped product:


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## Bob in St. Louis (Jan 24, 2012)




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## Bob in St. Louis (Jan 24, 2012)




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## Bob in St. Louis (Jan 24, 2012)

By the way.......That driver is 15" in diameter!
For perspective, you can see the holes in the peg board, and the hammer on the right side.

Bob


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## Bob in St. Louis (Jan 24, 2012)

The layers of the three speakers I'm building.
The right, left and center channel speakers for this fellas audio/home theater room:


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## Bob in St. Louis (Jan 24, 2012)

Sand "filling" will absorb acoustic vibrations and make the unit sound better, overall.
Layers one and two...clamped:


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## Bob in St. Louis (Jan 24, 2012)

Ready for the final wood layer, entombing the sand in it's new home, forever.
Layers one and two are glued together, filled with sand and ready to be sealed up with the third layer of cherry:


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## Bob in St. Louis (Jan 24, 2012)

The legs to hold up the 5' tall speaker were made from the scrap of the 15" circle cutouts. You can see the prototypes (made from MDF) on the far right and left sides.


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## Bob in St. Louis (Jan 24, 2012)

The actual cherry legs:


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## Bob in St. Louis (Jan 24, 2012)

And the final product:


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## Bob in St. Louis (Jan 24, 2012)

Ok.....

So, that's what I'm all about fellas.
I found this forum and it seemed like a nice place for me to land with regard to woodworking topics. Both to share, and learn.

I sincerely hope you can find a place for me to "nest" among the experts here.
I hope you enjoyed looking at the pictures (cause I've got a lot more haha).

Bob


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## Bob in St. Louis (Jan 24, 2012)

By the way.......

If you're really bored (not "board") and want to see all 50 pictures I shot during the build of these three speakers, >> here's the slideshow << of the entire process.

Bob


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## papawd (Jan 5, 2011)

Nice job does the sand act as a bass suppression type???


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## TheOakDude (Oct 11, 2011)

Amazing, really beautiful design. Interesting use of sand. I am really curious as to how these sound...ie without a cabinet surrounding them.. What make are the drivers???active or passive crossovers and at what freq do you cross???What power supply ie seperate amps for each driver or an amp for each stand??
very impressed with the look and as I say would love to actually hear them.
thanks
Paul


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## N'awlins77 (Feb 25, 2011)

Wow, very nice Bob. So speakers --- I mean drivers, don't have to be in-cased in wood? The technology of speakers, like everything else has changed over the years. Back in the day, LOL, we called the parts of a speaker the woofer, tweeter and mid-range. As with everything else, times have changed.


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## Jmpreiks (Jan 2, 2012)

Nice work, those are some big, heavy speaker stands! One question I have is are those some special speakers that don't need to be enclosed? I thought speakers need to have a certain volume of air behind them to perform optimally. Whatever they are, that does not look like a cheap build!


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## Bob in St. Louis (Jan 24, 2012)

Thanks for the complements guys!

papawd - Yes, the sand vibrates, thereby dampening the overall speaker. you can pound the face of the unit like you would pound your fist on a desk and feel a big difference compared to a non-dampened design. Technically speaking, when a speaker vibrates, it "smears" the sound, just a wee little bit making it sound muddy and not as clear as it should. There are many ways to "brace" a speaker from moving, sand absorbing that vibration is just one way. 

TheOakDude - The brand of drivers is "Hawthorne Audio", they're located here in the states. Although there are a few guys on their forum that are from NZ, so there may be a possibility you could hear them. The compression tweeter on top that is screwed into the rear of the coaxial driver is crossed at 1200 Hertz (if I recall correctly) and is passively crossed. A lot of the guys use modern, or restored vintage tube amplifiers to drive them.
The lower bass augmenting drivers are actively crossed. Some guys cross them as low 60 Hz, some as high as 100. Due to the power requirements of these lower drivers, everybody uses solid state Class D amps to power them.

N'awlins77 - You're still correct. There's still a woofer, mid, and tweet, it's just that we lump all those into the generic term "driver", and the entire unit would be the speaker.

Jmpreiks - Yea, they're heavy alright. ha ha
I weighed them when I built them, and can't recall what they were. If memory serves, they're something like 125 pounds?
You right, all drivers have to have a certain amount of air behind them. Some works best with a little, some a lot, and some (like these) need all they can get.

Do a Google search for "Open Baffle". That's the most common term.


So....I've got more pictures of other builds. You guys wanna see? 
Bob


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## kp91 (Sep 10, 2004)

Cool speakers, Bob. A lot different than the ones I made. I remember having to match the desired fequency with the internal volume of the box, the size of the port, etc... 

That's a lot sleeker design!

Neat project.


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## waho6o9 (Apr 4, 2010)

Thanks for posting Bob, very interesting way of making speakers. More pictures when you have time. Thanks again.


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## Bob in St. Louis (Jan 24, 2012)

Bob in St. Louis said:


> Although there are a few guys on their forum that are from NZ, ......


Umm...whoops. Sorry, I just noticed that little mistake.
Let's just say there are even more of these drivers in the UK, than there is in NZ. 
Sorry, about that Paul.

Bob


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## Cherryville Chuck (Sep 28, 2010)

I remember when Bose 901s first came out with the 1 speaker direct/ 8 speaker reflected design. Without the box to aim these, do you get a lot of reflected sound?


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## wbh1963 (Oct 11, 2011)

Hi Bob,

Thanks for sharing your 'build' with us. I look forward to seeing more of your creations.


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## rwl7532 (Sep 8, 2011)

Do you have a lathe?
I see bowls hidden in all those circle cutouts.


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## Bob in St. Louis (Jan 24, 2012)

Charles, Those olf 901's are respected highly among the audiophiles (unlike the new Bose stuff... ha ha), I've never heard a pair but would like to someday.

Bill, Thank you for the kind words. Since there's interest, I'll start another thread for some of the other speakers I've built.

Ralph, No.... I don't have a lathe, but would LOVE to have one. This particular build has yielded exactly (12) 15" diameter circles. Combining those with other builds, I have quite the collection. In fact, I even have some 18" circles. ha ha
There's another recently thread here where a fellow was making Baltic Birch Ply bowls. Love them.

Bob


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