Blind Test

[QUINNY]

Hi everyone.

I'd be very pleased if you could take just a couple of minutes out, to sit the blind test that follows. Please don't look at the meters on your playback equipment, waveform or any other method which may help you arrive at an answer, other than using your ears to judge.

The link is approximately 1 minute of music that has had the recorded level progressively taken over the 0dB level at which clipping occurs. It was then saved as that file and subsequently normalized to -0.1 dB. This methodology works, as when I deliberately took the levels to a peak of +24 dB, saved that file and then normalized back to -0.1 dB it sounded distorted to hell.

So all you have to do is listen (it WILL get progressively louder sounding) and tell me at which point clipping (distortion) begins. All answers before the actual time will be discounted, as it's obviously not possible to be clipping before 0 dB was originally reached.

http://www.zshare.net/audio/10907499a3b966c6/

[needlefingers]

How sad and insecure an individual you truly are.

You're not here to tell us you're right; you're here just to tell the rest of us we're wrong.

Well here's your answer. Distortion begins everytime you post.

Maybe you do have the ears of a bat, but you also have their eyes. How else could you be so blind?

[canadiantire]

To me, the sound pressure noticeably augment at 27-31 seconds.

Even though there might be clipping occurring before, I start to notice it at around 42 seconds within the low frequency of the voice.

p.s.: You can try to submit this blind test to Stevie Wonder


- Marcus

[Dayna]

Orders large popcorn and diet Dr Pepper.............

[QUINNY]

Originally Posted by canadiantire

To me, the sound pressure noticeably augment at 27-31 seconds.

Even though there might be clipping occurring before, I start to notice it at around 42 seconds within the low frequency of the voice.

p.s.: You can try to submit this blind test to Stevie Wonder


- Marcus

Thanks for participating.

[canadiantire]

Will you eventually post the answer?

[QUINNY]

Originally Posted by canadiantire

Will you eventually post the answer?

If I get more than a few peeps listening to it and commenting, yes. Otherwise it will be pretty useless as an attempt to guage, whether or not, digital clipping is such a problem as has been mooted by a certain member. I'll let you know by private message otherwise.

[remicks]

*****


I don't have the best equipment nor bat ears ..... but to me it sounds a bit more fuzzy around 38 seconds ..... but overall my impression is that it just seems to be getting louder ...

*****

[RobbaDobba]

Originally Posted by needlefingers

Well here's your answer. Distortion begins everytime you post.

Ouch.

Though I am inclined to agree with the above posting (way to welcome Ben Liebrand, there!), I'll play.

I say around :46-:47 in.

[RetroRuss]

I thought around 31 seconds....but then again I have used and abused my ears over the years!!

[Videoskooter]

Originally Posted by RetroRuss

I thought around 31 seconds....but then again I have used and abused my ears over the years!!

Then we are both "old" coz I'm hearing the same thing at about 31-32 seconds. To my wrecked ears it's like a booster that is starting there.

But then again, I'm not a sound engineer.

[Videoskooter]

Originally Posted by Dayna

Orders large popcorn and diet Dr Pepper.............

Off-topic but...after all these years I still don't get what Americans like about Popcorn (I've eaten it once in my life and my stomach started a revolution for 2 days) and then, OMG Dayna, Dr. Pepper, you can hardly get that over here but I did, also once and...after 1 zip I threw the bottle into the garbage bin

But I still loves ya, ya know

[QUINNY]

Thanks to all for taking the test so far.

I'll keep it going for another day and post the info concerning the audio then.

RobbaDobba: Who mentioned welcoming anybody with open arms?
Actually, I thought Ben took it all in good humour, mirroring the manner in which the banter was given.

[Mixmachine]

Listening thru my Sennheisers 580 head set distortion on the low ends begins at the 30/31 sec mark and gets worse after that.

But I had to listen to the clip many times and isolate (in my head) all the instruments one by one to catch the changes.

I'd also like to know what you did to distort the sound, I can always tell a good over all recording from a bad one, but i don't necessarily know how to identified what was done to a recording (on CD pressings) during mastering in the studio to make it sound 'muddy' like your sample does. (i.e. Compression, clipping, limiting, etc).

[QUINNY]

Thanks to those of you who took part in this evaluation. To the other 260 odd who read it and didn't bother.......*&$$#+#!!!!!!!!!!!

It's interesting to note that clipping started @ approximately 16 seconds with peaks hitting +0.6dB over digital zero, at that point.
At 30 seconds there was a change up (I increased level by 0.6/0.7 dB at 6 second intervals, starting at 12 seconds) to the point where peaks were hitting +2.5 dB. This may or may not have any significance, but it is eerie to note that the average human being perceives 3 dB as a significant change in level (although some claim they can hear the difference of 1 dB or less), so it could be (and I have to stress, could be) that at this level it was the perceived change in volume that lead people to assume clipping was the cause and the fact that the change up coincided with a fierce bass synth note, making it more obvious. By the end of the sample (54 seconds +), levels were peaking just under + 5dB over digital zero.

So, of those who took part, only one persion noticed anything prior to + 2.5 dB clipping and no one picked up on the first low levels clipping.

Below is a sentence that parphrases what all the books on the subject tend to say.

" Digital audio is totally unforgiving in this respect. Once your volume level hits 0 you experience what is called 'digital clipping' (square wave clipping). A warm and fuzzy sound it's not. You must keep the very loudest part of your audio (spikes) below 0 dBs."

Although not by any means conclusive, I 'll leave you all to your own judgements about ALL digital clipping being so obviously noticeable and bad. Best practice will always be to avoid going into the red, but for the odd peak, I stick by my guns that in the real world, you can get away with it.