My build of ZaphAudio 2 cu.ft Dayton RSS 12" HF Sealed Sub

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My build of ZaphAudio 2 cu.ft Dayton RSS 12" HF Sealed Sub

Hi There! I'm new here, and many would say I'm a speaker noob. But despite not having done a speaker project before, I feel very comfortable with all kinds of tools and techniques, and I've built plenty of electronic projects and pieces of furniture, so I'm jumping in to build a sub for HT/music.

I've been lurking here and there for months, planning My First DIY Project (tm). After much research and thought, and a little advice from PE Techs, I've landed on using the Dayton Reference Series HF 12" driver, and the 500 W Dayton plate amp to build the Zaph Audio 2 cu. ft. sealed sub. I originally wanted to try the Drake, but I was seeking a little lower extension, so wound up here.

And while I'm comfortable plunging in, I do have questions. I'm carefully adapting the design to use 1" MDF as in the Drake, and while comparing that to the pictures in the archive zip file, something is bothering me...

If you look at this picture, there clearly appears to be an MDF panel on the inside back, sealing off the amp cavity from the rest of the sub. The speaker wires are poking through it. This makes some sense to me, especially considering the Drake design.

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However, I'm confused by the amp area in the schematic (the screenshot of the .pdf below). In the rear view, there appears to be a panel there that closes it off. But in the side view, there doesn't seem to be a piece that will seal the amp housing from the rest of the cabinet. For one thing, the depth of the amp housing (4.5") plus the back panel (3/4") appears to be the same as the depth of the amp itself (5 1/4"), allowing no room for a 3/4" panel to seal it off.

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Is it necessary to seal the amp section off from the rest of the cabinet, as in the Drake design? If not, why does that picture seem to have it sealed off? And further, if it is sealed, that doesn't seem to be taken into account in the box volume calculations. Is this right?

John Krutke doesn't seem to be accepting email right now, and I realize I'm probably making too big a deal of this, but any insight you have would be appreciated. Thanks in advance!

Choots
 
Yes, the closed area would need to be accounted for in terms of volume. Yes, if possible, it's good to keep it closed. If I were you, I'd close it, as you're doing one heck of a build on it, it seems. No sense wimping out now! A sealed box, fortunately, doesn't tend to be as volume-critical. I'd just close it up, and finish as normal.
 
Should I adjust the design?

Thanks Badman. I agree that closing it off is the best idea, but I'm trying to decide whether I need to go to the trouble of adjusting the internal volume to compensate for the additional panel required.

Based on the picture of the sub and the design, I believe there's a minor error here; there is supposed to be a panel that seals of the amp cavity there and it isn't accounted for in the box volume calculations. Also, I believe I've found another couple minor errors resulting in a difference in the box volume:

1) As discussed, the amp cavity cover panel shown in the picture is missing from the design diagram and volume calcs. This equates to approximately 0.06 cu ft.

2) The front baffle brace volume calc is missing. The volume of the 1 1/2" x 3/4" pieces at the front of the cabinet equate to approximately 0.04 cu ft.

3) According to PE Tech help, the driver volume is 0.134 cu ft., not 0.06 cu ft.

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This means that the real box volume is approximately 1.89 cu ft. instead of 2.07 cu ft.

This equates to almost a net 10% reduction in box volume. What effect will that have? Will I lose some low end extension if I don't adjust for this?

Or am I being too analytical about all this?

Thanks,
Choots
 
Re: Should I adjust the design?

Choots said:
John Krutke doesn't seem to be accepting email right now, and I realize I'm probably making too big a deal of this, but any insight you have would be appreciated

Yes, I currently don't accept emails. Whenever I post my email address, the floodgates open and I'd spend my entire evening answering emails. (or ignoring them) But, if I see something on a forum and I have a moment to reply, I sometimes do. (poof, here I am)


Choots said:
1) As discussed, the amp cavity cover panel shown in the picture is missing from the design diagram and volume calcs. This equates to approximately 0.06 cu ft.

2) The front baffle brace volume calc is missing. The volume of the 1 1/2" x 3/4" pieces at the front of the cabinet equate to approximately 0.04 cu ft.

3) According to PE Tech help, the driver volume is 0.134 cu ft., not 0.06 cu ft.

1)Good eye. Yes, there was a MDF square glued on top of the H-frame brace. Using those dimensions, the amp fits behind it sufficiently. This was an afterthought however. I thought I wouldn't need it, but the first time I fired it up, the amp rattled. (big alien fart in War of the Worlds when it comes out of the ground) The space it takes up is insignificant.

2)Also deemed insignificant.

3)when I calculate driver volume, I basically calculate a cone, cyclinder (for the magnet) and throw in a bit extra for the frame. But note however that a good portion of this driver's volume has to be added back in because the baffle is 1.5" thick. Some of the cone volume taken up is inside the baffle, not to mention the hole through the baffle adds a little more effective volume.

All that said, this kind of volume calculation is way overkill and I just do it because I am a perfectionist bordering on a compulsive obsessive disorder. (or so my wife says) All you really have to do is get close and it's a maximally flat alignment, and even if you're off high or low, the parametric EQ can compensate.

John

(poof, I'm gone.)

:D
 
Thanks for the help...

John,

I understand why you don't accept email... and I don't blame you! With your experience and designs out there, I'm sure there's quite alot of questions out there that get directed your way.

Thanks for taking the time to school a newbie on this... Obviously I too, lean to the obsessive regarding these types of calculations. I wondered about the how the driver volume calculations were affected by the baffle width, so that's interesting.

I guess I'll push ahead, and start making sawdust! I'll continue to use this thread to post my progress and results.

Thanks again,
Peter
 
Build progress update 1

Hey all... I've made some progress on my build:

Over the last two weekends, I
1) cut and laminated my 1/2" mdf pieces to create 1" thick oversized blanks for the sides.
2) cut out the braces and the amp cavity pieces
3) cut the side pieces to final size; I'm using miter joints all the way around, so this design had to be modified slightly for the joinery.

I also glued up the back panel with the amp cavity pieces and cutout the amp recess.

After a short delay I'm now planning the best way to glue up most of the cabinet, cut the driver opening, and complete it.

I'll post a few more pics tonight.

Peter
 
Build Progress 2

Hi all, I'm back, and I've had a fairly productive weekend...

Some say I'm way to OCD for most people, but I will admit to being an obsessive planner. I spent a long time thinking about the glue up of the subwoofer cabinet, figuring out the best clamping arrangement to allow me to do it 1) accurately and 2) without any help.

I'll remind you that the cabinet is mitered on every edge, so this makes the glue-up extra involved... The way MDF develops a fuzz on a cut edge makes it extra "grabby" so it doesn't always go together right. Add to that the fact that you need two hands to close a clamp, and I was envisioning having a very hard time getting six panels to go together right and not have a glue soaked mess...

I'm happy to report that I figured out what I think is the best way to do it.

Normally I wouldn't go into this detail, but since I spent so much time on the net trying to find details of construction for speaker building, I feel obligated to share my experiences. Here's my (reasonably) brief description of the process:

1) Beginning with three panels (back panel with Amp housing, bottom panel, and the top panel), dry fit them together. Set the Top and Bottom panels in place over the Back panel lying on its back. Clamping the top and bottom panels against the Amp housing braces creates the right 90 degree angles to avoid having to clamp up all panels at once.

2) Glue only one of these two panels along one edge (bottom to back, or top to back) and against the Amp housing braces. Clamp against both panels to get the best possible fit and confirm with accurate squares and measurements. When dry, glue the other panel the same way.

3) Now dry fit the rest of the panels to ensure they will fit properly. Once satisfied with the fit, glue only one of the two side panels along three edges (against the top, back, and bottom). Keep the remaining two panels in the glue-up (front baffle, and one side) dry to ensure they all fit properly. Use painters tape on the corners where three panels meet to prevent glue seepage from sticking. Use a couple pieces of tape around an edge as handles to pull the front panel out when dry. When dry glue the other side panel the same way.

4) Remove the front baffle, and seal the interior joints with polyurethane. Seal the amp housing joints the same way. Add the cabinet bracing.

Next on to the routing of the front baffle to accept the driver!

Stingray -
I've taken pictures most of the way through, but still have to convert them down to a smaller size, and host them so please bear with me...I'll get there.!! :)

Thanks,
Peter
 
Finally...Pics!

All right everyone... I promised pics and here they are. I've spent some time getting them hosted and posted... I've always wanted more details when searching for DIY projects on the web, and I like how-to's with lots of pics, so I hope I'm not boring you with my simple noob subwoofer cabinet build, but I wanted to document it as I go...

On to the pics!!


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Panels cut to rough size.
...cleanup that workbench! My design tweaks call for an 18.5" cube on the exterior, with 1" thick panels. Beefy!


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Laminating the panels and braces.
The panels are two 1/2" pieces of MDF glued up. I had only 3/4" lumber to work with to make braces, so had to laminate pieces together to make them 1.5" thick.


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More panel laminating.


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Panels cut to final size, with mitered edges.
I'm very happy with my table saw...once I ran a couple test cuts, I had a perfect miter joint. It does a great job.


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Gluing the amp housing to the back panel.
Prior to gluing, I used the table saw to cut up through the back panel, and finished up with a hand saw to cut the square opening for the amp cavity. The top and bottom of the H-brace will be glued against the top and bottom panels. This will make it much easier to align the miter joints and get good, square joinery.


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Panels ready for glue-up.
It took me a long time to figure out the best clamping arrangement, and alot of dryfitting, but it was worth it when you look at the final product...


Continued next...
Peter
 
More Pics ...

Back to the pics!


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Gluing the bottom panel to the back panel.
Here the back panel with amp housing is lying on it's back, with the panel that is to become the bottom of the sub facing to the right of the camera. The only glue is between these two panel edges, and the amp H-brace and the interior of the bottom panel. I dry fit the remaining panels in the glue-up as support to ensure they go together properly as the glue-up progresses.


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So far, so good...
Tight miter joints make me happy! It's more work to do the glue up in stages this way, but I have much more control over the process. It's looking good...


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Gluing the top panel to the back panel.
I've taken it apart and glued the top panel to the back panel, in the same way as the bottom panel. In this picture, the top panel is facing straight to the left, and the back panel is still lying on the ground.


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The Box of Pain takes shape
With 15 cabinet clamps and two band clamps, this thing is under a great deal of pressure. Here I've glued the side facing the left of the camera on three edges against the top, back, and bottom sides of the sub. This was stressing me out at the start, but ended up being easier than I thought. I should mention that I didn't really have to close the clamps with very much pressure to get it to go together nicely. But I needed every one of these clamps to ensure the box went together right, and one of the other sides didn't go out of whack.


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The other side is on...
Here I've glued on the right panel the same way as the left panel in the last picture. You can see the glue squeeze-out on both sides and along the bottom joint.


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Miter joint glue squeeze out.
I was very happy knowing I've got the right amount of glue in a joint that's supposed to hold back the kind of pressure this things going to experience.


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Miter joints still look great.
I'm beside myself as this goes together as planned. All of a sudden, I'm hooked on this hobby, and my first project doesn't even work yet! The blue tape on the corners prevents glue from sticking the front baffle in place; there's no glue around the top yet. The other tape forms handles to allow front baffle removal.


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Letting it cook overnight.
Now I can relax.


Continued next...
Peter
 
Still More Pics...

The Pics continue... (will it ever stop?)


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The clamps are off.
I'm lucky to have a nice selection of clamps. Nice clamps... goooood clamps.


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Top view.
You can see the amp housing and the miter joints ready to accept the front baffle.


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Sealing with polyurethane...
...is messy but it works. No one will see the inside of the cabinet. Except you... Gack!


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Nice tight miter joints!
I couldn't be happier with how these joints have turned out. I can tell that I made a good choice to do this glue up in stages.


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Cabinet braces installed.
I've glued the braces in and this puppy is dead. I'm surprised at the difference after these are in. The cabinet doesn't appear to resonate at all....and it doesn't even have the 2" thick front baffle glued on yet!


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Routing the amp flange rabbet completed.
The amp fits nicely in the housing. Still have to pre-drill for the screws. Hopefully I don't blow through the back of the cabinet after all this effort to seal it up!


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Close up view.
I've sealed the inside of the amp housing, but, like so much with this project, it's overkill. ;)


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Time for a break.
I've also taken my block plane to remove the glue squeeze-out. Works a treat.


With this construction, the cabinet alone will weigh 90 lbs! With the amp and driver installed, it will tip the scales at 130 lbs....truly a Box of Pain. So that's it's name. Either that or the Backbreaker 6000. :D

Well, that's it for now. I'm working on the front baffle so I can install it, plug in the driver, and test it out.

Check back soon for more...
Peter
 
Front baffle

Thanks F1... I appreciate it. It has been alot of work but fun in it's own way...

I spent some time last night laying out the driver opening cutout in the front baffle. I've made my own circle cutting jig, just because it was probably easier than ordering a Jasper jig. (Plus I'm a cheapie when it comes to things like that...)

Also, I've cut the back of the baffle down to size to fit on the front piece (I'm doing a double-thickness front baffle). When I screwed them together temporarily, it fits extremely nicely. In fact, there's a satisfying hiss as the baffle pushes air out of the cabinet and seats itself into the miter joints as if it's on hydraulics!


Now, the bigger thing is that I've decided to take advantage of this past weekend's Deal of The Weekend at PE to purchase another driver and build... yes, ANOTHER sub, to match this one!!!

I know it will be more work than if I had started them at the same time, but all the advice I got said to go for it... I'll be able to use the second channel of my FBQ2496 Parametric EQ to smooth out the response, and I'll eventually be doing some room treatment. It sounds like several people on the PE Tech talk board are doing this today and are very satisfied...

Anyone have any thoughts out there about running multiple subs? The good and the bad?

Thanks,
Peter
 
Thanks for the link Scott.

I've seen this type of info on Audioholics before, but not this article. It looks good and I'm wanting to see the second article in this series.


I'll be using a variety of different measurement tools once I get the sub completed. I plan to use some PC based Real time analyzer apps and the Room EQ Wizard to adjust the sub output with the Behringer FBQ2496 Parametric EQ.

Still working on the front baffle...!

Peter
 
Front Baffle Update - Pics 1!

I've completed my front baffle and have new pictures. I suppose creating a big box is not that novel, but I thought I'd give an update on what challenges I had finishing the 2" front baffle, routing and rabbeting the driver opening, and test-fitting and glue-up of the baffle assembly.


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Routing the front baffle.
I used a 3/4" wide straight bit with a 1/2" shank to cut the driver rabbet to a depth of 3/4"; this eliminated any chatter and resulted in a smoothly cut rabbet.


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Homemade circle cutting jig.
Obviously it's a pretty simple affair. A 1/4" piece of masonite screwed on as a router base with a few carefully measured holes... I used the drill bit as a pin. It worked like a charm!


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Close up.
Leaving only a small opening for the bit helped keep the dust from going everywhere.


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Driver opening cutout.
I used a 1/4" straight bit to cut down and create the opening. I used my Rigid vac to keep the dust down, and it worked great. I cut out the back opening with my jigsaw, as this produced less dust, didn't dull my router bits, and was quicker.


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Gluing the back piece to the front baffle.
Once this glue-up was done, I then finished the rear opening with my 1" flush trimming bit, running the bearing against the front panel rabbet.


More to come...
 
Front Baffle Pics 2

With the baffle glued up, I'm ready for finishing the opening, drilling mounting holes, test fitting the driver, and cutting chamfers on the backside.


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The finished front baffle.
I cut the rear chamfers with a 1/2" chamfering bit. I originally was looking for a much deepr bit to make bigger chamfers, but after recessing the driver by 3/4", it opened up the back of the driver, The chamfers didn't need to be as deep to give good air flow out of the rear of the driver.


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Closeup of the rear of the panel.
Here's a better view of the back panel. I spent too much time thinking about this before jumping in...


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Driver recessed into baffle.
Originally, I didn't see that the Drake design called for recessing the driver into the front baffle, but once I did this made the rest of the baffle construction easier.


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The RSS315HF-4 in position
With the driver positioned in the 2" baffle, the mounting screws just fit nicely enough into the t-nuts to hold.


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Driver test fit.
This went together easily the first time. Now I can't wait to get this thing installed.


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Front baffle with driver.
In this test fit, you can see there is plenty of room for air movement out of the back of the driver.


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Glue-up.
A little brute force ensures a good bond. The worst thing about the glue-up is trying to work rapidly to get an even spread of glue on eight miter joints and eight vertical surfaces, and then get it all put together before the MDF swells and it won't fit together. Fortunately, it didn't take too long, and went together nicely.


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No turning back now...
All the clamps are tight, and all the joints look perfect.


Once the clamps come off, I will seal the interior baffle joints with polyurethane, pre-drill for the amp flange screws, then install both the driver and amp for testing.

The Backbreaker 6000.1 is born.

Peter
 
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