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What song, or songs, are you using to tune your system? Is it possible to tune it in the garage or do i have to wait till I can get it out on the water? I don't really want to spend my first couple outings doing a bunch of adjusting, and neither does she!
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Vivaldi Concerto in G Minor for me:
http://www.youtube.com/watch?v=B1itjItO6Cs
Yes, you can tune the system in the garage. Now it will sound very different out on the water than it will in the garage but most of that is out of your control. With the correct tools, you can set all the maximum pre-clipped gains without ever hearing the system. The audible part is the level matching between highpass and lowpass. That is more of a splice over a narrow bandwidth where the garage dimensions can definitely have an impact.Quote:
Originally Posted by KRAK
David
I was kidding above. I think you are looking for this thread (and good luck!):
https://forum.moomba.com/showthread....ghlight=tuning
There will be NO KIDDING in the audio & electrical forum dammit. This is serious stuff!
Krak - there are a lot of ways to look at this question. Some boats dont get tuned at all. Some get tuned and retuned and retuned. Some boats get tuned, and then people play with Eq's all over the place on the water and make smiley face curves. My approach to tuning is like this....
In the garage -
check polarity of speakers
adjust gains on each amp
Level match bow to cabin (usually boats are over or under gained on one of these area's because of the impedance loads on the amp)
Adjust Subwoofer xover point, engage subsonic filtering (If applicable).
Eliminate bass boast on amps
setup ipod for 3/4 volume and flat EQ
Establish Maximum output of each zone (i.e. more level matching)
On the water -
Fine tune EQ and boost or (usually cut) specific frequencies.
Minor adjust gains.
Review subsonic filtering.
And surf behind the boat and see if I got my own smile on my face.
All of this can be done with tools, scopes, RTA's or just your ear. Ultimately your ears dont lie. Scopes and RTA's can help with the academic stuff. But once the engine cranks over all that stuff isnt going to help you establish the right sound for your setup.
When I do tweak and tune clinics on the water (last year I did 4 of them regionally), I'm usually mixing the garage items and water items together. Often times wiring issues and or phasiing issues (i.e multiple subs on the boat), can really slow down a tune. The term tune to me is not a good one. I try to optimize the entire system. the "tune" is going to depend a lot of the music selected by the user or bit rate the media his recorded in.
For example, when Mandley was at Exile yesterday, I think the absolute best music that played through his stereo was Michael Jackson. Fantastic recording, lots of dynamic sounds within the recording. It was just WOW impressive. Only problem with optimizing the setup for that is ---- Mike dont listen to MJ all that much. He prefers some rock and roll -- which typically has a far more compressed sound. The solution is to find a middle ground that will give a good platform to reproduce the "tunes" you play on the system. You can do lots in your garage.
-Brian
The further into the future we go, the funnier it gets, but there is still very proper reasons for using NICKLEBACK for gain setting.... Nice Pic KG... :) Let me explain.
If KANEBOATS had been serious, depending on where in Vivaldi's Concerto he picked to set his gains he probably would have set the gains too high. The reason is that there are lots of very quiet, medium and loud sections in most classical recordings. If you are setting gains with a quiet song, or quiet section of a song you will find that you will clip easily with other more normal "boating" recordings, OR that you are only using about 15% of the head unit's colume control to reach full power from your stereo.
Consider this screen shot of Diana Krall's "Quiet Nights" The dark Roarchalk Ink blot - looking thing is the actual visual representation of the music. As you move from left to right you move from the beginning to the end of the song. The lighter areas above and below the dark part represents headroom left over and not used by the recording or the recording medium. The horizontal floor and ceiling at the very top and bottom of the lighter areas represent MAX AMPLITUDE. You can't record anything louder than what will fit between the floor and ceiling of this lighter area. One can infer a parallel between this picture and amplifier or head unit clipping. If one tries to make the dark representation of the song louder such that the peaks extend above and below the lighter area's floor and ceiling, it is the same thing we describe audibly as clipping distortion. Pretend you could turn a knob that made the dark aection of the picture taller both top and bottom, so that parts of the dark waveform extended past the floorand ceiling of the white area. IF this were an o-scope pic of the amp's output you woudl see those parts outside of the white area will be clipped.
A very quiet recording would have a horizontal ink-blot thing that was very narrow vertically. A very loud recording will have a very wide ink-blot thing. Vivaldi's Concerto will have skinny quiet parts, and loud wide parts. A recording that does not have a lot of loud passage will make it very hard to set gains; if you set the amp where it clips using QUIET NIGHTS loudest section as pictured below, you will find other songs that have greater amplitude and use up more of the area between the lighter area's floor and ceiling. The amp will have been set to max clipping based on a non-maxed-out recording..... So as I pointed out above, your gains will be higher than necessary if you use this recording to set gains, and louder sondgs will clip the stereo at high volumes.
More on that in the next post
Attachment 17007
So now I am going to show you a picture of the waveform of NICKLEBACK's Animals. See the attached pic. When we look at this song, we can see that the engineers who recorded it maxed it out and compressed it to be as loud as possible. The dark Roarchalk blot is now basically a rectangle. there is very little white area left above and below the waveform of the song.
Except for at the beginning and a section at about 2:15 the song is fully filling the available bandwidth window. Put another way, there are no quiet spots..... There are no spots on this song where the "tuning music" is not as loud as it could be. You can fiddle with gains all the way through this song, except for at the two points mentioned and know you will not find a digital recording louder than this one. The analogy to a head unit or amplifier is quite literally this song is recoded at max un-clipped levels and represents a unity gain song in that it is as loud as it can be, just under the verge of clipping; this is the same thing you want from all other parts of your audio system.
If you set your gains with NICKLEBACK's Animals, you will have used basically the loudest possible recording for gain setting. You will find that you have set your gains lower than when using other tracks and you will find that you don't accidentally clip when you move from Vivaldi to Michael Jackson....
Now understand, to best utilize this capability you need to go out and buy the CD... IF you are using an MP3 recording that you did not rip yourself, you cannot be assured it is at max amplitude. There are lots of sketchy rips and copies out there, so do yourself a favor and if you buy into my logic, go get the CD and use it in your head unit directly, or if you don't have CD playback, take the time to rip a good .WAV or virtually lossless MP3 copy to use, and then try to use the 30-pin output instead of the 3.5mm headphone jack.
I hope this makes sense. I see the waveform, as I am a pro-sound and recording engineer, but for some folks, it is hard to "see" the music when presented visually. If you have any questions about what I am showing here, feel free to ask.
Phil
Kicker
Attachment 17008
loud and proud! Good song too...........
Thanks for the info Phil. That's what I was looking for, but I'll gladly keep taking other song suggestions as well.
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Don't pick your 'favorites' for tuning. Don't pick your ideal 'demo' material for tuning.
For level setting, select a clean, busy, well-recorded, dynamic artist/song with activity across the entire bandwidth. It doesn't have to be as dense as Nickelback but that is on the right track. You also don't want a selection that falsely emphasizes or boosts one area. I prefer to stay away from music with synthesized bass. Neutral is better.
I don't listen to Dave Mathews but the first cut on Crash is good for tuning. It's recorded a bit hot and reveals clipping.
David
There's always the SMD dd-1 for gain setting. There is also a neat app from focal that might help u it's called "focal teach HD" really good app if ur not sure what to listen for when ur tuning ur system. Plus it's free too.
What is the definition of clipping, when it begins to distort? Are you tuning for max amount of volume without clipping? In other words should this be done in an open field/water far away from civilization? :-D
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Depends on who your neighbors are. The HS kids across the street from me like to jam rap music out of the garage around 3 pm before their parents get home. They are huge workout guys who lift weights and stuff while they jam. If it wasn't for the lyrics I wouldn't mind. Don't like the kids asking me "what's a mugga fugga nidda, Dad?"
May have to tune the boat stereo out in the driveway at 7 am Sunday morning and have a nice conversation with their parents.
An amplifier's job is to magnify the audio signal as a faithful replica of the incoming signal. Any amplifier has limits. Consider those limits as a fixed box with a definite ceiling and floor. When the signal is expanded beyond the boundaries of the fixed box, any portion of the signal exceeding the box is clipped off or flattened out. Now, the peaks are essentially missing. And that is distortion. The crest factor is reduced which means the music is compressed without the full dynamic contrast.Quote:
Originally Posted by E4NASH
The signal changes form from one that is largely in transition to one that is more continuous. That creates a high risk of thermal induced speaker damage as the speaker is not given the opportunity to dissipate heat. An amplifier driven into clipping or compression begins to narrow in bandwidth. It can continue to put out more power but over a narrower range. An over-driven amplifier becomes increasingly inefficient consuming more power but with little additional power getting to the speakers.
So clipping not only sounds nasty but it has numerous byproducts. All of them are destructive.
David
Mmmmk...so then I am correct in my thought that clipping is distortion?
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With a test disc and a multimeter, you can find the clipped limits in total silence as long as you know the true power limits of an amplifier in advance. But if the specs are bogus, this doesn't work out. Or, the SMD or a handheld OScope can find clipping without audio.
This only establishes the maximum setting. To finish level setting and level matching, the system is going to have to play very loud somewhere.
David
Clipping is distortion, yes. It causes the amplifier's, (or other audio device) output waveform to change with respect to the input waveform. Let me show you graphically what David is saying, with the attached image.Quote:
Originally Posted by E4NASH
At the very top of this picture you see a red squiggly line. This line represents the signal, (frequency-modulated alternating current) going into any audio device. To explain a little further, high sounds like come out of tweeters have squiggles that are very closely spaced, (left to right) and low sounds like come out of woofers are very widely spaced. There is a positive and a negative voltage component to the signal. We talk about the peak voltage of any individual "hump" as its AMPLITUDE. Speakers go in AND out... positive voltage makes the motor in the speaker push the cone out... negative voltage pulls the cone in. DOing this very quickly allows the speaker cone to vibrate the air quick enough that we perceive it as sound.
Now back to AMPLITUDE. We just said AMPLITUDE can be expressed in Volts. A higher power amplifier can provide higher absolute voltages at its speaker connections. It is called an amplifier as it will take the relatively small voltage signal from a CD player or radio and AMPLIFY it to a higher voltage. Any amplifier has a max positive and "max" negative voltage that it can put out. In the picture I drew, the theoretical amplifier has its peak AMPLITUDE at +12 and -12 volts. As David shared, these two extreme voltages can be used graphically to draw a box that the amplified waveform has to fit in. I have drawn a few boxes.
In the first box, (top down) I have literally a representation of an amplifier that is delivering an output signal that is exactly the same as the original top input signal. If we had an AC voltmeter we would be able to measure the voltage coming out of the radio and then measure the voltage coming out of the amp and see that they were the same. This represents an amp where the gain is set so low that it really does no amplification. If you were viewing the amplifier output on an oscilloscope it would look very similar to this. Make sense?
Next picture down we see the waveform is taller, and it fits more tightly between the top and bottom of the box. This represents again the output waveform of the amplifier. In this second picture the gain has been raised and the amplifier is really amplifying. If using that same AC voltmeter we measured the radio's output and then measured the amplifiers output, we would see that the amplifiers output voltage is greater; it is now acutally AMPLIFYING the input signal and making it louder. At the same time, the AMPLITUDE of the waveform is still less than the + and - 12 volts that the amplifier can make. Again, if you had an oscilloscope, you would see the same amplified squiggle. Nore the tops and bottoms of the waveform still form arcs; they are rounded with nice smooth curves... In geek terms, we can say that we still have a sinusoidal waveform. This is desirable and would indicate an amplifier whose gain was probably set darned close to right at least for the speakers it is driving, not considering final level matching which David points out.
Now look at the third picture. In the third picture we see an example of a waveform that has an AMPLITUDE greater than what the amplifier can deliver on its outputs. Again, we are hypothetically setting a max +/- voltage for this example at 12 volts, yet the wafeform if fully and sinusoidally were amplified, its peak AMPLITUDE would be about 16 volts. Quite simply the amplifier cannot do that... So, any part of the waveform that would be creater than +/-12V in amplitude is CLIPPED off. Literally CLIPPED, hence the terminology. The result is that if you looked at an oscilloscope at the output of a clipped amplifier, it would look like the bery bottom red squiggle, (box removed). See how the peaks are flattened? That is the CLIPPED signal....
Now David and I have slightly different ways to explain the damage caused, but the results are the same. Let me briefly try to touch on this:
When we look at the squiggle from a time-perspective, (from left to right) we can see that voltage is constantly changing. if you pick any point and draw a dot on any of the top three red squiggles, you can then see that to the left and to the right the voltage, (amplitude) is different. The voltage is ALWAYS going up, going down, or changing from up to down, (top of the curves). This changing voltage moves the speaker cone back and forth in a controlled manner, and turns the electrical energy into sound. CHANGING voltage makes sound.
Now go to the very bottom red squiggle and draw a dot right in the middle of one of the horizontal flat spots. What is the amplitude/voltage difference on either side of the dot you drew? It is the SAME, (Here is the part where David and I diverge as I am ONLY explaining in very layman's terms what is happening for a VERY small time window). For that very brief period of time where the output of the amplifier is flattened at max voltage, the amplifier puts out what on an oscilloscope looks like DC voltage. It also acts like DC voltage. DC voltage does not change, so it does not gently move a speaker cone in and out, it drives it right out to the very edge of its excursion, and then the speaker does not move. It is stuck out there. Consider taking a small speaker and connecting a 9-volt battery to it. VOltage is still moving theough the voice coil, yet the speaker is not moving, so the coil is sitting there just heating up.
I will defer back to David now, and acknowledge that a very heavily clipped amplifier is putting out an AC square wave, and is not really putting out DC, but the analogy is a good one to help explain that for those brief moments where an amplifiers output voltage is maxed out, it behaves and does damage the same way as if one were to sinply take a speaker and connect it to a car battery.....
This is very much a simplfie layman's terms explanation of what cliping is, but I hope that the simplfied explanation makes it clearer!
Attachment 17017
Phil
Kicker
Thanks...simplified is good...that is all I need.
This thread is possible sticky material? A lot of good tuning info here.
Me do gud wif pictures
a picture is worth a thousand words they say. very good info here.