Speakers passed test, but this sound comes out...

[CatLady221]

I have a Macbook Pro which I've used the speaker test on and it passed. However, when I play my sub (LGOPR) using the ultrasonic format there's a slight crackling sound. At 50% volume the crackling is there but it is just about unnoticeable. Here's a recording of it at 50% volume, I recorded this on my iPhone and it does sound louder than it actually is but that is the crackling noise. Is that normal?

Sound recording link:
http://s000.tinyupload.com/?file_id=6662...8241558296

[Breeze]

It doesn't sound normal to me. Is it still there if you play the sub at, let's say, 30% or less? Also, you can download a free sub and compare the crackling sound to verify if the LGOPR isn't corrupted.

[CatLady221]

It doesn't sound normal to me. Is it still there if you play the sub at, let's say, 30% or less? Also, you can download a free sub and compare the crackling sound to verify if the LGOPR isn't corrupted.

Ok, so at 30%.... it's still there but only if you're real close to the speaker, like ear right above it close. At around 25% volume, there's no more of that weird crackling. I've also used the ASC and EPRHA subs and yes the same issue occurs at 50% volume.

[Breeze]

I do not have a Macbook Pro, so maybe others can chime in. Though, to be on the safe side, I'd recommend listening to your subs at 25% or the maximum volume at which there is no crackling sound. I, myself, play ultrasonic subs from 15% to 25%.

[apollolux]

I have a MacBook Air, almost certainly the same speaker tech inside. Playing ultrasonic from it indeed needs output volume at a sweet spot between 25% and 40%; basically, max out your player's volume (probably iTunes or QuickTime Player) with no EQ enabled and set your system volume as close to 30% as you feel comfortable with (I have mine set to as close to 42-45% as is possible without visible numbers). If you have a means of testing output volume (apparently Frequensee Pro can do it, but the free version can't) follow what CatMan recommends in other threads.

@LeonidasXVI - she says in the OP that she has the free speaker test and used it to initially calibrate.