Pioneer DMH-1770NEX Speaker Issues
 

Just to preface, I'm almost clueless when it comes to car audio, but give me a couple pairs of audiophile level headphones and I can tell clear differences.

That being said, I just installed this unit into my 17' 86 a couple days ago. Everything works as far as I can tell, but I noticed some issues with my speakers. When I play music that may have some bass to the track, at higher volumes, enough to help drown out road noise, the audio has a barely noticeable static/distortion from the speaker on the dash. Not that bad, but I notice it and it is very annoying. When I set the EQ and everything to flat, audio is perfect, no static/distortion at all.

It's a brand new HU so there's no information online other than from Pioneer themselves. I'm not looking to add a sub/amp anytime soon as I may end up going the OEM+ route early next year.

My main question is, does adding a new HU in our cars mess how the factory amp/door speakers function? Would upgrading just the speakers potentially help?

I did a search on the forums, so I apologize if the answer is already out there, but every thread I found mentioned aftermarket amps/speakers/subs as part of the installs. Any post with just a HU upgrade said their audio was improved across the board.

if setting the eq to flat fixes the problem, it would indicate it's a head unit processing issue.

but there shouldn't be anything that an aftermarket head unit alters about the sound system other than any pre-programmed eq-curves built into the factory unit.

Did you purchase your 86 new from the dealer, or could you have possibly inherited someone else's audio system modifications when you purchased the car used?

Got it with only 1 previous owner, with records of all maintenance done at the dealer. There were no modifications done to the car from what I can tell. Wiring is all intact. The car looked brand new when I picked it up. 24k miles and it still had most of the factory blue protector wrap on just about everything a new one has. Factory HU was fine. No issues with sound, apart from the horrible rattle in the doors.

I happened to plug in an iPhone for Apple Carplay and from what I could tell the sound issues seemed to go away. My main Android phone is on a beta right now, so there is a slight chance that could be causing issues but BT is working with all my wireless headphones just fine.

My next step is to look into sound deadening for the doors to stop the door rattling so I have a better idea of where other audio issues are coming from.

Do yourself a favor and lift the dash speaker covers and snap a couple of pictures of the midrange and tweeters and post them. Unless you physically look yourself, you won't know for sure if those are the OEM speakers, but we can help you determine if that is the case. Maybe you have a bad capacitor on one of your dash speakers, or maybe even a blown driver.

Pioneer has a reputation for good, clean speaker level signal at moderate to medium-high volume levels and the OEM mids and tweeters in these cars don't normally present much of a load to high power head units in general. Bluetooth isn't really the highest quality sounding source for any head unit, and since that head unit has no CD player, try playing some decent quality wav. files from the USB port and let us know how that sounds.

Snapped a couple pictures. It's definitely stock, I ended up ripping half of the foam covering part of the harness to the tweeter on my driver side.

Attachment 205141

Attachment 205142

Played a couple FLAC files, then played them off my phone through BT. Slight difference in sound. Even with the FLACs Bass still isn't as strong as it was before the Hu swap.

Assuming that the factory amp is operating normally, this almost sounds like a speaker phasing problem especially after speaker connections have been modified. Example: If you have left and right speakers they should both move inwards and outwards at the same time. If the plus and minus wires on just ONE side are inadvertently reversed now one speaker will be moving outwards while the other one is moving inwards. Instead of the sound waves from the left and right adding together and reinforcing each other they are now 180 degrees out of phase and cancelling each other. This is most noticeable at lower bass frequencies with the low notes sounding "weak". The effect is not as noticeable at mid and high frequencies except that the system just sounds "not right" or downright bad.

Try this: Play a recording that is known to have a good bass line. Use the tone controls or EQ to eliminate as much of the mid and high frequencies as possible. Make a mental note of how loud the bass is and then use the balance control to shift everything to either full left or full right. If the bass sounds better/fuller/louder with the balance all the way to one side and weaker/quieter with balance back to center/normal there is probably a phasing problem.

I installed a Pioneer AVH-ZL5150 HU in my 2017 860SE Halo and it works well. Perhaps you've seen the following thread. There is a wealth of information collected in it.

https://www.ft86club.com/forums/showthread.php?t=128548

Just my two cents (and 50 years of experience). :thumbsup:

That could explain the loss of low frequencies after the new head unit installation but it wouldn’t explain the static/distortion from his dash speakers that he brought up in the first post. A blown speaker or bad capacitor might though, or even bad source material to a point.

But you’re right. I walked into one of the local car audio shops near me last year and I could instantly recognize that they had one of the speakers on their display board out of phase. Young kids running the shop. I gave them the plans and materials for my subwoofer enclosure for them to build on their CNC machine, but suffice to say that I will never have them perform any work in MY vehicle. Not that I really need any help with wiring or tuning my system as I have a couple of year’s worth of professional installation expertise under my belt from back in the late 90’s.

Yep, definitely OEM mids and tweets. Do you have a multi-meter that can check capacitance. You might try checking all of your capacitors and inspect the mids for any damage to the suspension or any “crunchy” noise from the voice coils when you push in on each cone. You might as well check the voice coil resistances while you’re in there. As for the two door speakers, how do they sound with the dash speakers disconnected?

i really doubt it's going to be a defective component.

many of the factory radio's now come with preset eq settings to tune the radio to the vehicle it's installed in. if you're using just a flat eq with the new radio, there will be a noticeable difference.

with the pioneer's, very simply try toggling the 'loudness' on/off with the volume down--personally, i find the feature too much, but it might give you the extra oomph that you feel the system has lost. outside of that, you can also try using some of the preset eq curves in the radio to flavor the system to taste. just takes time.