zaphaudio hivi b3s crossover question...

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i was trying to analyze that filter designed by zaph for the hi-vi b3s project, link here:

http://www.zaphaudio.com/audio-speaker18.html

and i cant figure out what part of the crossover is the high pass part...i think the inductor paired up with the resistor on the first part serves as a low pass for this full range driver....and the next part of the filter seems to be a notch filter, probably to tame some peak....so does this mean that nothing is filtering out the low bass signals? might this damage the driver?

notice: i am NOT criticizing zaph cuz i know he is a genius and everything...i just want to know why he does what he does, so i can learn...
 
The inductor and resistor in parallel form a baffle step compensation network. The other network is a notch filter to remove the cone breakup node at 8kHz.

You don't normally need to filter out the low bass frequencies on a full-range driver, however if you read further down, Zaph says these need a sub with a proper sub crossover as they distort heavily below 100 Hz.
 
If you are going to use a subwoofer, you should use an active highpass crossover for the B3S. This is a common feature in todays receivers, usually enabled by setting your speaker type to small, then configuring the crossover point. Another bonus to this method is the receiver should take the low frequency material that is filtered out and mix it into the subwoofer output.

Using a passive highpass crossover under 200hz for the B3S drivers is possible, but not economical.

What amplifer/receiver do you plan on using?

Dan
 
Hi,

designing high pass crossovers for the satelites in a sub / sat set
up in extremely difficult due to the influence of the sats units bass
resonance.

You haven't read "Use an active subwoofer crossover!" on your link ?

It has a design for a passive high pass.

:) /sreten.
 
Hi,

that section does show how to implement a passive c/o to the satellites.
And that its expensive due to the extra components involved.

http://www.zaphaudio.com/audio-speaker18-passivehighpass.gif
audio-speaker18-passivehighpass.gif


But if you want high power handling it must be done as you
cannot implement any of the other options mentioned.

Note that Co is the capacitor in the plate amplifier.

:)/sreten.
 
Hi,

your just not getting it are you ?

The speaker level high pass on a sub amp is an attempt to design
a "simple high pass filter" and that section of the article shows you
what will happen if you try to do it.

The fact the simple high pass in in the sub and you go via the
sub doesn't make any difference to the end result. Of course
you can add C0 (100uF) to the impedance correction stuff
and wire that directly between your amp and the satellite.

You'll still need a cable run to the sub for its speaker level
input but it will carry a small current so it can be very thin.

:) /sreten.
 
sreten said:
Hi,

your just not getting it are you ?


:) /sreten.

gee, i think if i was getting it....i would stop asking stupid questions....

i guess what i am trying to say is...what is so bad about the impedence spikes that appear when using the 100uf capacitor without the impedence stabilizer? i see two peaks on the impedence graph, but they arent that big...how noticable will these peaks be, and what specifically will they affect? sound? performance?
 
anybody??!...reason i am asking if cuz if it is not ENTIRELY necessary to use the impedence stabilizer circuit, then i am just going to attempt to use a 100uF cap and see how it sounds, and maybe add the rest of it is necessary...

i do NOT want to damage the speakers, so i am asking what precisely happens if u leave peaks like that in the system
 
i am reading...i have read it 7 times now...but the one thing it does not tell me if the one thing i am asking over and over again....

i KNOW its created a peak in the response, but will this peak be dangerous for the speaker? or will the sound quality suffer? or both? why EXACTLY is this peak sooooo bad that i want to pay 20 bucks buying all of the impedence flattening circuit parts to fix it?

if i dont get an answer im just gonna get the 100 uF cap and see what it does on my own....

i dont plan on "measuring" the speakers once they are done but i do plan to listen to them, so if it sounds good i will be content, asthis is my first project, and it doesnt need to be UNBELIEVABLE good sound...
 
jaygeorge1979 said:
i am reading...i have read it 7 times now...but the one thing it does not tell me if the one thing i am asking over and over again....

i KNOW its created a peak in the response, but will this peak be dangerous for the speaker? or will the sound quality suffer? or both? why EXACTLY is this peak sooooo bad that i want to pay 20 bucks buying all of the impedence flattening circuit parts to fix it?

if i dont get an answer im just gonna get the 100 uF cap and see what it does on my own....

i dont plan on "measuring" the speakers once they are done but i do plan to listen to them, so if it sounds good i will be content, asthis is my first project, and it doesnt need to be UNBELIEVABLE good sound...

Sreten, thanks for helping me out here.

jaygeorge,

YES, the peak will be dangerous for the speaker, and YES sound quality will suffer. Whenever bass at the frequency of the peak comes through, the driver will likely exceed Xmax. Additionally, bass at that frquency will have huge amounts of harmonic distortion. And finally, just adding a cap for a crossover will cause a peaky "one note bass" response curve.

The impedance flattening circuit is offered as an expensive and impractical option for those that don't an active subwoofer crossover. Most HT receivers include an active sub crossover, but most stereo receivers do not..

I don't recommend the impedance flattening circuit, for cost reasons. I also don't recommend a single cap for performance reasons. Using a single cap severely compromises the design.

You're fighting with 2 concepts: you don't want to spend a lot of money, but you don't want poor sound either. Sorry, but you have to give up one. In reading your discussions with Sreten, I can see you don't want to give up either, which is frustrating for everyone who tries to help you.

I won't be back to this thread to answer any questions, but I hope this helps you to make a decision on what to do.
 
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