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Want to build my own sub... some advice needed. (im a NEWB) (1 Viewer)

Anthony_I

Stunt Coordinator
Joined
Sep 9, 2003
Messages
177
Ok i will be using a rhythmik audio plate amp to power the sub, and it will be running from a Pioneer XV-HTD520.

Now here is my problem, if im going to build the sub (and the rest of the speakers) im naturally assuming that i should buy speakers that match the frequency response of my unit.
IE the sub channel on my unit has a response range of 30Hz - 2000Hz. I want to use a Phoenix Gold Octane R12d as the speaker for my sub. But ill be damned if i can find out what the response range of that speaker is... and the only place by me that i knows sells them wont fucking tell me cause "it doesnt really matter"

well to me it does. I've fallen in love with this speaker, the way it sounds, and looks.... its all flashy and shit lol. but i dont want to buy it if its freq response is going to be like 40Hz - 160Hz, cause then i would be missing a whole lot wouldnt i?

So what kinds of things do i need to know to build a sub and speakers for my unit.
and can ANYONE find any info about the freq. response of said speaker?? cause i cant find shit.
 

Rory Buszka

Supporting Actor
Joined
Jun 5, 2002
Messages
784
(black guy from Spaceballs): "Maaannn, we ain't found s***!"

Here's how it is, yo
Get a good driver, like a Dayton Titanic from Parts Express. Get the 12". I know it's like $150, but you have to shell out to get the performance, yo. With the Rhythmik amp, you should have plenty of power. Put the driver in a box with a big 4" flared port and you should be in business. To see how big the box will have to be, download WinISD from http://www.linearteam.org (not the Pro, because it is really technical for someone who is new to all this.) Once you have WinISD on your computer, go to the Utilities menu and select Database Maintenance. Click New and type Titanic Mk II 12" into the very top entry field. Then pull up the Titanic driver on http://www.partsexpress.com/ and input its electro-mechanical parameters (Qts, Vas, Fs, Qms, Qes, Z/Impedance, Re/Voice Coil Resistance) into the spaces below the input field. Make sure you get the units straignt or your box will not work. You can change the units by clicking on the unit symbol beside the entry blank. This will convert units on the fly. Then click OK. Now WinISD knows how to model enclosures with that particular driver. Close the Database Maintenance window. Click on the New button in the toolbar and choose to design an enclosure with oen of your own drivers. Select the Titanic from the list and click Next. As the program guides you through the next steps before you get to the response graph, enter that you will only be using one driver in Normal configuration, and that your driver will probably work with both a vented and a sealed box. Ported boxes will have more output, and sealed boxes will have better transients and be more tuneful, but you can't drive them as hard as you can a vented box. Once you get into the project window, and the frequency response curve appears on the graph, then switch the units on box volume to cubic inches. This makes it easier to model. Go into your Calculator and pick some dimensions that give you a box with an internal volume of right around two cubic feet. Then go into the ports section and change the units for the port size and length to inches and enter that you will be using a 4" port. Once you have a good frequency response curve (no peaks or dips greater than +/-3dB) and a bass cutoff point (where the graph crosses the purple line) that you like (shoot for 20-25 Hz) then you can write down the dimensions of the box and buy the parts. From Parts Express you will want to get the sub (Titanic Mk II 12") and the port (4"-Diameter Precision Port) and then you can build the box. Use graph paper to design the actual enclosure using the dimensions you came up with while entering volumes into WinISD to try them out.Make sure you figure all the panel dimensions properly. If you have no experience with woodworking then find someone who does and at least get them to help you. Build the box out of MDF (Medium Density Fiberboard) that is 3/4" thick or greater. MDF is the most acoustically-dead wood for building speakers, so you won't gat nasty panel resonances. Make sure to build an internal brace that will keep the walls rigid under bass transients. When you cut the panels for the enclosure, measure very precisely. Then when you put them together, use both screws and Elmer's Wood Glue in the joint for a very tight hold. You can use a jigsaw for cutting the driver hole and port hole. This is important for a good subwoofer. You can use a jigsaw for cutting the driver hole and port hole. At this point you should paint or otherwise finish the enclosure if you want to. This is the point during the construction at which it should be done. Following the instructions in the Precision Port package, cut the port tube to the appropriate length and attach the flares as directed. Install it in the box. Also in the box, line the walls with some damping material. Fiberglass insulation will work ok for this. Try to make sure that the material is not so close to the port that a big bass transient won't rip off little pieces and eject them through the port. There might be people walking barefoot around this sub and if you know what it's like to get fiberglass stuck in your hand you know that it's important to keep people from coming in contact with the fiberglass. The last thing is to install the driver using T-nuts and machine screws, which are available from Parts Express in their Cast-Frame Driver Mounting Kit. Ordinary screws will pull out of MDF when the cone recieves a big input signal. Once the driver and port are installed, then you are ready to go subwoof. Invite some friends over. They'll all think that it is the s***!

If all this seems a little involved for your newbieness, Parts Express sells kits and enclosures that will work with the Titanic and still give good results.
 

Anthony_I

Stunt Coordinator
Joined
Sep 9, 2003
Messages
177
what did i do wrong? i wasnt being rude was i??
If i was i didnt mean for it to sound that way.
 

Jack Gilvey

Senior HTF Member
Joined
Mar 13, 1999
Messages
4,948
You weren't rude, we just try to keep the level of discourse well above that of the various car audio boards...of which I'm sure you're a member.
 

Rory Buszka

Supporting Actor
Joined
Jun 5, 2002
Messages
784
That Phoenix Gold sub is designed for car use where the cabin gain phenomenon boosts the bass. In a house, you don't get that extra bass boost and the Phoenix Gold will not work real well. Get the Titanic instead. You will be mich happier.
 

Frank Carter

Screenwriter
Joined
Mar 12, 2002
Messages
1,187
Do you have the T/S parameters of the Phoenix Gold sub? If not, try and get them from PG. This will help find out whether the driver will be suitable for home use.

Like Rory said, it probably would be better to go with a driver intended for home use, see if you can sell the PG and check out drivers from companies like Adire Audio, Stryke, Dayton(partsexpress.com), Blueprint(audioliquidators.com).
 

TimForman

Supporting Actor
Joined
Dec 4, 2002
Messages
847
we just try to keep the level of discourse well above that of the various car audio boards
Thank you Jack and Pat. I get pretty tired of that....uh, stuff too. I would second the Blueprint drivers if you can get one. For a first sub it's a serious bargain.
 

Anthony_I

Stunt Coordinator
Joined
Sep 9, 2003
Messages
177
Yeah i just bought the speaker tonight, i was told by a damn smart guy at the shop that it would work with my home stereo, and be good for it, but i would require a larger box to get the same sound out of.

PG reccomends a 0.9 Cu. Ft box, so how much larger should i go?

and yes i have the T/S.

And from now on i will do my best to respect others on the board and tone down the language.
 

Dan Hine

Screenwriter
Joined
Oct 3, 2000
Messages
1,312
so how much larger should i go? and yes i have the T/S.
Post the TS specs and someone will help you. Honestly, from the PG stuff I've seen I would return it and get whatever one of us suggests here...but I'll reserve my final opinion until I see the TS parameters.
 

Anthony_I

Stunt Coordinator
Joined
Sep 9, 2003
Messages
177


It will work, though without a box it barely makes any noise at all when hooked up to run at 8 Ohms, also my amp is only outputting 114W to it.

it will work much better when my plate amp arrives and its all in a box. then it will run at 250W like its supposed to.

I paid wholesale for it, $139 CAD.

As for the T/S Params, here they are

Code:

 Octane-R12d
 T/S Parameters
 Fs . .23.640 Hz
 Re . .7.24 Ohms
 Qms . .8.190
 Qes . .0.499
 Qts . .0.470
 Vas . .117.7807 liters
 Mms . .135.9013 grams
 Cms . .318 uM/Newton
 BL . .8.6628 Tesla-M
 SPL . .91.74 dB
 Sd . .511 sq cm
 Xmax. .25mm Point to Point


Thats the specs of the speaker.
 

Brian Bunge

Senior HTF Member
Joined
Sep 11, 2000
Messages
3,716
It looks pretty good in a 3ft^3 sealed enclosure or about 4.5ft^3 ported, tuned to 20Hz. I think the Xmax is a little low though. I think a Shiva would be a much better choice and could be purchased from Creative Sound for only $35 CAD more.
 

David Giesbrecht

Second Unit
Joined
May 28, 2001
Messages
306
If the shiva is 30mm point to point and this sub is 25mm point to point how much difference is that 5mm's going to make in the real world? Just wondering.
 

Brian Bunge

Senior HTF Member
Joined
Sep 11, 2000
Messages
3,716
Well, for one thing, we don't know for sure if the PG driver truly has a 12.5mm Xmax or if that is actually the limits of the driver's suspension. If it's latter, then that would mean that Xmax will more than likely be substantially less.

For $35 CAD more you would at least know what you're getting.
 

Anthony_I

Stunt Coordinator
Joined
Sep 9, 2003
Messages
177


Sounds good, but how exactly do you come to that conclusion, and what difference in sound exactly would it make to go from 0.9 Ft^3 to 3Ft^3, and how is sound affected by a port/tuning frequency? (ive never understood this "box tuning frequency" thing)
 

Anthony_I

Stunt Coordinator
Joined
Sep 9, 2003
Messages
177
also i had it hooked up out of the box, and running at 2 Ohms to test it, cause apparently running it at 8 Ohms unpowered doesnt provide enough wattage to drive it... now it sounds alright (obviously a box is needed) but after certain volume levels i can hear the speaker cut out, and my stereo makes a "click" noise like relays kicking in, im guessing this is the protection circutry kicking in from overloading breifly, and/or the speaker bottoming out?? cause no sound comes out of the speaker when this happens. and that this wont happen in a box.
 

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