refining my crossover (HELP NEEDED)

[johnny45]

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

http://imgur.com/a/iv8DeQu

 

[Mark E. Long]

Cant help you at all but great looking build on the cabs .

 

[johnny45]

THANKS

 

[lovinthehd]

More a diy subforum topic but maybe someone like @TLS Guy or @Swerd can comment....over my pay grade.

 

[Mark E. Long]

More a diy subforum topic but maybe someone like @TLS Guy or @Swerd can comment....over my pay grade.

Me too nice job on the cabs tho !

 

[lovinthehd]

Me too nice job on the cabs tho !

Maybe, depends on drivers/crossover design....they're pretty, tho.

 

[Mark E. Long]

Maybe, depends on drivers/crossover design....they're pretty, tho.

Yea they are impressive cab build too .

 

[TLS Guy]

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

http://imgur.com/a/iv8DeQu

View attachment 47479

View attachment 47480

View attachment 47481



View attachment 47483

View attachment 47484

View attachment 47485

I'm busy at the moment. I will try and design a crossover for those speakers for you. Unfortunately you have significant misunderstandings. For instance you can't make a third order crossover and series another, and think they are independent. All components are interactive. For instance your low pass crossover is fifth order. That will have huge time shifts. That is just not a good solution at all.

I will try and see what I can do, if there is enough good data on your drivers to be able to design a crossover. What I see of your circuits make no sense to me at all. Hopefully the component count can be significantly reduced.

If you design a speaker again, then you do need a good model for the crossover before you cut wood. The reason is that it may not be possible to actually design a workable crossover for the drivers you have selected.

 

[johnny45]

I'm busy at the moment. I will try and design a crossover for those speakers for you. Unfortunately you have significant misunderstandings. For instance you can't make a third order crossover and series another, and think they are independent. All components are interactive. For instance your low pass crossover is fifth order. That will have huge time shifts. That is just not a good solution at all.

I will try and see what I can do, if there is enough good data on your drivers to be able to design a crossover. What I see of your circuits make no sense to me at all. Hopefully the component count can be significantly reduced.

If you design a speaker again, then you do need a good model for the crossover before you cut wood. The reason is that it may not be possible to actually design a workable crossover for the drivers you have selected.

its really first time using Xsim to model a curcit
what i was going for is this

this is the driver response with the 1500hz 1st order low pass

vs without the 1500hz 1st order lowpass

i dont know how or if the a way to add a parometric q filter effect to flaten the fq out in the crossover which is was id prefur id also like to add to the xover a highpass filter of what ever would constant in a trim control at 25hz to control the drivers cone excursion from exceeding its limit

 

[TLS Guy]

its really first time using Xsim to model a curcit
what i was going for is this

this is the driver response with the 1500hz 1st order low pass
View attachment 47540 vs without the 1500hz 1st order lowpass View attachment 47541 i dont know how or if the a way to add a parometric q filter effect to flaten the fq out in the crossover which is was id prefur id also like to add to the xover a highpass filter of what ever would constant in a trim control at 25hz to control the drivers cone excursion from exceeding its limit

You have two major problems.

The first is the power handling of those tweeters. I know you are using two, but those type of drivers do not handle power well in the lower range. The power divide is 400 Hz, and there is significant power below the crossover point even with a fourth order crossover. So the crossover needs to be raised to 600 Hz at least.
In addition that horizontal layout of the tweeters is going to cause you a massive lobing/dispersion problem. They are just not designed to work that way. So they will beam fiercely in the horizontal plain and disperse in the vertical plain which is the opposite of what you want.

I know that bass driver well as I own one and use in the in wall TL sub. I can tell you that a crossover above 200 Hz is less than optimal for that driver. I would say that your driver selection was far from optimal. You are after all making a two way speaker using a sub driver!

I will model this over the weekend and see how it can be optimized.

 

[johnny45]

inregurds to the dayton sub do you think that the
SB Acoustics SW26DBAC76-3-DV 10" Subwoofer
would be better suited to be xed'over at 400hz or as you said more optimal 600hz
thers no frd file for me to model in Xsim so if can tell me based on its driver spec i dont know how to read it if it can

an if i were to flip the planars from horizontal to vertical an switch from a 2way at 400 or 600hz to 3way at 600hz/1500hz by use one of them as a midrange would i still get lobing/dispersion problems

 

[TLS Guy]

inregurds to the dayton sub do you think that the
SB Acoustics SW26DBAC76-3-DV 10" Subwoofer
would be better suited to be xed'over at 400hz or as you said more optimal 600hz
thers no frd file for me to model in Xsim so if can tell me based on its driver spec i dont know how to read it if it can

an if i were to flip the planars from horizontal to vertical an switch from a 2way at 400 or 600hz to 3way at 600hz/1500hz by use one of them as a midrange would i still get lobing/dispersion problems

Just give me a chance to look at this. Certainly placing the tweeter vertical will help a lot. It would be better if there was just one. There is a fundamental problem you have though. Planar drivers are very limited in their low end power handling. So I see why you need two.

What I find really hard to understand is why you want to use sub drivers in a two way system, especially as surrounds. That seems a significant mistake to me.
You are far further ahead with a two way crossed between 2k and 3 K and the higher the better. After all the drivers you picked are not spectacular in a sealed box anyway.

My surrounds are 2.5 way with 6" drivers with an F3 of 52 Hz, but they are only 12 db down in the mid twenties and that is fine. They are very high powered older Dynaudio drivers and are very good speakers. They do not sound in the least bass deficient. There really is a lot of power all the way from 80 Hz to 2.5 KHz. So that range is best handled by a robust driver, or drivers. That means a bass mid, or a potent midrange to carry the speech discrimination band from the 350 Hz/500 Hz range to 3.5 KHz to 3.5 to 4 KHz. I think people really neglect to look at the power distribution curve of speakers, and really understand where power is required, and it is NOT below 80 Hz. I have to say I'm really concerned about what the low distortion output of that design will be from 400 to 2 KHz especially. You still have to move significant air at those frequencies.

 

[johnny45]

do you know if the Dayton Audio RSS265HF-4 is optimal up to 800hz vs the optimal function of the RSS265HO-44 200hz that you mentioned

 

[TLS Guy]

do you know if the Dayton Audio RSS265HF-4 is optimal up to 800hz vs the optimal function of the RSS265HO-44 200hz that you mentioned

Well, I have played extensively with mine. I have to say the sound develops a definite character as you play that driver above 200 Hz, and certainly over 250 Hz. From its construction, that is what you would expect. I don't think the designers had any thought in their heads, that someone would use it in a two way design. You go about designing sub drivers very differently from bass drivers. Bass drivers are not sub drivers, and sub drivers are not bass drivers.

 

[johnny45]

OK

 

[johnny45]

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

 

[TLS Guy]

OK, I have wasted a full afternoon trying to make a workable crossover. It is NOT possible to make a passive crossover work for that driver combination.

The problem is that for both drivers, the DC resistances of that combination are too low. So for the component values required for a 400 Hz crossover the DC resistances of both the caps and inductors are just too high a proportion of the DC resistances to make any practical passive crossover.

So if you really mean to do this, an active design using electronic crossover and high and low pass amps is mandatory. There is no passive solution.

Honestly that combination of drivers is not worth the trouble. As I said previously you selected a sub driver for a two way system that was not a good idea.

Putting those planar drivers side by side will produce a system awash in comb filtering response aberrations. If you want to use two, they have to be in line vertically, so they create a line source.

So I have to be honest with you, that you have come up with an impractical and poor design on many fronts.

 

[Jerkface]

Putting those planar drivers side by side will produce a system awash in comb filtering response aberrations. If you want to use two, they have to be in line vertically, so they create a line source.

So I have to be honest with you, that you have come up with an impractical and poor design on many fronts.

Couldn't he switch over to horns, convert to 3-way, and salvage what otherwise is a beautiful cabinet build?

 

[lovinthehd]

Couldn't he switch over to horns, convert to 3-way, and salvage what otherwise is a beautiful cabinet build?

Is it a cabinet build or just a computer aided design in picture form?

 

[Jerkface]

Is it a cabinet build or just a computer aided design in picture form?

Good question. Hopefully it's the latter, since the desired outcome is completely unworkable.