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-   -   1st timer building Fonken Floorstander MkII with Planet 10 FE127eN drivers (http://www.diyaudio.com/forums/full-range/114088-1st-timer-building-fonken-floorstander-mkii-planet-10-fe127en-drivers.html)

rbclark 22nd December 2007 12:37 PM

1st timer building Fonken Floorstander MkII with Planet 10 FE127eN drivers
 
Thus far I've zero experience building speakers. I stumbled into diyAudio when I was looking for a way to retrofit some old speakers with bad drivers. With help from the forum, I replaced 2 woofers & a tweeter with a single FE167, sealed up the cabinet well and after some breakin they sound really good. http://www.diyaudio.com/forums/showt...hreadid=107127

For my first project, I've selected what I think will be one of the easiest builds - Fonken Floorstander Mark II, is not very big, and that takes advantage of the Planet 10 FE127eN. Can't wait to hear what an EnABL'd speaker sounds like. I'm building these out of 5/8 inch MDF. I wanted Baltic Birch, but I had trouble finding it so I figure I'll *try* MDF. I bought it pre-cut at a cabinet maker and the cut pieces are perfect! *Much* better job than I could have done with my circular saw. I'm hoping that this is just my 1st of many projects and that my skills will eventually improve to the point where I can build (& finish) some of the more complex designs.

I've collected all the parts and now I'm trying to get started and I need some construction advice.

1) - Holes - I should have had the cabinet maker drill the holes for me because that's my 1st problem. I bought a 4 inch hole saw (http://www.homedepot.com/webapp/wcs/...ctId=100495363) for the drivers - haven't tried it yet. But I started with the holes for the holey brace and can't get through the MDF! I've tried a 2 inch hole saw (like this: http://power-tools.hardwarestore.com...ELAID=42563461) with an old 9 inch drill press, a battery drill and an electric drill (a very old one). So the 1st question is: what does it take to drill large holes in MDF? Could it be the hole saw I'm using?

2) - Holey Brace Holes Percentage - The Fonken floorstander MKII plans don't say how many holes to drill or how big they should be or what percentage of the total board area they should be. Elsewhere on the forum and Planet 10 plans, I've seen that 35-40% of the area should be holes and at least once in the forum a recommendation for 50%. Is there a way to determine what this number should be? I don't know how important it is. Maybe the range is wider 35-50%? Or should I just drill a buncha holes and move on?

3) - Lining/Stuffing I bought some adhesive backed acoustic foam from Parts Express for the liner because I figured it would be easy to use but, browsing the forum, I get the idea that's not the best way to go. I don't think it could be used on the holey brace because it would seal the holes. Can anyone give me a link where I can order some recommended material for lining? I'll be using the stuffing that came out of my old speakers (sounded so good without, I've never tried putting any back in!). Looks like it meets the description of what's recommended.

Thanks for the help!
Bob

gmilitano 22nd December 2007 02:10 PM

Re: 1st timer building Fonken Floorstander MkII with Planet 10 FE127eN drivers
 
Quote:

Originally posted by rbclark
Thus far I've zero experience building speakers. I stumbled into diyAudio when I was looking for a way to retrofit some old speakers with bad drivers. With help from the forum, I replaced 2 woofers & a tweeter with a single FE167, sealed up the cabinet well and after some breakin they sound really good. http://www.diyaudio.com/forums/showt...hreadid=107127

So you're not really a first timer! :)

Quote:

Originally posted by rbclark

For my first project, I've selected what I think will be one of the easiest builds - Fonken Floorstander Mark II, is not very big, and that takes advantage of the Planet 10 FE127eN. Can't wait to hear what an EnABL'd speaker sounds like. I'm building these out of 5/8 inch MDF. I wanted Baltic Birch, but I had trouble finding it so I figure

An open baffle would be easier! :D Sometimes it is called multi-ply birch instead of baltic birch.


Quote:

Originally posted by rbclark

very old one). So the 1st question is: what does it take to drill large holes in MDF? Could it be the hole saw I'm using?

I use the hole saws and they work very well. You don't want to apply much down pressure. Especially when you are almost through or you might break off a chunk of MDF. My cordless drill does not have enough power to even come close. I have done 3/4" MDF with a good 3/8" drill. Obviously a 1/2" works even better.

Hope this helps.

EEatKSU 22nd December 2007 02:25 PM

Using a hole saw in you have to continually back the saw out enough to clear the sawdust from the teeth (while still keeping the pilot drill bit in) since there is no way to clear the sawdust out. So just take a little bit longer and back out after a little bit each time and you'll get it figured out.

vinylkid58 22nd December 2007 06:09 PM

1) I used my trusty old jigsaw for the driver brace.

2) 50% holes is a good target.

3) I didn't bother lining the brace. I used recycled felt from an old pair of Sansui's for the interior. The acoustic foam should be fine.

Jeff

loninappleton 22nd December 2007 06:25 PM

I've been using hole saws for all my projects and thye have lasted for years.

With your suped up FE127e's the hole saws are a good investment for many builds to come.

After fiddling with hole saws to get a smooth cut all the way through,
someone finally suggested the obvious and right solution: flip the piece over and finish the hole on the opposite side. This prevents tear out and makes the plug easier to get out of the saw.

For larger drivers there are router add-ons that make the job a snap.

Routers and their jigs run into real dough. An acceptable hole can be done with a jig saw and one of it's circle makers.

I've added the chamfer on the interior side of the hole to give some breathing room for the back wave. Chamfering can be done by hand with a file or a router. You get more precision with a file but I have not used that method. Precision and control of a hand file are two different things.

My drivers are the plain vanilla FE127e used in a variety of builds.

rbclark 22nd December 2007 06:44 PM

Thanks for the suggestions. I slowed way down and brought the saw up more often and that helped alot. I was actually able to drill complete holes - but it was still slow. I went back to home depot and bought a Rigid hole saw. It works 10X better than the Black & Decker.

I've got the driver holes cut. They're not exactly centered. I meant for them to be, but... Anyway, this is my 1st set & it's a blast so far.

Now I'm doing the holey braces.

loninappleton 22nd December 2007 06:56 PM

On any square piece, find the center by drawing diagonals at the corners. Where the diagonals meet is the center. Test this by measuring out out to the edge on both sides.

A little wobble can throw off the pinpoint center.

Diagonal measurement is also a test for square.


I've always wanted to have a machinist recut the pilot drill to a brad point but have not found a shop to do it.

vinylkid58 22nd December 2007 07:17 PM

Quote:

[i]Originally posted by loninappletoi]
I've always wanted to have a machinist recut the pilot drill to a brad point but have not found a shop to do it.
Custom grinding & sharpening is usually done at a specialty shop. Ask some of the larger shops where they send their tooling.

Jeff

planet10 22nd December 2007 09:12 PM

Quote:

Originally posted by vinylkid58
2) 50% holes is a good target.
It is somewhat dependent on the airflow in the box. somewhere between 25-45% is sufficient.

The hardest part of these builds is often the holey brace, so i keep trying to figure ways of making them less effort. The goal is to stiffen the box, not impede the air pressures, yet confuse any standing waves.

dave

vinylkid58 23rd December 2007 02:18 AM

Quote:

Originally posted by planet10
The hardest part of these builds is often the holey brace, so i keep trying to figure ways of making them less effort. The goal is to stiffen the box, not impede the air pressures, yet confuse any standing waves.

I think it would still easier to do it your way versus using several wooden dowels (or something else) in the foorstander version.

I had no trouble with the brace in my Fonkens, I put the felt on the panels before glue-up, and then just slid the brace in.

Jeff


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