My plans for my NSBs - feel free to make comments!

[Spasticteapot]

I've ordered 32 NSB's - WOOT!

Now, to build something.

Project 1: MTMs
I'm still a bit of a newbie (I've yet to make a pair of speakers that sounds decent), and want to go with something traditional - in this case, a nice, simple MTM, to which I hope to add a cheapie subwoofer driver later. (The enclosure will likely have a divider - the two are totally seperate.)

You can see what I'm going for with the "Ultra-budget HT" speaker design (UBHT) seen on the Parts Express project showcase, and cosmetically differing cousin, the Jessicas.

http://www.partsexpress.com/projects...ubht/ubht.html

While the Meiloon tweeter used is not availible, ApexJr has a few nice tweeters, including the Sonace soft-dome at all of $5, and the classic "Apexjr tweeter" at $1 each.

http://apexjr.com/speakerstuff.html

While the tweeter is obviously going to be different, I'm hoping to re-use the UBHT crossover, at least the bass EQ section. However, I'd like to see if I could roll it off at about 80hz for use with a subwoofer - preferably, a cheap one. Were this an optional modification (I.E; able to be switched in and out), that would be dandy.




2. 2-way PVC TL

This is an excercise in simplicty - load the driver in the end of some PVC pipe, with a 45 or 90 degree elbow, forming a transmission line that looks a bit like a cane. Add a small plywood baffle to the end, and mount the woofer and tweeter. I'm not quite sure what diameter of pipe to use, though.

Here is a similar project:
http://melhuish.org/audio/DIYTQ7.html

My only real modifications would be to use pipe with thicker walls, and add a larger baffle with a tweeter on it. (And a crossover, of course.)

3. Line arrays.

I might have to go buy more drivers for this, but line arrays seem like a way to get the most out of these inexpensive drivers. I'm tempted to splurge and go for some cheapie planar tweeters like the Dayton PT2B, though I think I'll try the $1 ApexJr tweeter first.

Perhaps 7-9 NSB's a side with the same number of "Apexjr" tweeters, or two PT2Bs?

For the actual physical design, I think I'll go with an open baffle - I've heard that the NSBs work well that way, though not surprisingly, bass performance is awful past 100hz. Of course, a seperate enclosed cabinet for the woofer(s) will be needed - I figure I'll use an 8" silver flute woofer.

Here's a similar project:
http://www.partsexpress.com/projects...ine-array2.jpg

4. Driver-in-a-bottle rear-channel speaker.

I want to stick a driver in the end of an acrylic bottle, and use it as a surround. It seems to work well enough for TangBand drivers - I figure that these should work okay, too.

These are obviously going to be wall-mounted.

Questions:

1. I'm going to try to model these in WinISD. Any tips?

2. What mods are usually done to these drivers?

3. What do you think I should do?

[joe carrow]

Where were you even able to find any NSBs? I think it's been nearly a year since Parts Express had them in stock.

These drivers are simply awesome for the price. I purchased a small number of them when I was just getting into the hobby, and they were fun to experiment with. I though that they sounded rather good in an open baffle dipole, but if you want them to get even remotely loud you'll need to build arrays.

I had a 250 watt amplifier that I used to drive one of these in an open baffle once, and I attempted to blow the driver. The driver took some extreme input, but thermal compression set in and the output really wasn't very loud. Surprisingly, the driver lasted for over five minutes in this condition before I thought better of it and turned it off. I didn't want to melt or burn a coil and definitely short the amp, although the whole experiment was probably kind of dumb.

I think you have the right idea using them in a 3-way line array; I don't think their output is acceptable even at 100 hz.

For mods, I added a phase plug, and it seemed to have a positive effect on subjective smoothness. I've also heard of people coating the cones with damar varnish, or puzzlecoat. It's a clear varnish that goes on thin and dries hard; you should be able to get it at an art supply store that does oil paints.

On a side note- I think that all of this stuff with the Dayton Reference series has kind of sidetracked a lot of entrants into the DIY audio hobby. It's just so economical to build an established design with these drivers that will rival the sound quality of commercial speakers far beyond the price of materials that a lot of forum participants (myself included) tend to steer the newest beginners toward the established projects and away from the super cheap experimentation.

I'd personally like to see more of these buyout drivers- another batch of usable 50 cent drivers opens up all kinds of experimentation, for example- something like this array from Yamaha:

Whatever you do, have fun with it!

[Spasticteapot]

Originally posted by joe carrow
Where were you even able to find any NSBs? I think it's been nearly a year since Parts Express had them in stock.

I bought some off a forum member. I paid a grand total of $64 shipped - not bad at all!

That said, if anyone else has any they'd like to get rid of, I've got a lot of projects in mind...and you can never have too many drivers.

[TerryO]

Here's a small project that sounded very good, especially for the price: I estimated less than $3.50 for the pair. That's drivers, terminal cups and wires, plus the MDF. The "cabinets" were actually spools used for strapping tape and were free.

http://theloniousbonk.smugmug.com/gallery/505390/1

Best Regards,
TerryO

[Spasticteapot]

Originally posted by TerryO
Here's a small project that sounded very good, especially for the price: I estimated less than $3.50 for the pair. That's drivers, terminal cups and wires, plus the MDF. The "cabinets" were actually spools used for strapping tape and were free.

http://theloniousbonk.smugmug.com/gallery/505390/1

Best Regards,
TerryO

No good for me, I'm afraid - I'm trying to avoid woodworking, as I'm really, really bad at it.

[bjorno]

What do you think I should do?

Build a long line array or...

b.

Picture 1(1)

[Spasticteapot]

Originally posted by bjorno


Build a long line array or...

b.

Picture 1(1)

What's wrong with a standard MTM?

[idaho]

If you dont mind sharing Pls? I know its been out of stock for a long time now at partsexpress.

Thanks!

[joe carrow]

Originally posted by Spasticteapot



What's wrong with a standard MTM?

Pairing a cheap tweeter with this cheap woofer necessitates a high crossover frequency- say, 3 khz, depending on the tweeter. High crossover frequencies cause lobing and interference if the drivers are too spaced out.

Using a better tweeter to take advantage of a lower frequency would kind of defeat the purpose of $0.50 woofers. If you're really sold on MTM, I'd recommend the $5 small flange neodymium 3/4" tweeter.

http://www.partsexpress.com/pe/showd...number=275-035

It's supposed to do fairly well (especially for the price) above 3.5 khz.

[Spasticteapot]

Originally posted by joe carrow


Pairing a cheap tweeter with this cheap woofer necessitates a high crossover frequency- say, 3 khz, depending on the tweeter. High crossover frequencies cause lobing and interference if the drivers are too spaced out.

Using a better tweeter to take advantage of a lower frequency would kind of defeat the purpose of $0.50 woofers. If you're really sold on MTM, I'd recommend the $5 small flange neodymium 3/4" tweeter.

http://www.partsexpress.com/pe/showd...number=275-035

It's supposed to do fairly well (especially for the price) above 3.5 khz.

The Sonance tweeter from ApexJr is another option that's supposed to be pretty good, and shipping is actually less. Then again, the ND20 is also very, very popular - $5/tweeter is an amount I can afford!

I also live within a short distance of Madisound. What about the Sinar Baja tweeter they have on sale?

http://www.madisound.com/cgi-bin/ind....24231&pid=120