Natalie P and sub question

[elessar]

Due to space limitations i really don't want to make the tower version so this leaves me with a sub.

Well I'm new to speaker building and have read a bunch about porting and sealed.
Sealed "theoretically" has better group delay response and impedance phase.
The official version of the Natalie P is ported but many people that build it for use with subs make it sealed, is there a good reason for this? (yes i can seen the different frequency responses and such in WinISD).

For subwoofers, is there a suggested build for them? What is the general opinion of ESP's p48 (sub equalization thing making it linear, one worry is distortion with such high excursion)

http://sound.au.com/secure/p48a-assemble.htm

i generally listen to music with some movies.
I want the bass to be clean, not boomy and connected with the rest of the sound.

for comparison i have been using realistic nova15 on an ancient magnavox 93-02-00 tube amp. I already have the ESP p101 amp made and i'm still looking at speakers:roll:.

[linguistisch]

Not sure if this helps but I built subwoofers into my RS180/RS28A towers. I didn't want to rely on the MTM alone for bass (mine are music only).

Most suggested building a separate subwoofer cab and putting it somewhere else in the room for room nodes but I'm making towers right now similar to the older Polk LSi25. Going to cross the MTM higher now, let the stubs do the heavy lifting.

I have a build thread going on PE but I'll probably port it over here for more suggestions.

[PewterTA]

If you going to build your own sub, I would definitely recommend not having it ported. You want a sealed enclosured sub. Size and power is really more up to you and what you want/need. There's a bunch of kits over at Parts Express that will get you good sound. There's also manufacturers like SVS and HSU that make very nice subs at almost the same price point as doing it yourself.... So that's something to consider as well.

My other suggestion and it's purely from listening to many systems with subs... is a dual sub setup is much better for music. Especially when the subs are located in proximity of the speakers. It just seems to balance everything out and get rid of the nulls a lot better than trying to make a single sub do it all. Plus depending on where you cross things over, for me, it has to be low so I can't locate the sub and have it stick out like a sore thumb...which means your mains have to go decently low to compensate.

[JonMarsh]

If you going to build your own sub, I would definitely recommend not having it ported. You want a sealed enclosured sub. Size and power is really more up to you and what you want/need. There's a bunch of kits over at Parts Express that will get you good sound. There's also manufacturers like SVS and HSU that make very nice subs at almost the same price point as doing it yourself.... So that's something to consider as well.

My other suggestion and it's purely from listening to many systems with subs... is a dual sub setup is much better for music. Especially when the subs are located in proximity of the speakers. It just seems to balance everything out and get rid of the nulls a lot better than trying to make a single sub do it all. Plus depending on where you cross things over, for me, it has to be low so I can't locate the sub and have it stick out like a sore thumb...which means your mains have to go decently low to compensate.

+1 on everything he said...

Close location with the mains and dual subs gives you more flexibility about the crossover points; you can run higher and take more work off the NatP's. One possibility to consider is the Seas LROY 10" (actually, I recommend the special dipole version- it's large signal characteristics are better), in a sealed box. Ported has much more hangover and less definition- suggest using Unibox to model any box and driver configuration you might be considering. I suppose someday I should come up with a firm recommendation for this... will try to put my thinking cap on about this topic sometime in the next few weeks. Got a lot going on right now at work and ongoing projects (Isiris crossover finalization, new crossover build, final cabinet assembly) and music server.

[wkhanna]

I currently use 2 HSU subs positioned close to both NatP’s (ported towers).
I am V pleased with the results for ‘music-only’.

I would expect better results with sealed subs, but I got these matching subs used at a price that I could not pass on.
I am sure I would get even better performance with sealed units.

I am still experimenting with the ports sealed vs open on the NatP’s, along with the xo settings. I will try to get some fq sweeps posted asap.
My pre-amp has duel output terminals, so my subs are hooked up in true stereo & I am sure this helps me achieve a decent level of smooth xo transition that could be a little higher than would otherwise be possible.

In a music application, for my personal listening habits, I do not need massive SPL, just natural, realistic sound in the mid-low (25 – 70 Hz) range since there just is not much signal produced by most acoustic instruments in the low region. Other than some big pipe organ music, you will not use the lower end of the subs much.

Eventually I will have two smallish (10”) sealed subs but for now, I am quite satisfied.
One thing is for sure, having the subs truly opens up the music, allowing all the information on the recording to be heard in your listening room. It adds an entire dimension to the music that otherwise you never knew existed. Even with small scale acoustic Jazz, the added response is clearly evident as string bass rhythms are flushed & fleshed out, making listening to old favorites seam like hearing them for the first time. The same is true for classical, there is a lot information in the mid-low region that is quite evident at live venues. Having that little boost in this region to balance out the whole really adds a realistic dimension to the music.

[fbov]

Due to space limitations i really don't want to make the tower version so this leaves me with a sub....

Rules are not so cut and dried.

True, I built 65L towers tuned to 31Hz with shielded drivers. But I also built 20L sealed bookshelves with unshielded drivers. These are extremes on a continuum, and there's reason to believe you can find bass in less than 65L!


If you can't live with 65L, how about 42L (1.5 cu ft)? Here's a comparison with the 65L tower.
F3 rises from 32Hz to 38Hz
F10 rises from 24Hz to 29Hz.

For conventional music, 40Hz is the target for F3 and you beat that. Add some room gain and you'll reach infrasonic frequencies...

HAve fun,
Frank

[speedle]

If you check out my build thread for my Natalie P pair you can see the sealed 1 cube mtm on top of the 3 cubic foot bass bin. I cross the tops over at 70 hz with those little things PE sells, f something or other, then the bass is driven by the 300 watt bash amp, set to about 100 hz. A little finicky to set up at first, but very satisfying in the long run.

[elessar]

Dual subs sounds like a good idea, but I think i will first get the mains and then get the subs. I do realize that subs will take more room than larger mains but it would be easier to change the orientation of the subs and mains to fit the current room and a different room.

I do like the idea of using the PE 1ft^3 cabinets for the ease of construction. (get the speakers sooner) But if there is some significant gain from other sizes ...

What is the general opinion of sealed vs ported for the Natalie-P? I think I saw somewhere that some builds had a port that was able to be sealed. I only saw it in passing but is there a good method of doing this?

[elessar]

Thank you fbov for basically saying i should look at other options. My problem with space for towers is because of height.

I do think it can be fun to build my own cabinets. I was thinking that i could make it wider by making the front be 4 layers of plywood thick and all with a 45 angle. (the inside 2 layers probably having a large cut-out. this would allow the cabinet to be 13.5" wide (internal 1ft allowing 1ft deep and 2ft high to reach 2ft^3) and not have the distortion of the wide front baffle. or i could be completely wrong.

Since I'm looking at building cabinets now there is a question of materials. I do like the look of wood and don't really like the idea of using veneer so i don't think i really want to use MDF. The Plyboo seems rather expensive. I have notices quite a bit of mention of Baltic Birch but was wondering if there was also other suggested wood/plywood i do like the idea of plywood.

[johngalt47]

I have two subs that I have used with a variety of mains. The one that sounds the best with music is a Dayton
RSS315HF-8 in a sealed enclosure. I also have a L26ROY with the Seas PR recommended to go with it. Right now
I am using it with a pair of Overnight Sensations for computer speakers. It is great for that purpose.

[fbov]

Box width is a design variable, and disguising it as deep chamfers won't do what you expect. Simply put, the transition from 30' waves to 1/3' waves is so broad, the low end won't notice the chamfer, the high end won't notice the chamfer, you'll just distort what's inbetween away from what Evil Twin used to develop the design. Height and depth are your friends when you want to vary box volume. If you vary width, go in-wall/flush mount (infinite width).

Conversely, a 1 cu ft ported box becomes sealed with a sock in the port. If you're new to this, your ears have some learning to do. Go with the PE box and learn something. If what you learn leads to building your own, larger boxes, consider the cost of the lesson - time spent building speakers / cost of buying and building = a lot less than going to the movies!

HAve fun,
Frank

[speedle]

Making a Natalie P cabinet that wide will get you a speaker that doesn't sound anything like what the rest of us have built. I haven't done the math, but you'll get a heck of a bump/dip somewhere and you're gonna know it.

[elessar]

ok, just thought an angled front might be a work around but I guess not.

TY all

[fbov]

An angled front on a wider box will "work" but it will not be optimized for this crossover design.

Building proven designs has one drawback in that you need to understand the designer's constraints - what assumptions did he use in development? In any free-standing speaker, baffle width is a design variable; you have to pick a value to start the design. Change baffle width and you have to re-optimize the crossover. Since crossover design is a bit of an art, we just build it like the designer intended!

HAve fun,
Frnak

[elessar]

Well here is a picture of my old router as i start cutting the front baffle on the PE cabinets. (the slowness of doing projects still surprises me :roll: )



Does the tweeter need to be blocked and sealed off including the wires to it? The tweeter seems to be well sealed on its own, but i see everyone blocking it off but never showing how they deal with the wires. Are the wires just glued over where they enter?

[wkhanna]

Does the tweeter need to be blocked and sealed off including the wires to it?

Yes

Are the wires just glued over where they enter?

That is what I did.
Just a dab of silicone.

Great to see you getting started.
You have now made it past the hardest part!

[elessar]

Well had an annoying problem. I fully made the first and it sounded good then i completed the second but it was rather missing on the low end. My first though was what did i do wrong. I searched over the x-over and didn't find any problems triple-checked all the wires. Eventually narrowed it down to the actual woofers. When i swapped them around i found that one was defective on a hunch i tried reversing the polarity going to it and that fixed it. with the polarity swapped on the one woofer they all sounded the same. Is it at-all common to have the polarity swapped from the marking (and physically from the other 3)? Could the be just an indication of some other failure and i should get it replaced? I would rather not, they do sound great.

[JonMarsh]

Well, that is an odd thing to come across with reversed polarity- is it the polarity markers on the drivers that are reversed, or you are actually hooking them up to different terminals?

OTOH, I'd say that since you've fixed it, I'd leave well enough alone- the functionality is probably fine otherwise. When thou mentioned in your post that one was missing in the low end, the first thing I was going to suggest was double checking the driver polarity. You got that done just fine- that's part of what DIY can be about, as you're chief builder, QA. and troubleshooter!

[elessar]

all the terminals look the same the red mark is all on the same side. If the one had that backwards it would be more understandable.

Again thank you for your designs and help. They do sound great.