Am I Pushing My Sub Too Hard? (odd noise)

[JP99]

Hey all --

I just bought a TSC-T100 10" Subwoofer. So far, I've been very impressed, but there is one nagging issue.

At what I would call 'strong' volumes, sometimes my sub will start to rattle. Sounds almost like I taped a piece of paper to the woofer.

I don't think I'm really pushing any extremes with the volume and sub levels... I have an Onkyo 605, the sub level is +2 (out of 12) and the sub's volume level is at 1 o'clock. Crossover on the receiver is at 80hz.

This happens when the volume is at 60 or so... which isn't ear-splitting by any means... seems like a good sweet-spot for enjoying movies. None of the other speakers in my 7.1 setup have a problem at this level.

One example is in Iron Giant... when the Giant runs and leaps into the lake. There is very heavy bass in his steps. When they hit, I hear that rattling sound.

My question is:

Am I pushing the sub harder then I reasonable should be able to given its specs... or is there a a possible defect in the sub... or just as important, would a similarly priced sub (like a Dayton 120) do the same thing?

 

[sawzalot]

The first thing I would check are all of the fastners holding things in place especially the driver, maybe something is loose and that would be the simplest of repairs, good place to start.

 

[jvgillow]

I would guess that you are probably overdriving it. Frequencies that are lower than the port tuning point can overwhelm a small ported sub like the T100. One option is to install a high-pass filter that rolls off the low-end content (T100 would probably need a 30Hz or 25Hz high pass filter).

The best and cheapest thing to do first is to make sure that you are using the optimal position for the subwoofer. Plop the sub down in your regular seating chair and do the crawl test. Wherever you hear the strongest clean bass is where you should place the sub. If you are using auto-calibration on your receiver make sure you re-run the setup after moving the sub.

The T100 has better capabilities that any sub I've heard for $160, but it's still a small budget subwoofer. A big ported sub like the SVS PB10 will have a lot more capability.

 

[markw]

If it's a powered sub I would hope that it has some sort of overload protection to prevent overload.

I'd check for a loose connector but call TSC first to assure this won't void the warranty although, if the rumors are true, I don't know if that really matters anymore.

 

[highfigh]

If it's a powered sub I would hope that it has some sort of overload protection to prevent overload.

I'd check for a loose connector but call TSC first to assure this won't void the warranty although, if the rumors are true, I don't know if that really matters anymore.

Overload is one thing, unloading is probably what is happening. Once the frequencies go far enough below the port tuning, there's little/no control over the cone's motion.

 

[markw]

Overload is one thing, unloading is probably what is happening. Once the frequencies go far enough below the port tuning, there's little/no control over the cone's motion.

Again, one would think a good engineer would know that and have incorporated a sub-sonic filter into the amp, no?

 

[shadyJ]

It sounds to me like port-chuffing. The only thing you can do to stop that is to turn the sub down, or you could also EQ out real low frequencies. If your receiver has a EQ, try to filter out everything below 25 hertz and then play back those scenes which are causing this sound to see if its still there.

 

[Adam]

The first thing I would check are all of the fastners holding things in place especially the driver, maybe something is loose and that would be the simplest of repairs, good place to start.

I agree. Also, contact TSC. I had a B&W sub that rattled at reasonable volumes, and it was due to a defect (not in the design, but they had a bad production run).

 

[JP99]

Thanks for all the responses!

I tried going into the receiver's manual EQ (it was on 'audessy' and I hadn't run it since getting the T-100).

I turned the 25hz option all the way down (to -6) and it did cut down on the rattling noise a bit... but didn't completely eliminate it either.

Just seems weird that my sub levels and overall volume are all fairly average, yet the sub is still struggling. I'd understand if I had the sub volume knob cranked or the sub level in the receiver up high.. but like I said, they're both pretty low.

And if the rattling happened more often, I'd just turn the sub's volume down a bit and forget about it... but I feel like I'm sacrificing too much bass just to avoid the rattling sound that might happen 2-3 times per movie.

I emailed TSC today and I'll let you know when/if I get a response.

Thanks again... and please keep any ideas/thoughts coming!!!

 

[highfigh]

Again, one would think a good engineer would know that and have incorporated a sub-sonic filter into the amp, no?

Define 'good engineer'.

 

[markw]

One who knows what to take into account when designing something.

Define 'good engineer'.

In this particular case, I'd say one who knew enough to put in a limiter circuit to prevent the driver from being pushed beyond it's physical limits and a subsonic filter to prevent frequencies lower than the driver could handle from making it to the driver.

 

[JP99]

Hey All --

Man, I feel like an idiot. So I got restless again today with the sub and decided to try and tinker with it, using the scene from The Iron Giant.

That rattling sound that I could have sworn was from the woofer, is indeed coming from the port!

In my defense, the sub is down-firing (as is the port)... so originally when I sat close by, I couldn't put my ear right up to the woofer. (I was a little scared about running the sub on somewhat high volume with it on its side).

But I did it anyway today, and the sound is definitely coming from the port. Just too much air going thru it at one time.

Is there any way for me to fix this myself? Otherwise, the sub sounds great.

Thanks again, and sorry for the confusion!!

Merry Christmas!

 

[ikeyes]

I wanted to add something I just discovered myself related to your issue.

My sub (PSW505) will chuff during some super low & loud sounds because I have to turn the gain up higher than is actually necessary due to placement.

When I stand about five feet behind my couch the bass almost doubles, but for now aside from rearanging my entire living room to compensate for this there is little I can do about it. I'm already plotting how I'm going to move everything around... just need a free weekend to get it done.

The only hard part is that this room is pretty much perfectly laid out for everything else except the sub... so I'm going to mess around with placement first but I don't think due to the shape of my room it will make much difference.

I'm going to do the test where you put the sub in the seating position and move around the room to try and work out something easier than moving all this furniture around.

Also I've read about filling the port with drinking straws can help cut down on the turbulence that causes cuffing... that'll be a cheap experiment so I'll give it a try as well.

 

[JP99]

Thanks for the input, Ikeyes.

I was thinking the same thing, and I'm sure that I can get better performance after I do the crawl-test. Problem is, I'm moving in 2 weeks and I haven't ordered a really long coaxial cable yet (the one I have is only 6ft). I'll definitely do that in the new place though.

The thing that worries me though, is that my levels are all pretty low. 1-2 O'clock on the sub volume, receiver sub level at +2 (out of 12)... I don't have an sbl meter so I can't figure out exactly how 'loud' I have the general volume, but it seems to me like standard movie volume (I know how subjective that can be).

So yeah... I should be able to get better sub performance out of lower settings once I find the sweet spot, but I would have thought that the port chuffing would only happen if you're really cranking the sub's volume levels.

 

[ikeyes]

Just spent several hours testing, and I've found a much better spot.

I tried the corner thing, more bass but less detail and next to no bass in the chest. In the new location I've got the levels at the same and even a bit higher in some cases with fuller bass sound and have reduced the chuffing to next to nothing.

Since I needed more distance to get closer to that sweet spot I ended up moving the sub to the right of the old spot which gave me about another 3' of distance on the lateral. This greatly improved things.

Sounds like if you are about to move forget about it for now, just think about where you might put it in the new location. Just wanted to say that it really did make a big difference after working out the placement, so I hope you get it square in your new digs.

 

[MatthewB.]

You said you hadn't run Audyysey since you bought the sub. This would be the first thing you should do. You could be overextending the sub with the current settings. Rerun Audyysey and hopefully it will lower the output volume. It set my SVS at -15 (and I only have the gain set at 2) and said my sub is 18 feet away (when it is only two feet away) it does this to compensate for boundary delays and room acoustics. I tried moving the distance closer and didn't sound nearly as good as when Audyysey said it was 18 feet away.

 

[JP99]

Haven't run Audyysey yet... but I plan to call TSC on Monday to figure out the problem.

I don't think Audyyssy is going to correct the fact that I hear major port noise at reasonable volumes, with all the settings set very reasonably. I just don't think I should have to be this delicate with a subwoofer. If I turn the settings down to accommodate the most intense scenes, then I'm left with too little bass response in the majority of the movies.

FYI... I did email their support at 12/22/08, and got nothing in return.

Ikeyes... where did you decide to place your sub?

 

[anamorphic96]

Calling TSC is probably useless since they are going out business and running on a skeleton crew. But you may get lucky.

How big is your room ?

I owned the ASW 10 and its port would make chuffing sounds when pushed to hard. The T300 would do this as well when pushed to its limits.

It definitely sounds like the sub is being over driven and your sub settings seem a bit on the hot side. Have you measured the subs output and balanced it to 75db with all the other channels ?

 

[JP99]

The sub's volume knob being at 1 o'clock and the receiver set to +2 out of 12 seems like I'm pushing it too hard?

Not being sarcastic... just nobody answered that particular part of my question before, so I assumed those settings were fine.

I don't have an SPL meter to do the Db levels yet.

My room is fairly large... 20x15x15. Moving soon, and the HT should be in a smaller room, so hopefully that'll help.

I'm just really surprised that a sub could perform so well, but the port can't handle it. This is fairly normal for the price-range then?

 

[anamorphic96]

The sub's volume knob being at 1 o'clock and the receiver set to +2 out of 12 seems like I'm pushing it too hard?

Not being sarcastic... just nobody answered that particular part of my question before, so I assumed those settings were fine.

I don't have an SPL meter to do the Db levels yet.

My room is fairly large... 20x15x15. Moving soon, and the HT should be in a smaller room, so hopefully that'll help.

I'm just really surprised that a sub could perform so well, but the port can't handle it. This is fairly normal for the price-range then?

That room is way to big for a sub like that. It is definitely being over driven. To fill up a room like that you would need four T-100's. Even then it might not be enough. Something like dual HSU VTF-3's or SVS PB12's is what you would need for good deep bass with strong output.

Not trying to knock the T-100. It's a solid budget sub but designed for small to medium rooms only.

My room is 12x17x8 and the ASW 10 I used would struggle at higher volume and chuff. I upgraded to a HSU STF-2 and things are much better. I'm also using a Velodyne SMS - 1 to eq the sub as well.