The Neon's

[Mike Burke]

To start off with I am a novice at speaker building. I have been building small desk tops for a couple years from other peoples designs. I was a little hesitant to post a build thread because of all the other great builds here but I really wanted to share these Neon's with you.

I was wanting to build a small boxed speaker for my fishing boat so I contacted Scott Sehlin about designing a small speaker that would fit in the area that I had in my boat and with drivers and parts Scott and I had in our stock pile of parts.

Scott came up with The Neon's

A small cabinet speaker using the Aura NS3 193 8A 3” 8 Ohm driver and Dayton Audio ND16FA 6 5/8” soft dome Neodymium tweeter. Along with cross over and a 1” port the Neon's were born and I went to work constructing them. Scott suggested this box size.....

5” wide x 9” tall x 6” deep with 1/2” material and a 1” x 4” port. Dimensions are external

Drivers are centered horizontally. The center of the tweeter hole is 1” down from the top and the center of the woofer is 4” down from the top.

I started with the port in the front but after listening to them for a couple days I decided to move it to the rear. With the front port location I thought they sounded bright and forward. So in an attempt to spread the sound out and smoother I filled the hole in the front and placed the port in the rear. I thought they sounded smother and was happy with the adjustment.


I used 1/2” MDF for my cabinets. This stuff is easy to work with, inexpensive and after I coat it with sanding sealer, sandable primer and a couple coats of DuraTex they are pretty sturdy cabinets. I find that the sanding sealer transforms this otherwise soft material into a hard durable product.

So after listening to the Neon's for a couple weeks I am amazed. I have been listening to them in my shop with a SMSL Q5 Pro and am surprised with the bass they product. They sound great to me and I'm very pleased with the way they came together. I'm not so sure I will be putting these in my boat now beings they sound so good sitting in my shop.

Awesome job Scott and thanks for all your time and help.

[ceiol]

looks great -- nice design!

[andykriech]

Very nice, though the name suggests a different finish...;-)

[Brian Steele]

Nice build....!

Some interesting design decisions seem to have been in the x-over. Were those frequency response graphs generated from measurements taken of the drivers in the box? There's a fairly broad "hump" in the response in an area where our ears are pretty sensitive (2 kHz to 6 kHz). That might explain the "bright and forward" sound that you heard, as the the frequencies emerging from the vent are likely much lower in the spectrum and therefore won't affect the response in that sensitive region. From the looks of it, that "bright and forward" sound might be due to the tweeter not being rolled off fast enough after the xover point, and the woofer being rolled off slightly too high.

If you have access to the FRD and ZMA files that were used in that x-over design, I wouldn't mind having a look to see what I could come up with.

FWIW, I find XSim a great tool for x-over design, but it would be much better if it allowed for the easy addition of target response curves, rather than leaving it up to the user to "eyeball" everything.

[scottsehlin]

Those are driver measurements made in a similar box. I've been through a dozen or so iterations with this crossover and there is a bit more going on here than is shown via the crossover sim. The Aura NS3 (or the Dayton ND-90) models to a very large vented box size, so any tuning one can come up with in a box appropriate for a 3" driver is going to be rather peaky. When I had a flatter response through the 2-6 kHz region, the tuning sounded rather boomy. The preferred remedy would be to raise the level from the lower midrange through the treble region, but I couldn't find an approach that did that without requiring too many crossover components for the small box. This design is a balancing act more than an attempt at perfection, but has some unique capabilities given the reasonable size/cost.

[PWR RYD]

I have heard at least a half dozen or so of Scott's designs and I'm quite sure this one doesn't sound like that sim indicates it would. Dr. Scott knows his way around a xo and has good ears.... even though he has a strange flashlight fetish Or was that someone else?

[Brian Steele]

Those are driver measurements made in a similar box. I've been through a dozen or so iterations with this crossover and there is a bit more going on here than is shown via the crossover sim. The Aura NS3 (or the Dayton ND-90) models to a very large vented box size, so any tuning one can come up with in a box appropriate for a 3" driver is going to be rather peaky

Interesting. I wonder how it would to in a lossy vented box? Basically stuff the box full of polyester fiberfill as well as venting it. PE recommend a box that's about 4.25 L in volume tuned to 50 Hz, but some messing around in Hornresp for a few minutes suggests that going to 5L and stuffing the box and adjusting the tuning back 50 Hz pulls down the hump quite nicely.

[Brian Steele]

Ok, 5 L is a BIG box for a 3.5" driver (sigh).

Here's another attempt, 2.3L (net), tuned to 50 Hz (box heavily stuffed, and the "vent" stuffed 50%). Basically stuffed until Fb reaches 50 Hz. There's a small hump around 100 Hz. But might be workable. I've got another order with PE coming up - I might just add two of these drivers to see if a stuffed MLTL design with them would work well.

[Brian Steele]

BTW Mike, how did you achieve that finish on your speakers? It looks like Duratex, but a smoother finish.

[Mike Burke]

Hi Brian
The finish is Duratex. Applyed with the little foam roller that came with it. I just get a even coat and roll it until it looks good and let it dry.

When I contacted Scott I had a size limitation on the box size..so there was limit on the box size.

After listening to these for a few weeks they just keep sounding better.
As fare as the "bright " sound I had mentioned...some denium stuffing cut some of that down and helped the overall sound. And with them being in my boat that forward sound (even if its still there) will not be a bad thing in the open area of my boat.

[scottsehlin]

Denim lining/stuffing is the right way to go on these as it will give a similar effect to increasing the box volume (including lowering the port tuning). I am still planning to build the same boxes as Mike's so we can give more specific recommendations for the tuning. If there is a solution that settles down the peaking enough, it may be possible to lower the 2-6 kHz region a little, which will get closer to the Helium response curve and voicing. It's already fairly similar, but a little more forward in the even smaller prototype box I have the drivers and crossovers in now. I'm glad Mike posted this and has been willing to do some experimentation, as it is still somewhat a work in progress. His experiences and insights will influence the final design.

[Brian Steele]

Hi Brian
The finish is Duratex. Applyed with the little foam roller that came with it. I just get a even coat and roll it until it looks good and let it dry.

Hmm. That's the same stuff I use, and I use the same roller. but the resulting finish looks a little rougher. Oh well, I guess I'll have to experiment with it a bit more...

[djg]

Nice everything. Nice design, nice build thread, nice workmanship.

[ceiol]

Bass tuning by Brian Steele and XO by Scott Sehlin would make a killer combo!

I did something similar with the ND16FA-6 tweeter and the 4 ohm version of the Aura NS3 in a boombox


http://techtalk.parts-express.com/fo...pepper-boombox

I’m subscribing to this thread!

[Jake]

This project is right up my alley. I love the Ns3, shame the front port didn't work out. I much prefer the look. I'll be interested in future tweeks. Good work guys.