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Audio Knowledge

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First one can be a somewhat waste of time, but different perspectives never hurt. Just gotta make sure the logic isn't circle logic or based on something untrue.

Second one, we have one in these boards here.

Third one:

Tuning of a ported subwoofer box is determined by a combination of port area, port length, and net volume of the subwoofer box.
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Completely ignores that the sub's T/S specs determine how effective the box is and if the port is even useful for the sub. (in otherwords how it reacts to power at frequency in a box at varying sound levels)

Personally if 30-40 Hz is three times louder than 20-30 Hz or 40-100 Hz then it sounds like crap. Peaky subs do not make for good sound quality. They do however make for great SPL subs. The most impressive systems are the ones that bump equally at all frequencies yet so clean you can hardly notice its loud minus the fact it affects your breathing, shakes your clothes and the car is being shaken apart. :)

Fourth link, thats a good one! :D
 
this is the audio section.

Note how this thread is still just one page long?

But can you still edit posts in a locked thread?

If so, i agree with that motion.
 


So if anybody pays attention to me...I'm always looking for perfection within imperfection; car audio. However, I like to do it with a stroke of simplicity that's easy on the eyes and easy on the wallet.

Anyways, problems with my bass response has led me to more tuning issues. Prior to my recent change in install parameters I was crossing rather high...playing with anything between 80hz and 160hz. I was able to dial it in MOSTLY because I have Time Alignement built into my head unit and I also have stereo output available for subs that coincide with LP filters.

Anyways, the install change forced me to take a different approach. Now I only have a single sub so processing can't really help anything with a mono output. Therefore, I have switched my LP on the sub to 63hz w/36 decibel slope and the mids have an HP @ 63hz w/24db slopes. I used my parametric EQ to add +1 at 80hz with a Q of 3. What is Parametric EQ? <----**CLICK HERE**



Here's a decent post on why my stereo is setup the way it is now....

Bass - Punch in the front, not in the back<------**CLICK HERE**

If you want frontal presentation on your sub, you'll have to break some mindsets and ignore some forum folklore. Here's why.

1. Xover points: A decent pair of ears will locate source of sound above 70hz (appx). 120hz as suggested is way too high. So you're looking at crossing your sub and mids in the 50-63hz range. Put the sub and mid on the steepest slopes that you have. The sub because you want your mids stronger at 80hz and steep slopes on the mids cause they are rolling off sharply anyways around 50hz.

2. Blending: The next step is to blend your sub bass with your mid bass. 50 hz from your sub will be much louder than from your typical 6.5" mid. You want the flow back and forth between your mid bass and sub to be smooth. i typically level match from my eq +/-1 octave from the xover point. So I level match the 30hz-125hz range to get the right blend.

3. Time Alignment: Use your time alignment to connect your drivers. The sub with the mids and the tweets with the mids. You want to hear the tweets last, that will pull up your entire stage.

4. Kidney punch = Chest thump: Part of getting the sub presentation upfront is accepting that it won't be as loud as the kidney punch option. Balance is what you're aiming for. Balance for L/R if you can and across the sound ranges. One sound, unisource, sound totally disconnected from the drivers. What you lose as impact from the sub you make up by getting a solid impact across 20-20khz.

Hope that helps.
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You should measure the drivers individually to figure out what their installed slopes are.

Makes it easier than guessing what to set the crossover orders at.

Other than that... Thanks for seeing the light :p
 
Well...the bigger issue is I can't run stereo subs anymore. It was more like a 3-way with 12" speakers :)

Now that I'm limited to just one sub I had to change my approach. Of course none of this works WITHOUT a processor because I still have 4 sets of speakers time aligned. The sub is left out of that now but I still had a couple of microseconds and it tightens up the response. I'm not sure if it's due to cancellation of distortion or what...
 
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Here's another response I found....

Patrick Bateman said:


Autosound 2000 solved this one twenty years ago. Save yourself some heartache and pay the three bucks for their guide to doing this. (Google "david navone autosound2000 upfront bass etc")

In a nutshell, you want to get a few things right:

  • As Lycan noted, the "impact" of the bass is a lot higher than what you'd think. If you screw up the midbass range, you'll never get the "upfront bass" illusion.
  • When it comes to subwoofers, second and third harmonic distortion is The Devil. For instance, if a big bass note hits at 40hz, the 2nd harmonic is at 80hz and the third is at 120hz. THERE'S NO ELECTRONIC METHOD TO REMOVE DISTORTION. That's the critical thing to the illusion of upfront bass. YOU CAN'T FIX IT WITH ELECTRONICS. Anyone who tells you otherwise is trying to sell you something, or simply doesn't know better.

Once you have those two points down, you'll start to realize why some systems seem like the bass is up front at low volume, but when you crank it up, it goes to hell. That's subwoofer distortion rearing it's ugly head.

Once you have that figured out, you just pull out the usual tricks to fix it:

  • Distortion goes up with excursion. Therefor, if you can keep excursion under control, you can keep distortion under control. (There's a reason that Richard Clark used dual 15s. Lots of cone area = low excursion = bass up front.
  • Infransonic filters can lower distortion dramatically
  • Unconventional box designs can lower distortion dramatically. Tapped horns, horns, ported boxes and bandpass boxes aren't used half as much as they should be. YES they're difficult, but they're distortion-killers when designed properly. Designed improperly, they can really suck.
  • Push-pull mounting is free and reduces second harmonic distortion dramatically.
  • The best way to reduction distortion is to measure it, and deal with it accordingly. I'm always kind of amazed by how difficult it is to pinpoint distortion by ear.
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