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Discussion Starter · #1 · (Edited)
After too many experiments over an extended period of time, my system finally sounds like the musicians are on the hood. So I wanted to pass along a cheat sheet in case it helps someone in the future.

All this information is probably available in other places but, either I didn’t understand it completely or I was taking certain things for granted.


My system is Logic7 system in full 7.1 in a 3 row SUV. All component speakers.

Two 4” & 1” in dash (my SUV had no center channel so I had to cut my dash to fit). Center channel speakers should be as large as physically possible to fit. Equal in quality as your front door speakers. Powered with similar power.

In my system these are the most important speakers! I can’t stress this enough but, the center channel speakers also should be aimed at the windshield for the widest dispersion. MS-8 crossover @ 200hz – 24dB slope - Focal ES 100K


Front door speakers are in the factory locations. 6.75” midbass bottom of front door, 3” middle of front door and 1” in the sail area. In my opinion putting the speakers in the doors while using a center channel give the widest soundstage as possible. It also cuts down on the reflections off the dash and windshield. MS-8 crossover @ 80hz – 24 dB slope - Focal 165KRX3

(Btw don’t buy these speakers! They sound great but, the crossovers create a nasty turn on pop that Focal and Orca isn’t interested in fixing. Focal recommends 4 amplifier channels feed the crossover because of these speakers extremely low ohm swing. But, somehow the 4 amplifier channels are creating the pop. Disconnect the crossover or the 2 amplifier channels and the pop goes away.)


Rear Door 6.75” in OEM location bottom of rear door and 1” tweeter custom mounted in top of door. The Logic7 works by reversing phase so don't cross these over below 100hz with steep slopes because it will effect your front midbass. If you need to save money this is where you could save, cheaper speakers and/or smaller speakers could be used. MS-8 crossver @ 125hz – 24 dB slope - Focal ES 165K

Behind the 3rd Row in custom pods that are aimed towards the front windshield. . If you need to save money this is where you could save, cheaper speakers and/or smaller speakers could be used. The Logic7 works by reversing phase so don't cross these over below 100hz with steep slopes because it will effect your front midbass. MS-8 crossver @ 200hz – 24dB slope - Focal ES 100K

Two AudioFrog GB10D2 in a ported enclosure and tuned to 30hz. I like ported enclosures because they limit the driver’s excursion as long as you don’t tune them too high. I set the subsonic filter at 20hz – 12dB slope.


Tip #1 - Don’t take for granted your headunits output voltage. I am using a Kenwood Excelon DDX9903S. It is rated at 5v output. When I used a SMD DD+1, it only showed 2.1v with clean signal to 39 out of 40 on the volume.

So in my foolishness I didn’t check what the MS-8 might say. The MS-8 also said the output was clean to 39 but, it was too high. The MS-8 inputs were too high at 34 out of 40. So I was running the MS-8 out of digital headroom at times.

Backed off the Kenwood by using -3 on the volume offset in the Kenwood’s menu. Greatly improved my high volume sound. Btw, I think the DD+1 wasn’t that accurate at reading the low voltage RCAs.


Tip #2 – After you know your maximum volume that the MS-8 is happy with on your headunit, completely disconnect the MS-8 out of the RCA loop and run a RCA from the headunit to your amps. Then set your amp gains. Since I am overdriving most of my speakers and wanted to limit any distortion, I initially set my gains for a 3dB overlap.


Tip #3 – Run speaker polarity test on every speaker in your system! I don’t care if you wired them correctly or not. Some amps reverse the polarity on one channel. Some passive crossovers reverse the polarity too. You can probably use the free AudioControl app and your Phone’s internal speaker for this test. My system was wired correctly but, my polarity was all over the map because of the amps and passive crossovers.
Prior to me verifying all the speakers polarity, my speakers seemed to be flopping about aimlessly. Now my speakers don’t move ½ as much even at full volume.


Tip #4 – Reconnect the MS-8 in the RCA loop and then check each of your speakers output with the MS-8 test. I tried too loud and too soft -35 ended up being my sweet spot for the MS-8 volume. Too loud -30 sounded kinda metallic and -40 too soft the soundstage stage was blurry.

At -35 volume, my mids and highs were around 80dB when checked with my AudioControl SA4140i-SPL from the driver’s seat. You can adjust amp gains down at this point if you have any speakers extremely loud.


Tip #5 – Speakers at their maximum excursions produce their maximum distortion and limit their power handling capabilities. Choose your crossover points accordingly. Just because your midbass is rated to 65hz, doesn’t mean it will sound its best at 65hz or even at 75hz. The idea is to keep the speakers in their sweet spots and to keep the soundstage in front of you.


Tip #6 – The first sweep in every individual seating position is used for speaker location. Disconnect the mids and highs in the front doors for this 1 sweep in every seating location. The MS-8 will then use the midbass’s location. This is step is what finally gave me the sound on the hood effect. (In case you are wondering two pairs of socks doubled (four layers) is not enough to block the sound. I learned this the hard way)


Tip #7 – After running the MS-8 for a couple of test runs, I couldn’t get rid of a major dip that I had at 80hz. Andy suggested changing the phase of my subs. I didn’t think this would help because I had already check everything with my speaker pop polarity tests in Tip #3. I finally did and gained +6dB at 80hz just by flipping the wires.


Tip #8 – Andy says, “MS-8 uses the level of the subwoofer sweep between 50hz and 80hz to set the level of the subwoofer channel prior to applying the EQ.” I have found that I have too much bass around my box tuning region and have had to remove part of it with the MS-8’s graphic EQ. From 63hz and up my RTA looks very good just with the MS-8 auto tune.


Tip #9 - I am using the headunit’s volume control and the MS8 as a black box. So I leave the MS’s volume at a -6 to leave room for any boosting.


In conclusion I would like to say, I am 100% an amateur. These tips were all verified and learned the hard way by me. The MS-8 sounded very good before I learned each of these steps but, it is flat out amazing when you get it right! The singers and instruments truly sound like that are beyond the windshield. The bass even sounds like it is there too!

If I had one complaint, it would be that I lost a little volume but, the MS-8 auto-tune rightfully cuts instead of boosts. So I might adjust the amps gains or turn up the MS-8 volume some.
 

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IMHO it really needs to be reinforced that many of your experiences and tips are specific to the fact that you are running multi-speaker passive XO'd components where the individual drivers are widely physically separated but on a single MS8 channel.

Tip #6 – The first sweep in every individual seating position is used for speaker location. Disconnect the mids and highs in the front doors for this 1 sweep in every seating location. The MS-8 will then use the midbass’s location. This is step is what finally gave me the sound on the hood effect. ...
^This, for example, where in your case the tweeter is in the sail, the mid is halfway down the door and the midbass is low in the door .... all on a single MS8 channel through a passive XO. Obviously the MS8 can't set TA or level discretely for each driver in that configuration.

I'm glad you got things working to your satisfaction, but IMHO the 'missing tip' is for folks to carefully consider their installation design and how that can facilitate or hinder good performance by the MS8 (or any DSP).

For the critical front stage, for example, one is well advised (IMHO) to consider the benefits of trading a discrete front+side+rear setup for a front+rear setup, thereby freeing a pair of channels for discrete TA/level setting for the front. Andy has oft explained that the net gain in perception of separate channels for side & rear ambient fill is very small. Allowing the MS8 to optimize the front stage timing and levels, on the other hand, can be very significant and ease the process of getting a great front (most critical) stage significantly.

Combining closely co-located tweeter/mid combinations (e.g. when both are in the sail) on a single MS8 channel is less problematic, especially if the passive XO (or bi-amping) allows some relative level adjustment between the two after the MS8.

I realize that one is often constrained by OEM speaker locations, but just suggest that the first 'tip' should be recognizing how driver locations relate to timing and level setting requirements and how the MS8 (or any DSP with a finite number of channels) can (or can't) accommodate that in any specific vehicle. All systems involve compromises .... careful consideration of the pros and cons of 'channel allocation' can go a long way toward the ease and degree of success one achieves in the end.

IMHO

Again, congrats on getting your system sounding great for you, that's what matters in the end!
 

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Like Andy pointed out, if the polarity is reversed, it's intentional. Your observation in tip#3 is inaccurate, flipping polarity alone will have no affect on the excursion of a single driver. The speaker will move the same regardless of polarity, it's the acoustic response that may vary. Phase is a relationship between two or more sound sources, so flipping phase on a single speaker will not change how that particular speaker behaves, it will only affect how that speaker interacts with the rest of the speakers. The polarity that the speakers are wired doesn't really matter, it's the acoustic response that matters. Usually you don't need to switch the phase 180 degrees, a few degrees of adjustment via TA is usually the fix, but ultimately it's the acoustic phase that matters, not the electrical polarity.

I'm glad you got everything dialed in the way you want.
 

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Discussion Starter · #5 ·
From what I can remember, my passive crossovers didn't invert the polarity of the tweeters.

It inverted the polarity between the 6.75" that are in the front doors. Bi-amping the 165KRX3 passive crossovers as instructed the 1" & 3" were in positive polarity and the 6.75" were in negative.

I don't know if it was because the crossovers were originally designed by Focal to have 1 input or because they were modified by Orca to have be bi-amped because they dip down to 0.8 ohms around 150hz.
 
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