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Discussion Starter · #1 ·
I've been working on installing a stereo in by car on & off for a while & I seem to not be able to tune the settings to my liking. I was wondering if someone will help me with this setup. I currently don't have a motor in the car & have tried to ask the local car stereo shop guy to come to my house, but no luck & I don't really want to have my car towed there. I also tried to find an audio engineer, but I'm not finding anyone, maybe I'm not looking in the right places to hire one.

My build:
Pioneer DEX-P99RS (31band L/R eq 12db, 8ch RCAs w crossover 6-36db, .25" time increments)
Boston Acoustics Pro 60se 6.5" mids & 1" tweeters
Boston Acoustics pair 10.4 LF sub in a 1.45cu/ft each sealed box running 2Ω
Memphis pair C310D4 sub in a 1.15cu/ft each ported to 28Hz running 1Ω
Rockford Fosgate Power T1693 6x9s
Rockford Fosgate P400-4 74w x 4ch @ 4Ω
Rockford Fosgate P1000-1BD 882w @ 2Ω, 1321w @ 1Ω

Using for tuning:
REW
UMIK
I also have an unknown model RCA adapter mic that I can do time delay measurements.

My current sampling method is 8 point avg:
Mic pointing toward left set of speakers, high point of my head off left ear, while sitting in drivers seat.
Mic pointing toward left set of speakers, low point of my head off left ear, while sitting in drivers seat.
Mic pointing toward right set of speakers, high point of my head off right ear, while sitting in drivers seat.
Mic pointing toward right set of speakers, low point of my head off right ear, while sitting in drivers seat.
Mic pointing toward left set of speakers, high point of my head off left ear, while sitting in passengers seat.
Mic pointing toward left set of speakers, low point of my head off left ear, while sitting in passengers seat.
Mic pointing toward right set of speakers, high point of my head off right ear, while sitting in passengers seat.
Mic pointing toward right set of speakers, low point of my head off right ear, while sitting in passengers seat.

Currently I only have the BA 60se installed in the door(mids) & tweeters mounted 2" deep in the dash mounting holes(shallow mounting the tweeters seem to give problems of sound quality when you turn your head, I assume the dash grading for the sound to come thru was causing this issue). I run these 4 speakers on the 4ch amp. I don't have speakers in the back deck. I have been running the BA 10.4 LF pointing to the rear of the car. My music selection is pop, rock, classic CW, 80s, little bit of Metallica & Techmasters PEB. I listed the other speakers above as other options I have available in spare parts.

I currently am looking for the best quality in sound in 1 sweet spot, might expand in the future(but thought this way would be easier) & I like a lot of bass & I want to keep the cabin speakers in the stock location. My last change was to pull out the Memphis ported subs in favor for the BA sub in a sealed box. The reading I have been doing, sounds like sealed is easier to make accurate, because of potential phase problems of a ported box & my BA subs have a low QTS of .33, which potentially makes them more accurate.

The following test results were produced with the time alignment adjusted to what I think is right settings, no EQ applied & no crossovers on, except tweeter HP filter, to keep from blowing them.

Files:
Radio Specs: Gives you what points I can crossover & slopes available.
House Curve 3: This is the current house curve I strive for at this time for my previous attempt. Probably not useful at this time till we get farther down the road.
Tweet PN: Door speakers pink noise.
Tweet Sweep: Door speakers REW sweep tone.
Mids PN: Door speakers pink noise.
Mids Sweep: Door speakers REW sweep tone.
Sub BA Sealed PN:BA sub pointing to rear of car, pink noise.
Sub BA Sealed Sweep: BA sub pointing to rear of car, sweep.
Sub BA Sealed Pointing Fwd: BA sub pointing to front of car, sweep.
Sub BA Sealed Sideways:BA sub pointing to side of car, sweep.
Sub Memphis Ported PN: Memphis sub pointing to rear of car, sweep, ported pink noise.
Sub Memphis Ported Sweep: Memphis sub pointing to rear of car, sweep, ported, REW sweep tone.
Sub Memphis Sealed Sweep: Memphis sub pointing to rear of car, sweep, sealed, REW sweep tone.

I see that the distortion starts to climb at >450Hz on the BA subs pointing to the rear of car & Mids start to climb at <125Hz & >4400Hz, at 90Hz & 237Hz are also bad, I think the door is raddeling then & tweets at <2500Hz. I don't know how to read the phase chart or if there is a way to fix these issues.


Based on rear facing BA sub:
I would assume I crossover the subs at 400Hz
I would assume I crossover the mids at 160Hz & 5k Hz
I would assume I crossover the tweets at 4K Hz
Probably mess w x-over point on mid & bass in the 80-400 Hz range till I get the curve to look less bumpy.

So 1st off, I assume I need someone to tell me where to crossover & crossover slope rate or anything else you can figure out by looking at the files I've included?

Also, should I be posting the REW sweep or Pink noise or Pink PN results?

Thanks
 

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First, a little convenience matter. It is easier to look at all the curves with them combined into one .mdat file.

Time alignment will only be meaningful at one position in the car. If you are going to bother with it at all, optimize it for the driver position.

Phase information is mainly useful for fine-tuning time alignment. Phase angles should be equal at the crossover frequency at center-of-head at the driver position.

I would simplify the crossover strategy. Crossover at 160 Hz and 4 kHz, eliminating the regions of overlapping frequency coverage. Those overlapping regions will only contribute to unevenness of response through the vehicle. Slopes of 12 dB/oct or steeper would be good. Steeper slopes would be little benefit.
 

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Hi, I have been a car audio installer by profession since 1999. What I see when I read your question is that you may be overcomplicating things. First of all let's talk a out the measurements, unless you have a VERY solid working knowledge of acoustic measurement, performing a measurement in an automotive interior will only serve to confound and confuse. Get the basics down first. I think that having REW available is awesome, but if you were to take your car to me, acoustic measurement software would be used AFTER we maximized the potential of your current components. We could then use the software to HELP determine what areas could be improved with better speakers, amplification, signal processing, etc. I hope that helps at least lend some perspective.
 

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Discussion Starter · #4 · (Edited)
So I got the crossovers set. Here is what it looks like.

Tweeter is crossed over at 4k @ 24db
Mids 4k @ 12db & 160 @12db
Sub 160 @12db
I attached the sweep results.

I experimented after the crossovers were set, reversing 1 tweeter w pink noise, made the sound, sound narrower, as for the mids, I reversed 1 mid & it sounded wider.

I tried reversing 1 mid or both mids while playing music, it seemed to sound a little better on both changes.

Listening to music it sounds ok. Kick drums sound weak as far as punch, most of the time. I hear a high tone annoyance when listening to classic country western male singers, when they try to echo room their voice, too much tweeter. I think they are called top hat, I call them cymbals, some times they sound weak or not full of life, other times they sound ok, but this one is hard to judge as songs tend to vary a lot on how strong they are. Think i'm missing some of the highs, as they don't sound rich all the time. Some songs, the bass sounds a little muddy.

GnR - November Rain - vocals are out front, but instruments are to far back.
GnR - Patience - the whistle intro didn't raise the hair on my arm
Tina & Ike Turner - Proud mary - Ike seems to lack bass in his voice
Madonna - Cherish - Tambourine was loud enough

So what is the next thing I should do?
 

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I'm not surprised that sounds bad - the graph you posted is quite possibly the worst one I've ever seen. 50dB of bass boost?! That would be a landslide worth of 'muddy sound'!

I'd start with the sub crossover point; 160Hz is way too high, especially near-field in a car. Voices will definitely sound off because of that alone. You should consider 80 or even 100Hz instead.

Just out of curiosity... where was the mic, relative to your seating position, when you took that measurement?
 

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I agree with Jim, although your response above 1kHz is quite good. Cut the bass back to a normal level and it will sound much more balanced and much less muddy.

I experimented after the crossovers were set, reversing 1 tweeter w pink noise, made the sound, sound narrower, as for the mids, I reversed 1 mid & it sounded wider.

I tried reversing 1 mid or both mids while playing music, it seemed to sound a little better on both changes.
Do you mean reverse polarity of one tweeter/mid? That shouldn't make it sound better. I would suspect that they were wired backwards to begin with if that is the case.
 

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Discussion Starter · #7 · (Edited)
Ok, just tried 80 & 100Hz, sounds better. I suspect 80 is where I like best out of the 2, but the kick drums are still way lacking. I think voices sound richer. I could reduce the sub lvl a few db if we get the kick drum knocking me out of the car. I do like a bit of bass, but hopefully not retain the muddy to do it.

Richard Marx - Right Here Waiting - bass sweeps sound not to strong when I drop the sub lvl a couple db on the radio.
Led Zepplin - Whole Lotta Love - sounds better at 80Hz wish for more kick drum, then I can drop my peak bass db.



My current sampling method is 8 point avg w umik mic w REW sweeping 1 time per position:
Mic pointing toward left set of speakers, high point of my head off left ear, while sitting in drivers seat.
Mic pointing toward left set of speakers, low point of my head off left ear, while sitting in drivers seat.
Mic pointing toward right set of speakers, high point of my head off right ear, while sitting in drivers seat.
Mic pointing toward right set of speakers, low point of my head off right ear, while sitting in drivers seat.
Mic pointing toward left set of speakers, high point of my head off left ear, while sitting in passengers seat.
Mic pointing toward left set of speakers, low point of my head off left ear, while sitting in passengers seat.
Mic pointing toward right set of speakers, high point of my head off right ear, while sitting in passengers seat.
Mic pointing toward right set of speakers, low point of my head off right ear, while sitting in passengers seat.

I think there is a problem with my test procedure, as the chart above is not repeatable at the higher freq, I just changed the Xover point to sub to mids. The test were 1min apart. My car is parked in a garage, engine not running, 20amp 13.8 power supply holding my Diehard Platinum battery up. I don't experience any power supply noise in the car. My garage lights are LED. Maybe my 1st 2 & last 2 test positions are too close to the door window?
 

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Discussion Starter · #8 ·
I agree with Jim, although your response above 1kHz is quite good. Cut the bass back to a normal level and it will sound much more balanced and much less muddy.

Do you mean reverse polarity of one tweeter/mid? That shouldn't make it sound better. I would suspect that they were wired backwards to begin with if that is the case.
I played pink noise w 1 tweeter reverse polarity, playing both tweeters & all other speakers off. The result of the pink noise sounded like it was more focused to the center of the car. Not reversed was a wider sounding result. When I did this same method, to the only the mids playing, it was the opposite effect.
 

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Discussion Starter · #9 · (Edited)
Ok, I tried to do a repeatability test.

I started by sticking the mic under the headrest on the driver's side, did 4 sweep avg at 256k.
Then I stuck the mic under the headrest on the passenger's side, did 4 sweep avg at 256k.
Then moved back to the driver's seat headrest & started the test over again, getting 3 samples per side.

Mic position pic, red headed screw driver in the mic position for the right side, as an example where I put the mic.


Left side capture


Right side capture


This looks a lot better to me, even though it is not exactly repeatable. I assume this is repeatable enough & I should change my test procedure to just a 4 sample avg on left side, then move the mic to the right side & take another 4 sample avg, then avg the 2 results to 1 for posting?

So here is the avg of the 6 results above.
 

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Discussion Starter · #10 ·
So, I'm bored, got the week off & piddling still. Hope someone helps with the next step I should do?

I tried to do a time alignment, not sure if I'm successful, don't sound much different than being turned off on most songs. I know I need to wait till we get the bugs worked out before TAing, I'll set back to 0, once you guys give me something else to try.

The last thing I started working on tonight is the EQing part. I know I need to wait till we get the bugs worked out before EQing, I'll set back to flat, once you guys give me something else to try. Should I be targeting my curve to ISO226.2003 Curve 70db? I'm trying to get my levels set & this curve is pretty wild to track with my current curve. The following pic shows the blue line (ISO226.2003 70db), brown line my curve & light brown as new calculated curve based on EQ settings. Unfortunately my 31 band EQ wont fit REW, I have to EQ filter it 2 times to get a complete EQ setting. Anyway, my other question is the settings on the right side that says "Individual Max Boost" & "Overall Max Boost", shouldn't "Individual Max Boost" limit the calculations when I press "Optimize Gains" button to 3db per band of EQ? I know we don't want the EQ to fix all my problems, maybe make it a little better though.

 

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Because of the close confines I'm not surprised adjusting delays (TA) didn't really help. For that to be truly beneficial you'd need to be a lot further away from the speakers - there's not enough distance between the drivers and your ears for there to be an audible difference in the time domain.

You'll never get the curve flat, so I wouldn't be too concerned about that. There's nothing in this world that can apply -50dB to any frequency range, and you'll always get a lot of cabin gain because of the small space anyway, so the bass is going to be emphasized regardless.

It may not be advisable to target a pre-determined curve because realistically the only thing that matters is how it sounds to you. In the end you might find a way to lop off 20dB from the bottom octave and decide you don't like it. I think it would be advantageous to tone down the low end as much as you can, but beyond that the measurement is really not all that bad.
 

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Because of the close confines I'm not surprised adjusting delays (TA) didn't really help. For that to be truly beneficial you'd need to be a lot further away from the speakers - there's not enough distance between the drivers and your ears for there to be an audible difference in the time domain.

You'll never get the curve flat, so I wouldn't be too concerned about that. There's nothing in this world that can apply -50dB to any frequency range, and you'll always get a lot of cabin gain because of the small space anyway, so the bass is going to be emphasized regardless.

It may not be advisable to target a pre-determined curve because realistically the only thing that matters is how it sounds to you. In the end you might find a way to lop off 20dB from the bottom octave and decide you don't like it. I think it would be advantageous to tone down the low end as much as you can, but beyond that the measurement is really not all that bad.
x2 :T
I really think you should start with the basics first (level driver to driver volumes aka amplifier gain settings i.e.: how loud the tweet is in relation to the mids, the mid with the sub and so on) crossover slopes (having in mind the performance caracteristics of each driver), and then and only then start worrying with equalization and everything else. My humble opinion at least :bigsmile:

Give us some insight of the upgrades you are doing!
later
dan
 
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