Natalie P Project (First speaker build!)

[Whrswoldo]

After months of snooping around this forum as well as a few others and researching a set of speakers to build I have settled on a set of Natalie P floorstanders as layed out in the mission accomplished thread on this forum. This is my first speaker build and first serious attempt at carpentry :T (with the exception of a sealed subwoofer box for my car)

They will be ~60L gross and ported to 28hz as recommended in the Nat P thread. I will be making them out of 3/4" birch ply and finish will either be some sort of red or other dark stain or a black textured paint coat (possibly truck bed liner, not decided yet ) They will eventually be powered with a crown xls 402 pro amplifier

I have started cutting the needed pieces although I have managed to run out of wood I have the front baffles, sides, backs, braces, tops and bottoms cut although I intend to make a double-thick front baffle and there is not enough wood left, so I will need to swing by home depot tomorrow and get a small sheet of wood. I never bothered adding up the area of this thing and I just assumed 1 4'x8' sheet would be enough, oops ops:

My not so interesting pile of wood:



Also, I am cutting these things with a circular saw and the saw blade I bought is already dull. The last several cuts were very slow and smelled like wood burning. 8O I suppose I will pick up another one of those as well (It was a cheap $5 steel blade as I could not find any carbide blades with the number of teeth needed for cutting plywood) As if that wasn't ghetto enough I am doing my cutting on a plastic table on my back porch :rofl: (I currently live in an apartment/townhouse with no garage) The edges are kind of sad although they will be rounded over anyways with a router and so it should not matter too much.

Will wood glue alone be fine for holding these together? I have contemplated using dowels or finishing nails although I have not noticed anyone else using such things in their designs and so I am not sure if it is even necessary. If anyone has any advice I am all ears, and I'm sure I will be asking for help down the road. I am trying to document everything as I go along so hopefully this will be interesting to someone.

[kingpin]

If your joints fit tight then all you need is wood glue and clamps.
If you have gaps or ill-fitting joints construction adhesive(loctite water-based construction adhesive)works awesome and helps to fill in gaps and bad joints.

[Whrswoldo]

If your joints fit tight then all you need is wood glue and clamps.
If you have gaps or ill-fitting joints construction adhesive(loctite water-based construction adhesive)works awesome and helps to fill in gaps and bad joints.

This is what I assumed although with my super accurate cutting skills your advice may come in very handy :T

If it worked for your massive speakers (very impressive build by the way) then I have no doubt it will work for mine.

[Mazeroth]

Be sure to use some sort of wood conditioner before apply stain to that birch. Birch is tricky to stain and loves to get splotchy. I've found that a gel-based stain (I think the kind I have is Olympic) works much better than an oil-based stain on birch. Definately practice staining on some scrap pieces before your final application.

[PoorboyMike]

Be sure to use some sort of wood conditioner before apply stain to that birch. Birch is tricky to stain and loves to get splotchy. I've found that a gel-based stain (I think the kind I have is Olympic) works much better than an oil-based stain on birch. Definately practice staining on some scrap pieces before your final application.

Danish oil works very good on birch too, but color selection is limited.

[herm]

Since you have a router - why not try the flush-trim bit method of box
construction?

When you assemble the box, move both sides in by 1/4 inch or so. Let
the top, bottom, front and back hang over by a little. Then trim them
with the router.

Like magic, a perfect fit!

herm

[CraigJ]

Will wood glue alone be fine for holding these together? I have contemplated using dowels or finishing nails although I have not noticed anyone else using such things in their designs and so I am not sure if it is even necessary. If anyone has any advice I am all ears, and I'm sure I will be asking for help down the road. I am trying to document everything as I go along so hopefully this will be interesting to someone.

I use a biscuit jointer and biscuits when I build a box. The main advantage of the biscuits is they help align the "less than flat" pieces when I glue the pieces together. Harbor Freight has a "cheap" one if you don't plan on using it a lot. Screws and/or nails can also be used, but I believe they require more work to conceal, especially when staining.

Good luck and have fun.

Craig

[PoorboyMike]

I use a biscuit jointer and biscuits when I build a box. The main advantage of the biscuits is they help align the "less than flat" pieces when I glue the pieces together. Harbor Freight has a "cheap" one if you don't plan on using it a lot. Screws and/or nails can also be used, but I believe they require more work to conceal, especially when staining.

Good luck and have fun.

Craig

He could also get a bit for his router to do biscuits.

[Whrswoldo]

Thanks for the replies guys!

Since you have a router - why not try the flush-trim bit method of box
construction?

When you assemble the box, move both sides in by 1/4 inch or so. Let
the top, bottom, front and back hang over by a little. Then trim them
with the router.

Like magic, a perfect fit!

herm

Yeah this was the plan for the front baffle, top, bottom and sides. I picked up a 1" flush trim bit from woodcraft the other day for that very purpose :T

Be sure to use some sort of wood conditioner before apply stain to that birch. Birch is tricky to stain and loves to get splotchy. I've found that a gel-based stain (I think the kind I have is Olympic) works much better than an oil-based stain on birch. Definately practice staining on some scrap pieces before your final application.

Thanks for the advice, I didn't realize there could be a difference between gel and oil based. I have thought about applying a clear shellac or sand sealer and then a mahogany colored stain. I'm not sure about the sealer, I have heard a few different ideas before (PolyU? Tung oil?) although even after some research I'm not really sure about the difference. I mainly am looking for something that will protect against moisture (such as some asshat leaving a cold drink on my speaker :M ) and not be too difficult for a novice to apply.

I haven't been able to get much work done today due to rainy weather, although I did manage to pick up some more supplies from HD. Unfortunately, they were out of the precut 2'x4' sheets of 3/4" birch ply and rather than buy a whole sheet and cut it into pieces i bought a 2'x4' sheet of 3/4" mdf instead, as this wood will be entirely internal (inner baffle and bracing.) With luck the weather will clear up soon.

[---k---]

With my last three projects using Birch Ply, I've applied Minwax Wood conditioner first, then Minwax Oil Stain, then a Tung Oil Finish (4 coats). I've been happy with the results, and have received high WAF.

I've tested a few peices and undersides without the Minwax Wood Conditioner, and for the most part it was fine, but there was a spot here or there that just sucked up the stain and had a flatter finish. So, I would definitely recommend the Wood Conditioner first.

As for Tung Oil, Danish Oil or whatever ever. Polyurethane is going to be the most durable finish and will allow someone to place a cold drink on your speaker without you having to kill them. But, it is also a bit trickier and can (if not painstakingly done) look like the speaker is dipped in a cheap plastic. It is also shiny, and in my HT room I don't want shiny. I'm not a fan of poly (read: I'm not patient enough to do multiple thin coats to make it look good).

Tung oil will give the wood a nice, deep rich look with a satin like finish. If you watch WoodWorks on DIYNet on every episode for every project David Marks says, "And now to apply my favoirite finish, Tung Oil!" Danish Oil is similar. The downside is that any oil doesn't have the waterproofing abilities of poly.

Luckily, a can of Tung Oil and Poly is fairly cheap, and you can experiment. Combinations are also possible. Finishing your speakers often takes as much or more time then building the boxes. I find it a necessary evil, while some here find it enjoyable to make amazing looking speakers.

[cameronthorne]

Ryan,

I'm about to build some small subwoofers hidden in plant stands and an end-table. I was going to go with no stain, tung oil, and a polyurethane finish, but my wife wants to go with a medium tone, which I think means stain. I was under the impression you used stain or oil, not both, but apparently I am mistaken. (I have never done any woodworking before.)

The material is all Russian birch ply. I definitely want polyurethane on the top coat for the waterproofing. What other things should I consider to get a medium tone while still showing the grain of the wood nicely? Stain? Oil? Both?

Do you have any pictures of your last project?

Thanks.

-- Cameron

[ThomasW]

If you're going to top-coat with poly you'd use a stain, not an oil.

[cameronthorne]

So the best bet for baltic birch ply is ?: prep the wood with a conditioner, apply an oil-based stain to the desired darkness (gelled oil might be easier to apply), and finish coat it with either a curing oil or oil-based polyurethane, depending on whether you need water-proofing or not? Curing oils like boiled linseed oil or tung oil seem to be popular.

I think my end table sub needs poly, because it will have drinks on it. But I don't want a thick layer built up on top. Will the wipe-on polys go on thin enough that they will give a good look without giving up protection?

[Dennis H]

Oil finish tips. These are from the Watco page but other oil finishes are similar. I find the colored Watcos to be easier to use than most stains, even if I want to add lacquer or poly finish coats. No 'exotic' colors but I'm usually going for some shade of brown anyway. As always, experiment on some scrap before trying it on your speakers.

http://www.rustoleum.com/product.asp?frm_product_id=112&SBL=1

Some open grained woods, such as oak, can “bleed” excess oil finish from their pores until the oil has cured. Should this occur, wipe the surface occasionally until the bleeding stops. If the spots of oil are left to dry on the surface, burnish off with synthetic steel wool.

Certain woods such as pine, fir, birch, maple, or spruce may have a tendency to take color unevenly. To help solve this problem, place a small amount of Danish Oil Finish “Natural” on a cloth and wipe lightly on wood. Wipe dry before applying stain color.

A surface coat is not necessary over WATCO wood finishes, however if a clear finish is desired, use Varathane Professional or Interior Diamond Wood Finish. These products may be applied 72 hours after applying a WATCO wood finish or Rejuvenating Oil.

[---k---]

Yeah, I got pictures. Which project were you looking for? Sub, tv stand, or gear rack?

I agree with Thomas that if you're going to poly, no oil needed. I'm not an expert in finishing (or really anything), so I recommend going to the library and picking up a good book on finishing. they should have several. The ones by Fine Woodworking or Taton Press are always good.

The only other tip I can give you is that the amount of sanding you do will have a big effect on how dark the stain gets. If your last sanding is with a 150 - 180 grit, you'll get a lot deeper color than if you work you're way up to 320 grit. I saw in a magazine recently a suggestion to sand edges with higher grit sandpaper to prevent the edges from soaking up the stain. Wish I would have read that earlier. So practice on scrap is best.

[Whrswoldo]

Wow it's been over a month since my last post :E Summer school sucks (especially when you are taking 10 hours so that you can graduate already) and the weather here has been terrible, which puts a damper on things when you don't have a garage. Did I mention it is expected to rain here through mid July? This is Texas, it is summer, we are supposed to be having a drought. A few updates:

I have finished cutting all of the wood! Well, the straight cuts anyways I am currently waiting for the delivery of a jasper jig (model 200J) unfortunately my local Woodcraft only carried the simplified 270J which will not cut holes smaller than 7". After I cut out the speaker holes on the baffle and for the port i'll be ready to start gluing.

Question: The inside of the enclosure is 12" deep and the port will be 11" long, part of which will be embedded in the rear wall of the enclosure. Will 1" to 1.5" be enough clearance between the front baffle and the port?

[Denton]

Question: The inside of the enclosure is 12" deep and the port will be 11" long, part of which will be embedded in the rear wall of the enclosure. Will 1" to 1.5" be enough clearance between the front baffle and the port?

I've been told that the space between the end of the port and the enclosure wall should be equal to or greater than the diameter of the port. Hopefully Jon Marsh or another experienced builder can comment.

[Whrswoldo]

I've been told that the space between the end of the port and the enclosure wall should be equal to or greater than the diameter of the port. Hopefully Jon Marsh or another experienced builder can comment.

Hmm this could be unfortunate, my backup plan was to bottom-mount the port, in which case the clearance would be approximately the length of the speaker spikes. I guess I'll just try and see how it turns out.

On another note, how does one usually go about routing the cutouts for the speakers when the baffle is double-layered? I am using 2 3/4" layers for 1.5" total. Do people usually cut these pieces separately and then glue them together or glue together and cut together? Assuming they are glued together and cut at the same time, are multiple passes at increasing depths done? As you may have noticed I am not exactly Norm Abrams, any advice is appreciated. :B

[---k---]

The more room for the port to breath, the better. I think 1/2 the diameter is minimum.

Yep, glued together and then multiple passes at increasing depth. You may have to flip it over and finish from the backside depending on your bit. Thomas has a page on his website with step by step photos of one way to do it (but I've always done it differently with just a upcut bit at decreasingly smaller radii).

[Whrswoldo]

Update! I have received the speakers/xover parts from PE along with a hole routing jig and so I can finally get into the meat of the project. I have decided to just go with a 10" long port which with my ~55l box should work out to a 28hz tune.

I plan to embed a short section (~3/8") of the pvc within the rear wall of the enclosure and then round-over the opening on the back. Is there any inherent problem with this idea?



I'm going with a behringer cheapo amp (a500) for power, and hopefully I will be firing these up by next weekend.

[PoorboyMike]

A roundover should work fine for the port opening, unless you are using really small PVC. What size do you have?

[JonMarsh]

Update! I have received the speakers/xover parts from PE along with a hole routing jig and so I can finally get into the meat of the project. I have decided to just go with a 10" long port which with my ~55l box should work out to a 28hz tune.

I plan to embed a short section (~3/8") of the pvc within the rear wall of the enclosure and then round-over the opening on the back. Is there any inherent problem with this idea?



I'm going with a behringer cheapo amp (a500) for power, and hopefully I will be firing these up by next weekend.

It will work, but it's not really a "flared" port- compare it to the construction of a 2" Precision Port, where the flare radius is about 2". It means you might get some port chuffing at a bit lower SPL level. I haven't tested a configuration like what you're describing; we could get an idea in Unibox of the affect by modeling it as an unflared port.

[PoorboyMike]

It will work, but it's not really a "flared" port- compare it to the construction of a 2" Precision Port, where the flare radius is about 2". It means you might get some port chuffing at a bit lower SPL level. I haven't tested a configuration like what you're describing; we could get an idea in Unibox of the affect by modeling it as an unflared port.

I'm just guessing, but he said he needed an 11" port in the 60L cabinet, so it must be at least 3" PVC? (I don't have unibox here at work)

[Whrswoldo]

I am using a 3" diameter port, 10" long, and with my 55l net enclosure I expect to have a ~28hz tune.

Freq response according to winisd:



Here's the port velocity:

[jliedeka]

I use a biscuit jointer and biscuits when I build a box. The main advantage of the biscuits is they help align the "less than flat" pieces when I glue the pieces together. Harbor Freight has a "cheap" one if you don't plan on using it a lot. Screws and/or nails can also be used, but I believe they require more work to conceal, especially when staining.

Good luck and have fun.

Craig

I'm planning to use a biscuit joiner for cabinet assembly. I was wondering which plates to use. Are #20s too big to use in 3/4" MDF? I can also work with #10 and #0.

Jim