About changing crossover frequency of a speaker

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gaetan8888

Member
2007-04-08 5:11 pm
Hello

I have a homemade bass reflex loudspeaker using Dynaudio 17W75 woofer and D28 tweeter, there is a passive 6db crossover and I will change it for a passive bessel 12db crossover.

I can put the center frequency of that crossover at 2000 hz but I was think to go lower at 1600 hz, so less high would goes into the woofer and also because the tweeter do have an excellent transient response and also because the soundstage are mostly in the high frequency harmonics so the tweeter will do that job best.

Is it a good ideas, any suggestions ?

Btw, I will also ad a Zobel network, and both the tweeter and the woofer can run at 150 watts, and my amp are 60 watts.

Thank

Bye

Gaetan

(Here is the frequency response graph of the Dynaudio woofer and the tweeter.)

An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.
 
Hi

Lowering the crossover point is mainly a question of tweeter distortion in its lower range (increased excursion).

In your case, the tweeter appears to have an Fs around 1000 Hz. If you go too close to the resonant frequency, the tweeter begins to distort - how and how much cannot be told without a distortion measurement.

A 12dB crossover at 1600 Hz would probably too low, you would end up with distorsionat higher volume levels. I would either stick to 2kHz or use higher order filters (elliptic would probably work, but not trivial to design).
 

Thawach

Member
2007-12-13 9:48 pm
bzfcocon i agree with you.
And i had ever done it before. It's not good. At the midrang frequency about 1500-2000 hz that sound is hard. I can't get both of them.(image and soundstage) because i hear the sound that have hamonics+distortion.

Thank you
Thawach
 

Thawach

Member
2007-12-13 9:48 pm
Hi! gaetan8888
If Dynaudio D28 tweeter have a FS of 880. I ever saw magnet loudspeaker. They use morel tweeter and set cut-off at 2200 hz
The morel tweeter have fs at 750 hz. Please see the circuit below.

http://www.magnetaudio.com/store/en/shop.asp

Thank:
Thawach
 

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gaetan8888

Member
2007-04-08 5:11 pm
Hello

Here is the crossover I would use.

Here's the formula;

L = R/pi*frequence

C = 1/(4*pi*R)*frequency

R are the speaker impedance

L are in Henry

C are in Farad

But the formula seem to be wrong since it not give right values ?

Anyone did try that type of crossover.

Thank

Bye

Gaetan
 

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Thawach

Member
2007-12-13 9:48 pm
Gaetan

I forget to tell you. I ever saw mirage book shelf speaker. Crossover at 1700 hz. The crossover of it has a zobel and notch
filter for tweeter. I think that crossover order 1+ zobel for woffer. About the crossover calculator that you use it for only
reference. you fine tune it by listen again. Everytime you change box volume . you must fine tune it again.

Thawach


-----------------------


Your helps are the best of you.
 
Hello

The orginal crossover are very simple, a 6db crossover with a 2000hz center frequency and a Zobel.

I will made a Bessel 12db

My original ideas was to made a bessel active crossover with bi-amp but it's using to much op-amp, so I did get back to passive one.

Thank

Bye

Gaétan
 
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