Tang Band 5.25" Neo sub complete *PIC*

[gregrueff]

I finally figured out how to post pictures!

So I think I messed up the stain on the veneer pretty bad...It should be beautiful cherry stained a tastefully dark red- but you can see how well that worked out. Contact cement will be avoided in the future as well.

The high gloss "wanna-be piano" black worked out pretty well though (I think.) It looks nice in person. Piano black, or something close to it, isn't nearly as hard as everyone makes it out to sound. You just need to have patience to give it all the necessary coats of paint.

That mounting ring is something I've been wanting to try for some time now. It sandwiches the driver between it and the first layer of baffle (double thick.) It has a 3/8" roundover (all .5" material) creating almost a very shallow horn throat.

I've run basic low frequency sweeps just from script in Matlab to "listen" to the frequency response. My primitive hearing test reveals a relatively smooth response down to around 35-40Hz with expected boosts at frequencies caused by room dimensions and modes.

I can't get this idea out of my head though that it sounds "hollow" or "boomy." I have absolutely no evidence to back this up, but even for a sub this small I think .5" MDF is insufficient- and I braced it pretty darn well internally with .5" plywood and Sonic Barrier and Acousta Stuf. It sounds like the enclosure is resonating and coloring the sound.

Lessons learned.

I must say, I'm pretty psyched that my first real project (from design to finish) worked so well.

[christianb]

Looks great!

What method did you use on the "piano black"?

[tomzarbo]

Greg,
that's really a beautiful thing you have made. I'm sure the picture doesn't do the stain justice. That trim ring looks great, it must have been a lot of work - but it's a real nice touch.
By the way, I have a smallish 10" x 10" x 10" box with the 6.5 Tang neo with a 1-3/4" port and at full boogie I can feel slight tingles in the box. I used 3/4" MDF on it! Those little things do some thumpin' don't they?

Beautiful work, I'm almost inspired to get myself in the basement and do something myself. I do have a few of those 5.25" Tang subs just waiting to be used.
TomZ

[gregrueff]

> Looks great!

> What method did you use on the "piano
> black"?

Thanks!

Once the surface was smooth (I used wood filler and sandpaper to fix any minor blemishes.) I proceeded with the primer. RUST-OLEUM American Accents Oil-Based primer from Home Depot. Probably around 4-6 coats. Sometimes sanding inbetween, sometimes not- see below. The trick was to get a thick enough layer that light sanding wouldn't expose bare wood. Then at least two coats of High Gloss Ultra Enamel Black (Or color of your choice.) After the last coat, which was very thin, I didn't sand. (I know this is where people start going at it with steel wool, but I didn't think it necessary.)

I bought about $20 worth of sandpaper from 100 up to 600 grit. I worked my way up until my primer felt smooth, and I mean smooth. I was using 600 on the primer before I even got to the black.

Really not that hard, just time consuming.

[gregrueff]

Thanks!
Yeah, I think I'll try the 6.5 next time- maybe in a sealed enclosure.

They need some real bracing!

> Greg,
> that's really a beautiful thing you have
> made. I'm sure the picture doesn't do the
> stain justice. That trim ring looks great,
> it must have been a lot of work - but it's a
> real nice touch.
> By the way, I have a smallish 10" x
> 10" x 10" box with the 6.5 Tang
> neo with a 1-3/4" port and at full
> boogie I can feel slight tingles in the box.
> I used 3/4" MDF on it! Those little
> things do some thumpin' don't they?

> Beautiful work, I'm almost inspired to get
> myself in the basement and do something
> myself. I do have a few of those 5.25"
> Tang subs just waiting to be used.
> TomZ

[wingnut]

Would you mind sharing the plans? I've got several of these drivers sitting around too! Slots are new for me. What did you use for the cosmetic ring? Like Tom said, really nice touch. May I shoot you an email?

Funny, I built an open-back oak entertainment center just like the one in the picture. Mine has two cubbies in the middle and three on the bottom (same as on top).

Toby

[gregrueff]

It would be my honor to share the plans.

You don't happen to have Alibre 3-D Modeling do you? I have it modeled in that. I actually signed up for a trial version of the software for free just to design this. You or anyone else might be able to do the same, although they never stop bugging you to buy.

I have pictures of the whole build~ 50 pics.
Tomorrow I'll upload them all to photobucket.
You can email me too:
<A HREF="mailto:greg.rueff@gmail.com">greg.rueff@gmai l.com</A>

The cosmetic ring is 0.5" plywood. Kind of a pain to make:
1. Cut outside diameter
2. Cut inside diameter
3. Route roundover on inside diameter
4. Route roundover on outside diameter
5. Figure out tricky way to drill holes in correct spot and countersink them into the roundover (the business)

The slot sure looks nice to me. It makes the cabinet about twice as hard to build. It also allows the port to be over 18.5" long (since it's so large.) My theory is sub-par, but it's almost a transmission line.

> Would you mind sharing the plans? I've got
> several of these drivers sitting around too!
> Slots are new for me. What did you use for
> the cosmetic ring? Like Tom said, really
> nice touch. May I shoot you an email?

> Funny, I built an open-back oak
> entertainment center just like the one in
> the picture. Mine has two cubbies in the
> middle and three on the bottom (same as on
> top).

> Toby

[donparsons]

Really nice project Greg. A lot of nice touches. The piano black is a lot more work when you choose to do all the sides. I like the ring around the driver, the slot port and the spikes are a nice touch also.

Good work.

[Wolf]

> Thanks!
> Yeah, I think I'll try the 6.5 next time-
> maybe in a sealed enclosure.

That's not a good idea. Any form of extension these have will be nuked. Since the Fs is about 35, you won't get much below 40Hz, and it can reach to 18.5Hz in an oversized vented box. flared-2" minimum diameter port is a requirement.

> They need some real bracing!

I agree.
Later,
Wolf

[Wolf]

I used a 2.5" diameter, 20.5" long. Enclosure is a 12" diameter Sono, about 19" long internally. Extension to 20Hz, with 40W input, doesn't exceed Xmax all the way down. It sounds good too!
Later,
Wolf

[garys]

[marlowe]

Great looking sub!! Nice design and execution. I like the mounting ring and rounded slot port. Work to be proud of. You seem like someone who is not only interested in functionality but also art and aesthetics. Awesome for a first time design to finish project.

[gregrueff]

Provided Link: The Build


Thanks to everyone for all the kind words. Here is what the inside looks like.

All the build pictures have been uploaded to Photobucket. I'd be happy to answer any questions about the build.

[gregrueff]

Is this considered an extended bass shelf alignment, or a transmission line? How do you extend the frequency response below the f3 of the driver? One of my goals in this project was to get the absolute lowest f3 possible for such a small driver.

My research has not led me to any information on this.

> I used a 2.5" diameter, 20.5"
> long. Enclosure is a 12" diameter Sono,
> about 19" long internally. Extension to
> 20Hz, with 40W input, doesn't exceed Xmax
> all the way down. It sounds good too!
> Later,
> Wolf

[wingnut]

[Wolf]

> Is this considered an extended bass shelf
> alignment, or a transmission line? How do
> you extend the frequency response below the
> f3 of the driver? One of my goals in this
> project was to get the absolute lowest f3
> possible for such a small driver.

Been there, done that! =-)

> My research has not led me to any
> information on this.

Yes- It's an EBS. All three of the Neo-subs model this way. The 1363SA I have will extend to 17 Hz F3, in a 3.5ft^3 box, and I have this one complete. The 1139 will extend to 18.5 Hz.
Later,
Wolf

[gregrueff]

Wow! That's a pretty big box- a whole lot bigger than mine.

Are there any resources you could point me towards which describe the theory or how to model this alignment?

> Yes- It's an EBS. All three of the Neo-subs
> model this way. The 1363SA I have will
> extend to 17 Hz F3, in a 3.5ft^3 box, and I
> have this one complete. The 1139 will extend
> to 18.5 Hz.
> Later,
> Wolf

[Wolf]

> Wow! That's a pretty big box- a whole lot
> bigger than mine.

But it's the 8" in that box, 4" port x 28.5" long.

> Are there any resources you could point me
> towards which describe the theory or how to
> model this alignment?

Do you use Unibox or WinISD? etc? I use Unibox, as it can model the xmax issue. You enter the params for teh driver, and play around until the numbers look right. Usually, the trough in the middle of the EBS design wil be about 3dB in amplitude. I'm at 4.5dB in the 1363 design, but I'm around 3dB in the other 2. The 1138 is in 35.2 ltrs, with a 2.5" diameter, x 20.5" long vent.

What you want is a graph in a shallow-M shape. A peak before bottom rolloff about the same level as the broader upper-peak, and about 3dB in the trough. Try to keep xmax in check, and the box can increase in size to reduce the port length. Generally these are characterized as over-sized, low-tuned (below Fs normally), large-diameter ported, etc.
Good luck!
Later,
Wolf

[gregrueff]

[zach_t]

Nice looking build, I like the ring over the driver.

I just bought 4 of those on sale and will be using 2 of them in the bottom of a compact 3-way. Not sue how I want to treat the interface to the box. I was thinking of recessing into the 1.5" baffle and chamfering around them. The closeout ring is another option.