where to place microphone for EQ calibration

[anwaypasible 10+ year member]

i understand that the best place would be where my head is since that is where my ears are.. but i cannot make adjustments to the EQ from outside of the vehicle, and i also want the passenger seat to experience the calibrated EQ.

i have a calibrated microphone and i use room EQ wizard for now (planning on purchasing trueRTA in the future for the oscilliscope/soundcard calibration functions)

i tried to calibrate the EQ once already with the microphone at ear level, directly in the middle of the two front seats.

i'm not fully pleased with the results, and when i am in the driver seat and lean in towards the center of the vehicle, i can hear subtle changes in the way the audio sounds.

my headunit has time alignment adjustments.. but the driver seat is not the only selection.

the measurements are taken FROM the driver seat.. and then you can select if you want the stereo imaging to be tweaked for the driver seat (using the measurements taken and input into the radio)

or you can select the passenger seat (simply flips the measurements around for the opposite seat)

but then there is also another setting that chooses BOTH the driver seat and the passenger seat (this is keeping the two rear speakers the same, and increasing the latency of the front two speakers so that the rear fill is on par with the front)

i usually keep the time alignment setting on the front two seats, so that there isnt any difference heard if you are in the driver seat or passenger seat.

with that said, is it better to put the mic in the middle of the front two seats or should i put the mic in the passenger seat (where the head is) and not worry about the middle airspace of the car..?

i know that in the house, you calibrate where your head is and the audio sounds very different along the walls.

and i think maybe the same effect is taking place in the car.

the reason i think this is because i cant hear the same amount of bass in the driver seat compared to when i lean my head towards the middle of the car.. specifically the 80hz area.

i have my fronts and rears setup with a 12dB/octave crossover at the 80hz frequency.

and just talking about, i think i am going to crossover the front speakers at 125hz because they are stock speakers trying to reproduce the full spectrum without an additional crossover and tweeter.

i know that the current setup is far from optimal, and i plan on purchasing replacement speakers when i have the money to start working on the upgrade procedure.

i'd like to run a set of 2-way's in the front with a crossover to kill the bass.. and then run 3-ways in the back full-range.

there will be a midrange and tweeter in the front doors.. midrange and tweeter in the rear deck.. and a woofer in each of the rear doors to blend in with the subwoofer in the trunk.

i am hoping to see the woofers in the rear door work the load of 80hz - 60hz.

or maybe 100hz - 60hz.

but i will also try to lower the subwoofer crossover point even more, for experimental reasons, and work the woofers at 80hz -40hz or 100hz - 40hz or even 100hz - 30hz / 80hz - 30hz

it will generally boil down to what is needed to get the frequency response flat on the RTA.. so if the woofers cant play low and loud, i will have to get the output from the subwoofer.

my only crossover options are 50hz - 63hz - 80hz (and full-range)

so i would have to hope that my woofers in the doors can play 50hz with the crossover turned on.. or try turning the crossover off and getting down to 40hz or 30hz

just exploring my options here with upgrading the speakers and purchasing an amp.

i'll probably have to make custom crossovers so that i can lower the top-end crossover frequency of the woofer.

normal pre-built 3-way crossovers have the crossover point at like 500hz.. and i would probably want to blend the midrange and the woofer at 100hz - 150hz

but anyway..

where is the 2nd best place to put the calibration mic?

again, if i could put the mic in the driver seat and make adjustments to the EQ from outside of the car with the wireless remote, i would simply do that.. but the remote doesnt function like that.. so i am forced to stay inside the car to make adjustments.

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[James Bang 5,000+ posts]

RTA and Spatial Averaging Usage

 

[whitedragon551 5,000+ posts]

Here are some T/A equations you can use to have a "baseline" and some other things related to crossovers and such.

 

[James Bang 5,000+ posts]

^^not a good method for t/a, imo.

 

[Kastlez_ 10+ year member]

^^not a good method for t/a, imo.

I believe that's from the alpine manual. I agree I tried this and it didn't work well at all

 

[whitedragon551 5,000+ posts]

^^not a good method for t/a, imo.

Notice how I said baseline. Of course everything is about how it sounds to your ears not some mathematical formula.

I believe that's from the alpine manual. I agree I tried this and it didn't work well at all

Worked fine for me using centimeters.

 

[anwaypasible 10+ year member]

hi..

i grew tired of waiting for a response and decided to try calibrating my EQ once again, but with the microphone in the listening position for the passenger seat.. thinking that the same thing will be heard in the driver seat.. while the center of the vehicle is ignored.

the results are MUCH better and i am now proud to show my results.

before, i was unhappy and wasnt pleased at all.

i havent sat in the passenger seat to verify that the sound is the same in both front seats.. but by judging what i heard in the driver seat, i think i have obtained the best that can be had for the speakers currently in use.

the difference was enough to make me smile.. and i dont think i will ever put the mic inbetween the two front seats ever again.

while i was messing around with the RTA.. i decided to see how low i could go without asking too much from the speakers.

turns out.. i put both the front and rear crossovers at 50hz and gained quite a bit of low end extension.

i'm rather suprised by the amount of low end obtainable without distorting the midrange.

this boils down to being happy to play music with the current set of speakers, and not have to deal with a lack of bass or punch of a drum.

it doesnt sound like i have bass blockers as it did before.. i will be that much more happier while i listen to my car stereo system prior to purchasing amps and new speakers/crossovers.

**edit**

i dont believe in spatial averaging and choose to not use the method.

if it were my house.. i would measure the middle cushion of the couch and let the people sit on each end with one ear close to perfect.

but again.. i think i have learned here that if the speakers are all equal distances away (but simply opposite) from the two listening positions.. you should be able to gather data from one position and hear identical results in the other position.

since the speakers are the same distance.. just flipped opposite when you move to the other position.

the only downside is using time alignment.. you would have to average that to the middle of the couch so that one listening position isnt getting a better soundstage than the other.

i suppose this was rather an adolescent discovery.. but i dont plan on forgetting it or taking a step backwards after learning from today.