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Discussion Starter #1
I bought a pair of these....i put each of them in its own .56 cuft box....wired together in parallel to make a 4ohm load to my amp. This is a car audio install so that is what we do.

The amp is 600watts x1 at 4ohm.

I am getting what i can only describe as excessive flutter out of them...unless i turn the gains down so far that i just get a soft thump.

I have tried stuffed and unstuffed....LOC and direct speaker level inputs...

the SQ is very good....but there is just not enough output before they start fluttering and i can hear that flutter over the music.

I have them lowpassed at 60hz and have raised that to as high as 100....doesn't really change anything.

Is there anything i can do or am i just not going to be able to get more than a soft tap out of them?

When they are fluttering....they are not bottoming...or clipping....but it does not seem to good for the driver.

I am not some kid playing 10hz rap music....this is playing acoustic music with a kick drum.Dave matthews Band "Cornbread" off of a prerecorded Live at Piedmont CD to be exact. I use this because i have the same DVD that i can play in my HT for reference.

Thanks for any comments... It feels like the box is way to big?? But that is what was told to me to use by CSS.
 

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Discussion Starter #3
It very well could be a leaky box ....i am on my way to get weather stripping now.

There is no hi-pass on the amp....but i have a ton of spare power...maybe a passive 6 or 12 db on the speaker line?

Thanks!!! I will report back on the closed cell foam. I spent awhile yesterday sealing up the box best i could, but just assumed the basket would seal itself..it has a slight foam strip on the underside but VERY slight....
 

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The box joints are a priority as well. If you're not absolutely sure of their integrity, use a latek caulking compound on all interior seams. If you use silicone to seal the seams then let it cure first before you mount the sub. Silicone fumes have been known to eat the glue that holds the surround to the frame.
maybe a passive 6 or 12 db on the speaker line?
As long as it's effective around 20 hz or so.
 

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Discussion Starter #5
I did use silicon on every joint...and i did let it cure over night.

Is there a way to tell if the box is 100% sealed? Back when i was building boxes it was always assumed that if you push on the cone it must return noticeably slow.

Of course this was before the internet...now i cannot find a definitive answer. I have read that returning slow means i HAVE a leak...*rolling eyes*

anyway i will know more in a couple hours.

thanks!!
 

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Discussion Starter #6
OK..i think we are on to something here...

weather stripping made it worse....which may be a good thing.

Here in vermont we have nothing to choose from ever. They had no closed cell foam in souther vermont...so i picked up the best i could find. It was . But i tried it in hopes. No such luck,

So i puled the box...pulled the wires and woofers and amp off and i am going to spend some time doing it right....

might take a few days....but i am determined to strip all the silicone out of the inside and use something like liquid nails to seal every joint and cover the 5 holes i drilled in the box to run wires thru....and i will report back.

thanks!!
 

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Discussion Starter #8 (Edited)
I tried the amp on another subwoofer....and it was fine. But i have not tried this sub on a different amp.

I am having a HUGE amount of trouble sealing this box....

Is there a definitive way to determine if it is sealed? I have always gone on the assumption that if you push down on the driver and give it a few seconds to equalize, then it should then take a few seconds to noticeably return slowly.

This is not happening...

I have bondo'd almost then entire outside of the box now..and i have tried 2 types of foam weather stripping.

I am off to the store now to find rope caulk. After that i am going to fire it up and if it fails i will throw the entire mess into the fire:hissyfit::hissyfit:
 

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you should be able to hear air escaping when you push the sub in
what is the voltage output on the head unit?
What radio do you have?
 

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Discussion Starter #10
Update and answers:

I do not think this is the woofer any more...i tried something this morning and it seemed to eliminate the woofer.
Pushing down with all 230lbs of my girth on the box itself in my car and the noise was not present. Thinking it was coincidence, i turned the gain up and weight on no noise...weight off noise...

of course i do not know how to fix this...i did not screw the box together...but i did glue it and used abotu 10 clamps per joint so i know the box is solid...so it must be resonating with something in the trunk.

Answer, i do not know what the output voltage of a Mini Cooper HU is, but i have used both a LOC and speaker level inputs and i have a pretty strong signal.
 

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Discussion Starter #11
more updates...its not the box...i took the woofer out and held it in my hands when it was playing and the cone is slapping against the spider...is this something that i can return?

I will call meniscus tomorrow.,,in the meantime i am thinking i wil throw together a box for a NHT 1259 i have laying around......maybe ,75 cu:nerd:
 

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is your box siting on top of the spare tire cover?

it could be something under the cover and when you put your weight on it, it goes away.

more updates...its not the box...i took the woofer out and held it in my hands when it was playing and the cone is slapping against the spider...is this something that i can return?
you can not turn the volume up with the sub out of the box, it will bottom out if you do so
 

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Discussion Starter #13
is your box siting on top of the spare tire cover?

it could be something under the cover and when you put your weight on it, it goes away.
Thats what i was thinking at first...there are some metal brackets that are against the box.

But the noise was the exact same noise when i took the driver out of the box...at the exact same passages.



you can not turn the volume up with the sub out of the box, it will bottom out if you do so
It really is not bottoming out...IMO its a poor design that needs to be addressed...i am being told its reaching its mechanical limits. I am not sure i understand that wording...but to me it sounds lik the sides of the woofer cone are bumping into the spider...

Like if you put your finger on the cone while its playing....only much softer....
 

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Discussion Starter #15
Modeling shows the subs limits with your setup, a Hi-Pass filter at 20 hz would eliminate any problem you are experiencing.

but doesn't putting the sub in a .5 cu ft sealed box in effect roll it off above 20hz? Maybe a smaller box?

I do not have a SSF on the sub amp...if i had any confidence in this driver i would ad a SSF somehow...
 

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i did ..i moved on.....now trying to decide what to buy next:nerd:
I have a 10" in my truck, box 2cft tune to 28hz and it sounds really good and I just did a 12" on a Mercedes and that thing rocks really hard, ported box :T

good luck!!
 

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Discussion Starter #20
I have a 10" in my truck, box 2cft tune to 28hz and it sounds really good and I just did a 12" on a Mercedes and that thing rocks really hard, ported box :T

good luck!!

I need to be around 1 cuft in my mini cooper...thats about half the "boot"....most of the decent 10's seem to have a mounting depth of 6+ inches..that is also a concern for me.

which is why i am looking for the perfect pair of 8's....maybe they don't exist.
 
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