I need help giving the last touches to my DIY sub.

2604 Views 10 Replies 2 Participants Last post by BigLouis1971, Feb 20, 2015

BigLouis1971

Discussion Starter · Feb 12, 2015

This is my very first project and I will be using one JBL GTO1214, one 4" port tube, one 5.5 cu ft enclosure and a Behringer Inuke NU1000DSP to power two of these subs. Once finished they will measure 22"W X 22"D X 27"H each for a net volume of about 5.5 cu ft. I used furring strips 1.5" thick to hold them together from the inside because I plan to round all of the corners later and I tried to avoid to have screws too close to the edges. Due to budget limits I was able to build only one cabinet this month and will build the other one next month. The things I need help with are below:

1) due to not so precise cuttings at Home Depot, I see small gaps of about 1/16" to 1/8" at some places. The doubt here is if I can just fill those gaps with glue, caulk and wood filling without altering the sound.

2) WinISD gave me an optimal port tune of 22Hz for that cabinet volume. I already got the port and is 4" in diameter, the length is supposed to be about 10". From where to where am I supposed to measure the 10"? From just where the internal flare begins and ends? (excluding the flares) or the whole port including the outside and inside flares? I will top mount both port and driver and I don't know if I'm supposed to measure the portion of the flare that will be outside of the cabinet to get the 10".

3) I used speakon connectors and jacks to build my own cables and this is my first time I use those. I never even heard about that type of connector before. What I learned about them, I learned it online. I need help checking that I screwed the wires where they are supposed to be.

4) I noticed some hum noise in the sub and I was wondering how to avoid it.

5) I tried to test the sub with an online tone generator and is not working with it for some reason. The speakers work fine, but the sub don't. I also tried it with WinISD tone generator and isn't working with that neither. Is working fine with movies tho. How can I make it work with both online and WinISD tone generators?

6) I was hoping to find some software to measure the SPL with my USB microphone. I want to play some test tones and measure their SPL with my Samson mic. I'm not talking about REW in this one. Where can I find such software?

7) The sub is heavy and I would like ideas about how to add some wheels so I can move it easily in the case that I'm not happy with the placement. I would like nice wheels and not some ugly stuff.

That's all that I can remember for now. I assembled the sub just to see how it fits. It don't have any glue or caulk yet, just some screws. For now is sealed, I have the port but wanted to test it sealed first, also I needed to ask my questions first. There's still time to do some small changes if you suggest some.

Thanks in advance!

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chrapladm

· #2 · Feb 13, 2015

1) PL Premium glue can fill gaps very well.

Effective length is port length.

3) Do you have any pictures?

4) Hum noise can be attributed to your electronics such as your amp or AVR or possibly other electronics connected. Is everything all using the same power point? Or power strip?

5) How are you playing the tones from the generators?

6) REW is your best software to use and FREE. So once you get a calibrated mic then you go through the steps to use it with REW. If you dont have a calibrated mic then you will never know what your speakers actually measure.

7)You can always place casters on your subwoofer if you like and add a small "skirt," if you will to cover most of the caster area that can be seen. ARe you on carpet or hardwoods?

Be very cautious when playing a subwoofer in a cabinet that is not sealed. You will have lots of leaks and can potentially damage the woofer because you feel it "should be," louder.

We are all here to help so take it slow.:T

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BigLouis1971

Discussion Starter · #3 · Feb 16, 2015

chrapladm said:
1) PL Premium glue can fill gaps very well.

2)

Effective length is port length.

3) Do you have any pictures?

4) Hum noise can be attributed to your electronics such as your amp or AVR or possibly other electronics connected. Is everything all using the same power point? Or power strip?

5) How are you playing the tones from the generators?

6) REW is your best software to use and FREE. So once you get a calibrated mic then you go through the steps to use it with REW. If you dont have a calibrated mic then you will never know what your speakers actually measure.

7)You can always place casters on your subwoofer if you like and add a small "skirt," if you will to cover most of the caster area that can be seen. ARe you on carpet or hardwoods?

Be very cautious when playing a subwoofer in a cabinet that is not sealed. You will have lots of leaks and can potentially damage the woofer because you feel it "should be," louder.

We are all here to help so take it slow.:T

1) I decided for plastic wood. Here's a link: plastic wood. It can be sanded and has a color similar to MDF so I guess is pretty good to fill gaps.

2) So basically I should measure from half flare to half flare?

3) I plan to upload some pics later about the whole project to show cables, gaps, bracing, etc...

4) That's not the problem because I used power strips to hook everything, but now I moved the amp to another power outlet and is the only equipment hooked there. The problem looks more related to the fact that I used unbalanced 1/4" TS to RCA female adapters and a splitter in the receiver side. I guess I can try XLR to RCA adapters or a noise supresor.

5) Never mind, the sub is playing the tones now.

6) I don't have a calibrated mic, I have a Samson Meteor USB mic instead that is supposed to have a flat response, but reading some reviews I found out that is better to record vocals. Can I use that mic anyway? How can I use it?

7) For now I'll use short casters and place them away from the edges so they can't be seen, at least till I find a better idea.

The cabinet definitely has leaks which I hope to fill soon. I did some tests with tones and sounds a little distorted with 20 and 25 Hz tones, but seems to improve from 30 Hz and up. Any ideas about how to avoid distorted sound for 20 to 29 Hz?

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chrapladm

· #4 · Feb 20, 2015

What is this cabinet ported at or tuned to?

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BigLouis1971

Discussion Starter · #5 · Feb 20, 2015

chrapladm said:
What is this cabinet ported at or tuned to?

Is tuned to about 23Hz.

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chrapladm

· #6 · Feb 20, 2015

As soon as all leaks are fixed then you can do some listening tests. While having leaks it is going to sound horrible and not have much low end because essentially with the leaks you have a higher tuned cabinet.

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BigLouis1971

Discussion Starter · #7 · Feb 20, 2015

chrapladm said:
As soon as all leaks are fixed then you can do some listening tests. While having leaks it is going to sound horrible and not have much low end because essentially with the leaks you have a higher tuned cabinet.

I was kind of guessing that. That leaks are a hole with no control over length or diameter and was guessing that they will probably have the effect of a higher tuned port. I'm glad that you answered a future question with your post. Should I add some poly fill or do any additional small adjustment beside that one?

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BigLouis1971

Discussion Starter · #8 · Feb 20, 2015

Oh and I almost forgot. I was thinking about sealing the inside of the cabinet with paint primer. That's beside the glue, caulk and plastic wood of course. Should I go for the paint primer?

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BigLouis1971

Discussion Starter · #9 · Feb 20, 2015

I forgot another thing. I'm clueless about how to equalize the amplifier. Where can I find a tutorial about how to fine tune the DSP for a subwoofer?

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chrapladm

· #10 · Feb 20, 2015

You dont need stuffing with a subwoofer of this type. EQ will work best using REW and a calibrated mic.(MiniDSP Umik)

If you use PL premium glue you wont need anything else to seal. If using something else like you are and glue you should be fine. Primer is not going to stop anything. SO dont worry about priming the inside unless it is because you can see the inside because a port or something that bothers you and your eyes.

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BigLouis1971

Discussion Starter · #11 · Feb 20, 2015

Too bad I didn't knew about the PL premium glue before because I already got some Titebond III glue and caulk to seal the leaks. I hope that's enough to seal the internal leaks and that the plastic wood is enough to fill the external gaps. Maybe I'll use the PL premium glue for my next cabinet.

I'll drop the idea of the primer but what I do need to paint is the inside of the port. The port has some white PVC pipe attached to black internal and external flares and it came that way from the store and yes the white part of the port kinda bothers me so I'll paint it.

I don't have a calibrated mic yet. All I have for now is a Samson Meteor mic. Maybe I'll get the Umik or Dayton Audio mic in a few months. I was hoping to be able to calibrate the Samson Meteor for now. Do I really need a calibrated mic to be able to use REW or can I calibrate anything else? There's no way to calibrate the one I have?

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