Head Unit HPF cutting signal to subwoofer?

[shakenbass]

Hi all,

I recently installed a JVC KD-X50BT HU in my car as well as a little Dual 8" Subwoofer enclosure, and a pretty boomy pair of 6x9's in the rear as well.

While the 6x9's can do 100w RMS, I want to keep the bass signals away from them currently as they are only being powered by the head unit, so bass gives them a decent amount of distortion at anything higher than 20 watts going into them. My head unit has a high pass filter setting, which from my knowledge should ONLY cut the lower frequency signals to my rear and front speakers, the subwoofer should be unaffected! However switching the HPF to on absolutely, %100 diminishes the bass in my vehicle, even from the sub. If I watch the subwoofer, I can see it vibrating, and there is a small amount of air displacement coming from the port, so I know its still working. However if I switch the HPF to off again with my hand in front of the port its almost like my hand is suddenly getting ****** into a vacuum, the HPF is cutting all bass to the subwoofer as well while on.

Does anyone have any ideas as to what could be causing this? Is it something wrong with my HU possibly? All my wiring seems correct, so any help would be appreciated!

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[goingdef 10+ year member]

you have your rca's hooked to the front or rear channel instead of sub out is what it sounds like to me.

 

[SplAffair 10+ year member]

you have your rca's hooked to the front or rear channel instead of sub out is what it sounds like to me.

that model only has 2 sets of pre outs. so double check you have your rcas in the specified subwoofer output and make sure the setting on the head unit is set to subwoofer on

 

[shakenbass]

There are two RCA jacks, one is for front speakers and the other is rear/sw, you can only do one or the other from it. My HU L/O mode is indeed set to subwoofer, and subwoofer is set to ON. In fact, the HU takes away the HPF option if subwoofer is set to OFF. So Im absolutely lost :/

 

[SplAffair 10+ year member]

have you checked the rcas themselves? swap in another set see if it changes the sound

 

[TheUnderFighter 10+ year member]

Interesting.... and btw, your 6x9s aren't getting more than 20w RMS from your head unit, so you don't need to worry about that. They are probably Boss or something though, and that's why they sound awful and distorted off of Head unit power.

 

[goingdef 10+ year member]

well h3ll I have no clue then man sounds like something might be wrong with the hu? double check and make sure there hooked to rear and not front or maybe there mislabeled somehow switch them around.

 

[goingdef 10+ year member]

Interesting.... and btw, your 6x9s aren't getting more than 20w RMS from your head unit, so you don't need to worry about that. They are probably Boss or something though, and that's why they sound awful and distorted off of Head unit power.

using a hpf when you don't have enough power is common much like a subsonic cutting your amps work by killing tones you can't hear and underpowered sounds a lot worse then overpowered.

 

[TheUnderFighter 10+ year member]

using a hpf when you don't have enough power is common much like a subsonic cutting your amps work by killing tones you can't hear and underpowered sounds a lot worse then overpowered.

I'm not talking about the HPF any more. He said he wants the bass off of is "100w" speakers because they distort with anything more than 20w of power. But he said they were powered by the HU. So I was letting him know, his HU isn't putting out that much power, so he need not worry about that.

 

[goingdef 10+ year member]

I'm not talking about the HPF any more. He said he wants the bass off of is "100w" speakers because they distort with anything more than 20w of power. But he said they were powered by the HU. So I was letting him know, his HU isn't putting out that much power, so he need not worry about that.

gotcha gotcha I didnt read anything else there my adddddddd is acting up.

 

[shakenbass]

Interesting.... and btw, your 6x9s aren't getting more than 20w RMS from your head unit, so you don't need to worry about that. They are probably Boss or something though, and that's why they sound awful and distorted off of Head unit power.

My rears are actually $160 JBL's They can take 100w RMS and 300w max. My head unit has its volume settings from 1-50, and Ive tested pretty thoroughly that anything over 20-25 gets a decent amount of distortion, which leads me to the conclusion that my HU sets the volume number by watts. The head units RMS power rating is only 20 watts per channel so it makes sense.

The RCA cables are just fine. They send the signal just fine normally, the problem only occurs when I turn the high pass on. The manual states that the HPF should not affect the subwoofer out at all.

EDIT: Forgot to mention, the manual actually says to avoid running the unit for too long above 30 volume. I have to turn on the setting that even lets it go over 30.

 

[maylar 10+ year member]

My rears are actually $160 JBL's They can take 100w RMS and 300w max. My head unit has its volume settings from 1-50, and Ive tested pretty thoroughly that anything over 20-25 gets a decent amount of distortion, which leads me to the conclusion that my HU sets the volume number by watts. The head units RMS power rating is only 20 watts per channel so it makes sense.

Lol... no, the volume numbers are just relative not watts. Do you have any EQ boost set? Boosting the bass level takes away from the max volume you can go. With loudness on and bass set for +3 my HU will clip above 1/3 volume on a 0dB source.

The RCA cables are just fine. They send the signal just fine normally, the problem only occurs when I turn the high pass on. The manual states that the HPF should not affect the subwoofer out at all.

Which leads me to believe you're plugged into the front preouts. Did you doublecheck that?

BTW I don't know what freq my JVC HU has for the HPF but with it on I get no midbass at all from my main speakers. Sub preout is fine though.

EDIT: Forgot to mention, the manual actually says to avoid running the unit for too long above 30 volume. I have to turn on the setting that even lets it go over 30.

The option to limit the max volume to 30 is for people who have small speakers like 3.5's and want to be sure not to overpower them.

 

[shakenbass]

Very late reply, sorry bout this!

Anyhow, I removed my head unit and checked the RCA connection. My RCA cable is undoubtedly running from my rear/subwoofer output to my amplifier. I put the head unit in SUB mode, subwoofer is ON, etc. However, switching the high pass filter on is still literally cutting the signal to my subwoofer. Possibly I have a defective head unit? Because changing the subwoofer level in settings is making no noticeable difference in the bass volume while the subwoofer is on. I ordered this thing from amazon a month ago so I'm past the return policy, I just want it to work :/

 

[keep_hope_alive Premium Member]

Read page 21 of the manual.

http://resources.jvc.com/Resources/00/01/52/GET0786-001B.pdf

L/O mode to SUB W.

Sub.W to ON

Sub.W Level should adjust the sub volume.

then you need to be sure to save these settings. initial settings are for the rear output to be affected by the HPF.

 

[shakenbass]

Read page 21 of the manual.
http://resources.jvc.com/Resources/00/01/52/GET0786-001B.pdf

L/O mode to SUB W.

Sub.W to ON

Sub.W Level should adjust the sub volume.

then you need to be sure to save these settings. initial settings are for the rear output to be affected by the HPF.

L/O Mode is set to SUB.

Subwoofer is set to ON.

LPF is set to 120HZ.

Subwoofer level set to highest possible, 8.

HPF off, subwoofer shakes car.

HPF on, subwoofer stops making sounds.

Should I contact JVC?