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post #1081 of 2101 Old 12-07-2013, 05:52 PM
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Originally Posted by BeeMan458 View Post

You'll have to forgive some of us but the FV15HPs are the best we can afford and we live our pathetic lives vicariously though those who can afford better are more resourceful.

Hate to pi$$ on the snark but my system costs less than 3X the FV15HPs, so I fixed your post. smile.gif
steve nn and nube like this.
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post #1082 of 2101 Old 12-07-2013, 05:59 PM
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You guys talking about multiples are missing the boat by a wide margin. The FV15HP is a phenomenal sub at an extraordinarily good price, but it cannot work magic or change the laws of physics, as BFM, Ricci, bosso and I are all saying regarding its chuffing/compression. wink.gif

Adding more underported subs doesn't mask or reduce or eliminate the chuffing/compression, it just increases the relative SPL you'll reach before chuffing/compression occurs: +3dB for non-colocated subs, +6dB for stacked (colocated) subs. The point you can hear chuffing, or at any point where the sub changes its output characteristics noticeably, will be the point below which you want to keep your volume levels. It's for this reason that I simply won't accept that the FV15HP is equal to almost 2 sealed 24mm Xmax 18" subs. No way, no how can that little 15 with a 3" port maintain its output characteristics (no chuffing or compression) while producing output at 2x that of the sealed 18" with more xmax.

Additionally, the problem is, if you want to run in 1 port mode, you're gonna run into a lot of movies that will make the underported subs chuff. There are four or five movies released or releasing this quarter that will do it, and probably 15 or more for the entire year.
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post #1083 of 2101 Old 12-07-2013, 06:03 PM
 
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Originally Posted by bossobass View Post

Hate to pi$$ on the snark but my system costs less than 3X the FV15HPs, so I fixed your post. smile.gif

Not being snarky because I'm being honest and FWIW, I'm comfortable with being an underachiever. Nice to read you're able to purchase a system that's less than 3X the FV15HPs. Myself? I work hard at doing nothing all day.

How much are BossoBass subs if bought by the average Joe on the streets?
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post #1084 of 2101 Old 12-07-2013, 06:06 PM
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Yes, Brian D is an engineer but I have been wondering why he didn't engineer the bigger ports for his FV15? Perhaps bigger port reduces extension and most of us do not listen at the level causing the port to chuff?
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post #1085 of 2101 Old 12-07-2013, 06:08 PM
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Originally Posted by BeeMan458 View Post

Myself? I work hard at doing nothing all day.
except posting here right? Lol smile.gif
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post #1086 of 2101 Old 12-07-2013, 06:16 PM
 
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Originally Posted by nube View Post

Adding more underported subs doesn't mask or reduce or eliminate the chuffing/compression, it just increases the relative SPL you'll reach before chuffing/compression occurs:

Besides smoothing room modes, that's the idea behind adding additional subwoofers. As subs are added, the left side of the graph is lifted and each subwoofer has to perform, that much less to achieve a given expected performance. The single flaw that I find in this diabolical plan, I have to pay for all the extra subwoofers. Well, that and after 10Hz, the FV15HP drops like a stone on a breezeless day.

If anybody wants to give us the money, I'd be happy to upgrade to a pair of S2s and a couple of dedicated 30A wall plugs.

-
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post #1087 of 2101 Old 12-07-2013, 06:24 PM
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Quote:
Originally Posted by nube View Post

You guys talking about multiples are missing the boat by a wide margin. The FV15HP is a phenomenal sub at an extraordinarily good price, but it cannot work magic or change the laws of physics, as BFM, Ricci, bosso and I are all saying regarding its chuffing/compression. wink.gif

Adding more underported subs doesn't mask or reduce or eliminate the chuffing/compression, it just increases the relative SPL you'll reach before chuffing/compression occurs: +3dB for non-colocated subs, +6dB for stacked (colocated) subs. The point you can hear chuffing, or at any point where the sub changes its output characteristics noticeably, will be the point below which you want to keep your volume levels. It's for this reason that I simply won't accept that the FV15HP is equal to almost 2 sealed 24mm Xmax 18" subs. No way, no how can that little 15 with a 3" port maintain its output characteristics (no chuffing or compression) while producing output at 2x that of the sealed 18" with more xmax.

Additionally, the problem is, if you want to run in 1 port mode, you're gonna run into a lot of movies that will make the underported subs chuff. There are four or five movies released or releasing this quarter that will do it, and probably 15 or more for the entire year.

I am not missing anything...Dual FV15HP's will be able to play the same level of a single and some with less excursion, which equals less port chuffing. I didnt say both subs would not chuffed when pushed to thier limits. The whole point for multiples is a smoother response and cleaner output. Several FV15HP owners have stated chuffing is not a huge issue. Also Note the FV15HP was tested with the limiter off.
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post #1088 of 2101 Old 12-07-2013, 08:25 PM - Thread Starter
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Quote:
Originally Posted by nube View Post

It's for this reason that I simply won't accept that the FV15HP is equal to almost 2 sealed 24mm Xmax 18" subs. No way, no how can that little 15 with a 3" port maintain its output characteristics (no chuffing or compression) while producing output at 2x that of the sealed 18" with more xmax.

Additionally, the problem is, if you want to run in 1 port mode, you're gonna run into a lot of movies that will make the underported subs chuff. There are four or five movies released or releasing this quarter that will do it, and probably 15 or more for the entire year.

nube, I'm pretty sure you know this, but I'll mention it anyway: The SI equivalent calculation is based on CEA-2010 Max Burst data as measured by Josh, and posted on data-bass.com. The metric you're referring to is the FV15HP 12.5hz output versus the SI's output at that same frequency.

 

Based on that single metric alone, and at the frequency, it does take 1.9 SIs to reproduce the same CEA-2010 burst output as the FV15HP. There is no subjectivity to it. It is a math based derivative and a fact.

 

Your point is clear though when looking beyond this single lens: both subs driven and maximum levels, the SI will not have any port noise. Advantage sealed and the SI. Perhaps this is lost by some just looking at max burst data and/or using the ULF calculator. However, I don't recall anyone comparing the FV15HP to 2 SIs and claiming the FV15HP is equal at creating ULF (as you seem to be positioning it).

 

Regarding the FV15HP port noise, in practice and in my room, I've found port noise is largely inaudible because it is either masked by other content, positioning in the room, or simply not pushed to the levels that would cause it. Granted, I also have a pair of FTW21s, so that certainly helps the situation. I've also found that in my room, ported subs (even my LFM1-EXs) did a much better job at shaking the couch than the FTW21s and why I ultimately went with a ported/sealed mix...but that is for another discussion down the road. :)

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post #1089 of 2101 Old 12-07-2013, 09:17 PM
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Originally Posted by Luke Kamp View Post



Take the 21SW152-4 25Hz Ported subwoofer for instance. It has a passing 16hz of 96.7 dB, however it is 33.5 dB down from 63 hz. I don't see the point in using them for ULF or a score of 16 hz for this thread no matter how many are being used. It's just my opinion and you can do it however you like. smile.gif

Just chiming in b/c this did start with beeman suggesting he would be getting 10hz useable and posted a graph with 10hz 18 dB down to show that it will do 10 hz if you have enough.

basshead suggested the same.
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post #1090 of 2101 Old 12-07-2013, 09:32 PM
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Quote:
Originally Posted by BeeMan458 View Post

Quote:
Originally Posted by nube View Post

Adding more underported subs doesn't mask or reduce or eliminate the chuffing/compression, it just increases the relative SPL you'll reach before chuffing/compression occurs:

Besides smoothing room modes, that's the idea behind adding additional subwoofers. As subs are added, the left side of the graph is lifted and each subwoofer has to perform, that much less to achieve a given expected performance. The single flaw that I find in this diabolical plan, I have to pay for all the extra subwoofers. Well, that and after 10Hz, the FV15HP drops like a stone on a breezeless day.

If anybody wants to give us the money, I'd be happy to upgrade to a pair of S2s and a couple of dedicated 30A wall plugs.

-

Your not going to get 10hz. geezus
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post #1091 of 2101 Old 12-07-2013, 10:06 PM
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Quote:
Originally Posted by BeeMan458 View Post

If anybody wants to give us the money, I'd be happy to upgrade to a pair of S2s and a couple of dedicated 30A wall plugs.

-

You could easily run a pair of Cap S2's off of a single 20amp circuit wink.gif

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post #1092 of 2101 Old 12-08-2013, 03:41 AM
 
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Originally Posted by jbrown15 View Post

You could easily run a pair of Cap S2's off of a single 20amp circuit wink.gif

Sorry. If somebody is giving me the money, I expect to be given sufficient monies to install what "I" consider to be proper electric service. This isn't an argument, nor was my comment intended to take into consideration, what others might want to do. You're happy with a single 20A dedicated breaker and I would be happy with two dedicated 30A circuits. I've yet to understand why every disagreed upon comment has to be turned into a; you're wrong and I'm right type of interaction.

If you want to run 8000W peak, RMS (67A), off a single 20A (120V) breaker, I encourage you to go with what makes you feel all warm and fuzzy inside but all unspent monies must be returned to the benefactor.

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post #1093 of 2101 Old 12-08-2013, 05:40 AM
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This is interesting for a whole lot of reasons.

http://www.avsforum.com/t/1504343/2x-18-lms-ultra-5400-in-27-cubic-foot-15hz-vented-enclosure-build-thread

Notnyt is trying out a huge ported enclosure with two lms 5400 tuned to 15hz. If he likes it he will build three more. Some of the ideas and numbers are certainly applicable to recent discussion. wink.gif

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post #1094 of 2101 Old 12-08-2013, 06:50 AM
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Originally Posted by sputter1 View Post

basshead suggested the same.

I did not suggest the same...I said Beeman might see 10hz extension but not anywhere near reference. I actually said to focus on 12.5hz on up and if/any extension below that it is a bonus.
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post #1095 of 2101 Old 12-08-2013, 07:07 AM
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Dom

Can you update me on the list now that I have (this week) 2 xs30's in my room. It brings me to 3.5 @ 10hz and 4.0 above

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post #1096 of 2101 Old 12-08-2013, 07:09 AM
 
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Originally Posted by sputter1 View Post

Your not going to get 10hz. geezus

Then you don't have anything to worry about. How about you guys stop tearing up this thread with your worries about how our pending system is going perform. It's going do what it's going do and no more but what ever it chooses to do, is not worth ruining this thread over.
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post #1097 of 2101 Old 12-08-2013, 07:15 AM
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Originally Posted by BeeMan458 View Post

Then you don't have anything to worry about. How about you guys stop tearing up this thread with your worries about how our pending system is going perform. It's going do what it's going do and no more but what ever it chooses to do, is not worth ruining this thread over.

+1 its as if they WANT you to regret your purchase...which in no way you should

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post #1098 of 2101 Old 12-08-2013, 07:20 AM
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Originally Posted by basshead81 View Post

There is nothing to worry about Beeman. Those FV15HP's from 10-100hz are going to make your old subs sound like A.M. radio. When you get solid < 15hz output your chair or couch will feel like a message chair set to a slow pulse. Its pretty awsome!! During the WWZ grenade scene my couch started to wobble, yes you could visually see it.

^^--- here.
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post #1099 of 2101 Old 12-08-2013, 07:22 AM
 
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Thanks! What ever these two expected FV15HPs choose to put out, based on Brian's design efforts, room gain and EQ'g efforts, I know I'm going be blown away. Yes, I understand, I get it, what ever two or three FV15HPs are capable of outputting, is empirically finite.

If some guy tells me he can fly. I don't argue. I say something like "You can? That's great." And I wish him a safe trip. This thread of dominguez1 is a wonderfully helpful thread to folks like me. That's code for; I'm a flaming ignorant. I hope participants will get back to treating this thread with the deserved respect it's due.

(my apologies to dominguez1 for having to read and watch this valued thread of his, degenerate the way it has)

-
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post #1100 of 2101 Old 12-08-2013, 07:37 AM
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dominguez1, I appreciate what you've done with this thread and I think it's really very useful. I'm not trying to invalidate all the good work you've done here, and I couldn't if I tried. smile.gif Because these scores are a reasoned estimate, I think there's enough reasonable objection that the FV15HP's rating is inaccurate, and should be revised downward significantly where it chuffs at 12.5Hz and 16Hz, or not rated at those frequencies at all because they aren't usable at the output quoted for the equivalency without significant negative externalities.

Also, dominguez, as to "tactile feeling," or one sub configuration doing a better job at shaking/resonating, it has nothing to do with the type of sub you have. It's just a function of output at the resonant frequency of your materials/floor/walls/couch/whatever is shaking.

In a room that remains constant, it is not possible for your room to prefer shaking/resonating for ported over shaking/resonating for sealed, so let's not muddy the waters for the nubes. wink.gif It's not at all about the sub's configuration, not even one iota. It's solely about total overall output at the frequency(s) that resonate your materials/floor/walls/couch/whatever is shaking.

Also, to BeeMan, I'm not sure how you missed this on Rythmik's FV15HP webpage, but it clearly states:
Quote:
FV15HP uses our new high power H600PEQ3 servo amplifier and DS1510 driver. DS1510 features anodized aluminum cone, a 3" voice coil, and 200 oz magnet. Its linear excursion range has increased to +/- 20mm (from +/-15mm of DS1500). The entire subwoofer is 12lbs heavier. It also comes with grill and the above photo is shown with grill taken off.

I think we can all agree the driver in the FV15HP has 20mm of excursion, hence my desire to simulate ported subs with 20mm useable stroke.

Josh Ricci, in testing the FV15HP, said this about the ports:
Quote:
The FV15HP is medium to large sized for a commercial HT subwoofer with two 3" flared ports and the 15" driver all mounted to the front panel.

which is why I modeled using a single 3" round port. Modeling helped me see the relationship between size and length of ports and the tuning. It's really important to get this right, and keep port air velocity below 26m/s (the point at which chuffing is audible).
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post #1101 of 2101 Old 12-08-2013, 07:50 AM
 
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There's been enough distraction regarding the FV15HP.
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post #1102 of 2101 Old 12-08-2013, 08:02 AM
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Quote:
Originally Posted by sputter1 View Post

^^--- here.

Did you go all the way back to our first posts on this topic? When I posted that, it was in regards to his other subs. I still stand by my statement that from 10-100hz the FV1HP's will outperform his old setup 10 fold. I did not say he would get reference at that frequency, which is what started this debate. I dont think anybody is arguing that 10hz extension is not possible being its only 2.5hz below 2m rms ground plane testing. What is being argued is that they will not hit reference levels(115db @ 10hz)...and I agree.
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post #1103 of 2101 Old 12-08-2013, 08:12 AM
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Quote:
Originally Posted by nube View Post

dominguez1, I appreciate what you've done with this thread and I think it's really very useful. I'm not trying to invalidate all the good work you've done here, and I couldn't if I tried. smile.gif Because these scores are a reasoned estimate, I think there's enough reasonable objection that the FV15HP's rating is inaccurate, and should be revised downward significantly where it chuffs at 12.5Hz and 16Hz, or not rated at those frequencies at all because they aren't usable at the output quoted for the equivalency without significant negative externalities.

Also, dominguez, as to "tactile feeling," or one sub configuration doing a better job at shaking/resonating, it has nothing to do with the type of sub you have. It's just a function of output at the resonant frequency of your materials/floor/walls/couch/whatever is shaking.

In a room that remains constant, it is not possible for your room to prefer shaking/resonating for ported over shaking/resonating for sealed, so let's not muddy the waters for the nubes. wink.gif It's not at all about the sub's configuration, not even one iota. It's solely about total overall output at the frequency(s) that resonate your materials/floor/walls/couch/whatever is shaking.

Also, to BeeMan, I'm not sure how you missed this on Rythmik's FV15HP webpage, but it clearly states:
I think we can all agree the driver in the FV15HP has 20mm of excursion, hence my desire to simulate ported subs with 20mm useable stroke.

Josh Ricci, in testing the FV15HP, said this about the ports:
which is why I modeled using a single 3" round port. Modeling helped me see the relationship between size and length of ports and the tuning. It's really important to get this right, and keep port air velocity below 26m/s (the point at which chuffing is audible).

So you are saying Ricci testing on the FV15HP is wrong needs to be revised? Again the limiter was accidently left off during testing. Turn the sub down a db or 2 and the chuffing will probably go away. Read his review again. It states;

The subwoofer shows a good amount of headroom and very good compression performance from 25Hz on up. Exceptionally good. Unfortunately the single 3" port can't cope with the output of the 15" driver and compresses a lot while also contributing a lot of wind noise at the highest output levels. Still overall headroom and low bass extension are very good.
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post #1104 of 2101 Old 12-08-2013, 08:18 AM
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Please don't put words in my mouth. This is a reasoned, reasonable, and deliberate discussion for the purposes of arriving at a community-endorsed estimate of a sub's equivalence to the SI 18" sub in sealed configuration.

As such, here are Josh Ricci's own words regarding testing of the FV15HP in 1 port mode at the levels used for this equivalency (the highest output levels):
Quote:
The FV15HP operated in 1 port mode exhibited very low extension down effectively to the 14-15Hz range anechoic.
and
Quote:
Unfortunately the single 3" port can't cope with the output of the 15" driver and compresses a lot while also contributing a lot of wind noise at the highest output levels.
and
Quote:
[In 2 ports mode,] the amount of port compression and wind noise is greatly reduced. Overall the headroom is very good and output is useable till 16Hz still. Compression performance is very good above 30hz as is bandwidth uniformity. Overall we feel like the 2 ports open mode is superior to the single port open mode due to the increased vent area and higher overall output above 20Hz.

The tester is telling you the 1 port mode has:
  • Useable output to 14 or 15Hz, not 12.5Hz. This is 1/4 of the 10-20Hz octave. It's not insignificant.
  • Large amounts of compression and chuffing from the single port at high output levels (those used for comparison in this SI equivalency). Why? Because it's underported in extension mode!
  • Less desirability than 2 ports mode because of that compression and chuffing.


I think it is reasonable to listen to the tester's caveats and not overinflate the expectations of the FV15HP to be equivalent to nearly 2 SI 18", because it's not if you consider the negative externalities of chuffing and compression at the output levels used to come at this figure. Precisely because this thread is an estimate of expected output, we should consider those caveats in this equivalency.
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post #1105 of 2101 Old 12-08-2013, 08:28 AM
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Quote:
Originally Posted by nube View Post

Please don't put words in my mouth. This is a reasoned, reasonable, and deliberate discussion for the purposes of arriving at a community-endorsed estimate of a sub's equivalence to the SI 18" sub in sealed configuration.

As such, here are Josh Ricci's own words regarding testing of the FV15HP in 1 port mode at the levels used for this equivalency (the highest output levels):
and
and
The tester is telling you the 1 port mode has:
  • Useable output to 14 or 15Hz, not 12.5Hz. This is 1/4 of the 10-20Hz octave. It's not insignificant.
  • Large amounts of compression and chuffing from the single port at high output levels (those used for comparison in this SI equivalency). Why? Because it's underported in extension mode!
  • Less desirability than 2 ports mode because of that compression and chuffing.


I think it is reasonable to listen to the tester's caveats and not overinflate the expectations of the FV15HP to be equivalent to nearly 2 SI 18", because it's not if you consider the negative externalities of chuffing and compression at the output levels used to come at this figure. We should consider those caveats in this estimate of equivalency.

If the sub put out a passing 98db @ 12.5hz 2m rms, then I dont see how it would not have useful extension down to 12.5hz in room. I think its up to the folks that actually own and have herd the FV15HP to determine if your so called caveats should be considered. From what I have seen reported, port chuffing is not nearly as big of issue as some of you make it out to be.
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post #1106 of 2101 Old 12-08-2013, 08:37 AM
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I found the 1 port sound quality to be better than 2 port, even though 2 port is capable of a bit more output. I guess it depends on your priorities. Interestingly, the change in character was a pretty continuous progression from FV15HP 2 port -> FV15HP 1 port -> F25, with a bit cleaner sound, deeper extension, more detail, but less output at each step.
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post #1107 of 2101 Old 12-08-2013, 08:42 AM
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Relax, guy. smile.gif There's no need to get worked up about this, just because people aren't rushing to press the THANKS button on every back-slapping post. This thread's purpose is an estimate, and there's sound methodology for why the FV15HP's estimate is too high.

This thread uses highest output levels to compare, so that point is moot - please don't bring it up again. This is your +1111 post warning. wink.gif

At the highest output levels of the FV15HP testing, it produced a lot of port chuffing and compression. Those negative externalities are what we want to avoid when considering a sound system. The only way to avoid them with the FV15HP is to not play it as loud, and if it's not as loud, it's not equivalent to as many SI 18" subs. See how that logic flows as reasoning for estimating the equivalency?

Port chuffing is a big issue that speaker designers avoid like the plague, regardless of whether or not you think it's a big deal. In this case, it's likely that the FV15HP produces wind speeds from that port that are 3-4x the audible maximum threshold recommended by speaker designers. That's excessive, no matter whether you think so or not. redface.gif This is also why anecdotes aren't really worthwhile - people tend to overvalue their equipment's strengths, and downlplay its weaknesses, when evaluating. It's just human nature.

As an aside, anecdotal "evidence" is one of the big reasons why Craig Chase has been lambasted here over the last few years. He ignores facts and caters to those who do too. That attitude runs counter to a lot of the people here, especially those involved in objective testing and measurement. Let's not suggest anecdotal accounts as a means to invalidate objectivity, as it doesn't add anything that is apples-to-apples, and likely detracts from the discussion.
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post #1108 of 2101 Old 12-08-2013, 08:56 AM - Thread Starter
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Quote:
Originally Posted by nube View Post

dominguez1, I appreciate what you've done with this thread and I think it's really very useful. I'm not trying to invalidate all the good work you've done here, and I couldn't if I tried. smile.gif Because these scores are a reasoned estimate, I think there's enough reasonable objection that the FV15HP's rating is inaccurate, and should be revised downward significantly where it chuffs at 12.5Hz and 16Hz, or not rated at those frequencies at all because they aren't usable at the output quoted for the equivalency without significant negative externalities.
 

 

 

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Originally Posted by basshead81 View Post


So you are saying Ricci testing on the FV15HP is wrong needs to be revised? Again the limiter was accidently left off during testing. Turn the sub down a db or 2 and the chuffing will probably go away. Read his review again. It states;

The subwoofer shows a good amount of headroom and very good compression performance from 25Hz on up. Exceptionally good. Unfortunately the single 3" port can't cope with the output of the 15" driver and compresses a lot while also contributing a lot of wind noise at the highest output levels. Still overall headroom and low bass extension are very good.

What nube is saying is that he does not agree with the CEA-2010 max burst measurement methodology in the FV15HPs example, because he does not believe it takes into consideration audible port noise. Unfortunately, this is the best metric we have at this point, until Josh's incorporates a new methodology to factor that in his tests if he so chooses.

 

For those that want to eliminate as much port noise as possible, use the 2 port mode. This can also be selected the ULF calculator as well. Nube, instead of re-estimating the 1 port mode, you (and others with the same concern) can just go with the 2 port mode calculation.  

 

Like I said, in practice, port noise in 1 port mode has been largely inaudible in my room and other owners have had similar experiences. Having said that, I personally would never own a completely ported system because it does not have full bandwidth extension as well as the possibility of port noise. (I started with ported and went to sealed for that reason...and then eventually the mix).

 

As for the 10hz claim for the FV15HP, it is not a factor in the ULF score at all, so I think this topic can be dropped. :) 

 

Also remember, this is about comparing HT systems, not necessarily specific sub performance. It's inevitable to do so because that is part of what drives the score (and I'm okay with it as long as it doesn't become a long, drawn out debate), but at the end of the day, 3-6 db difference in output will likely only shift your ULF score by a 1/2 star if that. 

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post #1109 of 2101 Old 12-08-2013, 09:25 AM - Thread Starter
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Originally Posted by nube View Post

Also, dominguez, as to "tactile feeling," or one sub configuration doing a better job at shaking/resonating, it has nothing to do with the type of sub you have. It's just a function of output at the resonant frequency of your materials/floor/walls/couch/whatever is shaking.

In a room that remains constant, it is not possible for your room to prefer shaking/resonating for ported over shaking/resonating for sealed, so let's not muddy the waters for the nubes. wink.gif It's not at all about the sub's configuration, not even one iota. It's solely about total overall output at the frequency(s) that resonate your materials/floor/walls/couch/whatever is shaking.

I would typically agree 100% and that completely makes sense. (And trust me, it pains me to make a statement like that because I'd be the one on the other side saying it was impossible.) However, this is why I wanted to bring it up, because I experienced something different even when trying to match frequency responses. I'm sure there's a reason for why it is counter intuitive in my scenario, but wanted to bring it up here as part of the ULF perception discussion. I'll post more details in the next day or two...

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post #1110 of 2101 Old 12-08-2013, 09:26 AM
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Nice thread!! I have a sealed off 2050 cubic ft. Room. I have 2 fv15hp's ... I come up with a score of 539@12.5 hz .. Is that correct?

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