# Subwoofer out of sync with music



## italyix (Sep 9, 2007)

Hi all,

I am new here and ust installed an Arc Audio 12D4 in a sealed box 1cf. the box is a pre-fab. (I know...).

Anyways, the sub is powered by and Arc KAR 300.2 bridged to 700w and actively crossed by Arc crossover at 75Hz @24dB. Gain is halfway on the crossover and min on the amp.

When the music is on, the subwoofer is not in sync with the music, but hits later than the actual music track.

What is going on? Do I need tuning?

This is my first "high end" system in a car.

thank you for the help.

-Andrew


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## demon2091tb (May 30, 2005)

swap the phase, 0 to 180.

But Exactly how late is the sub.......?


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## azngotskills (Feb 24, 2006)

in otherwords, switch in the positive and negative on the amp or at the subwoofer


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## italyix (Sep 9, 2007)

Ho do I describe how late it is. Lets see, let 1 represent the low note that the music is letting out of the sub. I hear the 1.5, then the 2 note hits and i hear 2.5.

Make sense?

I'll try the phase.

-Andrew


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## ErinH (Feb 14, 2007)

hmmm. Wonder if adjusting the x-overs could fix this if phase doesn't work out?


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## Weightless (May 5, 2005)

Is there any delay in the signal via a processor of some sort?


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## italyix (Sep 9, 2007)

Signal comes from the HU to the x-over to the amp, then out to the sub.


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## quality_sound (Dec 25, 2005)

what HU?


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## italyix (Sep 9, 2007)

quality_sound said:


> what HU?


Alpine 9885


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## DonutHands (Jan 27, 2006)

my guess would be level matching.


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## npdang (Jul 29, 2005)

It's not "hitting late", it's just you have a big peak/dip in the frequency response that exaggerates certain frequencies.


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## italyix (Sep 9, 2007)

So,

how would you fix it? Work with the phase and x-over points?


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## npdang (Jul 29, 2005)

First thing I'd check:

1. Level matching ... see if the sub is simply turned up too loud.

2. Excessive low frequency ... see if cutting with an eq anywhere from 30 to 60hz helps.

3. Xover point between mid and sub ... try reversing sub polarity, and playing with a wide variety of highpass and lowpass cutoffs and slopes. Sometimes you may need to stagger them out a bit, such as highpassing the mids at 60hz, but lowpassing the sub at 120hz.


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## quality_sound (Dec 25, 2005)

Doesn't the 9885 have a delay on the subs? Maybe he turned that all the way up instead of the level???


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## mfenske (Feb 7, 2006)

I'm thinking that if he's got TA available that he should delay the front channels as the sub is likely the furthest speaker from him. If it's behind (in terms of time) the other drivers I see two options:
1. Move sub closer. Probably not do-able.
2. Delay other channels to more closely match subwoofer.


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## italyix (Sep 9, 2007)

The 9887 has time alignment, not the 9885.

thank you all for the suggestions. I will try them out when I get off work today.

-Andrew


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## chad (Jun 30, 2005)

Is it in a school bus?


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## jj_diamond (Oct 3, 2007)

my sub sounds less "boomy" when phased. when i set it to 180° it sounds tighter.


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## invecs (Jul 30, 2005)

I suggest lowering the lowpass to around 50Hz @24db or lower...and level match the sub with your frontstage. Put the highpass at around 80Hz and experiment with the slopes. In most cases, there is a peak from 40-80Hz so it is important to leave a gap between xover points and do some equalizations. 75Hz is too high specially if you take into account cabin gain.


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## MarkZ (Dec 5, 2005)

chad said:


> Is it in a school bus?


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## italyix (Sep 9, 2007)

Its a Evo IX.

I fixed the problem. Just reversed the polarities at the amp and the problem vanished. Now have it set at 120Hz @ 24dB and the mids at 75Hz. 0 degree phase. I'll tweek it some more over the weekend.

Thanks alot for everybody's input.

-Andrew


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## invecs (Jul 30, 2005)

Staggering frequencies can cause phase shifts. Good thing it is working in favor for you.


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## GlasSman (Nov 14, 2006)

Try getting that sub filtered no higher than 55 hz to 60 hz. And have the mids high passed where the sub stops. Experiment with the slopes.


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