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Discussion Starter #1
Welcome to Version 2 of the SQ Car Audio thread!


The last thread got buried and full of information. It's a bit daunting to sort through, so I've created a new one to make it a whole lot easier and to consolidate some of this information. Given the sheer number of questions I get regarding this, I figured I'd create a thread to answer them off the bat.

My mission here is to make competition-level sound quality feasible and affordable so you don't spend the thousands of dollars going through parts only to come back to this point. Read this thread, and you can build on my experience.


Getting Started
To start, you'll want a good idea of basic audio principles so you know what I'm talking about throughout this thread. For that purpose, I've created four basic Audio 101 "lectures" on my website, which you can find in the link below. Start from the bottom. If you have questions, post them here. Don't even bother thinking about SQ car audio until you've read these articles.

Audio 101 - The Xtreme Revolution


Expectations
I'm sure some of you came here thinking "The sound system in my Cruze sucks, what can I do to make it better? I want some great sound!" I hear that a lot, and I have an inbox full of these types of questions. Before we proceed, there are things I expect of you. If you cannot meet these expectations, you shouldn't be here.


  1. Cost. As a starting point, you should expect to spend $1000 if you want a good set of front speakers with MDF baffles, a proper install with door and trunk treatment, good wiring, and a good SQ subwoofer in a custom box. If don't have at least $1000 or don't want to spend that much, come back when you have accepted the cost of this endeavor. This applies to total installs, not to just a single subwoofer. Some of you will probably say, "but I can do it for so much cheaper than that!" Really? With a passive crossover front component set, a single 8" subwoofer, custom box, two amplifiers, sound deadening, and an AA-GM44 harness, you're right around $930, and we haven't begun to talk about wiring. If you can build the box yourself, you can save some money. Otherwise, I build subwoofer boxes and MDF speaker baffles at what most consider to be a very good price.
  2. Time. If you want a system installed within a week because you just got your tax return, your bonus, or birthday money and can't contain yourself, don't waste my time. It will take you time to choose the parts that are right for you. It will take you time to learn why they were chosen, and why you shouldn't have bought the ones on the shelf at Best Buy. Since you will most likely be installing this yourself (let's be realistic, most shops do shoddy work by my standards), you will need time for that as well. We have some members on this board who can perform high quality installs should you really not want to pull your own trim panels.
  3. Effort. You need to learn at least the basics of audio. If you don't want to put any effort in, don't expect me to help you. I know this doesn't apply to most of you out there, but I'm saying it as a fair warning to anyone who thinks they can have their hand held throughout the entire process. I'm making tools available to you so that you can learn, have true appreciation for what's going on, and put together an excellent system.
  4. Patience. This ties in the last two points, but it deserves its own point. If you order a box and baffles from me, expect to wait a while as I've never yet had a day where I didn't have a box in progress. If it takes me 2 months to get everything done, chalk that up as part of the cost of getting a competition-ready custom made subwoofer box built for cheap. If you find yourself not understanding how something works or how to do something on your car, don't get frustrated. Ask questions, and wait for an answer. Keep in mind that we all have lives outside this forum.


In my next post, we'll move straight to system recommendations.
 

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Discussion Starter #2 (Edited)
I figured I'd create a post to keep the updated tunes available for anyone who wants to run a high-end install with a miniDSP. Yes, this is hours upon hours of tuning for free. All you need to do is buy the parts, flash the tune, and win competitions. It's really that easy. Feel free to use this thread to write reviews of these tunes.

High Value: Silver Flute/Vifa
Silver Flute W17RC38-04 6.5" 4 Ohm
Vifa BC25SC06-04

Mid Level: Dayton RS180/Seas Presitge
Dayton Audio RS180-4 7" Reference Woofer 4 Ohm
Seas Prestige 27TFFN/G


Crossover: miniDSP
miniDSP 2x4 | miniDSP
miniDC Isolator | miniDSP
Audio plug-ins summary table | miniDSP (2 way advanced)

Tunes are attached for the combinations above.
 

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Discussion Starter #3
I wrote a few articles recently for someone else on system design that I'll include here to help make sense of why I chose these components.

We'll split this up into two parts; bass and front stage. I can go into great length regarding subwoofers, so we'll just start with the front stage first.

Cookie cutter "component sets" all fail. Every single one of them is a complete and utter acoustic failure. Every component set that comes in a 2-way or 3-way system with a passive crossover box intended to be glued, mounted, or glassed into place or some pods in your car and run off of an amplifier are complete garbage in that alignment, no matter if they're $100 or $1000. The reasons are the following:

1. Every car is different. There is no "one size fits all" out of the box component set that will sound good in every car.
2. Passive crossovers suck. Having designed them from scratch with simulation software and precise measurements in home theater, I can say they are great in a home environment when designed well, but junk in a car environment.
3. A speaker will sound entirely different on one side of the car as it will on the other side, relative to the driver's listening position. A component set with a passive crossover cannot compensate for that.

You can buy a 31-band graphic equalizer and your tuning efforts will frustrate you to no end because all you'll be able to do is tune the sum of the entire system. You will be mislead by the misunderstanding of the situation. You will think "but I have the same drivers on the left and right side, so why can't I just tune them all together?" Like I said, your midbass door speakers will sound different on the driver side compared to the passenger side relative to the listening position, as will your tweeters.

In order to have a proper sounding system, you need to be able to tune each individual driver independently. Your goal is to get a flat frequency response, so that when you play music, it will sound as close to the original recording as possible. Using a measurement microphone and an RTA (real-time analyzer) program such as SynRTA, you will make changes to correct the anomalies of the specific vehicle you're in. To illustrate what this would look like, here's the parametric EQ response I needed to tune in my Cruze for the tweeters.

Driver's side tweeter:


Passenger's side tweeter:


You'll notice that in order to get a flat frequency response, I had to tune both of them differently. They each had their own particular anomalies. Here's what the tweeter pillars look like:



There's an identical one on the other side of the car that I didn't take a picture of, but you'll see that they basically fire out toward the other side of the car, not diagonally or toward any particular listener.

I pointed out a few particular areas of interest with arrows so you can see some of the differences. Keep in mind here that every 3db change represents a doubling or halving in output, so the effects are really quite significant. The way that the pillar, windshield, dash, and window reflect the tweeter's sound on the passenger side will cause it to sound entirely different from the driver side, and this needs to be measured from the driver's listening positioned and tuned accordingly. This same behavior also applies to the door speakers.

To add to all this, even a 31-band equalizer is horribly unsuitable for this kind of anomaly correction. You need parametric equalizer bands, you need to be able to tune each driver individually with them, and you need lots of them if you want excellent results. Sounds expensive, right? If your head is stuck in car audio brands, this kind of equipment will cost you several hundred if not over $1-2k. Keep reading...
 

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Discussion Starter #4 (Edited)
Moving on, we have the issue of time alignment that needs to be addressed. This picture from crutchfield outlines the issue very clearly.



Ignore the subwoofers in the rear for the time being and pay attention to the driver position relative to the front tweeters and front door speakers. In order for sound to be uniform, all speakers have to be equidistant from the driver's ears. In a car, they simply are not. Depending on the exact design of the speakers, they will all be different distances from you. This is something that a component set cannot accomodate for you, but is extremely important.

In my Cruze, here are the speakers and their distance to my ears, from farthest to closest:
Passenger midbass
Passenger tweeter
Driver midbass
Driver tweeter

What we have, in effect, speakers that, with a component set, would all play sounds at the exact same time. However, the sounds will reach your ears at different times due to different distances to your ears. This delay causes music to sound blurred and unnatural, and makes it even more difficult to tune. Since we cannot speed up how quickly the speakers further away from us produce sound, we need to delay those closer to us so that they wait for the farther away speakers to produce sound.

Let me tie this all in with some real numbers.

Because my tweeter is the closest driver to me, it needs the largest delay to "sound" as far away as the passenger midbass. In order to simulate an additional distance, I need to measure the distance from my ears to each individual speaker, then adjust the time delay to simulate that distance. Here are the distances that need compensation for my Cruze:

Driver Tweeter: Delay by 0.427 meters; 1.24 milliseconds
Driver Midbass: Delay by 0.334 meters; 1.00 millisecond
Passenger Tweeter: Delay by 0.124 meters; 0.36 milliseconds
Passeinger Midbass: Farthest away; no delay needed.

When you have all of those dialed in, the music will sound like it's coming from directly in front of you. You will not hear individual speakers plying music anymore; you will just hear a single music source that sounds like it's coming from the dash immediately in front of you. You are probably thinking to yourself; "Seriously? One millisecond will make a big difference?" The answer is yes. It makes a massive difference. Once you have these settings dialed in, I can adjust those delays by 0.02 milliseconds at a time, and a mere .1 millisecond will cause the source of the music to shift from immediately in front of you, to a physical 1 foot to the right. I can effectively "pan" the sound source left and right across the dash by adjusting the time alignment of specific drivers.

Again, this is not something you can do with a cookie cutter component set. It requires you to make adjustments to your specific car, which will vary from my car or that of a friend. Understanding the concepts allows you to turn tuning into a simple matter of learning how to use the specific hardware.

So, you're still probably thinking...****. This is going to be really expensive, won't it...

Keep reading.
 

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Discussion Starter #5 (Edited)
So far, we talked about frequency response and the importance of tuning drivers individually, and we talked about the importance and purpose for time alignment. In this post, I'll go over crossover points. My article on my site went into reasonable detail regarding what crossovers are and how active and passive crossovers work.

Since we aren't going to be buying a component set with a passive crossover bundled and will instead be buying raw drivers, we need to figure out what our crossover points should be. Since raw drivers rarely list an advised crossover point and slope, how do we figure this out?

Measurements. For this part, we use software called ARTA to measure harmonic distortion. Harmonic distortion affects a significantly large frequency range and will not come up in a frequency response measurement. The most offensive to our ears is 3rd order harmonic distortion. I can help anyone learn how to use this software since there's a small learning curve, but basically, you use a measurement microphone to get the reading you need. We can just skip ahead to the measurements you'll get. What we do is start with a low crossover point and take a measurement.

For the tweeter, we need a high-pass crossover filter, which means we need to let the high-frequencies pass through the filters and let all frequencies below the filter be blocked out. We naturally don't want our tweeters to be playing bass, but we want them to play as low as possible to lift our sound stage above and away from our feet. The purpose of harmonic distortion measurements is to determine just how low we can play them before they start to sound fatigued and strained, and the best way to do that is to measure them.

Here are some measurements I took while tuning a friend's Scion tC. In Red, I outlined the harmonic distortion (gray line). In blue, I outlined a particularly harsh frequency response peak that we either need to tune out with a parametric EQ, or filter out with a crossover. In this particular case, you'll see that peak reducing as we raise the crossover frequency.

We start our measurement at 800Hz. This way, we get a good idea of the big picture and have a starting point. I would advise no lower than 650Hz for dome tweeters. Note the large peaks in harmonic distortion and frequency response.


Going to 1500Hz reduced both peaks, but they're still too high for comfort, and I know better than to think this tweeter can do 1500Hz. Something also seemed to mask the distortion in the first peak at 2500Hz, so we'll just keep going.


Up to 2000Hz now. Our frequency response peak is more manageable, and we are seeing a more accurate picture of harmonic distortion. Our biggest concern at this point is the HD peak at 2800Hz.


Let's go to 2250Hz. Looking better!


At 2350Hz, we see a reduction in both Harmonic Distortion peaks!


At 2500Hz, we don't see much of a consequential change.


At 2750Hz, we see the first HD peak at around 2800Hz being reduced, but only because all output is being reduced now, not because our crossover point is causing harmonic distortion.


At 3000Hz, we see a notable reduction in total Harmonic Distortion, but we've now lost a lot of sound stage due to such a high crossover point. This is what you'd typically find in a component set's passive crossover.


Let's try to tie this together.

From 800Hz on up to 2250Hz, we see harmonic distortion at high levels, with peaks at ~2800Hz and ~4000Hz. As we increase the crossover point, we see those harmonic distortion peaks reducing, even though we are not filtering those specific frequencies! The intention of these charts and this post is to point out that we are getting distortion at 2800Hz and 4000Hz simply due to us forcing the tweeter to play lower than 2000Hz. To put it simply, we are playing the tweeter too low out of its designed range, and that is screwing up the rest of the tweeter's range.

It is typically assumed that if we have a tweeter that can play down to a given frequency such as 2000Hz, that if we cross it down to 1500Hz to have it play 1500-2000Hz, that only that range would be affected. It is very important to realize that in addition to hearing distortion at 1500-2000Hz in this hypothetical scenario, we will also be creating distortion above 2000Hz.

In this particular case, any crossover point above 2350Hz does not affect our harmonic distortion in this way, and every frequency below 2250Hz does create additional harmonic distortion. As a result, for this particular tweeter, I would recommend a crossover point of 2250-2350Hz, but no lower. This allows us to fully utilize the tweeter's capabilities without creating unwanted distortion.
 

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Discussion Starter #6
The above post probably intimidated you a bit, and that's to be expected. It's a lot to take in, and there's a bit of a learning curve to taking those kinds of measurements. The intention here it so point out how a crossover point is chosen. Fortunately, I've already measured some of these tweeters, so I can tell you precisely what crossover point to use for them, which removes a lot of work on your part, and leaves you to take some of the easier measurements on your own.

Let's tie all of this in. To get a good front sound stage, we need:

1. Frequency response measurements on each individual driver
2. Time alignment adjustments on each individual driver
3. Crossover slopes picked out by precise harmonic distortion measurements

How do we do this? miniDSP.

This little circuit board does all of the above, for $100.
MiniDSP kit | MiniDSP

If you want it in a fancy looking case, you can have that too for an extra $25
MiniDSP 2x4 | MiniDSP

You'll need to buy the miniDC to filter power:
miniDC Isolator | MiniDSP

And you'll need the 2-way advanced plugin:
2way Advanced | MiniDSP

All in all, you're looking at around $150-$175 shipped for the whole setup, allowing you to configure a competition-winning sound stage. No external active crossover with a car audio label can touch this. $1000 Pioneer head units can't touch this.

Links are provided in the 2nd post.

The Silver Flutes and Vifa together with the miniDSP will run you under $300 shipped, and you'll need a 4-channel amp to power them (one channel of amplifier per driver).
 

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You dont know anything xtreme...nothing, you know nothing.I have facts to prove all of this wrong,all of it.Proving you know nothing!Comon you need a new headunit to make this all work.











:bowing::sarcasm::nicetopic:
 

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This is what you have come to realize from our conversation !
Understanding All
 

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I just checked their site and it seems prices have come down? MiniDSP 2x4 with box is $105 + MiniDC $12 + Plugin $10 = $127. That is pretty cheap and very flexible tuning... wow.
Yeah I looked as well $80 with out cover . Not bad at all


Sent from AutoGuide.com App
 

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I have a question for extreme revolution. I have a 2014 cruze with mylink/navi/touch screen. If I was to run your recommended active set up but with a tc sound epic 10 in one of your fiberglass sub boxes instead of the ID sub would it sound better or worse in your opinion? also what amp would you recommend for that set up? Is there a 5 channel you would recommend so I only need one amp so less trunk space would be lost? also what would you run in back seat area just the silver flutes? Thank you for your time.
 

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Discussion Starter #13
I have a question for extreme revolution. I have a 2014 cruze with mylink/navi/touch screen. If I was to run your recommended active set up but with a tc sound epic 10 in one of your fiberglass sub boxes instead of the ID sub would it sound better or worse in your opinion? also what amp would you recommend for that set up? Is there a 5 channel you would recommend so I only need one amp so less trunk space would be lost? also what would you run in back seat area just the silver flutes? Thank you for your time.
The TC Sounds Epic 10 would work just fine in the fiberglass box. It would sound similar but not quite as loud as the ID sub would. Frankly I'm not sure if I can continue to recommend the ID subs anymore as the V3 lineup is discontinued now and the V4 lineup looks different. The appearance is the same, but the specs changed and I don't like what they changed to. They are no longer "small box-friendly" subs.

As for the amp, any CEA certified 5-channel amp would do. Just get something that provides 500W of power at the impedance you want to run for the TC sub. The Epic 10 can be run at 1 or 4 ohms. I'd look for 350-500W RMS.

I would not run anything in the back seat. Disconnect the factory speakers and just run a front sound stage. Worry about the back only if you have to transport other people on a daily basis. Otherwise, it just screws everything up.

It all really depends on what your budget is.
 

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Having carefully analyzed and modeled the new V4 Image Dynamics subwoofers, I cannot recommend any of them. Not a single one. Not even the new IDMax15. Qts has nearly doubled across the board as a result of a nearly doubling in suspension stiffness. This is a huge deviation from what the V1, V2, and V3 Image Dynamics subwoofers were all about.

As a result, my "IDQ Replacement" will be the TC Sounds Epic 10 and Epic 12 subwoofers. I have yet to determine what to recommend in place of the IDMax.
 

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For the time being, you can still readily find v.3 variations.
I'd continue recommending them until stock starts to dwindle.
 

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I wrote a few articles recently for someone else on system design that I'll include here to help make sense of why I chose these components.

We'll split this up into two parts; bass and front stage. I can go into great length regarding subwoofers, so we'll just start with the front stage first.

Cookie cutter "component sets" all fail. Every single one of them is a complete and utter acoustic failure. Every component set that comes in a 2-way or 3-way system with a passive crossover box intended to be glued, mounted, or glassed into place or some pods in your car and run off of an amplifier are complete garbage in that alignment, no matter if they're $100 or $1000. The reasons are the following:

1. Every car is different. There is no "one size fits all" out of the box component set that will sound good in every car.
2. Passive crossovers suck. Having designed them from scratch with simulation software and precise measurements in home theater, I can say they are great in a home environment when designed well, but junk in a car environment.
3. A speaker will sound entirely different on one side of the car as it will on the other side, relative to the driver's listening position. A component set with a passive crossover cannot compensate for that.

You can buy a 31-band graphic equalizer and your tuning efforts will frustrate you to no end because all you'll be able to do is tune the sum of the entire system. You will be mislead by the misunderstanding of the situation. You will think "but I have the same drivers on the left and right side, so why can't I just tune them all together?" Like I said, your midbass door speakers will sound different on the driver side compared to the passenger side relative to the listening position, as will your tweeters.

In order to have a proper sounding system, you need to be able to tune each individual driver independently. Your goal is to get a flat frequency response, so that when you play music, it will sound as close to the original recording as possible. Using a measurement microphone and an RTA (real-time analyzer) program such as SynRTA, you will make changes to correct the anomalies of the specific vehicle you're in. To illustrate what this would look like, here's the parametric EQ response I needed to tune in my Cruze for the tweeters.

Driver's side tweeter:


Passenger's side tweeter:


You'll notice that in order to get a flat frequency response, I had to tune both of them differently. They each had their own particular anomalies. Here's what the tweeter pillars look like:



There's an identical one on the other side of the car that I didn't take a picture of, but you'll see that they basically fire out toward the other side of the car, not diagonally or toward any particular listener.

I pointed out a few particular areas of interest with arrows so you can see some of the differences. Keep in mind here that every 3db change represents a doubling or halving in output, so the effects are really quite significant. The way that the pillar, windshield, dash, and window reflect the tweeter's sound on the passenger side will cause it to sound entirely different from the driver side, and this needs to be measured from the driver's listening positioned and tuned accordingly. This same behavior also applies to the door speakers.

To add to all this, even a 31-band equalizer is horribly unsuitable for this kind of anomaly correction. You need parametric equalizer bands, you need to be able to tune each driver individually with them, and you need lots of them if you want excellent results. Sounds expensive, right? If your head is stuck in car audio brands, this kind of equipment will cost you several hundred if not over $1-2k. Keep reading...
Please explain something to me here. I am from the old school days where you replaced the HD Unit with a high end one that has higher voltage and some with burr brown chipsets. The mindsp not only gives you tons of tuning capabilities but also makes the fac HD unit signal better quality, am I correct??
 

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Please explain something to me here. I am from the old school days where you replaced the HD Unit with a high end one that has higher voltage and some with burr brown chipsets. The mindsp not only gives you tons of tuning capabilities but also makes the fac HD unit signal better quality, am I correct??
The factory head unit isn't the greatest thing in the world, but it's certainly not bad. You can get excellent results with the right tuning by using the signal coming out of the head unit. The voltage will depend on your line out converter. The miniDSP allows you to keep your factory head unit and focus on the sound quality and tuning aspect of it. This greatly improves the tuning capabilities and design options.

The reason why I don't recommend replacing the head unit is that you need to spending in excess of $1500 on the rest of the parts in order for the head unit to do you any good. The value of replacing the head unit is very small, as you will be spending at minimum $200 on a good deck, in addition to another $150+ in factory integration modules, plus a dash kit. At the end of the day, you still won't have the power and tuning capabilities of the miniDSP. Even if you go with a $800-$1000 deck, you won't have that kind of power. That money is better spent elsewhere.
 

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Discussion Starter #20
I think I'm going to do the front active midlevel kit you have in the 2nd post. I have this amp from my old car...would it work with the Dayton RS180/Seas Presitge speakers?


Pioneer GM-5400T (GM5400T) 760W 2-Channel GM Car Amplifier


Also, do the Seas Prestige tweeters fit in the A pillar? I can't tell if you built a different tweeter cover in this picture or what's going on there...

I have that tune because I installed those parts in Smurfenstein's car. The tweeters will fit just fine with some hot glue. That tweeter cover was for my MDT-44 drivers because those have a dome that protrudes past the mounting plane and no cover. You don't need to do that with the Seas Prestige.

That amp will power the RS-180s just fine. You will need another 2-channel amp for the tweeters but you don't need anything really powerful. You'll never give them over 15W RMS. You need 4 total channels of amplification.

Sent from mobile.
 
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