dynaudio crossover - value of tweeter resistor?

[adamt]

Hi Friends.

Just playing around with my crossover, as I am occasioned to do.

At the dynaudio diy archive : http://www.gattiweb.com/dynaudio.html
the crossover for the Dynaudio Nuance speaker with a D260 tweeter has a 10 ohm resistor in series with the capacitor.

For other designs on the same website using the same driver and tweeter, the value listed is between 1.1 and 2.4 depending on the 'sound' you prefer.

At other websites, the same Nuance design lists the tweeter series resistor as 2.2ohm.

They cant all be correct! So i tried it out...

At 10 ohms, the music is a little recessed for my taste.
At 2.2 ohms it can get a bit bright on some recordings.

I am worried that by choosing my own value, I might ruin the L pad design.

Does anyone have any ideas?

[infinia]

Hi
Dynaudio Nuance Schematic from the site you linked. The only values shown adjusting for different tweeters.

C6 = 1.0 uF & R3 = 6R8 for D260 tweet
C6 = 1.5uF & R3 =10R0 for others

This series RC circuit is a zobel to keep the tweets Zin flat at higher frequencies. so tweeter Zin is approx = R3 at all frequencies higher than Fs.

How about the other site/s you mentioned?

My suggestion is, just use dynaudio values for R3. If the tweeter levels need adjusting for taste try R1 in the pad formed by R1, R2, and tweeter impedance Zin.

Vo = Vin*(R2//Zin)/(R1+(R2//Zin))

atten = Vo/Vin = 20*LOG(R2//Zin)/(R1+(R2//Zin)) where Zin = R3

hope this helps

[adamt]

Thanks Infinia

R1 is the resistor in question - sorry if I did not make this clear.

And on other website
http://www.geocities.com/CapeCanaver...91/nuance.html
it recommends a resistor between 1.8 and 2.2 for the same Nuance design(in the diagram it is labelled R2 which is the same as R1 in the original link)

I have tried the recommended 10ohms and found the sound a little flat.

I have also tried a resistor of 2.4 ohm and found the sound a little bright!

My question is, if I choose a resistor that I think sounds right (it could be 5.6 ohms for example), will this ruin the lpad, or any other part of the crossover (impedence etc)?

thanks again

[infinia]

R1's change in value will not alter the crossover frequencies as changes to R2 and R3 will have an effect to some extent.