Natalie P build

[---k---]

Well, I guess you'll just have to veneer the front to give you that bit of extra depth.

I'm usually too deep and having to build up. It is hard to tell from the photos how bad it is. I wouldn't sweat it much. The great thing about wood, is it is pretty easy to fix mistakes. You can sand the openings with a dremel tool pretty quickly. Also, don't think that you need extra depth for the foam seal. By the time you tighten the driver down and use it for a few months, the foam seal will come will compress to paper thin.

[bbcmp1979]

---k---, great idea, I've never done veneer before. I might need to start doing that just for the front and paint the rest of the enclosure.

[---k---]

Yeah, wood baffles on a black box (or vice versa) can look real good. Might want to look for a nice long vertical wood grain veneer.

[bbcmp1979]

So I stopped by Homedepot today to check out their pvc pipe section. I picked up 1 4" x 2' of pvc, 2 4" caps, and 2 4" 90 deg elbow. The elbow measured ~11.5" long. with 1.93 ft^3 w 4" elbow bend would put me around 35hz. If I just use the straight pipe w/9" would put me at 38 hz. I would hope I'll be happy at 38hz.

Curt, would I need to flare both ends of the sub or just flare the outside?

[bbcmp1979]

Ok, so I got the pipe cut to 10", and not sure if i want the port on the back panel or the front panel yet. Any one have pics of the port on the front?

[bbcmp1979]

Built one crossover last night, all bracing installed to cabinet, and my camera went out of battery.. :-)

[gregnash]

bbcmp where did you find the design sketches for the NatP towers? I have been looking all over and cant seem to find any documented ones? Or is this something that is your own personal design?

[JonMarsh]

If I recall correctly, the Ministatements used a tuning of 35 Hz, and sounded quite good in my listening room. The predicted f3/f6 was 40 Hz/32 Hz respectively. For most music this low end extension will leave little to complain about. Jon's tuning would provide even more extended bass, albeit with a more polite presentation. Depending on the room size and speaker placement either tuning will work well.

C

Yeah, that's me, always being polite! :B

What works best depends on your goals and room placement as Curt states. It depends where the reinforcement points come in relative to boundaries-

This post on boundary loading may be helpful from a conceptual viewpoint- the basic analysis isn't hard to do.

ET on Boundary loading

Overall, the desirable thing to do is to maintain golden mean ratios between boundary distances (floor, back wall, side wall) and adjust the overall distances based on the Fs and slope of the speaker. Easier to play with setup and measure in many cases. But keep that golden mean ratio to avoid the boundary effects piling up on each other, creating peaks and nulls.

[bbcmp1979]

Great info John, my current setup is pretty close to the corner. I'll check my distances before speaker placement. I'll probably pick up some measuring equipment too to help with best location.

[bbcmp1979]

Greg, do you mean the baffle template? It's cut with a laser cnc at work. if you need it, I can email you the .cam file that and you can try to print it out as a template.

bbcmp where did you find the design sketches for the NatP towers? I have been looking all over and cant seem to find any documented ones? Or is this something that is your own personal design?

[gregnash]

Greg, do you mean the baffle template? It's cut with a laser cnc at work. if you need it, I can email you the .cam file that and you can try to print it out as a template.

Actually I was looking for general schematics (or drawings) for the Nat P towers in general but after doing a page by page search I ended up finding one. Looks like the height of the towers is about 42" standard? I think I am going to build the version with the bottom port and then build them up via stand base/legs as rule of thumb (I thought is that Tweeter height should be at ear level) and the 42" would put them at about chin level for both me and the wife...Thanks for the help though and I may take you up on that .cam file in the future ;x(

[bbcmp1979]

Greg, the baffle drawing is on https://www.htguide.com/forum/showth...t=13969&page=1 . I kept the same baffle width, i raised my towers to 40" high and 12" deep. I would of course have to build a set of stands to raise it a bit after they are completed. Here are two sketchups I just made





could some one please check to see if the inductors are ok?

[---k---]

The inductor placement looks good.

IMHO, wiring the crossover on the underside looks good, but it makes it harder to mount on the side of the box.

[gregnash]

Thanks bbcpm... It seems like everyone kinda comes up with their own dimensions for the tower version of the driver.

This is the one I was referring to... https://www.htguide.com/forum/showpo...&postcount=280

[gregnash]

Ok not sure how to calculate the enclosure volume on this but if I too bbcpm's design and extended it to 44" tall how much of an increase would that give me in size? Also, I am thinking of tuning this to ~34hz... which I can then find out the length once I figure out the enclosure volume (thinking of a 4" port).

[bbcmp1979]

~ 2.10ft^3 with a 4" port at 10" long.

ok Greg, I lied. I just checked my calculations. You'll have a tower /2.03 ft^3 or 57L.

[fwrigley]

Greg, the baffle drawing is on https://www.htguide.com/forum/showth...t=13969&page=1 . I kept the same baffle width, i raised my towers to 40" high and 12" deep. I would of course have to build a set of stands to raise it a bit after they are completed. Here are two sketchups I just made





could some one please check to see if the inductors are ok?

Looks good. What are your plans for the stands?

[bbcmp1979]

fwrigley, good question, I haven't figure it out the stand for it yet. But I do like simplicity so it shouldn't be long til I have it.

[gregnash]

fwrigley, good question, I haven't figure it out the stand for it yet. But I do like simplicity so it shouldn't be long til I have it.

I am with you, I like simplicity and elegance in something like this (starting to consider a curved design which I have only see one person do). I was simply thinking of doing 4 half inch doles that would connect to 3 sheets of 3/4" either MDF or veneer plywood with the center piece having a hole cut in the middle that would have something heavy in it to keep the speakers solid to the ground.

Something similar to this... http://www.revelspeakers.com/

[bbcmp1979]

That does looks nice!!!

[bbcmp1979]

Crossover mounted and wires routed (sorta). Should have moved the port up higher so I can have a removable crossover.

[Blazin_Jason]

Nice work. I've really enjoyed my Nat P's for what I needed. Hopefully in a few months I will have some time and money to build another set for the rears.

[bbcmp1979]

So I loosely placed the baffle to the tower and hooked it up to my receiver this morning.

First off, I definitely need to upgrade my receiver. I'm currently using a Yamaha HTR5730, which was a 5.1 hometheater in a box. It used to drive really small speakers.

Now it is driving a set of EMPTEK EF30C (6ohms) for my mains. It does great for the EF30C but it seems that the Natalie wants more power.

So I hooked up the receiver and had to turned up the volume to -20db as oppose to -35db for the EF30C. Even at lower volume, I can hear much cleaner, crispier highs, a lot more revealing, and a lot more detailed compare to the EF30C. Peoples' voice are quite a bit more natural compared to the EF30C. On the EF30C, the SSSSS sounds very pronounced, the Natalie P is more detailed but there was no fake SSSSS sound.

My net volume for the tower were 1.80 after port, drivers, bracing, and the crossover displacement. At 10" long for the port, Winisd gave me a tune of 38.18. I almost detect no bass coming out of the tower. My only guess at this point is the baffle was just loosely placed against the tower which would cause this. I might as well just hook the baffle up and have a quick listening test w/o using the tower.

[Blazin_Jason]

Once it's completed you will hear just how well those 6" drivers can produce some lower end bass. Last night during a movie I was watching I paused it to get up for a second. I was going to go outside and see who was playing bass in their car for a couple minutes outside my house. Turns out it was the movie with bass in the background. It had me completely fooled.

[bbcmp1979]

Blazing, I'm pretty sure what i'm hearing is due to the fact that the baffle is not glue to the tower to create an enclosure. I am happy with the midranges and HF though. It is way more detail and revealing than the EF30C could ever hope to do :-). I do have a 12" in a corner to enforce the low end when needed.

My original goal was to get cleaner midrange and more detail to keep up with the sub. So far, with just 5 minutes of testing, the Natalie accomplished that nicely.

[gregnash]

You wil have to give us a full review once you get them glued together. I plan on building these later in the year and plan to use them for 60% Movies/Games and 40% Music(streamed from my Xbox 360). Also plan on building a, probably, 15" sub to take up the low end.

[bbcmp1979]

i"m away for a business trip, and I'll be back next weekend. As long as my wife doesn't move things around in the garage, things'll get done much quicker.

[bbcmp1979]

I took a pic of the natalie sitting in the living room. Need some finishing touches... Now If I can find a painter.

[evilskillit]

Looks pretty sharp. Will come together nicely with some paint.

The tape over the tweeter flanges really threw me off. At first I thought those were just 2 random tweeters slapped into the cabinet, then I looked at your parts pictures, and closer ant the built pictures and figured it out.

[numberoneoppa]

Haha, yeah, what's with the tape? Took me a second to figure out what the heck you were doing, too. Anyways, they look great. Is it me or did you not even bother blowing off the dust before bringing them into the house? Yes, excitement can get the best of us sometimes.

[bbcmp1979]

I'm using the hurricane nuts for Rs180 and screws for the tweets. The tape hold the tweets temporarily for testing. I don't want to install and remove screws too many time on the tweets. They won't bite after a few removals.

[numberoneoppa]

Oh, I see. I used t-nuts with hex-cap bolts for my tweeters. I don't think I'll ever used screws just for the issue that you pointed out.

So... how do they sound? Hopefully better than those plastic speakers that you're using as stands in the background. :P

[bbcmp1979]

They are very detailed, opened, and very revealing. I heard stuff that weren't there before watching Transformer2 last night.

I had a stuffed them with R13 on sunday night and they sound stuffed. The bass weren't there, until last night when I removed quite a bit of it. R13 when fully expanded was like over 4" thick.

Once removed, the bass was more opened and the Natalies breath much better. I was able to listened to music w/o the sub. The low end bass are much more extended now while midbasses are pretty accurate.

On the high end frequency, they are a lot more revealing. You can hear a singer breathes. Speeches are very clear and realistic unlike my plastic speakers (fake rumbling (man) voice).

Overall, I'm very happy with them last night.

Thank you to Jon's for suggesting that R13 would be way too much damping the Nats, I would not be as happy as I am now.

:-)

[bbcmp1979]

So I placed the speakers toward the corner, used the plastic speakers as stands, and removed even more R13 from the enclosure. Whammmm, extremely low bass extension. I felt just a tiny bit of vibration from the floor. I didn't expect that the Natalie would go this low... They were clear, articulate and very crisp. I listened to about 3hrs of music w/o fatigue.
The receiver is a yamaha HTR-5730, which is an extremely low end receiver. I detect no distortion through the speakers even at -16db. I used to listened to -30db, any louder on an older setup and it would distort.

I took a pic of the natalie sitting in the living room. Need some finishing touches... Now If I can find a painter.

[fbov]

In a ported enclosure, you line the walls to absorb frequencies above port tuning and perhaps use a little fiber fill to fine tune the sound - the the interior of the box needs to be substantially empty. I have 1" accoustic matte on all my interior surfaces except the front baffle and bottom. Since I have a bottom port and tall (40") tower, I've added fiber fill next to the port to minimize the box length standing wave. I also tuned low, and like you, have the port firing into a corner to maximize room gain. Measured in-room response drops like a rock at 30Hz.

You may not have had too much R13 so much as you had it too fluffy. 4" on walls that are 7.5" apart leaves no space for the port to resonate, and a ported box needs to resonate. You've removed some and are now pleased, so the following is more for your understanding than anything else.

The R13 would have been fine if you had compressed it tight to the walls. Thermal insulation is all about trapped air; accoustic absorbtion is all about complex air paths; compressed fiberglass board is an excellent sonic absorber. It wasn't the amount of R13 that hurt the sound so much as its presence in the volume of the box where it prevented port resonance. Had you tacked it against the walls, no more than 1" thick, you'd have the same bass improvement with a bit better back wave damping above port frequencies.

And I don't use T-/hurricane-nuts unless they're needed and this isn't one of them. I have no problems getting MDF screws to hold over multiple insertion cycles in a pre-drilled hole, but I also re-install in the same threads it cut the first time. I have seen blind T-nuts come loose, to great consternation of the builder. My speakers use T-nuts, but only for the spiked feet. YMMV.

Have fun,
Frank

[bbcmp1979]

I started primering one of the natalie last night. Ohh, the long treaded process of primer, sand, primer, sand, primer, sand, more primer, and sand.....

I did 3 coats of primer already, hopefully just one more coat to smooth it out a little bit more and I can start the next cabinet.

[numberoneoppa]

Great to see that they sound nice! Yeah, I use r6 hobby insulation for my speakers which is 2 inches thick. I peel it down to 1 inch in some areas, seems to work very good. You can find it at HD and Lowes for 4 bucks a roll (one roll per speaker, about, depending on size).

[evilskillit]

Lookin good, can't wait to see your finish. Btw, in case nobody above me pointed it out, you've got them backwards, the tweeters go closer to the inside not the outside, or closer to the middle how ever you want to look at it. Try that when you put them in next time. I don't know if it'll make an audible difference but that is how they're designed to be listened to.

As for what previous posters have said about t-nuts, there was a great thread on this forum earlier about putting a touch of gorilla glue around the outside of the t-nut before you install it. Seems to make a world of difference, I think the metal threads would strip before it would come loose after having done that.

[gregnash]

Lookin good, can't wait to see your finish. Btw, in case nobody above me pointed it out, you've got them backwards, the tweeters go closer to the inside not the outside, or closer to the middle how ever you want to look at it. Try that when you put them in next time. I don't know if it'll make an audible difference but that is how they're designed to be listened to.

As for what previous posters have said about t-nuts, there was a great thread on this forum earlier about putting a touch of gorilla glue around the outside of the t-nut before you install it. Seems to make a world of difference, I think the metal threads would strip before it would come loose after having done that.

LOL... was looking at that last night and thought something looked odd. Didn't know for sure if the configuration would make that much a difference or not. :rofl:

[fbov]

In truth, tweeters-in vs tweeters-out is a matter of personal preference and application. Most speaker designers have a dedicated listening environment where speakers can be placed in their optimum locations. Most speakers exist wherever there's room in the living environment.

There might be a discernable benefit to one or the other in a corner location such as yours; try both and see which you like better.

Have fun,
Frank

[---k---]

Agreed. My tweeters are on the outside to benefit off axis listeners.

[bbcmp1979]

I've had the tweeters placing both on the inside and outside. The inside had awesome imaging, and the outside provide a wider range or sound field. Once they are finish, I'll probably place them on the inside to to minimize reflection of the window.

As for the hurricane nuts, I had some polyurethane caulk to reinforce them in place. They are much easier to installed compared to t-nuts.

[bbcmp1979]

lease do not mind the dusty floor. This is after 4 coats of primer and sanding in between coats.

After 3 coats of Semigloss black, it might be too glossy sitting next to the TV. I might have to repaint it with flat black. I have a buddy coming over tomorrow so there probably won't be any work done to it til saturday (sanding the first 3 coats).



Second one almost ready for primer.

[numberoneoppa]

Hard to tell from the pics but they're looking pretty good to me. How long do you wait before sanding with that particular spray primer? Do you wet or dry sand?

[bbcmp1979]

about 30 minutes then I applied another coat. I was going to use a paint brush but that would probably make it look really rough. I had a bad experience with paint brush a few years back.