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Old 7th June 2004, 09:13 AM   #1
S.C is offline S.C  United States
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Default My almost finished sub

Since no one appear to answer my questions in my last post "Will snontube sub work in a car", I am posing this new one for additional questions about the sub.

Ok let's look at some pictures first:
This is a shot of the sub placing vertically

Click the image to open in full size.

This is a left 45 degree angle shot of the sub

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This is the shot of the Speaker Binding post, the innner sub cap
with 5/8" thick wall on the out side parameter.

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The Tube inside

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All the components for my sonotube

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The inner sub inplace

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The outer sub and the 5/8" ring gap+gasket

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The Gasket ring inplace

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8 10-32 X 3" machine screws and the screw driver

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the end cap

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This is a side shot of the ring gasket and the 5/8" thick wall.

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This is a shot of the binding post and the outer sub with screws

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The end cap shot

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The right 45 angle shot of the sub

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The shot from the top to the outer sub.

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NowI have a few important questions about sub parallel connection, amplifier and finishing.

1. Is "wire the drivers out phase" means parallel connect it?
2. If it is true, will it make both drivers become a 2ohms load instead of a 4 ohms load in each sub? I saw the commerical product Bazooka RS804DV said that parallel connect two 4 ohms will become a 2ohms which the amp I ordered can't handle under bridge mode. If all this is true, why noone had ever mentioned it before I traped myself into this mess, even in my last post?
3. Since I can't cancel the order in overstock.com, shold I return it and get a real sub amp, or stick with it and connecting those two driver seperately that Right channel to one driver and the left to another. Or I should reconstruct the enclouse to a single driver sonotube which is the cheapest way and a bigger tube.
4. If I can keep the sub as it is now, how can I make a durable black finish, or a silver finish which looks like aluminum. Which color will you guys prefer? I want it to be durable becase it is going to be in my trunk. I know putting ferbric will be the most durable, but I want some gloss look.......

There are a lot of questions, and I'm appreciate your time. Plz help, and enjoy the pictures.

P.S: Haha,my sub looks like a war head, or grabage can with cover on, and the war head will install to my car. I'm think what will the policeman react when he stops me and see this warhead like sub in the car
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Old 7th June 2004, 09:38 AM   #2
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I did not read your other post (your link does not work), but I can answer a couple of your questions.

1. Wiring one sub out-of-phase means to just reverse the polarity when connecting one of the subs. That way, they will both be moving in the same direction, relative to each other.

2/3. You are correct about connecting two 4ohm subs parallel will equal a 2ohm load. Since your amp won't be stable at 2 ohms, I would just wire them separately to the left and right channels.

4. I don't know. Sorry.

Hopefully that helps some. Good luck!

--Ferdi
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Old 7th June 2004, 02:46 PM   #3
S.C is offline S.C  United States
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Quote:
Originally posted by ftjandra
2/3. You are correct about connecting two 4ohm subs parallel will equal a 2ohm load. Since your amp won't be stable at 2 ohms, I would just wire them separately to the left and right channels.
Thx, Ferdi. They are useful comments that I am looking for, but I still worry about the sound it will put out. So I have some more questions come to my mind. Eventhough there are more questions, I confrimed the 4ohms to 2ohms thing at least. Man, nobody in any sites have ever metioned it before untill I looking for an answer of how to connecting car amp to subwoofer in some other forum, and I' got into this mess now.

Beside the benefit of I don't need to return this amp, are there any benefit of connecting the amp this way?

If Left channel and Right channel push to each other, will I get the same result of connecting it out of phase?

Will it eventrually blend the sound together since the drivers are so close to each other, and the car is so much smaller than a room?

How about the cone which is out of the box, it will produce a much clear sound whatever channel it is than the cone inside, right? Will this setup sound bad?

Everyone plz help! I still have the 2/3 undecided yet, and i need your input.
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Old 7th June 2004, 03:41 PM   #4
azira is offline azira  United States
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1) Wiring out of phase simply means that one sub connects the + terminal to a signal and the other sub connets the - terminal to a signal. You do this in parallel or series.
Either way you would do the same as if you were going to parallel or series the speakers and then reverse the connections on one of them.

2) If you wire them in series, you'll have 8 ohms which your amp can handle. No one "told you abou this mess" because probably we assumed you'd understand it. Car audio people wrestle with this kind of thing all the time.
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Old 7th June 2004, 04:37 PM   #5
dhenryp is offline dhenryp  United States
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Looks good. I'm assuming you have figured out that the volume in the tube is enough to support the two drivers with whatever response you are looking for.

The only thing that cponcerns me is the way you have attached the plates to the tube. You are putting wood screws through the cardboard into the edge of e realtively small section of MDF. The combination doesn't give much holding power. At the very least. secure the endcaps to the tube using construction adhesive (Liquid Nails at Home Depot). This will also ensure a tight seal. Don't forget to scrape off the wax on the inside of the tube.


Even better would be yousing the glue AND replace some or all the bolts holding your drivers to the endcaps with threaded rods going the length of the tube. That way you can connect the front and back drivers together and you will never have to worry about blowing out your endcaps (speakers maybe, endcaps no). You might have to do something to prevent the nuts from crushing the rim of your drivers. Something like this might work:

Part Number 95305A540

http://www.mcmaster.com/

I'm sure you can come up with cheaper options.

If you want the finsh to look like aluminium, you could consider aluminium. A relatively thin sheet should bend around the tube pretty easily.
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Old 7th June 2004, 07:00 PM   #6
S.C is offline S.C  United States
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Quote:
Originally posted by azira
2) If you wire them in series, you'll have 8 ohms which your amp can handle. No one "told you abou this mess" because probably we assumed you'd understand it. Car audio people wrestle with this kind of thing all the time.
It is my fault to make you guys think that I know about this stuff, but the fact is I'm just a noob, and this is the first speaker I build.
If it will become 8Ohms, will the amp I had ordered have enough juice to drive this sub? Although I know it won't, what happen after the resistern increase. Will it bring up the power requirment to drive this sub too? If so, will it be still worth it to keep this amp, or sub enclouse?

Quote:
Originally posted by dhenryp
Looks good. I'm assuming you have figured out that the volume in the tube is enough to support the two drivers with whatever response you are looking for.
Yes, but I have a question about stuffing. Will it the volume that I calculated in some speaker calucator include the stuffing? I thought stuffing is not nessary before, but I found out I was wrong recently.

Quote:
The only thing that cponcerns me is the way you have attached the plates to the tube. You are putting wood screws though the cardboard into the edge of e realtively small section of MDF. The combination doesn't give much holding power. At the very least. secure the endcaps to the tube using construction adhesive (Liquid Nails at Home Depot). This will also ensure a tight seal. Don't forget to scrape off the wax on the inside of the tube.
Thx for reminding me about the wax inside. I understand the nails won't do much, but I don't understand what u mean by securing the endcaps to the tube using construction adhesive (Liquid Nails at Home Depot). I had already use wood glue, Silicon xxxxx(forgot the spelling), and the nails to hold this inner cap already. So where do you put those Liquid Nails at? T-Nuts? the Nails, or the screws?
Quote:
Even better would be yousing the glue AND replace some or all the bolts holding your drivers to the endcaps with threaded rods going the length of the tube. That way you can connect the front and back drivers together and you will never have to worry about blowing out your endcaps (speakers maybe, endcaps no). You might have to do something to prevent the nuts from crushing the rim of your drivers. Something like this might work:
I had thought about that too. I may use like 8 wooden square stick connecting the top endcap t-nuts to the other end. I think the construction of a drum will have some good idea of how to build a cylinder enclouse.

Quote:
If you want the finsh to look like aluminium, you could consider aluminium. A relatively thin sheet should bend around the tube pretty easily.
After I thinking about the look, I think I will go back to black paint finsih. The Aluminium sheet finish will make the sub wierder ! haha. Thx for the suggestion thou. You know what, I had thought about the stuffs that ppl spray on their back of the truck which is really durable, but those stuffs are expensive.


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Old 8th June 2004, 01:11 AM   #7
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www.jlaudio.com has wiring tutorials.
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Old 8th June 2004, 01:46 AM   #8
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Default Open now if U used silicone

If you used silicone to seal it and you didn't wait for it to cure for at least 24hrs (more if it's thick) before mounting that interior driver, you need to immediately go open it up. Silicone releases an acid as it cures that will settle on any metal it can find. Don't find out the hard way a few months later like I did on one of my first projects. That acid will ruin your driver.
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Old 8th June 2004, 02:53 AM   #9
S.C is offline S.C  United States
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Default Re: Open now if U used silicone

Quote:
Originally posted by johninCR
If you used silicone to seal it and you didn't wait for it to cure for at least 24hrs (more if it's thick) before mounting that interior driver, you need to immediately go open it up. Silicone releases an acid as it cures that will settle on any metal it can find. Don't find out the hard way a few months later like I did on one of my first projects. That acid will ruin your driver.

You scared me! I rushed to open it up and the driver is fine I used Siliconized Acrylic caulk, and it didn't seat for 24hrs before I mounted the driver in. Anyway it is ok, I'm grad that.

bhg41088- thx for the wiring.

Ok, I finally decided 3 best solutions, 1: The cheapest way change the enclouse, 2: The most expensive way return the amp and build another one, 3: Test how the amp sound before I do anything.
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Old 8th June 2004, 03:02 AM   #10
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Glad to hear all is OK. Whenever I see silicone, I remind people not to make the mistake I did.

Give it a listen first. If the amp accepts 4 ohms on each channel you're home free. Assuming you head unit has a sub out, just split the signal with a Y plug (at the amp so you only run one wire to the trunk). You can't send a stereo signal (left and right) to the drivers. They must have the same signal since it's isobarik.

Listen at low levels first. If it sounds bad, something is wrong.
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