# DSP vs Analogue eq?



## Bus_Boy (Dec 15, 2011)

Hoping this is the right section. 

I have 2 x Behringer FBQ3102 eq's - I bought them a long time ago for when i eventually get around to using them. I'm about to connect one up around midday today for the first time. 

Now i may be jumping the gun here wondering about alternatives without even first listening, but it's been on my mind for a while now. 

My plans for the eq's are to tame the top end and midrange honk on a set of open baffle 15'' coaxials. The other one will be used to eq an open baffle bass driver. I will use one of them also to control the crossover fq for the LLT sub.

Now i've been thinking that a DSP would "sound better" being that i'm altering the signal before it hit's the dac, rather than trying to change it after it's all ready been processed. Am i right in my thoughts, or can analouge eq's still be used in today's world where large amounts of eq can be required?


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## Gregr (Nov 2, 2010)

Bus-Man,
Don't mind me too much if I sound a little dopey. Its late and I've been falling in and out of sleep for the past 2-3 hours.

But, here we go.

Of course, you can use the analog EQ's and you will have an effect on the music. You might even find you like the effect or maybe parts of it. But anytime you add electrical circuitry to a musical signal that is already compromised because of other electrical components in the signal path, like a crossover, you've really already lost the ability to shape the signal further. This doesn't mean you cannot try, but if you like the sound it is only luck. What you've got is what it is and you can not modify the signal with any degree of predictability. 

With a digital or analog signal and digital EQ processing there are no electronic parts added to/taken away from the signal path. With a digital signal the note is simply played @ whatever db you've chosen. It is very precise and none of the adjacent frequency bands are effected and all of the laws of physics still apply. What I mean by that is some of the upper frequencies notes do reinforce lower frequencies. Depending on the instrument the upper mids and median mids add to reinforce lower notes. So you will need to be careful when adjusting upper notes, making sure they do not effect the fullness of lower notes. Vocals and dialog are effected when EQ adj hi notes be careful.

You will prefer digital EQ over analog I would almost guarantee that. 

I started writing at 6:30am today and I am not proofreading my email. Any questions..., 

As far as getting your original threads into the correct forum though. When you post your original thread you will notice at the bottom of the page there is space to include the meta language/words that could post your question, statement in more than one forum. 

Digital has its place in this analog world.


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

Analog or outboard digital EQs can certain enhance a system. However, I’d be concerned about those particular models being noisy and/or colored. I’d be interested to see what you find.

Noise will be most discernible with no input signal and the system volume turned all the way up. You might connect one channel only to the EQ and compare it to the other channel. The channel with the EQ connected should exhibit no additional noise, or perhaps only a small amount. You might have to put your ear near the speaker to hear. Just be sure and turn the volume back down immediately! 

To check for coloration, play a broadband pink noise signal through the system with the equalizer connected n and all filters set flat. If you switch the EQ in and out (i. e. bypass) there should be no change in the sound or timbre of the pink noise. If it sounds different when the EQ is switched in – that’s not good. An equalizer should not alter the sound until a filter is moved.

Regards,
Wayne


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## Bus_Boy (Dec 15, 2011)

Thanks for the replies guys. I have had a play around with the eq i have, and while i can't audibly pick any loss in transparency when i cut or boost a fq, it does seem that after i've tamed the issues with the OB it seems to take away the livelyness and some of the energy, instruments and vocals begin to appear reccessed. 

Digital must be the way to go. Which way to go about it though i'm unsure, part of the reason why i bought the analog eq in the first place was due to my lack of knowledge when it comes to all things digital. 

I guess i should run through the equipment i have, and what i want to acheive, then perhaps some reccomendations 

Currently i have - 

3 x EP2000 One for the coaxials, one for the sub, and the other spare for when i find a suitable OB bass driver to cover the 100-500hz region.

15'' Audio Nirvana coaxials

BRP into Emotiva XDA1 dac

I would like a DSP that has a digital output so i can continue to use my XDA1, as i don't run a pre-amp i use the volume function on the dac. 

I need to be able to eq both the coaxials, and the bass drivers individually, and provide a subwoofer output and crossover selection. 

Do the Behringer range of DSP's allow me to eq more than one driver per channel, or must i use more than one DSP unit?

Do the DSP's allow me to select the crossover points, or would i need to incorporate and active crossover?

All the eq's i have seen the lowest selectable fq on the low cut filters is around 2.5khz, i need to be able to set the low cut filter on the bass driver to around 500hz, and the high cut around 100hz. Should i run bass drivers higher, a lot of bass drivers have a response for e.g 45hz - 2.5khz, should i use the fulll bandwidth of the speaker rather than limiting it?

As you can probably gather this will be a big learning curve for me buying the right equipment.


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