Newbie DIY sub advice

[sleepyhead]

Hello DIY section,

I posted in the subwoofer section and KEW and BoredSysAdmin, from this post What sub to import to Japan?, suggested I ask here for a possible solution. The tl;dr of it is I live in Japan, and importing is really expensive.

I have no idea when it comes to building a DIY subwoofer enclosure, so any guidance would really be appreciated.

 

[BoredSysAdmin]

Hello DIY section,

I posted in the subwoofer section and KEW and BoredSysAdmin, from this post What sub to import to Japan?, suggested I ask here for a possible solution. The tl;dr of it is I live in Japan, and importing is really expensive.

I have no idea when it comes to building a DIY subwoofer enclosure, so any guidance would really be appreciated.

To have meaningful conversation, start by finding out which raw subwoofer drivers you can find locally.
I linked to Alpine in your other thread, but now I am not sure if they sell these locally in Japan. It's for you to find out.
Dayton Audio makes has some great value subwoofer drivers and they do have local distributor - http://www.baysidenet.jp/ Browsing their online catalog is not very efficient due to auto translation and I don't understand Japanese.

I did however find this driver:
Wavecor SW263WA03 - sells for 45k yen ($436) and some dayton sub amp plates. According to simulations it would work best in Vented box with 40 to 60 liters size.
http://www.baysidenet.tv/catalog/pdf/Wavecor/Wavecor_SW263WA01_cabinet_simulations.pdf
Passive radiators also possible, but they would add additional cost for a bit smaller sub size.

Full disclosure : Take my DIY advice with a grain of salt, as I am far from expert level on the subject.

 

[lsiberian]

I remember being in your position and unfortunately there isn't a way to put all the knowledge I've gained in 8 years in single post.

Build a subwoofer is pretty much a carpentry project. So if you have the tools, knowledge and experience in that area it's a very easy thing to do. If you don't I suggest building some shelves first. Shelves have more room for error than a subwoofer.

To build a speaker you need a panel cutting device
Option 1 Table Saw(Repeatable cuts make life much easier)
Option 2 Track Saw
Option 3 Panel Saw
Option 4 Circular Saw and straight edge.(This is really painstaking, but I've build speakers with it)

To build a speaker you need a circle cutting device

Option 1 Plunge Router and a Circle cutting jig(Only thing I've personally done.)
Option 2 Jig saw and a very steady hand

You also need glue
Option 1 PL Adhesive(More forgiving of cut issues.)
Option 2 Titebond(Very easy cleanup)
Option 3 Epoxy

You need clamps
I use corner clamps a bar clamps

I list my favorite option first, but that's my personal preference.

Other helpful things

A flush trim bit
Screws, dowels or biscuits(I don't use them myself)
Round over bit

If you get a high quality blade and bit you can probably get by just fine without a sander.

Your primary goal is to build an air leak proof box. So be sure to seal the seams after glue up.

 

[BoredSysAdmin]

The key here would to
a) Find suitable driver (and a bit easier task - an amp to power it)
b) Be nice and ask someone here like lsiberian above to model it for you (calculate using special software best box type and dimensions as well as recommended power)
c) instead of doing woodwork yourself - you could consider option to outsource it to pro carpenter but cost here may vary by a lot.

 

[lovinthehd]

A mention of the usual building materials for subs, mdf (medium density fiberboard) or baltic birch or similar void-free plywood (well as much as possible), generally 18mm (3/4") thick is good.

 

[rojo]

Amazon.co.jp has the Dayton Classic 15 driver for 19,846 JPY, or < $200 USD

Box with internal dimensions of 1' 9" x 2' 1" x 2' 4" ought to net you 8 cubic feet accounting for one 3/4" thick internal brace with typical window pane style holes cut; as well as vent and driver displacement
Vents: two 4" dia x 15.5" length should give you tuning around 21.5Hz

This ought to play 110dB from 30Hz+, have an F3 around 22Hz, and play down to 18Hz at 102dB on 100 watts of power. It'll only handle around 120 watts without reaching Xmax, so a 4-ohm stable 100-watt amp should be all you need. With two 4" vents, air velocity peaks at 16m/s around 20Hz, or a little less than mach 0.05, so there shouldn't be any audible chuffing.

It's a fairly large box, but it should put out a frightening amount of bass.

Or in the same size box with your vents 22" long for a tuning of 18.5Hz, you could use this Kicker C154 giving you an F3 of 20Hz, 16Hz at 104dB before reaching xmax, and would handle 200 watts to reach a typical max output of 112dB. Up to you whether that extra infrasonic extension and power handling is worth the additional $50. (For anyone else wishing to model this driver, see page 32 of this PDF for T/S params.)

 

[annunaki]

The first step is finding a driver/woofer that is available to you at a reasonable cost.

In addition, I would check to see what building materials are readily available there. Japan is a lot different than the US on that front.

Once those areas are sourced then we can further assist you.

 

[lsiberian]

The key here would to
a) Find suitable driver (and a bit easier task - an amp to power it)
b) Be nice and ask someone here like lsiberian above to model it for you (calculate using special software best box type and dimensions as well as recommended power)
c) instead of doing woodwork yourself - you could consider option to outsource it to pro carpenter but cost here may vary by a lot.

I can model and even give you the cut list. I actually created the modeling software I use for the purpose of my project. Your best bet is probably car audio drivers. Infinity likely has them for a reasonable price in Japan.

 

[sleepyhead]

Woah THAT is a lot of useful information and a ton of homework for me! That's great stuff. It's too bad I can only click the "like" button once.

Car audio should be simple enough to find, as there are several car shops in South Osaka. Is there anything in particular that sets them apart from the ones that RoJo and BoredSysAdmin suggested? I know that some of the beefier car audio woofers have very low impedence, like 1 or 2 ohm.

With wood, there is a like a "pro" (their version of business, not general consumer) home centre near me with a lot of different sheets of wood. Time to get my translation going to find what Japanese for the different woods suggested above!

If all of this comes to less than $1000 then I'll try DIYing this. If not, I'll probably import one from the states.

 

[rojo]

Car audio should be simple enough to find, as there are several car shops in South Osaka. Is there anything in particular that sets them apart from the ones that RoJo and BoredSysAdmin suggested? I know that some of the beefier car audio woofers have very low impedence, like 1 or 2 ohm.

Remember that different drivers all have different characteristics and require enclosures of different sizes and tuning. Oftentimes, car audio and pro audio drivers have a resonant frequency too high to be suitable for a home theater (because tuning a car sub, the corner is usually around 40Hz to take advantage of the smaller space's cabin gain; and pro audio drivers focus more on loud than on deep). What makes a suitable home theater sub driver is one with a resonant frequency (Fs) of less than 25Hz, the lower the better, and a Qts around 4 or lower for ported subs (with ported being much more efficient than sealed).

And actually, that Kicker Comp sub I linked is a car audio sub. You can tell by the craaaazzyyyy dust cap and ostentatious lettering. (I believe I'd make this one down-firing if I were you.) It just happens to have a very low Fs and reasonable Qts.

As do the Infinity 1260w and 1262w someone else mentioned, even though those are generally considered car audio as well. They will do well in a smaller 2.5-ish cubic foot enclosure, but won't move as much air or pressurize as much space as the 15's I linked on Amazon Japan.

Regarding the wood, mdf will make a ton of dust and it's very dense. Void-free birch will be easier to work with I think. And it seems like I've read one guy had good success using plywood intended for subflooring.

 

[lsiberian]

Woah THAT is a lot of useful information and a ton of homework for me! That's great stuff. It's too bad I can only click the "like" button once.

Car audio should be simple enough to find, as there are several car shops in South Osaka. Is there anything in particular that sets them apart from the ones that RoJo and BoredSysAdmin suggested? I know that some of the beefier car audio woofers have very low impedence, like 1 or 2 ohm.

With wood, there is a like a "pro" (their version of business, not general consumer) home centre near me with a lot of different sheets of wood. Time to get my translation going to find what Japanese for the different woods suggested above!

If all of this comes to less than $1000 then I'll try DIYing this. If not, I'll probably import one from the states.

Remember you need to model the drivers to see if they are suitable.

Infinity and JL Audio are your best options. I'd not venture from those brands. I suppose you could try getting a Dayton Audio driver as well. That would probably be the best option.

If you have the tools it would cost a lot less than 1k, but with tools it's gonna be close to it. The table saw is by far the biggest cost. The router would be next. While it can be a lot of fun to build a subwoofer. Most people probably would view it as a chore. In your position with no tools and no experience. I'd be getting a commercial sub. Not sure if SVS has an Asian distributor, but they would be my first choice for a commercial sub. You could try hiring out the building of the enclosure, but even still you are looking at 500 for amp and driver. So your cost of materials and construction would need to be less than 500.

IME DIY is only cheaper if you have the tools already.

 

[rojo]

Remember you need to model the drivers to see if they are suitable.

Infinity and JL Audio are your best options. I'd not venture from those brands. I suppose you could try getting a Dayton Audio driver as well. That would probably be the best option.

If you have the tools it would cost a lot less than 1k, but with tools it's gonna be close to it. The table saw is by far the biggest cost. The router would be next. While it can be a lot of fun to build a subwoofer. Most people probably would view it as a chore. In your position with no tools and no experience. I'd be getting a commercial sub. Not sure if SVS has an Asian distributor, but they would be my first choice for a commercial sub. You could try hiring out the building of the enclosure, but even still you are looking at 500 for amp and driver. So your cost of materials and construction would need to be less than 500.

IME DIY is only cheaper if you have the tools already.

I've tried modeling several JL car subs but haven't found any that are especially impressive. Which model did you have in mind?

I'm struggling to understand your reluctance to endorse the Dayton or Kicker drivers I found. Did I make a mistake in my modeling and you're seeing something undesirable that I'm missing?

I'm not too worried about his ability to find an amp. If he can't source one locally, he could always just order from China couldn't he? This one, for example, ships for ￥12,311. Or he could use a car audio amp with a PC power supply if he had to.

Edit: OP, if it helps you visualize, here's how the subs model.

• Green: Dayton Classic 15 in an 8 cu. ft. vented box tuned to 21.5Hz, 120W @ 1m
• Orange: Kicker Comp 15 in an 8 cu. ft. vented box tuned to 18.5Hz, 150W @ 1m
• Yellow: Infinity Reference 1260w in a 2.5 cu. ft. box tuned to 23.5Hz, 150W @ 1m

I did 150W on the Kicker and Infinity because that's the rating of the plate amp I found on AliExpress. I did 120W on the Dayton because that's the level it starts reaching its excursion limit around 30Hz.

I checked a few car audio sub drivers from other Japanese companies (Sony, JVC, Panasonic, Pioneer, and a few others) but haven't yet found any other worthwhile candidates offering low Fs and low Qts. I'd be interested to model some Fujitsu Ten / Eclipse sub drivers, but can't find any T/S parameters for them.

Also, for what it's worth, I modeled BoredSysAdmin's suggested driver (well, the 8-ohm version of it anyway) as well and it seems only to reach about 106dB before reaching Xmax. That's not surprising, as it's only a 10.25" driver. It does have the advantage of working very well in a much smaller 1.5 cubic foot enclosure, though. If it weren't so expensive, I'd say build a pair of those, or put two into a dual-opposed 3 cubic foot box for great justice. The 4-ohm version models as much better suited for car audio.

And by the way, I know it seems like an 8 cubic foot box is drastically larger than one that's 2 or 3 cubic feet. But remember that it only takes adding a few inches to net several more cubic feet of internal volume. Just as an illustration, 1.5' x 1.5' x 1.5' = 3.375 cubic feet; but adding an additional 6 inches to each side gets you to 8 cubic feet. That being said, an 8 cu. ft. box is heavy enough that you should consider heavy duty locking casters as feet -- especially if you use MDF.

 

[roadrune]

Isn't Alpine Japanese?

 

[rojo]

Isn't Alpine Japanese?

Maybe. They do have a Japanese presence, although I couldn't find any component subwoofer drivers on the Alpine Japan online store. I checked the U.S. models and modeled a couple of possible candidates, but didn't find anything appropriate for home theater. The Type-S 15 did OK in a sealed box, but would need heavy EQ and a stronger amp. Even then it was still 8dB weaker at 20Hz than the Kicker Comp 15 in its vented box.

 

[roadrune]

This works well with the Alpine sws15, but need a dsp, big amp and loads og space: http://www.avsforum.com/forum/155-diy-speakers-subs/1451519-lilmike-s-lilwrecker.html

 

[BoredSysAdmin]

Also, for what it's worth, I modeled BoredSysAdmin's recommended driver (well, the 8-ohm version of it anyway) as well and it seems only to reach about 106dB before reaching Xmax. That's not surprising, as it's only a 10.25" driver. It does have the advantage of working very well in a much smaller 1.5 cubic foot enclosure, though. If it weren't so expensive, I'd say build a pair of those, or put two into a dual-opposed 3 cubic foot box for great justice. The 4-ohm version models as much better suited for car audio.

I would use word suggested, not recommended and I did said that I know very little about the subject
Kicker comp sub you've found seems to be better suited for the task

 

[rojo]

I would use word suggested, not recommended and I did said that I know very little about the subject
Kicker comp sub you've found seems to be better suited for the task

Lol ok, I fixed my word choice. That was a pretty interesting find though. I mean who among any of us knows the first thing about shopping for subs in freaking Japan, either completed or components? Your Google-fu is strong regardless.

Anyway, $250 for the driver and $120 for the amp, I'd imagine even having a professional cabinet maker or other wood worker build the enclosure he'd still come in well under a grand. Wonder whether there's a Japan equivalent of a Home Depot where he could get his planks of ply cut to size? I bet his local car audio shop could cut the holes for his driver, vents, plate amp, and windows in his bracing for $100 or less. I got holes cut in my sdx12 cabinet for $20 at a car audio shop. Granted, they just used a jigsaw, but the mounted driver and amp completely hide the rough cuts.

 

[sleepyhead]

Thanks to all the input guys. I've never seen such enthusiastic responses and help on a forum before! I've been busy the past few days, so I didn't have a chance to read the posts in detail or do much research until now.

There is a home depot kind of place near where I live and they have something like a vertical table saw (?!?! I have no idea what to call it) that can cut sheets of wood to size. Making the holes will have to be done away from the home depot as I don't think they had tools for that there. They do have a drill press. I think making the box wouldn't be a huge problem whatsoever.

I spent some time googling for drivers and I'm not getting very far. There are a lot of places selling "Fostex" and "Altec Lansing", but just from the pictures, none of them look suitable. There are lots of brands on this site, http://dp00000116.shop-pro.jp/?mode=cate&cbid=698&csid=10&page=1, so I have no idea if they are suitable or reliable. Brands I've not seen mentioned before on this site (TangBand, Goldwood, Beyma)

Car audio stuff, I can find Infinity Kappa 120.9, Focal (really expensive) and Pioneer (seems not to fit the criteria of low Fs and low Qts). There is also Alpine too. These are from other individual shops, but Amazon seems to be a good place for the others suggested here (such as kicker and dayton).I found an Eminence Lab 12C on Amazon, which looks good? If I go DIY, it looks like Amazon is the easiest port of call.

 

[rojo]

Thanks to all the input guys. I've never seen such enthusiastic responses and help on a forum before! I've been busy the past few days, so I didn't have a chance to read the posts in detail or do much research until now.

There is a home depot kind of place near where I live and they have something like a vertical table saw (?!?! I have no idea what to call it) that can cut sheets of wood to size. Making the holes will have to be done away from the home depot as I don't think they had tools for that there. They do have a drill press. I think making the box wouldn't be a huge problem whatsoever.

I spent some time googling for drivers and I'm not getting very far. There are a lot of places selling "Fostex" and "Altec Lansing", but just from the pictures, none of them look suitable. There are lots of brands on this site, http://dp00000116.shop-pro.jp/?mode=cate&cbid=698&csid=10&page=1, so I have no idea if they are suitable or reliable. Brands I've not seen mentioned before on this site (TangBand, Goldwood, Beyma)

Car audio stuff, I can find Infinity Kappa 120.9, Focal (really expensive) and Pioneer (seems not to fit the criteria of low Fs and low Qts). There is also Alpine too. These are from other individual shops, but Amazon seems to be a good place for the others suggested here (such as kicker and dayton).I found an Eminence Lab 12C on Amazon, which looks good? If I go DIY, it looks like Amazon is the easiest port of call.

Very nice research! TangBand and Eminence traditionally have a positive reputation for DIY projects. I modeled a few reasonably-priced drivers from shop-pro.jp, as well as the Infinity and the Eminence Lab 12C. The pick of the litter for your finds was the Lab 12C. Here it is modeled next to the Kicker:

• Yellow: Eminence Lab 12C, 3 cu. ft. box w/ vents tuned to 23Hz, 150W, LPF@100Hz
• Green: Eminence Lab 12C, 4.1 cu. ft. box w/ vents tuned to 23Hz, 150W, LPF@100Hz
• Orange: Kicker Comp 15, 8 cu. ft. box w/ vents tuned to 18.5Hz, 150W, LPF@100Hz

You know, I haven't really found any other sources of plate amps in Japan. Have you? Or do you think you could get something like a Crown XLS-1000 or a Behringer iNuke to power your sub?

 

[BoredSysAdmin]

Behringer are there
https://www.amazon.co.jp/s/ref=nb_sb_noss_2?__mk_ja_JP=カタカナ&url=search-alias=aps&field-keywords=inuke
and there are (rebranded?) Amcron amps which is both named and looked exactly as Crown
https://www.amazon.co.jp/s/ref=nb_sb_noss?__mk_ja_JP=カタカナ&url=search-alias=aps&field-keywords=xls+drivecore&rh=i:aps,k:xls+drivecore
They are more expensive it seems than behringers.