"Q" of a sub .707?

[I800C0LLECT]

Now a while back I paid attention to this in order to find how the speaker's response would work with the cabin gain. I found out that depending second and third harmonic distortions I either liked it(clean) or I didn't(muddy). A lot of that had to do with the back wave from the subs which directly related to their position in my trunk.

Anyways, here's a post that basically says go to hell Mostly because the Qtc of a speaker can change as much as 10% just because of temperatures or other factors. Matter of fact, it's changing as the speaker plays.

DIYMA.com - View Single Post - Q alignment for sealed subs - which do you prefer?

 

[matt5112]

build a better midbass foundation then you could cross your subs over lower or not use them at all.

But on topic: no one uses Q, they use the manufacturer's recommended box sizes.

If I box simulator you say "wtf?"

 

[I800C0LLECT]

I got sick of the same old questions being asked...so I figured I'd try to spark some interests and maybe curiosity

 

[matt5112]

Ah.

Well start making these:

Leaks are awesome... Amirite or amirite?

 

[I800C0LLECT]

Leaks and cabin gain ftw. Kind of a high F3 isn't it? Must be kicker or something I've actually seen F3's on some subs as high as 40hz. wtf?

Oh wait...it's in title. Sound Splinter? I kind of figured it was a SPL sub.

 

[matt5112]

Its actually a SQ sub.

But its supposed to be a big box, not that tiny excuse for an enclosure that i modeled it in.

This is what I did with mine until i blew it up:

So onto things that matter:

Look how nice and close and even it is compared to maximum SPL based on excursion.... Oh this will be fun.

Qtc of .710. But I dont care about Qtc, I only care about excursion.

So lets apply a 50 Hz second order high pass...

Looks nice....

How about we add a second order LW filter with the following specs:

F0 Q0 Fp Qp Gain (dB)
50 Hz 0.4 10 Hz 0.4 28.0 dB

Just the cabin gain in that pic above.

So with the 50 Hz HPF combined with the speaker.......

Edit:

So heres what my sub looks like with the LPF of the third order and at 50 Hz in combination with cabin gain...

LW turned out a bit different with these numbers:

F0 Q0 Fp Qp Gain (dB)
58 Hz 0.85 25 Hz 0.7 14.6 dB

Too lazy to tune it.

Looks like this:

Now for the final result of the sub in the small box:

Well doesnt that look terrible....

 

[I800C0LLECT]

That really doesn't look too bad for the vehicle. Might need a little EQ but not bad. Just hope that the cross over points work well together. Phase can be a B in car audio. Most people don't realize that's where a lot of their quality is lost/poor installations.

 

[matt5112]

Don't ever ask me to do this for your install....

Because the proper way to do it is to measure the drivers in their position then start playing with filters...

I should lower the level on the mids, but too lazy.

Now i'm going to see what the SDX's look like without a HPF....

Exciting.... They COULD work without a sub but the overall SPL levels might not be there.

Still worth trying since I could once again have a trunk.

Perhaps install some small subs in the rear deck instead of having the stupid 18" taking up the entire trunk and giving me ass sag.

And I didn't once look at Q.