RL-P18 meets the "DOH! button" - AVS Forum
Forum Jump: 
Reply
 
Thread Tools
post #1 of 330 Old 10-10-2007, 11:03 AM - Thread Starter
btp
AVS Special Member
 
btp's Avatar
 
Join Date: Apr 2005
Location: Seattle-land
Posts: 1,197
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10


Good lord... what have I done?!



Suffice it to say I'm totally out of control with Google Sketchup. I'm not done yet and not really happy with the braces, so this is definitely a "work in progress".

On the bright side, no trees were harmed in the making of this drawing!

Regarding the box, it's 26H x 30D x49W. Target net volume 17 cu ft, 14.5 Hz tune. Port I.D. is around 8.375". It's a bit long at 35.25", but that does allow it to terminate nicely in the third brace.

Bradley

Signature Challenged.
btp is offline  
Sponsored Links
Advertisement
 
post #2 of 330 Old 10-10-2007, 11:19 AM
AVS Special Member
 
ssabripo's Avatar
 
Join Date: Feb 2004
Location: Plantation, Floriduh
Posts: 6,008
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 13
good stuff Bradley!!

hey, at least you didn't have to do that crap in AutoCAD, which SUCKS monkey balls!!!

ssabripo is offline  
post #3 of 330 Old 10-10-2007, 12:23 PM
AVS Special Member
 
Kevin_Wadsworth's Avatar
 
Join Date: Dec 2002
Location: Columbus, OH
Posts: 1,184
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked: 13
Man, I need to spend some more time playing with Sketchup. I can do floorplans and wall, bu tI haven't tried cabinetry.
Kevin_Wadsworth is offline  
post #4 of 330 Old 10-10-2007, 04:42 PM - Thread Starter
btp
AVS Special Member
 
btp's Avatar
 
Join Date: Apr 2005
Location: Seattle-land
Posts: 1,197
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by ssabripo View Post

good stuff Bradley!!

hey, at least you didn't have to do that crap in AutoCAD, which SUCKS monkey balls!!!

Thanks! I've never used AutoCAD, but I'll take your word for it.

Here's the latest draft.



I think the only thing left to do is add some donut support rings for the port tube. I'm not going to bother trying to model the flares or rounded edges.

The smaller holes, or "swiss cheese", aren't really necessary. I'm just a little worried about coming in at 17.0 cubic feet (or higher) as planned. I'll need to add up the volume of all the bracing and port tube once the "ink" has dried on the design.

Signature Challenged.
btp is offline  
post #5 of 330 Old 10-10-2007, 11:11 PM
AVS Special Member
 
armystud0911's Avatar
 
Join Date: Jul 2006
Location: Cincinnati
Posts: 4,423
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 14
So where do we get these 8.375" ports?
armystud0911 is offline  
post #6 of 330 Old 10-10-2007, 11:48 PM - Thread Starter
btp
AVS Special Member
 
btp's Avatar
 
Join Date: Apr 2005
Location: Seattle-land
Posts: 1,197
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by armystud0911 View Post

So where do we get these 8.375" ports?

What I have is Sakrete brand concrete form tubes from Home Depot. You have to cherry pick the largest "8 inch nominal" tubes they have because they are not all exactly the same size. The manufacturer states that the actual dimension to vary as much as half an inch, so they can stuff tubes inside of tubes (to save space and lower shipping costs, I presume).

I will say these tubes are kind of flimsy. I wonder how much stronger actual Sonotube brand tubes are in this size.

On another note, the bracing ate up too much volume, putting me below 17 ft^3, so I'm back to the drawing board now.

Signature Challenged.
btp is offline  
post #7 of 330 Old 10-11-2007, 10:17 AM - Thread Starter
btp
AVS Special Member
 
btp's Avatar
 
Join Date: Apr 2005
Location: Seattle-land
Posts: 1,197
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
So, I put the braces on a diet. Simplified things. Here's the latest revision. Looks like I have an issue to deal with at the port outlet. That one internal brace is going to interfere with the big 1.5" radius flare I'm going to do.


Signature Challenged.
btp is offline  
post #8 of 330 Old 10-11-2007, 10:29 AM
AVS Special Member
 
NEO Dan's Avatar
 
Join Date: Jul 2006
Location: North East Ohio
Posts: 2,978
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 11
Bradley,
DOH' that looks great

I for one deffinately want to see some pics of this build, very cool



Later
Dan

Regards,
Dan
NEO Dan is offline  
post #9 of 330 Old 10-11-2007, 10:29 AM
AVS Special Member
 
jpmst3's Avatar
 
Join Date: Dec 2005
Location: Davidsville, PA
Posts: 8,115
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Liked: 186
Quote:
Originally Posted by btp View Post

What I have is Sakrete brand concrete form tubes from Home Depot. You have to cherry pick the largest "8 inch nominal" tubes they have because they are not all exactly the same size. The manufacturer states that the actual dimension to vary as much as half an inch, so they can stuff tubes inside of tubes (to save space and lower shipping costs, I presume).

That is interesting, never knew that.

Quote:
Originally Posted by btp View Post

On another note, the bracing ate up too much volume, putting me below 17 ft^3, so I'm back to the drawing board now.

Bracing and the volume are not exact sciences. So, differences of like .2 cubic feet are not going to radically alter the sound or tuning point. Just like a half inch difference in port length may change things from 13 to 13.2 Hz tuning or something along those lines. Combine that with small variances in drivers vs. specs, etc. it all comes out in the wash. Just get things close...don't sweat the minute details.

jpmst3 is offline  
post #10 of 330 Old 10-11-2007, 02:37 PM - Thread Starter
btp
AVS Special Member
 
btp's Avatar
 
Join Date: Apr 2005
Location: Seattle-land
Posts: 1,197
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by jpmst3 View Post

Combine that with small variances in drivers vs. specs, etc. it all comes out in the wash. Just get things close...don't sweat the minute details.

You know, I keep telling myself that... but it still bugs the $#@!*&#% out of me! Does that mean I'm anal?

Signature Challenged.
btp is offline  
post #11 of 330 Old 10-11-2007, 02:40 PM
Bass Enabler
 
Scott Simonian's Avatar
 
Join Date: Oct 2001
Location: Clovis, CA
Posts: 13,201
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 145 Post(s)
Liked: 639
Quote:


You know, I keep telling myself that... but it still bugs the $#@!*&#% out of me! Does that mean I'm anal?

Ahhh, I was doing the same thing in my build thread. Such minute things arent something to worry about though so youre all good, Bradley.

Can't wait to see some pics of this, looks intricate and very well thought out.

My Dual 18" LLT subs 120dB down to 10hz

 

Plan9Reloaded Co-host

Listen to the Plan9Reloaded Gaming and Technology Podcast (may contain NSFW language)

https://soundcloud.com/plan9reloaded/sets/podcast - direct pod link

http://plan9reloaded.com/site/ - main website

Scott Simonian is offline  
post #12 of 330 Old 10-11-2007, 02:47 PM
AVS Addicted Member
 
noah katz's Avatar
 
Join Date: Apr 1999
Location: Mountain View, CA USA
Posts: 20,377
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 102 Post(s)
Liked: 138
"On another note, the bracing ate up too much volume, putting me below 17 ft^3, so I'm back to the drawing board now."

If you model the different volumes in a s/w program I bet the difference is at most a tenth or two of a dB.

What's so magic about 17 cf anyway?

Noah
noah katz is offline  
post #13 of 330 Old 10-11-2007, 03:00 PM - Thread Starter
btp
AVS Special Member
 
btp's Avatar
 
Join Date: Apr 2005
Location: Seattle-land
Posts: 1,197
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Nothing is magic about 17 cubic feet at all. Indeed it is somewhat arbitrary compared to 16 or 18. I was tempted to go bigger but finally set 17 as my target goal. So really I'm just being neurotic about trying to hit that design goal with the other constaints I've set up for myself. I kinda shot myself in the foot by limiting the height of the box to 26 inches and already having the MDF cut for those major dimensions. Worst case, I could buy a couple more sheets of MDF and bump the size of the box up by 1/2 an inch or so. But... like you and others have pointed out, no one would ever notice the difference (including me). It's the KNOWING that is the hard part.

Signature Challenged.
btp is offline  
post #14 of 330 Old 10-11-2007, 03:08 PM - Thread Starter
btp
AVS Special Member
 
btp's Avatar
 
Join Date: Apr 2005
Location: Seattle-land
Posts: 1,197
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by NEO Dan View Post

Bradley,
DOH' that looks great

I for one deffinately want to see some pics of this build, very cool

Thanks, Dan. I was impressed and inspired by your elegant and simple box design and the models you did with Sketchup.

In addition to mucking around with Google Sketchup, I've been amassing tools, supplies and MDF for the past week or so. The real fun will begin this weekend.



Maybe I need a "Got MDF?" bumper sticker.

Signature Challenged.
btp is offline  
post #15 of 330 Old 10-11-2007, 03:12 PM
AVS Special Member
 
Andrikos's Avatar
 
Join Date: Apr 2003
Location: Stuttgart
Posts: 3,910
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 12
Wow, you guys beat the crap out of my "sketch on a white board" designs.
Kudos!

I didn't know about ggl sketchup. I'm d/ling right now.
Thanks!

Next projector will have LEDs, >=1080 res, >=10 bit color, >14bit CR, >9 bit ANSI CR, >=120Hz, >16ft.L on 12ft 2.35:1 screen, <$12bit price

My 1st line array design

My ongoing Line Array Design
Andrikos is offline  
post #16 of 330 Old 10-11-2007, 04:00 PM - Thread Starter
btp
AVS Special Member
 
btp's Avatar
 
Join Date: Apr 2005
Location: Seattle-land
Posts: 1,197
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Success!



Looking good now. Actual net volume will be higher after flaring the port (on the inside) and running a roundover bit along the edges of the bracing. There's also some intersection of bracing that I did not take into account, so I get that space back, so to speak.

Signature Challenged.
btp is offline  
post #17 of 330 Old 10-11-2007, 04:02 PM
Bass Enabler
 
Scott Simonian's Avatar
 
Join Date: Oct 2001
Location: Clovis, CA
Posts: 13,201
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 145 Post(s)
Liked: 639
You got it, Bradley! Now go build it!

My Dual 18" LLT subs 120dB down to 10hz

 

Plan9Reloaded Co-host

Listen to the Plan9Reloaded Gaming and Technology Podcast (may contain NSFW language)

https://soundcloud.com/plan9reloaded/sets/podcast - direct pod link

http://plan9reloaded.com/site/ - main website

Scott Simonian is offline  
post #18 of 330 Old 10-11-2007, 07:26 PM
AVS Special Member
 
Spezzy's Avatar
 
Join Date: Jun 2006
Location: Huntington Beach, CA
Posts: 1,403
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 12
Do you guys think that bracing similar to this would be sufficient for 25 cu ft boxes?

"The choices we make define our lives, because choice, not chance, determines destiny"

They call me the 18 year old DJ Audiophile-upgradeitis infected-guy!
Spezzy is offline  
post #19 of 330 Old 10-12-2007, 09:46 AM - Thread Starter
btp
AVS Special Member
 
btp's Avatar
 
Join Date: Apr 2005
Location: Seattle-land
Posts: 1,197
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by Spezzy View Post

Do you guys think that bracing similar to this would be sufficient for 25 cu ft boxes?

I don't see why the design wouldn't scale to that size, however there are different opinions out there about what kind of bracing is ideal. "Window bracing" seems to be mentioned most often. By that I assume they mean stick style braces that cross at right angles, looking like a classic "window" with many sections. Of course the braces can still be cut from sheets of MDF.

There isn't a single right way to do it, although there probably better and worse ways.

Signature Challenged.
btp is offline  
post #20 of 330 Old 10-12-2007, 10:35 AM
Bass Enabler
 
Scott Simonian's Avatar
 
Join Date: Oct 2001
Location: Clovis, CA
Posts: 13,201
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 145 Post(s)
Liked: 639
So, Bradley...do you start the cutting this weekend?

My Dual 18" LLT subs 120dB down to 10hz

 

Plan9Reloaded Co-host

Listen to the Plan9Reloaded Gaming and Technology Podcast (may contain NSFW language)

https://soundcloud.com/plan9reloaded/sets/podcast - direct pod link

http://plan9reloaded.com/site/ - main website

Scott Simonian is offline  
post #21 of 330 Old 10-12-2007, 10:49 AM - Thread Starter
btp
AVS Special Member
 
btp's Avatar
 
Join Date: Apr 2005
Location: Seattle-land
Posts: 1,197
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
That was the plan. But I'm considering whether or not to move the port closer to the center of the box (front-to-back wise). Right now it's about equal distance from the back of the driver and the interior rear wall of the box. 5 inches clearance, which is less than one port diameter. On the bright side there is a full 11.5 inches between the end of the port and the side wall that it "points" at. My gut feeling is that it would be OK like it is, but I don't know that it is ideal or optimal. Plus, someone over on the Shack also suggested "window bracing" would be more efficient, consume less space.

Signature Challenged.
btp is offline  
post #22 of 330 Old 10-12-2007, 11:05 AM
Bass Enabler
 
Scott Simonian's Avatar
 
Join Date: Oct 2001
Location: Clovis, CA
Posts: 13,201
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 145 Post(s)
Liked: 639
Quote:


Right now it's about equal distance from the back of the driver and the interior rear wall of the box. 5 inches clearance, which is less than one port diameter. On the bright side there is a full 11.5 inches between the end of the port and the side wall that it "points" at.

Then I think you will be perfectly fine. Its the opening of the port inside that needs the clearance. Unless I am missing something. So the the port opening on the inside has 11 inches of room? Even if you have thick fiberglass (like mine, about 3 inches thick) then you will still have a whole 8 inches of clearance. Yeah, thats more than fine. You'll be hard pressed to get these ports to compress anyway so I think you're alright.

Quote:


Plus, someone over on the Shack also suggested "window bracing" would be more efficient, consume less space.

Ah, well everyone has their preference to how they like to build things. I think it was Steve Callas that recommended that, right? Window bracing is very effective and allows for much space to be saved. Although if you feel that you are confident in being able to build and cut those braces then there is nothing to be worried about. Some just dont like to cuts tons of circles.

After going through my build...I kinda feel the same way. Eventually, you will go crazy....stay up all night, eating nothing but bugs off the floor. Scratching circles all over the walls with an insane voice, "Circles! Circles! They are EVERYWHERE!!!!"

My Dual 18" LLT subs 120dB down to 10hz

 

Plan9Reloaded Co-host

Listen to the Plan9Reloaded Gaming and Technology Podcast (may contain NSFW language)

https://soundcloud.com/plan9reloaded/sets/podcast - direct pod link

http://plan9reloaded.com/site/ - main website

Scott Simonian is offline  
post #23 of 330 Old 10-12-2007, 11:12 AM - Thread Starter
btp
AVS Special Member
 
btp's Avatar
 
Join Date: Apr 2005
Location: Seattle-land
Posts: 1,197
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by Scott Simonian View Post

Then I think you will be perfectly fine. Its the opening of the port inside that needs the clearance. Unless I am missing something. So the the port opening on the inside has 11 inches of room? Even if you have thick fiberglass (like mine, about 3 inches thick) then you will still have a whole 8 inches of clearance. Yeah, thats more than fine. You'll be hard pressed to get these ports to compress anyway so I think you're alright.

Yes, sir. Here's a picture. Keep in mind the Sketchup drawing does not show the 1.5" radius flare that will be done on the port tube (on BOTH ends).


Signature Challenged.
btp is offline  
post #24 of 330 Old 10-13-2007, 11:20 PM
AVS Special Member
 
Willd's Avatar
 
Join Date: Jan 2003
Location: Charlotte, NC
Posts: 5,647
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Edited.
Willd is offline  
post #25 of 330 Old 10-14-2007, 01:01 AM - Thread Starter
btp
AVS Special Member
 
btp's Avatar
 
Join Date: Apr 2005
Location: Seattle-land
Posts: 1,197
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Thanks, Will. I'm going with 17 cu ft and 14.5 Hz tune so maybe I won't hit 114 dB @ 12 Hz. But that's OK. I trust it will be significantly more than 102.

Here's the latest box design. Hopefully this will be "golden". If anyone has comments or suggestions, now is the time... before I start cutting up the big pile of MDF in my garage!


Signature Challenged.
btp is offline  
post #26 of 330 Old 10-14-2007, 01:09 AM
AVS Special Member
 
Willd's Avatar
 
Join Date: Jan 2003
Location: Charlotte, NC
Posts: 5,647
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:


Thanks, Will. I'm going with 17 cu ft and 14.5 Hz tune so maybe I won't hit 114 dB @ 12 Hz. But that's OK. I trust it will be significantly more than 102.

Oh yeah, right. In that case, you won't be. Really strong output down to ~13Hz though!

That last sketchup looks great.
Willd is offline  
post #27 of 330 Old 10-15-2007, 10:22 AM - Thread Starter
btp
AVS Special Member
 
btp's Avatar
 
Join Date: Apr 2005
Location: Seattle-land
Posts: 1,197
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Scott... just sent you a PM, but if anyone else has experience mounting a RL-P18, feel free to chime in.

Did you wind up going with the 10-32 size screws (and hurricane nuts) or the 1/4-20? Which binding posts did you go with?

For anyone following this thread... here is the final design as posted over on the Shack. The Sketchup file is on my web server too if anyone wants to download it.




Signature Challenged.
btp is offline  
post #28 of 330 Old 10-15-2007, 11:03 AM
Bass Enabler
 
Scott Simonian's Avatar
 
Join Date: Oct 2001
Location: Clovis, CA
Posts: 13,201
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 145 Post(s)
Liked: 639
10-32's...

But you got that PM already.

Watch your fingers while dropping in this puppy.

My Dual 18" LLT subs 120dB down to 10hz

 

Plan9Reloaded Co-host

Listen to the Plan9Reloaded Gaming and Technology Podcast (may contain NSFW language)

https://soundcloud.com/plan9reloaded/sets/podcast - direct pod link

http://plan9reloaded.com/site/ - main website

Scott Simonian is offline  
post #29 of 330 Old 10-15-2007, 07:53 PM
Member
 
NewbieMark's Avatar
 
Join Date: Sep 2007
Posts: 38
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
I can really see the progress you have made in sketchup, from the first drawing...
Maybe someday I will figure out how to do all of that.
Man, that looks good. That thing looks solid.
Is that a tripple wall in the driver mounting area?
Did you do that just to have more depth for the screws, or is there a need for that much reinforcement?
I am curious on the binding posts myself.

I'm glad you are starting before me, that way I can see that 1.5" roundover, and you can tell me your opinion of swinging that thing on a router....lol
I mounted mine into the MV12 today, and just about fell over laughing, because everything about this project has to be huge and heavy, right down to the freakin router bits...My wife thinks I've lost my mind...ROFL---it took her 10 years to figure that out.
NewbieMark is offline  
post #30 of 330 Old 10-15-2007, 11:30 PM - Thread Starter
btp
AVS Special Member
 
btp's Avatar
 
Join Date: Apr 2005
Location: Seattle-land
Posts: 1,197
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Oh yeah... it's been "fun" learning how to make Sketchup do what I want. It still pisses me off sometimes when I change the design and it suddenly just deletes the "face"/surface between the lines.

There is just one reinforcement panel behind the front panel. It kind of looks like three because I hid the top panel and you're seeing the 3/4" gap between the top of driver support panel and the top of the front panel. (Hope that made sense.) The driver mounts to that supporting panel so it gets at least some recess from the front panel. Of course the surround on the RL-P18 is so big, it will still stick out considerably from the front panel, despite the driver being recessed by 3/4"!

Yep. That 1.5" radius roundover bit is quite hefty. I specifically bought a router that would go SLOW ENOUGH (under 10,000 RPM) for it!

Here's what I ordered today from Parts Express:

Dayton BPA-38G HD Binding Post Pair Gold
Cast Frame #10-32 Speaker Mounting Kit
#10-32 Hurricane Nuts 50 Pcs.

I'm sure my girlfriend thinks I'm crazy but she's too busy working on her thesis to care.

Signature Challenged.
btp is offline  
Reply DIY Speakers and Subs

User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off