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Topic: Subwoofer Problems - Page: 1

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Hey guys I did a birthday party Saturday night at a hall that could hold 180 people. I was using 2 EV ZLX 12P tops 250rms each and 1 EV ELX 18 sub 400rms with both L&R channels connected. I had the sub in front of my table facing the dance floor with the ZLX's on the sides of the table. My whole setup was about 5 feet away from the wall. Problem is that from my position behind the sub the bass sounded great but when I walked in front of it on the dancefloor it wasn't hitting as hard. I placed it under the table but didn't get any better results. What could be the problem not enough power or just bad sub placement. Also I only sound checked once when I first setup and the floor was empty but I did not do it again once people were dancing
 
Inviato Mon 24 Mar 14 @ 11:19 am
 
Thanks for the info
 
Maybe the output of your controller is not giving a loud enough volume to push your sub.
 
Caliente123 wrote :
Maybe the output of your controller is not giving a loud enough volume to push your sub.


I'm using a DDJ SX that should put out enough right? If not what should I look for as far as numbers? Also I was able to clip the sub but it still wasn't hitting hard
 
Does anybody have any recommendations on subs. I only want one because I'm limited on space in my vehicle
 
 
Rnow3 wrote :
Caliente123 wrote :
Maybe the output of your controller is not giving a loud enough volume to push your sub.


I'm using a DDJ SX that should put out enough right? If not what should I look for as far as numbers? Also I was able to clip the sub but it still wasn't hitting hard


Are you staging your gains properly? If not, you may be seriously degrading your sound. Do a search on the forums for proper gain staging.

Nick

PS-in terms of what sub to use, it all depends on the amount you want to spend. I haven't heard bad things about the EV you're using.
 
I would connect the Sub to the Booth Monitor Level and the speakers to The Main Out XLR. Raise the volume high on the sub and use the booth monitor level to lower or raise the bass volume.
 
Caliente123 wrote :
I would connect the Sub to the Booth Monitor Level and the speakers to The Main Out XLR. Raise the volume high on the sub and use the booth monitor level to lower or raise the bass volume.


+1 on this. First time I heard this I thought it didn't make sense, but once I did it I definitely thought it was the way to go as well.

Nick
 
Rnow3 wrote :
from my position behind the sub the bass sounded great but when I walked in front of it on the dancefloor it wasn't hitting as hard.


Maybe it just needed turning round. Some models also have a phase switch that would achieve the same thing.
 
Thanks for all the input guys, so is 400rms enough and my problem just might be placement?
 
Rnow3 wrote :
Thanks for all the input guys, so is 400rms enough and my problem just might be placement?


I'm no expert but wouldn't RMS only be a calculated concern for matching amp size to a passive speakers handling ability?
Regardless, your 700 watt sub should be enough punch using your controllers booth out.

I just tried it with a NS7 and a JBL 518S and it thumped so give that a shot.

( Thanks Caliente )
 
DJECoast wrote :
your 700 watt sub


He said it was a 400W sub. I've just had a look see, and the 400W sub is the passive model (the powered one's 700W).

I'm now wondering how Rnow3 managed to have "both L&R channels connected" to a single sub. Were you using a bridged amp?
 
Maybe I'm reading it wrong but he keeps referring to RMS, not Wattage for some reason. The ELX18 700W & ZLX12P 1000W are powered from what I'm reading.

I dont know, lets wait for him to respond.
 
The way I came up with 400 watts RMS is because the Passive version is 400 watts RMS, and I figured if the Passive version is 400 and they're both using the same speaker (EVS-18K, 457mm (18") Woofer). Then how could the Active be more powerful than the Passive and maybe they are giving more of a Peak wattage rather than an RMS wattage for the Active version. Or was I all wrong with my assumption.
 
This is not an unusual situation. Usually tho, it is not so much a case of the Sub not doing its job. But when you are behind the sound system overall you get a false impression of the sound balance. Sound becomes more directional as you progress up the frequency range. At low Bass frequencies the sound is fairly omnidirectional so you hear it everywhere. As you approach the upper mid and especially the higher top frequencies, sound becomes very directional.

The effect is that when you are standing out front and in line with your system you are hearing the full frequency range. The more off axis your ears are and especially when you move behind the speakers. The mid and top frequencies will be more attenuated. This gives a false impression of Bass lift.

There are alternate ways of positioning Sub speakers which makes a real difference to their output. As Grovin mentioned tho you do need to be aware of speaker phase. To give you an idea:

1. On the floor with the back of the cab against a wall = + 3dB lift in comparison to standing in free space.
2. On the floor in a corner = + 6dB lift. (That's a fair increase btw)
3. Against a wall but flown or mounted off the floor = - 3dB
There are many more but I am sure you get the idea. Position makes a big difference.

If you have two Sub Cabs. Place them side by side on the floor. At low frequencies they will acoustically couple and give another 3dB or so of lift in level.

Below 120hz there is no Stereo information so you can place Subs together and they do not need to be in a left/right position. Place them where you feel they sound best and don't worry :-)
Daz
 
From the description in the first post, it sounds as if the sub was further forward than the top cabs, which could also affect things (as the drivers were not physically time aligned).
 
Fair point Groovin. He also mentioned that there was little or no improvement after moving the Sub under the table which should have helped with time alignment. But as with overall phase it is well worth bearing in mind.

Daz
 
It seems like you are asking alot from a 400 watt sub.

One QSC sub is 1000 watts and most guys use 2.

You will never get 10 pounds of potatoes out of a 5 pound sack no matter how hard you try.
 
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