DIY Slotted Port Dayton Audio UM12-22 12 Project - AVS Forum
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post #1 of 12 Old 06-11-2013, 03:28 PM - Thread Starter
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Starting my project soon and wanted to get some feedback on design, driver, and plate amp. This is my first DIY build so any help would be appreciated. From what I have already read in the DIY forums I am sure I will get some good feedback here.

Driver: Dayton Audio UM12-22
Amp: Dayton Audio SPA500

Design after a long battle with Google Sketchup:


I plan to round off the entrances to the slotted port and the corners inside of the port. I also plan on rounding all the cutouts in the center brace. Top, sides, back and bottom will be 3/4 in and the front will be 1 1/2 inch.

Port size is 1 3/4" x 10" x 27"

WinISD Gain graph


I do appreciate all the help and, as mentioned above, I welcome any feedback from those of you who are more experience with the DIY process.

Thanks!!
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post #2 of 12 Old 06-11-2013, 05:34 PM
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I hear you about battling with sketchup. the learning curve is a pain. Once you learn to make each piece of wood into a separate component and to draw each component in place, life gets easier.

two points (maybe more):
1. Dayton UM15-22 is only $20 more and will give almost 2x the extension. At 15.5" OD it just about fits in the same box design.

2. Your box needs more bracing, particularly on the side panels. Ideally there would be less than8" between braces.

3. That may be one of the better plate amps but its not enough to do justice to those drivers. I would go with something like an iNuke 1000 DSP for $299. More power, much much better equalization and crossover capability. Only downside is its not a plate amp and needs a fan swap to cure fan noise. To make best use of it, you'll need a microphone and a sound card and then you are on that slippery slope to full DIY.

4. Someone should take a close look at your tune. Fbox, vent air velocity, are critical. You'll probably need a high pass filter to protect the driver from overexcursion at frequencies below Fbox.

Have fun!

Jack
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post #3 of 12 Old 06-11-2013, 06:28 PM
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Quote:
Originally Posted by JackNC View Post

I hear you about battling with sketchup. the learning curve is a pain. Once you learn to make each piece of wood into a separate component and to draw each component in place, life gets easier.

two points (maybe more):
1. Dayton UM15-22 is only $20 more and will give almost 2x the extension. At 15.5" OD it just about fits in the same box design.

2. Your box needs more bracing, particularly on the side panels. Ideally there would be less than8" between braces.

3. That may be one of the better plate amps but its not enough to do justice to those drivers. I would go with something like an iNuke 1000 DSP for $299. More power, much much better equalization and crossover capability. Only downside is its not a plate amp and needs a fan swap to cure fan noise. To make best use of it, you'll need a microphone and a sound card and then you are on that slippery slope to full DIY.

4. Someone should take a close look at your tune. Fbox, vent air velocity, are critical. You'll probably need a high pass filter to protect the driver from overexcursion at frequencies below Fbox.

Have fun!

Jack

This.......at the least you need more bracing and make sure the port airspeed and resonance are ok
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post #4 of 12 Old 06-11-2013, 07:04 PM
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You can use dowels or furring strips for bracing. Saves you time and not that expensive.
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post #5 of 12 Old 06-11-2013, 10:13 PM - Thread Starter
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Quote:
Originally Posted by JackNC View Post

I hear you about battling with sketchup. the learning curve is a pain. Once you learn to make each piece of wood into a separate component and to draw each component in place, life gets easier.

two points (maybe more):
1. Dayton UM15-22 is only $20 more and will give almost 2x the extension. At 15.5" OD it just about fits in the same box design.

2. Your box needs more bracing, particularly on the side panels. Ideally there would be less than8" between braces.

3. That may be one of the better plate amps but its not enough to do justice to those drivers. I would go with something like an iNuke 1000 DSP for $299. More power, much much better equalization and crossover capability. Only downside is its not a plate amp and needs a fan swap to cure fan noise. To make best use of it, you'll need a microphone and a sound card and then you are on that slippery slope to full DIY.

4. Someone should take a close look at your tune. Fbox, vent air velocity, are critical. You'll probably need a high pass filter to protect the driver from overexcursion at frequencies below Fbox.

Have fun!

Jack

Hey, Jack, I appreciate the feedback. Once I got the hang of Sketchup it really started to get fun.

I should tell you a little more about my room as this may weigh in on the design. The room is 23' x 14' with 18' vaulted ceiling to a 7.5' length wise. I currently own a Epik Legend sub that is corner loaded on the short side of the room. I am hoping a vented sub on the tall side of the room will help fill the room. The sub will be for mostly a HT application. Thoughts??

1. Yeah, I ran models in WinISD and BassBox for both the UM12-12 and the UM15-15. According to the models the 12 seems to look better. Perhaps I need to take another look at the 15. Maybe I punched in some of the numbers incorrectly. Honestly, I have no clue about drivers and what all the numbers mean. I just picket ones from Parts Express that seem reasonable price wise and that seemed to have good reviews. I did notice in some of my research that both the 12 and 15 have a QTS larger that .4 and really should be used in sealed enclosures.

2. I did consider adding more bracing from side to side using dowels I just got lazy and did not add them in the model. I see lots of horizontal braces in the future so I will fiddle with the model and add some bracing tomorrow and see where I get.

3. I really wanted to go with a plate amp. Adding another amp to my setup just causes another set of space issues. Is there another plate amp you could recommend that would work for both the 12 and the 15?

4. I am concerned about the tuning for sure. WinISD and BassBox seemed to give me different numbers for port length. Not sure what that is about. So, what kind of numbers for Fbox and vent air velocity should I want? I understand what the Vent Air Velocity is but not sure I understand Fbox? ARe there some other tools out there to help with some of these calculations?

5. Any advice on what materials I should use?

Here is the VAV plot from BassBox


With bracing:


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post #6 of 12 Old 06-12-2013, 08:59 AM - Thread Starter
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Originally Posted by Mrkazador View Post

You can use dowels or furring strips for bracing. Saves you time and not that expensive.

Good thought on the dowels for bracing. I have added that bracing to my model.

Thanks!!
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post #7 of 12 Old 06-12-2013, 09:06 AM
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With that big a room, you won't get much help from room gain. So I agree a vented sub is best and corner loading will help. A vented sub cabinet should be as big as you or your wife can stand. Bigger is always better up until you get ridiculously large.

Fbox is the tuning frequency of the box. For HT, you'll want an Fbox below 20 Hz. The length and cross section area of the bent determines Fbox. The larger the box, the shorter the vent needed to reach the desired Fbox. If you don't make the vent fat enough (Xsection area) the air getting pushed through it will make noise. WinISD I think shows vent air velocity on one of its screens. Shoot for max velocity below 30 m/s and preferably half that but that it is difficult to achieve. It will be easier with a larger box.

SInce these numbers means so little to you, you might be better copying or at least following one of the vented sub threads you can find in the archives.

Jack
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post #8 of 12 Old 06-13-2013, 05:03 PM
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I think you are going to need to add braces on the top as well...

If it's not a BIG screen, it's not a theater...
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post #9 of 12 Old 06-13-2013, 05:14 PM
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Did some rough calculations based on your posted info. Looks like 4.5 ft3 tuned to 18.5 hz to me, which shows a 1 db hump centered at 40hz. The amp has an 18hz HPF, your air velocity and cone excursion are perfectly fine with 500 watts.
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post #10 of 12 Old 06-13-2013, 10:26 PM - Thread Starter
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Quote:
Originally Posted by Jon S View Post

I think you are going to need to add braces on the top as well...

So, you are suggesting I add vertical bracing as well? Would I need it both the upper and lower sections?
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post #11 of 12 Old 06-13-2013, 10:29 PM - Thread Starter
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Quote:
Originally Posted by Jay1 View Post

Did some rough calculations based on your posted info. Looks like 4.5 ft3 tuned to 18.5 hz to me, which shows a 1 db hump centered at 40hz. The amp has an 18hz HPF, your air velocity and cone excursion are perfectly fine with 500 watts.

Excellent, thanks for the info. Much appreciated.
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post #12 of 12 Old 07-18-2013, 08:14 AM - Thread Starter
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well, I recently realized that the numbers for my original design are not what I really am after. I think it is back to the drawing board. I am currently looking at some sonotube and other down firing ported designs. A DIY sub is still in my future and I hope to share with you all when I finally decide.

I sincerely want to thank all of you who offered suggestions and information. Being new to this process I still have lots to learn.

Thanks!!
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