Crossover questions

[jsayre914]

Hi Guys,

Been awhile, loooooong story. The short story, I built the engine for my Porsche less than 1000k miles and I blew it up. Now I got help and had it built again. This is the 4th engine since I bought the car. Im starting to think I drive it pretty hard lol.

Now my questions.

The alpine head has crossover settings, the amps have crossover settings, the components have another crossover, and the EQ can cut frequencys on top of all of it. I am trying to figure out how to get the best balance over the whole bandwidth. I am pretty good at making things more complicated than they need to be.

I am running 1 6.5 rsd component set and 2 rsdc 12 woofers.

I have all xs amps wich come stock with a 80hz crossover I think. I started from scratch today, tuning. I used the headunit to set the crossover for the components. I tried 80 then 100 then 125. I am a beginner keep in mind, I have found the higher I set the crossover the louder I can go with little distortion, but then I get a dead spot in the middle. So I set the woofer from 80 to 120 to fill the gap, it does a little, but not exactly. Then I tried from 120 to 160 on the sub and it got too muddy (is that a good word for it)

Then I tried overlapping the highs set at 100 and the sub at 120hz

I am driving myself crazy here.

Then I started using the crossover on the amps 80 for low and 80 for high, the rsd 6.5s do not like 80 and they pop with too much volume. Now I am using a combo of head crossover and amp crossover, I cant even here a difference.

I know every system is different, depends on the vehicle, placment, etc, etc.

Where would you start ???

[trickyricky]

If your head unit has crossover options why not just by-pass the crossover on the XS amps? You can also purchase those resistor networks for the amps if you wish to change the crossover point.

Using two crossovers (both head unit and amp) will cause a steeper slope especially if both are set at the same point. Sorry that I wasn't much help, others will chime in and help.

[Kirghiz]

On a two way system most folks set the line in the ballpark of 80hz. The reason is much over that and you start to hear where the bass is coming from rather than maintaining the illusion that all of the sound is coming from your mids. You actually can set the subs at 60hz and set your mids at 150hz and get the benefit you were talking about, but you would need another set of drivers to fill that hole, which is called midbass drivers, and that becomes a 3 way system.

If you don't want to add more drivers, I would set it between 70-80hz and call it a day.

[stipud]

Sounding like there is a gap could also be phase/time alignment. Try swapping the leads on your sub to see if you hear an improvement.

[jsayre914]

On a two way system most folks set the line in the ballpark of 80hz. The reason is much over that and you start to hear where the bass is coming from rather than maintaining the illusion that all of the sound is coming from your mids. You actually can set the subs at 60hz and set your mids at 150hz and get the benefit you were talking about, but you would need another set of drivers to fill that hole, which is called midbass drivers, and that becomes a 3 way system.

If you don't want to add more drivers, I would set it between 70-80hz and call it a day.

I have a unique ride, the tweets are on the dash bouncing off the windscreen, the 6.5s are in kicks and the 2 12's are in the front trunk My whole stage is right in front of the driver, knowing that.... my thought was to bypass the xs crossovers and set the subs at 100 with 24db and then set the component at 80 with 24db. I have been playing around with the headunit, there is sooooo much options. I want a full sound, i want a punch in the chest and I dont want a heavy bottom end.

Sublime is my latest tuning CD



Joseph

[ReneBMW]

Normally i have sub crossed @80 -18, kick (9inch morel) from 80 -30db to 300hz -18, mids (ti elite 5) from 300hz -30 to 4000hz -30db and the kenwood tweets (I know...) from 4000hz -18db.
But as I am building my under-seat enclosures for the kick I currently run the sub at 125hz -6db, mids 125hz -30db ( otherwise they start to "pop" at high volumes) to 2800hz -18db and the tweets realy low at 2800 at -30db. (Realy good staging and no harshness from the high mids)
You should keep you crossoverpoints the same and only use 1 source to set the crossover for accuracy and simplicity.
IMO it's best to set all from the headunit, if possible.
Otherwise set your sub at the desired point on your head unit, example 80 hz, then set your highpass at 80 hz also, and let the passive crossovers do the work they are designed for.
Or leave the headunit alone and adjust all from the amplifiers.
But IMO, if you set sub at 80 you get no kickbass.
But wich ever way you go, a sub matched with a two way system with a 5 inch midrange will NEVER be ideal.
You sacrifice some sound one way or the other, even with a 6 inch you never get it perfect, that's why a lot use 2 midranges.
Better is to get some 8's or 9's.
IMO the best sollution for a two way system is setting the sub lowpass high, at 125, and the frontspeakers at 125hz, with the disadvantage that uou can slightly hear where the higher bass notes are coming from.
If you realy want all frequencys covered, get some kicksubs.
In the end it's what you like the best offcourse!

[ReneBMW]

But whatever you do, dont use crossover on more than 1 device, you Will totally f.... Up your sound

[jsayre914]

IMO the best sollution for a two way system is setting the sub lowpass high, at 125, and the frontspeakers at 125hz, with the disadvantage that uou can slightly hear where the higher bass notes are coming from.
If you realy want all frequencys covered, get some kicksubs.
In the end it's what you like the best offcourse!

Thanks for the reply

I set everything up just like you suggested, and it sounds pretty good. Sub @ 125 18db was hitting the higher notes a bit too loud, when I tried it at 125 24db it got better. I get great (kick bass) now but the lowest sub notes dont seem to play as lound.

What does the bass boost on the amp do ? I have never used it before, but I am thinking that in my setup it may help. Does it just boost the lower frequencys and if so , wich frequencys. (XS 2500) or should I leave everything as is, and save up for some 8inchers. I dont want to overwoork the amp or the subs, but I would like to understand the boost knob on the amp.

Thanks

Joseph

[trickyricky]

0 to +18db @45hz, I would leave the bass boost alone unless their dedicated for subwoofer duty or lack that certain fhz.

[ReneBMW]

Nice, great that i can contribute to to this forum!
Like tricky says, better to leave the bass boost alone
Or set it jut slightly, but then don't push the volume way up.
If you have a (to small) sealed enclosure the cutoff frequency tends to get higher, and you can get a peak in the higher bass notes, wich will,(if to much) sound rumbly, or muddy as you say.
The loss in response after the frequency cutts off you could adjust this slightly with the bassboost, if, lets say, frequency cuts of 1 octave above the bassboost frequency, you loose -3 db or more.
You could adjust for this but that bassboostknop isn't accurate enough to set it propperly.
And keep in mind, your amp will still power these frequencuys at the same power, your sub will see the same power, the only thing is, you don't HEAR it.
So if you set bassboost and boost that frequency with say +3 db, you use double the power, another 3 db and it will use another double the power. Every +3 decibel needs double the power.
So it's possible that your amp is going to work to hard when you hit those low note realy hard.
I don't know how to explain this better, maybe I missed something...
Good luck with the system!
Glad it seems to work out for you!
Just play a bit with crossover slopes and you will get what you want eventualy