Kirk's NatalieP Build

[kirknelson]

I actually began this build about a week ago but am just now getting around to posting about it.

Ultimately I plan on using the NatPs as surrounds in a system with Khanspires and a WTMW Center up front. Since I'll be using them as surrounds on stands, I chose to build the cabinets to the published 1 cu. ft. dimensions. I am building my own cabinets rather than using the PE ones, primarily for the experience of building them before taking on more challenging builds. Also, as these will be used in a complete system I wanted to finish all the speakers so they match.

For those that are curious, the front end for this system will be: an HTPC, an HK AVR525 (used as a preamp) and an Emotiva XPA-5.

On to the build...

I serve in the US Navy and one of the unexpected benefits of that is access to my base's woodshop which is fully furnished with commercial grade equipment (primarily Delta) for a mere $3.50 per day. After my first visit I had all of my boards cut, but will have to go back to do the cut-outs in the braces.



I'm using 3/4" MDF only. It didn't make sense to me to purchase a sheet of 1/2" just for the second baffle sheet and braces when I could cut those out of the 3/4" for no additional cost. This is the front baffle boards being fused into a 1 1/2" sheet.



Next came the side walls and end pieces.





Yesterday I took the router to the baffles and cut the recesses and holes. I used the jasper jig and was suprised by how easy and smooth it all went. I think the hardest part was drilling the guide hole in the exact right spot. That and breathing with all the MDF dust in the air. :P

I'm pleased with the way they turned out but I think eviltwin's published inner diameter is a little small. That or they changed the dimensions of the RS180. I had to do quite a bit of sanding to allow the driver to slide in smoothly. I had another disapointment due to my failure to fully review the plans. I had intended to use a 1" round over on the baffles but after cutting the recesses I realized there wasn't 1" of space between the recess and the edge. I had to put finishing the baffles on hold and order a 1/2" round over bit from MLCS. At least I get a new tool right? :T



Last night I veneered the rear panels using the iron on method. I used Titebond II and applied it to both the paper backed veneer and the MDF using a foam roller. This seems to be the best way to do it and it worked well first time through though I needed to go back over my corners. If you try to use this method be aware that the foam roller soaks up a lot of glue. Use the smallest, thinest roller you can find to minimize your waste. I also think it's better to squeeze the glue onto the piece and then roll it even rather than using a pan and painting it on.

Today I cut the recess and holes for the port. It went smoothly again but I got a bit of chip out in the veneer. I was using a spiral upcut bit and I think I should have been using a down cut. ops: The chip out isn't too bad though and it is the back of the speaker. I'll know for next time and that after all was the point of building my own version of the PE cabinets.

Does any one know of a good way to repair this damage? Will a stainable wood filler look alright in a veneer?



Next up: Crossovers

[Tsloms]

This is the kind of bit you want to use for opening up the driver holes. These are solid carbide bits and helpful for when you do not have clearance for bearing depth such as on tweeter holes.

Depending on how bad the damage is you could use a little wood putty.

Image not available

[ThomasW]

Does any one know of a good way to repair this damage? Will a stainable wood filler look alright in a veneer?

If you're going with the recommended flared port, you might luck out and the flare itself will cover the damage.

Otherwise I'd fill the damage and paint a black circle around the port opening. That way you don't need to hassle trying to match any grain.

[kirknelson]

Thanks for the replies. I am using the flared port but I recessed it so it won't cover the veneer. The chipping isn't too bad and I think it will look better after a little sanding.

I had read that the best way to veneer a recess is to put the veneer on first and then cut the recess. In this case a laminate trim bit wouldn't work. Had I cut the recess and then veneered over it I would have been able to use a bit like that.

[---k---]

I wouldn't worry about a small spot on the back of your speakers. I've got big chips and problems on the front of my speakers that most people don't notice until I point it out.

That said, I've uses stainable wood filler. It takes some stain, but it is easy to spot it if you go looking for it. I seriously wouldn't worry about it.

BTW, where are the speaker terminals going to go?


Now lets get on to the Khans!

[kirknelson]

I'm using straight through PE binding posts which I will drill holes for. I just wanted to complete the x-overs first and get an idea for where they will be located before drilling.

I think the Khans are going to be alot of fun, but I can only handle one project at a time.

[kirknelson]

Starting to wire up the crossovers and I had a quick question. Does it matter which end of the inductor is wired to each component? I.e. should the coil's inner wire be the "input" and the outer be the "output?"

I'm thinking it doesn't matter but just wanted to make sure.

[ThomasW]

Inductors, standard caps, resistors, etc, don't have a +/- (or an in/out). If they did, that information would be referenced in the crossover schematic

[kirknelson]

Thanks for the quick reply Thomas! I didn't think it would, but better safe than sorry. :T

[Blazin_Jason]

There is lots to learn doing your first diy speaker build. I know I learned a lot building my nat p's. Looking good so far!

[kirknelson]

This was definitely the most time consuming and challenging portion of the build so far. However, the crossovers are finished, and a continuity check confirms all connections are good. 8)

[kirknelson]

Time for a build update.

The rear panels being glued into place. I used blocks of scrap MDF to prevent the veneer from being marred by the clamps.



I glued the fiberglass in place using a spray adhesive. It still needs to be fluffed in this image. The crossovers are also glued into place.



Then it was time to glue the front baffles into place. Notice in the second image the tweeter back plate was also glued into place and the baffles have been rounded over.





I did hook up the drivers to the crossover with out placing them in the cabinets and everything seems to work great. That little taste whet my apetite and I can't wait to get these completed and do some listening.

I'll be glueing on the veneer and finishing the cabinets next

[ThomasW]

That's quite a bit of damping. You don't want to 'fluff' it. There should be no damping in the area of the port.

When you test it and if the output from the woofers seems too low in comparison to the tweeter, peel off and remove some of the glass.

[kirknelson]

How much space should there be between the port and the dampening material? I dry fitted the port and there doesn't appear to be any air flow restriction between the port opening and the rest of the cabinet.

[ThomasW]

Wiring the inside the cabinet.

[kirknelson]

I was concerned about Thomas's comment so I went ahead and dry fit the drivers and port into the cabinet to see how they sound. First I have to say, WOW these are a huge step up from my Paradigms! So much more clarity, depth, height and the soundstage is huge! Imaging is remarkably focused as well.

To my ears though, it does sound like the lower mid-range is sucked out in comparison to the upper mids and treble. This may be caused by my own perception and familiarity to how my music sounds on less accurate speakers, but I believe it is more likely due to having too much fiberglass in the speaker as Thomas suggested. I'll pull some of it out (looking at your pic maybe a lot of it). Thanks for bringing this over sight to my attention.

[ThomasW]

That's a pic of the NeoDcc not a NatP, but they use the same cabinet.

This is a minitower NatP.

[TacoD]

Yesterday I took the router to the baffles and cut the recesses and holes. I used the jasper jig and was suprised by how easy and smooth it all went. I think the hardest part was drilling the guide hole in the exact right spot. That and breathing with all the MDF dust in the air.

Yeah working inside without a proper vacuum cleaner is not recommended Before I forget great project.

[kirknelson]

It has been awhile since my last post. As I mentioned before I'm in the Navy and my ship has been underway for the past month. I got back last week and the speakers are now DONE! 8)

When I last left off I was applying the veneer. Here are the veneered cabinets:





The only thing left to do after that was finish the cabinets and then insert the drivers, ports and binding posts. I finished the cabinets using Minwax walnut stain and a polyurethane topcoat. The baffles are high gloss black, even if they don't really look it. I made a mistake with the paint by going with the cheap stuff and becuase of that ended up with a lot of brush strokes. Next time I will go with a higher quality product and maybe an oil based rather than water based paint. I tried sanding the paint to get rid of the brush strokes but the finest grit that they had at the local big box was 220 and that ate right through the paint. Finally I remembered reading this thread and drove over to a local auto parts store to pick up some rubbing compund/polish. While I was there I noticed that they carried much finer grits of sand paper, all the way up to 2000! So I picked up those as well as the polish and the brush strokes are no more. For any one having trouble locating fine grits for finishing your cabinets try swinging by your local auto parts dealer.

Here are the finished cabinets:





Here they are in their temporary homes atop my old Paradigm Monitor 5s. Poor speaker stands I know, but it is only an interm solution while I work on my Khans.









Overall I'm pleased with they way they turned out. They certainly aren't perfect but I think they are actually quite good for my first try. ops: I certainly learned a lot building the NatPs and now I have more confidence to jump into a more complicated project.

Coming soon: WTMW Center channel and Khanspire mains!

[---k---]

Yeah, but how do they sound?

[kirknelson]

I'll let you know in a couple days. They're currently breaking in with a little Bela Fleck.

They do sound substantially better than my Paradigms already, though they lack the bass extension of the Monitor 5s. I think this will get better after the drivers break in a bit. It could be the Paradigms were a bit warm too and my ears are just used to the way they colored the sound.

[Dean100]

Those look great! Very nice work for your first build. :T

[kirknelson]

I let the speakers break in for a good 40-50 hours with a variety of music and finnally sat down and did some critical listening today.

I listened to a variety of music including classical, jazz, vocals, rock and some dance music and the NatPs sounded great with all of them. Orchestral music is notroiously difficult to reproduce truthfully due to the scale of the presentation and the NatPs fell short of an "I'm there" moment. However, the detail, especially in the lower octaves was astounding. The resonating tones of the basses and cellos held a remarkable presence that I have never heard before on a sub $3000 speaker (excepting the Vandersteen 2ce). Imaging was also impressive though I found it somewhat difficult to pick out individual instruments, sections and soloists were easily located.

The NatPs were more impressive on more intimate recordings of small ensembles as well as on jazz, vocalists and rock. The soundstage extended well beyond the speakers though I felt a lack of depth on some recordings. The overall tone was very neutral and really showed me how colored my Paradigms are. By comparison my Monitor 5s are bright and harsh with a definite mid-bass bloat. I had previously mentioned that I though the NatPs lacked the bass extension of the larger Monitor 5s, but I was wrong about that. After they had broken in it was very clear that the NatPs reached deeper and with more authority than I had expected. It's kind of a cliche thing to say in the audio world but I was hearing detail in my music that I had never heard before.

While the area the NatPs shine the most is undistorted detail, I think the area that impressed me the most was their dynamics. Everything simply sounded so effortless, Billy Corgan's vocals stayed rock solid in the center while the kick drum hit me in the chest, ATB's sparkling electronic notes danced around the room while the bass rattled my walls and dialog remained intelligible while gun shots startled.

Overall, I am extremely impressed. Bravo to all those responsible for the development of these speaker they sound far better than they have any right to given their cost. If I was going to compare these speakers to retail models I think you'd have to get into the $2500+ price range to find some contenders. Since they cost me a little more than $600 to build I think that is simply amazing. Especially since the my Paradigm Monitor 5S cost me $550 10 years ago. With inflation I'd guess that to be about the same cost if not a little less for the NatPs. :E

Here's my material list:

QTY   	PART NUMBER   	PRODUCT   							PRICE  
2  	004-20  	Dayton DNR-20 20 Ohm 10W Precision Audio Grade Resistor		$2.50  
2  	004-6  		Dayton DNR-6.0 6 Ohm 10W Precision Audio Grade Resistor		$2.50  
2 	266-355  	1.2mH 14 AWG Perfect Layer Inductor				$42.74
2  	266-806  	0.20mH 18 AWG Perfect Layer Inductor				$9.06
2  	091-1245  	Dayton BPA-38G HD Binding Post Pair Gold			$15.78
2  	004-.51  	Dayton DNR-0.51 0.51 Ohm 10W Precision Audio Grade Resistor	$2.50  
2  	255-226  	Jantzen 0.44mH 18 AWG Air Core Inductor				$10.20
2  	268-348  	Precision Port 2" Flared Port Tube Kit				$19.30
4  	295-364  	Dayton RS180S-8 7" Reference Shielded Woofer 8 Ohm		$157.56  
2  	275-130  	Dayton RS28A-4 1-1/8" Aluminum Dome Tweeter			$97.30 
4	027-200  	Dayton PMPC-0.10 0.10uF 250V Precision Audio Capacitor		$5.16  
2  	027-210  	Dayton PMPC-1.0 1.0uF 250V Precision Audio Capacitor		$4.06  
4  	027-214  	Dayton PMPC-2.0 2.0uF 250V Precision Audio Capacitor		$9.64  
2  	027-220  	Dayton PMPC-3.0 3.0uF 250V Precision Audio Capacitor		$6.38  
4  	027-244  	Dayton PMPC-10 10uF 250V Precision Audio Capacitor		$30.60  
4  	027-246  	Dayton PMPC-12 12uF 250V Precision Audio Capacitor		$35.48  
2  	027-258  	Dayton PMPC-30 30uF 250V Precision Audio Capacitor		$37.44   
											--------
PARTS EXPRESS TOTAL									$488.20

2" Fiberglass Insulation								$7.90
Screws											$4.00
Weather Striping									$3.09
Veneer											$57.74
Paint											$12.49
Stain											$11.84
4 24"x48" sheets 3/4" MDF								$35.08
											--------
BIG BOX TOTAL										$132.14

-------------------------------------------------------------------------------------------------

PROJECT TOTAL										$620.34