Ive come to think that im over excurting said woofer.

[The Camry]

Posted earlier about box issue. Thought my box was tuned too high. Turned out its jjust fine at 32 hz.

Now im trying to get that real good low end. this stuff right here.



Sa-12 on 1000rms.

Also i get that the song has some clipping above 0db in it. Thats easily remedied with keeping the volume down so its not clipping the amp.

Now...Should i just turn to full tilt and turn up my subsonic filter until i hear that click click of over excursion go away? Assuming thats how you get great low end and not destroy your woofer?

AS you can see that graph, that build up under 30hz is still significant and i get that im hitting mechanical limits because lack of dampening under tuning frequencies..

just curious as if this is how you remedy that?

Click to read more...

 

[garychoffmann 10+ year member]

If the song has clipping in it, The amplifier will play the clipped signal. If you have a bad audio recording I would try and remedy that first

 

[The Camry]

Thats not the only song in the collection. Most are super clean and under 0 db. Just curious as to how to remedy the problem of over excursion

 

[Boominburban 10+ year member]

better amp with more damping ...

 

[The Camry]

Cuz thats informative...

 

[hispls 5,000+ posts]

God that must sound awful. If your goal is to play 28hz sine waves you'll need to do a little better than SA series 12" to not run into mechanical limits on 1000W.

 

[The Camry]

thats not a sine wave. its music. What makes you think its a sine wave?

 

[The Camry]

Alright. Will someone inform me on mechanical limits and low frequencies? im all ears or give me a link to read. is it just not possible to be playing 28-30hz songs on a sa-12 with 1000rms with good volume?

i wanna learn but im totally lost as too what i need to be understanding here.

 

[Boominburban 10+ year member]

Cuz thats informative...

Do some research and it would be ....

You say you want to learn, but it seems you really want to post smart azz comments ....You learn from research and experience ...

 

[The Camry]

Do some research and it would be ....
You say you want to learn, but it seems you really want to post smart azz comments ....You learn from research and experience ...

do you mean dampening of the slope of the SSF?

 

[Boominburban 10+ year member]

Damping factor is a number, derived from a calculation, given to an amp that tells you how well it can control the subwoofer. A higher number damping factor, means better sub control. Anything over 1000 is considered great. The old Kenwood 1023's had a damping factor greater than 1000, and it made 15" subs play as tight as 10's in anything but a completely junk enclosure.

You could take literally take a Pyramid sub in a ported box, on a 1023, and it would play as tight as any name brand in a sealed box ....

That is the quick version ...

 

[Boominburban 10+ year member]

Here you go, read this, and it should make it more clear ...

DAMPING FACTOR

Loudspeakers have a mind of their own. You send them

a signal and they add their own twist to it. They

keep on vibrating after the signal has stopped, due to

inertia. That's called "ringing" or "time smearing."

In other words, the speaker produces sound waves that are not part of the original signal.

Suppose the incoming signal is a "tight" kick drum with a short attack and decay in its signal envelope.

When the kick-drum signal stops, th

e speaker continues to vibrate. The

cone bounces back and forth in its

suspension. So that nice, snappy kick drum turns into a boomy throb.

Fortunately, a power amplifier can exert control over

the loudspeaker and prevent ringing. Damping is the

ability of a power amplifier to contro

l loudspeaker motion. It's

measured in Damping

Factor, which is load

impedance divided by amplifier ou

tput impedance. Let's explain.

If the speaker impedance is 8 ohms, and the amplifier

output impedance is 0.01 ohms, the damping factor

is 800. That's a simplication. Sinc

e the speaker impedance and amplifie

r output impedance vary with fre-

quency, so does the damping factor. Also, the impedance of the speaker cable affects damping. Thick

cables (with low AWG) allo

w more damping than thin cables with (high AWG).

The lower the amplifier's output impedance, the higher the damping factor, and the tighter the sound is. A

damping factor of 1000 or greater is consider

ed high. High damping factor equals tight bass.

How It Works

How does an amplifier control speaker motion? When the loudspeaker cone vibrates, it acts like a micro-

phone, generating a signal from its voice coil. This

signal generated by the speaker is called back EMF

(back Electro Motive Force). It travels through the

speaker cable back into the amplifier output, then

returns to the speaker. Since back EMF is in oppos

ite polarity with the speaker's motion, back EMF

impedes or damps the speaker's ringing.

The smaller the amp's output impedance, the greater is

the effect of back EMF on the speaker's motion.

An amplifier with low output impedance does not impede the back EMF, so the back EMF drives the loud-

speaker with a relatively strong si

gnal that works against the speaker's motion. When the speaker cone

moves out, the back EMF pulls the speaker in, and vice versa.

In short, the loudspeaker damps itself through the am

plifier output circuitry.

The lower the impedance of

that output circuitry, the more the back EMF can control the speaker's ringing.

To prove it to yourself, take a woofer that is not

connected to anything. Put your ear next to the cone and

tap on it. You might hear a low-pitched "bongggg" if

the speaker itself is poorly damped. Now short the

speaker terminals and tap again. You should hear a tighter thump.

 

[Boominburban 10+ year member]

I am not stating that this is your whole problem, but it seems that most modern amplifier companies are happy selling amps with only around a 200 df, which is not good ....

So it could be contributing to your issue ...

The lower the fq you are trying to reproduce, the more damping factor you need to properly control the sub ...

 

[fatboytyler]

Could it be that your box is way off? Way too small or too big?

 

[The Camry]

im not sure. Specs on ssa store for sa-12 says

1.75 ft^3 ported tuned to 30 Hz -- F3 of 26 Hz * Tune higher and use a smaller box for more SPL oriented setup (Use 1 - 1.5 cubes) * Enclosure can be as big as 2.25 ft^3 with lower power levels 1.00 ft^3 sealed -- F3 of 44 Hz * For SQ and space limited applications

box is 2.0- 2.2 cuft. so im thinking it might be too big for the amount of power im sending to it. 1000rms