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Tech query: Sibilance


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Sibilance is an issue in some loudspeakers, where "S" and "SH" sounds are exagerated, in the region of 6-10 khz. However, some source media ( music ) was originally mastered with a slight amount of sibilance in the original recording.

The amplifier simply takes a small signal and makes it bigger, the loudspeakers are what reproduces the sound.

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On 8/18/2005 1:12:19 AM michael hurd wrote:

Sibilance is an issue in some loudspeakers, where "S" and "SH" sounds are exagerated, in the region of 6-10 khz. However, some source media ( music ) was originally mastered with a slight amount of sibilance in the original recording.

The amplifier simply takes a small signal and makes it bigger, the loudspeakers are what reproduces the sound.

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I'm not arguing, but trying to further explore. If that's the case (and I'm not doubting it), then why do my Khorns sound less sibilant with a tube amp, than solid state? (old Yamaha CR-2040)

Same speaker, different amp.

???

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I think Dr. Who needs to jump in on this one. I say it is usually and mostly caused by the recording, not the amp or the speakers, unless they are very cheap speakers. On the recording side, the sound engineer will take out the excessive S sound with special equipment. So, this shows that it is usually a recording issue. I have ZERO experience with tubes but from what everyone seems to say on these boards, they have a warmer laid back top end that may be perfect for a slightly messed up recording. SS will pass a crummy signal on to the speakers and show a lousy recording as a lousy recording. Dr. Who can probably elaborate on the the great lengths they go to in recording to get rid of that excessive sibilance.

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Tubes TEND to have a slightly sloped rise-time that may serve to slightly round-off the waveform a bit. I've seen it referred to as "full-bodied", "liquidity", or "roundness" in publications trying to describe the "tube sound". I believe that it is this particular quality that provides tube gear with its sonic signature more than anything else (output xformer notwithstanding). Tubes are a high voltage, low current-switching device in the typical configurations, which usually requires an output transformer, and multiple stages of tubes to increase current, respectively. Other considerations are that tube amps sound different because of the way they match to the speaker load and respond differently to variations in load reactance that SS amps do not (to the same degree).

Transistors are a high current, low voltage-switching device and typically are capable of faster rise-times, and therefore have a tendency towards "graininess" or harshness particularily in the higher frequencies if not well controlled. This tendency may be very apparent when the signal being amplified is somewhat shrill in itself, or is restricted to a set of high frequencies such as sibilance, in this case.

In the case of many higher quality amplifiers, the topology employed doesn't matter, UNLESS used to achieve a particular set of parameters, such as "voicing" SS gear for the "tube sound". It should be noted that there are plenty of tube amps that don't "sound" like tube amps in particular (I suppose that it could be apparent with a "trained" listener, but that could be from a combination of things such as soundstage, bass solidity, etc).

There is a trend to create SS voiced to sound like tubes, this is done with alot of SS musical instrument amps.

DM2.gif

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I will phrase it more simply than D-Man:

The output transformers on a tube amp serve as a low pass filter. This explains why the sibilance (probably from a poor recording) is attentuated with a tube amp. This is not menat to argumentative. Some people prefer this sort of sound and will use lots of words like "warmth" and "smoohtness" to describe it.

Good luck,

-Tom

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When conducting comparisons between only 2 amps, you can't pinpoint where the issue lies. A quick test with a pair of quality headphones should suffice in identifying if the source is the problem (aka, listen on a pair of headphones and see if the extra sibilance is still there).

To answer the original question, yes it can be both a speaker or amplifier issue. It can also be an acoustical issue, source material issue, even your current mood/physical state can affect the percieved sibilance. Perhaps the glowing tubes put you in a different more comfortable emotional state?

Considering that the sibilance is heard and not heard with an amplifier change indicates that one of the amps isn't doing its job. Either the source material has sibilance and the SS amp is accurately reproducing it and the tube amp is lacking in the highs, or the source material has no sibilance and the SS amp is adding extra sounds whereas the tube amp is more accurately reproducing the signal.

On a side note, I've always found older yamaha amps to be rather bright/harsh sounding (not so much with the newer ones) so I would have no doubt that your yamaha might be part of the problem. However, I don't think it's fair at this juncture to point fingers at the different amplifier topologies. In other words, extra sibilance is not a problem always inherant with solid state (or tubes for that matter).

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One strange thing that I found with my Primare amp is the fact that the sibilance will vary in the different modes.

With no source connected you will not hear any hiss or at least almost no hiss from the speakers at any volume level, if you are in one of the digital input modes. If you switch to one of the analog modes such as SACD (where the amps DACs are bypassed) the hiss will increase greatly at a certain volume level. I have to say though, that these volume levels would either kill my RF-7s or me.... 9.gif

I figure that this hiss might me produced by induction caused in the interconnects through other electrical wires or high frequency radiaton (cell phones...). This induced signal will then be amped in analog mode.

Nick

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Hi there,

I'm currently playing around with caps and resistors in my pre-amp and believe me these have an effect on the sound of the sssssssssssss's. Use female voices they tend to 'test' your system as to its harshness, brightness and sweetness. I agree that it starts with the recording but ends up through your speakers. You just have to make sure your system doesn't add anything to the recording.

Cheers

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Are you replacing the standard caps and resistors with higher quality parts?

I am really interested in the outcome as I think about doing the same thing to my amp and dvd-player.

I heard that changing the caps in the signal path will make a significant difference in sound quality.

Nick

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Sibilance is NEITHER a result of amp or speakers. It is a real thing that is recorded on many CDs. Some artists have a bad case of it. Wynona Ryder and Sarah Briteman are two examples. Listen to a recording that has sibilance with good quality headphones direct from your CD player and you will hear it! No amp, not speakers and no crossover netwrok. It's still there!

Al k.

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