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Thread: Who here tunes their car audio? Software for Time Alignment, EQ, Crossovers?

  1. #1
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    Who here tunes their car audio? Software for Time Alignment, EQ, Crossovers?

    I came across an interesting article: http://www.diymobileaudio.com/forum/showthread.php?t=17

    I would like to do some tuning... does anyone here have any experience with it?

    Is there any software out there does time alignment? What about good digital crossovers and equalizers?

    I'm running an Audgiy 2NX and would prefer to not buy an MAudio caard... even then I don't think that you can do time alignment with their products.

    TIA!
    '03 Intensa Blue Pearl Lexus IS300

    Specs: Xenarc 700TS, Opus 150W PSU, CarCPU Case, 2.0 GHz Celeron D, DFI PS-35-BL, SB Audigy2 NX, Centrafuse 1.4

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  2. #2
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    I have also been looking for a good crossover program. I'm running an extigy and for now I have just been using an electronic MTX crossover. Time alignment I'm not too concerned about time alignment as i just use front kicks. EQ is easy ala winamp/roadrunner or other software. Even audigy drivers should have it.

  3. #3
    Variable Bitrate SickVette's Avatar
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    I do alot of tuning. I use an Audio Control RTA though. To have the most control over your system and maximize the tune you will need to have a 1/3rd octave eq and variable xovers. The xovers can be passive or active. Often I get a base setting on the xovers and do not adjust them after that. The eq is very important. A standard eq does not allow for fine adjustements....standard meaning indash 7 band and simular.

  4. #4
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    I'm not doing this, but I'd like to. ;-)

    Given that high-quality, 8-channel sound cards are getting fairly cheap these days, it is not unreasonable to drive every speaker through a dedicated amp, without any external crossovers (passive or active) whatsoever. Even a low end machine should have plenty of power for a high-resolution EQ and time delay for each channel.

    The best part is that you can auto-tune the system on the fly depending on conditions -- number and location of passengers, windows up or down, sunroof/convertible top open/closed, etc.

    I started some Linux-based DJ software a few years back to move all the gear in my rack (EQ, compressor, active x-over, effects boxes) except the amps into the PC and this isn't all that much different.

    All I need is the time to get back to work on it...

    -p.

  5. #5
    MySQL Error scott_fx's Avatar
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    you can get time alignment as well as x-over and eq adjustments if you are using the kxdrivers with your pci sb card. or you can get an auto time alignment if you use an external dsp like the alpine one i'm using.
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  6. #6
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    everyone has their own preferences for tuning. some folks like to tune their mids first, some their tweets down. up to you.

    I prefer to start with the crossover. I set everything fullrange, and play the drivers one at a time, turning down the cutoff frequencies till it starts to sound dull. that tells me the limits of every driver. then I go with the more conservative setting and set them equal betweet each set of drivers on both sides of the car. the more overlap potential I have, the more options I have when setting the actual usable crossover point in the car.

    usually the steeper the slope, the better. But this is also subject to personal preference. shallower slopes integrate speakers together better, but in an envoronment we often separate the drivers far apart, such shallow slopes often create muddy localization and endless phase problems in the actual crossover region. most well tuned cars I sit in run the steepest slope they can get their hands on. Also its important to use the same slope between two drivers (example: tweeter highpass and midrange lowpass). using different slopes also change the rolloff characteristics between the frequency response just above versus just below the cutoff point, and it messes with tonality.

    once you've got your crossover points set, you can work with phase if you want. I personally prefer my phase all equal, but I'm no world class competitor. often times using kickpanel locations the tuner can flip the phase of the drivers side midrange, and not need any TA/stageEQ!

    from here, I tune my gains. with a zero bit track Ill turn my gains/volume as loud as I can without hearing any noise. this lets me maximize the potential volume of all drivers without any noise, ever. from here on out, my only noise problems are road noise.

    of course, usually dong this means my bass is too loud, the tweeters are poorly balenced, etc. so I grab my radioshack meter and a pink noise track and play pinknoise through each one of my stage speakers and attenuate all gains individually to my weakest speaker.

    I perform all this before I even THINK about starting to tune! By now, cymbals and other highs in center stage are usually above the steering wheel, and kickdrums in the center sound like they are far left.

    here is where tuning starts to get very, very divergent. some folks dont believe in TA. some dont believe in using a stereo EQ to tune stage location. Some believe in neither! I recommend trying all three, so you can get a feel for it.

    from now on, your two enemies are phase and tonality. if you dont believe in stageEQ-ing, you are going to use your TA if needed (not always needed) to get your drivers centered. if you have a tweeter with a very high cutoff point, you wont need to TA the driver. the time dependant nature of sound really only affects performance below 500 Hz. with a low cutoff point tweet (3000 Hz or so) some of those frequencies leak through, and you *may* have to apply some TA.

    I had a paragraph typed up, but since there are multiple theories on fine tuning (all valid) I am going ot make subsequent posts on it so everythign is a little neater.

  7. #7
    Constant Bitrate accentsound's Avatar
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    All in all as the main influence on such adjustements and tuning is Driver Placement. You pretty much have to do it when first installing the system. Even then you are limited by the loactions available to stick drivers.

    After that it is pretty much a perception issue. And that is usually different for each individual. Oh you can use scopes and RTA's and test disks until you are blue in the face.

    As many time as not what you hear can be at odds with what the instruments say. Tunig in such a manner is useful to get a system into the ball park. After that, it is sit in the car and tweak levels until it sounds good to you.

    Dynamics change in a vehicle from a ton of variables. Temp, Humidity, How many people are in the car, windows up, windows down, AC on or Off. Groceries in the back seat etc.

    While Auto TDA systems are cute toys, I feel that they are mainly expensive frills that do not live up to thier claims. Even if they did, the benefit of some thing that could only be measured by test equipment and not the human ear in a Automotive environment is for all purposes useless.

  8. #8
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    whats interesting to note is that a computer can not be used to tune perfection. the best a computer can do is equilize gain, TA, and FR for all drivers to the listener's ear.

    once the listener puts his legs in the footwell, FR changes. equilizing gain and TA puts the stage directly over the steering wheel, not over the center of the dash!

    So, some people say the computer is a junk tool for tuning. and technically, they are right. youll always have to polish your stage by ear.

    Im not willing to go that far yet. anyone here can computer tune their car using a program called "speaker workshop" and ANY microphone. since we are talking about a comparative analysis, we do not care about absolute FR, merely comparative FR.

    we can take plots like this:
    http://www.objext.com/semi/first,equalgain.jpg

    you can see the absolute FR looks HORRIBLE. its the mic. doesnt matter, we just care about the comparative FR plots from left to right side. looks terrible still!

    but we can continute to take farfield measurements till we get things a little more equal. (attenuating, NEVER boosting!)
    http://www.objext.com/semi/second,eqadjust.jpg

    we can also take time dependant measurements to get everything perfectly time aligned to the drivers ear.

    all this computer tuning, and your stage sits in front of your face, rather than even with the dashboard oops!

    its still a fun (free!) program, I recommend everyone try it.

  9. #9
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    now, the bottom line, as said before, is phase and gain.

    the key idea here for EQ tuning is the fact that gain AFFECTS phase! so we can push around instruments using an EQ!

    parametric and graphic, that TOO is personal preference. I'm a parametric EQ guy. buddy of mine is a graphic guy. both our cars have sounded great in the past.

    the idea is simple. once youve got your gains evened out, you play a sweep. in the car, itll sound like it sits directly in the center of the vehicle, where the proper stage can be. of course an untuned car, that speep is gonna move all over the place in the car. down low itll be REALLY drivers side oriented (remember, NO TA has been applied here) up high it could be anywhere.

    so as the sweep is played, the EQ is adjusted in each band to shift the sweep to center. always attenuating, never boosting. once its been centered, the sweep is played again, and focussed even more.

    using this method (and midbass WILL move around with enough gain change) you can actually tune a VERY focussed AMAZING stage without using TA at all, even using door locations!

    using the computer, you can do the same thing, but itll be far, far, far less accurate than the sweep. I'm so glad accentsound chimed in about the fallacy of computer tuning.

    But I invite everyone to read the technical papers of Dan Wiggins (president of Adire Audio) and Stephen Kephart, who are the main drive in my realm of experience behind gain/stage EQ tuning, without need for TA.

  10. #10
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    every audio feature is linked. everything. you can test this yourself with speaker workshop, as you adjust TA, or adjust gain, you affect the frequency response. period.

    I'm not so great a tuner yet that I know how to minimize sticking my hands into the signal to tune things in. as a result, I will probably never have a car that can take world finals. this doesnt mean I can't have an AMAZING sounding car.

    TA can be a very usefl tool to push around lower frequencies. When I tune my TA, I like to use a track on the usaci disc titled "wishing well" by Michael Ruff. It has a kickdrum, bass guitar, and vocal track all dead center. So I have something that have widely varying frequency ranges, all centered. This lets me TA my kickdrum and/or bass guitar to center, without overshooting the setting, or changing the gain enough. not not enough, as the case may be!

    you will end up with far less focus using this method versus the first, unless you take accentsound's advice about speaker positioning (which can have AMAZING resuts combined).

    there isnt too much to be specific about here. I'm not an expert in this method of tuning, so the best I know is that its more than simply a "balence" between TA and gain settings. what is there more? no idea! someone else can chime in, hopefully will be more specific than "TA is used to compensate for unequal pathlengths from the same drivers to the listener position". I've certainly never been told more than that! doesnt help tuning, does it....

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