ncc74656

ordered sept 3, will arrive tomorrow.

I wanted to start large and cut my way down to small. just that my sub caught fire before I could finish

8 cubic

see, and i thought winisd was the program to use for modeling how a speaker will behave. i think one of the reasons im flying all over the place is i do not seem to be able to find any concrete rules for speaker design and enclosure building that everyone agrees on. i will buy the book on amazon if they have an ebook

my primary goal in all this is to learn the ins and outs of car audio. secondary goal is to build a good system. does anyone know where i can find a copy of the loud speaker cook book? you mention i should factor in less power, the nominal impedance according to winisd would be about 7ohm so should i assume the sub will be getting 800 ish watts for the computation of air flow?

yes, when i built my current box i pulled up the cut sheets that FI has on here and used the same port area. i also kept it around the same cubic footage +/- .2. ok so here is what im not quite following: the specs on the sub are input into winisd and that will tell me how the sub will handle power and how it will reproduce sound. so it tells me the air speed at the port, tells me the rough frequency curve not factoring in cab gain, and how much power the amp is using. so from that information i design a box to the proper size specs. now the box that Fi has on there cut sheets and the basic math i do shows about the same port area, but when i use the programs online it gives me a min port area of 3X that amount. now my air speed is about 20f/s so thats WAY below what people say to max at so perhaps i have to much port area? secondly if i build my box factoring in cabin gain and using winisd and ignoring factory specs would my box not be better than the factory boxes? finially: I am not certain i fully understand how cubic volume effects things. when i had a box build years ago i was told that it would be great with high range 40hz area, but if i wanted it to reproduce lower range i would need to build it bigger so it had more cubic footage to reproduce the sound. when watching videos online about box building i see people say "this sub is recommended 7-8 cubic so im going to give it the full 8 as i want more frequencies to be reproduced". I have asked on here, 12v, and smd at various times and in various ways how cubic footage effects things. i have never been told that the size of the box will effect the frequencies it can reproduce and yet this very concept seems to be referenced by those who build boxes. what am i missing?

winisd clearly showed that raising the box volume would move the sub into a 30hz low end, flatten the curve out a bit, and allow the sub to hit 64hz the same as 30hz. from what i understand box volume does not effect notes but rather only effects how much power the sub needs to reach xmax. can you fill me in on areas that i do not understand?

ok so i will put my current box into a program and see wher eits at, i think i will design a new box here and rebuild it as i think i want to go from 7 to 9 cubic. its what winisd is telling me to do anyway

but i want an EQ im not confident this box is salvageable. i shall see but i dont think i can change the tuning with out loosing a fair amount of internal volume.

Pioneer P7800HD

im going ot need an EQ tho right? i should fix the box and then EQ it

ok, i wont try to wrap my head around that yet. now i need to find the EQ thats right for me

so i feel that i am now at the point of buying an EQ. my questions are: i have tweeters, mids, bass, and i might have a set of mid bass coming up. should i buy a 3 way EQ or a 4 way? how many channels is enough? id think i want at least 30 channels to eq from no? the more the better? what is the difference between a 1/3, 1/2, and 1 octave response? how can i tell if my deck is clipping the RCA signal or if a processor is clipping? to be clear i am not looking for some worthless 40hz or max volume one time measurement but i want a way to tell at a glance if i am clipping with a wide range of songs and volume configurations. i currently have a KX3 xover, would the EQ be before or after that? what else do i need to know?

i think my question is more general and maybe im not thinking of it correctly. lets say ive got a sweep now of 30-50hz. 32hz is 8db, 40 is 14db, 50 is 10db. so i start cutting gains to even it out so all 3 of these frequencies are around 8db on teh graph. now lets take 40hz; lets say the amp was putting out 3KW at 40 and the sub was moving 95% of xmax. as i remove 57% of the volume of this through the -6db EQ setting lets say the amp is putting out 1290w and the sub is moving 40% of its xmax. how do i bring the amp power back up with the flattened EQ so that the sub is utilizing its full power and also that the sub is putting out close to its full power. am i thinking of this right or wrong?

well any EQ i pick up will have a line driver on it so that's what i was thinking of. in either case. as i reduce the db on certain frequencies to flatten things out i would want to boost the over all volume up so im not putting 50% power to the sub. how should i do this?

ok, so ill start with cutting to flatten, from there can i gain across the entire spectrum to bring the volume back up? say amping the line voltage form 4 to 6v?

i have spent some time in winisd today and i think i understand what i need to do next. im going to find a db meter and find my cabin resonance. from there im going to map out an EQ plan in winisd to flatten my response curve and then im going ot build a new box, buy a 1/3 octave EQ, and see where im at.

ok so i think i need a real DB meter. i have an omni directional yamaha mic already that i think ill try and use and i found a program called REW that i will use to set a base test in the truck. when measuring output does it matter how the speakers are setup? should i use the setup i want in the final config? should i use all sealed? should i use all IB?

ok, how shall i do this?

i mapped out some EQ settings in a new box design. 9 cubic feet with a 32 hz tuning and 128 port area. Fi audio SP4 18 on a ZX2500.1 this is my first time ever looking into any EQ or using win isd to this level. im sure most of you will remember that my goal here is to get a flat responce curve with as few peaks as possible up into the 65hz range for the music i like. am i on the right track here? a gain of 3 db @ 65hz a static gain of 2db across the system a gain of 3db at 32hz a gain of -3.5db at 38hz a gain of 2db @ 50hz xover at 100hz sub sonic at 28hz air velocity is 20m/s impedance does not drop below 3.6ohm while inside of xover frequencies. max VA is 4KW @ 61hz in a very sharp peak so there may be a bit of clipping there. nominal VA is 2800 maximum cone excursion is 30mm my 31 and 60hz are the same volume with a smooth roll between them

same sub, same amps, same xover, same tuning, same port area. one box is 6 cubic feet and another box is 8 cubic feet. what will the audible difference be? i know the smaller box will require more power to move the same amount but aside from power handling does the ability to reproduce certain frequencies become effected?

another question. does cubic area effect the range of frequency? if it does at all, i know it effects power handling but does that correlate to frequency sweep?

i made a post on SMD a few months ago asking if my sub getting hot was normal and everyone said sure, its fine. its got the cooling, fully loaded, your not putting to much power to it ect. a month later flames from the sub set fire to the roof of my cab when the tinsel leads combusted. if its HOT to the touch turn the gains down, check your sub sonic filter, and make sure bass boost is off. the higher the frequency the less cooling the sub gets because its not going through its full xmax movement. couple that with a boost in power at the 40hz mark and you generate a ass load of heat.

i dont know how it started but many people say irregardless instead of regardless... its so common that the new word made it into Websters last year. it bugs the crap out of me when i hear this but it seems most people use this word in place of regardless.

yes i am, more than anything im curious to know how this effected the sound of the box so i can compare this to otehr boxes and decide if i want to double up this port or if i want to extend it to lower the tuning.