# NOOB subwoofer questions



## CortGideon (Jul 19, 2012)

Hi,
Been on google for the past couple of days and spent hours and hours trying to find answers and somehow wound up here. I have never built a speaker or sub-woofer before but somehow got it in my head to try... saw a cool thread by Mike on here with his Quartet10.

I have a limited budget and am looking to build a 10 or 12" subwoofer. My first thought is to Frankenstein some parts together. I have an old ported 12" subwoofer box I used for my car just lying around. Was going to start the first one using that.

I'm looking at a Dayton Audio amp (100 watts) and some used 4 ohm car drivers. Would this work? I have heard mixed reviews about using car subs. Does it matter? 

Doing research, here in Canada, I have found Creative Sounds, Solen, and Q-components. Any other places that sell sub amps and drivers? Any recommendations? My second thought is to start from scratch and build a small sealed cabinet...


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## fusseli (May 1, 2007)

Welcome to HTS!

Repurposing an old box and using a conservative 100W amp sounds like a great starter/learning project. How big exactly is your box? We will happily help you model a subwoofer so you get the best results. It depends on what you want to get out of it. Many people skip the learner project and dive right in to spending hundreds.

I would advise against using a _cheap_ car audio sub for your build, you will get better results with better drivers whose purpose isn't to look flashy. Look around on partsexpress.com and and see what you can see, the Dayton Classic and SD subs are affordable and would be a great place to start. Otherwise Creative Sound Solutions there in Canada would surely be a good way to go.


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## CortGideon (Jul 19, 2012)

Thanks for the reply.... After some consideration, half the fun seems like building the box!! Maybe I will start from scratch after all (still limited budget). 
Since I found this site through the Quartet 10 from CSS, maybe I'll save a bit and get the SDX10 driver. I went to their datasheet and it says 24 litres stuffed for sealed enclosures. Is that the volume the box needs to be? If so, how do I get my measurements?

My idea is to build a downward facing subwoofer with the driver hidden. I saw the cutout dimensions for the Quartet being 18x18x18.... Would it be the same for just this driver?

So... I was thinking of having it 20 in height, 18 wide and 18 length. I want a 18x18x18 cube to be 2" off the ground, and the driver pouding against the MDF on the bottom.... Don't know if this makes sense of of if I can post links yet...


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## CortGideon (Jul 19, 2012)

Okay clamps and glue, got it.... thanks guys.

Any tips on how to cut a hole for the driver? I don't have any fancy saws so I'll have to borrow or rent something. Also I see some people have a nice groove in the wood where the screws are inputed for the driver. How do you do this? Do you put something in between the wood and the driver like rubber or???


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## caper26 (Sep 10, 2010)

You can use a jigsaw, cut inside the circle so the hole is slightly smaller than required. Then sand out the hole until the driver fits. Did you visit the threads i mentioned?


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## dboff01 (Feb 16, 2010)

caper26 said:


> You can use a jigsaw, cut inside the circle so the hole is slightly smaller than required. Then sand out the hole until the driver fits. Did you visit the threads i mentioned?


You can visit my build thread in progress for general building tips including some of the mistakes I made.

http://www.hometheatershack.com/for...jects/58840-epik-15-diy-ported-subwoofer.html


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## CortGideon (Jul 19, 2012)

Looked at your pics... badass!! I wish my woodworking skills were good enough for that design but unfortunately not yet....

How did you get the groove in your baffle for the driver to slide in? 

Will read thread in detail later... lots of cool threads including Capers! 

Also, I will be trying the " + " shape for bracing. Do I need bracing to touch all 6 sides of box or can I just have that shape touching 4 sides...


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## dboff01 (Feb 16, 2010)

CortGideon said:


> I wish my woodworking skills were good enough for that design but unfortunately not yet....
> 
> Read more: NOOB subwoofer questions - Home Theater Forum and Systems - HomeTheaterShack.com
> 
> ...


Regarding woodworking skills, I never built anything like this before so don't necessarily sell yourself short. It is also not fully finished so the jury is still out on how respectable this thing will end up looking.

The recess for the driver is created by the use of two pieces of 3/4" MDF for the front baffle with two different diameter circle cutouts. The inner circle has the smaller diameter so the driver can mount to it, the outer circle has the larger diameter to surround the face of the driver.

Bracing is a bit of an inexact science but most follow some rules of thumb or just copy what they've seen from other builds.


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## BillCinLR (Sep 24, 2009)

Cort,

Try looking here for help ... you can buy pre-cut subwoofer enclosures (Round cut-outs and all).

http://www.diysoundgroup.com/flat-packs-1.html

Bill C


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## CortGideon (Jul 19, 2012)

Thanks for this... I'm quickly realizing the cost of acquiring new/used tools is getting to be quite high. Home Depot was selling clamps (24") for $30 a piece. yikes.... 

Does anyone know of a place in Canada that does this? Scared to see shipping costs from Ohio but maybe I'll inquire... thanks!


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## caper26 (Sep 10, 2010)

canadian tire had mastercraft clamps last week on for 17. I bought 2 more. If I were you, I would go to flea markets, check buy& sell, put want ads out for used ones or borrow some.


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## CortGideon (Jul 19, 2012)

caper26 said:


> canadian tire had mastercraft clamps last week on for 17. I bought 2 more. If I were you, I would go to flea markets, check buy& sell, put want ads out for used ones or borrow some.


Good idea.. flea markets...cheap cheap cheap! Especially for clamps.

Hey guys, I may just get the kit. How do I figure out if this driver:
http://www.creativesound.ca/details.php?model=SDX10

Will be right in this kit:
http://www.diysoundgroup.com/flat-packs-1/1-25-sub-flat-pack.html

The driver has to be rated for 1.25 cubic feet right? Is that how you tell? Does it matter if its not exact? I see the inner baffle is 9.4" so I could always sand it down if the driver only need 9" right?


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## BillCinLR (Sep 24, 2009)

Cort,

You are thinking about putting a 9" peg into a 9.4" hole! The hole is already TOO BIG. While the driver will certainly fit into the hole, there MAY not be enough material to drill holes for the screws/bolts to hold it to the enclosure.

Again ... Good Luck,

Bill C


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## CortGideon (Jul 19, 2012)

BillCinLR said:


> Cort,
> 
> Try looking here for help ... you can buy pre-cut subwoofer enclosures (Round cut-outs and all).
> 
> ...


Contacted this guy twice now... no response. Do you know if he's still in business? Any leads to something like this in Canada? Having a hard time getting the cabinet off the ground.


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## GranteedEV (Aug 8, 2010)

CortGideon said:


> Contacted this guy twice now... no response. Do you know if he's still in business? Any leads to something like this in Canada? Having a hard time getting the cabinet off the ground.


Erich H wasn't really in the business in the first place. Just hobbyist doing this in his free time and not really turning any profits. If he doesn't respond to your emails just try sending them again - he gets around 200 emails a week and that's simply difficult for him to keep up (he focuses on keeping up with orders rather than emails). 

If you order via the website you should be able to get it shipped within a few days though. He said he's going to set up the alternative shipping today if he can.


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## CortGideon (Jul 19, 2012)

Well I wanted to buy something but have him mod a design a bit... he didn't respond back. I asked about freight to Canada too (31 lbs could be pricey). No response...

If he gets that many emails, he should think about hiring someone and indeed, make a profit


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## CortGideon (Jul 19, 2012)

Wow.... this project is really hard to get off the ground. I've tried emailing that Eric H guy 4 times now lol....

Anybody in Canada willing to make me a flatpack? I'm sure we can arrange something? 

I went and even put an ad on Craigslist and the cheapest quote was $150 for that same flatpack he's got for $52 :yikes:


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## CortGideon (Jul 19, 2012)

Finally got a sub and amp.... I noticed there are 2 "tabs" on back of driver for + and 2 for -. My amp only has 2 wires coming from it. Does it matter which tab I connect to or should I "jump" them so they're continuous?


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## caper26 (Sep 10, 2010)

yes it matters, + is positive, - is negative. connect them to the matching leads (the leads are the wires coming from the amp)


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## GranteedEV (Aug 8, 2010)

CortGideon said:


> Finally got a sub and amp.... I noticed there are 2 "tabs" on back of driver for + and 2 for -. My amp only has 2 wires coming from it. Does it matter which tab I connect to or should I "jump" them so they're continuous?


If I'm understanding correctly, The driver is probably DVC (Dual Voice Coil) if it has two speaker wire inputs. That said I don't think the SDX-10 should be DVC so I am a bit confused. Anyways there are three different ways you can wire such a sub.

One Amp per Voice Coil. - Generally presents a 2 or 4 ohm load to two separate amplifiers. Only useful if you don't have a better way to get mono bass or if you just feel like splurging on amps.

Voice Coils in series. Generally presents double the above load - so 4 or 8 ohms - to a single amplifier. Maximized voltage input as home amps are generally more comfortable into higher impedances. Go 

Wire:

Amp Positive --> Positive A
Negative A ---> Positive B (using a short piece of speaker wire)
Negative B ---> Amp Negative

Voice Coils in Parallel. Generally presents half the above load - so 1 or 2 ohms. NOT recommended for most amplifiers. .


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## CortGideon (Jul 19, 2012)

I got a TRIO12. I don't know if I see any A/B ... how do I tell which is which? It's just positive and negative, each with 2 tabs/connections.


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## caper26 (Sep 10, 2010)

Oh, i know what is going on. There are 2 tabs for each terminal, 90 degrees just for installation needs or wiring options. 2 facing out, and 2 facing to the sides , like this:

_l l_

The 2 tabs on each side are THE SAME


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## CortGideon (Jul 19, 2012)

Yea that sounds about right... I can't find any differentiation between them so I guess they're the same. Same piece of metal. So I take it as long as I hook up + to + and - to - I'm good right?


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## caper26 (Sep 10, 2010)

yes that is right. I have a TRIO12, same lead on both sides. thats it


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## CortGideon (Jul 19, 2012)

I have a sealed box but I'm hearing I may not have made the best choice. And its my first so it will probably sound a bit off. Do you have ported?
What happens if there is space in between the wood panels? I think the guys gut my wood crooked lol. I may use filler....


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## caper26 (Sep 10, 2010)

sealed is fine as long as the volume is correct. Out put will be less but curve will be flatter down low. I would need pictures to see what you are talking about. there cant be any gaps at all... sealed is SEALED


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## CortGideon (Jul 19, 2012)

I will get pictures up soon.


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## CortGideon (Jul 19, 2012)

How long should my pipe be for the PORT? I got a flared one... It says to cut down to appropriate length :help:

 

So I screw one side in, then how long should it be inside the cabinet? Do I attach the second piece of flared port onto the piping, inside the cabinet or no?

My sub is 20" high by 18" x 18".... Well it's like an 18" cube pretty much, just 3" above ground (with feet). Please see photos below.


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## CortGideon (Jul 19, 2012)

So my first attempt at making a cabinet. Woodworking skills a bit rusty :huh:

 

Put 2 braces... One a cross touching North/South/East/West and the other N/S.

 
Coat # 2 of appealing time red!


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## BD55 (Oct 18, 2011)

CortGideon said:


> So my first attempt at making a cabinet. Woodworking skills a bit rusty :huh:
> 
> 
> 
> ...


Is that the final placing of your bracing as shown in your second pic? If it is, I would change your bracing layout. You want to eliminate vibrations of the panels, so your best reinforcement is at the center of each panel (5 sides at least, the baffle side obviously is taken). Essentially you want to tie all the sides together at at least at the midpoint of each panel, and because you can't tie the side with the driver to other sides, you usually make it double or even triple thick.


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## CortGideon (Jul 19, 2012)

Yea that's final... I think it sounds alright right now but then again, I have nothing to compare it to lol.

I've been discussing making a ported cabinet with Mike P so I may build a ported one, or have one built for me. This may become a piece of furniture


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