Histoires de filtres...

[jerome69]

Decrease R (current increases about 2x):

[jerome69]

Only a few designers are aware that electrical resonances in crossover circuit should be dampened. The acoustic slope remains roughly the same in all cases above, hence a first-ordered electrical filter is NOT equal to a first-order acoustic slope!

I don't know the exact reason why the first-ordered circuit is the only one that is non-sibilant. My suspicion is a combination of less electrical resonance, more transport of charge (current flow), and the fact that a unit is not exactly a Thiel-Small parameter equivalent when used dynamically.

Marc


Thanks again for this fine analysis on electrical filter circuit. Hope this helps to design very high end loudspeakers.

[Brunoch]

Bonjour à tous ,

J'en profite pour mettre mon lien car j'ai besoin de conseils pour le filtre de mes enceintes.
http://www.cinetson.org/phpBB3/post403986.html#p403986

Merci d'avance pour vos conseils.

[crazyhub]

Only a few designers are aware that electrical resonances in crossover circuit should be dampened. The acoustic slope remains roughly the same in all cases above, hence a first-ordered electrical filter is NOT equal to a first-order acoustic slope!

I don't know the exact reason why the first-ordered circuit is the only one that is non-sibilant. My suspicion is a combination of less electrical resonance, more transport of charge (current flow), and the fact that a unit is not exactly a Thiel-Small parameter equivalent when used dynamically.

Marc


Thanks again for this fine analysis on electrical filter circuit. Hope this helps to design very high end loudspeakers.

Merci à Jérôme, ainsi qu'à Marc Heijligers
La "sibilance" càd "sifflement" que je "traduis" à l'écoute par des "SSSS" ou des "SSSCH" trop prononcés en attaque de notes ou de voix (c'est bien ça?) ne devrait-elle pas se voir sur une courbe d'intensité fréquentielle (niveau spl plus élevé sur une ou plusieurs fréquences et/ou niveau relatif différent entre bandes de fréquences différentes) ET/OU sur une courbe de distortions?
Les résonances de circuits électriques expliqueraient-elles, au moins pour partie, les différences de comportement (et donc de sonorité) entre différents amplis ?

[jerome69]

Only a few designers are aware that electrical resonances in crossover circuit should be dampened. The acoustic slope remains roughly the same in all cases above, hence a first-ordered electrical filter is NOT equal to a first-order acoustic slope!

I don't know the exact reason why the first-ordered circuit is the only one that is non-sibilant. My suspicion is a combination of less electrical resonance, more transport of charge (current flow), and the fact that a unit is not exactly a Thiel-Small parameter equivalent when used dynamically.

Marc


Thanks again for this fine analysis on electrical filter circuit. Hope this helps to design very high end loudspeakers.

Merci à Jérôme, ainsi qu'à Marc Heijligers
La "sibilance" càd "sifflement" que je "traduis" à l'écoute par des "SSSS" ou des "SSSCH" trop prononcés en attaque de notes ou de voix (c'est bien ça?) ne devrait-elle pas se voir sur une courbe d'intensité fréquentielle (niveau spl plus élevé sur une ou plusieurs fréquences et/ou niveau relatif différent entre bandes de fréquences différentes) ET/OU sur une courbe de distortions?
Les résonances de circuits électriques expliqueraient-elles, au moins pour partie, les différences de comportement (et donc de sonorité) entre différents amplis ?

Exact Crazyhub !
Too many "ssss", "ch" and SPL curve/relative level in SPL curve/distortions.

Sibilance is quite complex. Marc points one of the cause of sibilance.
In my opinion Sibilance is natural in voice, but the problem is when it is excessive, in level and distortion.
Some voice are naturally sibilant (male and female voice) and you cannot do anything.
1.Sibilance is for some people a bump near the 5kHz region
-Some loudspeaker have this bump
-Some professional microphone have some rise above 2kHz like a shure SM58
2. Sibilance is distortion
-Some loudspeaker and microphones have a lot distortion in the treble area.
-The CD source with reading errors, poor sampling (44.1kHz) is very sibilant. These problems disappear with HD records (>96kHz) or Analogue (LP) records.
-Some cable with a lot of fine conductors cause dispersions and distortion in the treble.
-Some amplifiers with poor design make a lot of distortion in the treble.

3. Sibilance is coupling ?
- Coupling source/amplifier/cable/loudspeaker
- Electrical resonance in filter like Marc wrote.
- All these phenomenas

In my opinion these are some reasons for sibilance.

The last question:
Electrical resonance make difference in amplifier behavior, sound ?
Perhaps ? But forme it is not a good amplifier !
A good amplifier should be invariant to its load. It's a very simple assertion but it is a terrible matter which seems difficult to do !

Cheers.

[bernardmail]

Bonjour,

des "SSSS" ou des "SSSCH" trop prononcés

à mon avis, c'est tout simplement la courbe amplitude-fréquence de l'enceinte qui n'est pas ok.

Par exemple, en jouant avec mon DEQ1024 je peux accentuer ou diminuer ce phénomène.

En poussant le phénomène plus loin (en sur-colorant) , non seulemnt on perçoit des "sssss" ou "chchch" mais en plus certains sons de la voix deviennent moint audibles au point de faire commettre des fautes d'élocution ou même de Français.

A+


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[jerome69]

Marc response about sibilance :

---

It is true that a strong ccchhhh (around 4kHz) or sssss (around 8kHz) sound is normal to voices. But this is different from sibilance.

When a speaker suffers from sibilance, the cccchhhh or sssss sound moves to the speakers. Instead of being able to pin-point the direction of for instance a human voice, it seems that these s-sounds are coming from two sides, from both the tweeters. You should be in the middle of the loudspeakers to judge whether you have sibilance, as reflections against the wall play a role here as well (in a stereo setup the s-sound comes from 2 directions, and hence one should have a symmetrical setup to not cause any group delays that affect pin-pointing). Sound that moves to the speakers is a good indicator for any type of resonance in any frequency region.

You can mask sibilance by lowering the level between say 3 and 10kHz, but this is not a solution to the genuine problem. Many recordings are accused of sibilance, but if you take a decent pair of headphones (e.g. Sennheiser HD650), you can hear that most recordings are NOT sibilant, and it is the playback system that has a source of sibilance.

If you have too strong s-sounds, but they are perfectly pin-pointable, you probably don't have sibilance, but just too much treble.

Marc

[bernardmail]

Bonjour Jérôme,

Marc aussi évoque la possibilité de "sss" ou "chchch" en rapport avec l'équalisation.

Mais pas toujours.

A+