# Room correction at the source computer or at a separate equalizer?



## Horacio (Jul 17, 2010)

Hello.

I'd like to understand from those with experience when it is better to use DSP at the source and when to use an equalizer? 

My system is made of a very old laptop running Win XP, JRiver 19, files are externally stored in a HDD. The computer is the only source I use. After the laptop, thru USB into Audiophileo 2>digital coax>Metrum Octave>analog RCA>stereo tube amp>B&W 804S. Also two 12" Rythmik subs that take the signal from the pre output. I also use REW and have been working hard on sub placement and tunning with all the variables available at the Rythmik back panels. Also have some room treatments.

So I have worked a lot under the 200 Hz to make the response as flat as posible using placement, treatments, and subwoofer settings. The rest I will have to deal with thru equalization, I guess. Since my source is such an old laptop, I'm looking into building a CAPS-like server (from computeraudiophile.com). If I didn't need DSP at the computer I would build a low-power server (simpler, cheaper), and maybe add a digital equalizer downstream. But it kind of makes sense to me to process at the computer, despite the bit-perfet reproduction paradigm, with something like Audiolense or ARC 2.

Thoughts?

Thank you in advance! :T


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## weverb (Aug 15, 2008)

If you have no other external sources (i.e. cd, vinyl, etc.) I would think at the computer would be best. Fewer connections and you can easily adjust 20-20k Hz. You have to be careful which eq you use if you plan on doing anything above bass frequencies. Some units will introduce noise.

In addition, you have to look at what features you want and need. Some programs and eq's can do things like delays, crossovers, etc. You may need to do a price comparison to see which route is more within budget.

You may want to look into Dirac also. Have read some interesting things about it.

http://www.computeraudiophile.com/f...ac-has-more-sane-pricing-stereo-option-17415/
http://www.computeraudiophile.com/f...dio/listening-rooms-and-pulse-response-17633/

I have no affiliation with Dirac or any DSP programs. I use an external eq due to multiple sources.


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## seiner1 (Feb 2, 2009)

I equalize from 20 Hz to 20 kHz at source, which is my PC. 

I run Foobar2000 and use its component called Convolver, I load into it impulse filters generated by the REW software.

I also tried different VST plugins (the best among them are Voxengo Pristine Space and LiquidSonics), but Convolver in Foobar still sounds better to my ears (more transparent).


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## Kal Rubinson (Aug 3, 2006)

Horacio said:


> Hello.
> 
> I'd like to understand from those with experience when it is better to use DSP at the source and when to use an equalizer?
> 
> ...


I, too, would go with EQ in the computer although, since it is upstream of the sub crossovers, it cannot help with crossover and will EQ each speaker/sub pair as a single speaker. In addition to Audiolense and ARC2, consider Accourate and DiracLive depending on how much hand's on you like. That said, since you have REW and jRiverMC, why not develop the necessary filters in REW and use the jRiver tools (convolver, roomEQ, etc.)?


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## AudiocRaver (Jun 6, 2012)

I, too, would do the EQ in the computer. I use foobar2000 with George Yhong's VST wrapper and either the Reaper ReaEQ plugin or the rs-met EasyQ plugin, all free. Filter values can come from REW. Minimal computing power is needed and performance is excellent.

Or, as Kal suggests, use the supplied, and excellent, jRiverMC filters.

Adding more outboard hardware for filtering seems a waste, although great results can be had that way, too.

At some point you will end up running into the question of whether to use minimum phase or time-corrected filtering (I have used both satisfactorily, arguments abound on either side). Since you are starting out, one of the free approaches mentioned (no time correction) will probably suffice.


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