XSim free crossover designer

[chris661]

Question: Is there a donation page?

My passive speakers have been aided hugely by this software, and since I use them in professional environments (or did, before events were cancelled by the virus), it'd be great to give something back.

Cheers,
Chris

[AllenB]

Originally Posted by dlr

Look at the off-axis. On-axis will probably be worst for a coaxial. A smoother off-axis design point may be warranted. A small degree off-axis may be the best listening position.

Dave

Yes. If the dip is not typical of the wider behaviour, then it's best not corrected otherwise your room will see a peak. Better to go with the acoustic flow and find the axis (to listen to) which is better representative of the bigger picture.

[pawelp]

I checked again and it seems the only way an RLC can boost locally an FR is by reducing the overall efficiency. I attached a simple simulation, if R1 is removed the effect of 9k bump disappears.
It is not about if I finally use this boost in my design I just want to clear my knowledge and what is possible.
Can someone suggest what circuit should be used to achieve a boost in FR without reducing the overall efficiency ?

[wgh52]

Hello Pawel,

NO! Passive networks can only "burn" (parts of) the power fed in by the power amp (that's part of what "passive" means). Passive networks can NOT add power to a signal (an amp does this!), so they will always effectively reduce efficiency! ...more or less...

Hoping this is clear enough,
Winfried

[woody]

I have a speaker that uses a 25uf cap and 4 mh inductor for a full range driver crossed over at 400hz but this crossover assumes the amp has a rather high damping factor. But I may want to use an amp with a 8 ohm output impedance. No I am not talking about the 8 ohm tap on a tube amp but a SIT amp like is talked about on the Pass forum. Is there an easy way to calculate the new values I need without many trial and error substitutions in xsim ?

[AllenB]

woody, here is one method you might use. The first screenshot compares two default drivers, one has 8 ohms added in series and has the component values adjusted to restore the crossover point. In the second screenshot I increased the level of one driver, just to show that they match.

[AllenB]

Originally Posted by wgh52

...more or less...

Yes. Resonance can be used to increase output in some cases. Here I have taken two default (70dB) drivers and increased the output of one by 5dB, over two octaves. More power is drawn from the amp and the impedance is lower.

This kind of approach can also be used to reduce or increase the knee of a low or high pass filter to counter the response of the driver.

[woody]

AllenB , thank you for working that out for me and at the same time showing me how you did it. Really I am surprised that more attention isn't played to how amplifier impedance can affect the crossover behavior.

[AllenB]

You're welcome. It's probably obvious but I wanted to point out that when working on a whole crossover you can put the resistance straight after the amp.

It is important to do this because the parts of the crossover begin to interact. Eg: as the driving signal divides between the woofer circuit and the source impedance, the signal presented to the tweeter circuit changes because they are connected to the same point.

[bwaslo]

Originally Posted by chris661

Question: Is there a donation page?

My passive speakers have been aided hugely by this software, and since I use them in professional environments (or did, before events were cancelled by the virus), it'd be great to give something back.

Cheers,
Chris

Chris,

Thanks. Anyone wants to donate, do it to the Alzheimer's Association. (My wife doesn't have ALZ, but a similar illness. Closest organization I know of).
Alzheimer's Association | Donate to Fight Alzheimer's Disease