when %thd is audible distortion?

[Dirtrider4eva 10+ year member]

a quick random question, at what THD, can you hear the distortion out of your class a/b amp through the door speakers?.

my amp is rated at .0015% THD,

and with my gain at about a knick above a 1/4th, i cant hear any thd until about 30-31/40.

but what at % of clipping/thd can a person actually hear?

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[kramer_212 10+ year member]

i dont know for sure, but as a reference i know that the smd dd1 detects it at 1%

 

[Dirtrider4eva 10+ year member]

yeah, but im curious about audible.lol. regardless distortion is ALWAYS present in every system. but what level can a person detect it is the hard part? obviously the more sensitive ears, the easier, but theres gotta be a quick area. I know it cant be above 20%, otherwise the speakers would be getting damage for sure. and im only sending maybe 100 of the avaible 250 watts a channel.

 

[kramer_212 10+ year member]

yeah, but im curious about audible.lol. regardless distortion is ALWAYS present in every system. but what level can a person detect it is the hard part? obviously the more sensitive ears, the easier, but theres gotta be a quick area. I know it cant be above 20%, otherwise the speakers would be getting damage for sure. and im only sending maybe 100 of the avaible 250 watts a channel.

don't quote me but i think i remember from awhile back 5% is audible.

 

[Jmac 10+ year member]

While driving, most people would be hard pressed to tell the difference between a song with 0.5% distortion and 5% distortion even with excellent drivers, amplifiers, damping, etc. If you use MP3s, as most people do, it'll be even more difficult to tell.

BTW, your amp's rating is simply a minimum output distortion. At rated output, it'll be substantially higher than 0.0015% THD+N.

 

[Dirtrider4eva 10+ year member]

alrighty thanks. just a quick rule of thumb is what i needed. within this next week im going to pickup a digital clamp and use it in conjunction of my amp to see what they put out. ive been o so curioso.

 

[wenn_du_weinst 10+ year member]

I'm not sure on the exact % but you can deff hear it when swapping from a 1% thd amp to a .005% thd amp

 

[Dirtrider4eva 10+ year member]

its an old Us acoustics usx 600f if that makes a difference. old school zed.

simply wanted to know a ballpark. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[West]

As a chemist (with some physics under my belt) it really depends on you defination of audible... If your talking about human ear's then that is going to be entirely dependant on the person listening to the sound. We age and loose high frequency hearing Hearing Test - high frequency sounds measure hearing loss

Personally I struggle to hear the 17 kHz frequency, but its faintly there for me and I am 26. When you first notice clipping, is entirely based on the frequency that your ears can pick up. Test your hearing to determine the highest frequence you can hear (however I am not sure if all computer speakers can produce these fequencies).

If you are talking about an instrument detecting the distortion then that is going to be entirely dependant on the abilities of that device.

You are correct noise exists and will alway exist in every audio component and everly electical device that has a voltage based output, there is no way to completely cancel noise out (from a practicle prospective). Although there are companies which try to market 0 noise cables and devices (its a lovely lie).

 

[Dirtrider4eva 10+ year member]

i hear 17k perfectly, and then 18 nothing, which i assume my computers in motor speakers cannot reproduce.

i have great hearing.

if i had an osciliscope, i wouldnt be asking, for i would know, but there too expensive for what i have.

and doing amp tests are worth nothing if i dont have an estimate on THD. sure i could probably get 1400 watts out of a aq1200d at 1 ohm, but the clipped signal would be why.

 

[kramer_212 10+ year member]

i hear 17k perfectly, and then 18 nothing, which i assume my computers in motor speakers cannot reproduce. i have great hearing.

if i had an osciliscope, i wouldnt be asking, for i would know, but there too expensive for what i have.

and doing amp tests are worth nothing if i dont have an estimate on THD. sure i could probably get 1400 watts out of a aq1200d at 1 ohm, but the clipped signal would be why.

wana burrow my o scope?

 

---------- Post added at 09:56 PM ---------- Previous post was at 09:55 PM ----------

 

borrow.

 

[martiandancer31 10+ year member]

it is frequency dependent.

 

[Dirtrider4eva 10+ year member]

Maybe, your pretty close. How would i use it exactly?

 

[BnGRacing 10+ year member]

You're probably going to hear the speaker's own distortion before the amp's. The type of distortion you'll hear quickly, and manufacturers do not give a spec for it, is IM distortion. Furthermore, most THD numbers given, if not all, are a-weighted which means that the figure is tested at a high frequency while using low power...usually it's 1 channel driven.

The real kicker is if you can hear a difference between two amps, and it's not that hard, you're hearing THD. Some amps sound phenomenal when there's a little clipping going on. Others sound like hell. Most people, and we're talking 9 out of 10 here, prefer a little distortion in their music. It sounds better to the ear despite looking worse on a piece of paper.

Listen to electrostatic speakers. To me, they don't sound right...kinda thin. It's just my ears prefer a little 'good dirt' in the music. Don't be surprised if you find you prefer a little distortion too. Go o-scope your amp with 0dB overlap and give it a listen afterward...you'll probably hate it.