Natalie P towers, with a twist

[mrstampe]

After a lot of reading and advice from fellow Shacksters, I’ve decided to start out my 5.1 DIY surround with a set of Natalie P floor standing left and right channels. Eventually, these may move to the rear if I decide to build Dayton TMWWs for L/R and a Dayton WTMW center. Also, an SDX15 sub is in the works.

I plan to build the ported 50L version of the Nat Ps, but I’d like to put a twist on the design… or maybe a bend. I’m reasonably experienced in woodworking, though this would be my first try at panel bending. This can be accomplished by form pressing thin laminates into thicker panels, by saw-scoring MDF or Baltic Birch, by stacking “polylam” walls, or buying manufactured bendable ply. I'm not married to these plans, so I am open to creative ideas other than the standard rectangle.


See a few sketchup ideas at the end.


Bending techniques…

form bending


scored


bendable ply


translam




Questions:

1) The Swerve preserves the intended Nat P baffle dimensions, but the Vibe and the Wave are instead widen to 10” on average with curved edges. Will this affect the sonic qualities of the speaker?
2) Does anyone have experience with these bending techniques? Any advice?
3) Some building the 50L towers seem to prefer a higher tune (6” long, 3” diameter port = ? tune) to the designers recommendation of an 11” long, 3” diameter port for a 28Hz tune. Any thoughts on that?
4) Which design do you prefer?

[BoomieMCT]

Keep us posted on this. I love curved cabinets! I think one of the pictures you posted was cut in layers and glued, not bend wood.

As far as the baffles - making wider baffles will lower the point where baffle loss begins and may affect your crossover. This is not too hard to compensate for in the crossover with a little patience.

Also, I think the "wave" is the best design - but they all look great!

[ktaillon]

I like the wave the best also! I've been thinking about curved sides also, I was planning on using multiple thin (1/4) pieces of plywood.

I also through together a rounded back speaker..



Here's a different shape speaker, I just started work on these.


Or here is one that I haven't built yet(the wife thing)



You can see other pics at the link below...

[Anthony]

Cool designs. Keep us posted. (sorry I have nothing else to offer in terms of insight here )

[mlwebb]

re tuning, I just finished a pair with JonM's original crossovers (otherwise same speaker as the Nat P's, also 50 l towers, and I started with 3" precision ports with a 7" length (plus flare allowance), which according to winISD is a tuning of 34hz (not incl room) and they sound great. I am going to try a little shorter, 6-6.5 and see if it brings the 40-50 hz spl up a little.

[mrstampe]

mlwebb wrote:

re tuning, I just finished a pair with JonM's original crossovers (otherwise same speaker as the Nat P's, also 50 l towers, and I started with 3" precision ports with a 7" length (plus flare allowance), which according to winISD is a tuning of 34hz (not incl room) and they sound great. I am going to try a little shorter, 6-6.5 and see if it brings the 40-50 hz spl up a little.

Hey Michael, welcome to the Shack! You'll find some great discussions here with impressively knowledgible people. Regarding your Natalie P towers, we'd love to see them. You could either post a quick photo in this thread, or even better, you could start a new thread describing your goals, building process, several pics of its progression and your impressions of the outcome. It would also be interesting to get your evaluation of how the Nat P changes by increasing the tune (shortening the port). Thanks for joining my build discussion, and I'll look forward to seeing you around the Shack!

[Rodny Alvarez]

I like the wave,

The bendable plywood would be the easiest to build, they have two types of bendable, so make sure you get the right one (birch bendable plywood)

[bonehead848]

Wave FTW! The bendable ply would be the easiest but these high level mtm builds really can throw out a lot of bass. Is braced bendable ply really strong enough?

[mlwebb]

Well, I tried the six vs seven inch port, (36hz, vs 34hz box tuning), and listening to a few single tracks (from Acoustic Alchemy to Rolling Stones sympathy for the devil, a couple beatles tunes, a country song (Fred Eaglesmith) and a little Joe Cocker), with sub off, no measurement equip but old ears, and I think I'll stick with the six inch port for a while. It seems to give a little more umph to the bass drum, guitar low notes. I think Jon originally tuned the smaller box version to 32-33 hz, so its worth trying a few port lengths to see what works with your room, and whether a sub will be used. They go very loud comfortably, not that I really crank them often, and sound very good. Sure you will be happy with yours

Here's a picture of mine, design(pdf) and finished(jpg)
http://www.mlwebb.com/pdf/mtm2f.pdf



I consider myself a pretty experienced woodworker (new to speakerbuilding), and as for curves, the stack laminating looks bulletproof, but an awful lot of work, absent a cnc. My vote would go for making your braces the permanent form for laminating two or three layers of bending ply, with titebond III, a narrow crown air stapler, and a paint roller for gluing the laminations. And watch how tight of radius your trying to bend, I've had my share of glue up madness, when the wood won't behave, the glue is drying, the clamps are all wrong somehow....

For curves, I like to draw them in a vector illustration program, and print them out fullsize for templates, not just for construction ease, but it is easier to get a curve that will bend naturally.

I will be interested in watching your progress.

[mrstampe]

Hey michael, that's a great looking speaker!

I think I'm leaning toward the Nat P Wave and possibly done in verticle polylam layout. In that case, the finish would be polyurethane over BB verticle layers on the wavy sides and a nice complementary veneer on the baffle. I just wonder if all of those verticle wavy lines would accentuate the curves or be too distracting? If I'm not going to see the polylam layers, I may opt for one of the other methods.

Rough dimensions would be as follows: H40" x W10" x D12", curve wavelength 20" and amplitude 1/2" --> If the sidewall were a soundwave, that corresponds to a audio frequency of 675Hz! Also an internal volume of 56L before driver, bracing and port subtraction.

Also, a higher tune or even a sealed enclosure for the mains may be easier to mate with that SDX15 sub in the planning stages. Any suggestions as to how best to tune and cross mains to the sub?

Thanks for all of the advice!