vtf HO bottoming out, I think...

[dafeist]

Last two movies Ive watched on Bluray (Toy Story 3 and How to Train your dinosaur) have both made by VTF 3.3 HO w/turbo bottom out. At least I think thats what its doing. It makes a "clank" sound when the sub digs down. Ive never had it do this before on any movie, and I actually dialed the master volume on the AVR down 3 dbs before starting the movie. To be honest, I normally do not use the turbo but just recently plugged it in. When still on MO mode, the clank was quite loud. When I switched it to ME mode, it was lessened but still obviously there. I havent tried it with the turbo off and back at MO mode. Anyone think there might be something broken in the sub? Do these movies have an especially heavy low end that would overdrive the HO, even at a bit of reduced volume? Any advice would be appreciated. Thanks.

[Pete_Hsu]

Hi dafeist,

On some movies the LFE channel is running quite "hot" relative to the other channels. Provided that the subwoofer sounds fine with your other soundtracks, then the driver should be fine.

Are you using any auto-eq on your receiver?

What settings do you have on the back of the sub amp for volume knob, bass extension switch, and crossover switch?

Thanks

Sincerely,

[dafeist]

Nope, pcm straight from the ps3 to the avr and out. volume is no more than 9 oclock. Ive had it dialed with the spl meter to about 3-4 dbs hotter than the rest of the speakers. I usually have it without turbo and MO mode. However, since I have no mbm-12, I got tired of looking at the turbo being unused and slapped it on there but left it on MO after reading some of your posts regarding a "happy medium." Thats when I heard the clank. I switched it to ME and still heard it, but not as bad. I will be changing it back to No Turbo and MO and see if its still there.

[Pete_Hsu]

Very strange that the noise was worse when switching from bass extension switch in the '2 port open' mode vs. bass extension switch in the '1 port open' mode, doesn't really make sense to me.

For widest dynamic range, you should keep both ports open and bass extension switch set to '2 port open' mode.

Sincerely,

[dafeist]

Ok, took the turbo off and am back running it like I used to, MO, or both ports open. Ive even backed off the volume a hair from where its been set for the past 2+ years. Ive now heard the "clank" on a song. It was in only one spot and it was at the peak of my allowed volume setting, but it has never been there before and like I said, Ive actually turned the subs volume down a hair from before. The only thing that is still different from before is the sub's location. Ive moved it about 1 foot and turned the speaker from facing the wall (was about 2 feet from it) to facing the room, and moved it into the corner about 6" from the wall on both sides ports facing a wall. Ive tightened the screws holding the woofer in place and still get the "clank" where I havent heard it before. Is it possible that since the woofer was facing away from me before that it had been going on all along and I had just never heard it? I dont think so, but...?

[Pete_Hsu]

Hi dafeist,

I'm sure you would have heard it even in the original position with woofer firing into the wall.

At what master volume level did you hear the clank with that music track, and how much did you have to back down on the master volume level for it to go away?

Any chance that you can put it back to the original placement position?

Thanks

Sincerely,

[dafeist]

It was at 9 oclock before, now down a hair below that. It was set using an spl to be a few dbs hotter than the rest of the speakers.

I put it in the old position, still hearing the "clank." Again, its only when driven pretty good. But the issue is that ive never heard it or experienced it before.

[Pete_Hsu]

Sorry, what I meant is, how high is the master volume level (ie. -10dB, -12dB?, etc) on the receiver when you hear the noise, and how much do you have to back down (ie. 2dB, 3dB, 4dB?, etc) on the master volume level on the receiver for the noise to be inaudible from the listening position?

Thanks

[dafeist]

It was at -5 (stereo), backed it off to -8 and it went away. That was with music. with the two movies I referenced, was at -10 (pcm 5 channels hd audio). Backed it down to -15 and still heard it.

[Pete_Hsu]

It just looks like the driver is reaching it's linear excursion limits with these tracks. The subwoofer is running 3-4dB hot relative to the mains, and on those tracks the low frequencies may be exaggerated relative to the higher frequencies. Not sure why it wouldn't have happened earlier, but the driver itself will not lose excursion capability over time.

[dafeist]

So, whats the best configuration I can run to alleviate this as much as possible. Turbo, ME, etc.

[cacihome]

So, whats the best configuration I can run to alleviate this as much as possible. Turbo, ME, etc.

Running it in MO, without turbo, no port plugs, in a corner(as close to your seat as you can), would offer the highest SPL on that sub.

It is an excellent sub, so enjoy it.

[Pete_Hsu]

Yeah, the current configuration really does give the widest dynamic range.

[cacihome]

If you have it this way, and still need more output adding an MBM is an easy fix.

When I had my 3.3 turbo, and I added the MBM-12 MK1, it was a night and day difference, after a little tweaking of course.

Actually a friend of mine still has this combination, and he is very very pleased with it.

[dafeist]

does the addition of the mbm reduce the strain on the HO, keeping it from bottoming out as easily (not that it bottoms out easily, you know what I mean). Would selling the HO and picking up the new 15 be better than adding the mbm to the HO?

[Pete_Hsu]

Adding an MBM-12 does help performance of the true subwoofer since it no longer has to reproduce deep bass and mid-bass at the same time. That said, it seems that you really need significantly more deep bass headroom, so I would recommend selling the HO and getting a VTF-15H. You will notice a huge difference at all frequencies.

Sincerely,

[OU812]

does the addition of the mbm reduce the strain on the HO, keeping it from bottoming out as easily (not that it bottoms out easily, you know what I mean). Would selling the HO and picking up the new 15 be better than adding the mbm to the HO?

dafeist,

Are you sure this "clank" noise is not something else? Like a wire that is hanging too low inside the cabinet and perhaps hitting the port vents rapidly during high air turbulence inside the sub's cabinet.

The reason I mention this because that is exactly what happened with one of my Paradigm Studio 80's speaker. I kept hearing this loud noise coming from inside the cabinet when the speaker was driven hard. I took the bass driver out, and it turned out be a speaker wire that was flapping rapidly when the speaker was driven hard. I just then taped it up, tucked the wire back in, put the bass driver back, and viola! No more noise...

I think it would be worth it to check inside the sub.

[cacihome]

does the addition of the mbm reduce the strain on the HO, keeping it from bottoming out as easily (not that it bottoms out easily, you know what I mean). Would selling the HO and picking up the new 15 be better than adding the mbm to the HO?

Oh...yes it does. You will feel a more powerful setup. No doubt. Maybe an MBM is cheaper than buying an entire new sub, you'll have to check that.:D

[cacihome]

dafeist,

Are you sure this "clank" noise is not something else? Like a wire that is hanging too low inside the cabinet and perhaps hitting the port vents rapidly during high air turbulence inside the sub's cabinet.

The reason I mention this because that is exactly what happened with one of my Paradigm Studio 80's speaker. I kept hearing this loud noise coming from inside the cabinet when the speaker was driven hard. I took the bass driver out, and it turned out be a speaker wire that was flapping rapidly when the speaker was driven hard. I just then taped it up, tucked the wire back in, put the bass driver back, and viola! No more noise...

I think it would be worth it to check inside the sub.

Yeah. good idea.

[OU812]

Yeah. good idea.

I've own the VTF3-HO since 2006 and it never, never has bottom out. Usually it is my ears that quit first, the headroom of that sub is phenomenal.

[dafeist]

So do I just unscrew the driver and carefully pull it out to check for loose wiring?

[OU812]

So do I just unscrew the driver and carefully pull it out to check for loose wiring?

If you see the wire that connects to the sub and it hangs too low in there, chances are that it is hitting the sub's ports or some other part of the enclosure during heavy excursion.

[dafeist]

tried to take the driver out. wouldnt budge. feels like the foam edging is glued on.

[lradden]

It's not glued in it's just really heavy due to the magnet. I took the driver out of my HO once to see what it looked like and had to use a screw driver to pry it up a little.