need some help with diy subwoofer (1 Viewer)

[betusik]

i am putting together my first ht setup and after reading through this forum i am pretty excited about building subwoofer threads and want to attemp to build one myself. i am pretty skilled but have no idea as where to start. i would want something simple for the beginning yet good sounding. i was planing to spend $300 +/- for subwoofer and same would go for material for diy sub. if someone could help me as to where to start, how to pick driver, weather to go with sealed vs ported and enclosure design i would appreciate. the thing is i dont know what to look for when selecting driver or amplifier except the price tag. it would be used in my living room that is about 14x14x10 but is directly open to kitchen and dining that is about 20x15x10. mostly for movies, plus some music and gaming. is it even worth it to build for such money? i mean for $300, will i get somewhat better sub building it?

thanks

 

[betusik]

anyone? for the beginning i would need suggestion for driver and matching amp. cant decide if 10 or 12 inch. i guess my wife would like the sub to be as small as possible so probably 10" but if icould get 12" driver enclosure somewhat small it would work. thanks

 

[John_Bilbrey]

You will certainly get more bang for your buck with a diy. That being said, I've always been a fan of bigger subs, so I would vote for a 12" - the difference in box volume isn't going to be that big of a deal - generally a few inches in each of LxWxH. I'm getting ready to start a diy 15" with stuff from parts-express.com Check them out - they have drivers, amps, even complete cabinets. They also have some nice builds on their site to steer you in the right direction.

 

[Jason Charlton]

While I don't have any direct experience building speakers, I've read the forum enough to know that if this is your first time, you should research and choose a proven design rather than start by "picking" drivers.


In terms of sealed vs. ported, if you're looking for a smaller enclosure you'll probably want to stick with a sealed design - you'll get better performance with a smaller footprint if you go sealed.

 

[betusik]

i actually like this project http://diyaudioprojects.com/Speakers/MAW-10/MAW-10.htm considering the enclosure size, i could go even little bit bigger in order to acommodate 12" driver. what do you guys think of this build? it is way below my budget by the brakdown at the end, so i might get different parts. from reading various posts it seems that i might go sealed as it is easier and enclosures are smaller. some people seem to just pick driver and than build enclosure based on recommended volume for that driver. so it looks like the driver is the first thing i need to decide for. as i mentioned before i have no idea how, so here are ones from parts express i picked just by looking at price tag.

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=293-650

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=295-404

possibly this one too

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=264-897

depending on how much i will need to spend on remaining parts

 

[brankulo]

so i narrowed it down to these two

used winISD to get enclosure size. i was leaning towards hf driver after reading reviews on PE site, but for some reason i am getting way bigger suggested enclosure size than for titanic. am i doing this right? in reviews for hf several people are mentioning they have it in 1.5cf enclosures.


also both enclosures seem to be rather tall and skinny? am i good to change dimensions to get more proportional shape?


i calculated for sealed enclosure

 

[Robert_J]

What's the Qtc on each of the designs? I like the sound of a low Q sub. You want it .707 or lower.


Yes, you can make it any shape you want without any change to the sound. The enclosure volume is what you want.


What amp are you planning on using?


If you go with the TC Sounds driver you listed earlier, it will be a step up in output and quality. I have 3 of those drivers (sold under the Stryke Audio name) and they are awesome.

 

[betusik]

i dont see qtc listed in specs.

i will try what size enclosure i will get for tc driver. what does dual voice coil mean?

planing to probably use bash 300 to stay within budget

 

[betusik]

trying to figure out enclosure size for tc driver but cant find 3 numbers in tc spec. see image

 

[Robert_J]

Le is the average of Ls and Lp.


Xmax is 18.1 mm


Sd is the surface area of the piston (cone). You can figure it out from the diameter or just use the Sd for any equivalent driver like the 12" Titanic.

 

[Robert_J]

Qtc - http://www.carstereo.com/help/Articles.cfm?id=29 Notice how the peak gets higher as the Qtc gets higher. I like a final Qtc of .5 myself.


dual voice coil - There are 2 sets of terminals to allow flexible wiring options. You want to wire the voice coils in series for a 4 ohm nominal load on the sub amp.

 

[Robert_J]

Now that I think about it a little, the Dayton is a better fit with the BASH 300. The TC is a great sub but you aren't going to let it reach its potential with a smaller amp. I've used my TC Sounds TC2+ drivers with amps closer to 500w.

 

[betusik]

with bash 300 and tc, what would i be missing comparing to 500w amp? i am not going to play it really loud at all if that matters. just want nice decent sound.

 

[Robert_J]

You would miss about 2db of maximum output. Both are excellent drivers but the TC has more potential if powered with a larger amp.

 

[betusik]

robert,

how would these 2db affect me. i dont really understand these technical stuff so if you could explain. i did some more playing in winisd with tc and titanic. could you take a look at it and tell me what you think? max volume i want to g owith is 3cf. i did sealed and vented for both drivers. vented have both 4" diam vent, 16" long. also attached graph which i dont really undrestand. thanks again. also note that i am probably not so picky about subs as you, as this will be my first one.

 

[betusik]

i can also tune both drivers down to 20hz with same 3cf enclosure with three 1.75 diam vents 15" long for tc driver
or two 2"diam vents 12" long. the thing is i can not find any port tubes that long. am i good to use pvc pipe from home depot without flared ends? is2" too small diameter for such volume?


also, do vents need to be straight? or can i run it to the back wall and than turn up for longer run?

 

[Robert_J]

If you never turn up your sub to the max, then it has no effect at all. Like the difference between a Corvette and a Ferrari. Both are great sports cars but the Ferrari will do 200+ mph while the Corvette is slightly less. When the speed limit is 70, maximum has no impact to you. Unless you have a place where you can take your sub to the absolute limits, then the TC Sounds driver is no benefit at all.


I wouldn't put either of these in such a small, ported box. It's like buying a Ferrari and only driving it to the grocery store. For a ported enclosure, I wouldn't go smaller than 4 cf tuned to 20hz with dual 3", flared ports. By the time you account for ports and braces, it will be a very large enclosure. If you want to go that route, I can find the exact plans for you.


As you found out, to tune a small enclosure lower, the port gets to be very long. When you start going with smaller ports to shorten them, then you get what we call chuffing. That's when the air speed in the port gets too fast and literally makes a "chuff" noise. We can twist and turn it but long ports also have resonance issues.


Go sealed for your first DIY sub. MDF is cheap so you can do a ported on your next box. Both subs have a very nice roll-off in your designs. Either will be an awesome sub.

 

[betusik]

i have bben playing with different enclosures all day today and i also more and more think, sealed is better way to go and also easier for first diy project. i will never have chance to play it to its full power without my wife killing me on spot. so after your explanation i will eliminate tc driver. do you have recommendation which one of remaining two to select?

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=295-464

or

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=295-404

first one has little better reviews than titanic. not sure which one to pick.


one more thing i wanted to ask is weather or not drivers come with mounting screws.


if i pair it with bash 300 is that all i need in order to work. i have read something about i need to see if it has built in high pass filter or subsonic filter. again, i have no idea and i dont know what these things do?

thanks

 

[Robert_J]

Go with the Reference 12" sub. It's sound quality oriented. The Titanic is a bruiser. Plus it has a higher inductance that you will have to deal with. As a beginner, you don't want to have to add any extra steps that can cause a project to fail.


Drivers don't come with mounting screws. PE has many different mounting options.


All of PE's plate amps have a subsonic filter. They aren't required for most sealed subs but it doesn't hurt.

 

[betusik]

all right, thanks for all your help. i will try to post images when i start the project. bash 300 is on back order till february.