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#326996 - 10/30/10 12:29 PM Unable to detect defective driver with test tones
bdpf Offline
aficionado

Registered: 06/28/08
Posts: 769
Loc: Toronto, Canada
A couples of weeks ago I posted on another thread a problem that I was having with one of my woofers.
http://www.axiomaudio.com/boards/ubbthreads.php?ubb=showflat&Number=325402&page=3
Here is a summary:
Originally Posted By: bdpf
This weekend, I was by myself for I couple of hours so I decided to watch the first Ironman at loud volume. Something is bothering me. During the scene where Ironman is about to go to Afghanistan to rescue the villagers and he enters sonic speed, one of the woofers on the M80s made a strange noise (I don't have a sub). It sounded like if there was a hole on the driver, or maybe similar to what I would imagine being port noise on a sub even though I never heard what a port noise sounds like. I repeated this scene a couple of times getting the same effect. If I lower the volume, I don't hear it no more. The only other time that I experienced that was when I watched Percy Jackson and the Olympians during the first scene where Poseidon gets out of the water and steps on the ground (again, at loud volume). Worried that one of my woofers would be damaged, I played some music with heavy bass loud but everything sounds fine. Do you think one of my woofers could be damaged? Could this be that my receiver only has 100 wpc and at this particular moment it requires more? Could it also be that these scenes have very low frequencies and the M80s are trying to play them but can't? Both times, it seemed to come from my bottom right woofer. Any ideas?

The scene on Iron Man happens at 1h16.
After trouble shooting I found that this was coming from one of my woofers. I contacted Axiom and they sent me a new one.
I followed the advice of Chris and downloaded some test tones and frequency sweeps but wasn't able to reproduce this particular issue. I played tones from 5Hz to 200Hz at 0db on my receiver and everything sounds fine however when I play these 2 specific scenes mentioned above I am able to reproduce it every time. What's up with that?
Today, I replaced the woofer and everything is fine now. I still can't understand why I couldn't reproduce that with the test tones. Any ideas?

As I mentioned on the other thread, I would love to leave my M80 set as full range but would it be safer to set them as small with a crossover set at 40Hz so they're not trying to play frequencies that they can't play properly?

Another thing, I think I might be paranoiac now but during this same scene, at the same moment he enters sonic mode, I hear a grizzling noise (sounds like when you connect a speaker to the amp with the amp on) coming from either the tweeters or the mids. I am pretty sure it's part of the soundtrack as it's happen on all 3 mains but it's jut that I never noticed that before. Can someone that has the movie confirm that? Like I said, since I had this, I am paranoiac and question everything I hear crazy crazy crazy
_________________________
Bruno
M80s/VP180/QS8s/EP600/AVR-890
------------------------------------
"The problem is choice..."

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#326998 - 10/30/10 12:44 PM Re: Unable to detect defective driver with test tones [Re: bdpf]
BlueJays1 Offline
connoisseur

Registered: 09/19/08
Posts: 4116
Loc: Porch,enjoying Bombay Sapphire
Do those sounds happen at lower volumes during that scene? Try to figure out if the sounds are coming from the tweeter or the mids. If it is a problem with the soundtrack it should be audible with most volume levels and not just at extreme levels. The problems with the noises coming from the bottom two drivers are solved now, correct? I wonder if the mids on the M80 are run full-range like they are with m60? That can be an intense scene at loud volumes. It sounds like you might be clipping your receiver as well. This is a tough one.
_________________________
Iím armed and Iím drinking. You donít want to listen to advice from me, amigo.

-Max Payne

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#327001 - 10/30/10 01:11 PM Re: Unable to detect defective driver with test tones [Re: BlueJays1]
chesseroo Offline
axiomite

Registered: 05/13/02
Posts: 5171
Loc: western canada
bdp, several years back i had a buzzing issue with my new M60s. I heard it on a few tracks and narrowed the buzzing noise to a few seconds during a guitar strum of "Let my love open the door" (Pete Townshend) from the Grosse Pointe Blank soundtrack.
I also heard it on a Holly Cole song during a strum of a bass.

I contacted Alan first if i recall and he had Axiom send me a new driver. I then heard it, less so, on another driver and they sent me a second replacement.
The buzzing went away except for that one Pete Townshend song and only more mild in one of the replacement drivers.

After a lengthy discussion with Alan and after having sent him a copy of the disc to replay on his own system (copied only for research purposes of course), we concluded that it was likely just something in the recording or an exact frequency-vibration cause which quite clearly was rather limited.

That little issue drove me crazy for awhile but these things do pop up from time to time.
Keep working on isolating the sound and don't forget that it could actually be something in the recording.

Then there was my issue with the EP350 port chuff...



Edited by chesseroo (10/30/10 01:11 PM)
_________________________
"Those who preach the myths of audio are ignorant of truth."

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#327006 - 10/30/10 01:17 PM Re: Unable to detect defective driver with test tones [Re: BlueJays1]
BlueJays1 Offline
connoisseur

Registered: 09/19/08
Posts: 4116
Loc: Porch,enjoying Bombay Sapphire
Can you also check if DRC (Dynamic Range Compression) becomes automatically enabled when you are playing this specific disk? In your receiver settings and maybe there is such an option in your Blu-ray player as well.
_________________________
Iím armed and Iím drinking. You donít want to listen to advice from me, amigo.

-Max Payne

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#327022 - 10/30/10 07:13 PM Re: Unable to detect defective driver with test tones [Re: BlueJays1]
bdpf Offline
aficionado

Registered: 06/28/08
Posts: 769
Loc: Toronto, Canada
Hi Dr, yes the problem with the woofer is now solved, this one was only happening at loud volumes during this particular scene (I was unable to reproduce it with the test tones).
This "grinding" happen at all volumes (even very low) and on all 3 mains at the very same moment of the bass explosion. It seems to come from the tweeters (all 6 of them). The more I listen to it, the more I think it might be part of the recording and they want the explosion to sound like this.
I have the DRC set to OFF on both devices.
_________________________
Bruno
M80s/VP180/QS8s/EP600/AVR-890
------------------------------------
"The problem is choice..."

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#327023 - 10/30/10 07:32 PM Re: Unable to detect defective driver with test tones [Re: bdpf]
BlueJays1 Offline
connoisseur

Registered: 09/19/08
Posts: 4116
Loc: Porch,enjoying Bombay Sapphire
While not M80's I tried this with a pair of M3's and a VP150 set to large with no subwoofer. I found nothing in the soundtrack that sounded off other than I was missing a lot of the mid to lower bass frequencies. They were simply not heard. I did however hear something sort of like you describe a little after he takes off. It comes from the Iron Man suit. I think you are correct assuming that it is part of the soundtrack.
_________________________
Iím armed and Iím drinking. You donít want to listen to advice from me, amigo.

-Max Payne

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