Rattling in AL IV Platinum

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Anatoray
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Rattling in AL IV Platinum

Post by Anatoray » Tue Feb 03, 2009 10:57 pm

Hi, I've owned a pair of Carver AL IV Plats for nearly a year now, and have been enjoying them for some time. At first, I did not have a proper set up to power them, and ran them with the woofers not recieving any signal, but now have them running on a pair of Adcom monoblocks. They sound beautiful, but the left speaker has a slight rattle whenever certain wavelegnths in the base occur. I have not been able to isolate which wave frequencies do it, but it is consistent on a select few. Volume does not appear to affect it in any way, as playing them loud or quiet produces pretty much the same rattle.

Does anyone have any idea where exactly this rattle is occuring and how I might go about fixing it?

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treitz3
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Re: Rattling in AL IV Platinum

Post by treitz3 » Tue Feb 03, 2009 11:10 pm

Yes sir I do and welcome to the forum.

Put your ear right up to the culprit. When you hear the frequency make the rattle, note the time on the disc. LP or whatever that it happened, turn up the volume and make it happen again. Scope out the speaker with your ear over all portions of the speaker where the grill is.

When this is done, get back to us. It's most likely a woofer for which there are replacements for and we can hook you up with them. In the meantime, pull up a chair, cop a squat and enjoy your new home at the Carver forum.

We'll talk to you soon enough.
In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence.

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Re: Rattling in AL IV Platinum

Post by Anatoray » Tue Feb 03, 2009 11:24 pm

Thanks for the fast response. I did what you suggested and have it pinned down to the bottom woofer. However, after pumping the volume way beyond sane levels the rattle became rather loud, and then suddenly got really quiet. Now it doesn't occur in that spot of the song anymore, unless I blast it, which I find very unusual.

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treitz3
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Re: Rattling in AL IV Platinum

Post by treitz3 » Tue Feb 03, 2009 11:31 pm

Ok, we have just located the issue. It's either a loose bond between the woofer and the housing or the woofer itself. Have you ever taken the grills off before? Front and/or back grills?
In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence.

The best way to enjoy digital music reproduction is to never listen to a good analogue reproduction.

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Re: Rattling in AL IV Platinum

Post by F1nut » Tue Feb 03, 2009 11:40 pm

A case of the rotting surrounds. Time to buy new woofers.
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Re: Rattling in AL IV Platinum

Post by Anatoray » Tue Feb 03, 2009 11:44 pm

I have not taken off either grills before.

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treitz3
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Re: Rattling in AL IV Platinum

Post by treitz3 » Wed Feb 04, 2009 12:03 am

You can take the grills off from the back. There are about 6 or 7 screws to remove it [forgive me if I'm incorrect on the # of screws as it's been a while]. Once the back grill is off, you now have access to the front grill screws. You guessed it, remove the screws to take the front grill off.

At this point you will have a visual as to what's going on. If you see rot at he foam, well replace the woofer. If you do not, get back to us and we'll lead you in the right direction.

Oh, word of warning. Be careful pulling the back grill off. Do not separate the wires or add any tension to them. Pull a Mc-Gyver to prop it up to insure that there is no damage to that. ;)

You'll see what I mean when you get to that point.
In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence.

The best way to enjoy digital music reproduction is to never listen to a good analogue reproduction.

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Re: Rattling in AL IV Platinum

Post by F1nut » Wed Feb 04, 2009 1:37 am

Excellent advice Tom. I have only one thing to add, when removing the front grill, have someone hold it in place as you remove the screws so that it doesn't slide down the face of the panel and scratch the hell out of it.
Political Correctness...defined

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In a recent press conference, President Obama remarked, "If I had a city, it would look just like Detroit."

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Re: Rattling in AL IV Platinum

Post by Reese » Wed Feb 04, 2009 2:53 am

Welcome, Anatoray!

One other possibility of cause (it happened to me!): When you get the back speaker cover off -- check to see if a small square cross-over board with some electronic gizmos mounted on it has possibly come unglued from its moorings and may be hanging down onto a lower woofer's metal frame instead of being up where it belongs and out of the way. This caused some rattling/intermittent buzzing in one of my Amazings after moving from California to New Mexico -- in transit or whenever after being placed in the new location, this noise started up suddenly. Initially everyone thought it might be rotting speaker foam - and it turned out to be just a dangling crossover board reacting to certain frequencies and volume and needing to be put back up in place on the back of the speaker panel. It'd be great if that's the extent of your problem, too!
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Re: Rattling in AL IV Platinum

Post by skip » Wed Feb 04, 2009 7:23 am

Also note that the grill screws are square drive (robertson) and not phillips even though they look kinda like a phillips when you look at them. They will come out using a phillips driver, but you'll damage the screws if you don't use the square drive bit. Another thing to check is the plywood braces on the back grill cover that the mounting screws turn into. I had one that the glue failed on that caused a buzz. Treitz is most likely right though, probably a worn out woofer. If you find one is bad, I'd recommend replacing all of them as the rest won't be far from failing.
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Re: Rattling in AL IV Platinum

Post by Anatoray » Wed Feb 04, 2009 5:21 pm

Thank you everyone. I won't get to remove the panels until this weekend, but I will get back to you and post photos if I need visual aid. I'll also have to check if my roommate has the proper drill bit.

Also, while I'm at it, how do you suggest cleaning the wooden frame? My cousin whom used to own a pair said to just wax them.

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Re: Rattling in AL IV Platinum

Post by OBI56 » Wed Feb 04, 2009 5:37 pm

If they are black then you can use any good paste car wax (Carnauba works best), if they are Oak use a good coat of Tung Oil and bufff.
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Re: Rattling in AL IV Platinum

Post by F1nut » Wed Feb 04, 2009 8:50 pm

I'm pretty sure the oak panels have a lacquer finish, therefore tung oil should not be used, just wax them if you want.
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In a recent press conference, President Obama remarked, "If I had a city, it would look just like Detroit."

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Re: Rattling in AL IV Platinum

Post by OBI56 » Wed Feb 04, 2009 9:49 pm

I thought they were oiled walnut Jesse. I had originally written to wax them but then I remembered the oiled thing and changed what I had written. But, upon checking out the service manuals, it appears that the Oak Plats were indeed an oiled finish. Also, found the definitive answer to the question of the origianl Piano Black finish in the Original's Owners manual as below; being a Polyurethane Acrylic Enamel similar to what is used on fine automobiles.
Amazing Plat finish.JPG
Amazing Plat finish.JPG (56.29 KiB) Viewed 1049 times
Amazing Black finish.JPG
Amazing Black finish.JPG (79.45 KiB) Viewed 1050 times
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Re: Rattling in AL IV Platinum

Post by F1nut » Wed Feb 04, 2009 11:40 pm

Ah excellent Marc, I happily stand corrected on the oak finish.
Political Correctness...defined

A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.



In a recent press conference, President Obama remarked, "If I had a city, it would look just like Detroit."

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