DiyMobileAudio.com Car Stereo Forum banner
1 - 5 of 5 Posts

·
Premium Member
Joined
·
550 Posts
Discussion Starter · #1 ·
I have recently installed a JBL MS-8 processor, after having read many of the reviews and several threads on this very forum. My goal was to bump up the factory output level, fix up the sound stage, and add a subwoofer to the system. To be clear, I wanted to both improve the quality and the volume of the factory gear. Please excuse the long(er) winded post here, but I’d prefer to give as much detail as I can up-front than go back/forth with Q & A over that I’ve seen asked by so many others before.

Anyways – back to the new install issue. The MS-8 seemed ideal for this install - so I set to the task; the MS-8 is installed in the right (passenger) footwell directly in front of/below the glove box. I took the dash apart, and ran 16 gauge twisted pair wiring from the factory radio (SYNC, MyFordTouch, in a 2013 Ford Fusion). I ran the factory front left and front right into the speaker level inputs 1 and 2 respectfully. The connections are made roughly 2 inches from the back of the factory ACM (audio control module) using crimped connectors and wrapped in heat-shrink tubing. Cable length is approximately 20 inches or so, run from behind the ACM down the side of the center console and right to the MS-8.

I ran new 16 gauge twisted pair cabling from the MS-8 through the molex connectors to the (still factory) door speakers. I have the MS-8 channel 1 connected to the drivers woofer, 2 to the drivers tweeter, 3 to the passenger woofer and 4 to the passenger tweeter. I ran channel 5,6 to the left,right rear doors, and the subwoofer (the only channel not using the internal MS-8 amp) is on channel 7. The factory tweeters still have the (passive) crossover via soldered-on capacitor - I'm still unsure of the designed cutover frequency but I wasn't overly concerned as my longer term goal is to replace the factory drivers with an as-yet-determined mid and tweeter. Nonetheless the crossover point is not my issue (sorry - am getting there eventually … promise).Noteworthy that while I ran new wiring directly from each driver in the front doors (because I wanted to bi-amp/separate the mid/tweeters), I ran two more pairs back from the MS-8 and connected the rear speakers from their factory connections in the dash behind the ACM. All said and done, the driver’s door has the longest speaker run with the rest of the cabling well under 3 feet long. The power is connected via a fused (and dedicated) 8 gauge power wire direct to the factory battery, and the ground is grounded to a clean (bare metal) ground on the framework of the dash directly above the MS-8 mounting position on the nut/bolt as the factory ground wire was (still is). The ground wire is approx. 16 inches long, with crimped on ring on one end and fork on the other connected to the MS-8. In short – I do not believe there is a cabling issue anywhere. I work for Ford, and was able to source the wiring diagram in order to correctly ascertain the factory speaker outputs I have triple-checked polarity as well, though as I understand it that should not be an issue anyways using the factory (speaker) high level for the inputs. The factory radio outputs 4 channels full-range at 13 watts RMS, I opted to just use the front left/right. All equalization and tone settings are set to zero, fade is set to full-front.

The problem I’m having is noise. I get an awful amplifier hiss/white-noise at higher volumes. It’s not over-powering the actual sound/signal but it’s more than enough to annoy the average person, let alone anyone who would consider themselves an audiophile to any degree. If I keep the MS-8 volume below -30 it’s barely audible (hiss/white noise that is) but still there nonetheless. The problem therein being of course that my output power is dismal at best too, certainly well below the factory output for sure. I’m not entirely sure of the factory impedance, and I don’t know if that could be a factor at all or not.

I read some other posts about issues with noise (airplane whine sound complaints mostly), and noted that I too had both only measured for the driver’s seat position and that I was leaving the measurement microphones plugged in thereafter; given the relatively difficult access to the input side of the MS-8 I had left the headset plugged in (stowed in the glovebox) with the wire coming through from behind the glovebox. I had also read several suggestions to use the aux input and try that as well. So I have since re-calibrated several times, for both driver and passenger listening positions, un-plugged the headset, and attempted to use my iPhone connected directly to the aux input. Notably, there is no such noise issue when using the aux input – so I’m fairly confident my issue is between the factory ACM (stereo/head unit if you will) and the MS-8… I’m just at a loss for what to do to fix it. I get OK / OK / OK at about 75% volume on the factory unit during calibration, I have tweaked the crossover points here and there a bit, but currently have my sub at 65hz down, and the fronts crossed over at 1000hz. It sounds ok – but not great, appears to be a hole somewhere I can’t quite figure out and I’m assuming that’s a mis-match between the factory passive crossover point on the tweeters and that which I’m configuring on the MS-8 – that problem I can live with until I replace the drivers. Overall though it sounds very hollow-ish, like the early home theatre surround-sound-emulators “hall” mode – not at all what I expected, very much like the whole audio track is being played through either a cardboard sono-tube or a p.a. horn depending on low/high frequency. The soundstage seems drastically improved but the sound quality way out of sync in the process. I was really hoping for a fairly decent auto-tune with perhaps some minor eq tweaking for an ultimately drastic improvement over the stock sound setup – but alas I’m feeling not much more than a huge disappointment. I’m really hoping there’s something I’m missing but I can’t seem to put my finger on it…. Thoughts/suggestions?
 

·
Premium Member
Joined
·
4,235 Posts
Best to try to determine the source of the noise. Since you have no noise with the Aux in, I think it's the input EQ boosting the treble to correct a big cut in the treble from the head unit. Try boosting the treble on the head and recalibrating MS-8's input. At what level are you using the factory head unit's volume control , 75%?
 

·
Premium Member
Joined
·
550 Posts
Discussion Starter · #3 ·
Andy - I was really hoping you'd chime in ... your reputation on this forum definitely precedes you

I’ll try to re-calibrate tonight as you mentioned with the treble turned up a bit. The factory unit has a bias towards the lower 2/3 of the volume dial towards a heavier bass end, and sort of drops the bass notes on the floor for the last third incrementally as you gain.

The biggest problem I have there is the gain issue with the MS-8 – I’ve been able to tweak crossover points, re-calibrate, tweak, etc and get it to a reasonable amount now, but I have to keep the MS-8 at -22, so the stock volume needs to be in the upper third most region to be at a desirable level, what you’re suggesting seems very plausible as part of the problem then the more I think about it. The procedure goes: configure inputs, crank the volume – get ok / ok / ok, turn down the volume, calibrate/measure positions… I think the turn down there is messing with the EQ going into the MS-8 and as you mentioned might be part if not most of the problem. I’m eager to try your suggestion ever more so but I’m stuck at work for a few hours yet at least.

Regarding clicks and pops – it’s noteworthy that I don’t have any pop / turn on amplifier noise; I’m using the MS-8’s speaker-level (amplified) outputs for now, the only amp I have is on my sub and it it turned on by the MS-8. Sadly, the MS-8’s turn on (remote in) is presently connected to a dongle with a cigarette adapter tied to it because I’ve been as yet unable to source an ACC input on this car (soooo frustrating, but nearly every component in this car is power - on batt always and communicates via CAN bus, even things like window switches, for turn on/off settings). I think I’ve finally come up with a solution to my MS-8 amp remote turn on issue nonetheless – noting that the MS-8 says it can accept 4+ volts for the turn-on, I’m thinking of attempting to use the auxiliary USB connector on the rear of the SYNC HU to pass the 5Volt output out – I don’t suppose you know how much current the MS-8 is going to sink at 5vdc do you? If not, I can always test using a dmm as I doubt it would be more than a few hundred milliamps at best – I just need to assert that it will stay under the 500ma ceiling that the SYNC USB port can provide.

Full disclosure here in that the amp which is presently connected to my sub was just a junk/scrap one I had lying around while I’m still waiting for my intended amplifier (Zapco DC500.1) to show up in the mail. I do get a (faint) pop when that amp shuts off – but otherwise no complaints and I really couldn’t care less about that part. I get the new amp tomorrow actually – so following that the plan will be to first replace the front mids and tweets (not sure what with yet), and then add amplification for the front stage all around (which will presumably make a substantial improvement on my volume/output levels).

Overall I was very disappointed by my first impressions with the MS-8 but the more I tweak/mess the better it’s getting. I’m still totally on the fence over adding a center channel and enabling L7 on it though – thus far not impressed at all with the 4 channels using L7, but my car was designed for a premium (Sony branded) sound setup which does use a center channel, so there’s an ideal location and even a factory grill option if I want to add one… any thoughts on the center option?
 

·
Premium Member
Joined
·
4,235 Posts
If you're going to use the factory volume control, MS-8's control should be sat at -6 or so. Of course there's no gain when you turn MS-8 down by 20dB.

Check to be sure that the crossover on your sub amp is either off or set to the highest frequency available. Then, recalibrate. Since the head unit has a bunch of bass boost, calibrate at the highest volume that still reads OK OK OK. That may help with the treble noise from the head unit.
 

·
Premium Member
Joined
·
550 Posts
Discussion Starter · #5 ·
It's nearly 3:30 am here and I gotta get up for work in about three and a half hours (assuming I go to sleep first of course that is) ... but I couldn't resist so I took some of your earlier suggestions into account and re-tuned a few times. I will again mess with it tomorrow and ideally get my new sub amp wired up too.

I found I was able to significantly drop the noise by boosting the treble up before calibrating. I also took apart the doors, and bypassed the passive crossovers on the tweeters. My best guess, (based on the dc resistance of the tweeter coil and an educated adjustment to be closer to AC impedance), puts the factory Ford tweeters at 6ohm - given the 6.8mf cap they had that puts their crossover frequency at 3900hz. So I've re-calibrated the MS-8 as such:

HU treble +3 (/5 notches upwards)
HU volume at approx 75%
MS-8 volume at -10

Front Lo - 65hz - 4000hz @ 6db
Front High - 4000hz + @ 18db
Sub - 65hz down @ 24db, present amp has un-defeatable crossover and bass-boost, set crossover to highest point (approx 250hz) and bass boost to lowest/zero.

I managed to get my remote turn on working (yay) via my USB idea ... cut a USB cable, soldered fork on it and wired between the spare USB plug on the back of the HU and the MS-* remote turn on.

Measured for drivers & passengers seat. Oddly enough after the tune, doing some seat time with the EQ, L7 off, and my HU treble back to zero - I'm finding I like the overall sound better leaving it on the passenger setting. I've removed the MS-8 screen and am intent upon using the HU volume (this was actually one of the key features that drew me to the MS-8 over the Audison Bit One). I removed the microphones/headset as well after measuring.

The noise is drastically reduced, but still there and quite audible at higher volumes. I presently have the MS-8 set to -16 and it's very tolerable compared to yesterday. My volume/output levels are quite acceptable now too (cannot max the volume dial before the factory speakers start to distort now). I'll hopefully spend some more time tweaking this weekend and report back - I'll try your suggestion of calibrating at -6 and see if that helps any.

My HU seems to carry low frequency very well up until a very specific point in the volume dial (approx just passed the 2/3 point), at which point it starts to just drop the bass bias, from what my ears are able to ascertain it's not boosting treble as much as tapering off the bass. My new sub amp (Zapco DC Reference 500.1) has a built-in DSP which allows for a parametric EQ setting which can vary by input volume... I was thinking I might very well be able to correct the behavior of the HU with that, but wasn't sure what kind of issues I might run into conflict-wise with what the MS-8 is doing ... thoughts?

I'm going to try your suggestion of re-running calibration again with highest level of OK/OK/OK versus lowest as I've been doing thus far and see how much that helps too.

Thanks so much for all your assistance on this - I genuinely appreciate the feedback :)
 
1 - 5 of 5 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top