Differences on ported and sealed subs

KEW

KEW

Audioholic Overlord
I wouldn't bring discussion of distortion into this too much. Compared to groundplane measurements, the way distortion behaves in room is very complex. At many frequencies it can be a lot less as a percentage, but at others it can be much more.
So are you saying that measuring CEA2010 in-room is bogus? I do notice that the distortion levels at max passing SPL (for the CEA standard) are, on average (but not always),quite a bit lower in-room. I would interpret this as not as much power is needed for each 5dB increase (with room gain). I would guess there is a little bit (but not at all severe) of a null at 20Hz where the distortion increased.

We also have to keep in mind that It takes a lot more SPL in deep frequencies for the extension to be worthwhile. Sure a single 10" sealed sub can get a flat response down to 10 Hz in-room, but it doesn't make a difference if its deep bass output runs out of gas before it hits anything that can be humanly sensed. It is for this and other reasons that I generally don't advise people to buy sealed subs with expectations of room gain to deliver deep bass, unless they know for a fact that their room does do this, and the sub has enough displacement to make a real difference in that range.
I assume you mean 15" sealed sub.
So is 101.5 dB at 10Hz not perceptible?
I know we are out of audible range.
Honestly, I'm not sure I really want 10Hz in my room, but since Ricci measured it, it is a great demonstration of a fairly modest sub showing amazing capability after room gain is included in the measurement.
Since teh sub is actually showing greater SPL in-room at 10Hz than 12.5 or 16Hz, it is reasonable to believe it may test out at 7 or 8 Hz as well, but I don't know that it matters. I have seen measurements on sealed subs getting below 10Hz. I suspect Steve81's will get there easy enough!
 
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shadyJ

Speaker of the House
Staff member
So are you saying that measuring CEA2010 in-room is bogus? I do notice that the distortion levels at max passing SPL (for the CEA standard) are, on average (but not always),quite a bit lower in-room. I would interpret this as not as much power is needed for each 5dB increase (with room gain). I would guess there is a little bit (but not at all severe) of a null at 20Hz where the distortion increased.


I assume you mean 15" sealed sub.
So is 101.5 dB at 10Hz not perceptible?
I know we are out of audible range.
Honestly, I'm not sure I really want 10Hz in my room, but since Ricci measured it, it is a great demonstration of a fairly modest sub showing amazing capability after room gain is included in the measurement.
Since teh sub is actually showing greater SPL in-room at 10Hz than 12.5 or 16Hz, it is reasonable to believe it may test out at 7 or 8 Hz as well, but I don't know that it matters. I have seen measurements on sealed subs getting below 10Hz. I suspect Steve81's will get there easy enough!
CEA-2010 can't properly be done in-room. The reason why Josh does it is to illustrate what the outdoor measurements can translate into for indoor performance as an example. He doesn't do it much, just enough to make a point. And, of course, the measurements that he gets is only valid for his room, and for that specific subwoofer and microphone placement within the room.

I don't know how much SPL it takes to sense a 10 Hz tone, but I would not be surprised if it took more than 101.5 dB. Here is a chart of the thresholds that were found for the sensation of infrasonic frequencies:

I have to question how some of this research was done since it is so old, so I wouldn't take any of this to the bank.
 
ryanosaur

ryanosaur

Audioholic Overlord
I have to question how some of this research was done since it is so old, so I wouldn't take any of this to the bank
But even averaged by eye... it shows an upward trend in the data for the reported sensitivity to the infrasonic tone. Would be cool to see a new test with modern technology and technique laid on top of this!
Thanks for sharing that, Shady!
 
lovinthehd

lovinthehd

Audioholic Jedi
Back to the moving of big heavy objects with a dolly whether it be a sub or an appliance or furniture....movers blankets/pads are a good thing. :)
 
H

Hokies83

Audioholic
Actually, more laughing at you wanting an ultra 16! :p They are beasts... but really not necessary for your space.
You have a battle with acoustics to win, and one of those isn't going to overcome that.

If you want to do something crazy, get 4 Hsu ULS15mk2s. A little squad of these in your room will destroy you! And you can get 4 for only $500+shipping ($812) more than that 1 PB16Ultra.
Hell, 4 SB2000 will only cost $2600, and be better balanced for your room. (Just being pragmatic.) :p
Where can you get 4 Hsu uls15mk2 for $500 plus ship?
 
H

Hokies83

Audioholic
Read the complete sentence: context is a b!tch! :eek::oops::cool:
Still don’t get it lol, just see $500 plus ship maybe I’m just slow... but asking cause if they are sign me up for 4 lol

Are you saying 4 of them would only be $500 more then the pb16?
 
lovinthehd

lovinthehd

Audioholic Jedi
Read the complete sentence: context is a b!tch! :eek::oops::cool:
Well, it is somewhat awkward....had to reread that one myself originally (altho understood it). One PB16 vs four ULS15 with shipping (since it's not included in the price like SVS does)....just work out the math and it makes sense I'd hope....I didn't double check :)
 
ryanosaur

ryanosaur

Audioholic Overlord
Still don’t get it lol, just see $500 plus ship maybe I’m just slow... but asking cause if they are sign me up for 4 lol
true that...
4 ULS15s will cost $500+shipping more than 1 PB16 Ultra.
 
ryanosaur

ryanosaur

Audioholic Overlord
Well, it is somewhat awkward....had to reread that one myself originally (altho understood it). One PB16 vs four ULS15 with shipping (since it's not included in the price like SVS does)....just work out the math and it makes sense I'd hope....I didn't double check :)
*fingers crossed
This cold sucks, but I hope I haven't lost all my sensibilities... ;) Though its not outside the realm of possibility! (To be fair).
 
ryanosaur

ryanosaur

Audioholic Overlord
ULS15mk2 Dual Drive: 1499 + S/H: $156 =$1655 x2 = $3310
PB16 Ultra: $2499.99
difference = $810.01
I estimated 812.
C+? ;)
 
William Lemmerhirt

William Lemmerhirt

Audioholic Overlord
If you are familiar with CEA2010 charts, there here are DataBass measurements that show the effect of moving this sub into Josh Ricci's room and measuring from the LP (which is a penalty on SPL, right. These charts are for the PSA XS15se, which I consider a good, but far from special subwoofer. It retailed for $800 and I think I got my pair for $1350 or $675 each.
Without room-gain, the low end is 88.9dB at 12.5 Hz.
With room-gain, the low end is 101.5dB at 10Hz!
You can also see that distortion has decreased, so you can't very well argue that this driver is being worked extra hard to produce these low frequencies

So how much power and excursion is required? 550W is nothing special for a sealed subwoofer and this is no stout JL Audio driver! This modest sealed sub accomplishes this feat at well below $1000! The point I am making is it does not require some super hardware or the driver to work any harder to do it, it is just free gain!



PS, In the past, I remember seeing some information involving the size of Ricci's listening room where these measurements were taken. I cannot find it now, but I do remember it was a decent sized room, not a small bedroom.
I am rather surprised not to see any dramatic nulls or nodes, but I guess Ricci knows the spot to place a single sub for good response at the LP!
Hey Kurt! Appreciate your observations. I’m on a trip with my family so I’ll have to save my deeper thoughts until I get time.
I just wanted to share these, as maybe somebody would want a refresher. I enjoy them, and was surprised.

https://www.data-bass.com/data?page=content&id=80
https://www.data-bass.com/data?page=content&id=2
 
S

Steelers252006

Audioholic
I’ve read the review from master switch on the SVS PB-16 Ultra many times over the last month or so, and so still get those “audio chills” each time. If I did pick up just one of them, would a “logical” spot be in the corner just to the right of my right tower speaker facing straight ahead?

I’m still reading like crazy on the HSUs, too, would simply go dual there with both being on the inside of each tower. The SVS PB3000s seem like a strong option as well.
 
KEW

KEW

Audioholic Overlord
I don't know how much SPL it takes to sense a 10 Hz tone, but I would not be surprised if it took more than 101.5 dB. Here is a chart of the thresholds that were found for the sensation of infrasonic frequencies:

I have to question how some of this research was done since it is so old, so I wouldn't take any of this to the bank.
I definitely wish there was more consistency among those studies to give them more confidence!
Since I have 4 of these subs (actually two XS15se and two S-15's - which are PSA's update of the XS15se with ICE instead of bash amplifiers). My theoretical in-room SPL at 10Hz would be 110.5 (if I assume similar room gain to what Josh Ricci experienced).

110dB at 10Hz would be inaudible by a 1934 study, at the threshold of audibility by a 1936 study, and audible by 1958 and 1967 studies. I'm inclined to believe methods improved over 20-30 years, but wouldn't bet my firstborn on it!

The reason why Josh does it is to illustrate what the outdoor measurements can translate into for indoor performance as an example. He doesn't do it much, just enough to make a point. And, of course, the measurements that he gets is only valid for his room, and for that specific subwoofer and microphone placement within the room.
Yes, and that is exactly the point I want use to challenge ignoring the effect of room gain!
You definitely know a lot more about subs than I do and it would be rather foolish of me to attempt to argue with you about them!
However, I have noticed that Josh seems to think room gain is relevant - enough so to include in his databass write up that the roll-off of the XS15se should complement typical room gain. Obviously one of DataBass's major functions is to assist people in evaluating subs and when Josh makes a statement like that, I see it as reminding us that room gain is a reality in the final determination of how a sub will perform under the conditions we actually listen to them!
So, if we have two people knowledgeable about subs offering contradicting points about the relevance of room-gain, I will inquire about the contradiction!

From my perspective, the reason for making Anechoic (or outdoor faux-anechoic) measurements is to provide a repeatable standard of measurement. Obviously in-room measurements would vary tremendously and not provide comparable measurements.

However, it also seems rather strange how endeared we are with flat anechoic response into deep bass!
I certainly looked at it that way when I first started looking at subwoofers (after years of reading speaker FR curves); however, for me, a couple of bad experiences with in-room bloated bass from subs that measured flat anechoically, cause these statements from Josh and SVS to resonate with me!
I am convinced that with some of my first efforts to get a good subwoofer, room-gain resulted in such an increase in low bass that Audyssey could not control it (I think Audyssey tops out at something like 8 to 12dB that it will reduce a signal by - maybe someone knows the exact figure?). I also believe Steve81 encountered this issue along his audio journey.
 
S

shadyJ

Speaker of the House
Staff member
However, I have noticed that Josh seems to think room gain is relevant - enough so to include in his databass write up that the roll-off of the XS15se should complement typical room gain...
The key word in your argument is 'typical.' But what is the typical room? 15'x20'? 15'x30'? 10'x20'? These rooms will all produce differing levels of gain. Its not just about dimensions, its about openings too. The gain that you get from the low-end roll-off of your subs that suits your room could easily get lost in another room that isn't that much bigger, or maybe one that is smaller but has an opening to another area. You are arguing for a one-size fits all curve that will only work to produce a flat response in some rooms. Subwoofers, like other loudspeakers, should generally aim for a neutral response, and that is a flat curve, and the user should be able to EQ the curve to their tastes. Many subs have a default flat response but allow the user to tame the low end. SVS, MartinLogan, Paradigm, Hsu, and others. That is the best solution. I wouldn't want manufacturers to assume a particular amount of room gain and voice their subs accordingly. Give me a flat response and a way to change the response to suit the room or my tastes.
 
KEW

KEW

Audioholic Overlord
Hey Kurt! Appreciate your observations. I’m on a trip with my family so I’ll have to save my deeper thoughts until I get time.
I just wanted to share these, as maybe somebody would want a refresher. I enjoy them, and was surprised.

https://www.data-bass.com/data?page=content&id=80
https://www.data-bass.com/data?page=content&id=2
Thanks for the links, the second one was for cars, but a fun read - some pretty phenomenal increases from a auto cabin!!!

The first link compares a specific room (4200 cu. ft.) vs outdoor ground-plane response. In the conclusion, the author (I could not find a name?) makes the following statement:
At 32Hz and 12Hz there was a net SPL loss in output at the listening position compared to anechoic one meter or two meters groundplane. Sure, there was a lot of gain seen in other areas of the frequency range but if clean headroom and flat response is to be maintained at the highest playback volumes, it is the areas with the least gain that are of concern.
I understand what he is saying, but it is in contradiction to what Gene says in his "How to Calibrate Multiple Subs" video where he says the concern is the peaks and not to worry too much about the dips!
Using Gene's approach, the focus would be on trying to reduce the 11dB spikes around 25Hz and 45Hz which is more consistent with the offensive elements I have found when starting with a sub that is relative flat throughout the audible range.
 
KEW

KEW

Audioholic Overlord
The key word in your argument is 'typical.' But what is the typical room? 15'x20'? 15'x30'? 10'x20'? These rooms will all produce differing levels of gain. Its not just about dimensions, its about openings too. The gain that you get from the low-end roll-off of your subs that suits your room could easily get lost in another room that isn't that much bigger, or maybe one that is smaller but has an opening to another area. You are arguing for a one-size fits all curve that will only work to produce a flat response in some rooms. Subwoofers, like other loudspeakers, should generally aim for a neutral response, and that is a flat curve, and the user should be able to EQ the curve to their tastes. Many subs have a default flat response but allow the user to tame the low end. SVS, MartinLogan, Paradigm, Hsu, and others. That is the best solution. I wouldn't want manufacturers to assume a particular amount of room gain and voice their subs accordingly. Give me a flat response and a way to change the response to suit the room or my tastes.
I agree with what you are saying that all room will be different in their specifics.
However, I still need to refer you to the fact that it is Josh Ricci and SVS that use the term "typical".
I don't believe they think there is a "one size fits all" solution; however, I do believe they are saying those responses are to some degree beneficial.
 
William Lemmerhirt

William Lemmerhirt

Audioholic Overlord
Thanks for the links, the second one was for cars, but a fun read - some pretty phenomenal increases from a auto cabin!!!

The first link compares a specific room (4200 cu. ft.) vs outdoor ground-plane response. In the conclusion, the author (I could not find a name?) makes the following statement:

I understand what he is saying, but it is in contradiction to what Gene says in his "How to Calibrate Multiple Subs" video where he says the concern is the peaks and not to worry too much about the dips!
Using Gene's approach, the focus would be on trying to reduce the 11dB spikes around 25Hz and 45Hz which is more consistent with the offensive elements I have found when starting with a sub that is relative flat throughout the audible range.
I believe that was josh Ricci.
 
Steve81

Steve81

Audioholics Five-0
however, @Steve81 is the only knowledgeable subwoofer guy I know (there may be others, but I don't know about there systems) who has gone the single sub route with a Funk 21.0LX!
I've got dual subs (still have the 18.0 in play) but given the relatively small seating area I care about, the single 18.0 did a pretty good job for my purposes. May not be the case any more, but IIRC, Bill Fitzmaurice (https://billfitzmaurice.info/) ran with a single Table Tuba for his rig.
 
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