# ARC showing a 20db dip on my sub



## apilon (May 18, 2006)

Good evening all ,

i installed my anthem mrx300 today and calibrated with ARC. My sub is a DIY LMS-R15 with Behringer ep4000. 

AS you can see on the graph i have a 20db drop from 40 to 100 

What is the best way to cure that dip???? I do not have a lot of option to move the sub which is currently standing right beside my left front . 

Thank you for your assistance 

Alain


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## AudiocRaver (Jun 6, 2012)

The first easy thing to try is to change the phase of your sub. If you are using banana plug output on the EP2000, just flip it over (single bridged output, I assume). If not, using a balanced XLR input with the right adapter, like this, will flip the phase.


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## Wayne A. Pflughaupt (Apr 13, 2006)

Also make sure you don’t have the amp’s high pass filters engaged.

Regards, 
Wayne


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## apilon (May 18, 2006)

Wayne A. Pflughaupt said:


> Also make sure you don’t have the amp’s high pass filters engaged.
> 
> Regards,
> Wayne


Ahhhh that could be it i have the filter on with 30 hz on because i read this on QSC forum , I will turn it off and make a quick measurement 

WHAT IT IS
The low-frequency (LF) filter rolls off
signals below either 30 Hz or 50 Hz.
This improves bass performance by
limiting sub-audio cone motion,
making more power available for the
speakers' rated frequency range.
The filter settings for each channel are
controlled individually through the DIP
switch settings shown. When the filter
is turned off, a 5 Hz rolloff protects
against DC or deep sub-audio inputs.
WHEN TO USE IT (OR NOT)
As a rule, your speakers will sound
better with proper filtering. Unless
you already have filtering in a
preceding device, match the setting
to the low frequency rating of your
speakers. Vented (bass reflex,
ported, etc.) speakers are especially
sensitive to cone over-excursion at
frequencies below their rated limit.
The 50 Hz filter works well with
most compact full-range speakers,
and has a slight boost at 100 Hz for
greater fullness. The 30 Hz filter is
intended for subwoofers and large
full-range cabinets. The "off"
position should be used only for
applications such as studio playback
monitoring, where you need to know
if there are unwanted sub-audio
signals present in your mix.


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## Wayne A. Pflughaupt (Apr 13, 2006)

That info has to do with pro audio subwoofers, few of which extend below 30 Hz.

Regards, 
Wayne


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