Bayuk89 Posted December 15, 2015 Report Share Posted December 15, 2015 I have a question and it might be silly to u but to me its not because i dont know. I dont have an oscope to set my sub amp so i just use my DMM and a 60Hz test tone. I want to set my LPF and sub sonic filter but the dial only goes in range from 15-55 hz for sub sonic and 50-250 hz LPF. I have an idea where 28hz is on sub sonic and 80hz is on LPF but i though if i could use a 28hz and 80hz test tone with sub still hooked up and tune it with those tones, my though is that the the 28hz tone wont play lower than 28hz if i tune the amp untill i dont hear it anymore then move it up a notch and thats 28hz. How far off am i from this ? I just have the basic equipment no fancy stuff yet... Link to comment Share on other sites More sharing options...
sTp Posted December 15, 2015 Report Share Posted December 15, 2015 you could try to see if anyone near you has a DD-1 if not buy one then you can set it up its better than using a DMM i am still new to this so don't really know how to set it up with a DMM i just brought a DD-1 but someone on here will be able to help you. Link to comment Share on other sites More sharing options...
Jessica Posted December 15, 2015 Report Share Posted December 15, 2015 No, your filter starts at the frequency you set it at and it is a slope not a brick wall. You can use a volt meter if you know what the slope is, ie 12db ,18db,24db... and look up the formula for what the voltage will be. You could also just a dust the filter till the voltage just starts to change and then stop. Basically, play and 80hz tone, adjust lpf and stop as soon as voltage starts to drop. Same with infrasonic. Do this with no sub hooked up Or buy a cc1 Rest in peace, walled 87 accord build log 03' Corolla build with AA Mayhem inside. My super random youtube channel and terrible camera work. Wiring comparison by CaptainzPlanetz Wire and fuse guide by Guest SyKo13 Link to comment Share on other sites More sharing options...
MotorCityFats13 Posted December 15, 2015 Report Share Posted December 15, 2015 I have a question and it might be silly to u but to me its not because i dont know. I dont have an oscope to set my sub amp so i just use my DMM and a 60Hz test tone. I want to set my LPF and sub sonic filter but the dial only goes in range from 15-55 hz for sub sonic and 50-250 hz LPF. I have an idea where 28hz is on sub sonic and 80hz is on LPF but i though if i could use a 28hz and 80hz test tone with sub still hooked up and tune it with those tones, my though is that the the 28hz tone wont play lower than 28hz if i tune the amp untill i dont hear it anymore then move it up a notch and thats 28hz. How far off am i from this ? I just have the basic equipment no fancy stuff yet... why do you use a 60hz tone when tuning with the DMM on a sub amp? sounds like a perfect formula to blow shit up when you start playing 30-50hz where most bass is at Link to comment Share on other sites More sharing options...
Bayuk89 Posted December 16, 2015 Author Report Share Posted December 16, 2015 Sorry i ment 50hz sine wave test tone, i downloaded it from a JL audio website, sine wave is at 0db its not boosted or cut. I have always used a DMM to set gain do to not having an oscope. I have a 1500 watt RMS @ 1 ohm mono block and a 750 watt RMS DVC (3 OHM each) sub. To do settings i did 750 times 1.5 which equals 1125 (im setting the amp to speakers power, do to the amp being higher output than subs) then u do the square root of 1125 which equals 33.54 now i turn the HU to 75% volume with everything at 0 and play the 50hz sine wave with sub disconnected and DMM Leads in amp on A/C volts. I turn gain ip or down till i reach 33.54 volts. Now amp is set, turn volume down and hook speaker back up. This is more accurate than setting by ear, using an oscope is the best way but i dont have one yet. I will see if anyone around me has one to use. Thank you for ur help guys Link to comment Share on other sites More sharing options...
Bayuk89 Posted December 16, 2015 Author Report Share Posted December 16, 2015 Slope on my amp is 12 db Link to comment Share on other sites More sharing options...
Bayuk89 Posted December 16, 2015 Author Report Share Posted December 16, 2015 Whats the formula u were mentioning ? My amp is 12 db octave, im pretty new to the technical settings. Link to comment Share on other sites More sharing options...
Bayuk89 Posted December 16, 2015 Author Report Share Posted December 16, 2015 Just did some digging in the tool section of the forum, came across a member who bought a hand held oscope for under $70 and he said it was good and a few other members vouched for the tool as well. Guess i know what im getting this pay check. I like the idea of the DD-1 but im a visual kinda guy and this tool will show the sine wave not just a L.E.D when it clips. EXOCONTROLO on youtube used a TPI 440 scope but its over $300 which isnt in my budget. Thanks again for all your help guys -over and out- Link to comment Share on other sites More sharing options...
MotorCityFats13 Posted December 16, 2015 Report Share Posted December 16, 2015 just remember that with box rise you will not be getting the power that vac x vac / R tells you but its a better baseline than using your nose..... mmmmm voice coils..... I did this method with 2 kicker comps "150rms" each and had the voltage up to 46vac on a 40hz tone and I know those subs were not getting 1058rms @ 2ohm Link to comment Share on other sites More sharing options...
Triticum Agricolam Posted December 16, 2015 Report Share Posted December 16, 2015 Whats the formula u were mentioning ? My amp is 12 db octave, im pretty new to the technical settings. Actually, it doesn't even matter what slope the filter uses when it comes to setting your filters. The frequency a filter is set at is the frequency at which that signal is 3 db down, regardless of slope. So if you set your subsonic filter to 25 hz, for example, your output actually starts rolling off above 25 hz, and at 25 hz its 3 db down. Just how much above 25 Hz it starts rolling off depends on the slope of the filter. Setting filters with a DMM is pretty easy to do. First you want to disconnect your subs/speakers and turn your filters all the off (all the way to the lowest frequency for high pass/subsonic filters, the opposite for low pass filters). Then you play a tone at your desired filter frequency at moderately high level, measure the voltage with your DMM. Multiply that voltage times .707 (or divide it by 1.41, you get the same thing either way). Turn up your filter until your measured output voltage drops to the value you just calculated. You're done. Hook your speakers/subs back up. "Nothing prevents people from knowing the truth more than the belief they already know it.""Making bass is easy, making music is the hard part."Builds: Link to comment Share on other sites More sharing options...
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