Single 8" in vented cabinet - Home Theater Forum and Systems - HomeTheaterShack.com

 
Thread Tools
post #1 of 9 Old 01-26-11, 10:22 PM Thread Starter
Shackster
 
Join Date: Jan 2011
Location: Seattle area
Posts: 12
Single 8" in vented cabinet - Finished!

About halfway done with this one - the box is together and the components work, so all that's left is the finishing. It's a single 8" Dayton QT210-4 in a 40-litre box, tuned at 35 hz. I'm working with ⅝" particle board.

The optimal box size for this driver works well for me. The sharp cut-off below 35 is what I want - this isn't going to be a room-shaker, I just want it to fill in below where my 5" mains leave off. They're self-powered, so I went with a self-powered sub as well.

At 20" high (plus the 1¼" from the particle board), it just fits under my desk. I went with four vents instead of just one for aesthetic reasons. Does anyone think I'm going to need cross-bracing for 100 watts?

The current finishing plans are to round off the corners and then paint it black to match the mains. I've been testing on scraps to work out how to get the finish to look good, I suspect it's going to involve a lot of filling and sanding.

I don't have a measurement mic handy, but by ear, it sounds about how the plot predicted. Lots of power between 60 and 40, and then it's almost gone by 30. It fits in quite nicely with my mains, and manages to hide under my desk in the process.
Attached Thumbnails
Single 8" in vented cabinet-isd.jpg  

Single 8" in vented cabinet-interior1.jpg  

Attachments

Last edited by Piromancer; 01-30-11 at 12:00 PM. Reason: Updating title
Piromancer is offline  
Sponsored Links
Advertisement
 
post #2 of 9 Old 01-27-11, 02:33 AM
Shackster
 
Join Date: Jul 2010
Location: Lebanon, Missouri
Posts: 61
Re: Single 8" in vented cabinet

Are all of the walls doubled up with the 5/8" PBoard? If so I wouldn't see a need for much bracing. If it were my build, and all the walls were 1 1/4", I would just throw mabey two 1" dowel rod braces in there attached to each side wall. Even with the enclosure glued up it could still easily be done by drilling 4 holes to attach the braces to the walls with wood screws, and try to squeez a little glue in between if you want for added measure. The screw heads will be covered by your enclosures finish, especially if they are countersunk, and filled. Be sure to pre-drill the holes in the dowels if you go that route as well. This will prevent them from splitting when the screws go in. Hope this helps, and its a good looking little sub so far!
HTNut42 is offline  
post #3 of 9 Old 01-27-11, 03:18 AM
Elite Shackster
 
Mike P.'s Avatar
Mike
 
Join Date: Apr 2007
Location: Chitek Lake, Sask.
Posts: 19,397
Re: Single 8" in vented cabinet

I agree, the side panels could use a couple of dowel braces.

What diameter are the port tubes and how long are they?




We're all in this together!


To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.

Mike P. is offline  
 
post #4 of 9 Old 01-27-11, 07:09 AM
Senior Shackster
 
1Michael's Avatar
Michael
 
Join Date: Nov 2006
Location: Chesapeake Virginia
Posts: 707
Re: Single 8" in vented cabinet

Quote:
Piromancer wrote: View Post
Does anyone think I'm going to need cross-bracing for 100 watts?
In my world...always

Michael
1Michael is offline  
post #5 of 9 Old 01-27-11, 12:29 PM Thread Starter
Shackster
 
Join Date: Jan 2011
Location: Seattle area
Posts: 12
Re: Single 8" in vented cabinet

The port tubes are "1½ inch" schedule 40 drain pipe, which has an actual ID of 1.6". They each project into the box 9¾", for a total length of 10¾. I've attached a diagram of all the relevant measurements.

All the sides are single sheets of particle board, the only place where they're double-thickness is where the ports attach to the box. I'll have to do some thinking on how to cross-brace, if you're suggesting dowel braces for a double-thick box, that sounds to me like a single-thick box would need a full brace or two.
Attached Thumbnails
Single 8" in vented cabinet-portdetail.png  

Piromancer is offline  
post #6 of 9 Old 01-27-11, 01:15 PM
Elite Shackster
 
Mike P.'s Avatar
Mike
 
Join Date: Apr 2007
Location: Chitek Lake, Sask.
Posts: 19,397
Re: Single 8" in vented cabinet

You have the same port area of a 3.2" diameter port so the port air speed shouldn't be a problem. Is that a Dayton plate amp?




We're all in this together!


To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 signatures.

Mike P. is offline  
post #7 of 9 Old 01-27-11, 04:49 PM Thread Starter
Shackster
 
Join Date: Jan 2011
Location: Seattle area
Posts: 12
Re: Single 8" in vented cabinet

Indeed it is the Dayton. It's the 100-watt version, which is underpowered for the driver (which maxes out at 150 watts RMS), but seemed to be the best match I could find. While testing, I don't think I ever turned it up over half, and it's currently sitting at about 1/4 power.

WinISD gave the airspeed through the vents at a max of mach 0.02. I suppose I could have used 2" vents and lowered that even further, but then I would have needed 19" long vents in a box only 15" deep. Adding elbows and such to make them fit and keep the ends clear of the sides would have been problematic with four vents in a small box.
Piromancer is offline  
post #8 of 9 Old 01-28-11, 03:02 PM Thread Starter
Shackster
 
Join Date: Jan 2011
Location: Seattle area
Posts: 12
Re: Single 8" in vented cabinet

Apologies for double-posting, but here's some progress. After a lot of sanding, filling, sanding, priming, sanding, and priming yet again, the first top coat is on and drying. I'm starting to see why veneer is such a popular finishing option. Here it is primed, the eventual finish will be a gloss black.
Attached Thumbnails
Single 8" in vented cabinet-primed1.jpg  

Single 8" in vented cabinet-primed2.jpg  

Piromancer is offline  
post #9 of 9 Old 01-30-11, 02:27 AM Thread Starter
Shackster
 
Join Date: Jan 2011
Location: Seattle area
Posts: 12
Re: Single 8" in vented cabinet

And it's finished! I'm still not happy with how the non-rounded corners came out, my next build will definitely have a different finish on it. This was a lot of work to get even close to right. (It's by no means perfect, there are a lot of little defects when you look at it up close.) I like the chromed socket-head bolts on the back of the box, if I had a better-looking driver, I'd happily use them around the front and show it off.

It makes a cute little system with my mains, I didn't know they were going to end up the same height. All three speakers are happily hanging out at about a quarter of full power, which is plenty. My computer is running in single-digit percentages of volume output and it's a comfortable listening volume.

So... Anyone in the Seattle area have a measurement mic I can use? I'd love to see the box's frequency response.
Attached Thumbnails
Single 8" in vented cabinet-finished1.jpg  

Single 8" in vented cabinet-finished3.jpg  

Single 8" in vented cabinet-finished4.jpg  

Single 8" in vented cabinet-system1.jpg  

Piromancer is offline  
Reply

Bookmarks

Tags
cabinet , single , vented

Quick Reply
Message:
Options

Register Now




PLEASE COMPLETE ALL REQUIRED FIELDS BELOW... THANKS!

REQUIRED FIELDS ON THIS PAGE
YOU MUST COMPLETE ALL OF THESE

Username
Password
Confirm Password
Email Address
Confirm Email Address
Random Question
Random Question #2




User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
PLEASE READ BELOW PRIOR TO ENTERING AN EMAIL ADDRESS!

ATTENTION!

YOU MUST ACTIVATE YOUR ACCOUNT!

Activation requires you reply to an email we will send you after you register... if you do not reply to this email, you will not be able to view certain areas of the forum or certain images... nor will you be able download software.

AN INVALID EMAIL ADDRESS WILL CAUSE YOUR ACCOUNT TO BE DELETED!

See our banned email list here: Banned Email List

We DO NOT respond to spamcop, boxtrapper and spamblocker emails... please add @hometheatershack DOT com to your whitelist prior to registering or you will get nowhere on your registration.


Email Address:
OR

Log-in










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



Posting Rules  
You may post new threads
You may 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 is not allowed!
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

 


For the best viewing experience please update your browser to Google Chrome