Hallo there!
This will be my first post. I have searched the boards and read a lot, but I would still like your advise.
I am looking into building 2 x Eminence lab 15's in sealed enclosures for my HT, replacing my MK sound mx250's.
I arrived at the lab 15's with the limited knowlege, so none of this is set in stone. My cousin have built 2 x Ultimax 15's and they are awesome, but a tad too soft for my taste. I like a punchy and fast bass, I prefer 30hz+ over the ultra deep..
My room is 1.100 cubic feet, so I am thinking sealed since I don't need the extra SPL..
Any advise is welcome. Thanks in advance.
This will be my first post. I have searched the boards and read a lot, but I would still like your advise.
I am looking into building 2 x Eminence lab 15's in sealed enclosures for my HT, replacing my MK sound mx250's.
I arrived at the lab 15's with the limited knowlege, so none of this is set in stone. My cousin have built 2 x Ultimax 15's and they are awesome, but a tad too soft for my taste. I like a punchy and fast bass, I prefer 30hz+ over the ultra deep..
My room is 1.100 cubic feet, so I am thinking sealed since I don't need the extra SPL..
Any advise is welcome. Thanks in advance.
Nigel, you would be surprised how many good designs use Eminence drivers.
Here is an example: CS30 | Danley Sounds Labs | Danley Sound Labs, Inc.
I used lots of Fane drivers when I lived in England - I like them too, so no bias towards any of these two.
Cheers!
Anyway.. I was looking at box options - the ones on the Eminence website.. And the one that comes closest to what I was aiming for in terms of performance is their big ported box, but the ******* thing is close to 300 litres! And the biggest sealed they suggest is 108 litre with an f3 at 65 hz, though they say it can be EQ'ed much lower, no idea how much.
Anyone care to educate me?
Anyone care to educate me?
Show me a Fane driver that has a 15" cone and 12mm Xmax.
I'd love to see some data to back up your claim, though.
Since you'd have EQ available with the DSP amp, you could use a fairly small sealed box and still get decent output down low, assuming thermal power handling isn't an issue.
Hey Chris
Thank you very much for your input! I think I am making some progress.. Let's see if I got this right.. Thermal Power Handling is what the driver can take before burning up?
I got a dedicated room, and the subs will be placed in a bafflewall, so size (well 300 litre is) is not really a concern, I just have to get it through the door! According to Winsid changing box size 108 > 150 litre hardly makes a difference.. Can I trust this?
Lastly.. Would you guys make it ported or sealed? Again the room is 1100 cu ft - fairly small.
Thank you very much for your input! I think I am making some progress.. Let's see if I got this right.. Thermal Power Handling is what the driver can take before burning up?
I got a dedicated room, and the subs will be placed in a bafflewall, so size (well 300 litre is) is not really a concern, I just have to get it through the door! According to Winsid changing box size 108 > 150 litre hardly makes a difference.. Can I trust this?
Lastly.. Would you guys make it ported or sealed? Again the room is 1100 cu ft - fairly small.
Yeah, thermal is before the driver melts/catches fire.
Mechanical power handling is how much you can put in before the suspension locks up or the coil slams into the backplate (the latter can be fatal).
Thermal power handling is fairly fixed, with one problem: drivers are usually tested in free-air, which means the magnet has lots of ventilation, and the cone has lots of movement (pumps fresh air into the motor structure). If your cabinet restricts cone movement, you must derate your drivers accordingly - a ported box almost completely stops cone motion at one frequency, so the driver won't stand much power there at all. Most of the time, its not a problem, but in the PA world where you're running everything to the ragged edge, a high-power bass signal held at the right frequency will annihilate subwoofer drivers, as the coils can't vent because of the near-zero cone movement.
A tiny sealed box restricts cone motion right across the range, so it can often be difficult to hit a driver's mechanical rating, as the coil heats up too much first. The optimum, IMHO, is to play in WinISD (which is pretty accurate, FWIW) to find a sealed box where you run out of Xmax just as you're hitting the thermal ratings. A smaller box would leave some excursion unused (losing output), and a bigger box would mean you can use less power (a good thing, generally), but you've got a bigger box to put in your room.
The saving grace for thermal power handling is that movies and music are often very peaky in the low-frequency section, so there's very little constant power. Some genres of music have sustained bass notes that come in almost like sine waves - you've gotta be careful here. Stuff like this:
https://www.youtube.com/watch?v=tGDtfTZjZ7w
https://www.youtube.com/watch?v=UnQY3swM4tA
IMO, sealed boxes for where space is a concern, ported boxes where you want it louder. For your room, I'd probably go sealed. You can get more extension than ported designs by EQing carefully, and shear output shouldn't be an issue.
Chris
Mechanical power handling is how much you can put in before the suspension locks up or the coil slams into the backplate (the latter can be fatal).
Thermal power handling is fairly fixed, with one problem: drivers are usually tested in free-air, which means the magnet has lots of ventilation, and the cone has lots of movement (pumps fresh air into the motor structure). If your cabinet restricts cone movement, you must derate your drivers accordingly - a ported box almost completely stops cone motion at one frequency, so the driver won't stand much power there at all. Most of the time, its not a problem, but in the PA world where you're running everything to the ragged edge, a high-power bass signal held at the right frequency will annihilate subwoofer drivers, as the coils can't vent because of the near-zero cone movement.
A tiny sealed box restricts cone motion right across the range, so it can often be difficult to hit a driver's mechanical rating, as the coil heats up too much first. The optimum, IMHO, is to play in WinISD (which is pretty accurate, FWIW) to find a sealed box where you run out of Xmax just as you're hitting the thermal ratings. A smaller box would leave some excursion unused (losing output), and a bigger box would mean you can use less power (a good thing, generally), but you've got a bigger box to put in your room.
The saving grace for thermal power handling is that movies and music are often very peaky in the low-frequency section, so there's very little constant power. Some genres of music have sustained bass notes that come in almost like sine waves - you've gotta be careful here. Stuff like this:
https://www.youtube.com/watch?v=tGDtfTZjZ7w
https://www.youtube.com/watch?v=UnQY3swM4tA
IMO, sealed boxes for where space is a concern, ported boxes where you want it louder. For your room, I'd probably go sealed. You can get more extension than ported designs by EQing carefully, and shear output shouldn't be an issue.
Chris
Please have a look at these links:
ported subwoofer flat pack DIY Sound Group
Eminence Lab 15 kit DIY Sound Group
Ported Subwoofer Flat Pack Assembly
This is my current project using the Lab-15.
I hope it helps.
Cheers!
It's called an extended bass shelf [EBS] alignment to get the driver to go well below its Fs and take advantage of room gain to 'pump up' the deep bass.
Again, if corners are an option, then sealed is the way to go as there should be enough gain to keep thermal power distortion acceptable; otherwise do large ported tuned to ~20 Hz and use a hi-pass to protect them.
Probably best overall would be three ~0.577 Qtc sealed subs individually EQ'd..
GM
Thanks for the links dudaindc, very inspiring! That flat pack looks awesome. I aiming to do the woodcutting myself though.. Would you mind drawing me up the exact blueprints? jk hehehe ..
Thank you very much for taking your time to write that Chris, it was extremely informative, it was everything I wanted to know and more! It is pretty much a lock for me now, I'm gonna go with a sealed sub, about 130 litres, starting the build early next month.. If I want "more" bottom I can always build ported boxes later on..
You say "EQ'ing carefully" ... Well this is the last part I am rather nervous about.. Im thinking.. Can I do a full range sweep - u know REW - without a HPF and not blowing myself up? And how do I tell if it needs a HPF? My cousin turned off his HPF on his sealed Ultimax 15" and gained a lot more bottom... Im talking out my ***.. What I hear the most is that sealed cabs do not need it.. Agree?
Thanks again GM, your input is more than welcome.
Thank you very much for taking your time to write that Chris, it was extremely informative, it was everything I wanted to know and more! It is pretty much a lock for me now, I'm gonna go with a sealed sub, about 130 litres, starting the build early next month.. If I want "more" bottom I can always build ported boxes later on..
You say "EQ'ing carefully" ... Well this is the last part I am rather nervous about.. Im thinking.. Can I do a full range sweep - u know REW - without a HPF and not blowing myself up? And how do I tell if it needs a HPF? My cousin turned off his HPF on his sealed Ultimax 15" and gained a lot more bottom... Im talking out my ***..
What I hear the most is that sealed cabs do not need it.. Agree?Thanks again GM, your input is more than welcome.
Watch your power inputs, and you'll be fine. Xlim is way above Xmax, so it'll start sounding bad before you damage your drivers. Sealed boxes provide acoustic loading (resistance to cone motion) all the way down to 0Hz, so you'll be fine to run a sweep as low as you like.
It can be useful to add a high-pass filter right at the bottom end, as you might not want to reproduce some of the really really low stuff (say, 5Hz). Using a highpass would mean that you're not wasting power/excursion trying to reproduce frequencies your system simply won't do at any volume.
It sounds like your cousin had set his high-pass filter too high up, so it was taking out some of the useful range of his subwoofers.
For a system like this, I'd say somewhere in the teens of Hz is viable, depending on how loud you want it.
For more headroom, put the filter up to, say 20-25Hz. If you want to wobble everything and are happy to throw power around, 12Hz. Just remember you won't be able to run as loud.
You can avoid the compromise altogether by using dynamic EQ - that changes how much boost is being used according to how loud you're running it.
Want party levels? - your -3dB point is 35Hz
Want quieter HT? - now its 18Hz.
It works on a sliding scale, and can be really useful if done well. I don't have much experience with it myself, though. I can tell you that pretty well every sealed HT sub has it built-in, though for those its usually needed because they're trying to squeeze every last bit out of an 8" cone.
You've got plenty more speaker available, so you should be able to EQ it flat to a low cutoff and call it good.
HTH
Chris
It can be useful to add a high-pass filter right at the bottom end, as you might not want to reproduce some of the really really low stuff (say, 5Hz). Using a highpass would mean that you're not wasting power/excursion trying to reproduce frequencies your system simply won't do at any volume.
It sounds like your cousin had set his high-pass filter too high up, so it was taking out some of the useful range of his subwoofers.
For a system like this, I'd say somewhere in the teens of Hz is viable, depending on how loud you want it.
For more headroom, put the filter up to, say 20-25Hz. If you want to wobble everything and are happy to throw power around, 12Hz. Just remember you won't be able to run as loud.
You can avoid the compromise altogether by using dynamic EQ - that changes how much boost is being used according to how loud you're running it.
Want party levels? - your -3dB point is 35Hz
Want quieter HT? - now its 18Hz.
It works on a sliding scale, and can be really useful if done well. I don't have much experience with it myself, though. I can tell you that pretty well every sealed HT sub has it built-in, though for those its usually needed because they're trying to squeeze every last bit out of an 8" cone.
You've got plenty more speaker available, so you should be able to EQ it flat to a low cutoff and call it good.
HTH
Chris
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