What causes an emphasis on 'cha' and 'sss' vocalizations?

Wseaton

Member
2005-08-12 4:44 am
Greetings all,

Was at a co-workers today for a BBQ, and he took take me for test spin with his prized home theater. Forgive me if I didn't get the name of his main speaker brand, but they were quite large, and featured a ribbon tweeter along with dome midrange and MTM arrangement with what I thought were kevlar mids being they were the typical yellow cloth texture. They we're not DIY but an american brand I'd never heard before. Trust me, one thing they weren't were Chinese knock-offs because the wood working was WAY too good and what he paid too ridiculous.

Anyways, while they had incredible detail and dynamics, I noticed that everytime a singer hit a 'cha' or 'sssssss', or similiar mouth vocalization, it was like the speaker over emphasized the response by several dB, and it grated on my skin. Heard this with several recordings, so it wasn't that particular source. My co-worker friend was oblivious to the problem, although in all honestly it was obvious my ears were more sensitive to playback defects than his.

The reason I'm posting this is I've heard this similiar problem before in speakers ranging from $1000, to $10,000, but it always seems more pronounced with bigger, more complicated driver alignments.

Is what I'm hearing caused by a particular crossover defect, or just a driver design in general? I figure our DIY veterans have perhaps caused this characteristic on purpose or not on purpose and can shed some light.
 
Pronounced 'ss', 'sh', 'ch' is known as sibilance and can be caused by any component in the audio chain. Sometimes the recordings themselves may be flawed by too bright a sound and excessive highs. It is pretty difficult to immediately pinpoint the cause in a complete system; however, cure can begin with better power chords, interconnects, speaker cable and then moving on to the electronics and finally speakers (since you say they are branded and highly priced, they should not be inherently so flawed).
 
Sibilance is caused by narrow peaks in the high frequency region. If you can do an in-room measurment start there. I'd look at the speakers before I'd start switching power cords. Before you even measure try listening with only one speaker playing at a time. If one of the tweeters or ribbons are broken it will be obvious which one.
 

CLS

Member
2005-06-17 6:58 am
Taiwan
jdybnis said:
... I'd look at the speakers before I'd start switching power cords. ...

Absolutely!

My experiences on power cords/wires/ even resistors/capcitors are relitively "minor" in such illness. They might be somewhat effective from "pretty good" to "perfect", but not on such case.

If the basic ain't right, peripherial can not give any helps.
 

soongsc

Member
2005-03-26 2:31 pm
Taiwan
Maybe they were intentinally designed like that to make them sound different from accurate speakers? Some speakers in intentionally designed to produce feeling of a large sound stage, some are desigened with enhanced highs. Each could be designed to target specific customer tastes.
 

speaker

Member
2004-03-23 9:44 pm
USA
Wseaton said:
I noticed that everytime a singer hit a 'cha' or 'sssssss', or similiar mouth vocalization, it was like the speaker over emphasized the response by several dB,

I'd love to see the frequency plot for them. Could be a laid back midrange making the HF seem over-emphasized. Could be an amplifier clipping on the dynamic transients. Could be any of the things previously mentioned too.

I'd also pay heed to soonqsc, they could just be designed to sound like that. To an older customer with damaged hearing, they might sound more natural than speakers with a neutral tonal balance.

speaker
 
I know the sound that you're referring to, and I've narrowed it down to a couple problems in the past. Metal dome drivers are notoriously "spitty" when they haven't been properly crossed over, or have a big resonant peak. I've heard that some of the stiffer coned mid drivers can also do this to some extent, but I haven't experienced that first hand. HF distortion in the electronics chain, whether it be amplifiers, preamps, or source can also do it. A poorly setup cartridge can make your ears bleed like this. Another thing to look at is connections. Not the cable, but the connections. I've had a bad connection cause this type of distortion. It could also be that your friend has very revealing speakers and a brittle sounding amp, or that the equipment all errs toward the bright side, and the resulting sound is nasty and bright. So many possibilities.
 

soongsc

Member
2005-03-26 2:31 pm
Taiwan
Re: Re: What causes an emphasis on 'cha' and 'sss' vocalizations?

speaker said:


I'd love to see the frequency plot for them. Could be a laid back midrange making the HF seem over-emphasized. Could be an amplifier clipping on the dynamic transients. Could be any of the things previously mentioned too.

I'd also pay heed to soonqsc, they could just be designed to sound like that. To an older customer with damaged hearing, they might sound more natural than speakers with a neutral tonal balance.

speaker

Age is a good point. Elder people are financially more capable of buying higer priced products, so a system is designed for them to remember music back in the good days really makes sense.:) Makes me really want to go and get a hearing inspection.
 

Wseaton

Member
2005-08-12 4:44 am
Your description sounds to me like underdamped cone resonances in teh kevlar cone. Would this manufacturer happen to be using large kevlar woofers crossed to that dome? or be big on 'minimalist' crossovers

Bingo.

Looked like he was running 7" kevs or similiar in MTM, and they looked a lot like Eton. I wish I could recall the speaker name.....Legion or something.

What's more interesting is it shows how different we are in terms of perception of sound, although honestly even though the system was super smooth otherwise, the 'sibiliance' problem (to my ears) was more irritating than any thing a Bose cone could come up with. I've heard similiar anomolies with certain metal domes, and this was worse consdering there were no metal domes in the system.
 

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Ron E

Member
2002-06-27 10:41 pm
USA, MN
Sibilance is often caused by emphasis in the 6-7kHz region. It can also be caused by room effects and also by a sudden broadening of directivity - which causes a spike in power response rather than on axis frequency response.

All this talk of power cords and amplifiers is mostly nonsense.
 

Wseaton

Member
2005-08-12 4:44 am
That's the speaker, although his dome tweeter looks different.

It can also be caused by room effects and also by a sudden broadening of directivity - which causes a spike in power response rather than on axis frequency response.

But....wouldn't that show up on a simple response measurement as a spike at 6-7k? Or, is the sudden radiation over a larger area just not picked up by well by typical measurement equipment, but more obvious to our ears.

IMHO - anybody who blames this problem on power cords, interconnects and amplifiers makes we wish for an ignore switch.
 
re sibilance

This effect is almost always due to tweeter resonances. The earlier dome tweeters with mylar diaphrams such as Philips dome tweeters of the 70's had a sibilance peak, the foam block inside the dome was an attempt to damp it, many cone tweeters of the time also had it and this was in most cases a showroom bump to increase the subjective"brightness".
I suspect that in the case of the ribbon or planar type of tweeter a vertical resonance is the most likely culpret.
 
Ron E said:
Sibilance is often caused by emphasis in the 6-7kHz region. It can also be caused by room effects and also by a sudden broadening of directivity - which causes a spike in power response rather than on axis frequency response.

All this talk of power cords and amplifiers is mostly nonsense.

This is pretty much exactly the way I feel about it.

Normally it's either a poorly designed/implimented driver or crossover. I can't stand an overally siblant speaker- This coloration hits the top of my irratation list. More speakers have problems here then don't, and higher cost $$ drivers or expensive cables really doesn't make them any better. Smooth high frequency response is really something that can be improved with a decent measuring system, a handful of parts, listening and patience provided the treble is somewhat resonant free to begin with.

:whazzat:
 
Ron E said:

All this talk of power cords and amplifiers is mostly nonsense.

About the power cords, i have same opinion, about the amp, NO !
I have built/designed many amps now, this "sss" seems to be a typical
solidstate-amp weakness and can be avoided.
It can be caused by combined effects from the amp and the speakers,
but with correct amp this always go away.
A lot of commercial amps show this symptom...

You can hit me if these speakers were connected to tube-amp...

Mike