Post by chowterheadMy understanding is that a single channel of a QSC RMX 2450 (which is what
we use) is a good match with the Behringer B1800X subwoofer. Additionally,
we ran this using a Driverack PA. I don't believe we ever ran it where it
was clipping, seemed like we had a lot of headroom. I'm guessing (given
some members of my band's lack of respect for being delicate with equipment)
that it just got bumped/jostled too much.
Has anyone taken a good look at the specs on this box? Here they are
from the Uli site:
B1800X
Subwoofer (18")
Frequency response 40 Hz - 300 Hz (-10 dB)
Power rating(1) (RMS) 800 W
Power rating (Peak Program) 1600 W
Impedance 8 O
Sound pressure level2 (1 W @ 1 m) 100 dB (Half Space)
(1) Average value over bandwidth of 50 Hz - 5 kHz (multi-way systems)
and 40 Hz - 250 Hz (subwoofer) according to IEC 268-5.
These are awfully impressive specs for such a cheap box, with a
calculated peak SPL of ~131 dB not including power compression. I'm not
buying it. But anyhow, in theory, it should be powered with an amp that
can deliver in the neighborhood of 1600 watts into an 8 ohm load. So in
theory, a QSC RMX2450 should be fine running bridge mode into one (1500
watts continuous output EIA 1KHz into 8 ohms). I hate that they only
rate that amp on the web page at 1KHz, as most power amps don't put out
anywhere near their spec'd power at the lower end of their frequency
band into reactive loads. Regardless, it should not be too much power.
It should be noted, however, that many subs cannot take their rated
power in the lowest octave(s) of their operating range. This box has
10dB down point at 40Hz, not very good. So that means it doesn't have
any substantial output probably below 50Hz. Not much of a "sub" in my
opinion. But regardless, if you're driving this thing with out a high
pass filter say around 45-50Hz, you're asking for trouble, especially
if you have an amp good at delivering power in the low frequency band
into reactive loads and you're pushing frequencies below the tuning of
the box so the driver is unloading. This could be what killed the
driver. Or, it could simply be a mechanical defect that finally came to
fruition. For the future, I would make sure you're running a proper
high pass for it on your
DriveRack. If you've only been using one side of the RMX2450 to power
it, you're technically under-powering it on paper. At full clip, you
can exceed the RMS rating of the driver by a couple hundred watts and
cook it, but it sounds like you've avoided doing that.
In conclusion, I'll just say you shouldn't expect too much from box
like this, regardless of what the specs say. Uli might make some cool
processing stuff for the money, but the boxes have been less then
stellar IMO. Either get the box repaired, throw it away and get another
as it's super cheap as far as speakers go (re-coning some high end
drivers is not much less), or buy something better.
Rupert