Distortion

[Grmanalishi 10+ year member]

Should you avoid using your HU volume above ~ 75% to avoid distortion? I use it at 100% and get distortion sometimes. (Using Alpine HU, ADS 246ix 6.5" comps (125 W), Diamond 661i 6.5" comps (100W), Kenwood 50W RMS@4 ohms 2-channel amp, MTX 50W RMS@4 ohms 2-channel amp.) The gains on the amps are set

I just bought a more powerful 2-channel amp (Kicker 110W RMS@4 ohms) to try to avoid distortion and I'll do the same for a 2nd amp.

Click to read more...

 

[LOUD 4DOOR 10+ year member]

If your head unit is causing the distortion, then thats what I would replace in hearbeat.

I am not sure if I agree on your amp replacement ...

 

[Stel 10+ year member]

Nearly all HU's have distortion at some level. 75% max level is a good rule of thumb, you would need an oscilloscope to find out where it actually distorts. Reset your gains with 75% max volume according to one of the gain setting tutorials listed in the sticky at the top of this forum. I'm guessing most of the distortion you hear is from the amp clipping though. You should hear improvement with the stronger amps but I would have got a little more power, around 150+ rms @ 4 ohms.

 

[Grmanalishi 10+ year member]

I've read about what clipping is but I haven't read whether it can damage your amplifier or not. When I set up the system I had all units turned down and turned my HU up until distortion started (like the guides tell you) but I didn't hear one bit of distortion even when I reached max HU volume.

 

[ThatChevyGuy 5,000+ posts]

you may not have distortion, but i bet your settings are flat...

 

[phatmatttrip60 10+ year member]

exactly what is clipping and what does it sound like?

 

[thch 10+ year member]

lets say you are in a room. 10m by 10m. i tell you to run 50m in a straight line. you can't.

same concept here. the amplifier has a limited maximum output voltage, say +-50V (625W peak, 312W "rms"). as you turn up the volume, the peak output voltage the amplifier needs to exert to exactly reproduce an amplified version of the input will also increase.

at some level, the peaks should exceed this maximum output voltage, but can't. incresing the volume further simply increases the amount of time the amplifier stays in clipping.

There are of course nuances, and amplifiers will vary in the manner in which clipping occurs, but they will clip for the same reason.

the clear indications of clipping are a shift to a "pumped up" sound with no dynamic range (all notes are loud), a lack of tranient response (notes do not appreciably decay before other notes begin), and a humming/buzzing sound.

many people cannot hear lower levels of clipping.

there are examples that can be downloaded, try google.

 

[Grmanalishi 10+ year member]

The output V of the amp can not match the input V. The sound wave actully turns into a square wave which the speakers process poorly.

Can you damage the circuit of an amp when clipping?

 

[thch 10+ year member]

yes, depending on the amp. There is extra power. The power supply will be strained. Various power semiconductors may become damaged as well, though this mod of operation can be better for some amplifiers.

amplifiers are designed to handel clipping, as it is deceptively difficult to ensure you won't clip the amplifier, due to the way filters and processors can align frequencies to produce peaks that are greater than full scale.

Minor clipping is nothing to worry about, and provides benefits to most "street" users in that it increases average SPL by reducing dynamic range. music is now louder on average. This also allows multiple tracks, recorded at different volumes, to seem nearly equally loud.

of course, at moderate levels, the tonality and the transient characteristics of the music may be degraded as described above.

At severe levels, the amplifier and attached speakers may become damaged. tweeters now receive extra power (the distortion contains high frequency content), and the tweeters may become damaged. woofers and other speakers may be damaged as well.

(also note that amp gains are best listed relative to rated output, not knob rotation. basically, the amp could attain full power output with either a high gain setting and low signal, or a high signal and low gain. because there are a wide range of HU outputs and amp inputs, percentages of knob rotation are not overly useful)

 

[XHiFiX 10+ year member]

1kHz tone, 4 seconds: first 2 seconds clean, last 2 seconds clipped - http://home.comcast.net/~dcruz523/shared/1kHzCleanToClipped.wav

100Hz tone, 4 seconds: first 2 seconds clean, last 2 seconds clipped - http://home.comcast.net/~dcruz523/shared/100HzCleanToClipped.wav

 

[phatmatttrip60 10+ year member]

1kHz tone, 4 seconds: first 2 seconds clean, last 2 seconds clipped - http://home.comcast.net/~dcruz523/shared/1kHzCleanToClipped.wav
100Hz tone, 4 seconds: first 2 seconds clean, last 2 seconds clipped - http://home.comcast.net/~dcruz523/shared/100HzCleanToClipped.wav

thanks...