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Discussion Starter · #1 ·
Hello everyone, I have been reading these forums for probably 3-4 hours a day for the past two weeks; first and foremost I would like to thank everyone for creating such a wonderful environment.

I have had very simple aftermarket stereos in several cars, but this is the first time I have actually gone for real quality (however, I wish that I had read a lot BEFORE spending all the money, as I probably could have saved 40%...).

Car: 2012 Chevy Malibu 3LT
HU: Alpine CDE149BT
Amp: Alpine PDX-V9 (4+1 channel, 127x4 / 589x1 watts RMS respectively)
Front: Infiniti Kappa 60.11cs
Rear: Infiniti Reference 6x9 (forget part no.)
Sub: 12W6V3 (sitting in a slanted "generic" enclosure, which is about 20% too large when compared to the sub spec)

The Setup:
-Tweets have been ripped from the A-pillars and velcro'd on-on-axis while I finish my new PVC pods (pulling these from the pillars already made a HUGE difference in sound stage)
-front speakers in stock door location (HPF @ 80Hz 12/dB)
-Rear speakers in the rear deck, don't know where installer aimed the tweets (HPF @ 80Hz / 12dB)
-Sub currently residing about 6" from trunk wall, facing trunk (noticeably better sounding than when close to rear seats) (LPF @ 80Hz / 16dB)

Note: I have not touched gains, and looking at the amp, all gain controls are exactly at 1/3 which makes me think they were not actually set correctly. I know I need to do this; my plan is to use 50 / 100 / and 1kHz tones at -5dB using methods found elsewhere in the forum. Is it worthwhile to use a multimeter instead? I have access to electrical supplies.

I have played around for too many hours with time alignment, and the EQ settings / crossovers. I understand the fundamentals of how a crossover works and what it does, however getting my ears to actually hear a difference is another matter altogether. From the install, HU XOs were all flat, and he set XOs on the amp. I played around with these some, but got tired of climbing into my trunk to set them, so I turned all XOs on the amp OFF and I am now doing it on my HU, however, I honestly can change it all around and really don't hear too much difference.

I found a really alarming problem today. I actually had never tried the MX feature, and on a whim did while I was driving to work today. I was listening to Retrovertigo by Mr. Bungle. The song, and most of the album is very "weak" sounding, and especially Retrovertigo which is my favorite song. I played around with EQ for a long time trying to make it sound better, and just couldn't get that bass guitar to be anything more than a whisper. Then, on the whim I spoke of earlier, I turned on the MX feature, and OH MY GOD that bass popped out and sounded incredible. Sadly, there was real distortion and even when I turned my EQ flat, and used MX, it still distorted and was unlistenable. That's ok, I don't want to use MX, but I DO want to hear that bass!!!!!

Ok guys, I know I am completely rambling. I am at that really terrible point where I know enough about this to be dangerous, but I am sure I have completely exposed myself to be a noob as well. Anyway, I am going to throw out a handful of questions, please, if you have any answers or advice I would be so grateful:

-Is there a SQ / power consideration to be made when using the HU vs amp for xovers?

-Would it be a worthwhile investment to build a custom sub enclosure for my 12W6V3? Ported or Sealed version?

-Should I be treating my front and rear speakers basically the same? They both have a low end of ~50Hz. Should I highpass the front higher? How high? Should I bandpass the rears using my amp xover?

-Why do some songs and albums sound so amazing, and others still sound flat and weak and powerless? It is generally older / more conventional rock music that is "lame" like this. Is older music always like this on nice systems? Or am I just totally FUBARd? I hope I am FUBARd, because then I can fix it.

-I have read that when using EQ, that some people NEVER boost, only cut. To do this, would I just find what I want to boost and then lower everything else? I get so confused with EQ because when I use my RTA (which I am a noob with, but reading tons of tutorials) it seems like even FULL +/-7 adjustments all over the EQ still can barely make the curve look like a house curve.

-More than anything, I am wondering how I can mimic the "MX" function of the alpine HU. I hate black boxes and mystery algorithms, and damnit I want to know how to do it all by myself.

Also, given my system as it currently is, what would the next three or so upgrades be if it were your car? I have 50 sqft of deadener in the mail now, and I am excited to see what it does.


Ok, ok. I have written far too much. Thank you all dearly for the help.

brevous
 

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An amp would allow more power for the speakers and allow them to really open up vs a head-unit( 14 to 22 watts rms vs 100-150 will make a very big difference) as this means they can get a cleaner signal with more wattage, and a custom enclosure for your sub will always be better than even the best prefab box. It sound like you want more midbass, that would require you to treat your doors with sound deadening, and yes most older music is recorded differently in that they come from the days off vinyl which meant the bass couldn't be as loud or the needle would jump out of the groove, so if your going to listen to older music try an find a good remaster. Its okay to boost on an eq its just that every song is different so while one song might sound good at your current settings another could be a distorted clipping mess, so most set theres at flat or at least as close as possible. For me the 3 upgrades would be:1- custom box(although i listen to rap and soul music so mine would be different then your's) 2-sound deadening everywhere(doors, trunk, roof, etc) and I would run the front stage active with that amp and power those 6x9's with the headunit.
 

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Get your gains set correctly before u mess w/ EQ and time alignment. Disconnect the rear speakers, at least temporarily, to see what it does to bass response. Chances are the 6x9s are causing cancellation w/ the bass from the subs.

I would use the HU's crossovers rather than the amp's. Are u sure the sub crossover is 16dB/octave? U probably meant 18dB, but that's still not a very common slope.

U give the power ratings for the amp, but not the ohm ratings. Is that power output into 2 ohms?
 

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"-Is there a SQ / power consideration to be made when using the HU vs amp for xovers?"

Amp crossovers are typically harder to use because you can't get exact with them. If a crossover is labeled (for example) 40hz on one end and 300hz on the other..where would you put it for 80hz? This isn't much of a problem if you are dialing in the crossover point to match the rest of the speakers because you can just fiddle with it 'til it sounds good, but what if you need precision in trying several combinations based on RTA (or ear) measurements? More on power later.

"-Would it be a worthwhile investment to build a custom sub enclosure for my 12W6V3? Ported or Sealed version?"

Maybe. If in doubt on what type of enclosure to use, larger sealed boxes are pretty much a catchall for any sub, and that's what you have already. I would work on other areas first because a lack of bass (which you seem to have) can be the result of crossover, EQ, and bass-midbass integration issues rather than the enclosure itself. You'll probably find it useful to start off tuning without the sub on at all, and when you get done setting the rest of the speakers up bring the sub in last to integrate it with everything else.

"-Should I be treating my front and rear speakers basically the same? They both have a low end of ~50Hz. Should I highpass the front higher? How high? Should I bandpass the rears using my amp xover?"

You should really seal them up and damp the areas they attach to. See the numerous "sealing/treating my doors" threads for more info. Although you say they have a low end of 50hz, it's not likely you are getting any kind of volume down that low right now. That's why you have to EQ the hell out of the low end to get any bass/midbass out of them, and (probably) why they sound horrible when you do so. On that note: any boost of 3dB requires doubling amplifier power to do so. If you take a normal, flat signal and lets say you have 15 watts driving the speaker [side note: I'm also assuming a flat impedance response, which is not ever found in the real world unless you get into zobel networks or ribbon/planar drivers, but that's another topic]. Add a boost at 50hz of 6dB - now you need the amp to supply (15*2*2) 60 watts to effectively add that boost. With the power from the headunit, you can easily see that you just don't have it, and that electronic boost just turns into a flattened crushed waveform (clipping) instead of actual usable power.

"-Why do some songs and albums sound so amazing, and others still sound flat and weak and powerless? It is generally older / more conventional rock music that is "lame" like this. Is older music always like this on nice systems? Or am I just totally FUBARd? I hope I am FUBARd, because then I can fix it."

As was already said, lots of music just isn't recorded "well" for the way you like it. But I'll say this: the better I get at tuning, the better all music sounds. Having enough power on tap to compensate for more quietly recorded albums is always a good thing.

"-I have read that when using EQ, that some people NEVER boost, only cut. To do this, would I just find what I want to boost and then lower everything else? I get so confused with EQ because when I use my RTA (which I am a noob with, but reading tons of tutorials) it seems like even FULL +/-7 adjustments all over the EQ still can barely make the curve look like a house curve."

That gets back to what I was saying above. Adding a boost isn't necessarily a bad thing if your amp (and speaker) can handle it. The problem with boosting is how that boost translates acoustically into what we hear. Because of the acoustic character of the car, and where your head is sitting within the space of the car, there will be certain frequencies that cancel out right in your head's position and will sound weaker. Trying to add an electronic boost through EQ will make the speaker(s) play harder in that frequency, but you won't actually hear an acoustical increase in energy. That's why it's better to EQ the areas around the dip down to compensate and form a smoother frequency response curve. Our ears aren't very sensitive to wide dips and peaks, but are VERY sensitive to sharp spikes in the frequency response. On that note: there's no way to overcome this "natural" cancellation other than adjusting something in the acoustic environment (by treating your doors, moving the speaker location, etc.). If you have a dip at 100hz you want to fix and you cut everything else besides 100hz (because cutting is OK, right?), but then you compensate for this by turning up the volume, you're doing the exact same thing as simply boosting at 100hz.

"-More than anything, I am wondering how I can mimic the "MX" function of the alpine HU. I hate black boxes and mystery algorithms, and damnit I want to know how to do it all by myself."

I googled it and it looks like a basic EQ circuit. Boost a bit in the bass, boosts a bit in the treble. I'm of the opinion that people who say to "never use the "loud" button!" are wrong. It's EQ, just the kind of EQ you can't set yourself. If it sounds better, doesn't clip the preamp signal to your amp* and you have the power to back it up and speakers that can handle the power there's nothing inherently wrong with it.

*Looks like some people have already tested if the MX clips the signal. Levels 1 and 2 seem to be OK, level 3 definitely adds some clipping. Alpine mx - CarAudioForum.com

"Also, given my system as it currently is, what would the next three or so upgrades be if it were your car? I have 50 sqft of deadener in the mail now, and I am excited to see what it does."

Exactly what you are doing. Treat the speakers first to get them to sound their best.
 

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Once you have your amps/gains set properly, I have something for you to try. I have very similar amp power to you and had a bass issue with my system.

As was mentioned, use the HU crossover and I'd set slopes to 12/db for everything to start out with. I use 80 HP/LPF, you can experiment with this later. Make sure subwoofer system is set to 2, check for your bass response with phase at 0 or 180 degrees. If one is better than the other keep that one. Make sure subwoofer level is 15/15.

Leave the EQ and MX settings alone, until you figure out whats going on with the sub, keep those off/flat.

In the crossover on the HU, go to front and set the level to a negative value, do the same thing in the rear, keep the subwoofer at 0.

What I found in my setup with a PDX-F4 and PDX-M6 (100W x4 / 600W mono) was that when they were both set to clip at the same volume level, my full range was sending so much power to my system that I couldn't even hardly hear the sub, my 6x9's were putting out damn near the amount of bass that my subs were.

I used the crossover to blend my amps without having to touch the gains. Now it sounds fantastic and even better I can adjust it on the fly from the HU.

I asked in another thread for an explanation but never received a response. Unless my issue is just a fluke of the cabin in my vehicle type, it would be worth trying out in your system.
 

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Discussion Starter · #6 ·
Wow you guys, thanks for the great input. You have helped to clear a lot up for me. I guess I really need to get all the basics done first (correct gain, levels, deadening, etc.) before I start doing anything fancy.

Is that power output into 2 ohms?
Yes, it is.

Oh boy, started this reply about an hour ago and now I am in real deep regarding door sealing.

Also, may be a silly question (and I DID google...) but what exactly is a speaker baffle? I see some places saying it is just the "frame" that holds the speaker, some make it seem like the baffle is just the front "ring". Anyway, I am confused.

Really wish I had a friend who knew about all this, but that's what you guys are for!

Thanks again, it is much appreciated :)
 

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The baffle is whatever the speaker attaches to, and more precisely it's what separates the front wave of the speaker from the back wave. Sometimes an adapter piece (like an MDF ring) is referred to as a baffle, sometimes the entire plane where the speaker mounts is called the baffle. ex: "I'm using a 3/4 MDF baffle to attach my midbass to the door"; "With the speaker mounted on the door, I'm using the stock door panel as a baffle"

The three things it needs to do are: (1) Hold the speaker firmly in place, and not vibrate with the movement of the speaker cone, (2) Not resonate sympathetically with the acoustic output of the speaker ("ringing"), and (3) Completely separate the rear wave of the speaker from the front wave (excluding vented designs).
 

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Sounds like most of your questions are answered in detail. So I don't have any thing to add really lol, but just spend a bit of time of your front speakers. These are 70% on what you hear, so getting them right is a must for a good sound stage and reproduction. Definitely go with a custom built enclosure for that sub it will make a huge difference between a prefab box or a wrong size random box that is too big or too small. I didn't recall seeing sound deadening in the posts, I could be wrong, but, I would definitely sound deaden the front doors around the mid bass, and if u can in the back around the back near the sub, you don't want any rattling that will mess up your sound and just sound annoying.
Any other issues or questions/thoughts you have?
 
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