Front JBL speaker trouble? ALSO Amp + Sub PICS

[Cape 4RUNNER]

I have a Kenwood DNX 5120 H/U with the Scosche (sp?) adapter. When I turn the volume up the front speakers turn off and the rear speakers are the only ones on, while at times the front speakers kick back in during the music. This happens regardless of the Scosche wires are plugged into the Kenwood front or rear outputs. Is this a problem with the speakers themselves or Scosche adapter?

In other news I installed my sub! I am running the Alpine M350 amp to one JBL P1022 1600W sub (running both voice coils at 4 Ohms rather than 1 voice coil at 2 Ohm to get more clarity vs. more power). I built the box myself and I know its not to speck with what the sub calls for but I built it for space constraints and chose the sealed box to get greater response and clarity which is good for the variety of music I listen to. The box has anchors that tie it in down that are not visible, but the weight of the box + amp + sub (weighs 35 pounds alone) is around 70 pounds and not going anywhere. Overall the install came out really clean with all the wires hidden and I still can fold down the 60 split seat and retain much of my cargo space.

 

[drmorbius]

I have a Kenwood DNX 5120 H/U with the Scosche (sp?) adapter. When I turn the volume up the front speakers turn off and the rear speakers are the only ones on, while at times the front speakers kick back in during the music. This happens regardless of the Scosche wires are plugged into the Kenwood front or rear outputs. Is this a problem with the speakers themselves or Scosche adapter?

In other news I installed my sub! I am running the Alpine M350 amp to one JBL P1022 1600W sub (running both voice coils at 4 Ohms rather than 1 voice coil at 2 Ohm to get more clarity vs. more power). I built the box myself and I know its not to speck with what the sub calls for but I built it for space constraints and chose the sealed box to get greater response and clarity which is good for the variety of music I listen to. The box has anchors that tie it in down that are not visible, but the weight of the box + amp + sub (weighs 35 pounds alone) is around 70 pounds and not going anywhere. Overall the install came out really clean with all the wires hidden and I still can fold down the 60 split seat and retain much of my cargo space.

The problem wouldn't be with the speakers. There must be a problem with the adapter or the JBL amp. It is possible that there is a wiring problem at the JBL amp input.

 

[Cape 4RUNNER]

I am not sure if its an amp issue- the speakers all work when the volume is at a lower level without and issue, it just seems as if their is too much of a power load to power both front speakers all the other speakers so it just defaults to the rears. I did not have this issue prior to changing the H/U so it makes the adapter seem more of the culprit.

 

[drmorbius]

I am not sure if its an amp issue- the speakers all work when the volume is at a lower level without and issue, it just seems as if their is too much of a power load to power both front speakers all the other speakers so it just defaults to the rears. I did not have this issue prior to changing the H/U so it makes the adapter seem more of the culprit.

It could also be the head unit, are there set up settings for this unit?

 

[riverwolf]

I'll voice my WAG...

I wouldn't have expected it, but it sounds like the JBL amp has protection by individual channel rather than shutting down the whole amp if a protection circuit is triggered.

Since the front amps work at low power, but not high, I would look for a shorted connection somewhere. At low power, those channels aren't drawing enough current to trigger the "short" protection, but as you turn it up, the increased current draw eventually trips the protection.

How did you tie in the Alpine sub amp? Are you running it directly to the head unit or did you splice into the sub out speaker levels of the stock amp? If the latter, that would be a good place to start looking for damaged wiring.

Just an FYI. Since all signal processing takes place in the amp module with the stock system (the Scoshe is redigitizing your Kenwood's line level output) , you may not get the best blend with the stock speakers using the a direct sub signal from the Kenwood head to the Alpine sub. The stock processing includes HP/LP filters to blend the speakers with the sub. The Kenwood's frequency or slope may or may not play nice with the HP filtering being sent to the main speakers.

Oh, yeah...the OCD in me says you need to rotate the JBL driver one notch clockwise to get that logo lined up correctly.

-Brent

 

[drmorbius]

I'll voice my WAG...

I wouldn't have expected it, but it sounds like the JBL amp has protection by individual channel rather than shutting down the whole amp if a protection circuit is triggered.

Since the front amps work at low power, but not high, I would look for a shorted connection somewhere. At low power, those channels aren't drawing enough current to trigger the "short" protection, but as you turn it up, the increased current draw eventually trips the protection.

How did you tie in the Alpine sub amp? Are you running it directly to the head unit or did you splice into the sub out speaker levels of the stock amp? If the latter, that would be a good place to start looking for damaged wiring.

Just an FYI. Since all signal processing takes place in the amp module with the stock system (the Scoshe is redigitizing your Kenwood's line level output) , you may not get the best blend with the stock speakers using the a direct sub signal from the Kenwood head to the Alpine sub. The stock processing includes HP/LP filters to blend the speakers with the sub. The Kenwood's frequency or slope may or may not play nice with the HP filtering being sent to the main speakers.

Oh, yeah...the OCD in me says you need to rotate the JBL driver one notch clockwise to get that logo lined up correctly.

-Brent

I was thinking the same thing , I've had the amps apart and the outputs are TA8254BHQ stereo amps which provide 45 watts per channel into 2 ohm speakers. Each amp pair has thermal shutdown protection as well as out to VCC short, out to GND short, and out to out short protection. It's set up for one stereo pair for front speakers one stereo pair for rear speakers 1/2 stereo pair each for center speaker and cargo tweets and one stereo pair to subwoofer w/dual voice coil. My guess is something is touching the wrong thing in the wiring.

 

[Cape 4RUNNER]

Oh, yeah...the OCD in me says you need to rotate the JBL driver one notch clockwise to get that logo lined up correctly.

-Brent

Haha yeah I have the OCD trigger when I see it, the sub itself has two voice coils so it has the (+) and (-) input on each side of the woofer for each voice coil and I have them wired in series so I need the (+) of one side and the (-) of the other side to connect it in with the speaker box. I did not make the wire long enough so this is the only way I could put the sub with both wires holding put.

Anyways, thanks for all the input guys! Lucky for me the issue was much easier to address. Two things I neglected to do: when your using the Schosche adapter you need to turn the stock H/U volume to 50-75% and make sure that the fade is set to 0 before you take it out. I did not do this, so when I hooked my stock H/U in I noticed the volume was low and that the fade was REAR6. I adjusted the volume and set the fade to 0 and now I am fine and all the speakers work great and the system overall now sounds AWESOME, especially paired with the sub.

I was able to install the sub by using 2 RCA splitters. So usually on the Kenwood h/u the adapter has front L and R and rear L & R plugged into the respective RCA's on the head unit. I put the splitters on the front L&R as to use the rear just for the sub so I have independent control of it. This takes away my ability to use the front and rear fader, but I never use this anyways.

 

[Cape 4RUNNER]

Oh and also just to note, Scosche has AWESOME customer service and quickly helps diagnose any issues you are having. One point I had an issue I though was Scosche and it turned out to be unrelated, but the tech stayed on the line and talked me to the fix anyways. I highly recommend purchasing one of their adapters if you have a JBL system and want to add in an after market H/U, it makes the install a snap and you retain all the quality and clarity of the JBL system.