# How To EQ For Better Sound Staging Without an RTA



## candaddy

Lots of folks have an EQ in their system, but fewer actually have access to an RTA or PC based RTA system, however this does not mean your sound stage has to wander all over your dash and seem incoherent! I'm going to illustrate a method I use to get my sound stage centered and sounding spectacular in less than an hour.

1) I'm not going to cover speaker placement, install, time alignment, phasing, level matching etc. These are all very important subjects but are outside the scope of what I'm presenting here. Remember that all of the above should be optimised before you go nuts with your EQ. The EQ should always be the last step in the process.

2) You must have an EQ that works on both the right and left channels separately. If you just have an in-dash deal that works on both channels at the same time, you're SOL. For the following I will be using the Autosound 2000 test CD number 103 "My Disk" which is available from Crutchfield among others.

Here's how to do it:

Start by zeroing your fader left/right balance if it's not already. I'll then set a general listening volume using the reference tracks at the beginning of the CD, this is not critical, you just want to do your evaluation at a general listening volume that is somewhat close to how you like to listen to your music. Don't blast it ridiculously loud, but don't keep it too quiet either, your results may vary depending on volume because of reflection intensity (which by the way, means you need the doors closed and windows up to simulate a true driving condition).

Once you have a volume level set, you'll want to skip ahead to tracks 47 - 56 which contain band-limited pink noise in 1/3 octave steps starting at 25hz and ending at 20khz. These are the same frequency ranges you would see on a standard 1/3 octave RTA and may correspond with your EQ frequencies (as it does on my Audiocontrol unit).

The next step will be to sit in the seat you will be EQ'ing for and listen to each track segment while noting the position of the phantom image on your sound stage for that frequency band. For instance:

Tracks 47 and 48 are interesting, but at these frequencies, positioning is phase dependent rather than volume dependent, so you won't be able to shift the focus of the phantom image with your EQ in these frequencies. If that did work for you, it's probably because the speakers are resonating (in your doors, or whatever) and causing some higher frequencies to give away their location. Either way, I skip these two tracks and head straight to track number 49 which begins at 100hz and ends at 160hz.

While listening to track 49, I'll pick a point on the windshield, dash or horizon where the sound seems to be emanating from for each of the three frequencies. The 100hz frequency should sound really centered, because again 100hz isn't very volume dependent. Then at 125hz you might notice a shift (again somewhat unlikely) however the final segment of this track at 160hz may have shifted somewhat. If so, note where it seems to be coming from, say the right side of the steering wheel. We now know that 160hz needs to shift to our left very slightly. 

I have the ability to EQ right from the driver's seat and that allows me to tune as I listen (from that location), however not everyone has that ability. If you're EQ/s are in the trunk, then you'll need to make a note on some scratch paper for making the adjustments, or have a buddy tweak it while you point left or right.

While tweaking in real time, I'll stop right there and adjust 160hz until it sounds perfectly centered to me, before moving on. If you can't do that however, just make notes as you progress from track to track. I like to cut and boost equally while doing this, so I might raise one side by +2db and lower the other by -2db. This way the difference is 4db but the sum is still 0db total cut or boost at this stage (Understand that levels might need resetting later, but again that's not part of this tutorial).

As you move your way up the frequency range you will find that it becomes increasingly easy to note differences and adjust them precisely. This is because your ears are more sensitive to volume differences the higher the frequency, rather than phase relationships as with lower frequencies. You should get a feel for how much difference between left/right you'll need for a given movement of the phantom image (total of 2db, 4db, 6db, etc.).

After going from track 49 all the way to track 56 and making your adjustments, listen to those tracks again in succession and try to see if the phantom image (focal point of the sound) shifts at all. You might note that it moves up and down at times depending on frequency and that's OK, but it should not be shifting right and left, you'd like it to always sound as though it's directly in front of you.

Once you've successfully achieved a perfectly centered image for all of the pink noise tracks, you're ready to go back to some reference music and see how your system sounds! 

If your image shifted around at all during the process outlined above prior to setting your left/right EQ, you should find that the imaging of your music has vastly improved. Left and right imaging should sound more equal (rather than nearside too close to being in front of you and far side WAY far away, for instance). Additionally, you might get a greater sense of depth and ambiance. This is the kind of EQing that will make the difference between a "pretty good" sound system and one that sounds "spectacular." 

If you choose to do further EQ work to adjust your frequency response, you need only to keep the relative left/right balance in mind for each frequency and you will always enjoy your perfect sound stage imaging.

Good luck and have fun!


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## DanMan

Thanks for taking the time to write this up.

I have tried several times to use this method. I always came away with mixed feelings about the results. I seem to have a hard time feeling confident about locating the frequency.

Maybe this is because I am using a parametric eq.(Zapco DC amp with 10 bands parametric per driver. Adjustable frequency, Q, and shelf.)

How could I best simulate a graphic eq with a parametric?


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## candaddy

I think you're possibly creating problems as you're trying to solve them with that setup. When you change the Q and the boost-cut of each frequency (as well as the frequency itself) the "skirt" can overlap another and cause phase relationships that could lead to comb filtering or other issues. I'm not at all familiar with that unit, but that is a very real possibility.

I guess I'd listen and make notes using the CD I recommended and then choose the frequencies that are the worst and deal with them mainly trying to make sure you don't overlap your adjustments. In other words, don't do a -7 right at 1000hz and a +5 right at 1.25khz because the skirts of each will overlap and possibly cause problems (even with a really narrow Q setting). 

I think you'd be better off to get a constant Q graphic EQ for this type of work and save the parametric for smoothing the overall frequency response, or at least that's what I've always used parametrics for. Maybe someone with more experience with one can comment. You might also contact Zapco and see if they can help you.


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## faiz23

what rta do you like


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## jsun_g

Thanks for the useful input. I have an alternate approach that I'd like to post as well, also using the Autosound 2000 CD (I am not sure if I am talking about the same CD as you have posted but on track 4, there is a 1 minute slow sine sweep...that is what I use). The 1/3 octave tones are IMHO a good method to get a 10,000 foot view of your response but sine sweep is also needed to see all the little peaks and troughs between. A caveat IMHO of the sine sweep is the level can gradually change several DB over say 15 seconds and it may not be easy to notice, but you sure will notice it with music, so it takes some training to recognize.

This weekend I attempted tweaking with Winmls and binaural microphones mounted in my ears but I haven't quite gotten that approach down yet, so I stick with my tried & true approach for now.

You'll also need capability of EQ'ing left and right channels separately.

For setup, make sure everything is zero'd out...balance/fader/EQ/whatever.
Also bring a computer or laptop out to your car and a good set of headphones. I first listen to the sine sweep on the trusted headphones (granted it is a much more controlled environment). I remember how it sounds to me...as the frequency increases I think of an airplane about to take off (i.e. amplitude increasing), but it doesn't happen...it is just a continuous response that is easy on the ears. Then I listen to the sweep on my stereo (front and subs on, rear fill off) and check for a gap in volume (up or down) near each crossover frequency. This can be corrected by amplifier gain or swapping phase on one of the speakers.
Once that is taken care of, I go back to the headphones for a refresher.
Then back to the car stereo, with only the left side playing. This time I am listening for that "airplane" about to take off and note the time (in seconds) where each peak occurs. The paper insert for the Autosound CD has a second-to-frequency mapping; I then make EQ adjustments and repeat until the peaks are gone. Then I go back and take care of the troughs. I take a final listen of the left side and the headphones for comparison. Once satisfied, I repeat the same process for the right side only. Finally, I run the sweep again with both left and right sides on, listening for what makes me think of a car wandering to one side of a road (when one side is louder than the other in a range of frequencies it gives this effect), as well as listening for the airplane taking off. For the left/right imbalance, I adjust EQ on one channel (left or right), and for the airplane taking off, I adjust equally on both left and right.

Once all that is done I compare again with the headphones and make any final adjustments. Finally I turn off everything except for rear fill and do a quick EQ on that to be sure that no frequencies really stand out from others & can draw focus to the back of the car.

Final step is to power up everything and adjust the fader such that the rear fill does not draw attention, then make any final adjustments with well-recorded music you are familiar with.

That's the approach I use and the reason I like it is because throughout the whole process it is all centered on how it sounds to you. No fancy microphones or software needed.


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## mennitti

Which Autosound 2000 CD are each of you using? There are several, correct?


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## jsun_g

Sorry... I was using CD101 regarding my post above.



mennitti said:


> Which Autosound 2000 CD are each of you using? There are several, correct?


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## candaddy

That's a good addition to the post. 

I don't like to eq for frequency response by ear using that sine sweep because you end up with a fletcher munson chart ("smiley face" eq settings). It will definitely help you find major problems though and certainly allow you to see if you have a left/right balance problem.


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