Wicks' E46 M3 Build. Hertz 3-Way Set from Tony D!

[Wicks]

Who's been keeping up with Tony D's (DAmore Engineering) Education videos???

I have and did some tests to look at some real world effects.

Hike up your pants, its gonna get a little nerdy in here for a post or two

There's a big misconception that a subwoofer/speaker has a constant impedance/load and stays that way regardless of anything.

Just because you're "wired at 1ohm", it doesn't mean your amplifier always "sees" 1ohm............far from it.

Here's an actual impedance sweep on one of my DC Audio XL12m2 D1 subs in free air from 10Hz to 200hz (both coils are wired in series for a 2ohm load):

You can see that at 10Hz, the sub starts out around that "nominal" value of about 2 ohms. The DC resistance would be a bit lower then that.

Notice what happens at 37Hz, the impedance shoots up to about 35 ohms!

For anybody that doesn't know, that point is the resonant frequency of the driver or "Fs".

It's normal and every audio driver does it.

Now another plot which I've been anxious to do for a while now.

A lot of people on this forum (and others) use the Torres calculator to design your ported boxes, I did.

The calculator can only tell you so much and it would be really nice to actually see how the box parameters came out after its built.

The IM-SG can help you do that unless you have access to an impedance meter which does the same thing.

Here is the actual impedance sweep of my two XL12's in my sub box.

This is the actual load that my DC5K amp will see at each frequency.

The doors and windows of the car are closed and the cabin is sealed up.

Now the plot has two peaks (Fl and Fh) and a dip in between them. The dip is the box's tuning frequency.

In Torres, my box calculated to a tuning frequency of 38Hz, 37Hz with the latest port extension I added.

Well you can see from the plot that my box is actually tuned to about 33Hz.

Very interesting!

Does that mean that the Torres calculator is way off?????

Nope, not at all. Every vehicle is different and that will also get incorporated into the impedance numbers as well.

Notice that the second peak of the ported impedance curve is at 47Hz and rises up to 15ohms.

The impedance peak of the raw driver measured about 35ohms with both coils wired in series to 2ohms.

In my box there are two of those ~35ohm-peak (2ohm-nominal) subs that wired in parallel so the resulting ~15ohm-peak makes sense.

Remember in Tony's video, he mentions that the impedance will change with the changing conditions of the car?

Well, here is another impedance plot of my sub box with the drivers door open:

Notice my tuning frequency went down to 32Hz and my second impedance peak dropped from 15ohms to 9ohms.

So my tuning frequency drops and my impedance goes down when the door is open.

A pretty graphical explanation of why my system gets louder with the door open.

Another curiosity,

My peak SPL meter score was ~148dB at 49Hz.

Meter in the kick panel, driver's door open.

Notice that's directly on the second impedance peak of about 9ohms.

So at my peak SPL measurement, my DC5K is only seeing a 9ohm load.

Anybody clamp their amps at their peak SPL frequency and get confused when they aren't getting "rated" power from the amp?

I was worried when I designed this box that I wouldn't be able to tune low enough, given my smaller box size.

Turns out my tuning isn't too bad after all.

Pretty interesting to see everything graphically.

[scooter99]

First of all I hate you for making me think this hard on a Friday! But second, thanks for pointing this out. I haven't kept up on all of Tony's videos and hope to catch up soon. But this almost makes sense to me. I'll re read it a bit later.

[Kyblack76]

Nice job Jaime. Sent you a message on fb

[nocturnalrites101]

nah he said he would get back to me, was just talking to the distributor not the owner. i didnt wanna be up his ass about it. soon as i know you will. If your looking to upgrade sooner then later let me know ill give you contact info and can speed things up

[elflako17]

HOLY FUCKKKKKK!!!!!!!!!!!!!!

how in the hell i missed this build log? where that hell was i? under rock lol? this build is just pure awesomeness. just wow all this custom work for this beautiful white m3 props bro props!!!!!!

just question any plans on wheels and tires? and suspension wise? plus any engine mod coming soon?

[Wicks]

nah he said he would get back to me, was just talking to the distributor not the owner. i didnt wanna be up his ass about it. soon as i know you will. If your looking to upgrade sooner then later let me know ill give you contact info and can speed things up

No that's fine, no rush, just curious.

No more big purchases until I wrap up this stage of the build.

I tend to get too many ideas brewing...

But I'm definitely curious so let me know!

[Kyblack76]

HOLY FUCKKKKKK!!!!!!!!!!!!!!

how in the hell i missed this build log? where that hell was i? under rock lol? this build is just pure awesomeness. just wow all this custom work for this beautiful white m3 props bro props!!!!!!

just question any plans on wheels and tires? and suspension wise? plus any engine mod coming soon?

Calm your tits.....

[Wicks]

HOLY FUCKKKKKK!!!!!!!!!!!!!!

how in the hell i missed this build log? where that hell was i? under rock lol? this build is just pure awesomeness. just wow all this custom work for this beautiful white m3 props bro props!!!!!!

just question any plans on wheels and tires? and suspension wise? plus any engine mod coming soon?

LOL. Thanks Man!

That comment makes it all worth it

I bought it with the replica CSL rims which I really like.

No big plans for wheels at the moment but who knows?

It also came with Koni shocks and H&R springs so it rides pretty damn good.

Very fun around the corners.

I had aspirations of tracking the car before I re-caught my car audio bug.

Not sure how it would do now with the extra weight in the trunk...

Engine mods?

When I finally get the audio side of this car done then I'd LOVE to add some forced induction.

It's a really fun car, but another 100hp would be perfect...

[elflako17]

Calm your tits.....

lol sorry ill try my best

the reason why i ask is that i am in love with the m3's.

there is a 2004 laguna seca blue m3 by my house an the guy does not drive it at all. this car is precious and i might talk to the guy to buy it. thsi color in particular was discontinued and you can only get it by special order in which sucks and its expensive as well

[Wicks]

HOLY FUCKKKKKK!!!!!!!!!!!!!!

how in the hell i missed this build log? where that hell was i? under rock lol? this build is just pure awesomeness. just wow all this custom work for this beautiful white m3 props bro props!!!!!!

just question any plans on wheels and tires? and suspension wise? plus any engine mod coming soon?

Calm your tits.....

Hey now!!!

With comments like that....the tits can do anything they want!