# Graphs and response time translation would be appreciated



## BLUEBOY12 (Oct 10, 2012)

Hi there,

I'm trying to achieve as flat a frequency response as possible.
I calibrated My speaker output to 75db.
Does this mean that im trying to raise all my nulls and lower all my peaks in my graph to as close to the 75 db reference line as possible?

I also have some DIY room treatment.

Would be grateful if someone could further tell me my best approach to sorting out my mountain range and response times.

cheers all!


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## EarlK (Jan 1, 2010)

Hi,

I'll compose a fairly lengthy post for you that'll hopefully offer some guidance ( it's just I need to first find the time ) . 

In the meantime, here's a pdf file created by 2 acousticians that offers guidance for measurement interpretation ( leading to good 2-chnl sound playback ) .

:sn:


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## BLUEBOY12 (Oct 10, 2012)

thanks for the response and looking forward to the read.
going to read the ams for stereo list you sent.

much appreciated.


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## EarlK (Jan 1, 2010)

Here are some articles by a Shack member. These, I consider to be required reading for the purposes of understanding EQ ( & "best practice" in it's application ) .

*Technical Articles by Wayne A. Pflughaupt*

*House Curve: What it is, why you need it, how to do it*
 * Minimal EQ, Target Levels, Hard-Knee House Curves* 
* Is the film industry's X curve suitable for home theater? * 
* System Calibration vs. Program Compensation: Will a house curve deliver sonic bliss?* 
* Gain Structure Explained: Getting the Most from Pro Audio Equipment in Your Home Theater System* 


:sn:

ps ; More stuff to come in a day or two ( after you've finished this required reading ) :T


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## BLUEBOY12 (Oct 10, 2012)

Thank you once again for all the links, 
very informative and very interesting.
The articles, as I interpret them, relate to "Home Theatre" set ups where listening is the objective.
The graph of the "house curve" totally makes sense to me.
My space (room) is for mixing music, which is why I'm shooting for a flat response,
and my understanding of shooting for a flat response is so I don't "under" or "over" represent any frequencies....(and hopefully ,this makes for better translation when recordings are played on other systems)
What I'm finding hard to grasp is...if I am correct in thinking "flat response" is considered to be the "75db" that I've calibrated my speakers at listening position. 
I'm sure the more I read , the more I'll understand it.
One thing I did also find interesting was how the "house curve" resembled the frequency curve of many mastered CD's. (I'm sure totally unrelated!)
cheers again.


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## Phillips (Aug 12, 2011)

> View attachment 42781


Just a bit of advice the waterfall graph is only useful up to 300hz.


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## EarlK (Jan 1, 2010)

Spend some time with REW's auto-EQ module and learn it's workings .

Also, measure one speaker at a time ( at your mix position ) when creating correction filters .



> My space (room) is for mixing music, which is why I'm shooting for a flat response,
> and my understanding of shooting for a flat response is so I don't "under" or "over" represent any frequencies....(and hopefully ,this makes for better translation when recordings are played on other systems)


You've got the general idea correct ( as to why a flatter response is a requirement for mixing music products ) .

In the above pic , I would use 70db as the reference level ( for the EQ module to target ) and then limit "boost EQ" to 3-5 db .

The filters produced can be exported as a text file and those can then be used by certain external EQ programs ( one such being  *EqualizerAPO*  ( if you are running Windows 7 or 8 ) .

:sn:


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## BLUEBOY12 (Oct 10, 2012)

Hi there, 
i now have numerous questions, (sorry!)
firstly, could u explain why u would use the 70db as the target reference?
using 70db as a ref would mean (for example) having to "lower" the 85hz resonance peek in my graph.
If i used 75db as a target reference ,the 85hz resonance peak would need to be raised. 
this seems confusing to me. 

2. i also dont understand what u mean by limit "boost EQ" to 3-5 db (i seriously am a newbie!)

Equalizer APO looks great...my approach will be to firstly add more bass traps and absorbers in my room, re measure it...(the tweak and re-measure approach!) then work out how to incorporate Equalizer APO for the bass frequencies if needed.
cheers again.


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## BLUEBOY12 (Oct 10, 2012)

cheers!


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## EarlK (Jan 1, 2010)

BLUEBOY12 said:


> Hi there,
> i now have numerous questions, (sorry!)
> firstly, could u explain why u would use the 70db as the target reference?
> using 70db as a ref would mean (for example) having to "lower" the 85hz resonance peek in my graph.
> ...


- 70db ( vs 75db ) seems to be a nice half-way point ( between boosting lots of frequencies & cutting lots of other frequencies ) 

- My guess is that this pic ( capture ) is both speakers playing . If so , don't use it .
- As mentioned earlier, make some captures of individual speakers ( at your listening position ) & then use REWs Auto-EQ module to equalize the defiencies that you find .



> 2. i also dont understand what u mean by limit "boost EQ" to 3-5 db (i seriously am a newbie!)


- That's a feature found within REWs Auto-EQ menu section ( that I asked you earlier to check-out ) . I guess you didn't bother to do so. :dontknow:



> Equalizer APO looks great...my approach will be to firstly add more bass traps and absorbers in my room, re measure it...(the tweak and re-measure approach!) then work out how to incorporate Equalizer APO for the bass frequencies if needed.
> cheers again.


:sn:


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## BLUEBOY12 (Oct 10, 2012)

Hi there,
This time I bothered to read REWs auto EQ!
It almost feels like I'm learning a new language.
My understanding is, I can inverse my rooms frequency curve, to match the flat response measurement.
Then I will be able to export that info as a text file and use it by importing the measurements into EQUALIZER APO. (Am I correct so far?)
The only problem is, I will be using PRO TOOLS.
I could be wrong, but I don't believe this software can be used as a PRO TOOLS plug in.
Would you know if there is an eq program (plug in) that enables me to import the text file measurements, and is also compatible with PRO TOOLS?
Would I be right in thinking ,I could possibly use the inverse frequency curve (via an eq plug in) on the PRO TOOLS master output to record and mix?.
I do also understand this is no substitute for room treatment as this approach wont cure reverb times etc.
Appreciate your time and help
Cheers again.


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## EarlK (Jan 1, 2010)

Please read my response from within your quote . 



BLUEBOY12 said:


> Hi there,
> This time I bothered to read REWs auto EQ!
> *- Good !*
> 
> ...


:sn:


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## BLUEBOY12 (Oct 10, 2012)

See what happens when you miss those jedi mind reading classes?!
I'm running Pro Tools 9 on a PC (Windows 7 ,64 bit)
I've also come across a software plugin similar to Equalizer APO, but more suited to my needs.
Its called "apulSoft apQualizr" (http://www.apulsoft.ch/apqualizr/)
I believe I can use this on my "master bus channel" in Pro Tools (as a plug in)
and add the correction filters (in text format)
If you have a free moment, could you have a quick look at it and give me your initial thoughts about it.
I do have "Arc System 2" but I'm not happy with the results.
Over the last couple of days, I've been moving my speakers around,trying to find the best placement for them.
My room frequency curve has improved. (I'll attach a pic soon)
I have also run out of real estate for any more physical room treatment.
Finally,could you explain why and what the difference (or benefit) is, when measuring speakers individually?
(I'm struggling with the idea of 2 separate measurements)
cheers again.


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## EarlK (Jan 1, 2010)

*ApEQ ?*

I've had a demo copy of apQuilizr ( for quite some time ) . 

It would work as a standin for the Equalizer APO . See  *this thread by Dozerbeatz*  to learn how he uses apQuilizr .
- Here's one of his videos ( where he talks about using apQuilizr on the output buss of one's DAW ) ;

*http://youtu.be/Fa9qlB6LK4c*

I'm pretty sure that apQuilizr's EQ filters are not settable via an ( imported .txt ) configuration file .
- One will need to create them from within the plugin .

I don't believe it'll work with Pro Tools though ( since apQuilizr is a VST based plugin ) . 

See  *this thread over at AVID *. 


There is a VST-RTAS interpreter/wrapper available ( for $100.00 ) .



*Mono ( correction ) EQ vs Individual EQ for each Speaker ?*

Simplistically; since people listen with 2 ears / while a single mic p/u only represents a single ear at a single location ( rather than a *Binaural* capture . This is a tiny kernel of reasoning as to why I believe each speaker is best EQed individually .

I realize that Dozer does apply his correction EQ in mono ( & he likes it ) // so you might want to ask him if he's ever tried stereo correction .

Bottom line, do which one sounds best to you .

*ARC System 2 ?*

I believe that you should redouble your efforts to get Arc System 2 working properly for you ( ie; don't the publishers have a forum that you can join to solicit help from ? ) .


:sn:


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## BLUEBOY12 (Oct 10, 2012)

Thanks alot for the threads. (bought the wrapper)
What i recorded,using ARC 2, did not translate well at all to other systems.
To me,when ARC 2 is on,music (or recorded takes) sound extremely pristine.
its like its doing more than "eq balancing"
almost like some sort of harmonic saturation (hard to explain)
but it just sounds very polished.
and when played on other systems, the mix falls apart.
Ive managed to remove the long reverb tail at 40hz on the waterfall graph,
and Ive cured the dip at 3-6khz and at 60hz simply by moving things around in my room.
the other problem frequencies still exist.
Im thinking,maybe those problem frequencies around 160hz - 500hz are too much for ARC 2 to handle.
BUT!...Im going to follow your advice,redouble my efforts with arc 2 
and see if these minor adjustments make any difference.
Just been on IK MULTI MEDIAS forum ,and not 1 thread about ARC 2. A bit odd.
I'll start a thread there soon.
Your advice is challenging and always helpful.
Cheers.


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## BLUEBOY12 (Oct 10, 2012)

Just remembered!
Through REW, i have only recently come across "monitoring at the right levels"
which is a concept i had no clue about.
Ive read that 85 dB SPL is a recommended listening level.
This could possibly factor into why my mixes didn't translate well.
(i'm not prepared to say i'm a bad mixer yet!)
I'll also incorporate this approach and see if there is any difference.


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## mc_lover (Aug 25, 2012)

WOW how come Rt60 in this room is very low .0.2 at 1kHz. I have never seen RT60 so low like this.
What is room volume in M3?


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## BLUEBOY12 (Oct 10, 2012)

Hey there,
you're the 3rd person to tell me this, so now I must take notice!
My only reasoning I can think of for my rt60 being so low, is that I made my own DIY bass traps some months ago without doing proper research.
So, at the time ,I bought a whole load of rockwool (which I now believe to be the wrong kind of rockwool)
And now I guess, its sucking the life out of my room .
But, strangely enough, my room doesn't sound dead or weird...(in my opinion) 
I am not a technical guy ,so I don't really know what a good reading should be at 1kHz.
I don't understand "What is room volume in M3" either!
Could you tell me if there are any pitfalls for trying to mix in a room with these rt60 readings?
I've read a few threads, but it seems like a very subjective topic.
Any help or feedback is much appreciated
Cheers.


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