# Advice : Do's and don't of EQ ?



## Drizt (Aug 21, 2006)

Hi All,

Apologies in advance if this has been answered before. If it has could someone be kind enough to provide a link?

What are the do's and don't regarding EQ?

I have a specific example of what I have done if that helps people to tell me what I have done wrong or how they would do it differently.

I recently bought a balanced miniDSP uni -> http://www.minidsp.com/minibox/minidsp-balanced-2x4

The unit is actually great value and its extremely flexible. Have a read about it on the website above if your interested. One good feature is it gives you control down to 10Hz. 

I have two sealed 125L Maelstom-X subs powered by a Crown K2 (conservative 800W's per sub).

Below is the before and after plots for some EQ I applied today. I was just playing around to get it all working. My main aim was to extend the frequency response in my room.










Don't worry about the difference in SPL, that just wasn't set up right for the second measurement.

Basically I used the PEQ feature to add two filters to add around 10dB of boost in the bottom end. The subs still had their 80Hz crossover enabled in my Integra DHC-9.9 (LFE channel)

I have played woofer cooker and bass I love you at near reference levels and I haven't had any problems (no clipping or warning lights on the amp). I have also played Iron man through the cave scene at about -10dB which is louder than I will ever listen at and everything seems to cope fine.

Basically wondering if this is the way to do it? How would you do it differently?

Rather than boosting the low end, would you use cutting (EQ) to bring the other frequencies more in line with the natural output at 20hz?

Thanks for any help.


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## JohnM (Apr 11, 2006)

You can use the Offset control to tweak the levels of traces so they line up better. Whether you apply boost, or apply cuts and then raise the overall level ultimately has much the same effect. The thing to be wary of is trying to go beyond the limits of the sub, sounds like you have done a thorough job on that. 

Where boost is applied it is important to keep it fairly broad, a narrow boost filter creates an artificial resonance that may improve things in one measurement position but is almost guaranteed to make things worse at others. It also helps to reduce the larger peaks (such as at about 48 Hz and 70 Hz on your plot) so that the overall overall setting is not dominated by the influence of the peaks and you get a better overall balance.


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## Drizt (Aug 21, 2006)

Thank you very much for the reply. I'm going to give it another go sometime soon. Cheers.


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## Drizt (Aug 21, 2006)

Just a quick follow up on this.

I had great success using REW to automatically set the filters for my miniDSP.

I deliberately made the combination only pull down peaks without any boosting of frequencies (just trying that theory out).










Here are the REW EQ settings:










Here is the total EQ applied by the miniDSP:



Here is the measured (from the listening position) before and after:


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

Looks good. :T How does it sound?

Regards,
Wayne


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## Drizt (Aug 21, 2006)

It sounds pretty fantastic really, very smooth and powerful 

I do love my sealed boxes  They are a great compromise between box size and performance in my opinion.


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## Drizt (Aug 21, 2006)

oh, and a by the way....

The Crown K2 has an auto on/off signal sensing circuit which is a bit of a pain in the you know what. 

After about 5 seconds of no signal going to the Crown it will go into a stand by mode. Apparently it does not come out of the standby mode quick enough for running sweeps.

I took some very near field (about the plane of the outside of the driver) with the Crown K2 in its auto standby mode and then quickly did another measurement with the Crown still powered up. You can see the difference below











This had me stumped for a while until I read about the auto sensing on/off.


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