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Has anyone used an EQ to help a cross over? for example say we have a tweeter rated for 3.5-22Khz. we set a high pass cross over at 4.5Khz to give room for a 16db slope to roll off before we get near that 3.5Khz frequency range. now say you turn the stereo up and get distortion on the tweeter during bass hits so you go into the EQ and drop the 20-120hz range by -6db and the tweeter no longer distorts. my understanding was that a cross over should have taken ALL bass out of said signal before it its the tweeter. what would cause this type of situation to occur and would it be beneficial to have an EQ setup to -12db all frequency ranges outside of a speakers operating range in addition to a cross over? edit: a second question for M5 (or anyone who can answer it) I was told that some artists are going back to vinal records as they produce more accurate sound than digital. now i know an MP3 cuts off lots of frequencies we cant hear and such but the way it was explained to me is that an MP3, WAV, AC3, any digital audio is not capable of producing multi stage harmonics that one would get with an analog music source such as a record or at a live concert the dynamics of the sound waves from the instrument projecting off various surfaces in the hall. is there truth to this?

is there any truth in that having a head unit that you can turn off its internal amplification can provide cleaner sound through its RCA's than a head unit with its internal amp remaining active?

when you put batteries in the rear of the truck i would recommend welding some 1/4" plate to the frame rail opposite the fuel tank at the front of the bed. (its where most people have exaust). I put my batteries there and there is also room for a 30 gallon air compressor tank under there if you need it. i would say this is the best place to have extra batteries.

lol, yea thats what i mean. i juts want to learn the right thing once, not have to keep going back and fourth and fact checking everything. i suppose there is something to be said about doing research to better understand what you are being told but when work cant even get something as simple as how an electron moves through copper in a DC power circuit it sort of throws that out the window.

my installers at work use their experience in competition as a reason why pretty much everything i have said in this thread and am over thinking is worth while digging into. The competition world is the same as the install world of normal radios as far as i am instructed with the exception of less volume. I do see now how they differ from one another, i only wish i had someone in the shop with a background more like yours so as to not leave me second guessing everything all the time. I do intend to fully grasp the loud speaker cook book but given as im only a few months into car audio its a challenging read to put into practice conceptually. once i get into more car audio builds and start playing with various types of speakers im sure it will become more apparent to me. the reason i had asked about the audio control clipping lights is that in their guides audiocontrol states that you wont clip any signals if you use their products and my installers also tell me that those lights are all you need to ensure you are not clipping.

the source reference for the cab noise measurements comes from the audiocontrol manual for that RTA. take that with a grain of salt i suppose as they are trying to sell their product in there. The education you have M5 explains a lot. I have yet to personally meet any audio installer who is able to tell me information that checks out scientifically. from how electrons flow with skin effect to how speakers perform in various environments. I am reading the loud speaker cook book at the moment and getting information from it but i dont yet know how to apply that to real world. i figure once i have read the book 2 or 3 times i might have a better grasp on things. those amps and processors that have "clipping" LED's on them, do they do anything useful? such as audio cubed amps and audio control processors?

if i play a 50hz (or any tone frequency) and find its clipping point will not the sub respond differently at 40 or 70hz? in other words the resistance of the coil changes with the excursion and thus the amp will be at 4ohm at frequency A but at 60 ohm at frequency B. to that end wouldn't you need to go through at every tone to test for the amp over driving as its power output is dynamic? or perhaps pick the frequency in wich the amp will be producing the most power and then tune from there? in a sealed box that could be determined from the specs of the sub but wouldn't you need to test the SPL from a ported box to know when the sub was at its peak level and thus when the amp is pushing the most power?

The starting point of the RTA was to measure my trucks road noise and standing resonance frequency to know where my dead zones are and know what frequencies i need to over power. it was with this information that i was told to set my cross over slopes to cross in the dead zones of my truck so that i am using the naturally acoustically dead frequency octaves to hold my lowest cross over slope and thus loose as little of the audible signal as possible. is there any truth behind this? The RTA was also said to be a much better way to set gains than an O scope is, the debate and discussion of Oscops effectiveness at measuring anything relating to a clipped musical signal withstanding is there any merit to the point of an RTA being better than an Oscope in this regard? it was also stated that a 1Khz tone should be used when using your ear to listing for distortion due to its place in the octave scale (or something along those lines) (its easier to hear when it enters clipping than other signals). any truth to that? yet another installer swears by using target voltage to set an amp by combined with a 2nd person in the trunk (or infront of the sub) listening to distortion while playing say a 60hz track.

well im working on learning more but it is "trying" to ones mental state when you need to sift through so much misinformation and i find myself CONSTANTLY "knowing" one thing only to find out it is not correct. what did i quote that is not in the cook book? also i point out 2 sources - loud speaker cook book and audio control manuals (as in the company). can you enplane what S/N is on amps vs on speakers? i think i understand what it refers to as far as a speaker is concerned but on an amp does it not refer to the amount of power the amp must reproduce before it is capable of minimizing thermal and electronic noise? about the input gain of an amp - I have read and heard that going crazy with gains will blow up amps and subs, fair enough if you drive anything into massive clipping its going to blow shit up. I was later told and found references to it that the gain on an amp is designed to match output voltage of a input signal. so a 5V signal will have a gain of 1DB where as a .5V signal will have a gain of 10db (numbers are arbitrary). then when discussing this with the installers at my shop i was told that the gain knob of an amp is used to increase the output of said amp and does not increase the input voltage in any way. Having high output voltage from a HU is required to push high fidelity sound due to its ability to over come thermal noise and to provide the amp with a high quality and voltage signal to amplify from. the issue i find i am running into is that the MECP really does not cover much more than basics and it is more a general 12V guide than an audio guide. also i find that many manufactures contradict things that are listed in MECP. further more i have experienced people who have been working in the industry for longer than i have been alive that yet contradict manufactures and MECP (not necessarily at the same time). add to that the topics in the loud speaker cook book are very advanced for a beginner and while i have been around long enough to have destroyed some of my own audio/electrical equipment and now am seeing others destroy theirs it is almost entirely on "what not to do" that i base any of my comparison knowledge. i feel that there is no where except perhaps an electrical engineering course that one can truly learn what is or is not bull shit. I am sure that each source has its own reasons for writing what they do and I am confident that at least some of the information is accurate but it is so difficult to know what is or is not correct with out going into the real world and testing things. This is one of the reasons i want to have a scientific device to compare my ears and results to so that i have a solid benchmark to hold all my information against. its not unlike giving someone information on how to make damascus steel but the individual has no education on thermal dynamics or basic elements. more over he has no reference to quality control of impurities int eh metal. he can make the steel and forum it but when he goes to roll it over into say a twisted block it "may" hold together until hardening when it shatters due to the impurities from not having a high enough temperature. with out some sort of thermometer showing him the temps he is working with and his ability to see this one is to hot or this one is to cold he is not able to simply "feel the metal" to know if its working or not. I am so unequivocally displeased with the phrase "tune it with your ears" that i could scream. YES i can tell when a speaker is deep into clipping by the range of the frequency but i have no idea if the head unit is correct, if the cross over is correct, if the amp is not powerful enough or if the speaker is maxing out. I have zero frame of reference to gauge my ears from and this is why i want/need some sort of mechanical device to show me this. I want to learn the advanced audio and electronics and i want to get to the level of a true professional installer, this is hands down the hardest field i have attempted to educate myself on. harder than general contracting, computer repair, IT networking, database design, even program languages. all of this has set notions and scientific premises from load bearing beams to EMI regulations on networking cables but i feel as if car audio is bereft of such guide lines and is left up to various people speaking out their ass on the topic. Perhaps this is due to the plethora of "expert" sites and guides to the topic or the profit margins to be found in the field. in either case i am well and truly frustrated - im going to go research sub enclosures for my truck now... Ps - M5 where did you get your training or education on car audio? if you dont mind me asking.

I am in the works of building a 10-12KW system with a single dedicated 420A next to my factory alt on an isolated bank of AGM's. we shall see if mechman is correct in that 3 AGM's and 1 HO alt can handle it. to be fair he did state "such a configuration would be fine for 2 or 3 songs at max but not for constant playing at extended periods"

i didnt copy and paste anything. i was expecting a long responses pointing out all the ways i am "wrong" or have been mislead actually. i typed all of that based on what i currently believe is correct from what i have been told/read from various sources.

reading up on documents such as loud speaker cook book and audio control manuals i find that not all amps are grounded from PCB to their cases and thus in high power amps this can turn their cases into EMI antenas and cause interference in the other components around it. what is a "pot driven EQ"? the gain of an amp does not amp the input voltage, it amps the output voltage of the amplifier. once the voltage from the HU or line driver is on its way towards the amp there is nothing in the amp that will change it. Thermal noise should be addressed from the HU if possible or from the processors prior to the amp as a second choice. (at least this is what i have learned from audio control and my shop). I do not know how to describe what i am after with any other terms than a SQ setup. I want to go from 60% efficient amps and 70DB S/N to 80%+ efficiency and 90+ S/N so as to require less power, provide cleaner signals, and have better response. I also want to go from the massive peaks and vallies of frequency response that my crachendos have to a more level (although not flat) response curve through each speakers xover band. I want to gain volume, loose distortion, and get more efficient over my present system. The SA3055 is far more accurate than anyone's ears could ever hope to be. I am using this to find my cab harmonics and find my dead zones of standing waves. my intent is to place my Xover slopes so as to intersect at these null points in my trucks acoustics so as to place the dead zones in the dead zones thus loosing as little "hearable" signal as possible. I do not yet know how to fully use the device yet but have been reading its manuals today and have found it very interesting and seemingly more accurate than using any kind of oscope for such things. my main focus is to ensure my HU is not clipping signal to my processor and my processor is not clipping my signal to my amps. there is simply no way to know this with my ears as each device is not emitting its own audio tone to hear and this device is designed for just such a task. as for not having a serious shop i just do not see the market for it. I would love to be able to learn all the splitting edge of advanced audio work but you know what i get on a daily basis at work? "hey man i want to build a system in my Cadillac, i want to hear it from blocks away" me - all right, well whats your budget 3 or 4K? "awww hell nah man, i can spend like 500.00". no one i have met wants to drop money on audio. most advanced thing im doing in the near future will be some fiber glassing for a custom sub box into a car whos make/model eludes me atm. from what i hear however the Hopkins area still has people willing to spend some money.

yes you can run 5K on that truck with 2 batteries. you can also fit group 31 or 49 in there if you want to break the sides off your battery mount under the hood. a HO alt is required however. mechman runs a 220, 240, or 320 for that truck with out modifications. you can get higher but you need to build a custom mount for it. mechman states that 3 group 49's with a 320A alt will handle 10K rms DD. when you order let him know you have the cummins and you will get a slightly smaller pully on it. If you have modded your engine with over fueling and boosting and thus have lower rpm you will want to request an even smaller pully.

Has anyone on here ever used a computer as an audio processor? I want to have a rockford 3 sixty style audio processor in my truck and was thinking that i have spare computers and i have heard of people putting imacs in there cars in place of decks so that got me thinking into what expansion cards/audio programs are out there for such purposes? anyone have any thoughts?

I am looking for specs on efficiency and THD for .5,1,2 ohm applications of the Q13500D.1, basscleff 5500, and sundown sa2 5000. while these manufactures list there 4Ohm and even 2 ohm on some, none of them seem to have any detailed specs on 1ohm loads and as for sundown i cant seem to find ANY specs to speak of on their website so im some what leery there. does anyone know that the exact THD, signal to noise, and efficiency is at 1ohm loads for these amps? thanks.

there are a few ways to do it to be sure, I am looking to have the option to dial in all aspects of my install, from cross overs to eq bands. to that end i am looking for a full range cross over and a full range eq for each output. at present i am looking at a 3 way setup with JL mid bass and hertz mid range/tweets. the polk audio amps im looking at have full range cross overs built in so that eliminates the need to have a processor with additional cross overs. I have a simple 5 band (or maybe its 6) on my HU so that is still a requirement for me. to that end i am looking to have a 128+ channel EQ for my system to configure the bands on each individual output to my bass, mids, and highs. now that you know exactly what i am looking for do you have any thoughts on programs or recommended sound cards? for a more detailed idea this is where i stand with my rebuild parts list, i have about 3 days of reserch into it thus far: JL audio mid bass - ZR800-CW 140 per 280 totalamp for mid bass and mid/tweet - PA D4000.4 280.00 mid range/tweet: hertz esk 165.5 90.00 subs: Team18 X2 1600.00 amp for subs: ? batteries: 220.00 group 27 alternators: mechman E series 370A with downsized pully. X2? 700.00 plus fabrication.

im looking for the basics, EQ and cross over. although the more i look into the amps/speakers im looking for the more i think i may not need a cross over. the amps im looking at seem to all have full range xovers built in so perhaps just EQ. so i would be looking for an independent EQ for each RCA out. my question above was does it matter what kind i need? if i build a computer for said processing then i should be able to add a 16 or 500EQ band or 10 additional cross overs as i wish all in software once the hardware is built no? so from that sense it would mostly come down to a software program that can handle processing and a sound card with a few ins and outs. would it just use 3.5 to rca i take it? perhaps i could even grab a deck with SPDIF to computer, would eliminate group loops *shrug*

well if its me building a comp with software id think i can add or subtract as i wish until i get what i want. my thoughts would be a high end sound card and i have a drawer full of cards in my apartment here. everything from stereo to 8.2 channel with optical ins and outs. so what software would you think to control the xover and EQ?

I am pricing out a 2500W rockford amp to upgrade from my kicker 2500.1 does anyone have one for sale and if so for how much. secondly would anyone be open for a trade? i have a 2001 1500 dodge ram 4X4 that im not using.

I would like to ask this question as a thought experiment to determine if I am properly understanding the following relationships with wiring and power. Our speakers get AC out of our amps and our amps get DC from our power system. The DC power does not have frequency as it is a single flowing direct current and as such the flow of electrons through any wire have ZERO skin effect as skin effect is only applicable with frequency of transmission. What does play a part in power capacity however is the material of which the wiring is made of and how it is made. The total measured DC resistance of a cable of X size will be lower in copper material than it will be with aluminum. Also the resistance of said wire (given that it is the exact same diameter) will be lower with a single solid strand than with a multi stranded wire. Wire used in AC systems such as our speakers will gain resistance with frequency and will also increase its skin effect with frequency. Our subs normally operate from 20-120hz (in most installs) and thus the skin effect of signals even up to 150hz leaves a skin depth of .244" useable on the cable. this means that in a 1" diameter cable that only 1/4 of it would be useable for current transfer. Given that most of us (myself included) use only up to 8GA wire (for amp to speaker) and given that 8ga wire is .1285" in diameter that there is no conceivable way that skin effect will play any part in the transmission of power through this wire. one would need to be at 550hz or greater to the sub before the very center of this 8ga wire would no longer be used. In mid range and tweeter applications we use much smaller wire say perhaps 16ga for mids and 24ga for tweeters. this puts the skin effect at 118% the diameter of a 16ga wire for the mids and 102% for the tweeters. in this scenario there is no way that I can envision skin effect will have any bearing on the power requirements for signal transmission in car audio. Now in power wires we have CCA and OFC, CCA being aluminum wrapped with copper and OFC being supposedly 99.9% or greater free of oxygen and being pure copper in construction. If one were dealing with high frequency AC current the CCA or even CCS would not matter as the copper on the outside would be the only part of the wire to see electron flow however in our car audio application it is the thermal inductance that factors into the CCA wire. meaning that the CCA wire is 25% less conductive than the copper wire due to aluminum having ~25% less conductivity than copper and a greater propensity for capacitance. thus given 2 runs of identical gauge wire but one being CCA and one being OFC and both having 80% of rated AWG power handling capacity the CCA wire will reach a temperature considerably higher than the OFC and thus will have a greater resistance to the flow of electrons and deliver less power to the amp with a greater demand on the electrical system. edit: it is recommended that the ground for the amps be less than 3' long. why does this matter as the frame or body it is grounding to is much greater than 3' in length. would not a run of wire to the battery terminal and a ground to the frame that leads to a ground to the battery be the same thing as it is roughly the same distance?

a few days ago it was about -28F outside and i had my radio maxed out from when i arrived at work. when i left i started my truck and forgetting i had the volume up i didnt turn it down before it started to play. i got about 1/4 of a note out of my sub and it stopped playing, tonight i pulled my sub out of its box to find one of the tinsel leads broken in half. i soldered it back together and the sub works now but my amp does not. my KX2500.1 powers on but there is no AC voltage out of its terminals. i assume the sub caused some degree of arcing on the amp. how common is it for subs to blow apart due to cold weather? now obviously my case is max power at very cold temps but still, given that the forecast is for -25 - -38 for the next few weeks id like to know more about how sub zero temps effects the amps and such. ill pull my amp apart later this week to check it out.

i am still unclear on a few things, the discussion has continued on another forum but i wanted to throw this up here to maybe get some more speciffic car audio people to chime in on what i might be wrong about. from what i gather using litz wire will allow each individual strand to have its own surface area and thus greater capacity for current due to the skin effect being limited with in each strands jacket. so a litz wire would have a much greater capacity for current transfer than a stranded or solid core wire but at what frequency would this take effect? in the 10's of mhz or into the ghz range? if i have a 10ga sold and a 10ga stranded is it true that hte solid will have greater capacity due to the lack of air pockets in the wire (taking 12V DC voltage or >1mhz frequency)? and secondly would it be true that the stranded wire would behave with skin effect as many individual wires or would the outside area of the entire stranded bundle be what gets the skin effect? so in other words would each one of the 150 strands have its own independent skin effect going on or would the 10ga wire as a whole have just 1 skin effect? (assuming the frequency is with in a range to allow for skin effect, say up into the khz or greater range). i want to get some documentation of all this and print it out so i can be sure i fully understand all of this. then i want to sit down with my boss and get this all straight as what he is telling me is contrary to what im told on here and what i have found with my own research. EDIT::: after much research tonight i have come to the following conclusions, please correct them if they are wrong: solid wire is cheaper to make and smaller in diameter than stranded wire. for short runs stranded wire is better than solid when it comes to load capacity but at longer distances the solid wire is more durable, better protected, and due to skin effect vs increased resistance on the line it is preferred over stranded. (solid wire has less resistance than stranded). most homes use solid wire due to the termination needs of outlets and receptacles having ports designed for solid wire. i can not find any codes in my local or state area that stipulate in wall wiring must be solid so long as all receptacles are approved for solid or stranded termination. the skin effect depth changes based on the resistance of the wire so it is not a uniform measurement that can be applied to any gauge of wire but must factor in the relative inductance along the line. with that in mind however it seems that a 21ga wire would have next to no negative effects caused by skin effect at 20khz due to the skin effect being at minimum the rough diameter of that wire. at 100hz for a subwoffer on AC the minimum skin effect would be .22" and an 8ga stranded wire is .128" in diameter so in that application skin effect would still have no bearing. is this correct? rapid fire Q/A:stranded wire must be large diameter than solid core to have the same load capacity? only litz wire provides a skin effect benefit due to more usable skin effect surface area? solid wire is cheaper and more durable than stranded which is why its used so much in homes? skin effect should never be in the discussion with pure DC current as it plays no part? if by the math the skin effect depth at 10khz is .029" and a cable of .028" diameter is used the skin effect will effectively use the entire wire just like a DC signal would?

i dont think the KX has fuses, im assuming the PCB is screwed but i wont be able to remove the amp untill this weekend. its a good hour long job to pull the amp out. ill see how well i can do fixing it myself and go from there. i kinda wish kicker would put fuses in there, would save so many blown amps.

i unplugged my sub yesterday and noticed that running my mids/high amps cause my lights to dimm very slightly when bass hits. when an amp draws power it is producing a spike draw on the entire vehicles system wich it is not designed for as there really is nothing else on a car that will pull such a bust draw outside of cranking. how common is it to see a slight dimming of lights on audio installs? i ask because to me it seems that with 2 large batteries and a HO alt i would expect not to see any dimming regardless of volume level. now the wiring is good and i am certain that all my grounds/contacts are properly terminated. i am looking more into this as I am planing to add a great deal of extra draw on my electrical and id like some thoughts on what im looking to do. My understanding is that such a setup is used in competition but not so much in daily drivers. My thought is to make 2 separate electrical systems. take the factory alt/batteries and leave them as is with no after market audio hooked ot this outside of the head unit itself (or perhaps the head unit should also be on the same circuit as the amps?). Take my 320 mechman and upgrade it to there 400+ model (i was told my a local starter/alt rebuild shop that anyone who claims an alt for my vehicle is putting out more than 210A is lying there ass off as it is not physically possible to go beyond that, I intend to bench test my mechman to see if it is truly doing rated power) assuming it is worth it of course and moving my current agm batteries to the back. hooking the after market alt and 2 agm batteries directly to one another with an external voltage regulator and then hooking all my amps to those 2 batteries. i would simply add 2 cheap lead acid batteries under the hood to use for normal vehicle stuff. now would i still want to ground out to the frame OR would it be preferred to run dedicated wires for ground to the alt and amps making sure to isolate the alt from grounding to the rest of the truck? basically is it a bad thing to mix 2 independent electrical systems grounds? my thought is that i could then have a dedicated set of batteries to power my audio and i could ensure no ill effects due to voltage drops or spikes on the rest of my truck. additionally i could also go up to a 15 or 16v system quite easily in the future if i chose to do so. open to thoughts and recommendations, thanks.

my understanding of the external voltage regulator from mechman is that it controls the alt's charging all by itself (exciter wire included). would this regulator be capable of determining when its over charging the batteries and cut out or would it just stay on at what ever voltage setting 100% of the time?