Ear Directly Next to Tweeter Sounds Weird

[ksulliva01]

Recently built a pair of DIY bookshelves. Upon completion, the instructions say to (very quietly) listen to each individual driver with your ear right up against it to ensure that the connections, crossover etc. are working. When I put my ear right up against the tweeter I notice what sounds like slight but continuous distortion that coincides with and reacts to music, hard to describe, very high frequency, almost a slight hissing, flapping distortion that seems to be related to relative HF content and volume, and overlays all audio reproduced by the tweeter. Easiest to hear on solo piano, things like that. This is not the constant tweeter hiss often found in active monitors and some amps or a noise floor, it rides along with and is dependent on the audio being played.

Thinking the tweeter may have an issue, I hooked up a different speaker (Elac DBR62) and up close, its the same effect, so I'm assuming this is just a characteristic of sticking your ear right next to a tweeter. This effect is not audible once you are more than a foot or so away, so it's irrelevant out in the room.

Just got me curious though, what is this? Is it just super high frequency content that is easily audible with your ear that close, but get's drowned out in the room by other frequencies, reflections etc.? Is it actually a distortion characteristic of tweeters that can only be heard in the extreme near-field?

 

[DVDdoug]

Well... The louder the sound (including on how close you are to the speaker) the louder the little details, noise, and distortion get. At very-low levels it's hard to hear these defects (or details). They don't always sound worse when louder because the little defects are often masked (drowned-out) but with your ear to the tweeter the lower frequencies are less-likely to drown-out the higher frequency defects.

hard to describe, very high frequency, almost a slight hissing, flapping distortion that seems to be related to relative HF content and volume, and overlays all audio reproduced by the tweeter.

I'm not saying this is what you are hearing, but that's basically what quantization noise sounds like. It's a noise or "fuzz" that rides on top of the signal. Like regular analog noise, it's most noticeable with quiet sounds and it tends to be masked with louder sounds, but unlike analog noise it goes-away completely with pure digital silence. (I've only actually heard quantization noise with 8-bit files.)

 

[ksulliva01]

that's basically what quantization noise sounds like

I know that quantization sound, it's somewhat akin, but this was a 16bit file. I guess its just very low-level distortion that's audible up-close on highs. Going to try some different amps to rule that out, although the amp I'm using measures very low distortion.