Suggestion for beginner build of small sealed musical sub?

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Mistertaz

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Joined 2008
#1
Hi!

I haven't tried making any speakers before, so I'm looking for a really simple but worthwhile project to start with. I've been looking on here already, but there's so many options, so I would appreciate a suggestion or two. Products seem to go in and out of production, which is another reason why I'm making a new thread.

I'm looking to make two (or more) small simple sealed subs with integrated plate amps or a separate subwoofer amp if that's a better option for multiple amps. I'm happy to go stereo or multiple mono. Would prefer actual dimensions and instructions if possible as I'm completely inexperienced with this. If there is a website with a good instructions that would be great! Should I just pick up a couple of Peerless 10" xls and build one of the recommended boxes?

Thanks!
Taz.

PS: This seems to be an oft asked question. Is it worth sticky-ing some basic Diyaudio approved projects for newbies?
 
#2
#3
He's probably going with a sealed design because he hasn't made a speaker before. A mass loaded bandpass design is pretty much the opposite direction. The sealed design is far more versatile, and should something go wrong in the calculations, the impact will be less severe.

Mistertaz, what does your current audio set up consist of, and what aspect of it do you feel is inadequate? Bass extension, bass output, uniformity across the room, etc.? All of these will determine what might be best for you.

Truly with all respect due to xrk, a bandpass design is not the way to start in subwoofers especially if you do not grasp the reason for his particular design. That is very advanced loudspeaker design for someone looking for an introduction to subwoofers. 🙂
 
#6
I'm planning to make some single driver speakers for a SET tube amp kit I'm putting together. Bass isn't exactly the strong point of SET amps or single driver speakers, so I thought building a couple of simple sealed subs for music would be a good intro before building more complex speaker cabinets.

An Eminence LAB12 in a sealed 40L enclosure sounds straight forward enough. So it doesn't matter what dimensions as long as the internal volume is 40L? What thickness ply or MDF is ideal? Does it matter whether it's forward or downward firing? Do I just stuff it loosely but full?

Sorry about all the questions.

Thanks again!
Taz.
 
#7
Hi Mistertaz,

The LAB12 sounds like good advice, as far as the volume is concerned try to keep it above 40L, even as high as 100L doesn't hurt a thing, and would give you the opportunity to add a duct at a later time to try out what it sounds like as a bass-reflex (vented) enclosure.

Regards,
 
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#8
Mistertaz said:
Hi!

I haven't tried making any speakers before, so I'm looking for a really simple but worthwhile project to start with. I've been looking on here already, but there's so many options, so I would appreciate a suggestion or two. Products seem to go in and out of production, which is another reason why I'm making a new thread.

I'm looking to make two (or more) small simple sealed subs with integrated plate amps or a separate subwoofer amp if that's a better option for multiple amps. I'm happy to go stereo or multiple mono. Would prefer actual dimensions and instructions if possible as I'm completely inexperienced with this. If there is a website with a good instructions that would be great! Should I just pick up a couple of Peerless 10" xls and build one of the recommended boxes?

Thanks!
Taz.

PS: This seems to be an oft asked question. Is it worth sticky-ing some basic Diyaudio approved projects for newbies?
Click to expand...

If you want to get into building speakers I would start with going here: LinearTeam and downloading WinISD. It is a basic modelling software for speakers.

Once you have it loaded go to "Help" then "getting started" then "entering new driver data". That will give you the information to load the driver parameters into the software.

You will need to find what are called Thiele/Small parameters for a driver you want to simulate in an enclosure.

There are many threads on diyaudio about what to do next.

The box demensions don't matter too much but large sides will need to be braced to keep them from resonating like a drumhead.

Keep asking questions, It's easier than you think. 😀
 
#9
Mistertaz said:
An Eminence LAB12 in a sealed 40L enclosure sounds straight forward enough. So it doesn't matter what dimensions as long as the internal volume is 40L? What thickness ply or MDF is ideal? Does it matter whether it's forward or downward firing? Do I just stuff it loosely but full?
Click to expand...

The dimension question has many answers but for starters just keep it a cube or similar shape.

Materials: MDF is a good starter material as it is dense and does not ring as much as plywood. (tap a piece of ply with a hammer and then tap a piece of MDF. you will hear the difference)

Forward facing is better if the crossover to the midrange is higher than 80hz. If the XO (crossover point) is 80hz or below it does not matter much.

Stuffing is a matter of taste, you will have to experiment. I would start by building your speaker (driver+box) playing it empty then stick a pillow in the box and see how that sounds.

Have fun.
 
#10
Here are the specs for the lab12 from: Eminence LAB 12 Professional 12" Subwoofer Speaker

Product Specifications for the Eminence LAB12

  • Nominal Diameter12"
  • Power Handling (RMS) 400 Watts
  • Power Handling (max) 800 Watts
  • Impedance 6 ohms
  • Frequency Response 25 to 125 Hz
  • Sensitivity 89.2 dB 1W/1m
  • Voice Coil Diameter 2.5"
  • Magnet Weight 160 oz.

Thiele-Small Parameters

  • Resonant Frequency (Fs) 22 Hz
  • DC Resistance (Re) 4.29 ohms
  • Voice Coil Inductance (Le) 1.48 mH
  • Mechanical Q (Qms) 13.32
  • Electromagnetic Q (Qes) 0.39
  • Total Q (Qts) 0.38
  • Compliance Equivalent Volume (Vas) 4.4 ft.³
  • Mechanical Compliance of Suspension (Cms) 0.35 mm/N
  • BL Product (BL) 15 Tm
  • Diaphragm Mass Inc. Airload (Mms) 146g
  • Maximum Linear Excursion (Xmax) 13 mm
  • Surface Area of Cone (Sd) 506.7 cm²
 
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#14
lemans23 said:
It always amazes me how versatile that Lab 12 is, and how in comparison, the Lab 15 doesn't seem to stack up. Perhaps it does, as I've never used it, but it doesn't seem like it can go as easily from pro, to home, to car like the 12.
Click to expand...

Once you go up to a 15 things get more specialized because they tend to like bigger boxes, which in the case of pro audio means huge. I usually don't see a benefit of going 15 over a pair of 12's in the designs I go with, mostly because i can keep a skinny form factor and lay out drivers linearly.
 
#15
In a real world application, how would a Lab 12 stack up against an Ultramax 12"?

The Ultramax has a lower frequency response and has more power, but the sensitivity is lower. I ran a quick model with both in a 2 cubic foot box and the Ultramax seems to hit about the same SPL, but 8Hz lower. I'm not sure how the Ultramax compares with clarity and clean bass though.
 
#16
You said Ultramax...
Ha ha ho ho hi hi he he 1 hr - YouTube
Dayton Audio UM12-22 12" Ultimax pdf
The UM12-22 feels better in a sealed >75L. 🙂

edit. Comparing the two, the Lab 12 has two more dB's but the UM12-22 can reproduce 4 more dB's in the low end extension, in a slightly bigger cabinet - 2.8ft³ / 80L (* Enclosure volume/F3s based on BassBox "optimum" calculations) this from specs sheet link, resulting in 2 plus more dB's@30Hz than Lab 12 (LF extension, this is).
 
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#18
kcducttaper said:
In a real world application, how would a Lab 12 stack up against an Ultramax 12"?

The Ultramax has a lower frequency response and has more power, but the sensitivity is lower. I ran a quick model with both in a 2 cubic foot box and the Ultramax seems to hit about the same SPL, but 8Hz lower. I'm not sure how the Ultramax compares with clarity and clean bass though.
Click to expand...
The Ultimax driver is designed for larger enclosures than the Lab12. If size is not a consideration, then the Ultimax is a good option.

Also: lower Fs does not equate to lower frequency response. Your enclosure will determine that more than anything. In subwoofer design, "all things considered" is a poor judge of a driver's ability. In other words, the way to determine which is the best for you is knowing the space you have available first, and then which is going to be the better choice. If a driver clearly is designed for a much lower tuning or larger enclosure, the net response may be superior with the other one. A bass box simulation won't typically tell you this. Said first driver is potentially going to have a higher system Q than the other when placed into a smaller enclosure. It would need the high compliance of a large enclosure to to decrease the effective mechanical Q. In other words: it might be fighting the box for control over the cone if the box isn't large enough. Ye don't want that in a subwoofer. 🙂
 
#19
Mdf needs to be sealed with art grade shellac or similar prior to paint to prevent moisture infiltration. It must be braced across opposing walls and brace the magnet. The pillow suggestion is a good one.

Go for the Lab12, the extra effeciency and reduced power requirements are worth a few Hz you'll never miss in music.
 
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#20
Greebster said:
Mdf needs to be sealed with art grade shellac or similar prior to paint to prevent moisture infiltration. It must be braced across opposing walls and brace the magnet. The pillow suggestion is a good one.
SNIP....
Click to expand...
I have used Zinnser BIN primer especially on box interior because it is available in spray cans. I do not overcoat it when it is on the interior.
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I recently read that Kilz oil based will seal MDF (and I have a bunch that I need to use).
Does anyone have any experience with this product?
.
Sorry for getting off subject, but OP you may want to spray the interior of the cabinet with BIN in spray cans, it works a treat and keeps moisture from slowly swelling the MDF.

Dave
 
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