Why is "beating speaker frequency response into submission" via EQ a bad thing?

[LBaudio]

Over EQ-ing is a bad thing ..... with rise of processors that allows to load house curve ant tune system to it it become even more problematic and more people do that mistake, but they do have almost ruller flat output (dont mind the sound, lol)

EQ IS NOT a band aid for poor install!!!! but just too many uses EQ to solve install related problems

[jtrosky]

First off - GREAT information - thank you all for your replies! As I'm rather new to all of this and still learning, I find threads like this very beneficial - both for me and other "noobs" that will eventually stumble upon it.

Just a few things I've noticed while tuning my system:

1. In my system, I've never ran into a frequency that doesn't respond normally to EQ. By "normally", I mean that adjusting the EQ by 1 dB (for example) causes 1dB of difference when I take the next measurement. I've never had something NOT respond to EQ? How can that be??

2. So far, I've just been EQ'ing each individual speaker to my customized target curve. Basically, I generated my target curve based on the overall EQ "shape" that works for me, with my hearing, in my vehicle, with my speakers - after lots of testing. The common curves just did not do it for me. But I place more importance on matching left/right than I do on matching the curve itself.

3. So far at least, I haven't found the need to EQ "whole sides", "speaker pairs" or "overall" responses. After EQ'ing each speaker individually and then taking measurements with "both sides" playing (both front door speakers, for example), the results are basically the same as they were for each individual door speaker (just louder), so I just didn't see the need to EQ anything after I EQ"d each speaker individually.

I'm NOT a "technical" SQ person - I just go with what sounds good to me (for example, I tried going without rear speakers and just cannot do it) - I like the effect my band-passed, reduced-level rear speakers give me, right or wrong. I also have very inexpensive Kenwood Excelon speakers and have no plans on upgrading to more expensive speakers (at this point - who knows what the future may bring). I also use stock speaker locations and am not interested in customizing speaker locations - just not interested in going that far - trying to make the best of what speakers I have and their stock locations.

Next I want to introduce some pictures to this thread... I think they may help get the point of my question across a little better. I recently decided to try EQ'ing my system manually instead of using the REW auto-EQ function - mainly to keep the number of PEQ filters to a minimum to see how I liked the results. However, as I took each measurement, I found myself using more and more PEQ filters to better match left/right really well, so I still ended up using a lot of PEQ filters to get to where i'm at now (which I'm actually very happy with - but always looking to make it even better). My wife even commented on how good my car sounds compared to hers - and she was sitting in the passenger seat of a drivers-seat tuned car! :-)

Next post will includes some pictures of what I did along the way - curious to see what you guys think about my decisions.

Again, thank you all for your input - it will be beneficial to me and other noobs in the future!!

[Jdunk54nl]

On note 3.

If you don't check speaker pairs, then you are leaving some on the table. But if you are happy with that, then it is fine. Without checking the pairs, I find that I can get about 90% of the way there. Right now I haven't had time to get that deep into my truck or my wife's car and have literally just used the Helix auto RTA on my truck (I did spend some time on crossover settings to get my electrical and acoustical crossovers to be where they need to be), and REW on my wife's car.

I would say both vehicles are about 90% there even though the helix auto rta only uses 31 band graphical eq. What I notice is that depending on the singers voice and certain instruments, the center images in both vehicles will drift some left or right. This is why you should check pairs using limited band pink noise with your ears! You also need to make sure that your mid/midrange/tweeter are lining up in the crossover as the overlapping frequencies are really the only place they will hurt/help each other . Some of this could be due to the actual volume level being more on one side, and some could be that the speakers are out of phase at that point that isn't due to volume.

You can check this with the microphone, it is harder to see with REW, especially if you can't do a sweep in REW. But if you have your left mid measured and the right measured, then you measure both together, all frequencies should be above the individual lines (I believe about 6db above as you doubled the power and doubled the speakers, someone please correct me if I am wrong). If it is only 2db above (or really anything less than 6db), you have phase issues that need to be addressed. They are close to being in phase, but they are not 100%.


Don't get me wrong. I understand the theories of all of this but am still honing my ear skills and still learning when to ignore REW results. Tuning my wife's car with only 10 bands of PEQ really helps this.

[jtrosky]

On note 3.

If you don't check speaker pairs, then you are leaving some on the table. But if you are happy with that, then it is fine. Without checking the pairs, I find that I can get about 90% of the way there. Right now I haven't had time to get that deep into my truck or my wife's car and have literally just used the Helix auto RTA on my truck (I did spend some time on crossover settings to get my electrical and acoustical crossovers to be where they need to be), and REW on my wife's car.

I would say both vehicles are about 90% there even though the helix auto rta only uses 31 band graphical eq. What I notice is that depending on the singers voice and certain instruments, the center images in both vehicles will drift some left or right. This is why you should check pairs using limited band pink noise with your ears! You also need to make sure that your mid/midrange/tweeter are lining up in the crossover as the overlapping frequencies are really the only place they will hurt/help each other . Some of this could be due to the actual volume level being more on one side, and some could be that the speakers are out of phase at that point that isn't due to volume.

You can check this with the microphone, it is harder to see with REW, especially if you can't do a sweep in REW. But if you have your left mid measured and the right measured, then you measure both together, all frequencies should be above the individual lines (I believe about 6db above as you doubled the power and doubled the speakers, someone please correct me if I am wrong). If it is only 2db above (or really anything less than 6db), you have phase issues that need to be addressed. They are close to being in phase, but they are not 100%.


Don't get me wrong. I understand the theories of all of this but am still honing my ear skills and still learning when to ignore REW results. Tuning my wife's car with only 10 bands of PEQ really helps this.

Like I said, I actually have checked speaker pairs - it's just that I didn't see the need to EQ anything "in pairs" or "whole sides" after checking them - they are basically the same as the individual measurements, only louder. There is some *slight* variations when measured in pairs, but we're talking 1 or 2dB at most - and only at a few spots - which could even just be measurement variances (even individual speaker measurements vary some from measurement to measurement). I guess it wouldn't hurt to try and fix those few issues I saw when measuring speaker pairs, but that would just cause me to use even more PEQ filters. :-)

I'll post some pictures of what I have seen and done - and why - and see what you guys think - I'm always open to learning more and trying different things - and I'm *sure* this will be beneficial to others as well.

I still haven't tried the Helix auto-EQ yet - but do want to try it at some point - although, I have a feeling it will use even more filters than I do and end up with more left/right variance than I get with my manual PEQ filters. But hey, I've been wrong before! :-)

I've only tuned with pink noise. Have never even got into sweeps and looking at phase in REW - mainly because my pink noise measurements didn't seem to indicate any major phase issues (based on speaker pair measurements looking the same as individual speaker measurements).

I am pretty confident in my active crossover settings, speaker level settings and TA setting though - I definitely have a solid base that isn't causing me to use more EQ than needed. Originally, my crossovers weren't optimal - but out discussion in that Helix DSP.3 thread helped a lot and I was able to optimize my crossover settings to reduce the amount of EQ boosts that I needed.

The only thing that I haven't done yet - and really need to get done - is deadening my doors. At this point, I'm going to wait until summer comes around to help with installation (don't want to install it while freezing cold) - I know I could heat it up while installing, etc - but would rather just wait until summer - especially since I still need to get a very minor power window issue addressed before I do it.

[Jdunk54nl]

Like I said, I actually have checked speaker pairs - it's just that I didn't see the need to EQ anything "in pairs" or "whole sides" after checking them - they are basically the same as the individual measurements, only louder.

Just because they are louder, doesn't mean you don't have issues. The two could be lining up like this which would increase the overall volume but still slightly out of phase.

[Hillbilly SQ]

Just because they are louder, doesn't mean you don't have issues. The two could be lining up like this which would increase the overall volume but still slightly out of phase.

I'm guessing this is what causes the summed response to be a little wonky compared to each side lining up when played solo? Stuff like this is what makes me bang my head against the wall when tuning

[jtrosky]

Just because they are louder, doesn't mean you don't have issues. The two could be lining up like this which would increase the overall volume but still slightly out of phase.

It's not just that it's louder - the actual response is the same as well. So I get a particular response when playing a single speaker. When i play both left/right at the same time, I get the same response, except that the response is a few dB higher in the measurement graph. If there were significant phase issues, I would expect the response to be different at the point where the phase is problematic. Right?

This will be a lot clearer when I post some pictures to illustrate what I mean....

[Holmz]

The idea of EQing each speaker, and then each side to address cross over regions makes sense.

i could imagine a case if the left hand side (LHS) tweeter had a different EQ, and particularly a different number of filters that the RHS... then there could be a phase difference between the LHS and RHS... so they would potentially sound good somewhere, and pull the stage in one band or another if the phase starts wandering off in a different range frequencies.

Maybe something like that is happening?

...
Full disclosure though, I have not noticed tonnes of audible difference between many of the different REW/Helix setups I have experimented with. Despite extensive tinkering, as blindly as can be at times, I feel sometimes the tune goes great and other times it's a complete failure. Strangely, I cannot pinpoint why that is, still learning.

You are probably not alone. Going from "sounds different" and correlating it to the tune, is easier than finding the causal reason why that tune is making it sound different.
(And I am not pretending to know)

[JCsAudio]

In post 25, I’m not understanding what the issue is if that is what is implied here. What does that slightly out of phase wave form picture represent in real world actual circumstances and in the tuning process? Is this something that is audible? Please give me an example? I feel like issues that are not really real world tuning issues are being brought up as issues leading to confusion here.


In post 28, stating that different EQ for each driver is causing phase issues from say the left tweeter to the right tweeter is not really an issue when it comes to what you hear after the tune. I’m not saying you are wrong here about phase changes but does it actually amount to an audible difference here? I’m strongly of the opinion that is does not. This is a new one for me and honestly I do not think this is even worth considering, and again will lead to confusion among those still learning the basics of tuning. These poor guys will be chasing their tales forever if they put any weight on that assumption.


I could be off here but based on my own experience it seems like these things are really not worth considering as issues when we follow a solid tuning process. We should set time alignment with a tape measure and forgot it forever after that. It’s just not worth fussing over fractions of an inch especially when you consider how much your head moves around during a drive and as Andy Wehmeyer pointed out in his blog. You set crossovers according to driver size (beaming) and capability to work within the passband that it was designed for and so that you are within the widest possible polar response of that driver (again below beaming). You use 24 db LR4 slopes to get the acoustical response to match the electrical response as closely as possible and so that drivers are in phase with each other and because 24 db LR4 crossovers are the easiest to implement. You set you HP filter for tweeters so that they are protected and 1.5 to 2 times the fs. You set the gain for the amplifier driving the subwoofer to clipping. You set the rest of the amplifier gains for mids/tweeters to your target curve using the amplifiers gain adjustment for those drivers according to what you like for bass level, which for me is a bass level 20 db above the midrange horizontal run or body of the target curve.You EQ each driver to a target curve and then EQ all left summed together while also checking for out of phase (polarity issues) drivers and then you match the right side so that it matches the left side as closely as possible so your stage is in the center. Measure everything together and make any final adjustments against your house curve and personal preferences by ear. You use real music you know well to test out your tune and also testing/tuning sounds like the one that comes with the AudioFrog UMI-1 (or similar) to verify your results and left, right, center. You make any final adjustments from left to right and with amplifier gains after EQ, if needed.

Hope this helps. Not trying to be confrontational here but I hate to see newcomers or members new to tuning with a DSP be possibly confused and steered into an endless abyss of confusion.

[Jdunk54nl]

Think about as you adjust your time alignment. Your speakers probably didn’t start completely out of phase. As you adjust time alignment, you are taking them from a lot out of phase, to slightly out of phase, to being more in phase.

This impacts the centering of the sound. If it isn't really close to being in phase, your center will shift and the sound levels (volume) will change. How much and is it noticeable depends on how much out of phase. The lower the frequency, the more noticeable it would be.