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Thread: Upgrade to F18, or second LV12R?

  1. #31
    Join Date
    Dec 2016
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    Central NC
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    Default Re: Upgrade to F18, or second LV12R?

    Quote Originally Posted by kdaq View Post
    ...there's a gut feeling that I'm less likely to have buyer's remorse from an F18 than other options.
    The only times I've had buyers remorse is when I've spent too much and bought more capability than I actually needed or used. The remorse was that I could have used that money to improve other things.

    The problem with the diminishing returns curve is determining where you are on it. If you're on the straight line section, spending the extra money buys you a lot of return. If you're on the shoulder of the curve, spending the extra money buys you very little.

    Alternatively, some people get a lot out of having the biggest pickup truck in the neighborhood. Not that they need it. Not that they use it. Just that it's bigger than everyone else's truck. I'm not saying this is bad. I'm just saying you'll benefit in the long run if you can define what you're really after.
    "If it sounds good, it is good." -- Duke Ellington

  2. #32
    Join Date
    Apr 2014
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    455

    Default Re: Upgrade to F18, or second LV12R?

    Quote Originally Posted by Bruce Watson View Post
    The problem with the diminishing returns curve is determining where you are on it. If you're on the straight line section, spending the extra money buys you a lot of return. If you're on the shoulder of the curve, spending the extra money buys you very little.

    I 100% agree with this. This is quite difficult to determine with most things. But, subwoofers are actually one of the easier things to nail down though, especially if kdaq is considering the F18, which was measured over on data-bass:

    http://data-bass.com/data?page=system&id=145&mset=171

    First, sit down in your primary seat with an action movie and adjust the volume as loud as you would possible go and watch the entire movie. Some people might crank up the volume if they are just watching one fun scene, but they aren't likely to keep it uncomfortably high for an entire movie. If your receiver has Audyssey or some other room eq and has the relative volume displayed for the volume, then you should have a pretty good idea of how loud this is. If you are listening at -15 dB, then this means that on average you are listening at 75 - 15 = 60 dB, with peaks in the channels to be as loud as 60 + 20 = 80 dB and peaks in the LFE (or subwoofer) as much as 90 dB. (This works for most movies as they were mastered for the home at 75 dB average, but some might be 85 dB. Check a few movies just to be sure.) If your receiver doesn't have these features, then pick up an SPL meter and measure when you are watching the movie for a few minutes to get an idea. If you have Audyssey with Dynamic EQ, then it may be boosting the LFE as much as 5 dB. Not with - 15 dB, because I think that 60 dB in the bass is considered audible and it isn't likely to be boosted. If you also boosted the bass after running Audyssey, then also keep in mind what that was. Say that you raised the gain in the subwoofer by 5 dB. This means that you want your subwoofer to be able to play as loud as 90 + 5 + 5 = 100 dB.

    Now click on the measurements for the F18 above from data-bass, select the static graphs tab and look for the F18 CEA 2010 in room measurements. You can see that you can easily hit much more than 100 dB, if needed. Many have said that we can't hear as much as 20% THD from 80 Hz and below, so you are likely even okay there. Some argue that they want distortion to be lower than 20%. At 16 Hz you are really close to 20% distortion and the 3rd order harmonic is the big contribution there. This means that if you hit close to 100 to 103 dB at 16 Hz you will get distortion showing up at around 48 Hz, which is audible. Keep in mind that this is only with an instantaneous peak to an explosion or something else really loud for just a split second. Does that bother you? Is that split second of possibly less distortion worth $500 to $800 more for your subwoofer? This is what Bruce was talking about, as far as diminishing returns. Would you be okay just gently rolling off the bass below 20 Hz, with a toggle switch on the Rythmik amplifier, to still get the feeling of 16 Hz but reduce it a slight bit and the distortion that might be accompanying it?

    Say that you only would listen at -20 dB at most and you don't boost the LFE channel at all, so really you need 10 dB less that we were even discussing as the maximum, or 90 dB. In this case you can can go over to the Rythmik homepage

    http://www.rythmikaudio.com/

    and look at the output comparison at 20 Hz. So you could step down 10 dB in output from the F18, then you are in the range of the L12 or F12, with the output probably being just fine. If you want to play things safe maybe you step up 5 dB to the LVX12, or actually getting just the second LVR12 because you will get an extra 3 dB just putting it in the room with your first LVR12 and it is 2.5 dB above the F12, which is around 5 dB.
    Last edited by N Boros; 01-30-2018 at 09:37 AM.

  3. #33
    Join Date
    Dec 2013
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    360

    Default Re: Upgrade to F18, or second LV12R?

    Quote Originally Posted by N Boros View Post
    No problem. Sorry for the confusion.

    No the price hasn’t yet been announced. Over in the AVS thread they have said early spring for a release date. And that Josh Ricci will get one to measure in the middle of the summer. I think that the price will be close to the F25, but maybe slightly more money because of the larger amplifier. Due to the smaller form factor that allows shipping via traditional methods and not freight, the prices might come out really close. I’m just guessing though.

    The performance of the F25 is higher, but Rythmik lists it as only a 1.5 dB advantage at 20 Hz. If they remain that close throughout the frequency band, then really they are pretty close. Who knows, maybe the F25 pulls ahead at higher frequencies, where it would be audible.
    Ya, I'm just guessing that the G25 will gain a couple more dB in the upper bass. If you compare the FV15 to the FV18, the FV18 has a 3dB lead at 20hz. At 31.5hz, however, the difference is only 1dB, and above 40hz they are basically even. I think perhaps the 15 inch driver has a higher sensitivity which allows it to excel in the upper bass, where subs tend to be more amplifier limited as opposed to excursion limited.

  4. #34
    Join Date
    Apr 2014
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    455

    Default Re: Upgrade to F18, or second LV12R?

    Quote Originally Posted by mikesiskav View Post
    Ya, I'm just guessing that the G25 will gain a couple more dB in the upper bass. If you compare the FV15 to the FV18, the FV18 has a 3dB lead at 20hz. At 31.5hz, however, the difference is only 1dB, and above 40hz they are basically even. I think perhaps the 15 inch driver has a higher sensitivity which allows it to excel in the upper bass, where subs tend to be more amplifier limited as opposed to excursion limited.
    Good point about the sensitivity of the 15 inch driver. You may be right.

    I was shocked when I looked at the difference in output for the FV15HP with one port open vs the FV18 with two ports open. It isn't until you get about 25 Hz and below (looking at the CEA 2010 burst measurements) that the FV18 pulls ahead of the FV15HP, by about 3 dB as you mentioned. But, what is interesting is when you look at the difference in the distortion. Now, if I am reading things correctly, Josh left the limiter off with the FV15HP, but he left it on with the FV18, unfortunately. Because now I wonder how much of this lower distortion can be attributed to the limiter being left on? How much can be attributed to a 15 inch versus an 18 inch driver? How much can be attributed to maybe Brian dialing in the limiter a little bit better than he did before (I'm not saying that he did anything bad before, but it as been a number of years since the FV15HP was released and people improve upon things that they did previously.)

    We can remove the variable of the limiter off with the FV15HP and on with the FV18, yet still compare the 15 and 18 inch drivers. Just look at the FV25HP vs the FV18. Notice how again, the FV18 when pushed with these bursts close to its limits, remains more composed in terms of lower THD, whereas the FV25HP is a little less composed. Yes, the FV25HP has quite a bit more output. But, I'm thinking that perhaps the 18 inch driver has something to do with helping it remain more composed. Plus Josh said this about the FV18, when he is commenting on his measurements:

    "The maximum output at the bands above 20Hz was limited by the amplifier and limiter. At 20Hz and below the FV18 would produce about 1dB greater output in the 16Hz tuning, but not while passing the distortion and noise thresholds."

    So even with the limiter off on the FV18, you don't get much more output, at the expense of much greater THD.
    Last edited by N Boros; 01-30-2018 at 12:35 PM.

  5. #35
    Join Date
    Aug 2003
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    7,027

    Default Re: Upgrade to F18, or second LV12R?

    I just want to say I love my F15HP.
    -curtis

  6. #36
    Join Date
    Dec 2013
    Posts
    360

    Default Re: Upgrade to F18, or second LV12R?

    Quote Originally Posted by curtis View Post
    I just want to say I love my F15HP.
    It's a great sub for sure. Although it's fun to talk about these powerful subs, the reality for me, is that I have more subwoofer than I need right now. And I'm sure my neighbors would agree.

  7. #37
    Join Date
    Jun 2016
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    13

    Default Re: Upgrade to F18, or second LV12R?

    Little late to the party but two subs are SO much better than a single one.

  8. #38
    Join Date
    Sep 2015
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    3

    Default Re: Upgrade to F18, or second LV12R?

    Quote Originally Posted by kongar View Post
    Little late to the party but two subs are SO much better than a single one.
    I am looking to add a 2nd sub to my single F25 sealed (one box, two 15s). I would like to step up to the F18 (single sealed 18). Is it ok to mix and match subs? Will it give me the same effect that I've been reading about where multiple swarms of subs greatly enhances the experience?

  9. #39
    Join Date
    Jun 2016
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    13

    Default Re: Upgrade to F18, or second LV12R?

    I feel identical subs are the way to go. Mismatched subs can and probably do work well for many people - but I think you’re adding complexity to the room dynamics in this case.

  10. #40
    Join Date
    Oct 2010
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    51

    Default Re: Upgrade to F18, or second LV12R?

    Oh wow, I don't think I ever posted here about what I ended up doing, did I? In November of 2018 I got the F18!

    At first I wasn't sure about it. My basement is carpet on concrete, and I put the sub without feet in a corner (I have no flexibility in placement unfortunately). It rattled everything like crazy! Next I put it on its rubber feet, and this seemed to help the rattling. The accuracy was fantastic, but I was missing tactile response. Eventually I tried the sub without feet again, but with one difference: I pointed the driver away from the wall and out into the room. That did the trick! The rattling went away, and the TR improved.

    I recently also upgraded my mains from Sierra-2 to Sierra-2EX. These have what I perceive as improved punch or slam (with only a touch of warmth over neutral), and the whole system really sounds phenomenal together.

    This setup uses XT32 room correction, but pretty sure I would benefit from a second sub and/or some DSP correction for the sub specifically. It's a bit of work though, and I'm just really enjoying the setup as it is right now. No regrets!

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