Sub with loud popping sounds

[J0NESI]

OK i have had this subwoofer for years and it still really good but there has always been this loud popping sound when the bass hits real hard real fast. Example - the opening scene to The Dark Knight when the guy brakes the window to repel to the other building or The Matrix when they blow the elevator in the lobby scene. I have done everything apart from turning the sub all the way down. I have had enough i cant take it anymore. Can anyone help with this.

[Blu-Dog]

Originally Posted by J0NESI

OK i have had this subwoofer for years and it still really good but there has always been this loud popping sound when the bass hits real hard real fast. Example - the opening scene to The Dark Knight when the guy brakes the window to repel to the other building or The Matrix when they blow the elevator in the lobby scene. I have done everything apart from turning the sub all the way down. I have had enough i cant take it anymore. Can anyone help with this.

Another poster just asked the same question today - here's the answer I sent him.

Yes. It's called "clipping". You can eliminate it by turning down the gain on the sub, or turning down the volume.

There are a few reasons it can happen. Usually, it's because there is not enough power to the driver. When there is a rapid change in the AC cycle at high output, the speaker driver is being pushed back and forth at max extension, for a prolonged period. This takes a lot of power, and the amplifier just runs out of juice.

However, it's still trying to get the message out, so while it's trying to pull the speaker in, it gets the news to push the speaker back out, and it winds up just slapping around aimlessly until it works up enough juice to do the job right.

Also playing a part is the port on ported subwoofers. While great attention is paid to setting port length and circumference by builders, ports are "tuned" to certain frequencies (usually at the optimum frequency of the speaker driver) and sounds that aren't in that sweet spot cause turbulence within the port - creating more pressure on the speaker, pushing back on it when it's trying to extend. This doesn't help any low power situations.

Most folks get mad and say, "I have to get a bigger amp, this is ticking me off", but this may overpower a smaller driver. That's when you get that nasty burning smell.

One other problem: The output signal from the data source. Sometimes source material is just sloppy - one soundtrack may have a bad subwoofer track, another may not. They are also running at different volumes, no two are the same. So the setting on your sub or receiver may be fine for one movie; and may freak out and clip like crazy on another. This is usually not a problem with brute-force gorilla subs, but smaller subs have headaches with this.

Anyway, if you turn it down, it goes away. Multiple subs at lower volume can sound great, without clipping, because when combined they up the sound pressure level without all that clipping nonsense.

Hope this helps...

[J0NESI]

thanks, i saw that one you posted earlier but didnt really know if it was the same thing.

[trevorc]

Sorry for a newbie question. In the earlier post the statement:

Yes. It's called "clipping". You can eliminate it by turning down the gain on the sub, or turning down the volume.

Are you refering to the volume knob on a powered sub or the sub level setting in the a/v receiver ?
thanks for assistance.

[Blu-Dog]

Originally Posted by trevorc

Sorry for a newbie question. In the earlier post the statement:

Yes. It's called "clipping". You can eliminate it by turning down the gain on the sub, or turning down the volume.

Are you refering to the volume knob on a powered sub or the sub level setting in the a/v receiver ?
thanks for assistance.

It's the sub control you turn down - and some subs have two settings, one for volume, and one for "gain".

Always set the "gain" about mid-setting. You can turn it up for louder sound, but it's not a good idea.

I'd keep the volume setting about halfway, too. Turning either one of them up can just make for lousy sound.

[browninggold]

Will the clipping hurt the sub? The only time I get this is during the Dark Knight toward the end of the movie (blu-ray) when Batman is in the vacant skyscraper with the hostages and joker. When his cable gun goes off I get a quick pop. Watched Kung Fu panda, iron man etc...no problems only at that one scene. I setup using a Denon 3808ci and Audyssey. My sub is a SVPB13 Ultra.

[primaz]

Probably for your room size and personal tastes adding another sub would solve this and make you happier. SVS are good subs but you might want to consider the Outlaw Audio LFM 1EX for $649 that can go a little lower than your SVS that the spec says it can go to 18hz; the Outlaw can go down to 16hz. I have that as my second sub and it is great on music and when I push the home theater for a movie it can handle any track at incredible volumes with ease Using a sound meter you can adjust the two subs to provide smooth even output to fill the entire room.

[browninggold]

I just checked my settings in my Denon 3808ci and I had in source select volume boosted up, I set at 0 and it did not clip at that scene and sounds alright.

[browninggold]

Originally Posted by primaz

Probably for your room size and personal tastes adding another sub would solve this and make you happier. SVS are good subs but you might want to consider the Outlaw Audio LFM 1EX for $649 that can go a little lower than your SVS that the spec says it can go to 18hz; the Outlaw can go down to 16hz. I have that as my second sub and it is great on music and when I push the home theater for a movie it can handle any track at incredible volumes with ease Using a sound meter you can adjust the two subs to provide smooth even output to fill the entire room.

Its not that it cannot go down low enough. The PB13 Ultra can go down to 10Hz, just depends on how many ports you have plugged...none or all three. I just had the volume in my Denon up too high.

[Luc M]

Those are all valid solutions. But you may also want to check the LFE level on your receiver. I'm not talking about the sub level on your receiver, those are two different things. Especially in your case since it only seems to happen on occassion.

[browninggold]

Thanks Luc M, that is exactly what it was. The LFE was boosted in Denon. Asked in the Audyssey thread. It was getting a double boost. Thanks