PLEASE tell me hes wrong

[Wonderbread 5,000+ posts]

One more. The info posted on the last page was ripped straight from http://www.bcae1.com/ . Go there, use it, love it.

 

[RandyJ 10+ year member]

The reason distortion (as in a distorted signal, not a bastardized note) kills subs has to do with the shape of the sine wave. Grab an O-scope and play a tone. You hopefully get a nice clean smooth sine wave, with rounded peaks and valleys. If you dive an amplifier into clipping, you basically give the wave a square peak at both ends. The area under the curve (your power) is greatly increased. You get more power then you are expecting and can accidently push the driver into either mechanical or thermal failure.
THAT is what kills subs.

Hence, thermal abilities surpassed. A distorted signal will be tolerated, even if it is a full-blown square wave, in certain situations, as long as the coil does not overheat or the motor overexerts itself.

I'm sure you know this, I just wanted to make sure that others do not read that and just to the unfortunate conclusion that distortion will kill any driver under any circumstance.

 

[Spkrman]

You didn't read my first post appearantly, yet you tell me I'm incorrect. The gain on any amplifier DOES NOT control the power output of the unit as far as how much it'll output. It simply matches the input voltage of the source to the amp itself. on a 300watt amp, you can turn the gain all the way up. It'll produce 300 watts at a certain volume. You can then turn the gain down (all the way) and the amplifier will still be able to produce that same 300 watts. The difference will be that the signal from the source unit (volume) will have to be turned up louder for the amp to recieve a stronger signal.

Yes, the gain *does* control the output.

I have a remote gain on my kicker amp, and you know what I do when showin off, I turn the HU to a certain level, and turn the remote gain up... making the remote gain a volume control.

The gain is a volume control, no matter how you use it.

 

[NDMstang65 10+ year member]

It is a relative to the signal input voltage of the amplifier, not a volume knob.

If it were a volume knob, why can't you turn it wide open without distorting and square waving the output voltage?

 

[Cris 10+ year member]

so if there's a amp w/ 300w max, if you set the gains higher will there be output of more than 300w?

This is what I think is the root of this gain-understanding problem. If you set the gains higher on an amp than they should be, then YES.. it WILL produce more than 300 watts. Companies rate what their amps are capable of producing based on a certain psychologically pleasing distortion rate. If you accept a higher distortion rate, the amp will output a higher amount of watts... hence why turning up the gains may yield higher performance, but a higher risk of damaging both your subs & amp that are not thermally prepared for it.

a watt rating is NOT a CAP of how much an amp will produce. It's simply how many watts it will produce at a standardized distortion rate. It also denotes what range an amp will behave reliably at. It's not an exact science.. hence why some amps owned by idiots with gains turned to max will last for years.. and other amps at normal temperatures only slightly over-set will fry up.

 

[DBfan187 5,000+ posts]

An amplifier gain control (input sensitivity) is simply an level-matching device allowing you to match an amplifier's input circuit to a source unit's (or signal processor) output. Ideally gains are set so an amplifier's output "clips" at the same time the source unit "clips".

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That's what the gain control is for. Nothing else.

 

[NDMstang65 10+ year member]

Yes, the gain *does* control the output.
I have a remote gain on my kicker amp, and you know what I do when showin off, I turn the HU to a certain level, and turn the remote gain up... making the remote gain a volume control.

The gain is a volume control, no matter how you use it.

You've made some dumb comments my man, but that sir takes the cake.

I'll be ****ed if i'd let you within 50 feet of my car with a screwdriver.

Go back to your hole particle board boy - don't bless us with anymore of your misguided intelligence. You've already done enough with telling kids particle board is fine to use...don't start with this crap.

 

[DBfan187 5,000+ posts]

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[Spkrman]

It is a relative to the signal input voltage of the amplifier, not a volume knob.
If it were a volume knob, why can't you turn it wide open without distorting and square waving the output voltage?

You can turn the gain up all the way with no input and it wont make any more distortion than with it getting no input at 0 gain.

Which, I ran my 2500d at full gain all last year, and for casper this year... and it worked fine...

zx2500 same thing

When I set the HU to a certain volume, and turn up the remote gain on the amp... its, a volume control.

Signal:

Source ------------------ HU -------------------- AMP

You could very well take the HU out of hte equation, and guess what... you can use the gain to control the volume. I've actually done that in HT on a few occasions...

Now, if you use it to control volume, its... *drumroll* a VOLUME CONTROL.

 

[NDMstang65 10+ year member]

Hey dipshit

Measure the voltage coming out of your headunit.

I bet that's why you can run it wide open.

It's not a volume control, it is relative to input voltage.

Buy an O-scope and prove to me i'm wrong. You get any sort of headunit with decent voltage output and you clip the immortal hell out of it.

You can't take the headunit out of the equation...its where your signal voltage is coming from.

 

[RandyJ 10+ year member]

This is what I think is the root of this gain-understanding problem. If you set the gains higher on an amp than they should be, then YES.. it WILL produce more than 300 watts. Companies rate what their amps are capable of producing based on a certain psychologically pleasing distortion rate. If you accept a higher distortion rate, the amp will output a higher amount of watts... hence why turning up the gains may yield higher performance, but a higher risk of damaging both your subs & amp that are not thermally prepared for it.
a watt rating is NOT a CAP of how much an amp will produce. It's simply how many watts it will produce at a standardized distortion rate. It also denotes what range an amp will behave reliably at. It's not an exact science.. hence why some amps owned by idiots with gains turned to max will last for years.. and other amps at normal temperatures only slightly over-set will fry up.

If you turn the gains "up" (actually decreasing the numerical value on the gain), then your amplifier will create it's rated power sooner, but begin to distort the signal afterwards.

The only way it will yield higher performance is if the gain is set wrong for your listening habbits.

 

[RandyJ 10+ year member]

Hey dipshit
Measure the voltage coming out of your headunit.

I bet that's why you can run it wide open.

It's not a volume control, it is relative to input voltage.

Buy an O-scope and prove to me i'm wrong. You get any sort of headunit with decent voltage output and you clip the immortal hell out of it.

You can't take the headunit out of the equation...its where your signal voltage is coming from.

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[RandyJ 10+ year member]

Since no one wants to read, I will post this for everyone to see. It's apparently too hard to click on a link and read for once....

Amplifier Gain Controls:

Contrary to popular belief, an amplifiers gain control does not determine the maximum power that an amplifier can produce. As long as the preamp/drive signal has sufficient level, the amplifier will produce its maximum power output level. The gain controls are used to match the amplifer's gain to the gain of the other amplifiers in the system (in the case of a multi-amp system). The gain controls also allow you to match the amplifier(s) to the head unit. Not all head units have the same maximum preamp output voltage. Some head units are capable of producing 9 vrms out while others are only capable of 1.5 vrms out.

Please note that a head unit will reach its maximum output level (clipping) well before the volume control reaches the upper end of its range (usually at a point of 85-90% of its maximum range). This is especially true of tape decks, not because the audio section is of lesser quality but because some tapes are recorded at lower levels than others and the manufacturer must design the deck to be able to produce a sufficient output level with virtually any tape.

NOTE:

This example uses a rotary volume control instead of the digital type pushbutton controls but the same basic concept applies.

The output of some decks will clip at less than 50% of its full volume when the loudness is engaged or bass and treble are boosted. Many of the low to mid priced head units have a maximum output level (before clipping) of 2 vrms. If a 100hz test tone is played in the head unit and the bass control boosts signal levels at 100hz by 10dB, the output would clip if the pre bass boosted signal would have been .63 vrms. In other words, If the output of the 100hz test tone is more than .63 vrms and the bass control was turned to its maximum level, the signal would clip. This would very likely be at less than one-half volume.

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Note:

The red arrows (near the volume controls) in the following drawings are showing you the position of the volume control which will produce the maximum (without clipping) output voltage. The test signal would be a tone recorded at its maximum level. This first section principally applies to tape decks.

The diagram below shows the approximate position of the volume control which will drive the amplifier to reach its rated power. Notice that the gain controls are set at 5vrms. The head that only produces 1.5vrms cannot drive the amplifier to rated power. The head unit rated for 9vrms drives the amplifier to its rated power with its volume control at approximately the '10 o'clock' position (which will make it difficult to adjust the volume precisely). This would not be an acceptable gain setting for either head unit.

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This diagram shows the gain control set to 9vrms. The head unit capable of producing 9vrms would be able to drive the amplifier to its rated power. The 1.5 volt head unit would not be able to drive the amplifier to its rated power. This would be a good setting for the 9vrms unit but would NOT be good for the 1.5vrms unit.

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This diagram shows the gain control set to 1.5 volts. At this gain position, the 9vrms head unit will drive the amp to rated power at a very low volume control position. The 1.5vrms head unit can drive the amplifier to rated power and would be an acceptable gain position for the 1.5 volt head unit.

As you can see, the gain controls match the head unit to the amplifier. No single gain position is right for every head unit. There are many factors which must be taken into account when setting the gain controls in any audio system. Setting the gain controls so that the amplifiers were never driven into clipping with the 0dBfs 100hz test tone would likely leave you with a system which would not produce sufficient output with a typical music source. The previous example is only to show you the relationship between the head unit output and the amplifiers gain controls.

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This section applies to CD players more than tape decks.

Note:

This demo assumes that the test signal is a sine wave recorded at the highest level possible (0dBfs). It also assumes that all tone controls are set flat and the loudness coutour is switched off.

This is essentially how a system should be set up. The head unit should be able to use most of its range before the amplifier is driven into clipping. Again, if the gains are set too low, the head unit won't be able to drive the amplifier to its maximum output level. If the gains are set too high, the amp will be driven into clipping at a very low volume level (on the head unit).

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Clarification of Terminology:

Generally, when someone says that you need to 'turn the gains up', you need to make the amplifier more sensitive. When you make the amplifier more sensitive, it will take less input signal to to produce a given amount of power. The confusion comes in when you look at the gain control markings on the amplifier. If they are marked in volts, it's generally the amount of input voltage that it takes to produce full power. When you turn the gains 'up' you turn the gain control to a 'lower' (smaller) number. For example, the gains are higher at 2 volts than they are at 4 volts.

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And to show it in another way...

At the risk of being redundant, the following diagram shows how the output of the amp relates to the output of the amp at different gain settings.

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This calculator will show you how the gain settings control the output of the amplifier.

You may manually enter the gain setting, input voltage and speaker load.

This is based on a hypothetical 100 watt/channel amplifier.

The gain setting is the amount of input voltage which will cause the amplifier to reach maximum power.

Notice the signal status indicator

Notice how much quicker the power goes toward clipping when the gain value is set at lower values. Remember that the gain tells you how much input voltage will cause the output to be driven to clipping.

Data Input:

Gain setting? Volts

Speaker Load? Ohms

RCA Input? Volts

Data Output:

Output = Volts

Output = Watts

Signal Status:

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This is another gain control calculator. It's fairly self-explanatory. One note... If the tops and bottoms of the amplifier sine waves go out of view, the amp is clipping. If the demo is too small, click HERE to make it fill this window. Use your browser's 'back' button to return to this page. The right negative is inverted because the amplifier is bridgeable (as are most amplifiers on the market) and the signal output is on the right negative. The bridging terminals for many amplifiers are the left positive and right negative.

Does not make sense, then check out the very helpful diagrams here:

http://www.bcae1.com/gaincon2.htm

 

[RandyJ 10+ year member]

Here, once more for those who are blind.

http://www.bcae1.com/gaincon2.htm

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[Spkrman]

Hey dipshit
Measure the voltage coming out of your headunit.

I bet that's why you can run it wide open.

It's not a volume control, it is relative to input voltage.

Buy an O-scope and prove to me i'm wrong. You get any sort of headunit with decent voltage output and you clip the immortal hell out of it.

You can't take the headunit out of the equation...its where your signal voltage is coming from.

HT setup...

CD player ------- pre-amp ------ amp

your car...

cd player circuitry ------ pre-amp ----- amp

The pre-amp is there to boost/regulate voltage from the source, and to make life alot easier if your running more than one amp.

The preamp in your head unit is also relative to input voltage, input voltage from the cd player, tuner, or any other SOURCE.

//content.invisioncic.com/y282845/emoticons/crying.gif.ec0ebefe590df0251476573bc49e46d8.gif :crying: //content.invisioncic.com/y282845/emoticons/crying.gif.ec0ebefe590df0251476573bc49e46d8.gif sux to be wrong doesnt it.