[Niouke]

Hello science crowd,
Is there any science and/or any mesurable data behind sibilance? Or is it just the brain/hear that can't follow what you are listening to? I have reportedly sibilant IEM's, xba-300's, but I've never been able to experience sibilance, If I can't hear the trebles precisely I just turn the volume down...

Thank you all for the good reads I've been learning a lot reading the threads around here.

 

[ProtegeManiac]

Hello science crowd,
Is there any science and/or any mesurable data behind sibilance? Or is it just the brain/hear that can't follow what you are listening to? I have reportedly sibilant IEM's, xba-300's, but I've never been able to experience sibilance, If I can't hear the trebles precisely I just turn the volume down...

Thank you all for the good reads I've been learning a lot reading the threads around here.

There is and it depends on a lot of factors.

1. Non-linear response on the system. That can be headphones, or the in-room response of the speakers. For the most part, on headphones this is most normally due to a headphone or IEM that has a treble peak. In some cases it's due to that peak further exacerbated by how a headphone fires directly into the ear canal, while some like the HD800 have the drivers angled off-axis, mimicking the toe-in on speakers. Quantitative data here is easy - response will show a peak somewhere between 2500hz and 10000hz.

2. Time alignment issues - you hear the tweeters' output out of sync with the midwoofers. Sit too close to speakers, and whatever is already bouncing off the walls will add to this (ie you hear the tweeters' output out of sync with the midwoofers, plus the reflections). This is even more severe in a car since you don't have a system in a Mclaren F1, so instead of just tweeters vs midwoofers, you have driver's side tweeter vs driver's side midwoofer vs passenger side tweeter vs passenger side midwoofer, plus the tweeters bouncing off the windshield and the midwoofers bouncing off everything that's leather and plastic. Quantitative data here is easy - take a tape measure and see how far each of these is from your nose for easier reference. On home systems usually you just sit farther back or angle them; in cars, you do custom installs to do proper toe-in with toe-up angles, plus you use a Time Alignment DSP to delay the closer speakers and sync them with the farthest one (typically the subwoofer). On a properly installed and tuned (the DSP will only really work if you have active crossovers in the DSP to split the signal, giving it an individual signal for each driver to delay as tuned) car audio system, like those you can find in an IASCA or EMMA event, the vocals will be dead center on the dash and at eye level height, everything spread out around it, and the bass notes are seemingly coming from the dash rather than the boot.

3. Your own ears' non-linear response. Some people have hyperacusis, exacerbating the perception of treble. Some have hearing loss and feel that strong treble is just about normal.

 

[Niouke]

OK thanks that answers a lot of questions. The term "sibilance" is, as suspected, a blanket term that regroups any treble perceived as abnormal.

 

[bigshot]

Distortion in narrow upper frequency ranges and frequency response imbalances are the most common reason for sibilance. Sometimes it's baked in to the vocal tracks because of bad engineering (lousy microphone preamps or over driving vocals combined with lots of vocal compression).

 

[gregorio]

OK thanks that answers a lot of questions. The term "sibilance" is, as suspected, a blanket term that regroups any treble perceived as abnormal.

Technically, "sibilance" is a term applied specifically to the human voice (speaking or singing) and is most common when pronouncing words containing the letter "S" (although it occurs with some other consonants too). Some amount of sibilance is desirable of course and it's only a problem when there's too much of it, which is a common result of a close, on-axis microphone placement and some people's voices are more prone to too much sibilance than others. In fact, too much sibilance ("essing") is one of the most common of all recording faults, so there are quite a number of de-essers on the market and pretty much without exception every pro sound engineer has at least one (I have 5 and use them routinely)! However, applying de-essing has undesirable, unavoidable consequences, so the general rule is to apply as little as we can get away with. In the case of IEMs or other reproduction equipment which significantly over-hypes (boosts) the frequency range where sibilance lives, it's entirely possible the amount of de-essing applied is insufficient.

It's possible that audiophiles have misappropriated the term and use it for anything with an over-hyped mid-high freq range, rather than specifically for speech/singing.

You most certainly have experienced sibilance, as it's an integral part of every language I know, although it's entirely possible you haven't experienced unnatural/uncomfortable amounts of sibilance. The most obvious reason for this is simply that you don't listen to recordings which contains any! If the recordings you listen to don't contain a considerable amount of mid-high content, then your IEMs boosting that frequency range would just result in a higher mid-high balance than intended but not to the point of uncomfortable over-sibilance (essing).

G

 

[Niouke]

OK then, having toyed with microphones I did experience sibilance, but I didn't know there were specialized de-essing equipment. Now I gotta look for recordings that exhibit such characteristics! Thanks for the info.

 

[gregorio]

[1] OK then, having toyed with microphones I did experience sibilance, [2] but I didn't know there were specialized de-essing equipment.

1. You do experience it regularly, you'd have difficulty communicating if you didn't. For example, the difference in pronunciation between "hurt" and "hertz" is the sibilance at the end of "hertz", if you couldn't experience sibilance then you wouldn't be able to differentiate these two words. You don't need a mic to experience even over-sibilance (essing), just put your ear fairly close to someone's mouth and get then to speak a sentence which includes, for example, the word "sip". You'll be surprised how loud the sibilance is that actually exits the mouth (which is why a close mic captures it), careful though, the SPL of sibilance very close to the mouth can be painfully high, even if the speaker isn't speaking particularly loudly.

2. Yep, there's loads of them. Most are essentially band limited compressors and so a multi-band compressor can be used for de-essing but many of them are a little more sophisticated, for example some have a detection threshold which enables them to at least partially adjust bandwidth and centre point of compression automatically. The danger is always that you're not compressing/reducing only the sibilance but everything in that frequency band and that band is fairly wide. De-essing is therefore often somewhat of a compromise, particularly when dealing with quite severe essing. Often you have to settle for reducing the sibilance less than you'd ideally like and leave some essing (over-sibilance), because reducing the other sound components in that frequency band by the amount ideal for the sibilance would give an even poorer overall end result. It's a judgement call but in this case (which is not uncommon) a system which boosts that freq range is going to easily take the sibilance over the border and into the uncomfortable/unacceptable range.

G

 

[PETEBULL]

Practically there are two kinds of sibilance:
1) s-s-s-s-s-s-s-s
2) sh-sh-sh-sh-sh
The first one is natural, the second one is irritating and dirty. If there is one, it better be as high in frequency as possible.
But some audiophiles think of low freq sibilance as an advantage.

 

[bigshot]

You left out one....3) tttthhhhhhppppPPPPPPPPPPP!