Plans for Metronome

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Guy 13

Re: Plans for Metronome
« Reply #20 on: 5 Jun 2013, 02:40 am »
Thanks Guy,

I went out to the wood stack tonight to look for some Sycamore.  I found some, but it wasn't the Spalted.  It is interesting wood.  I cut some real nice Spalted Sycamore this year, but it'll take a year or so to dry.

I'll definitely take some pictures of the build.  Right now my wife and I are finishing up a rebuild of a 1952 classic wooden cruising boat.  It'll go in the water on June 21.  So, we're pretty busy with that.  We're going to circumnavigate Lake Michigan and that will take most of the summer.  I'd like to have the enclosure and driver picked, along with the wood put up in the shop before we go so I can start right in when we get back.

John
Hi John and all Audio Circle members.
Do you rebuilt/repair boats for a living?
Maybe you should show us what you can do or what you did.
Just a suggestion.

Guy 13

Johnaki

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Re: Plans for Metronome
« Reply #21 on: 5 Jun 2013, 10:47 am »
Hi John and all Audio Circle members.
Do you rebuilt/repair boats for a living?
Maybe you should show us what you can do or what you did.
Just a suggestion.

Guy 13

Don't have the talent to rebuild old boats for a living.  I fully retired this year and have always wanted to have a wooden cruising boat.  I bought an abandoned 1952 Herreshoff H-28 and stripped the interior out (wasn't much left in it) and have been working this year to get it in cruising shape.  It's nothing special, just a lot of hard (and cold this winter in Northern Michigan) work.  In a few weeks I should be able to put some before and after pictures up.



I am learning a lot of joinery skills that should serve me well when I start the Metronome build.  I've also built a pram/dinghy for my first sailboat.  So, I've got some background in working with odd angles and compound curves.

John

Guy 13

Re: Plans for Metronome
« Reply #22 on: 5 Jun 2013, 12:05 pm »
Hi John and all Audio Circle members.
Nice boat.
If you are retired, you will have plenty of time sailing,
unless you spend all your time on building the metronome.
Please keep us informed on the audio end results of your metronome.
Don't forget to post pictures, I love pictures.
Taking about pictures, how about pictures of the inside of your sailboat.
I know I am pushing my luck.
Well, that's why I was born on a Friday 13th.

Guy 13

jeffh

Re: Plans for Metronome
« Reply #23 on: 5 Jun 2013, 11:47 pm »
John,
That's going to be a nice boat when you finish.  :thumb:

FullRangeMan

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Re: Plans for Metronome
« Reply #24 on: 5 Jun 2013, 11:58 pm »
This Metronome is a horn?? How much gain it provide or has no gain??

Johnaki

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Re: Plans for Metronome
« Reply #25 on: 6 Jun 2013, 01:14 am »
Here is the inside of the boat -- still unfinished. 



I'm trying to come up with a way to get some speakers on the new bulkheads.  The lights are brass, most of the hardware is bronze and you can see the yet uninstalled brass sink in the foreground.  I would hate to put in plastic marine speakers on those nice marine mahogany ply bulkheads.  Anybody got an idea for a small full range speaker.  The cabin is 8' x 8' with 5' headroom.

Jeffh, your computer speakers in your system look about the right size.  Can you tell me about them?

John

jeffh

Re: Plans for Metronome
« Reply #26 on: 6 Jun 2013, 03:29 am »

Jeffh, your computer speakers in your system look about the right size.  Can you tell me about them?

John

They were built using the Fountek FR88EX 3" Full Range. I bought them from Madisound.  On my desktop they sound great and have a great soundstage.  I am using a sub, which I think you would need with these speakers.

Johnaki

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Re: Plans for Metronome
« Reply #27 on: 6 Jun 2013, 06:54 am »
They were built using the Fountek FR88EX 3" Full Range. I bought them from Madisound.  On my desktop they sound great and have a great soundstage.  I am using a sub, which I think you would need with these speakers.

Thanks Jeff,

Could you tell me the approximate size of the enclosures and the sub?

John

jeffh

Re: Plans for Metronome
« Reply #28 on: 6 Jun 2013, 01:30 pm »
Outside they are 10.5 x 15.5 x 25.5 cm

Here is my build thread:   http://www.diyaudio.com/forums/full-range/188569-fountek-fr88ex-3-build.html

Plans can be found here: http://www.diyaudio.com/forums/full-range/175056-martello-enclosure-fr88ex.html#post2327342

The sub is a Sunfire I bought used a few years ago.  Overkill for a desktop system, but is sounds great with these two little speakers. :D

jparkhur


Raiderone

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Re: Plans for Metronome
« Reply #30 on: 7 Jun 2013, 09:32 pm »
The Metronome looks deceptively simple to build, yet I see some angles at the joints (top/bottom plates) that are not in any of the plans.  Even the dims on the more detailed plans don't account for tilt; i.e., if you cut the board to the dims and then tilt it wouldn't the overall height decrease?.  However, to an experienced woodworker the angle joints may just be self explanatory or perhaps just cut the board and the measure the angle.

I don't know the math to calculate the angles based on the dimensions given on the plan.  So, if anybody can help I'd really appreciate it.

Johnaki

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Re: Plans for Metronome
« Reply #31 on: 7 Jun 2013, 11:31 pm »
The Metronome looks deceptively simple to build, yet I see some angles at the joints (top/bottom plates) that are not in any of the plans.  Even the dims on the more detailed plans don't account for tilt; i.e., if you cut the board to the dims and then tilt it wouldn't the overall height decrease?.  However, to an experienced woodworker the angle joints may just be self explanatory or perhaps just cut the board and the measure the angle.

I don't know the math to calculate the angles based on the dimensions given on the plan.  So, if anybody can help I'd really appreciate it.

Right now, I'm looking at the plans for the with Fostex FE127e.  There is a piece at the top that is made of 18mm ply that closes the opening at the top.  This side of the piece is 49.4mm wide on top of the peice and 50.8mm wide on the bottom.  That's a 1.4mm difference.  Make a mark 1.4mm on the top edge.  Turn the piece over and tilt your bandsaw table so it matches the line you just drew.  Set the bandsaw fence so the blade barely touches the bottom of the piece (which is now on top because you've turn it upside down.). Run the piece through the bandsaw and you'll cut 1.4mm more off the top (which is now on the bottom) than the bottom.  The fit should, theoretically be perfect.  However, I usually have to do a little touch up with a plane or disc sander.

Hope that helps.  It's hard to explain in words, but if you can get someone to show you, it's pretty straight forward.  It can be done on a table saw also, and, it's such a small angle, it would be pretty easy to do the entire process with a disc sander.

John

planet10

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Re: Plans for Metronome
« Reply #32 on: 8 Jun 2013, 01:45 am »
This side of the piece is 49.4mm wide on top of the peice and 50.8mm wide on the bottom.  That's a 1.4mm difference.  Make a mark 1.4mm on the top edge.

Wouldn't you want half that on each side?

dave

Johnaki

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Re: Plans for Metronome
« Reply #33 on: 8 Jun 2013, 06:34 am »
Wouldn't you want half that on each side?

dave

Yup!  Good catch Dave.  Of course, that's why my practice piece would've come out wrong and it would take me more than one try to get the job done.

That also means the cut would be so small that you would be able to sand it easily.

John

JCS

Re: Plans for Metronome
« Reply #34 on: 8 Jun 2013, 03:15 pm »
This is why it's a good idea to make a drawing.  I use the drawing to measure the angles, then I cut the top & bottom pieces as best I can on the table saw or miter saw.  Of course, small touch ups with a sanding block are always needed to get a perfect fit.

Cheers,  Jim

Raiderone

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Re: Plans for Metronome
« Reply #35 on: 8 Jun 2013, 10:02 pm »
Actually, the 127e plans do have the angle joints listed, kudos to the plan drafter.  I ran the front panel through this: http://keisan.casio.com/exec/system/1223014436 and came up with 2.68xx, so it is accurate as far as I can tell.  It has been over 30 years since high school trig so I had forgotten how to find the angle of the hypotenuse.  Now, this leaves us with how accurately we can cut and glue up the panels/plates.  Any tips/tutorial would be greatly appreciated.  Thanks.

Johnaki

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Re: Plans for Metronome
« Reply #36 on: 8 Jun 2013, 10:36 pm »
Actually, the 127e plans do have the angle joints listed, kudos to the plan drafter.  I ran the front panel through this: http://keisan.casio.com/exec/system/1223014436 and came up with 2.68xx, so it is accurate as far as I can tell.  It has been over 30 years since high school trig so I had forgotten how to find the angle of the hypotenuse.  Now, this leaves us with how accurately we can cut and glue up the panels/plates.  Any tips/tutorial would be greatly appreciated.  Thanks.

Ah! Your right, they're right there in the middle of the page.  I hadn't noticed them before.  Thanks for eyesight!  Now, if we could still buy 127's I'd be all set :cry:

John

Raiderone

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Re: Plans for Metronome
« Reply #37 on: 9 Jun 2013, 08:57 pm »
I've got 4 pair of the 127e, unfortunately they are unlistenable without at least 3db bsc.  Kinda defeats the purpose of the simplicity and directness of a single full range driver.  I've been messing with the 103en, 105wk, and Alpair 7.3 and all of them sound really good within their respective bandwidth; much better than the 127e.  Having said that, if I had to pick one driver it would be the 165wk.  The smaller drivers excel at imaging/soundstage, but don't have enough down low to be satisfying in the long run.  Conversely, the larger drivers 8" or larger do the opposite well.  The 6.5" is the compromise.  Perhaps, a doubled up 125wk would work too, (if needed with one rolled off with a coil).  And if your amp can take it, parallel them to double the output.  The literature that comes with the Fostex wk series has recommendations that are fun to look at.