setting up line driver

neverman · Post by **neverman** » Sun Mar 08, 2009 11:40 am

Just checked, the dmm is good from 40hz to 1khz.

The clip light on the ZPX2 functions as a voltage detect circuit correct? It supposedly comes on when it "see's" 11 volts. I doubt that's where the signal is actually clipped. At any rate I was surmising that the circuit detects 11vac not a value of 11vac rms. Circuits aren't designed or set to RMS values from what I remember. Once a threshold value is set and then that value is exceeded the light would come on. So for me to set a threshold on a sinewave up around 11 volts, I'd adjust down based on my RMS value read which is .707 of 11vac... no?

In other words once the sinewave broke through +11vac on the positive wave the limit light would come on. Assuming we're going both sides of zero here, we may not be? In car audio are we riding on a positive bias baseline or do we have negative rails too? Anyway, that limit light isn't tied to a true clipped value. I'm sure they left some headroom in the circuit right? It's more of just a "whoa" sign warning you to go carefully from that point on is what I'm trying to convince myself of. Otherwise they'd never want that light to come on as any clipping is bad. At least in my book clipping is bad~

My head's starting to hurt... maybe I should stick to surfing porn on the weekends?

Post by **ttocs** » Sun Mar 08, 2009 6:02 pm

so have we been able to decide what would be the best tracks to listen to? music, noise, what freq?

neverman · Post by **neverman** » Sun Mar 08, 2009 7:06 pm

I just loaded all of the Focal disks onto my ipod in lossless. Gonna give them a good listening. I suppose this is in anticipaton of my system being back to normal when I get my mids working again. I have a huge hole where the midbass should be at present. Drivers hopefully showing up this week.

It seems odd to me still that the theory revolves around relatively flat tracks instead of dynamic ones. I don't think a normal passage should ever clip (when you're close to proper set-up) it's those peaks I worry about. Signal to Noise...

gkitching · Post by **gkitching** » Mon Mar 09, 2009 8:58 am

ttocs wrote:
gkitching wrote:
ttocs wrote:my ears are the most important and the most expensive tool in my tool box. After almost 15 yrs installing it has been carefully calibrated to be able to troubleshoot multiple problems at once, on the fly with out needing to worry about making adjustments and being in the correct mode. They can spot an out of phase speaker from 30 ft and hear the beginning of the signal when it is clipped and I have never found a meter that can do this.
OOOOOOOOOO

What are you one of those guys thats like 5' - nothing with a Napoleon complex that feels the need to turn every conversation into a big dick contest?

Well you win .. You're a big dick!
Wow, I am really speachless on this one. No, I am 5'11" and 160 and use to not being the tallest or the shortest. Are you the kid that took the names of the kids that did something while the teacher was out of the room?

I think I will stand on the point that it would take one to know one to be polite, and the kindly ask you to sit back and drink a BIG FUCKIN CUP OF SHUT THE FUCK UP! You can post your comments on someone elses post with the idea that if you don't have anything nice to say THEN SHUT THE FUCK UP and stay off my post.

back on topic. I also agree that dynamic songs like a metalica or tool would be a good idea after it is tuned to make sure that the peaks do not go to far but while tuning it would be better to find something that is more consistant. That is why I thought that a white noise track would be better for watching the peak light on the PLD1 as it would be a ver definite point where it would come on and off. I will adjust the gain on the amp by ear as I always have.

I'm sorry ... How's this?

OOOo you're great! let us all bow to worship your true awesomeness! Is that better?!

Na .. doesn't work for me. I've never been one for Political Correctness. I would rather not waste time like that so I just say exactly what I think. And your comment about being a 'tattletale' is very interesting considering YOU were the one threatening to report me to the administrators of the Insider forum for re-posting something from that site. In your politically correct way. Hippocrate! Please! Just because you say it nicely doesn't mean you're not still rude and insulting. Ohh .. I know what you're gonna say ... "you have a right to your opinion". That's another load of crap that has become increasingly accepted on the internet. People trying to justify being an asshole by stating "I have a right to my opinion." And no, I not saying people don't have the right to express themselves. But there is a difference between opinion and someone vomiting spew simply to see their typed words in public.

Sorry but nothing pushes my buttons more then these Circuit City and big box installers who come out acting like they know everything (not that all are that way). Especially ones that make those type of proclamations! You can spot an out of phase speaker at 30ft? BULLSHIT! You can hear distortion at the first db of clipping? BULLSHIT! What's worse is you actually think people believe that. And that's were my problem lies. I take that thinking as a personal insult to my intelligence! You obviously think I and the rest of the members of this phorum are too stupid to know any better.

Why is it you even come to this phorum? You are (unfortunately) part of the biggest collection of 12volt professionals gathered on the internet at the Insider Forum. You can get your questions answered by the most knowledgeable people in the business over there. So why come here? Is it because you are a little fish in that pond and you feel the need to be more important so you find a forum you feel has lesser minds just to make you feel bigger? Or is it because you've worn out your welcome over there? (Don't bother answering because I really don't care .. Really!)

To the other members of this phorum, please accept my apology for being such a drama queen. Those of you who know me, know I'm not typically like this at all. I come here because I have GREAT respect for the intelligence and passion for audio here. But this guy's attitude and comments are insulting and belittling and for that I have no patience. The sad part about this is because of this guy, I've come to realize there is no 'Ignore List' on this phorum. It's sad because I've never had to look for it before.

gkitching · Post by **gkitching** » Mon Mar 09, 2009 8:59 am

So now that I've disrupted some otherwise good debating, I'll add what I can. Not that I claim to know it all by any means.

First, dynamic range of a recording means the difference between the quietest passage and the loadest passage of any given program material. Not the overall output level of said recording. To which Metallica and especially their newest 'Death Magnetic' recording is quite possibly the worst example for a recording with high dynamic range. Or any 'pop' recordings coming out these days.

Recording media (ie; cd's dvd's magnetic tape, etc.) has a limit to the strength of signal it can store. And it's easy to understand that just about every studio out there is pushing that envelope with every pressing it makes. That Metallica cd is good thou if you're interested in hearing what happens when the recording level exceeds the media's capability. Few studios still do quality recordings with dynamic range anymore. Mainly because dynamics don't equate well with MP3 compression and Bose wave radios. Truly dynamic recordings still have the same peak output signal a squashed 'top 40' type recording will have. It just also has quieter passages.

As far as setting gain structure, you want something that will produce the maximum output signal that your system will ever see. I've always used PINK noise. Mainly because it covers the entire freq spectrum and therefore I don't have to worry about 1 particular recording being strong in 1 freq range vs an other that may be strong in an other freq range. And not all PINK noise recordings are equal either. Case in point, the 2000-2001 IASCA cd was originally pressed with the pink noise track clipped! And after it was discovered they dropped RTA scoring unitl the new cd was released.

Good studios to look at are Sheffield Labs and Chetsky Records. Generally those will have the best recordings. Their test and set-up cd's are well worth investing in. They can teach you allot!

Post by **stipud** » Mon Mar 09, 2009 10:11 am

My further thoughts on the issue...

To set gains, you want the -0dB (aka MAXIMUM output) of your amplifier to be matched to the output pre-amp signal of your linedriver/headunit. This way you can replicate the full input signal with as much power as possible, without exceeding the maximum output and causing clipping.

Dynamic tracks
If you missed the youtube video I posted last time, make sure you watch this now:
http://www.youtube.com/watch?v=3Gmex_4hreQ

I do not think using a highly dynamic track for setting gains would be a good idea. First of all, the base level of the recording is very low, so it would be impossible to use this to find your -0dB reference. Only the dynamic peaks (the very tips of the drum hits) reach -0dB, so you would have to ensure they are unclipped. However, hearing audible distortion for a dynamic peak lasting less than a millisecond is nearly impossible. At best you'd have the clip light to work from, in which case you might still have clipping even if the light doesn't go on, since it is such a short interval.

Flat, compressed tracks
Something highly compressed and loud, like the new Metallica CD, or Pop Radio would be, surprisingly, better. Have a look at this video:
http://www.youtube.com/watch?v=DRyIACDCc1I

As you can see when it shows the CD playing, the whole track is nearly at -0dB. So it would be much easier to increase the gains until you hear distortion on the whole track, instead of random dynamic drum hits. Similarly, some -0dB bass rap songs would let you tune your subwoofer gains.

Test Tones
Test tones are in theory perfect for setting gains. It's a full simple -0dB sin wave signal, so clipping is immediately and easily obvious. The only problem is your speakers. Test tones played at full volume are extremely loud and push your speakers to their limits. I have seen many speakers blown this way, even when running for short bursts, so I do not recommend using test tones with the speakers connected.

A test tone with a multimeter is a fantastic way to tune standard amplifiers. It's very simple math to figure out the correct voltage, and you simply tune to that point. This method is foolproof, assuming the amp is rated properly. It will have no trouble reaching that voltage, and you will have your gains set quickly and safely.

Pink Noise
Pink noise is great, because it has an even amount of frequency per octave. This lets you set gain across the full spectrum. The only downside is that distortion is less apparent, because pink noise already sounds like distortion, so it's hard to hear what distortion is intended and what is not.

Conclusion
So all in all, I still recommend the DMM method for setting gains. The DMM is far more accurate than anyone's ears. If you want to tune some headroom into your gains, simply use a -1dB, -2dB or -3dB test tone instead.

Now if you absolutely insist upon setting gains by ear, then I would recommend starting with pink noise, and following up with loud compressed music, and finally dynamic recordings.

neverman · Post by **neverman** » Mon Mar 09, 2009 10:44 am

I killed my battery in about a min playing that damn 60hz signal and the 1khz signals. I mean it went quickly compared to my usual tuning sessions. I normally start my car but I was just checking voltages real quickly, that was all she wrote.

Ok, I'm seeing the benefit of recordings with less dynamic ranges. One concern is.... will I reach cone excursion limits during those peaks I'm now ignoring? Are they so quick that it won't damage the drivers?

What voltage should I see out of my ZPA0.5's? 2ohm bridged for subs and 6ohm for Diamond comps?

I'm gonna use the Focal tools disk a bit today and see what there is to see.

On the 60hz, car on battery power I was getting like 30volts at 3/4? That sound about right? Sadly, my laptop doesn't even make a peep during 60hz~ My PC downstairs with the klipsch Promedias does~

Post by **stipud** » Mon Mar 09, 2009 10:59 am

Neverman, I answered most of your questions in the other thread:
http://phoenixphorum.com/post97151.html#97151

You might have to disable one amp while you tune the other, if you find your voltage is sagging too much. Typically though, I have no problem getting any PG amps to produce their rated power at 12v.

Regarding playing loud music to set gains... As long as you work from the lowest volume up, you shouldn't have any problems. Even if the amp's power exceeds your speakers, most speakers can handle additional power as long as it is unclipped (just be aware that they will be thermally affected). Unlike test tones, music varies the frequency and pacing enough to allow the speaker some time to cool down. I wouldn't recommend doing it for extended periods of time, but any speaker should handle it for a few minutes at the very least.

I remember running 250w through a $20 pioneer paper whizzer cone 6x9 just to see it blow, but it ran for 20 minutes before I gave up and forced it into clipping. As soon as that signal started clipping, the speaker died within a minute. Here's an interesting read about that:
http://bcae1.com/2ltlpwr.htm

4Nine · Post by **4Nine** » Mon Mar 09, 2009 11:36 am

Stipud thanks for basically elaborating on the FAQ's section post
of "setting gains w/dmm"...

You made things so much easier to understand.

Thanks
AL

gkitching · Post by **gkitching** » Mon Mar 09, 2009 11:56 am

Awesome right up Tom! I wish I had seen that 'loudness wars' clip along time ago. Would've saved me hours of explaining in the past. It's true that a picture is worth a thousand words.

Here is something to throw into the mix. While I agree wholeheartedly with the DMM set-up procedure for say setting maximum output for a single amp system or maybe an SPL set-up, what happens in multi-amp active systems? Seems as though if all amps were set this way, then the overall system balance would be dictated by the power of each drivers' amplifier.

For example, using an active crossover in a 3-way set-up with 3 different 2chnl amps. In theory, if we used this process to set gains on all the amps, then we would need to get amps that put out exactly the right amount of power to each of the freq sections to get a good balance.

Looking at it this way, it would probably be best to use the DMM procedure to set the amp/speaker comb. that will be working the hardest. Then set the remaining amp channels based on tonal balance. In other words, if we are using a TI500.4 to run 75w x 4 to mids and tweets and a TI600.2 for subs, then the channels used for Mids would need to be set this way (assuming they will be working the hardest) and the chnls used for tweeters somewhat less and subs maybe set to max with the DMM and then use the LPL to tone it down for balance. Of coarse that would give you the ability to let it rip when the urge arises.

Post by **stipud** » Mon Mar 09, 2009 12:12 pm

Of course... you only use the DMM to find your max gain, then you can lower this any way you like to achieve your balance, as long as you never increase beyond the maximum. Personally I prefer using faders, or lowering the output on the EQ for the specific channels, before touching the gains.

gkitching · Post by **gkitching** » Mon Mar 09, 2009 12:24 pm

Yes! This is why I've always loved the MX3i. Independent L/R control too!

thedeal7235 · Post by **thedeal7235** » Mon Mar 09, 2009 7:31 pm

i just stepped in, and wanted to add, since ive tuned my system via the dmm setting with a 60hz sine wave, A.-Ive never blown a speaker(usually id blow tweeters)(however, u cant really tune/set the tweets this way , or i cant b/c i run my tweets active @ 3.15khz-so i just keep the amp gains all the way down on my tweet amp-made sure the tweet amp is getting 8volts to it, and my mids and subs were all tuned to the 60hz sine wave, sounds great, ask dbincognito, he heard my system over the weekend, and all i use are 2 10rsdc subs off of a rsd 1200.1 ported, a zx500 for mids, and a zx475ti(75watts rms to my tweets)- i dont care what my line driver leds are showing me, cuz my dmm doesnt lie-good luck, and to date that is the best method ive found( i used to think i could tune the system via my ears-boy, i was WRONG!-good luck, and HAVE FUN, thats what i try and do

Post by **ttocs** » Mon Mar 09, 2009 8:20 pm

wow- greg your a bigger tool then I thought. I never threatened to turn you in to the insiders forum for breaking their cardinal rule. I was asking if you were on there, if you were aware you were breaking the first rule of fight club and what would happen. I was going to invite lambros over and he or any of the other hardcore members COULD have kicked you out sooner then you knew it if they wanted to, and still could. I still will not turn you in although I have no idea what a tool like you is doing on there.

I brought my question here, rather then there because I thought it would be nice to get the opinion of some PG experts. I Will say again that I do not want your opinion, keep it to yourself and maybe when you can act your age it will be worth something.

As for trying to make me out to be a lessor installer by saying I am from a big box you couldn't be further from the truth. I am in at the very end of my install now having covered most of my panels and I would love to see your reaction to a "big box installers" daily driver but to be honest I don't care how bad you want it. I am going to post pics on the insiders as well, but I would expect a much more profesional reaction there then you have shown here. you have proven that you have a need to force your worthless opinions and personal attackes where they are not welcomed. I will now tell you, not ask you to keep your opinion about me or my skills to yourself or feel free to pm me if you feel the need. You have provided nothing but drama to my honest question so once again please just shut up. If you dump on it again then I will ask the admin to start deleting it, I hope that you do not make them clean up after you like a 5 yr old.

Post by **fuzzysnuggleduck** » Mon Mar 09, 2009 8:54 pm

I'm with stipud on this one. The technique he describes is about as good of any that I've heard of which doesn't involve a scope.

waynehead · Post by **waynehead** » Tue Mar 10, 2009 4:43 am

ttocs wrote:wow- greg your a bigger tool then I thought. I never threatened to turn you in to the insiders forum for breaking their cardinal rule. I was asking if you were on there, if you were aware you were breaking the first rule of fight club and what would happen. I was going to invite lambros over and he or any of the other hardcore members COULD have kicked you out sooner then you knew it if they wanted to, and still could. I still will not turn you in although I have no idea what a tool like you is doing on there.

I brought my question here, rather then there because I thought it would be nice to get the opinion of some PG experts. I Will say again that I do not want your opinion, keep it to yourself and maybe when you can act your age it will be worth something.

As for trying to make me out to be a lessor installer by saying I am from a big box you couldn't be further from the truth. I am in at the very end of my install now having covered most of my panels and I would love to see your reaction to a "big box installers" daily driver but to be honest I don't care how bad you want it. I am going to post pics on the insiders as well, but I would expect a much more profesional reaction there then you have shown here. you have proven that you have a need to force your worthless opinions and personal attackes where they are not welcomed. I will now tell you, not ask you to keep your opinion about me or my skills to yourself or feel free to pm me if you feel the need. You have provided nothing but drama to my honest question so once again please just shut up. If you dump on it again then I will ask the admin to start deleting it, I hope that you do not make them clean up after you like a 5 yr old.

Dude for real I have to say something I cant stand it anymore cause I know everyone else out there is about fed up. If anyone is a tool its you. Throwing YOUR opinions around like that are plated in gold. If you are half as good as you are in your mind you probably wouldnt be here. If I could hear a clipped signal before audible distortion and catch an out of phase speaker from 30 ft away or whatever then I would take my skills somewhere and use them. gkitching notcied just like everyone else that you put yourself on a high horse and he called you on it. I commend him. Now you are throwing a fucking tantrum

Youve insulted the great people on this phorum enough, this is a place to help people, a place to come together and discuss opinions not try to inforce them because you think you are some sort of prodigy. I understand getting pissed off when someone steps on my toes

but for real its gone to far sweep the sand out of your vagina and contribute to the phorum or beat the fuckin bricks somewhere else where other niave people can learn your ultimate tuning by ear method. Just tell them to make sure they buy woofers with replaceable soft parts as anyone adjusting their gain by ear that turn around and listen to some jeezy or someshit will burn their VC to dust. O but you can hear distortion at like .0001 percent right. I forgot. You ought to go work for McIntosh Labs. They hate distortion and they could probably learn something from the great ttocs.

waynehead · Post by **waynehead** » Tue Mar 10, 2009 4:47 am

Sorry stipud I couldnt help myself. I dont usually get into peoples spats but I felt personally insulted.

I also apologize to any visitors reading this thread to try to LEARN something. This stuff is childish. I hope that the good info on this page shines through the ignorance.

waynehead · Post by **waynehead** » Tue Mar 10, 2009 4:55 am

Man that video on loudness war makes me want to cry. Thats why I dont listen to most popular music. What can we do to change this stupid fad and is the newer formats like sacd and dvda falling to this stupid practice? And does anyone know is this medium will settle into car audio anytime soon.

Post by **ttocs** » Tue Mar 10, 2009 6:57 am

I will keep my opinions and my questions to myself. Sorry to offend.

waynehead · Post by **waynehead** » Tue Mar 10, 2009 7:23 am

hey I flew off alittle too hard too man I aint mad at ya. I just dont think we should all be so opinionated. Im sure you have an ear for audio, Im sure alot of us have an ear for audio thats why we are so obsessed with it. I myself am a musician and I have a good ear for pitch. But, that didnt all come naturally, it took time. Anyone who spends time listening to music and striving to make it sound better is going to develop a good ear for tuning and alot of techniques to do what is needed. That doesnt meen you have bionic hearing and are too good to use a dmm. I know the best way is an Oscope but woudlnt you like the peace of mind that at a -0db pink noise signal your amp isnt clipping. Music cant excede -0db. So you can set it with a dmm and be safe. You might not get the last inkling of gain out with clipping but you are safe unlike tuning by ear. When you run with alot of headroom like I do you gotta be safe. You asked a question, many members answered to the abilities along with myself and you scoffed at us. Shit happens, attitudes arise, lets all be cool. Its all good, shouldnt be any hard feelings that cant be softened. Lets be cool

Post by **fuzzysnuggleduck** » Tue Mar 10, 2009 7:29 am

Yes, let's be cool. Tempers easily get heated (especially over the medium of the Internet) and there's really little reason for it. We're all mature adults, aren't we?

Drama sucks, we've been through it before and it was a giant waste of everyone's time.

I vote for no drama.

Post by **stipud** » Tue Mar 10, 2009 8:31 am

Haha. You're all tools!

Ttocs, you did come off as a bit arrogant, first by scoffing at us (and not just in this thread) for using a DMM to measure gains (which I still argue is far better than doing it by ear), and second by claiming you have the hearing of Superman. Personally it was a bit of a

moment for me, but I would rather argue the topic rather than arguing with you.

I am not surprised that Greg and the others were less impressed. There are so many big egos in car audio, and this forum is our only safe haven from them. We like to rely on science and good debate, so that people can decide for themselves what they think best option is. We're not the kind of people who just follow someone like sheep because they have been an installer for 15 years, or 30 years, or 1000 years. Nobody learns anything this way. So please, instead of waving around credentials, use your brain, and back up your statements with a sound argument instead.

Now it's obvious Greg came off a bit harder because of some drama about the 12V Insider forum... let's just leave that at the door. That forum is no secret anyways... they do a very poor job of hiding their server requests, so when my HTTP logs have hundreds of hits from that site, it's hard not to notice. I am sure both you and Greg are more than deserving of your membership there. Greg is definitely the most talented installer I know, and I am sure you are very good as well.

Ttocs, I'm not trying to scold you, because I understand you are the new guy. If you would like to fit in here better, please try arguing as if everyone was an equal. Then your and their credentials don't matter, and you can simply argue the topic. One you start dick waving, instead of arguing the topic, you will try to make yourself seem better, or your opponent seem worse. Nobody gets ahead in these kinds of debates.

To Greg and the others; if you don't like the way a new guy is acting, please try to lead by example rather than ridicule. If they continue to persist in their poor behavior, THEN we can start sissy fighting.

So what do you guys say... group hug?

dwnrodeo · Post by **dwnrodeo** » Tue Mar 10, 2009 8:37 am

waynehead · Post by **waynehead** » Tue Mar 10, 2009 8:44 am

you're a towel... err i meen a tool.

Post by **stipud** » Tue Mar 10, 2009 8:45 am

waynehead wrote:you're a towel... err i meen a tool.

No YOU'RE a towel.