balance/SQ, lossless line voltage?

[ncc74656 2]

I am using a audiocontrol 3055 to tune my system once its parts arrive. I like the kicker KQ30 but it has 1 in and 1 out for RCA. this would make me think i need to have amps with pass through. if i am outputting a 0.2V signal from my HU to my KQ30 and a 8V out of the KQ to amp 1, 2, 3, 4, and 5 would amp 5 have a 2V signal or a 8V signal? how many amps can i daisy chain in this manor before i run into issues.

 

secondly i have a KX3 that i do not believe i will need but if i end up using it would i run into a SQ issue having HU > EQ > Xover > amp? would that added processor cause issues with sound quality?

 

a third question is if i am to have all my amps/processors on a MDF platform would i want to run a strap or cable between their chassis to ground for noise purposes? 

[///M5 2,833]

No. You need to straighten out the rest of the guys at your shop, they are confused.

1) Don't use the SA3055 it isn't going to help, train your ears.

2) I really like Kicker stuff, but buying a pot driven eq in this day and age if fucking stupid unless you get it ridiculously cheap. Even then, I'd sell it and run something else.

3) Huh? I don't even follow your question, but notice you are confused about h/u voltages. You can plug into as many amps as you need if the gain makes up for the difference and doesn't get noisy. No direct answer like 4 or some shit as every amplifier has a different capability in the gain knob before creating thermal noise. If you don't have it, you are fine. If you do, more voltage will help...or less gain.

4) Use good connections, doesn't matter how many; however, dumb to use that set of gear. Get an all in one processor or don't bother.

5) You don't want SQ. Don't ask for it. Describe what you actually subjectively mean, not some arbitrary term

6) Why would you add a ground to something that is grounded? If you have a ground problem more grounds is NOT the way to fix it.

[///M5 2,833]

Sorry if that came out pointed. I get super frustrated with the serious lack of knowledge at ANY install shops in Minneapolis. We have so much great stuff here to not have a shop sucks.

[ncc74656 2]

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.

[///M5 2,833]

How many different things did you copy and paste there?

[ncc74656 2]

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. 

[///M5 2,833]

When you start off quoting the Loudspeaker Cookbook and then talk about a topic not even covered it doesn't leave a whole lot to discuss.

The first sentence of your next paragraph makes no sense. "the gain of an amp does not amp the input voltage, it amps the output voltage of the amplifier." As by definition ALL that an amplifier does period is amplify the input voltage.

S/N ratio's on amps isn't a spec you should ever read. It is 10000% meaningless.

Going after an arbitrary efficiency rate (that isn't based in reality btw) is nonsense. Backwards goal, look at it the other way around. And efficiency changes will not "give you a better response" or "a cleaner signal".

The SA3055 is a joke of analyzer and will only confuse you. Your whole ideas with nulls is nonsense. Why you car about something you can't hear is confusing since this is a stereo that is made for YOU to LISTEN to. The SA won't help you find clipping either, not even close. Again your ears can.

Serious shop? I don't care about that, I want serious employee's. It is a shame when there is absolutely nothing of value for me in any shop in town. There is nowhere I can even reference ANY of my friends to go for anything. Flat out embarrassing.

[Fi 4 life 0]

I've ran into the same thing in Minnesota (im just east of Cloud) its a terrible place to try and audition speakers, makes me really rely on online information and the rare car audio shows like sound set.

[///M5 2,833]

Land of educated people and culture and no car stereo shops, lol

[ncc74656 2]

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.

[SpeakerBoy 64]

A gain is used to match line out from the HU.

Most amps I've had for example, are sensitive from 0.2v-5v (many amps have different ranges) which means, any head unit outputting at least 0.2v is enough to achieve max output. It will sound the same as a 5v preout to that amp, it's a sensitivity adjustment yo.

Crossovers protect speakers from playing too high/low not necessarily where the speaker is 'heard' in the car. Adjusting frequency response not aim.

Using your ears to tune it is only logical, because that's your reference under daily driving scenarios. If you need all those devices and shit to be able to know when your amp is being roasted or your speaker is dying at xmech, you need to invest a little time in learning before you accidentally blow up a couple grand. This isn't calling you dumb, it's just meant to help!

I know how hearing the same thing over and over is irritating. But sometimes it's what we need to hear.

At the end of the day, I wouldn't ask a question if I already knew the answer

The board is here to learn not burn.

Edited February 19, 2014 by SpeakerBoy

[Impious 1,476]

 

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?

Speakers don't have a signal to noise ratio, so not even sure what you are referring to there. Signal to noise ratio for electronics is exactly what it says....it's the ratio of the signal to the noise, typically expressed in decibels. Divide the level of the signal by the level of the noise and then convert that to decibels. So if an amp,has a SNR of 90db, then the signal is 90db louder than the noise.

Noise in an amplifier is typically a fairly constant level independent of the level of the signal. Which means by default the signal to noise ratio will get worse as the level so the signal decreases. You can see this in most THD+N graphs for an amplifier, at low power levels the THD+N is typically worse because the noise constitutes a higher percentage compared to the level of the signal. It also means it's very easy to fudge SNR.....just increase the level of the signal, and magically the SNR gets much better. An amp might be rated for 100w, but if the manufacturer wanted to fudge the SNR they would increase the power beyond 100w so the SNR looked better or that particular measurement.

NOW HERE'S HE REALLY IMPORTANT PART.....any amplifier you would purchase has a high enough SNR to not matter. Literally it doesn't matter. You WILL NOT hear a difference between them. The SNR of the amp just has to be better than the SNR of the environment, and our environment sucks. Ignore SNR completely. The numbers are easily fudged, and even if they weren't modern electronics are good enough that SNR simply does not matter.

 

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. 

A gain control is used to adjust the input sensitivity so that he amplifier will provide full power without clipping. Don't make it any more complicated than that. The gain control doesn't increases the output of the amp. It basically allows more (turning it up) or less (turning it down) of the input voltage to pass through to the amplification stage so that full power is provided without clipping. Don't worry about it beyond that. Yes allowing more or less input signal voltage to pass will affect the amplifiers output, but don't think of it like that.... I think it's confusing you. You are overthinking it. The gain ratio of an amplifier is fixed...I.e. the amplifier provides 20db of gain. The gain knob is there to adjust the level of the input signal so after 20db of gain is applied the amplifier is producing full power without clipping.

Your installer is an idiot. Ok, fair enough a high gain setting resulting from low voltage might allow thermal noise to creep in. Everything else he said about "high fidelity sound" and "provides a better voltage to amplify from" is nonsense. Utter fucking nonsense. Aside from the potential for thermal noise preamp voltage has ABSO-FICKING-LUTELY NOTHING to do with "fidelity", "better for the amplifier", "sound quality"' etc. NOTHTING.

 

 

 

That AC unit is extremely limited in usefulness, and not much use if you don't understand what it's telling you in it's usefulness.

[ncc74656 2]

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.

[puscifer2 27]

In theory setting gains with an o scope and test tone is a good idea. However how much music do you listen to that only plays one note? Guys chasing numbers only would find that method useful but in the real world on a daily driver it gets you nowhere. Add to that most music is distorted by design. Think about it guitars and synths and such are passed through distortion pedals to achieve a sound the artist wanted. Trying to listen for distortion by sitting in front of the speaker is futile. Even at low volumes it's still there. Now listening for overdriving a speaker is easy. That's why it's repeated to set gains by ear. It's the most accurate method.

[SpeakerBoy 64]

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.

Wire up your sub and play a 50hz tone, use your ear to find the clip point, then back it down a bit. I usually find the clip threshold and then back it down a bit more than needed to keep it nice and safe should voltage issues arise, or anything really. No tools needed.

[ncc74656 2]

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?

[lithium 358]

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?

 

Unless you got some source for it, this sound like nothing more than someone's cooked up rule-of-thumb bullshit. The sentences don't make any sense to me. 

 

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?

 

Both are useless for setting gains.

 

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.

 

some people use a test tone while setting gain by ear. i'll just quote something from another thread. i'm surprised we dont have something stickied. 

 

 

If you are using a 0db test tone with the DMM method of setting a gain (the "JL Audio" method), then yes, output will suffer. It's an extremely conservative gain setting because (ideally) you would only be able to obtain full power output from the amplifier with a 0db signal.....which rarely ever occurs in actual music.

If you feel more comfortable with the DMM method, you can use a test tone recorded at a lower signal level, for example -6db. This will allow for higher average power output with music while still providing a reasonably low level of clipping during musical peaks.

The other method is, of course, to set the gain by ear. I normally still use a test tone so driver stress is more apparent.

 

Edited February 19, 2014 by lithium

[puscifer2 27]

Your still over complicating this. Run gains at max for all the amp cares. When you hear stress in the system, turn the volume down. Problem solved. Unhook the RCA from the amp and put a dmm in its place. Now play music, the voltage will change with the music being played. I highly doubt you will see whatever the h/u voltage rating claimed. ( not saying this is an accurate way to do this as the meter won't react in real time to the music) Most people play something they listen to a lot, turn the volume up to about 3/4 volume and tweak the gain till stress is heard. When you do back up the gain a bit. If on another song you start hearing stress on the system. Again turn down the volume. It's not as hard as people make it seem.

Edited February 19, 2014 by puscifer2

[lithium 358]

In theory setting gains with an o scope and test tone is a good idea. However how much music do you listen to that only plays one note? Guys chasing numbers only would find that method useful but in the real world on a daily driver it gets you nowhere. Add to that most music is distorted by design. Think about it guitars and synths and such are passed through distortion pedals to achieve a sound the artist wanted. Trying to listen for distortion by sitting in front of the speaker is futile. Even at low volumes it's still there. Now listening for overdriving a speaker is easy. That's why it's repeated to set gains by ear. It's the most accurate method.

 

clipping is fine until its audible. that "In theory" bit is just an argument used by people who don't understand what they're talking about. 

 

however, I agree with you're conclusion. 

Edited February 19, 2014 by lithium

[lithium 358]

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?

 

it doesn't really matter. if you do it for a few tones just pick the middle one. remember you set the gain at about 75% volume so for songs that are recorded at a lower level you can just turn the volume up a little higher. you should be always listening/smelling for problems while pushing the subs to their limits. 

Edited February 19, 2014 by lithium

[///M5 2,833]

Ps - M5 where did you get your training or education on car audio? if you dont mind me asking.

I have no knowledge of car stereos. Competed briefly in the late 80's early 90's, but am a Physicist with a concentration in Acoustics. For the past 15 years I've done Acoustic & Vibration consulting and sales.

And now you understand my frustration with the car audio scene here. Everything you have heard from ANYONE working near you is wrong. Your post is so full of confused information it is scary. I am not writing another book. Let's take one topic at a time. We will help, but this is crazy.

As for the analyzer, it won't show you shit. There are so many variables in the measurement it is bound to fail. I have a $100k acoustic analyzer sitting on my desk at the moment and all it would do for you is make you draw the wrong conclusions. You will seriously have confused measurements and come up with other ridiculous responses using something, in particular when it is that piece of shit.

You want to scream by using your ears, but what do you listen to your music with? Why would you want to do anything that you can't hear? What will you do when the analyzer tells you to make changes that you don't like? And yes, that will happen guaranteed. Even if I brought a real analyzer over and measured you'd still not like what it tells you. Add to that the error and confusion in understanding windows, aliasing, impulse, fft, phase response, discerning reflections, standing waves and measurement positioning, compensating for standing waves on the diaphragm, direction, and I could go on and measuring will only net you a false security in something that isn't real. Not a good idea.

[ncc74656 2]

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? 

[lithium 358]

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? 

 

i'm not familiar with the clipping circuit design but it doesn't matter either way. think about it, clipping (distortion) is only an issue if you can hear it. 

 

(if anyone feels likes explaining the circuit design or linking something for me to read that would be great) 

[lithium 358]

if the cookbook is too technical or if you're just interested in reading check out bcae1.com. it has some javescript examples that might make some topics easier to learn

Edited February 19, 2014 by lithium

[///M5 2,833]

Clipping indicators are in general a joke AND unnecessary. What part of if you don't hear it, it doesn't matter don't you get? You keep trying to come up with ways to make your system better than your ears. Why? In particular when you won't like better since it will sound worse to you. Completely bassakwards.

I used to carry around a binaural head and torso simulator. $30k for the body, $5k worth of mics. Even using that with a stellar analyzer is not going to gain YOU anything.

Stop using other peoples goals and things you read on the internet as something YOU want and instead use your ears and decide what could be better. If you never take the time to train your ears, then you will never appreciate anything anyways. Training your hearing is the best and worst thing you can do. Best in that it is a stellar skill and gives enjoyment worst because it makes other things sound like shit.

I've taken 16yrs of classical guitar lessons, 4 years of upright bass lessons, 6 years of voice lessons, 16 years of piano lessons, 4 years of jazz piano lessons (from Ray Charles pianist ), played in countless cover bands ranging from Reggae to Metallica, orchestra's (including the MN state orchestra), jazz bands and ran a sound board in a club for 4 years. I can whistle 1kHz nearly dead nuts with no reference, tune a guitar closer than any electronic tuner I've used by ear, and yes it makes what I do discerning. That is an education that will do more for you than reading ANY book or time on the internet. Stop avoiding letting your ears grow up and start embracing it.