Gain Crossover on an amp what do they do?

[RbAudio_Geek 10+ year member]

What does the Gain and Crossover on the amp do?

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[flakko 5,000+ posts]

arent you an audio geek? you should know!

gain controls how much power is going into the speaker

crossover gives the speaker a rolloff at a certain hz.

 

[RbAudio_Geek 10+ year member]

lol i am a geek thats still learning so i want the gain as high as possible? And what does he mean by rolloff?

thx

 

[thch 10+ year member]

gain -- signal level adjustment. similar to a volume control except that there is no garuntee you will not have distortion. you're HU will put out a signal at a certain level (at a certain volume setting that is). gain is the amount the signal will be boosted.

Typically you will see a knob with voltages listed for the gain. This will set what INPUT signal voltage will be required to get an OUTPUT voltage that allows for maximum power without signifigant distortion. thus lower voltages on this knob correspond to higher gains.

Too much gain means you MIGHT have "clipping". (depends on the source volume setting of course). if you crank the gain to the limit (lowest voltage setting), you will probably get the system to the loudest undistorted volume at a low volume setting on the HU. so long as you never turn the HU up very high, you will be fine...

Crossover -- A tonal filter designed to remove unwanted sounds from the speaker. most small door speakers cannot play bass without distorting badly, thus a highpass filter might be used to remove the bass. a lowpass filter can be used to remove or reduce vocals from the subs (which might do a poor job with vocals and make the vocals sound bad). there are many things about crossovers though.

slope -- typically this determines how tones near the "cutoff" are affected. a high slope on a lowpass filter might mean bass plays noramlly, but lower midbass, midbass, midrange and up will be reduced. a low slope means that bass would play, lower midbass would be a little reduced, midbass still noticable, and finally midrange would be fairly well cut.

frequency -- determines where you start cutting out tones. you may have a 15" and only want to play sub-bass tones and start cutting bass, midbass, ect... or maybe you have some small midwoofers that you need to play bass and midbass. higher frequencies refer to higher pitches.

 

[flakko 5,000+ posts]

lol i am a geek thats still learning so i want the gain as high as possible? And what does he mean by rolloff?thx

no set the gains using a dmm (read the sticky)

basically it cuts the speaker off at a cetain frequency where another speaker picks up. in general you want the sub to play 0-60 hz mid 60-2.5k 2.5-20k for the tweeter. thats in general not the crazy active 3 way sets pple have

 

[thch 10+ year member]

note that setting gains by the DMM is one tool. you may end up going a bit higher or lower. blindly setting gains by this method is a start -- it gives you maximum power without signifigant distortion. but this may not be your goal. in some cases you may want less then maximum power, you may not be as concerned about distortion from the amplifier, or the system distortion will be from the speaker (and in excess) in which case maximum power without signifigant distortion will be limited by the speaker even if the amp is capable of happily driving the speaker beyond its limits.

lower gain (higher voltage marking on the gain-knob) if the speaker being amplified is too loud or has signifigant distortion.

higher gain (lower voltage marking on the gain-knob) if you are not worried about damaging the speaker and can tolerate the negative effect of distortion in exchange for the (arguably) positive effect of "compression". amplitude compression is a lack of "dynamic range". basically the more you compress, the less difference you have between loud and soft notes. cranking the gain will make soft note louder, but will distort loud notes.

sonically, one can argue that the increase in average loudness is worth the addition of a little distortion. from a power point of view, you may be able to damage your speakers -- especailly if the distortion can affect speakers not made for high power (such as tweeters). many factors come into play though. there is a chance of equipment failure, and thus highly excessive gain is discouraged even if you don't care about distortion.

 

[flakko 5,000+ posts]

note that setting gains by the DMM is one tool. you may end up going a bit higher or lower. blindly setting gains by this method is a start -- it gives you maximum power without signifigant distortion. but this may not be your goal. in some cases you may want less then maximum power, you may not be as concerned about distortion from the amplifier, or the system distortion will be from the speaker (and in excess) in which case maximum power without signifigant distortion will be limited by the speaker even if the amp is capable of happily driving the speaker beyond its limits.
lower gain (higher voltage marking on the gain-knob) if the speaker being amplified is too loud or has signifigant distortion.

higher gain (lower voltage marking on the gain-knob) if you are not worried about damaging the speaker and can tolerate the negative effect of distortion in exchange for the (arguably) positive effect of "compression". amplitude compression is a lack of "dynamic range". basically the more you compress, the less difference you have between loud and soft notes. cranking the gain will make soft note louder, but will distort loud notes.

sonically, one can argue that the increase in average loudness is worth the addition of a little distortion. from a power point of view, you may be able to damage your speakers -- especailly if the distortion can affect speakers not made for high power (such as tweeters). many factors come into play though. there is a chance of equipment failure, and thus highly excessive gain is discouraged even if you don't care about distortion.

are you copying this from a website?

 

[thch 10+ year member]

nope. this was an original post.

 

[flakko 5,000+ posts]

nope. this was an original post.

woah jeez lol.... ygpm i might want ya to do something for me

 

[Shugarra 10+ year member]

higher gain (lower voltage marking on the gain-knob) if you are not worried about damaging the speaker and can tolerate the negative effect of distortion in exchange for the (arguably) positive effect of "compression". amplitude compression is a lack of "dynamic range". basically the more you compress, the less difference you have between loud and soft notes. cranking the gain will make soft note louder, but will distort loud notes.

This is only assuming distortion from the speakers at max output of the amplifier, right? Otherwise, assuming you have a decent set of speakers that can handle the power and are relatively flat you shouldn't see any kind of diminishment in dynamic range as the loud notes will play proportionally louder than the soft notes?

 

[thch 10+ year member]

going higher then the "maximum gain without distortion" point will allow the amplifier to clip. under such conditions a good speaker will accurately reproduce the distortion the amplifier has added. basically you've reached the linear limits of the amplifier. if you want the music to be louder without signifigant increases in distortion (note that amplitude compression is distortion but sometimes concidered good), well, you'd need a bigger amp.