Stuff the port tight in your existing box with old (clean) socks or something similar.
Listen. You will loose a bit of efficiency, but if you are planning on a big amp, who cares.
I would also suggest using some sort of active Bass EQ. Again, if using a big amp you will be able to get the response you want with a reasonable sized box.
Listen. You will loose a bit of efficiency, but if you are planning on a big amp, who cares.
I would also suggest using some sort of active Bass EQ. Again, if using a big amp you will be able to get the response you want with a reasonable sized box.
Back to your sealed box idea. I think I read an old article in The Absolute Sound
saying that a sealed box with FS of 30 hz and a QTS of .707 realy was flat to about 16hz after room gain kicked in.
Yes, exactly!
Stuff the port in your current box - it's going to be awfully close, or at least tunable depending on how much port stuffing you use. (You are changing the box from a ported to aperiodic.)
20 cubic feet
I did series voice coils for over 15 years and never had a problem. OTHERS would frown upon that fact.
The 20 cubic foot volume for vented is correct as mentioned earlier in the thread.
Ideally, an infinite baffle type of volume would be preferred, if you could:
1) find a closet with 40 cubic foot availble to partition, and VENT
2) you can afford another driver. (if so, study manifold mounting)
** 20 cubic foot is really not that big, if you make it a phone booth style.
*** I had a pair of 17.5 cubic foot jobs along with a happy marriage for years
and years.
Jamie,
Sounds like it could be correct, and it probably will hit the excursion limits with a lot less than full power in that large of a box.
I'd try a tapped horn like the Gjallerhorn if considering a 4 x 4 x 3 foot box.
That would give a lot more "wow".
Series voice coils are not a problem as long as the polarity is correct.
I did series voice coils for over 15 years and never had a problem. OTHERS would frown upon that fact.
The 20 cubic foot volume for vented is correct as mentioned earlier in the thread.
Ideally, an infinite baffle type of volume would be preferred, if you could:
1) find a closet with 40 cubic foot availble to partition, and VENT
2) you can afford another driver. (if so, study manifold mounting)
** 20 cubic foot is really not that big, if you make it a phone booth style.
*** I had a pair of 17.5 cubic foot jobs along with a happy marriage for years
and years.
Yeah, looks like sealed is the way to go, especially with the box size for some gain down low with portedBack to your sealed box idea. I think I read an old article in The Absolute Sound
saying that a sealed box with FS of 30 hz and a QTS of .707 realy was flat to about 16hz after room gain kicked in.
There is no "current" box. I'll have to build it (if it's sealed), or have it built for me (if it's ported or more exotic).Stuff the port in your current box - it's going to be awfully close, or at least tunable depending on how much port stuffing you use. (You are changing the box from a ported to aperiodic.)
-Jamie M.
I'm currently running a no-name 12" ported sub/box on 350rms, doesn't get as low as I'd like.
Sorry, I thought the 18" was in this box, I didn't read it well enough...
No probs, lolSorry, I thought the 18" was in this box, I didn't read it well enough...
-Jamie M.
Wow? "That +4db at 17hz has me excited..."
Don't get too excited here, this a public forum; there may be kids watching! hahahaha
Wow?
An externally hosted image should be here but it was not working when we last tested it.
That +4db at 17hz has me excited, but is that 42.5 cubic feet correct?!
-Jamie M.
toysareforboys,
Why not settle for something smaller..
b
Attachments
I received this 18" subwoofer for free:
An externally hosted image should be here but it was not working when we last tested it.An externally hosted image should be here but it was not working when we last tested it.An externally hosted image should be here but it was not working when we last tested it.
It's a dual 2 ohm car sub, so possibly not the best for HT
Specs are:
3" voicecoil
Fs : 20.5 Hz
Qes : 0.57
Qms : 5.61
Qts : 0.52
Le : 5.92 mH
Sd : 1140 cm^2
Vas : 237 L
BL : 24.79 NA
Mms : 470 g
Cms : 128 uM/N
Sens : 87.22 dB 1w/1m
Wattage: 1250w RMS
Linear x-max is around ~30mm one-way by 70% BL with a total mechanical clearance of 50mm in the motor. Should move some air
I was going to power it with an EP2000 (1300rms at 4ohms bridged) unless you think there's a more appropriate weapon.
I'm currently running a no-name 12" ported sub/box on 350rms, doesn't get as low as I'd like.
Was thinking with the 18" to tune it very low, like 20hz, mostly for LFE for movies (not much music played on this system).
Let me know what you think or if this is a waste of time. If this wasn't going to work out I was going to build a 2 x 12" Infinity 1262w ported box.
-Jamie M.
Sounds like a great project.
If you don't have an amp yet, I would suggest a behringer nu3000dsp, it will bridge well into 4 ohms and have onboard dsp. Will do about 1500w into 5 ohms.
The response curve in your 40+ cubic foot model indicates that you're using a relatively high tuning for the box volume, you could go with a lower tuning, or more realisticly, a smaller box in the 10 to 20 cubic foot range. Try running more sims while keeping an eye on excursion vs. xmax vs. power.
I would not attempt to build a tapped horn with this sub.
When it's the same vc, I don't think it's a problem.One issue no one has brought up yet, is how to handle those 2 each@
2 ohm voice coils (?)
One option is to series them for a more stable 4 ohm load, but the series thing is often frowned upon.
Independent drivers in series in the same box will have a problem, the cones tend to walk opposite when played.
jn
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
- Home
- Loudspeakers
- Subwoofers
- Got 18" for free, looking for enclosure ideas for HT?