crossover for seas 27TFFC

[zega55]

Hi can any one help me and recomend a type of crossover for this tweeter I am crossing it now at 3khz with 12db/oct but I hear some times sssss and I dont like it. Can I use a 18db on tweeter and 12db on midbase . Any help is great.
Or attenuate it ....

Ivan

[Zaph]

The chances are nearly 100% that the sibilance is coming from the woofer, likely in the form of breakup induced harmonic distortion, if not a poorly controlled response curve. That is the number one tweeter misdiagnosis.

[zega55]

thank you I will disconect the tweeter and hear the midbase and see if it is the problem and hear the tweeter alone with the crossover , how can I fix that problem . I can show you the curve for the midbase and the T/S parameters here

http://www.dobar-zvuk.hr/hi-fi/8home/home_hw_6al.htm

thank you for the post

[Dave Bullet]

Without having even seen the driver / response in question, Zaph has given you a pretty good idea.

Since the woofer's peak is between 4-5KHz, and it is 5+dB - a steeper crossover probably won't be enough at a 3KHz crossover point.

A series notch filter might be what you are after. This is an inductor, capacity and resistor in series, that are then wired parallel to the woofer. www.lalena.com provides some textbook formulas that might get you in the ballpark. However, this could be hit and miss (dependent on the resistance the circuit will see at the frequency - which is not the same as the driver resistance at that frequency). You will probably also change the phase response through the crossover region by adding a LCR filter. So although you might get a flatter frequency response, it may help (or make worse) the phase response.

David.

[sreten]

Hi,

If that is an aluminium coned driver, without knowing the writing
speed of the frequency response curve tracer, you do not know
how much smoothing is applied to the response curve.

But for some information see here :

http://www.zaphaudio.com/audio-speaker12.html

And here :

http://www.zaphaudio.com/audio-speaker17.html

Also see here :

http://www.rjbaudio.com/Audiofiles/FRDtools.html

/sreten.

[zega55]

I have a RLC parallel notch filter on the woofer it is calculated to compensate for that bump and the sibilance is not coming from the woofer because I disconnected the tweeter and heard it then and attenuate the tweeter 3db. The sibilance did not came from the woofer.The woofer has a Zobel

the sibilance is now almoust gone.I dont have any equipment to measure the woofer SPL in the box .

You ware of great help guys , sorry for my english

[sreten]

Hi,

Possibly baffle step compensation and attenuating the tweeter by
the amount of baffle step compensation you use (assuming it is
already level matched to the bass/mid) will cure your problem.

4dB to 5dB of baffle step is the most common amount used.

/sreten.

[zega55]

Yeah I will try it Sreten it can help do you think I should make a new crossover for all and make a smaller attenuationon the tweeter ?

[sreten]

Originally posted by zega55
Yeah I will try it Sreten it can help do you think I should make a new crossover for all and make a smaller attenuationon the tweeter ?

Hi,

if no baffle step compensation - you need it and larger tweeter attenuation.

/sreten.

[zega55]

Do you have an idea for the crossover and attenuation Sreten can you help please