[Ron]

 Over the past few months I have built several pairs of Neo 2X speakers. Following the construction of each I tried different combinations of internal damping material to determine what sounded best. After much trial and error,
I found the following sound damping treatment to work very well for the Neo 2X (at least to my ears it does):

1. Line the sides,top,bottom,and back with No-Rez. Available from GR Research.

2. Loosely fill the back half of the enclosure top to bottom with Acousta-Stuf. Be sure to tease it out before putting it inside the enclosure. Available from Parts-Express in 1 lb bags.

 In comparsion to Dacron Poly Fil material,the Acousta-Stuf material deepens the  bass, provides a cleaner midrange, and improves the dynamic extension of the speakers.  There may be other sound damping treatments combinations that work just as well or better. What I am posting hear is only a helpful suggestion to others who may be building or already built the Neo 2X.

[Nick77]

I used the acousta-stuff product also in my ob/7 project along with no-rez and very pleased with results. I will definately use it for my future projects as well. Thanks for sharing your comparisions, you have comfirmed my suspicions vs poly-fill.

[corndog71]

technically, Acousta-Stuff IS poly-fill. It's density is a bit different from the cheaper and more readily available poly-fill you can find at craft stores but it's still just 100% polyester fiber.  Personally, I think it's overpriced.  The stuff I can buy at Joann Fabrics is so similar it's not even funny and I can get 2 pounds for less than $10.  I've used both and can't say I can tell a difference.

[Ron]

 Acousta-Stuf is not the same as Poly-Fil. Acousta-Stuf is a crumpled nylon polyamide material made of large tri-lobal fibers. Poly-Fil is made of small round Dacron fibers. Acousta-Stuf being more dense than Poly-Fil has better acoustical sound absorption properties. Actually, the acoustical properties of Acousta-Stuf are very similar to long fiber wool,but is better in that it doesn't settle over time or have to be sprayed with moth proofing.

[corndog71]

I stand corrected regarding the properties of Acousta-Stuf.

Nevertheless, the 100% polyester fiber works just as well in my experience and it's cheaper.

[RogerB]

Ron,  I followed your recipe to the "T" when I built my N2X's and could not be more pleased with them.  With one exception....I didn't put No Rez on the bottom of the cabinets as the crossovers were mounted there. 

Do you think I should take the crossovers out and put the No Rez on the bottom of the cabinets?  Do you think the difference in sound would warrant the effort?  Like I said, these things are incredible as is!

Roger

[S Clark]

Pull the woofers, lay a double layer of carpet padding over the crossover, seal it up and listen.  If you like what you hear, order some No Rez and make it permanent. The carpet pad isn't as good as No Rez, but it will tell you if there is enough difference to warrant pulling the crossovers. 

[Ron]

Roger

 At the beginning of this topic thread I did say to cover the top and bottom with No-Rez which is in error. In my opinion you don't need to cover the bottom with No-Rez. I did experiment with covering the  crossover with carpet felt and with 5/8" acoustical foam. To my ears they each did make a slight improvement,but I ended using only Acousta-Stuf as I described in the beginning  and not covering the top of the crossover. I personnally like the sound  best just using the Acousta-Stuf. You might what to experiment with covering your crossover to see if you like it better or just leave it like it is. Sorry for the mistake.

Ron

[RogerB]

Ron, I did put a good bit of Acoust Stuf over the crossovers and then filled the remainder of the cabinets per your instructions.  I'm pleased with the sound.  Someday if I get the time and motivation I may experiment as you and Scott have done.  As for now I'm just stunned at how beautiful these speakers sound every time I play them.  I picked up the Beatles new remaster of Abbey Road the other day and it just sounds like magic on the N2X's!  I had tears in my eyes by the time Golden Slumbers came on!

Didn't mean to ramble, but, the the way these speakers present the music...well..., it can have that effect on a guy.

Thanks Ron,

Roger

[Ron]

Roger

 I think that using Acousta Stuf over the crossover is just as effective as a piece of carpet felt or acoustical foam. Mine too have Acousta-Stuf over the crossover just like yours. Works just fine.You still might want to eventually experiment. Your opinion regarding the sound quality of the Neo 2X is the same as mine. They are simply wonderful sounding speakers. With clean,high quality electronics and a well recorded program source they can sound very realistic and emotional.
Really enjoy building the Neo 2x's. Just sold my second pair yesterday. Plan to start building either a third pair of Neo 2X's or possibly a pair of Neo 1X's within the next few weeks.

Ron

[RogerB]

Ron,  congrats on the sell of your 2nd pair of N2X's!!  With the quality of your work there will be many more to come!

One advantage I found with using Acousti Stuf over the crossovers was it was much easier to get it down on the crossovers between all the wires.  Putting a piece of padding or No Rez over the crossovers with all the wires would have been more difficult for me.  YMMV

Roger

[The Ninja]

Yesterday I was trying out some new mounting methods for networks.

I ripped off the foam layer leaving just the damping layer of NoRez and installed the network over that.

Still need to compare to a 'regular pair' to determine the effect...

Sean

Ron,  I followed your recipe to the "T" when I built my N2X's and could not be more pleased with them.  With one exception....I didn't put No Rez on the bottom of the cabinets as the crossovers were mounted there. 

Do you think I should take the crossovers out and put the No Rez on the bottom of the cabinets?  Do you think the difference in sound would warrant the effort?  Like I said, these things are incredible as is!

Roger

[corndog71]

I haven't completely figured out how I'm going to do my crossovers for my pair of x-cs'.

I moved one of them outside of the cabinet where it's currently hanging. 



At first I thought using some poster putty would be good to keep it from flopping around but then I felt the vibrations of the working speaker being transmitted directly to the caps.  I had a little chunk of norez handy and thought maybe that would help.  So I took off the putty and without removing the backing from the adhesive just wedged it between the board and the cabinet.  It diminished the vibration felt in the caps almost completely. 

I'm also considering just replacing the terminal cup with a piece of mdf with a speakon connector.  I don't know.  I'm torn in a few different ways.  I really like the potted crossover idea but at the same time would prefer to be able to tweak it.

So many choices.