Rca outputs/ headunit crossover

[Bass so loud it HZ]

I recently install a 4 channel amp with a set of super tweets on the dash and a pair of 6.5s in the front doors. I have rcas running from the front rca output on my headunit to a pair of spliters into my other 2 channels on my amp .I just got a new set of 4 channel rcas. How should i run the rcas? I have front and rear outputs but my vehicle is walled so i have no back stage. Should i run my tweeters off the front rca outs and my 6.5s off of the rear rca outs? If i do it that way does the tweeter crossover on my headunit do anything or will i just have the rear and front crossovers and just have to crossover at the amp ? Super confused any help is appreciatted. Tia!

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[Doxquzme Premium Member]

The front and back are only relative to the fader function on the HU. You can use that as a means to adjust volume top to bottom, 6.5's to bullets instead. Instead of thinking of the fader as front to back, in your situation, they would be relative to the 6.5's and the tweeters instead. Kind of cheap volume EQ. I would run the tweets and midbass according to what options are on the HU and the amplifier. What amplifier are you hooking the HU up to?

 

[Bass so loud it HZ]

The front and back are only relative to the fader function on the HU. You can use that as a means to adjust volume top to bottom, 6.5's to bullets instead. Instead of thinking of the fader as front to back, in your situation, they would be relative to the 6.5's and the tweeters instead. Kind of cheap volume EQ. I would run the tweets and midbass according to what options are on the HU and the amplifier. What amplifier are you hooking the HU up to?

Its the surge 2k 4 channel off of a kenwood kmm bt 328 U.

 

[Doxquzme Premium Member]

Nice amp, okay. All for channels have the same functionality and the option to cross at multiple frequencies.

Which tweeters and which 6.5’s are you using and are you using a cap on the tweeters and if so, what is the uF value printed on the cap?

 

[Bass so loud it HZ]

Nice amp, okay. All for channels have the same functionality and the option to cross at multiple frequencies.

Which tweeters and which 6.5’s are you using and are you using a cap on the tweeters and if so, what is the uF value printed on the cap?

I have a set of deafbonce arnold 6.5 M67ac one in each front door and a set of deafbonce t25 tweeters. I have the D4S 6khz -12db crossovers on the t25s.

 

[Doxquzme Premium Member]

Okay, so with this amplifier, you can eliminate the inline x-over (recommended) as the amplifier is better at doing this prior to the signal going to the tweeter. To keep things straight in your head, we'll dedicate the front HU channels to the tweeters (channels 1/2) and the rear HU RCA channels to the midbass units (channels 3/4). There are additional options for using the inline x-overs too, will have to address that if you decide to use them after all.

If your HU has the option to set the front and rears for HP and LP, then set the fronts to HP at 6000 and channels 3/4 LP at 6000 and leave all the amplifier filters off except the HP filter on channels 3/4. Set the HP on 3/4 to the X1 position and the dial to get you to around 100hz (20hz is all the way to the left).

This creates a bandpass filter of 100hz to 6 khz for the mids and a HP filter with a crossover point of 6K for the tweeters. If you don't have that option, then you'll be using the amps filters to create the same thing, a little bit different and if you're not familiar or unsure, take it to a shop and flip them $50 to adjust the amps filters. If you're comfortable with adjusting the amps filter settings, here is my recommendation.

Pay attention to the amp markings as the channel 1/2 RCA input is top and bottom left even though the controls are the top left to right. RCA inputs 3/4 are on the right, top to bottom and the controls are on the lower of the two, right to left. Keep this in mind when wiring up the speakers too, 1/2 will be the R/L tweeter and 3/4 the R/L 6.5's. (The red RCA usually designates the right side and white is left)

Channels 1/2:

You will set the the LP filter to "OFF" and HP filter to "ON" and the "X" times switch to the x10 position. that gives you a crossover range starting at 200 Hz up to 8kz so you'll want to start it with the dial adjustment all the way to the right at 8000 Hz. 200hz to 8khz is a really wide band and you'll need to be careful but turn it on all the way to the right to start and gradually make your way left, maybe the 3:00 - 4 O'clock position. Given the range, it's probably pretty sensitive and will not need to be moved a lot, you'll have to gauge it.

Channels 3/4:

This s a little trickier as your 6.5's are really pro style mids with a frequency range of 100-15000 hz so I'm going with a bandpass option, 100 to 6000 hz. On the midbass driver, you could work with the settings for the top end response in the 6-8k region, adjust to taste.


For channels 3/4, you will set the the HP filter to "ON" and the "X-times" switch to the "X1" position. That gives you a crossover range of 20 hz to 800 hz. (passes high frequencies starting from 20 hz to 800 hz depending on the setting you dial in)

Set the dial to about the 12 O'clock point, dialing it back (left) to around I'm guessing around the 8 - 10 O'clock position trying to reach that 100 hz point, you'll want to listen at moderate volumes and determine if they start to distort when there is bass material, then dial them further right a bit, thinking that 9-10 O'clock may be that position point.

For the LP filter (passes all frequencies lower than the desired x-over point), you will set the the LP filter to "ON" and the "X-times" switch to the "X10" position. That gives you a low frequency pass range of 2 khz to 8 khz. Start it at the far right position (8kz and dial it left going from a high end of 8 khz down to optimally, around 6 khz.

Set the gains for optimal output just short of clipping for both, not a fan of trying to eek out a few extra watts by allowing the amp to momentarily clip (ever), not worth the risk, especially if you're not a seasoned pro and know how that can be done successfully.

 

[Bass so loud it HZ]

Okay, so with this amplifier, you can eliminate the inline x-over (recommended) as the amplifier is better at doing this prior to the signal going to the tweeter. To keep things straight in your head, will dedicate the front HU channels to the tweeters (channels 1/2) and the rear HU RCA channels to the midbass units (channels 3/4). There are additional options for using the inline x-overs too, will have to address that is you decide to use them after all.

If your HU has the option to set the front and rears for HP and LP, then set the fronts to HP at 6000 and channels 3/4 LP at 6000 and leave all the amplifier filters off except the HP filter on channels 3/4. Set the HP on 3/4 to the X1 position and the dial to get you to around 100hz (20hz is all the way to the left).

This creates a bandpass filter of 100hz to 6khz for the mids and a HP filter of 6K for the tweeters. If you don't have that option, they you'll be using the amps filters to create the same thing, a little bit different and if you're not familiar or unsure, take it to a shop and flip them $50 to adjust the amps filters. If you're comfortable with adjusting the amps filter settings, here is my recomendation.

Pay attention to the amp markings as the channel 1/2 RCA input is top and bottom left even though the controls are the top left to right. RCA inputs 3/4 are on the right, top to bottom and the controls are on the lower of the two, right to left. Keep this in mind when wiring up the speakers too, 1/2 will be the R/L tweeter and 3/4 the R/L 6.5's. (The red RCA usually designates the right side and white is left)

Channels 1/2:

You will set the the LP filter to "OFF" and HP filter to "ON" and the "X" times switch to the x10 position. that gives you a crossover range starting at 200 Hz up to 8kz so you'll want to start it with the dial adjustment all the way to the right at 8000 Hz. 200hz to 8khz is a really wide band and you'll need to be careful but turn it on all the way to the right to start and gradually make your way left, maybe the 3:00 - 4 O'clock position. Given the range, it's probably pretty sensitive and will not need to be moved a lot, you'll have to gauge it.

Channels 3/4:

This s a little trickier as your 6.5's are really pro style mids with a frequency range of 100-15000 hz so I'm going with a bandpass option, 100 to 6000 hz. On the midbass driver, you could work with the settings for the top end response in the 6-8k region, adjust to taste.


For channels 3/4, you will set the the HP filter to "ON" and the "X-times" switch to the "X1" position. That gives you a crossover range of 20 hz to 800 hz. (passes high frequencies starting from 20 hz up to 800 hz depending on the setting you dial in)

Set the dial to about the 12 O'clock point, dialing it back (left) to around I'm guessing around the 8 - 10 O'clock position trying to reach that 100 hz point, you'll want to listen at moderate volumes and determine if they start to distort when there is bass material, then dial them further right a bit, thinking that 9-10 O'clock may be that position point.

For the LP filter (passes all frequencies lower than the desired x-over point), you will set the the LP filter to "ON" and the "X-times" switch to the "X10" position. That gives you a low frequency pass range of 2 khz to 8 khz. Start it at the far right position (8kz and dial it left going from a high end of 8 khz down to optimally, around 6 khz.

Set the gains for optimal output just short of clipping for both, not a fan of trying to eek out a few extra watts by allowing the amp to momentarily clip (ever), not worth the risk, especially if you're not a seasoned pro and know how that can be done successfully.

Hell yeah man i really appreciatte you taking the time to explain it all to me!! I compete in spl comps with a right around 160db build but ive never done mids and highs which is kinda different. im not new to this so i understand what your saying just not educated in this area. The highest i can go on my hpf for my front and rear speakers on my headunit is 250 but it has a tweeter frq also that i can set although idk if it really does much . Thats where i get real confused will that intefere with my amp crossovers beings i cannot turn it off ? Other wise i can just set hpf to 6k for the tweeters with lpf off .on the 6.5s Hpf to 6k lpf to 100 correct?

 

[Doxquzme Premium Member]

I am assuming that the HU filter at 250 is a LP filter, allowing anything below 250 hz to "pass". so good for subs, not for a midbass, looks like you'll need to use the amp filters then. if you cannot set both channels to full, then set the tweeter (front R/L) tweeter filter to 4000 hz and leave the rears on full pass.

Since you're going to use the filters on the amp, then set them. as I stated as you have recapped it backwards

The terms can be confusing, so remember that a HP allows the "higher than" to pass, LP allows the "lower than" to pass. Since we don't want anything on the 6.5s to pass below 100, set the LP filter to 6k (everything LOWER than 6k passes, and the HP filter to 100 (allows everything above 100 to pass) giving you a 100 hz to 6kz bandpass filter.

I know it seems the terms LP and HP (on their face) seem counterintuitive and even knowing what I know I have to re-check my thoughts over and over again in my head to make sure. Bandpass settings don't help one see this any clearer for sure. I think what trips people up is that the word high means high frequency and in HP filter it usually does but, actually it means frequency that is high-er than the point selected. LP allows frequencies low-er than the chosen point to pass,

Just remember:
LP allows anything lower than the crossover point to "pass".
HP allows anything higher than the crossover point to "pass"
BP allows a certain band above and below their respective crossover points to "pass"

Now to help confuse you more, subsonic filters are actually HP filters as they allow only frequencies above say, 5-35 hz to pass. That is why on most of your mono sub amps you actually have the option for a single mono bandpass filter, say,, from 20 hz to 80 hz.

in that situation, you would set the HP (Subsonic filter) to 20 allowing all the frequencies higher than, (not high frequencies per se) but higher than 20 hz to pass, and on the other end, the LP filter is set to 80 hz,allowing everything below 80 hz to pass and vuala, 20 hz to 80 hz bandpass filter.

 

[Doxquzme Premium Member]

On another note, if you're competing in SPL, you might want to check around at what the best crossover point is. These two drivers (your 6.5s and your bullet tweeters) are very close, efficiency wise so you may get more points on the meter by moving it from the 6k to say 8k. 8k is the limit on the amps filter but I don't know enough about SPL competitions to know what moves the meter. Some might suggest that you remove the LP filter on the 6.5s altogether and let them roll off naturally on the high end, I really don't know what they measure or look for in those SPL competitions. I have recommended the setting in accordance with the tweeter optimal SQL recommendations. I would not go any lower on the tweeter than the 6k as the amp uses only 12db slope, 6K is as low as I would go unless someone in here knows better and can offer a recommendation.