Is it important to have a sub that can go below 20hz? (1 Viewer)

[Ryan T]

I have my Tempest tuned to 16.4 HZ and crossed over at 45HZ. I've also had the same driver in my 230L sealed box. I would say with movies it is VERY nice to have a sub that can go under 20HZ but defiantly not required. Most the bass people precieve as low is actually in the 30 to 40 HZ range. If i remeber correctly movie theaters cut off around 30 HZ. I think THX is also boosted insanely high at 30 HZ to make the bass seem the feal really deep. When i play the monsters inc demo with my tempest during the 10 HZ door pound it "sounds" very wierd. It really is inaudible but you can literaly see things shakeing. I can't see much use in haveing a sub that is tuned to around 10 or 12HZ though. From what i understand a subs tuneing point is were the greatest boost from the port is. The further away form the port tuneing the less it boosts the output(except when you go lower than the tuneing then it completly unloads). With most drivers today they start falling off around the high 20's to mid 30's or so. So the port wouldn't be helping much at all in the 20 HZ range. but once you get one of the very few DVD's that go below 20 HZ's it would help. So it's just mot worth while to tune a sub as low is 12HZ.



Ryan

 

[Chuck Schilling]

Why are y'all arguing about the theoretical range of human hearing? Get yerselves to an audiologist, and have your own hearing tested, then you'll know for sure where to tune your sub.

 

[Sebastian]

Yeah, looks like Tom and Ron are not as nice as we once thought, they are now official business men. The funny things is, if I ever had to buy a sub, SVS would be my first choice. However, I will always choose DIY, cheaper and better! Yes my friends, you can build a better sub than SVS.

Back on topic,

 

[MikeLi]

Chuck Schilling hit the nail on the head... go have your ears checked. Maybe you need to feel it more because you can't hear it. While I do like to feel the explosions a bit I find feeling every little bit of base anoying and that also means that your sub is not properly calibrated. Regarding the other post... I know what you mean.. my wife is completely happy with the speakers in the RPTV even though I have spent thousands on speakers and equipment. She does have to drag me to the theater but only about once a year will I go now. Sound much better at home and I hate being around all those people.... plus if I need to get up for something you can't beat that pause feature you dont get at the movies.

 

[Lewis Besze]

Yeah, if that would be that simple.There is phenomenon called harmonics,and many objects in the romm will vibrate at different frequencies.Calibration won't do jack for this only room treatment,or remove some of the "offending" objects.

 

[Justin Ward]

Before I had my SBB4 Tempest I thought the Sauron explosion at the beginning of LOTR was low bass. Actually, just before that explosion when the ring drops there seems to be a ton of subsonic information. It just feels like the room becomes pressurized. Can anyone else confirm this?

 

[John F. Palacio]

This would require an answer from the folks at SVS. I can only guess that they have opted for higher output for the majority of cases rather than lower frequency response for the rare material that has it. But this is just a guess.

Keep in mind that the SS series as well as the 16-46's are still tuned to 16Hz.

Happy Subwoofing!

 

[GeorgeJM]

Is that really true? Since I've never heard of the term "underported", what does that mean? What I'm saying is that it seems to me that plugging a port simply raises the air velocity in the remaining port(s) so you're more likely to get port noise, but otherwise there's no difference.

 

[Reginald Trent]

This is a interesting topic. As the owner of a 16-46 pci I choose it because it covers the most frequencies of all SVS subs. Albeit not quite as loudly as its liitle brothers (25-31 & 20-39) but then they don't go quite as low.

 

[Lewis Besze]

Which also limits the woofer's output,that's underported. See Dustin's post #31 on the top.

 

[Edward J M]

I'll throw in my $0.02:

1) The Ring Drop is centered at 25 Hz, per waterfall charts.

2) The SS is tuned to 18 Hz (this is a custom tune for SVS, between a 20-39 and a 16-46).

3) I can hear/feel a difference on my PB2+ between the 25 Hz tune and the 20 Hz tune on only a handful of DVDs (and I've got all the popular big bass hitters). The ability to go subsonic to about 15 Hz is nice for the few rare DVDs that actually contain information that low.

SVS offers the 25 Hz tuned models because the VAST majority of DVDs don't contain significant information below about 22 Hz. Not surprisingly, the 25 Hz tuned SVS models are actually flat (or even exhibit a mild rising response) to 22 Hz in room before the SS filter kicks in.

A 25 hz tuned SVS does justice to about 99% of all DVDs on the market. If you want to capture that last 1%, then tune it down to 20 Hz (if it has variable tuning) or buy a 20 Hz tuned model.

4) When discussing the PB2+, the term "underported" needs to be taken in context. Yes it is underported compared to the 25 Hz tune. Yes, if you model it at xMax and Vd, you will note the woofers can move more air than the two ports should be able to handle without audible port compression. And yes, if you push it hard enough with a 16 Hz organ note you can ultimately introduce audible port chugging, at which point your vision is blurring and everything in your house is shaking.

Two flared (both ends) 4" vents can move a LOT of air before audible port compression becomes an issue. The PB2+ in the 20 Hz tune is only underported if you are bench racing at the extreme ragged edge of the performance envelope or just being plain stupid and pushing something like the Sound Hound organ CD WAY beyond reasonable listening levels.

Bottom line - SVS has to draw the line somewhere on the design board, and the PB2+ in the 20 Hz tune can play loud enough in the 15-20 Hz region to satisfy almost anyone's tastes before audible port compression occurs.

5) Here is the actual in-room FR of the PB2+ in all three states of tune. While I tested it in the 16 Hz tune, I see no reason to run it that way, as the additional loss of port area is not offset by the increase in deep extension; there just aren't enough DVDs out there with information in the 10-15 Hz region to make it worthwhile. If you wanted to troll in the 10-15 Hz region all the time, you would have been better off buying two 16-46 PC+ than a single PB2+.

Regards,

Ed

 

[Dustin B]

I'll aggree with pretty much everything Edward has said. The only caveat I'll add is the PB2 and PB2+ are very different in their port airflow capablilities. The PB2+ with one port plugged still has more cross sectional area than a stock PB2.

 

[GeorgeJM]

Thanks guys, I knew about port flow velocity increasing with decreased port cross-sectional area, but had never heard that the increased velocity caused decreased volume contribution from the port.

 

[Charlie B. Ch.]

Deleted.