What technical issue ruins sibilants?

AllenB

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Paid Member
2008-10-18 11:31 am
I'm referring to that sound where a singers tongue seems to bounce, sounding like it is spittle covered at the time (sorry for the image :eek:)

I've narrowed it down to four possibilities that I can think of (these are only suggestions)

1. It's just there in the recordings (as I certainly don't notice any on some recordings)

2. A group delay between woofer and tweeter.

3. Power response irregularities around the crossover with flat on axis response.

4. Frequency response irregularities around the crossover.
 
I went full range driver specifically because of this sibilance issue. There must be other ways of minimizing it even in multi-way systems. If the response has a rise around 2 - 4 kHz there is sibilance. Probably also related to crossover issues for sure in many cases. The tweeter isn't always to blame, it can be the woofer/midrange driver breaking up around those frequencies. Sometimes it's on the recording. Once you minimize it it's easy to spot it on other speakers/sound systems. When it's gone or minimized you don't miss it!
 
Hi,

Poor distortion performance from any part of the chain can ruin sibilants.
Sometimes this can even be on the recordings, treble peaks don't help.

So called "Exciters" used on pop recordings can be a cause of sibilance.

Basically its either distortion or treble peaking accentuating the harmonics.

rgds, sreten.

There are also the much rarer self descriptive terms shibilant and thibilant.
 
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AllenB

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Paid Member
2008-10-18 11:31 am
Bad crossovers can add it to an otherwise good recording.

The biggest variable in my system is the recordings. They're just all over the place, so I'm thinking the recording chain is mostly to blame. My 3-4k region is down 2dB.

However, I don't expect every recording to trigger a specific fault in my system, so I'm still suspicious, but I do believe that the problems I hear on some recordings seem greater than any problem I'm able to clearly identify in my system.

So how would I confirm a bad crossover? My on axis response is +-2dB over the central regions (with 1/3 octave smoothing) with the right trends about it. Off axis has recieved attention. Would I find it in the phase data? My drivers are not time aligned by any means but they add well all the same.
 

Pano

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2004-10-07 6:05 am
Panama
Phase can do it, or as sreten mentions, distortion. Those harmonics don't show up on the FR plot, but you can sure hear them. So it could be distortion on the low end of the tweeter's range, and maybe phase issues. It isn't easy to solve.

Do you have a good pair of headphones to compare to?
 

AllenB

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Paid Member
2008-10-18 11:31 am
With regards to distortion, I'm using good compression tweeters at domestic levels. They are also crossed well below the normal sibilance region.

My system bears quite a resemblance to my headphones ($100, made using FEA, not too bad) mainly in the areas of timbreal balance and the dry acoustic.

My biggest technical concern about my system is that the tweeter is over six inches behind the woofer.

Currently about a quarter of all recordings on my system sound better than I have ever heard them anywhere before (BTW, thanks to knowledge gained at this forum), and I could probably double that if I would loosen up to a nice EQ...I've heard many a bad recording sound much better on a system that by its character gives away the fact that it is thoroughly EQed. Per song settings would be even better.

One thing that I have found by my incorrectly using so many dome tweeters in the past (as opposed to using dome tweeters correctly) is that when you stress their low end, and you mis-match the power responses of the drivers you get a certain character that highlights the crossover in a bad way and you can always hear it. The recordings that sound good on these systems don't hide the fault so much as they exploit it, which is really just a coincidental thing.
 
With regards to distortion, I'm using good compression tweeters at domestic levels. They are also crossed well below the normal sibilance region.

...... is that when you stress their low end, and you mis-match the power responses of the drivers you get a certain character that highlights the crossover in a bad way and you can always hear it.

If the crossover is too near the tweeter's impedance peak, it can cause the tweeter to resonate. First order on tweeter is also prone to this.

Mike
 
IME sibilance is mostly on the recording, that is to say some vocalists are more prone to it than others and female more than male voices.
The impression of excess sibilance can be due to the drummer being to keen on using his cymbals. A friend of mines band had a female singer slightly prone to it but it almost completely disappeared when we faded out the drums.
With male voices it is fairly easy to eq it out but female voices can not be easily eq'd because there is not much to them ie no lows and no highs and any eq tends to change the characteristics. Cut the lows and it becomes nasal, cut treble and it becomes dull.
This also makes female vocals very difficult to record in the first place but it also means that a good recording of a female voice is an excellent way of testing a speakers mid range quality. Male vox have a lot more content above 3-5k than female vox.
Mic choice and placement are of utmost importance for female voices.
 

AllenB

Moderator
Paid Member
2008-10-18 11:31 am
First order electrical, and I do run it slightly below its "recommended" frequency, if resonance could be considered as significant in a compression driver. I have the peaks covered. Three notch filters, one damps the resonance electrical peak, one reduces an acoustic peak, and one is at 3-4k (for obvious reasons :D) and cuts a couple of dB, plus there is some padding.

The tweeter is rated at 60W and I can reach neighbour disturbing levels with just one Watt covering that half of the spectrum (this includes the power wasted in the crossover over the active region, which is probably around half).

BTW, I'm glad (in a sense) to hear that there is such an issue with recordings.
 
Hi,

First order on a compression driver ? That is just begging for trouble.

Harmonic distortion might be the usual way of looking at things but
in reality its the very related intermodulation distortion that is the
real killer, horn loaded drivers don't like lower frequencies at all.

They are typically rolled off 3rd order* above the frequency the
horn unloads the diaphragm, there is no point whatsoever trying
to explore the lower frequency capabilities, its very pointless.

rgds, sreten.

*usually assumed this is above driver resonance, horn cutoff
is higher than than that and a sensible point is again higher.
 
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