# Sub delay issue



## DJSLINKARD (Oct 8, 2012)

What's up guys? I just got got my new system up and running today and I've got a bit of an issue. I've heard of this problem before but never had to troubleshoot it myself so I'm hoping someone else has.

The problem: My sub has a delay to where it hits later than the rest of the speakers. It does this even at low volumes and will eventually just drop a hit or two out until it catches back up. Im not even talkin speeds like double bass from metal music. This is just dubstep or drum and bass that im playing and there is still lag.


The variables: Stock head unit to a PAC SNI-35 high level to low level converter
Then, from that adapter straight to a Rockford Fosgate P1000-1BD amp. 
From the output of the amp to a Rockford Fosgate T1D212.
The sub is wired down to 1 ohm and then wired to the amp.
The box is ported at around 1.8 cu ft.
My power and ground is all 1/0 knuconceptz as well as the big 3.



What am I missing here? Can anyone tell me why I am experiencing this delay? Don't get me wrong, this straight up bangs, but the delay is annoying and I have to fix it.


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## gjmallory (Apr 13, 2010)

The most obvious cause... IMHO, it's group delay. Are you sure you have that sub in the appropriate size/type box? 

Sent from my phone...


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## gjmallory (Apr 13, 2010)

If you have Time Alignment, you may be able to solve the symptoms (not the problem). The fix is probably a different enclosure size/type. 

Sent from my phone...


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## chad (Jun 30, 2005)

It's likely and integration issue between the midbass and subs.


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## Rs roms (Jul 12, 2012)

Group delay it is. Model your sub in bassbox or in any other and build a enclosure according to TS parameters.


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## chad (Jun 30, 2005)

gjmallory said:


> The most obvious cause... IMHO, it's group delay. Are you sure you have that sub in the appropriate size/type box?
> 
> Sent from my phone...





Rs roms said:


> Group delay it is. Model your sub in bassbox or in any other and build a enclosure according to TS parameters.


Srsly folks? Think about how many milliseconds your "group delay" really consists of and at what frequency.


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## DJSLINKARD (Oct 8, 2012)

Thanks for your responses guys. Someone from another forum suggested I try lowering the LPF to see if it changes anything so I may try that today though I really don't want it much lower than it is now. I doubt its an amp issue though and there is definitely not a problem with output of bass. 

I would like to add that I added a second T1D212 and while the delay is still there, it seems to be slightly less than before.

Here are the boxes I am using. Please don't flame me for using prefabs. I do not have access to tools to build my own box so this is the best I could do right now. Personally, I think these boxes are well made and they look super clean. I thought these specs would be ok for this sub though. What do you think?

http://www.atrendusa.com/atrend/kar...age=flypage.tpl&product_id=262&category_id=19

I have two of these firing up.


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## minbari (Mar 3, 2011)

chad said:


> Srsly folks? Think about how many milliseconds your "group delay" really consists of and at what frequency.


I agree with this. ported boxes have some of the worst group delay in any alignment and it is still not very audible.


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## Hanatsu (Nov 9, 2010)

I don't buy the group delay thing either and depending on the alignment the GD might not be that high. I've heard that 50% of the time cycle of a frequency might be audible, at 50Hz = 1/50 = 0,02 = 20ms/2=10ms. Agree with chad, integration between mids and subs would be the most obvious cause. Tried shifting polarity on the subs?


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## Oliver (Jun 25, 2007)

DJSLINKARD said:


> The problem: My sub has a delay to where it hits later than the rest of the speakers. It does this even at low volumes and will eventually just drop a hit or two out until it catches back up.


Under-powered

Get a battery that's new or rewire sub to higher impedance ( 4 Ohms, 8 Ohms ).

Maybe a capacitor might help.

System is straining under the load.

Possibly upgrade Big Three ?


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## Oliver (Jun 25, 2007)

chad said:


> It's likely and integration issue between the midbass and subs.


Chad may have something here !

Set your sub x-over to 12dB's , at whatever frequency.

Try your midbass about 24 dB's for highpass at from about 1/2 an octave higher.


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## DJSLINKARD (Oct 8, 2012)

Big 3 is done but I will admit that this stock battery is downright puny.


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## Spyke (Apr 20, 2012)

+4 on it not being a group delay issue, +3 on it being polarity related

Whoever told you to lower the lpf wasn't by any chance on caraudio.com were they?:laugh:

But yeah, swap polarity of the subs and see if that helps.


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## Spyke (Apr 20, 2012)

Oliver said:


> Under-powered
> 
> Get a battery that's new or rewire sub to higher impedance ( 4 Ohms, 8 Ohms ).
> 
> ...


Oliver, he said that it does it at low volume. Not a power issue.


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## qwertydude (Dec 22, 2008)

That's a lot of subwoofer for a little car. I'm betting it's not a delay issue, it's most likely an integration issue. What kinds of mains speakers are being used? Sounds to me like you're still running stock speakers and stock head unit. That's bound to get you integration issues. Do they have enough midbass response or enough power to balance out the subs? I've heard a lot of people claim time delays or all sorts of things and when I tell them it's integration issues they balk thinking they've set their systems up perfectly. I tweak simple EQ and crossover settings and magically these "delays" are gone.

The problem with listening to noisy bass music like dubstep is you're not going to get a good idea of what clean bass should sound like. I think the crossover is set too low which is often a newbie mistake thinking lower is better. What this does is mask the transient response of the woofer. In dubstep especially, the bass is a synthesized bass note often with an initial kick which is at a higher midbass frequency followed by a fading bass reverb which goes into the lower bass. If your crossover is too low you end up filtering the initial kick and accentuating the low bass that follows it and it sounds like a delay.

Try crossing your subs a little higher and setting your head unit to a flat EQ setting, means 0 bass, 0 mid, 0 treble.


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## DJSLINKARD (Oct 8, 2012)

qwertydude said:


> That's a lot of subwoofer for a little car. I'm betting it's not a delay issue, it's most likely an integration issue. What kinds of mains speakers are being used? Sounds to me like you're still running stock speakers and stock head unit. That's bound to get you integration issues. Do they have enough midbass response or enough power to balance out the subs? I've heard a lot of people claim time delays or all sorts of things and when I tell them it's integration issues they balk thinking they've set their systems up perfectly. I tweak simple EQ and crossover settings and magically these "delays" are gone.
> 
> The problem with listening to noisy bass music like dubstep is you're not going to get a good idea of what clean bass should sound like. I think the crossover is set too low which is often a newbie mistake thinking lower is better. What this does is mask the transient response of the woofer. In dubstep especially, the bass is a synthesized bass note often with an initial kick which is at a higher midbass frequency followed by a fading bass reverb which goes into the lower bass. If your crossover is too low you end up filtering the initial kick and accentuating the low bass that follows it and it sounds like a delay.
> 
> Try crossing your subs a little higher and setting your head unit to a flat EQ setting, means 0 bass, 0 mid, 0 treble.


Thanks for the well thought out response. I do think you're on to something here. I need to throw in some aftermarket components with their own amp and I was thinking about adding some kind of signal processor. I've never used them before but I've heard good things. I hear a lot about the RF 3sixty. Any thoughts?


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## DJSLINKARD (Oct 8, 2012)

Spyke said:


> +4 on it not being a group delay issue, +3 on it being polarity related
> 
> Whoever told you to lower the lpf wasn't by any chance on caraudio.com were they?:laugh:
> 
> But yeah, swap polarity of the subs and see if that helps.


Forgot to respond to this. They actually were from caraudio.com haha. I posted this same question on 4 or 5 different forums just to try and get a little variety though the only forum I've really participated in is SMD. I like what I see here though.


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## Spyke (Apr 20, 2012)

DJSLINKARD said:


> Forgot to respond to this. They actually were from caraudio.com haha. I posted this same question on 4 or 5 different forums just to try and get a little variety though the only forum I've really participated in is SMD. I like what I see here though.


There are some good/knowledgeable people here. I have def learned a lot from this forum.


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## gjmallory (Apr 13, 2010)

Only reason I said Group delay right away is cuz I experienced it when I first got into this hobby (10 years ago) ...of course it could have been the fact that I tried to build a 6th order bandpass using jigsaw and a paper copy of a namogram (graph to figure out port size). 
LOL! 
Guess I'm getting educated...the main reason I roam the halls of DIYMA.  

Sent from my phone...


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## MarkZ (Dec 5, 2005)

Group delay can have an impact on integration. That might be why you noticed that it had an impact. Just in an indirect way.

DJSlinkard, you've gotten some good advice here on things to try. Most of them deal with sub-midbass integration in some way, either by altering the response w/ EQ, crossover, and level tweaks, or by changing polarity (reverse BOTH subs with respect to the rest of the system), etc. Another thing you could try -- at least just for troubleshooting purposes -- is repositioning the enclosures in the back. Make them face backward instead of upward, and see if anything changes.


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## MBorgardt (Sep 25, 2011)

I got a simple idea.... reverse the polarity on the subs first and see if you hear a difference... and please give up on the group delay right now there is nothing wrong I can see with the box design.


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