The Natalie P Maxx's

[speedle]

In an inexplicable fit of complete newbie-ness, I have:

a. Not documented about two thirds of this project, and;
b. Posted all my questions, comments, and other asides in the Missions Accomplished Natalie P thread.

Therefore, I don't know how long this thread will end up being, but I'm going to try, over the next several days, and rectify those errors. I say that mainly because I'm just so darn thrilled with the sound that these things make, I can't hardly get up off the couch!

I'll begin by posting the little photo of these, in their 95% complete state, from the other thread.

[joecarrow]

They look super! I bet that they sound even better than they look. I can't wait to read about them.

[BigJim_inFLA]

Looking good! What drivers did you use in your bass bins?

[ThomasW]

Alright someone finally built some bass bins, way to go... :T

[speedle]

Actually, the bass bins are what prompted this project, I don't know how long ago. I always wanted to have fairly tuneful bass that wasn't dependent on a ported design, because my room seems to have more modes, nodes, nulls and peaks than you can shake a stick at. My ADS L620's are sealed, as were a pair of original Advents that I restored and sold. I liked how they sounded, and seemed to be alot less fussy about room placement.

So I knew I wanted sealed, powered, maybe very slightly underdamped bottom end, but the trick was always finding the high output/low distortion top half to mate with it. So really, finding the Natalie P design was just the answer to my prayers, so to speak.

Having built the Adire Bang! project, the Shamrock SE-2, and started to build the boxes for a pair of North Creek Rhythms, I know I like the way MTM's image, but they also seemed to need space to integrate, and I thought the SE-2's a little forward. Also, even though I can listen to my Paradigm Reference Studio 60 v.3's for a long time without fatigue, I did want a little more dynamic capability and snap. See why I'm so happy with these?

Back to the bass bins. I really liked the North Creek way of building cabinets, so that's the template I used in designing these. Although in this case they're kinda inside-out, being 3/4 inch MDF surrounded by 3/4 inch BB plywood from Lowes (which they cut for free!).

Tomorrow I'll write down some of the history and details, and try to scan my first two sketches I did a year ago. Which, shockingly, seem to resemble a certain Wilson product, and to which everyone who looked at them said, ewwww no!

[wkhanna]

Looking forward to info on your BB's!

[speedle]

Well, here's pretty much the rest of it, near as I can tell. If the pics are too much, let me know and I'll get rid of 'em.

The original concept -

Which then became -

But then I saw these Aerial prototypes (notice the one on the right)

First I had to get drivers though. 30 years ago I made a subwoofer from the 11” unit in a Realistic Optimus 9 that had a damaged cabinet. Always wanted to do that again, but better. So, off to eBay…



Notice how the woofer on the left (the correct one for this model), differs from the right (substituted one)? Sure wish I had before I bought them. So, back to eBay…



These are from NOS, destined for the Realistic Optimus 5B. Not exactly what I wanted, but close enough for now. Off to Madisound for…



A pair of NHT10 woofers from their close out sale page. These are very ruggedly built poly cone woofers that appear to have some sort of textured carbon-fiber imitation on the surface. Makes them look really cool, at the very least! Then I bought two of these…



MCM Close-out 150 watt plate amps. 50 bucks each. One blew up, and took one of my matching pair of NOS woofers with it. This is just as well, because with a 6 db boost at 35 Hz they were un-listenable with a high Q woofer. So…off to PE for two of these…



From WinISD, here’s the NHT10, 12 ohms, in its 1.1 cu. Ft. box. Slightly smaller than optimal. Qtc at .74



And the group delay graph



NHT10 in 33 liter closed box, 50% fill.
Relative
Freq Gain Phase SPL
[Hz] [dB] [deg] [dB]
20.00 -13.38 140.35 71.62
25.00 -9.70 129.40 75.30
30.00 -6.91 118.00 78.09
35.00 -4.84 106.62 80.16
40.00 -3.34 95.78 81.66
45.00 -2.28 85.90 82.72
50.00 -1.55 77.18 83.45
55.00 -1.06 69.65 83.94
60.00 -0.72 63.22 84.28
65.00 -0.50 57.73 84.50
70.00 -0.34 53.05 84.66
75.00 -0.23 49.03 84.77
80.00 -0.16 45.55 84.84
85.00 -0.10 42.53 84.90
90.00 -0.07 39.87 84.93
95.00 -0.04 37.53 84.96
100.00 -0.02 35.45 84.98

Next, I added the Optimus 5B woofer, 8 ohms, in it’s 2 cu. Ft. box. Again, slightly smaller than optimal, with a Qtc of around 1.00, but definitely not bad at all extension-wise, f3 being around 32 Hz. At this point I was worried about boom though. By the way, the Optimus 5B TS parameters are courtesy of Ed Hanlon over at the Yahoo Realistic forum, as he tests these things from time to time.

Here's the combined SPL and group delay:





Optimus 5B in 58 liter closed box, 50% fill
Relative
Freq Gain Phase SPL
[Hz] [dB] [deg] [dB]
20.00 -11.51 147.30 74.49
25.00 -7.30 136.05 78.70
30.00 -3.98 122.64 82.02
35.00 -1.53 107.63 84.47
40.00 0.06 92.43 86.06
45.00 0.94 78.65 86.94
50.00 1.33 67.17 87.33
55.00 1.44 58.01 87.44
60.00 1.42 50.79 87.42
65.00 1.34 45.08 87.34
70.00 1.23 40.50 87.23
75.00 1.13 36.77 87.13
80.00 1.03 33.68 87.03
85.00 0.93 31.08 86.93
90.00 0.85 28.87 86.85
95.00 0.77 26.96 86.77
100.00 0.71 25.30 86.71

The total size of the overall cabinet was defined partly as a result of my wanting to maintain a certain visual proportion, with a manageable depth and weight. As it is, with the lower fascia, buyout spikes from PE, and PE buyout feet for the Natalie P’s, they’re about 4 inches higher than optimal for my listening distance, but manageable. I just have to sit up straight. And design-wise, I like the look of the exposed plys on the front of the B&W 802D, but in rectangular form.

Panels laminated with PVA glue (Elmer’s) for some CLD, and structural joints glued with Titebond wood construction glue. All walls are 1.5” thick, a lamination of MDF and BB from Lowes.

With the 300 watt BASH amps running into the slightly less than 6 ohm load of the two woofers paralleled, I estimate that gives me about 200 watts before clipping. With a combined average SPL in the 89 db range, I figure a peak anechoic SPL around 110 decibels is feasible, but I’m sure there would be smoke to accompany that as well.

Wheww...I need a drink now, and gotta get back to the couch for some sounds.

[speedle]

Bump...

New veneer for the Nats is here, new stain for the bass bins. It's all GOT to come together before March 23rd, which is the date I take them to Audiokarma's AK Fest 2007 and let, ya know, OTHER people listen to them!

[ThomasW]

I have no idea what you ended up using NHT or RS drivers, both?

[speedle]

Yes, I can see where you might not be clear on that. I am using the NHT in the upper 1/3 of the box, and the RS woofer in the lower 2/3. Though blessed with just a teeny bit of overhang, it works well for most of the stuff I listen to.

I didn't like the looks of my Natalie P cabinets though, and I'm presently re-veneering them with some birch I bought from Tape-Ease in Wisconsin. I'm already itchin to build new ones though, as well as Modula MT's for the bedroom, and jeez...something that looks like an Avalon something or other. This forum gives me SO many ideas, and tons of inspiration! ;x(

Results soon!

[speedle]

Much better veneer, VERY bad photos.

Please excuse the pics, but my cell is all I've got at the moment. Thought I'd post some progress pics for a change. It just kills me to stop and take photos though! This is new veneer and stain for the Natalie P's, and new matching stain for the bins. Minwax Sedona Red, the wife picked it out and I really like it. At least if she picked the stain out there's half a chance the end product will be alright in the living room.







Damn cell phone camera can't take a clear picture to save its life though.

[TacoD]

Looks very nice and good luck with your deadline .

[wkhanna]

Even with cell-phone quality pics, I can tell they look V nice.
Nice going, Speedle!

It's always a good idea to include the SO in decision making, too!

[speedle]

Done!

Stick a fork in 'em, I think they're done!



Coincidentally, this also shows the Slim Devices Squeezebox rig I'll be using at AudioKarma Fest 2007 next weekend in Southfield. Come and hear these if you can!

A few more:

[Exocer]

Wow, those turned out very well. Your setup has to sound sweet :T

[ThomasW]

Great job..... :T

You might want to face them toward the sofa for better on-axis response...

[speedle]

I don't want to drag this thread out any more, but I just want to post a quick picture of my exhibit room at AK Fest 2007, at which the Natalie P's received a fair amount of praise from visitors.