Author Topic: My build of a pair of HawthorneAudio Sterling Duets  (Read 30771 times)

Offline Bob in St. Louis

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My build of a pair of HawthorneAudio Sterling Duets
« on: December 05, 2011, 03:32:51 PM »
Hey, you guys wanna see me build some open baffle speakers?

If so, then read on....
If not, then tell me to buzz off.  :lol:

I'm posting this piggy-back on the build thread on the manufactures site, so I could be called a fanboy shill, but I thought you might like to see some sawdust.

Anyway..... Here goes.....

Tony, A local St. Louis fella had lurked long enough on the HawthorneAudio site that he contacted me about listening to my system. Seem after hearing us (fanboys) chat about it, he was interested in hearing the Sterlings Duets for himself. So of course I brought him into my home and gave him a big tall glass of Hawthorne Audio kool-ade.   8)

Tony is a great guy with an interesting taste in music. Suffice it to say that he expanded my musical horizons just a wee bit:shock:
After tolerating a few technical difficulties, we finally got to hear his favorite (reference) tunes on my system, albeit in a slightly handicapped capacity. At the time, I was unable to rip his CDs to listen through my reference two channel system. The only way for Tony to hear his music was to pop the disc into my Sony Playstation (PS3). Granted, not very high up on the list of high end audio equipment to say the least. But my prized little gaming and Bluray player was enough to pull off enough magic that Tony was sufficiently impressed. His description of the sound quality was "not audiophiley", to the extent that he commissioned me to build him a set of Sterling Duets of his very own.

So here is Tony's build thread....

We chose (my favorite) three layer of 3/4" Russian Baltic Birch with a sand fill. Darrel Hawthorne will be building the XO's and shipping them to me later. I'll be building Tony an enclosure to house the XO unit as well as the Keiga plate amps (one for each speaker).
The new twist to this one, is that Tony has chosen to use a veneer, which is new to me. But fortunately, he's trusting enough of my abilities to see what I can come up with. Not sure what type of wood veneer we'll have, that comes later.

Here's what we've got so far, with a couple captions:

Four sheets of 5'x5'x3/4" Russian Baltic Birch:


Rough cuts for the speakers six layers of plywood and the XO/Amp box:
{Note; if it looks like I cut the end of some of those a bit crooked, that angle happens to be exaclty 12.5 degrees. More on that later.}


A photo of the right and left channel middle layers with the markings that will be hollowed out later to accept the sand fill:


The six layers for the two speakers:


The layers stacked:



Offline Bob in St. Louis

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Re: My build of a pair of HawthorneAudio Sterling Duets
« Reply #1 on: December 05, 2011, 03:34:55 PM »
I've got a bunch of photos from the work today, mainly dealing with the "T-Nuts" and what they are (I've been asked privately what a t-nuts is, and how it works). That being said, the pictures mainly focus on those and what's up with them. There's also noticable progress on the project as a whole though....of course.  ;)

The first pic is a test fit of the two 15" drivers. Of course, now would be a good time to know if they don't fit.
Notice the R1, R2, R3.....The "R" is "Right speaker" and the number is it's position in the layers.
- Number 1 is the face (front) of the speaker.
- Number 2 will be the one that is hollowed out for the sand. Middle.
- Number 3 is the back.



Next up, the t-nuts, their location, how they're pre-drilled and what a t-nut looks like in general.



Here's the t-nut in place, before it's been drawn down into the wood.
In the background are the pieces of wood that will be the front plates that will house the amps and crossovers. This is the piece of wood that will attach to the speaker baffle directly, and hold the two together.
After that, I'll just shut up, stop talking and show a few pictures. They should speak for themselves.










This one needs a few words.....
The heads of the t-nuts are not flush, and in a situation where the t-nut must "disappear" totally, 100% on both sides, you have to give the layer behind it some room.
The easiest way to do that would be to use a paddle bit so the head of the t-nut has a "void" to go into.
That can be done on the piece of wood the t-nut goes into, or the piece of wood that will be meshing with the t-nut, whichever you prefer.
Personally, I like to leave as much material as possible for the t-nut to attach to. If you cut a bunch of wood out to accomidate the t-nut, you've weakend the material. And if you're using expensive material like this, that would be a shame.




Time to blow the saw dust away, get things cleaned up (yes, I actually do vacuum the floor of the workshop before I do this)


In the previous picture, I put layer #2 on top of layer #3, and traced around the openings.......(scroll back up a bit)
These open areas will NOT receive glue during the next step.......(now scroll down)
The zig-zag pencil marks will not get glue.
Also note, that I didn't get too close to the opening of the where the driver will mount to. No glue will (ever) be needed there.


Alright, now we're getting somewhere.
It's glue time, so my priority here was just that, not taking pictures.
Bam


No man has ever died with too many clamps.
Done for the weekend. See you next Saturday. Buh Bye......  ;)

Offline richidoo

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Re: My build of a pair of HawthorneAudio Sterling Duets
« Reply #2 on: December 05, 2011, 04:38:21 PM »
We love our fav shill from St Louis! At least you're shilling something awesome! And your woodworking and photography are awesome too.  (I am a BISL shill.)
This is good timing for me, I've been reading about big high efficiency coax OB speakers. :drool:  But most of the coaxes are European or Asian made. Your Silver Iris drivers are all American. I like that, dirty nationalist that I am.

I'd love to hear these. Gotta check out hawthorne forum for a local owner.
Thanks Bob!!
Rich

Bigfish8

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Re: My build of a pair of HawthorneAudio Sterling Duets
« Reply #3 on: December 05, 2011, 05:57:06 PM »
Bob:

I don't spend much time around here these days but your post about these speakers gathered my interest.  Your work has a master craftsman appearance.  I look forward to reading additional posts of your progress.  I bet they will sound amazing.

Ken

lonewolfny42

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Re: My build of a pair of HawthorneAudio Sterling Duets
« Reply #4 on: December 05, 2011, 11:05:59 PM »
No wonder your wife keeps you around...your a handy guy Bob... :rofl:

Lookin' good so far.... 8)

Offline bpape

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Re: My build of a pair of HawthorneAudio Sterling Duets
« Reply #5 on: December 06, 2011, 06:18:03 AM »
Nice job Bob.  Just amazing that the front will hold up with all of the facing cut out except for that web.

Bryan
I am serious... and don't call me Shirley

Offline rollo

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Re: My build of a pair of HawthorneAudio Sterling Duets
« Reply #6 on: December 06, 2011, 08:41:35 AM »
  Hey Bob. Good stuff, thanks for sharing. Big Fish good to see you here. Miss you guys.
  Admire your skills Bob, really nice work.


charles
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Offline Bob in St. Louis

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Re: My build of a pair of HawthorneAudio Sterling Duets
« Reply #7 on: December 06, 2011, 01:36:40 PM »
Thank you guys for the complements!  :thumb:
Rich, sounds like you should drop by and check out my fellow shills open baffle enthusiast buddy's.
I would think there's somebody in your neck of the woods.

Bryan, the webbing you see is the middle layer of 3/4" plywood. The voids, or cavities will be hidden inside and contain the sand. All that's seen in the last pic is the middle and rear layer.Before the facing goes on, the sand goes in.

Thanks again for the very kind words fellas!
Bob

Offline Bob in St. Louis

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Re: My build of a pair of HawthorneAudio Sterling Duets
« Reply #8 on: December 11, 2011, 05:16:33 PM »
Done for the weekend, it's break time.
A friend and neighbor of mine that also builds speakers gave me a heads-up about a material that he's proven works better than sand to dampen and absorb the vibrations. Since he's running a business building spekaers, he asked that I not tell what the "secret sauce" happens to be. However gave me permission to show the build pictures with the promise that I plug his companys name "Vapor Audio".
Now I have permission to show pictures of the material.  :lol:

One baffle layed down, cavities up, mounds of "special secret material" in them.


Ran a straight edge across to get everything layed flat. I walk around the baffle with a rubber mallet gently tapping the edges to help settle the material, otherwise after time the speakers vibrations would settle the material to the point where there would be open void.


Wood glue has been troweled on


Clamp time




After both baffles have been filled, and sealed up, I put one on top of the other and clamp them both over night. If I had enough clamps, I wouldn't have to do it this way.
The notebook paper in between is a "just in case" some glue gets between the two speakers. That would suck.



And final picture shows the profile after I ran the baffles across the table saw. I did the chamfer on the sides and top, front and back. Not the bottom.
[/

Offline richidoo

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Re: My build of a pair of HawthorneAudio Sterling Duets
« Reply #9 on: December 11, 2011, 09:26:10 PM »
As usual, very fine workmanship. Thanks for the pics Bob!

That secret sand looks like gunpowder....

Nice touch on the chamfered edges.  :thumb:

Offline tmazz

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Re: My build of a pair of HawthorneAudio Sterling Duets
« Reply #10 on: December 11, 2011, 09:41:34 PM »
As usual, very fine workmanship. Thanks for the pics Bob!


+1

That secret sand looks like gunpowder....

Wow, that would give it a hell of a transient response!  :shock:
Remember, it's all about the music........

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Offline Bob in St. Louis

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Re: My build of a pair of HawthorneAudio Sterling Duets
« Reply #11 on: December 12, 2011, 05:20:26 AM »
I was going for a speaker with more "impact". They say Open Baffle doesn't have enough of that, so I thought the gunpowder was a good idea.
I'll let you know how it turns out.

Bob

Offline JLM

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Re: My build of a pair of HawthorneAudio Sterling Duets
« Reply #12 on: December 12, 2011, 07:59:56 AM »
Adding mass is a great idea for O.B. (or installing struts to anchor them to the room structure, but that wouldn't be too domestically acceptable, eh?).

Offline rollo

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Re: My build of a pair of HawthorneAudio Sterling Duets
« Reply #13 on: December 12, 2011, 08:11:52 AM »
Bob I hope they don't short. Kidding aside gunpowder ?? Who would have thunk.
    I'm a fan of Bees Wax. Heat it up pour it in let it set. Is it more affective who really knows. Secret sauce is a better name so it must work better. :rofl: :rofl:
   The concept of treating in between the baffle is a great idea. You may consider using visco elastic rings in between the driver and baffle for even more vibration control.
  Looking good keep the photos coming.


charles
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Offline Bob in St. Louis

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Re: My build of a pair of HawthorneAudio Sterling Duets
« Reply #14 on: December 12, 2011, 09:47:28 AM »
Thanks guys!  :thumb:

Charles, "No", it's not gunpowder, I can say that much.  :lol:
But yea, loading the innards with a loose materials helps quite a bit.

I should have some more pictures next weekend when I get back in the shop.

Bob