My summertime DIY project. (1 Viewer)

[bobbyg2]

No way of getting a .5 Qtc without watching the cone shoot through the wall... So, I guess I just need a different driver?

 

[Robert_J]

Have you defined any goals? What will this sub be used for - music, movies or both? How large is the room? How loud do you want to listen? Unless you define those, you are just building to be building. If you are on budget and want to learn, build a few boxes. The .5cf is great to start out with. Then build a larger one with a Qtc of .707. Finally the largest with a Qtc of .5. Learn how each sounds. That way when you graduate to largers subs, you will be able to relate those graphs to real experience.

-Robert

 

[bobbyg2]

I want to use it mainly for music with occasional gaming, I'm in a small room (about 11' x 9'), I want it to be loud enough to fill the room but not so loud as to get complaints from the neighbors, and I don't really have the room for a gargantuan sized enclosure that will take up the whole room. But, I want it to be cheap, as I will be moving into my own house next year and will be putting this in my bedroom and buying a bigger and better one for the living room.

 

[Robert_J]

Build the .5cf box. The hump in the frequency response will be beneficial for special effects of games and that @#$# rap music you kids listen to now days.

-Robert

 

[bobbyg2]

I don't listen to rap.

So, that Qtc is fine for my use? Just, not all that great for movies? I'm probably never going to use it for movies, anyways.

Edit 2:

I calculated the internal volume, and 12"w x 12"h x 6"d seems to be me best bet. I wouldn't be able to fit that driver on a 10.5" piece of wood, the outer dimension of it is 10.6".

I'll be building this enclosure in a week or two.

 

[bobbyg2]

Sorry, but it seems like this is turning out exactly how it did last thread I made. My mom gave me permission to do this, but now that I'm ready to build the thing she refuses to give me permission. Same reason as last time, I must save up for a car. Sorry if I wasted your time, next summer when I'm out of the house for sure will I build a subwoofer.

 

[Robert_J]

I can surely understand having a project vetoed at the last minute. My wife does that to me sometimes. But it is usually a very impractical project.

Speaker building is a very good hobby. I started with my first car back in '86 and it has been going ever since. It keeps my math and geometry skills sharp. It has also taught me to use tools that have benefited me as a homeowner and the confidence to tackle most projects. For example, when we moved into this house we had to have curtains for 7 arched windows. Arched curtain rods are over $150 each (do the math!). Using my woodworking skills as well as my knowledge of the different projects I have seen on the forums and TV, I built my own. That's right, all 7 for under $50.

Just wait patiently and next year start your project. In the mean time, start watching New Yankee Workshop on PBS. You may never build a table and chairs but you will see how a professional uses his tools.

-Robert

 

[bobbyg2]

Do you know what days/times that show airs?

 

[Robert_J]

It varies by local PBS affiliate. If you have a cable box/satellite receiver/etc with an EPG (electronic program guide) just browse through the shows on the weekend. It will be there somewhere.

-Robert

 

[bobbyg2]

I think I may have convinced my Mom to allow me to build a subwoofer.

I was looking at the Dayton Reference Series HF 10" in a 5ft^3 ID enclosure, and a 240W amp.

Parts Express: Dayton RSS265HF-4 10" Reference HF Subwoofer 4 Ohm

Parts Express: Dayton SA240 240W Subwoofer Amplifier

Only thing is, how would I be able to get a 20Hz High-pass filter? It was the only way that I could get the driver to not bottom out under 20 Hz.

Here's some graphs:





Forgot to grab a snapshot of the filter, but you get the idea.

Reason why I went with a 12" x 1.5" port is to make it easier to add the port into the design. I don't even have to add the port volume into the enclosure volume. It's like having a port that sticks out of the enclosure, but building the enclosure so that it doesn't look like it is. All I have to do now is figure out the amount of space the amp and driver takes up, and how much I would have to add to the internal volume. I was thinking 1ft W, 2ft H, and 2.5ft deep and add whatever volume the driver and amp takes up to the depth of the subwoofer.

Was thinking of an enclosure somewhere alone the lines of this:




Reason why I raised my budget and went with a totally different design is because I'm planning on using this in my bedroom after I move into my own house. I'll using it for movies mainly, and the Dayton Reference HF Drivers have a pretty flat SPL response, which is what you want in a sub for movies, correct?

Thanks, Bobby.

 

[Robert_J]

The stock filter on the amp starts rolling off at 3db/octave starting at 30hz. That should be fine.

That is quite a large box for a 10" sub. I'm sure the 12" Dayton will work in it. The DVC 12" will as well and I think they are on sale.

-Robert

 

[bobbyg2]

Alright, the DVC gives just as much output, but it's not as flat (The DVC is extremely efficient, using 1/4 the power to get the same amount of output):

Parts Express: Dayton SD315-88 12" Shielded DVC Subwoofer

Parts Express: Dayton SA70 70W Subwoofer Amplifier





I think that's pretty good, for nearly half the price of the reference, I can get just as much output, just not as flat.

By the way, I tried modeling it sealed... Didn't go too great.

 

[bobbyg2]

Would the displacement of the driver and amp be enough to make a noticeable difference? Or would I be fine just building a 2'x1'x2.5' internal dimensioned enclosure and using the port size recommended by WinISD?

Edit:

I calculated that if the driver and amp took up .5 cubic feet, and I used the port size recommended by WinISD for the 20Hz at 5ft^3, it would raise my tuning to 21Hz, not making all that much of a difference.

 

[Robert_J]

I didn't mean the shielded DVC 12. The other DVC 12.

Amp and driver will take up no more than .2 cubic feet.

-Robert

 

[bobbyg2]

They must have discontinued the regular non-shielded one. I can't find it on PE.

Does it have the same specs at the non-shielded one? 'Cuz if it doesn't I'm going to need to remodel it again, and buy it from a different place.

EDIT:

Never mind, found it. Tried modeling it, with pretty good results.

Parts Express: Dayton DVC310-88 12" DVC Series Subwoofer
Parts Express: Bash 300W Digital Subwoofer Amplifier





I modeled it with a 20Hz High-pass filter.


It would work without reaching XMax at 400 watts, but there's no 400 watt amp on Parts Express.

 

[Robert_J]

I'm building a 4cf, 20hz Fb sonosub with that driver right now. It will be going into a family member's house.

No need to push the driver to its limits. You will get more than enough bass from using a 300w amp. The additional 100w (if there were a 400w amp) would be wasted because you will very rarely turn it up that loud. The difference in output would be about 1db both at full volume.

-Robert

 

[bobbyg2]

Make sure to take a few pictures of it for me, and a detailed review, to help me to determine whether I want this driver or not.

Thanks for the help.

 

[Robert_J]

It is a clone of the Adire Audio Shiva. Search the archives here for reviews. It has been a tried and true sub that was introduced about 10 years ago.

-Robert

 

[bobbyg2]

Hey Rob, do you know of any enclosure modeling software? I want to print out the plans for this because I'm going to be making the enclosure over at my uncles house (he builds cabinets, he has the tools).

I was thinking 1'W x 2'H x 2.5'D Internal chamber with a 1.5"H x 12"W x 1.7'D Port tuned to 20Hz. That should give me an internal volume of about 5 cubic feet, minus driver and amp displacement.

EDIT:

Something along the lines of this:



I may not be able to flush-mount it, but is that a necessity, or just optional?

 

[Robert_J]

Flush mounting is required on 99% of full range speakers. It is not required on subs.

Looking at your design I see a few things. First, you don't need a bend in your port. Remove the 2 pieces of wood at the end of your port. Your port will function exactly the same. Second, your measurements are for internal only. Modify them to show the length of each piece of wood used. Then download CutList Plus free version. Enter the measurements of the 7 pieces of wood that will be used to build your box. That will give you an idea of how much MDF will be required as well as the most efficient way to cut the parts.

-Robert