refining my crossover (HELP NEEDED)

[dreadknot]

i need some help with my crossover circuit design such as

does it look correct with the layout for a two way 3rd order butterworth at

400hz

this is for a future build that is to be a set of rear surrounds with this

config

a 4ohm input at 300watts
with 250watts at 2ohm to the lows
an 50watt at 4ohms to the highs with a L-Pad Attenuation of - 4db with a first order lowpass at 1500hz (it is for smoothing out the highs)
an a 2nd order highpass at 16hz with a 1.4q

does this need anything more like a ground or a zobel circuit if an so were

would it go

the drivers to be used are as followed

using two GRS PT6825-8 8" Planar Mid/Tweeter 8 Ohm ( wired to 4ohms )

an one Dayton Audio RSS265HO-44 10" Reference HO DVC Subwoofer (wired

to 2ohms)

an two Dayton Audio RSS265-PR 10" Aluminum Cone Passive Radiator tuned at

16hz

https://imgur.com/a/iv8DeQu

 

[Obiwan]

Hey,
Not sure what you're trying to achieve here, is this a PA-system or just for your own home? You have a whole lot of power going everywhere. Also, I assume you have a very powerful amp for that 2 ohm sub, something like a proper PA-amp or maybe a old Threshold? Any reasonably affordable amp would risk running into some serious distortion working with that low impedance.

 

[Obiwan]

Oops, accidentally posted, not finished yet;-) I strongly suggest reading up on some basic loudspeaker theory, and getting yourself a cheap calibrated mic. Download the excellent REW-program from this forum and you can not only measure SPL to see what your new speakers are doing, but also measure impedance to see what they're doing when not you're not looking (like whether they're actually staying above 2ohms or drifting towards 1, because of the tuning of your ports). The passive element is basically acting as a tuned port in this application. As for the Zobel network, always a good idea, especially if you're not measuring impedance curves. Impedance changes with the box you build around your driver, so you can't really trust the data from the manufacturer. mh-audio.nl has a great site with good explanations and handy calculators.
Be prepared for a good amount of trial-and-error until you get the sound you want.
have fun tinkering!

 

[dreadknot]

ive updated my design concet ignore the prevous config of
a 4ohm input at 300watts
with 250watts at 2ohm to the lows
an 50watt at 4ohms to the highs with a L-Pad Attenuation of - 4db with a first order lowpass at 1500hz (it is for smoothing out the highs)
an a 2nd order highpass at 16hz with a 1.4q

ill be going with a singal planar in vertical at 20watts at 8ohm with a 12db Attenuation crossed at 400hz with 280watts at 2ohm for the lows

this is what im aiming for

im really new to this espeacily in Xsim
the drivers ill be using are per cab with twin rads are

one GRS PT6825-8 8" Planar Mid/Tweeter 8 Ohm

an one Dayton Audio RSS265HO-44 10" Reference HO DVC Subwoofer (wired to 2ohms)

if anyone can design this correctly to get this fq response id be greatful

once designed iv got a guy that can build it for me

 

[Obiwan]

This looks quite sensible. I'd wire the sub in series (8 ohms) to get a more manageable impedance (recalculate values for the XO, of course). No need for a high-pass at 16Hz, very few drivers have any significant output down there anyway. Unless you're able to measure VC impedance (borrow a LCR-meter?) you won't be able to calculate a Zobel network, which BTW is a thing of beauty. The Zobel will make your nice new XO perform as expected, because it flattens the impedance curve. Depending on where you place your crossover f, the impedance of your driver may be way off (as in 20ohm instead of 4). HTH...

 

[dreadknot]

im not going to use a high-pass at 16Hz after all but i do want to use in a 2ohm config foe the sub but how would you design a proper Zobel network an put it in the Xsim curcit graph
could you demonstrate were an how it would go in the design

 

[Obiwan]

There's a good explanation here: mh-audio.nl/Calculators/iec.htm. Not aware of the Xsim software you're refering to. As i said previously, to be able to calculate a Zobel network, you need to measure the inductance of the voice coil...