My NatP project thread, lots of n00bie questions

[syzygylock]

Hi all, I am building a set of NatP and want to know what kind of mount that I can buy off the shelf. I looked at PE but most of the stands seems to have small base, where it doesn't fit the NatP's dimension. Or can you just lay it on the stand even the speaker base is bigger than the stand?

Thanks,

[PoorboyMike]

I'm using a pair of THESE with my NatPs and they work fine. There are little spikes that screw up through the base that help keep the speakers stable.

That said, next time I will make a pair before I spend over $100 on stands. Then you can make them any size you want. :T

[---k---]

This is Mission Accomplished, you're supposed to build you're own stands.

Seriously, there are LOTS of people who have built their own stands in various shapes and styles. The easiest I've seen uses a large diameter PVC pipe with a threaded rod down the middle clamping a top and bottom cap. Pictures of various DIY stands pop up from time to time.

If you're not feeling it, we'll won't judge you for buying stands. I once owned a pair of Premier stands (Paradigm brand). The base was about a 1" on all sides smaller than the speaker, and it worked well. But they were a bit small for a pair of Modula MT's that JonW brought over. It was just a feel thing. Those that Mike linked to look nice.

[syzygylock]

Hahaha, you got me there. Don't make me any more shameful than I really am. I just don't have a lot of wood working experience yet so these stand will help me a bit

Thanks though.

[syzygylock]

DIY misc accessories to get

Hi all, I have an order for 3 NatP mains and 2 Encores surround coming. Then I forgot about the acousta stuffs and the bindings. Is there any other misc accessories that I could've forget? I don't want to pay for $10 shipping for an item that cost $5.

What do you call those nice clips on the XO boards that has the screws and connects the wires together?

Thanks,

[PoorboyMike]

What do you call those nice clips on the XO boards that has the screws and connects the wires together?

Thanks,

Those can be found at your local Radio Shack.

Other things to get in no particular order:

1. Screws for the drivers. I'd get some #6 and #8, 3/4" long. PE sells them in 100ct bags for a reasonable price.

2. Gasket tape. The 3/8" stuff from PE is what I use for the smaller drivers.

3. Do you have solder and hook up wire?

4. Quick disconects for wiring the drivers. PE sells a nice little kit with several different sizes.

I'm sure there is more but that's all I can think of for now.

[JonP]

Ports? The Precision Ports are well made, and have a very pro look. PE has a range of simpler stuff.

I agree, the "speaker quality" foam gasket tape that PE sells is very good stuff, much sturdier foam and better adhesive than anything you'd find at a hardware store. The black oxide screws are nice, and hard to find elsewhere. Maybe get some #4 for the tweeter, depends on the screw head/hole size.

Terminal cup, or individual banana jack plugs to connect to the cables.

Speaker cable wire... which can double as internal wiring. Enough for all of them and the internals. You just missed a sale price on some at PE, but I think it showed in the flyer, so it could be extended another month. Ask if they'll honor the discount...

Probably a few more things we haven't thought of...

[syzygylock]

Ports - check
Gasket - I got 50', is that enough for 3 NatP + 2 Encores MT?
Banana Jack plugs - check
Speaker Wire - check
Solder tools - check
Screws - I got #6, is there any other # to get?

I got the bare banana plugs, can I just use that or do I need to get the filtered terminal cup?

What's a quick disconnect?

Thanks,

[DancesWithBeers]

What's a quick disconnect?

Thanks,

http://www.madisound.com/catalog/index.php?cPath=404_168

[PoorboyMike]

http://www.madisound.com/catalog/ind...?cPath=404_168

What he says.

I bought THIS kit from PE and it has most of the common sizes for speaker terminals. I haven't found a speaker yet where one of them didn't fit.

50' is more than enough.

Also, I think the RS180 can use a #8 screw. Seems like the #6 are a little small.

You wont need a terminal cup if you are getting binding posts.

[Dennis H]

I like the Madisound terminals better than the PE kit although they cost more. The terminals are bare metal so you can solder them in addition to crimping them. The insulation slips on after you solder and it's color coded, black and red.

[syzygylock]

How to cut a baffle hole so that the speaker can sit recessed?

You just use the plunge router and a circle jig to make it right?

[Txgrizzly]

yes, the way i did it was make the shallow depth cuts to the outside diameter of your driver and then step it in going to the same depth (the thickness of your drivers lip) and then cut the hole out (diameter of your driver motor) once you have the dado completed. but i am a newbee at this and some of the old hands might have a better way of doing it.

[ThomasW]

As I posted 2 days ago at the end of the main NatP thread....Use a flat bottom bit (3/4" diameter is nice ) to cut the recess. It should be the outside diameter of the driver and the depth you want. Then do the driver cutout.

I show a slightly different version of the process for recessing (actually called rebasing) a driver for tube sub end plates, here

http://home.comcast.net/~audio-worx/page88Tube-Zilla1.html

[PoorboyMike]

As I posted 2 days ago at the end of the main NatP thread....Use a flat bottom bit (3/4" diameter is nice ) to cut the recess. It should be the outside diameter of the driver and the depth you want. Then do the driver cutout.

Sure that works great, but if a person only has a 1/4" upcut bit (like me :P ) the process that TXgrizly described works good also. :T

[syzygylock]

Thank you very much. I will update this thread some more when the parts come in (should be today)

[wkhanna]

Coming up with a design for stands for my NatP's was the most frustrating part of the entire build. Here are a few of the iterations I went through.

Hopefully they help inspire you.

[here.now]

Coming up with a design for stands for my NatP's was the most frustrating part of the entire build. Here are a few of the iterations I went through.

Hopefully they help inspire you.

wkhanna Do you have any schematics for this build? I'm looking for tower plans for the Natalie P's and love the angles and the base.

[syzygylock]

My first cut out :/



Hi again, so I started to do the baffle cut out and attached is my first victim. One question, my ultra skill managed to make the tweeter cutout a bit misaligned, it's a tad on the left. Is that ok?

[PoorboyMike]

Not sure what you mean, are you saying the cut out and recess are not aligned? I can't really tell from the picture. If so, you can just file/sand the side that's off until the tweeter fits.

[fbov]

One could suggest that a practical tolerance on driver location is determined by the wavelength. At 11.3KHz, the wavelength is 0.1 feet or 1.2". You've only got about 0.12" (1/8") error so I think you're OK sonically.
Frank

[syzygylock]

I think fbov answered my question. Attached is the spaces that I mean.

[JonMarsh]

Not an issue other than appearance. Would make at most a tiny, virtually unmeasurable shift in vertical polar response.

[wkhanna]

wkhanna Do you have any schematics for this build? I'm looking for tower plans for the Natalie P's and love the angles and the base.

Here is a link to my build thread.

Please let me know if you have any questions, I would be glad to help.
I have some AutoCad files if you want or can use them.

[syzygylock]

XO build questions

So finally I finished making holes in the PE cabinets and everything is set for the XO build. I have a couple questions.

1. The PE cabinet's internal brace hole is only 6" wide, so whatever I build the XO on it has to be small so I can slide it in the back. The images of the XO from other builds are pretty big, can I still do it and fit it in? The reason I asked is that I read the website about the inductors placement and I don't think I can fit all of the XO parts on one piece and slide it in the internal brace's hole.

2. Or can I split up the XO into 2 or 3 pieces and glue them to the sides?

Thanks,

[ThomasW]

Take the largest board you can fit through the hole and try the components on it. The hole in the PE brace can of course be modified...

The board in this pic is 6.25" x 7.25"

[syzygylock]

Thanks Thomas, but what worries me is the coils' placement. From the website that was linked in the original NatP's thread, the coils should be 20cm apart or 10cm if placed perpendicularly. If I crunch it down too much it might become bad?

So I was wondering how Evil_Twin does the crossover and slide it in to the PE's enclosure.

[ThomasW]

Dozens and dozens of people have built this speaker following the layout in the photo. I'm sure you can do the same.

[---k---]

Remember, those distances are from center to center, not edge to edge. big difference with big coils. Also note that perpendicular coils touching is listed as "even this is OK". I've done several crossovers with perpendicular coils touching.

[syzygylock]

My XO and possibly a bad capacitor?

Attached is my mock of the XO on the board that would fit on the back side wall of the PE box. I used a different looking inductor and I tried to place it so that the wire runs like what the main thread. Is this ok?

When I build this I noticed a capacitor that looks "off" (attached), is this fine? Thanks,

[---k---]

Uh-oh. An iron core inductor. That isn't approved!

Some-what kidding, some-what serious. I'm sure the iron core inductor was much cheaper. And, I'm sure if you ask around the net there are people who have built these with an iron core instead and were happy. But, understand that there are two issues here: 1) The iron core has less DCR than the air core. The air core selected was a big thick 12ga to have a low DCR, but it likely will be somewhat higher than the iron core you have. This could cause a slight rise in the bass. (It would be much larger if swapped a iron core for a 18ga air core). You can correct for the DCR difference by adding a resistor of the difference in DCR value in front of the inductor. 2) Iron cores can cause distortion when driven hard due to what is called "saturation". Jon and Thomas have reported hearing this in some commercial speakers. I'm not sure how common it is. But it is a possibility.

Those are the issues. Neither way will cause your speakers to blow up. So, you're safe. You just have to decide if it is worth the extra $$ to be a perfectionist and get the last few drops of performance out of the drivers.


As for the cap. Probably okay, but why screw around. It is a $5 cap. Just replace it and not loose sleep over it. If you have an LCR meter or a Woofer Tester, you can test it.

[ThomasW]

Uh-oh. An iron core inductor. That isn't approved!

It's a laminated steel inductor not an iron core.

That said it should be laying down not be positioned standing on end...

The capacitor is damaged to the point it needs to be replaced.

The orientation of the components on the board isn't set in stone. Items can be moved closer together and or moved 90 degrees to effect a more compact design, as long as the wiring of the components doesn't change.

[---k---]

It's a laminated steel inductor not an iron core.

Okay. Oops. Educate me a bit. Still, same problems though, right?

[ThomasW]

Ferrite (powdered iron core) saturate easily and are to be avoided The same is true for the solid steel core inductors where the steel is a solid metal rod (round or square).

Laminated steel while not as good as air core, are an acceptable low cost alternative in most applications

[syzygylock]

I wasn't trying to save money, I following the BOM posted in the original post and it told me to get the 1.2mH from Madisound and this one (the one that I used) is the only one that matches the description. Also, I checked the DCR values (only 0.12 ohms) and it seems to be lower or the same of the equivalent air core inductor that people used.

This is my first time ordering anything to make speakers so I thought I have follow the BOM right to the last detail. For example, the 0.5 ohm Mills resistors were used in-place of the 0.47 ohm resistor from the XO drawing. That is why I have many questions that seems so trivial. But live and learn right ?

And thanks to all of you to help me along the way. I really appreciate it.

One last note, I was standing up the inductor because it is close to the 0.2 mH inductor, if I lay it down it would need to be 20 cm apart or it will violate the coils practice doesn't it?

Also, since we're on inductors, I got these:

Madisound 0.45 mH 19 AWG Air Core Inductor
Madisound 0.2 mH 19 AWG Air Core Inductor

The wire size is not too small is it?

[ThomasW]

Lay the big inductor down and let's stop ruminating on the inductor spacing....

The 19 gauge inductors are fine...

[syzygylock]

My first XO for Nat P

But it looks like a monster. It took me 4 hours to build it. I tested it and hearing sounds so that must be good right? Is there anything I should watch for when testing?

I am about to put in the acousta stuff into the cabinet, and I have a question about it. Do I put it in on the XO board or put it around the XO board? or it doesn't matter?

[Johnloudb]

I tested it and hearing sounds so that must be good right? Is there anything I should watch for when testing?

Yes, sound is better. :T And sparks, flames, or explosions would be bad. But you probably know that. If it sounds good then you've probably done everything, okay.

[syzygylock]

Cool...The only thing was that I was testing the sound on tv channels and couldn't hear any heavy bass but everything sounds great, need to test some CDs tomorrow to make sure