Excursion Question

[Muzykant]

Hello All,

I have a question regarding the sealed subs that I own. I own a pair of SVS SB-13 Ultras and a single SB-2000. I noticed recently that they behave quite differently when presented with the same material. With SB-2000 the lower you go in frequency below 20 Hz, the more the cone moves. With the Ultras the opposite seems to be true.

For example, when playing "Bass I Love You" track, SB-2000 has a considerable amount of movement reproducing the 17 Hz tone, and moves even more while hinting at the 7 Hz (shorter) tone. The 17 Hz tone has a lot of energy and in comparison seems louder than the main bass line. With the Ultras it is exactly the opposite: the main bass line is very loud and heavy, while the 17 Hz tone is almost not present at all, and neither is the 7 Hz one. I see just a little cone movement at 17 Hz and almost zero at 7 Hz.

Both subs are of sealed design from the same manufacture. Why is there such a difference? Is there a rumble filter employed in the Ultras that is not present in SB-2000?

P.S. These subs are located in different places and cannot be directly compared in the same room.

 

[WaynePflughaupt]

SVS has long been known to employ limiters and EQ to their subs. It’s really impossible to compare one to another in this regard.

That said, the answer to your question can found by comparing SVS’s own graphs. As you can see the SB13-Ultra drops about 23 dB between 30 Hz and 10 Hz, while the “lesser” SB-2000 drops only 15 dB. So yes the SB-2000 should perform better with infrasonic material.

SB13-Ultra

SB-2000​

Regards,
Wayne A. Pflughaupt

 

[Muzykant]

Thank you, Wayne. I suspected this to be the case.

In my experience, the SB-13 is more of a bass driver than a true subwoofer. It does sound great with majority of music, though.

Having said that, overall I like the SB-2000 better. I wish they came up with it before I bought my Ultra. I could buy 4 of them for the price of two Ultras and still have change.

 

[Sheep]

SVS has long been known to employ limiters and EQ to their subs. It’s really impossible to compare one to another in this regard.

That said, the answer to your question can found by comparing SVS’s own graphs. As you can see the SB13-Ultra drops about 23 dB between 30 Hz and 10 Hz, while the “lesser” SB-2000 drops only 15 dB. So yes the SB-2000 should perform better with infrasonic material.

SB13-Ultra

SB-2000​

Regards,
Wayne A. Pflughaupt

Those are not equal graphs....

I know, the subwoofers are different, but the nominal dB level is different. The Ultra is playing a 90dB level, and the SB2000 is playing 100dB.

If you're running 2 ultras, and 1 SB2000, I think placement and room interactions would need to be equalized. You'll need to use the same room, same spot, and same listening location to determine the exact difference between units.

SheepStar

 

[annunaki]

Correct me if I am wrong but aren't the Ultras vented and the SB obviously a closed box design. That being the case what you are witnessing is the difference in enclosure design. As a woofer nears the tuning frequency it requires less excursion due to the gain in efficiency in using the vent to make the majority of the air movement. Once the audio goes below the tuning frequency in a vented design then excursion will dramatically increase due to the enclosure "unloading". With a closed box design a woofer is the sole way to move the air. Thus it will continue to move as far as possible or as far as the power available will drive it. In the Ultra design you likely will not experience this as the amplifier has high pass filters built in to prevent that from happening. In an "unloaded" scenario, the power handling on the woofer will decrease by half and one risks potential damage to the driver itself.

 

[Muzykant]

Thanks for your reply, Annunaki. My Ultras are sealed (SB-13). I think there is some sort of internal filter in the Ultras that cannot be disabled. It is definitely not their room gain compensation feature, which is set to off on both my Ultras.

I just want to say that I do not dislike my Ultras. They are amazing for music, and I am very happy with them. It's just that the bass does not extend as deep as I thought it would given their size, power and price. Not a problem for music at all, though.

 

[Irvrobinson]

In my experience, the SB-13 is more of a bass driver than a true subwoofer. It does sound great with majority of music, though.

I'm not following you. You think the SB13-Ultra, which Audioholics measured as being capable of putting out 98db at 20Hz, 2 meters from the box outdoors, isn't a true subwoofer? Based on those measurements I think the SB13-Ultra qualifies as a *very* capable subwoofer.

As an aside, I also think we're in the midst of a subwoofer horsepower war, just as the automobile industry is in a horsepower war. The difference is that while you can usefully feel the difference between a car with a weight to power ratio of 10lbs per HP and one with only 7lbs per HP, I think it would be very difficult to hear the difference between a sub that can do 98db at 20Hz in Audioholics tests and one that do 106db at 20Hz, unless you had a very large room indeed, and listened at very high levels.

 

[monkish54]

THX reference for movies is 115db peaks with regards to the LFE. 98db @ 2 meters is child's play.

That's only 104 at 1 meter.

I haven't seen the review, but if the SB13 starts to be taxed at 98db @ 2 meters it's a woofer not a subwoofer.

My W15GTI MKII can handle 115db 20hz up and 111db 17hz and up. With the extreme dynamic range in LFE, high SPLs are absolutely necessary to reproduce films and video games accurately. From 98db to 106db should be just around twice as loud.

In fact, even 20hz is not low enough. If you look at the LFE content in films many films go down to the 15s, even 10s. While this can't be heard it CAN be felt and is the reason some people own 8, 10, etc subwoofers.

FWIW, for music peaks are only 105db at THX reference.

 

[Irvrobinson]

THX reference for movies is 115db peaks with regards to the LFE. 98db @ 2 meters is child's play.

That's only 104 at 1 meter.

I haven't seen the review, but if the SB13 starts to be taxed at 98db @ 2 meters it's a woofer not a subwoofer.

My W15GTI MKII can handle 115db 20hz up and 111db 17hz and up. With the extreme dynamic range in LFE, high SPLs are absolutely necessary to reproduce films and video games accurately. From 98db to 106db should be just around twice as loud.

In fact, even 20hz is not low enough. If you look at the LFE content in films many films go down to the 15s, even 10s. While this can't be heard it CAN be felt and is the reason some people own 8, 10, etc subwoofers.

FWIW, for music peaks are only 105db at THX reference.

I'm not buying it, Monkish. When I was testing my sub, 100db at 20Hz at my listening seat was making me nauseous. Not to mention that numerous things in the room that I didn't know could rattle rattled. I get that some movies have 15Hz content, and I'm also on board with the notion that tactile perception is not logarithmic like hearing and goes far lower than hearing, but the levels you're talking about are nutty for most of us. Of course 20Hz at 98db is child's play when you're willing to have 600L of subwoofer in your room, but I figure you're in the top 0.01% with that set-up. You're like a person with about $300M in assets compared to the rest of us, to make an analogy. So maybe the SB13-Ultra is only like having $1M in assets, and perhaps to someone with $300M that's child's play, but just as most would call someone with $1M rich, I think the SB13-Ultra qualifies as a subwoofer in the industry.

 

[Muzykant]

Yes, my sealed Ultras do play 20 Hz and even a couple of Hz below that, but below that the sound pressure drops dramatically compared to my SB-2000. At 12 Hz I do not feel the pressure in the room, but just hear a faint harmonic.

I am sure it can hit 98db at 20 Hz at full power. It's just that at that volume setting 40 Hz would be unbearable, and 80 Hz would make me deaf. My SB-2000 does not get that loud (though, enough for me), but my ears detect less difference in pressure as the frequency drops.

 

[Irvrobinson]

Yes, my sealed Ultras do play 20 Hz and even a couple of Hz below that, but below that the sound pressure drops dramatically compared to my SB-2000. At 12 Hz I do not feel the pressure in the room, but just hear a faint harmonic.

I am sure it can hit 98db at 20 Hz at full power. It's just that at that volume setting 40 Hz would be unbearable, and 80 Hz would make me deaf. My SB-2000 does not get that loud (though, enough for me), but my ears detect less difference in pressure as the frequency drops.

12Hz is a tough test. Have you optimized room placement for the 20Hz range?

 

[Muzykant]

12Hz is a tough test. Have you optimized room placement for the 20Hz range?

I have not found a good position anywhere along the front wall. I can't use the side walls because of bookcases, while rear placement would block doors. The only location that boosts subsonic frequencies is inside a closet, but placing the subs there would take away from 90% of other bass. I use these subs for music as well as movies.

 

[Sheep]

I have not found a good position anywhere along the front wall. I can't use the side walls because of bookcases, while rear placement would block doors. The only location that boosts subsonic frequencies is inside a closet, but placing the subs there would take away from 90% of other bass. I use these subs for music as well as movies.

I would split them up. I've never found co-locating to be a good idea when I'm trying to even things out.

SheepStar

 

[mike c]

it's not just SVS that applies EQ to their sealed subs. unless you want a sealed sub rolling off at 40-50hz, you NEED EQ boosts at the low end. so i would say, any and all sane subwoofer manufacturers would EQ boost their sealed subwoofers.

with regards to the rolloff difference, it's not that there is MORE of a limiter on the SB13, but there would be MORE of an EQ boost with the SB2000. i would think that if tested, the SB13 would still have more output at all the subsonic frequencies as compared to the SB2000. (larger woofer, larger enclosure and more power and all)

-0-

OP, you should ask SVS/Ed Mullen about the excursion thingy though.

but without reading carefully the thread, aside from the visual excursion difference, what sound difference do you hear?

the SB13 is a lot "cleaner" (less distortion) than the SB2000, could it be what you are hearing "Extra" with the SB2000 is actually distortion instead of actual content?

 

[Steve81]

Yes, my sealed Ultras do play 20 Hz and even a couple of Hz below that, but below that the sound pressure drops dramatically compared to my SB-2000. At 12 Hz I do not feel the pressure in the room, but just hear a faint harmonic.

I am sure it can hit 98db at 20 Hz at full power. It's just that at that volume setting 40 Hz would be unbearable, and 80 Hz would make me deaf. My SB-2000 does not get that loud (though, enough for me), but my ears detect less difference in pressure as the frequency drops.

Are you able to measure the frequency response you're getting at the seats from the SB13? Might also be worth going through the SB13's settings to make sure you don't have any filters engaged by accident, particularly the room compensation.

In any case, as Mike mentions, it's not that the SB2000 is more capable than the SB13, it simply has more EQ applied. The SB13 has a couple channels of PEQ you can play with to see if you can improve things (though you'll need measurements to make good use of this).