DIY SUB. I got the amp, I got wood(you can laugh), opinions on whats next?

polkanddie

This is my amp, Just got it in a trade. Dayton HPSA500 500W Subwoofer Amplifier. I was thinking about changing it up and using a dual 2ohm woofer, either a kicker L5, Infinity Kappa, Or possibly a Polk?? Any thoughts...

Face

What's your budget?

How much space do you have for an enclosure, etc...?

kawizx9r

Don't think about how much 'wood' you currently have, you can and should always get more at your local Lowe's or Home Depot or any other lumber provider if you need more of it. I say this because depending on the type of driver you pick up, you might need a large/medium/small box given the drivers T/S parameters. Click the subwoofer link in my signature to get an idea of a few things you'll need along the way. The guys here at CP have been way more help to me than the other forums I've tried so look forward to that

Anyway you go with it, best of luck!

-Freddy

Face

I hope you're using either MDF or Baltic Birch.

kawizx9r

Face wrote: »

I hope you're using either MDF or Baltic Birch.

+1
Almost forgot about that!

I used MDF for mine (3/4" thick), and it was only 27 bucks for a 4' x 8' board. In fact I still have a 2' x 4' piece left (used half of it for my oversized subwoofer).

zingo

What about a Focal W cone driver? If you could find a good price on one, I feel like it would be the most accurate and musical subwoofer around.

Face

zingo wrote: »

What about a Focal W cone driver? If you could find a good price on one, I feel like it would be the most accurate and musical subwoofer around.

They're nice if you don't mind paying $750 each.

polkanddie

Oh wow, that would be nice. This is going to be a low budget project though...Most likely going to find a driver on ebay or CL. I am using 3/4'' mdf, Also this is going to be mainly an HT sub. Has anybody tried the whole passive radiator option before? It looks complicated... anyways, I have an old qlogic I was going to use the ports out of it, or at least the flared ends, would it be easier to just make a slot port?

polkanddie

Also I wanted it somewhat compact, I was thinking an 8" or 10", but definitely something that can handle a good 250 rms without a sweat.

kawizx9r

polkanddie wrote: »

Also I wanted it somewhat compact, I was thinking an 8" or 10", but definitely something that can handle a good 250 rms without a sweat.

Like I said above, I think you're looking past a few important things. If you want the sub to work properly and give you the bass you crave, set it up right. All subs are different, and going from a slot-loaded enclosure/ported enclosure/sealed enclosure will yield different sized enclosures. It's not just building a box, putting a port/hole in it and calling it a day. Take it 1 step at a time.

-Freddy

P.S. My sub cost less then $240 to make, not saying its something you can do using the same box-dimensions unless you got a deal on the same driver I used. Just make sure to do it right and you'll be very pleased. I know I am

kawizx9r

One last thing, here you go. An enclosure volume calculator - http://www.hometheatershack.com/forums/enclosure-volume-calculator/

Talk to someone that has WinISD as well, such software can help you find out what port lengths/diameters/etc. are needed to achieve certain frequencies given said driver/amp.

Face

Here's a nice sub that doesn't require a huge box.

http://www.madisound.com/catalog/product_info.php?manufacturers_id=183&products_id=8535

zingo

Can't go wrong with Seas!

Face

zingo wrote: »

Can't go wrong with Seas!

I have a pair of these that will be going into my HT soon. http://www.madisound.com/catalog/product_info.php?cPath=45_228_258&products_id=822

zarrdoss

I have the same amp and paired it with a 15" 4 ohm kicker comp vr in a sealed box. it sounds great.





http://www.polkaudio.com/forums/showthread.php?t=85249

polkanddie

Ok, I was on newegg this morning, saw what looked like a deal on a 10" Polk DB series sub, guess what 270w rms and 540w max.... same as my amp. Single 4 ohm voice coil. Looks to match up perfect. It was 29.99 shipped. I dont think you can beat that.... here are the specs.... General
Brand Polk Audio
Model db 104
Type Subwoofers
Component
Subwoofer Size 10"
Cone Material Dynamic Balance Polymer Composite dish cone
Surround Material Santoprene surround
Voice Coil Single
Voice Coil Construction 2" Diameter Double venting of the 4-layer Kapton Voice Coil
Damper (Spider) Fire-retardant flat NOMEX Spider
Specification
Peak Power 540W
RMS Power 270W
Frequency Response 28 Hz - 200 Hz
Sensitivity 86 dB
Impedance 4 Ohm
Crossover Point 37 Hz
Thiele/Small Parameters Qms: 7.0, Qes: 0.62, Qts: 0.57, Vas: 0.85 cu. ft., Sd: 54.25 sq. in., Xmax (linear): 0.3 inch, Xmax (mechanical): 1.0 inch, Le: 1.85 mH
Mounting Depth 6.25"

Any suggestions about box dimensions with this info.

amp info is ...
High power class AB output stage
Patented tracking downconverter power supply
Full parametric bass EQ
Phase reversal switch
Advanced soft clip circuitry
Toroidal power supply transformer
Auto On/Off
Power output: 273 watts RMS @ 8 ohms, 540 watts RMS @ 4 ohms
S/N ratio: 98 dB (A weighted)
Crossover: 30 - 200 Hz, 24 dB/octave
Dimensions: 11-15/16" W x 11-15/16" H x 5-1/4" D...

And I realize I may have made a booboo.... It seems I may have too small a sub...

polkanddie

I swear I saw 240 rms at 4 ohm on the manny.... let me go find that thing.

polkanddie

kawizx9r wrote: »

One last thing, here you go. An enclosure volume calculator - http://www.hometheatershack.com/forums/enclosure-volume-calculator/

Talk to someone that has WinISD as well, such software can help you find out what port lengths/diameters/etc. are needed to achieve certain frequencies given said driver/amp.

Sweeeet thanks dude.

kawizx9r

polkanddie wrote: »

Sweeeet thanks dude.

No problem, and with WinISD + T/S parameters you posted above you'll find out exactly what type of enclosure will work out for you. It'll also give you expected frequency response/etc.

I'm getting output down to 18hz from my DIY subwoofer

-Freddy

PS I wouldn't mind grabbing that 500 watter from you, my amp is actually a 250w rms model@4ohms not 240w.

polkanddie

Ok, so what does it mean when the website says rms and the manual that came with it says 273max at 8ohms and 540max at 4ohm.... thats kind of misleading if its the latter...

kawizx9r

polkanddie wrote: »

Ok, so what does it mean when the website says rms and the manual that came with it says 273max at 8ohms and 540max at 4ohm.... thats kind of misleading if its the latter...

It's not really misleading, those are the specs given at certain loads IE 273watts@8ohms and 540watts@4ohms. My amp is 150watts@8ohms and 250watts@4ohms.

The max ratings will also state distortion levels/etc. and if you read more about that you'll see whats "acceptable" to state in the manual/specifications. The power actually going to your speakers isn't always a full 273@8/540@4, that's determined by the volume level you're driving them at.

In laments terms, if the speaker being driven is a 4ohm load such as your subwoofer you purchased....your amp will see that 4ohm load and supply it the 1-540 watts (hopefully you don't turn it up that loud).

EDIT: Btw, remember to use all your t/s parameters correctly. I read about a sub or two lost due to crazy over-excursion because the way he had his box ported or sealed.....anyway just do it right. 'Nuff said.

polkanddie

Qms: 7.0, Qes: 0.62, Qts: 0.57, Vas: 0.85 cu. ft., Sd: 54.25 sq. in, Ok so what does all this mean... It needs a .85 cubic foot box sealed? I think thats all I would be doing unless I use a sonotube... btw. how would I mount the subwoofer in one of those?

kawizx9r

Maybe Ben can chime in later in regards to the sonotube. Btw, sonotubes are usually ported enclosures, the height of the sub makes up for the lack of sq. footage it occupies while still giving you a lengthy-sized port for that deep bass.

You ready to put in all the work to build this sucker? It's not hard at all, but there were some things that I had to do that I didn't like IE caulking my port tube in the inside and sealing everything,etc.

Just today I covered upsome of the nail/screw holes with some wood filler. I'll take a pic of it to show you, but just goes to show I'm not done yet. Will need to cover up the rest of the holes, sand, primer, then paint+sand+paint+sand+paint and then finish it off with a clear coat or something.

kawizx9r

Here you go, big SOB.

The lighter colored spots is where I put the wood filler in. Dreading having to take things out such as the plateamp and sub to sand things down and get it ready for paint. Who knows, it might be pushed awhile back and I'll just apply one of those laminates or something.



Maggies right next to it

polkanddie

Noice. I kinda want one to be pretty small and/or in a tube. How are you going to finish it?

kawizx9r

polkanddie wrote: »

Noice. I kinda want one to be pretty small and/or in a tube. How are you going to finish it?

Just like the guy I met told me.....cover up the holes, sand until everythings flush and smooth then primer. Sand, then paint, sand, paint, sand some more (using higher grit paper after every coat) and paint once more. By the 3rd coat or so, I'll be using 600/800 grit sand paper just to smoothen things out if necessary. Should give me a very streamlined look. I'll only do all that if time permits and if I don't just dump the whole idea altogether. I hate not having a sub when listening to music, it's the only reason why it's put together without a finish on it

polkanddie

I traded my Eosone rsf600's for this amp. It seems like a good deal since I couldnt sell them for the $150 I wanted for them... pretty sad huh.

polkanddie

I think I am going to go with a basic square sealed box with good bracing, I might up the mdf to 1" and add some carpet spikes and sometype of grill. Probably the polk one that Ive seen with this woofer..

kawizx9r

polkanddie wrote: »

I think I am going to go with a basic square sealed box with good bracing, I might up the mdf to 1" and add some carpet spikes and sometype of grill. Probably the polk one that Ive seen with this woofer..

Take it one step at a time

Always double check all your measurements, you don't want things cut out and not lining up properly if at all. 3/4" will suffice, especially for the driver you're using but if you want 1" that'll work too. I chose not to use a grill at all, nothing beats seeing my subwoofer dance like crazy with some bassy music.

Face

kawizx9r wrote: »

Just like the guy I met told me.....cover up the holes, sand until everythings flush and smooth then primer. Sand, then paint, sand, paint, sand some more (using higher grit paper after every coat) and paint once more. By the 3rd coat or so, I'll be using 600/800 grit sand paper just to smoothen things out if necessary. Should give me a very streamlined look. I'll only do all that if time permits and if I don't just dump the whole idea altogether. I hate not having a sub when listening to music, it's the only reason why it's put together without a finish on it

You're going to need 2-3 coats of primer over MDF.

ben62670

The first few coats of primer need to be light too. They are called tack coats to keep the primer from soaking too deep into the MDF.