audio control ep center mod

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there is a line of resistors that could be replace to change the frequency
does any body no what value i should use to drop it down to 10hz


Why do you want to do this thing ? There are ton's of reasons why you shouldn't, so this is why i ask...:D

If you check with Audio Control the maker of the EPI, I think you will find they have a built in SUBSONIC filter which will render your activities pretty much mute and useless by filter cancellation of anything in this range of frequency's.. So unless you undo their protective Subsonic filter that is built in, I think you might just be wasting your time trying to do this mod.... Just thinking out loud here and not picking on you or anything...:)
i am talking about the frequency chips, they put in side the are made up of just resistors the lowest audio control have is about 20hz the 35hz is made up of 22oK resistors so with highe rvalue resistors the frequency will get lower i just want the exact value

7200 divided by the frequency you have in mind = the resistance in Kilo-ohms

here is the link:
Mobile Audio Support

and this manual has their math in the bottom of the page second row of lit:

And here it is again on page 20 of this manual:
10hz is not a frequency human ears can percieve, at that level is an inaudible air pressure wave... basically you are "feeling" the bass. Its nice to have every now and then but using an epicenter with music that already sounds good can muddy the lower frequencies. Which artists do you listen to that need artificially created audio information that low?
10Hz you say, I could say you don't have that many speakers and amps to produce any good pressure at 10 or 16Hz, and your box tuning is probabaly 20Hz higher... all in all, anything below 25Hz is just car flex and wind not music

you can call it wind but that is just how some people like it with the 16hz i have when u close you can not fill the base but if u a lil distance away everything is shaking if it is not 10 or 16hz then audiocontrol maths is wroung
its not that the AC "maths is wrong" its that the wave length of a 10 or even 16hz note it what 4-5-6 times the length of the interior of your vehicle, I used to have a website/length calculator for various frequencies. But the point is, even if the modified chip will LET 10-16hz play, craziness in my book. Unless the enclosure the sub woofers are in is tuned to a frequency to allow them to play its waste.

There is a very well known enclosure building theory called the 1/4 wave theory. Get 1/4 of the fundamental tuning note you want in the car. So if that means facing the enclosure rear ward, up ward, folded horn, transmission line, whatever design, that's what you build for.

Just because the signal "says" its there, doesnt mean your system will play it.

even if u do not like , bass/electronic music. for this thread and any thread where someone says somthing about about how u cannot hear below a certain frequency, so waste of time or whatever they want to argue. listen to some dub or bass music that drops very low(preferably with 15 or bigger subwoofer, some 12s to , in a car). listen to it on an( decent ) amplifier that has a 20hz defeatable subsonic filter..

first listen to the music with the subsonic filter off.
find the lowest bass dropping music u can. listen to it for a while and get used to how it sounds so u can hear differences if changed anything, but dont change anything just hear it...

now cut all power to system . then turn the subsonic filter on.
now turn system back on to selected ( same volume ) and same songs and just listen.....

if u do this as i wrote to, u WILL defenetly hear a big difference in how the music sounds on same settings and same amp . just sub filter on or off. i can hear a huge, ill say it again,, a HUGE difference, whats wrong with youyr ears.. i have been installing 12v everything and listening to the loudest(cleanest) bass i could for the last 25 years and . im not going to post anything else after this. i wont argue with anybody about what humans can and cant hear ..
i can hear that it is not being played and it changes the sound of what i can hear being played, in a bad way... i know that what i say is from personal experience and correct. so . try it or not. but quit telling people they are waisting their time trying to hear that low bass that u think is un noticable when below the frequency of human hearing . the bass is there ,even when not audible. and when its gone . i am mad my music DOES NOT sound the same with fiter on. and if i cannot turn off subsonic filter i wont buy it .

i remember when most amps did not have subsonic filters , and when the companies started putting them into alot of amps i started to dislike subsonic filter right away. i have always loved bass and have made test cds so i know difference in music and strictly bass sine waves. . i KNOW bass . and when i read this posts topic, i started reading right away becouse i know what he is trying to do and want to know anything i can, about disabling subsonic filters.
but just as with most topics like this ,i see more people disputing the fact of hearing certain hz and arguing over if u can hear or that ur wasting time, way way more than people trying to figure out what hes doing and help him do it. i understand that some are trying to help by stating their knowledge of what will happen (possiby) and to let him know of consequences of removing/disable circuit...... but some of us know the consequinces and still want to attempt. so ... if u dont want to help , please dont say waste of time and waste this internet space.

if u want to help , state what could happen if its done, but maybe , just maybe, share ur knowledge of how to do , for the people who dont mind the (possible) consequences and want to do it... isnt this diy... do it myself, deal with it , also myself. so please help people do what THEY WANT TO DO instead of saying what we cant hear. this is my first time saying somthing about it , after years of reading people reply with WASTE OF TIME , or U CANT EVEN HEAR THAT. pff.
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