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Your Home Theater ULF Score - Page 12

post #331 of 1882
Thread Starter 

This was a good exercise trying to estimate from a ported sub to its sealed counterpart. If I use the same methodology, I can get pretty close with a variety of subs. Here's the methodology I'm using for estimating (this was all derived by looking at data-bass measured results). Also, I'm estimating more optimistically in general (benefit of the doubt).

 

Again, this isn't perfect, but should get us pretty close.

 

Going from ported to sealed:

  • Sealed is aprox. 10db down at the ported subs tune. If the measured result is not exactly at tune, I'll subtract 1-2 db to compensate for the difference: 18hz tune, I'll use 8db down instead of 10db, since there measurement on data-bass is 20hz.
  • Example: The FV15HP outputs 108.1 at 20hz. The F15HP is it's sealed counterpart (using the same driver and amp), so I adjust it's 20hz output by 8db (FV15HP's tune is 18hz) to 100.1 at 20hz.

 

Estimating sealed max output from 20hz

  • Looking at data-bass, most sealed subs are down 10-12db at 12.5hz compared to 20hz. Being optimistic, I use 10db down to get to the 12.5hz
  • Example: Since I estimated the F15HP at 100.1 at 20hz, based on the above, it's 12.5hz output is 90.1db.
  • In order to determine whether or not a sealed sub can dig cleanly to 10hz, I referenced data-bass again. Looking at 20hz, the lowest output where a sealed sub has clean CEA output at 10hz is when it had 99db or higher at 20hz (LMSR12-Sealed). Generally speaking, any sealed sub that produced 99db or higher, was able to get clean output at 10hz.
  • To estimate 10hz output, looking at data-bass, most sealed subs are down 4-6db from 12.5hz. Being optimistic, I use 4db down from 12.5hz to get to 10hz.
  • Example: Since the F15HP is estimated 100.1 at 20hz (>=99db), I will estimate it's 10hz output. Subtracting 4db from it's 12.5hz estimate puts it at 86.1db at 10hz
  • For 16hz, I just took the midpoint between the 20hz output and the 12.5hz output.
  • Example: The F15HP at 20hz is 100.1, and at 12.5hz is 90.1. The 16hz output is estimated at 95.1db. 

 

Based on the above, I've filled in the blanks from 10-20hz for all sealed subs we've estimated so far. I've also completed some ported sub estimates based on mfg data being up or down certain db compared to their big brother ported subs on data-bass.

 

Note, I've re-estimated all Rythmik subs. The 20hz output looks more realistic to me compared to other estimates and data-bass data.

 

 

Look at the results, am I close here?


Edited by dominguez1 - 9/22/13 at 3:29pm
post #332 of 1882
Here is my ULF score @ 20Hz

Subs
1 SVS PC 12 Plus = 1.8
1 Occam Audio with CSS SDX/10 driver = .1

Room size
13x14.8 = 1456

ULF score
1456/1.9 = 776

It seems to me that the Occam Audio sub adds more than the .1 but maybe not at 20Hz. I use it near field at about 3 feet from the back of the couch with the SVS PC12 plus in the front. I also have 4 DIY 16 inch rounds to help with smoothing.

I really want to get 4 sealed subs in my room. Thinking maybe 4 of the CSS SDX 12 in 18 inch cubes. But is is hard not to just to SI or Dayton 18 at that point even with the boxes being much larger.
post #333 of 1882
"Look at the results, am I close here?"

i read your bullet points and it all seems about right and reasonable.
post #334 of 1882
"Its not there...Josh Ricci, the guy who tests the subs has mentioned it several times in the past. The XV15 had a base plate at the time that was not removed for testing so the mic could be placed accordingly in relation to the driver. This is why the numbers measure slightly low. I guess I need to start a donation thread to retest the XV15 since everytime I mention this it causes a conflict."

that little bugger relates to boundary gain. downfiring radiates pretty much true omni, so is at a slight disadvantage to a sub with the driver facing the mic and the enclosure forming a small wall behind it. a sub with a large front panel, such as the chase, has the most loading from this effect. the scores are slightly incomparable for that reason. the effect is great the higher the frequency as well. i wouldn't both with a retest, the scores aren't meant to be that accurate, but more to give an idea of about where each sub will be, not which one will have 0.5 db more at a given frequency.
post #335 of 1882
Thread Starter 
Quote:
Originally Posted by christmclean View Post

Here is my ULF score @ 20Hz

Subs
1 SVS PC 12 Plus = 1.8
1 Occam Audio with CSS SDX/10 driver = .1

Room size
13x14.8 = 1456

ULF score
1456/1.9 = 776

It seems to me that the Occam Audio sub adds more than the .1 but maybe not at 20Hz. I use it near field at about 3 feet from the back of the couch with the SVS PC12 plus in the front. I also have 4 DIY 16 inch rounds to help with smoothing.

I really want to get 4 sealed subs in my room. Thinking maybe 4 of the CSS SDX 12 in 18 inch cubes. But is is hard not to just to SI or Dayton 18 at that point even with the boxes being much larger.
Small rooms are great, aren't they?

Curious, where did you get your information for yours subs? What output did you use? i will update my list!
post #336 of 1882
Thread Starter 
Quote:
Originally Posted by LTD02 View Post

"Look at the results, am I close here?"

i read your bullet points and it all seems about right and reasonable.
Thanks LDT02. I extrapolated everything from data-bass numbers. It's good to know that it looks reasonable from a different lens.
post #337 of 1882
no problem.

one challenge is that the subharmonics are heavily influenced by the structure itself, so sitting on a lossy riser or floor will give more of an effect than being on a concrete slab.
post #338 of 1882
Quote:
Originally Posted by dominguez1 View Post

4 AE15H drivers appropriately powered would = 2.8SI.
 
No data-bass measurements on the SB13, however I did find this link: http://www.hometheatershack.com/forums/sub-zone-subwoofer-testing/62090-svsound-sb13-ultra.html and below graph:
 
file.php?n=9495
 
Based on this, the SB13 would be around 96db at 16hz, or .8SI
 
So, here are your scores:
 
1750 / 2.8SI = 625@10hz
1750 / (2.8 + 1.6) = 398@16hz
 
As far as your question around how to determine driver not on the list? winisd with some factor to reduce the theoretical max output. You'll have to ask MK how he reduces winisd to get his estimated.

Thanks man. Guess I need to add more woofage. Who needs furniture in a family room anyhow. smile.gif

I think that SB16 number is high btw, 96db at 16hz that is. I think or thought it was 96-98 at 20HZ (2M GP) from some old conversations with Ed way back when.
post #339 of 1882
or maybe go back to a ported design, perhaps with a tuning around 17hz or so. that would give you about +10db relative to sealed around the tuning frequency in exchange for the 10hz stuff and below.
post #340 of 1882
Over at audioholics there is a review on the sb13. they claim to add 6db to the sb12 numbers and that will get you close.

The sb12 puts out 87.7db @ 16hz, add 6db and your lookin at 93.7db for the sb13


http://forums.audioholics.com/forums/subwoofers/81423-pbcs-svsound-sb13-ultra-user-review.html
post #341 of 1882
My living room is about 14.5 x 14.5 x 7 = 1472

My dining room is connected and wide open so that's another 700 cubes.

So about 2172 all day divided by 4 Daytons at .9 @ 16hz yields: 2172/3.6 = 603.

I cannot imagine even tolerating more output in the room and I rarely get anywhere near the limits with anything in the first place, so I don't think I'll be joining the 5 star club anytime soon.

James
Edited by mastermaybe - 9/23/13 at 12:27pm
post #342 of 1882
Quote:
Originally Posted by mastermaybe View Post


I cannot imagine even tolerating more output in the room and I rarely get anywhere near the limits with anything in the first place

James

I have found I can always tolerate (errr I mean WANT) more in the 15-25hz region (I may have mentioned this already in this thread because I post too much and loose track of what I've posted where smile.gif ), that bass that shakes the crap out of you and the couch but isn't very loud at all so the ears don't mind it at all. I recently built a riser for the back row and that 15-25hz bass shakes me significantly MORE on the riser - but still, hehe, I wouldn't mind a little more. Yeah it's a sickness....

However, bass above 30hz - i have more than I want or need. I don't need to go completely deaf.

So, i run ahouse curve for movies and crank the subs nice and hot and that combination takes a ton of power and drivers - well, at least in a sealed sub configuration it does.
post #343 of 1882
^ the ultra low stuff actually does more damage than it's worth in my place. I did a 15 hz tone for a laugh a few weeks ago and I lost the wife's glass cake stand after a 6 foot fall- guess that's what she gets for putting it up on the refrigerator. I felt like a juvenile idiot...and deservedly so.

Movies- even the most "bassy"- rarely see stuff that low for any amount of time so when you play it back for 10-15 seconds you re-realize just how potentially damaging it is at upper levels.


James
Edited by mastermaybe - 9/23/13 at 12:17pm
post #344 of 1882
Quote:
Originally Posted by mastermaybe View Post

^ the ultra low stuff actually does more damage than it's worth in my place. I did a 17.5hz tone for a laugh a few weeks ago and I lost the wife's glass cake stand after a 6 foot fall...guess that's what she gets for putting it up on the refrigerator.


James

I hear you, I did break an antique plate on the level above my room that was sitting on the piano. Since then no incidents, so I think I'm good. I really only crank it up to stupid levels once or twice a month.
post #345 of 1882
Quote:
Originally Posted by mastermaybe View Post

My living room is about 14.5 x 14.5 x 7 = 1472

My dining room is connected and wide open so that's another 700 cubes.

So about 2172 all day divided by 4 Daytons at .9 @ 16hz yields: 2172/3.6 = 603.

I cannot imagine even tolerating more output in the room and I rarely get anywhere near the limits with anything in the first place, so I don't think I'll ever be joining the 5 star club anytime soon.

James

Actually you are correct. Half of my old system was enough for reference viewing to 5hz. I have been stuck on a price point for a while now and just keep trading woofers at the same price point.
post #346 of 1882
Yep, I think I'm prolly at a bit of an AV crossroads at this point...I just don't think I can justify the time, space and cost of pushing anything any further right now. That, and the thrill of new gear is kinda wearing thin on me for some reason...although I DID just get a new blu ray player last week, lol (yeah, but I went without one for 4 months!).

Perhaps again sometime down the road in a new (read: LARGER), dedicated space, but outside of moving to an AVR/PREPRO that does DTS NEO X there's really not much on my radar...other than actually enjoying new movies and music more often that I currently do.

You know, why most people get into this stuff in the first place, lol. tongue.gifbiggrin.gif

James
post #347 of 1882
Thread Starter 
Quote:
Originally Posted by pbc View Post


Thanks man. Guess I need to add more woofage. Who needs furniture in a family room anyhow. smile.gif

I think that SB16 number is high btw, 96db at 16hz that is. I think or thought it was 96-98 at 20HZ (2M GP) from some old conversations with Ed way back when.

 

 

Quote:
Originally Posted by basshead81 View Post

Over at audioholics there is a review on the sb13. they claim to add 6db to the sb12 numbers and that will get you close.

The sb12 puts out 87.7db @ 16hz, add 6db and your lookin at 93.7db for the sb13


http://forums.audioholics.com/forums/subwoofers/81423-pbcs-svsound-sb13-ultra-user-review.html

 

Good call guys!

 
Bass, thanks for the link! I've added the SVS SB13-Ultra to the estimated chart as a result.
post #348 of 1882
Thread Starter 

Post 1 - Estimated SI Conversion Chart Updated

 

Post 2 - Member scores updated

  • Note: qguy's score updated to reflect new Rythmik F15 estimate. Still keeps him at 3 Stars

 

Keep posting scores guys! We now have PSA, HSU, Rythmik, Seaton, and JTR SI conversions available.

 

I'd like to get more info on 3.5 star systems. I'm thinking that this could be the general category for Reference Output at 20hz, but need to get a larger sample of what HT Rooms look like that are in this category.


Edited by dominguez1 - 9/23/13 at 5:31pm
post #349 of 1882
Quote:
Originally Posted by dominguez1 View Post

Small rooms are great, aren't they?

Curious, where did you get your information for yours subs? What output did you use? i will update my list!

For my Occam Audio I just looked at the chart and and what other really small subs were contributing and used that number, so 0.1. Maybe I should have skipped it altogether and just modeled the SVS at 16 HZ. The number would not really change much. I would still be in 4 stars. But I found it did really add a very positive experience to the ULF scenes than just the SVS.

The SVS I used the number from landshark1 calculations (-3 from ultra). So only using the SVS I get.
1456/1.8 = 808 @ 16Hz

I keep thinking I want some sealed subs using room gain but I looking at the chart it is amazing that I would need almost 2 SI to equal my one SVS PC 12 Plus.
Edited by christmclean - 9/23/13 at 7:22pm
post #350 of 1882
Thread Starter 
Quote:
Originally Posted by christmclean View Post


For my Occam Audio I just looked at the chart and and what other really small subs were contributing and used that number, so 0.1. Maybe I should have skipped it altogether and just modeled the SVS at 16 HZ. The number would not really change much. I would still be in 4 stars. But I found it did really add a very positive experience to the ULF scenes than just the SVS.

The SVS I used the number from landshark1 calculations (-3 from ultra). So only using the SVS I get.
1456/1.8 = 808 @ 16Hz

I keep thinking I want some sealed subs using room gain but I looking at the chart it is amazing that I would need almost 2 SI to equal my one SVS PC 12 Plus.

 

Gotcha...thanks for reminding me!

 
I will post the SVS PB12-Plus numbers. 3db down does put it at 102.1 at 16hz for the 15hz tune. That is equivalent to 1.6SI.
 
1456/1.6 = 910. Still 4 star!
 
I wouldn't worry about the Occam for this exercise. Great score for just that one sub!
 
SIs would be great, but that's where ported subs really have efficiency and do very well around tune.
post #351 of 1882
Having owned a ported SVS sub and having heard the svs ultra 13 subs on multiple occasions that comparison really surprises me. Subjectively 2 SI's seem to have far more output than the ultra 13, but like I say that is subjective.

2 SI's have a bit more output than a single Submersive and comparing a Submersive to a ultra 13 would not be a fair fight.
post #352 of 1882
Carp only at tune, above and below it is lights out!
post #353 of 1882
I think this is why adding the small 10 inch CSS SDX sub seems like it adds a lot more output as it does it above tune and of course adds to the smoothing. I was surprised that the 12 inch SVS had so much more output than an 18. Interesting on the comment of above and below tuning as the SVS measure so flat.
post #354 of 1882
Quote:
Originally Posted by carp View Post

2 SI's have a bit more output than a single Submersive and comparing a Submersive to a ultra 13 would not be a fair fight.
Apples and oranges. Around tune, you'd need a boatload of displacement to match the PB13; the SVS can deliver a rough 2-1 advantage over the Funk 18.0 at 16Hz and 20Hz, which has similar displacement and amplification to the SubM (which runs a pair of customized Eminence LAB15s AFAIK). Of course, from 50Hz on up and 16Hz on down, the situation reverses with the Funk having a huge advantage.
post #355 of 1882
Reading the thread over and over I am wondering where you got the numbers for the F25. You have it up 4.5dB at 20hz from the F15HP, and the F15HP down 8dB from the FV15HP. Are these numbers through testing? If not, doesn't the Rythmik site list the F25 as 1dB less than the FV15HP at 20Hz and 4dB more than the F15HP? Using your numbers there is a 3.5dB spread between the FV15HP and the F25.

Just wondering...
post #356 of 1882
Thread Starter 
Quote:
Originally Posted by willscary View Post

Reading the thread over and over I am wondering where you got the numbers for the F25. You have it up 4.5dB at 20hz from the F15HP, and the F15HP down 8dB from the FV15HP. Are these numbers through testing? If not, doesn't the Rythmik site list the F25 as 1dB less than the FV15HP at 20Hz and 4dB more than the F15HP? Using your numbers there is a 3.5dB spread between the FV15HP and the F25.

Just wondering...

 

To be consistent as possible with the other estimates, I extrapolated the F15HP based on the measurements of the FV15HP on data-bass, as well as how typically ported designs and sealed designs (using same amp and driver) differ at tune. Look at this post to see the details. Also look at the SVS PB12 and SB12 results on data-bass. Same driver and amp, but different designs.

 

Also, if I were to use the information from the Rythmik site, that would put the F15HP at 103db @ 20hz. This output doesn't seem accurate when you look at other sealed designs that have similar output. For example, if it were 103db, it would be greater than or equal to the output of the following subs:

  • Funk Audio, FW18.0 (18in)
  • eD A7S-450 (18in)
  • Epik Empire (dual 15's)
  • Velodyne DD18 (18in)

 

I'm a Rythmik owner and big fan, but I wouldn't expect the Rythmik 15in driver can have the same or more output then the above. The displacement is just not there compared to the above.

 

As for the F25, it's basically two F15HP's but with less power. So instead of being 6dbs up with 2x power and displacement, I just estimated 4.5db instead.

post #357 of 1882
Quote:
Originally Posted by basshead81 View Post

Over at audioholics there is a review on the sb13. they claim to add 6db to the sb12 numbers and that will get you close.

The sb12 puts out 87.7db @ 16hz, add 6db and your lookin at 93.7db for the sb13


http://forums.audioholics.com/forums/subwoofers/81423-pbcs-svsound-sb13-ultra-user-review.html

Humorous. I wrote that review but forgot I had quoted Ed in it re the CEA numbers. Must be getting old! smile.gif.
post #358 of 1882
Thread Starter 

1st Post updated - added estimate for SVS PB12-Plus

2nd post updated - member scores

 

Any other subs not on the list that you would like to see estimated? Other DIY drivers?

post #359 of 1882
Quote:
Originally Posted by dominguez1 View Post

Other DIY drivers?
I'm in the process of building four sealed 3cuft cabinets for Dayton Audio UM15-22. I'd love to have a way to compare, but I don't think I could figure out how to work the numbers myself - though I will be trying to get some ground plane measurements after I finish (several weeks).
post #360 of 1882
Thread Starter 
Quote:
Originally Posted by HopefulFred View Post

I'm in the process of building four sealed 3cuft cabinets for Dayton Audio UM15-22. I'd love to have a way to compare, but I don't think I could figure out how to work the numbers myself - though I will be trying to get some ground plane measurements after I finish (several weeks).
For DIY, I'm going to have to count on my winisd expert...mk, can you help out?
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