CEA-2010 Rating LV12r?

[Johnny_Mac_III]

I haven't been able to find a CEA-2010 rating for the LV12r? Do you know what it is rated at 20hz thanks?

[N Boros]

I haven't been able to find a CEA-2010 rating for the LV12r? Do you know what it is rated at 20hz thanks?

I don't know of anyone outside of Rythmik or Ascend who might have measured the LV12R in this way. But, if Brian's measurements on the Rythmik website are accurate, you can extrapolate some if this information from the detailed review of the FV15HP by Josh Ricci.


Here is the info from Rythmik webpage:

"Output comparison

At 20 Hz, our subs vary in their maximum output capability. The output at 20 Hz is shown relative to F12.

F12: 0db (baseline)
F8: -1.5db
LV12R: +2.5db
E15HP: + 3.5db
F15HP: +4db
FV15HP: +9.5db
F25: +8db"


Here are Josh Ricci's measurements of the FV15HP:

http://www.avsforum.com/forum/113-su...t-results.html
http://www.data-bass.com/data?page=system&id=51&mset=50




Ilkka measured the sealed 12" DIY Rythmik sub several years ago:

http://www.hometheatershack.com/foru...ealed-56l.html

These are the only 3rd party measurements of the Rythmik subs that I know of. I don't know how helpful the measurements of the DIY 12" sub is, but it should have at least a little bit more output than the F12. It would be nice if Ricci could get a sealed Rythmik like the F15HP or the F25 to see how they stack up to their ported brother.

[Johnny_Mac_III]

Hey. Thank you for all the info.

It looks like I will be going with the SVS PB 2000. I really wanted something in this price range that could peak at 103 db without any strain whatsoever. The PB 2000 has a sledge amp which is also low distortion and with DSP for accuracy. It gets down pretty deep as well.

I'm sure the F12 is an amazing sub, but maybe just not for me.

[N Boros]

Hey. Thank you for all the info.

It looks like I will be going with the SVS PB 2000. I really wanted something in this price range that could peak at 103 db without any strain whatsoever. The PB 2000 has a sledge amp which is also low distortion and with DSP for accuracy. It gets down pretty deep as well.

I'm sure the F12 is an amazing sub, but maybe just not for me.

The SVS PB 2000 seems to be a good sub for the money. That is a good candidate for the money. Here are the measurements for the PB 12 NSD, which is the model the PB 2000 replaced: http://www.data-bass.com/data?page=system&id=66&mset=71 . The two subs are very close in performance, but SVS was able to get a slight bit lower extension with the PB 2000.

If you haven't yet ordered the SVS sub, other subs you might want to add to your list, that you are researching, are the two new HSU subs: the VTF-3 MK5 HP and the VTF 15H MK2. Those two subs are also in about that same price range and seem to get a tremendous amount of output for the price. If you don't mind the fact that they are quite large subs they are also very good performance for the price.

I'm thinking of upgrading to a couple of subs in the near future, since I moved into a new house with a basement that is just about completely open concept, meaning there is a very large volume to fill. I'm leaning towards the HSU VTF 15H MK2, for the amount of output that you get for the price. It seems to be close in output to the Rythmik FV15HP and even the SVS PB13 Ultra for quite a bit less money.

Good luck.

[luisv]

I'll second your recommendation of the HSU VTF 15H sub... I don't have the MK2 version, but after 3 years of ownership I couldn't be happier.

[Johnny_Mac_III]

The SVS PB 2000 seems to be a good sub for the money. That is a good candidate for the money. Here are the measurements for the PB 12 NSD, which is the model the PB 2000 replaced: http://www.data-bass.com/data?page=system&id=66&mset=71 . The two subs are very close in performance, but SVS was able to get a slight bit lower extension with the PB 2000.

If you haven't yet ordered the SVS sub, other subs you might want to add to your list, that you are researching, are the two new HSU subs: the VTF-3 MK5 HP and the VTF 15H MK2. Those two subs are also in about that same price range and seem to get a tremendous amount of output for the price. If you don't mind the fact that they are quite large subs they are also very good performance for the price.

I'm thinking of upgrading to a couple of subs in the near future, since I moved into a new house with a basement that is just about completely open concept, meaning there is a very large volume to fill. I'm leaning towards the HSU VTF 15H MK2, for the amount of output that you get for the price. It seems to be close in output to the Rythmik FV15HP and even the SVS PB13 Ultra for quite a bit less money.

Good luck.

Thanks. Could you explain the difference between All Time Max avs All Time Minimum?

BecUse I only really need about 103 db including headroom. I need about 75 db without headroom.

[N Boros]

Thanks. Could you explain the difference between All Time Max avs All Time Minimum?

BecUse I only really need about 103 db including headroom. I need about 75 db without headroom.

One of the important graphs you want to look at if you are really interested in clean 103 dB peaks is the "long term output compression" graphs.

Compare those graphs for the SVS PB 12 NSD and the HSU VTF 15H on databass:

http://www.data-bass.com/data?page=system&id=66&mset=71

http://www.data-bass.com/data?page=s...d=100&mset=110

The SVS sub begins to run out of steam at about 105dB, where if much more output is asked for, it just doesn't really play much. The THD is nicely under 10% even up to the 110 dB sweep though. The Hsu sub in 1 port mode doesn't start compressing the output until you get to around 110 dB, but the THD from 27 Hz and below if higher than that of the SVS (though the SVS has already refused to play louder down that low at this level). In 2 port mode the Hsu can even get up to 115 dB before it starts compressing the output and the THD is less than or equal to 10%, as well. But, this is at the expense of having flat extension only down to around 25 Hz.

The transient response to match that of the Ascend speakers is also a factor to consider. In 1 port mode the HSU sub performs very well in this area as the waterfall plots, and group delay measurements show. The SVS sub also performs very well in this area, except below 40 Hz, as shown in the waterfall plots and group delay measurements. Whether this is audible or not, I am not sure, but it is easy to see from the graphs on databass.

Now we were just comparing the older versions of both the SVS and Hsu subs, so you can expect the new models to perform even better. I think Hsu made bigger improvements over its previous model, than SVS made over its previous model though.

To me, if the larger size and weight of the Hsu sub don't scare you off, it seems like a superior sub compared to the SVS sub. Not that the SVS sub is bad in any way for the price. I just think that the Hsu sub is offering more performance in just about every category. It even comes with three different tuning options and all kinds of different adjustments to the frequency response (including the Q adjustment), where the SVS sub doesn't offer these things. The Hsu sub will be about $200 more, but that seems close enough to the SVS sub where it is reasonable to compare them.

But for you, either of the subs will hit 103 dB peaks cleanly (with low distortion) without a problem.

[Johnny_Mac_III]

One of the important graphs you want to look at if you are really interested in clean 103 dB peaks is the "long term output compression" graphs.

Compare those graphs for the SVS PB 12 NSD and the HSU VTF 15H on databass:

http://www.data-bass.com/data?page=system&id=66&mset=71

http://www.data-bass.com/data?page=s...d=100&mset=110

The SVS sub begins to run out of steam at about 105dB, where if much more output is asked for, it just doesn't really play much. The THD is nicely under 10% even up to the 110 dB sweep though. The Hsu sub in 1 port mode doesn't start compressing the output until you get to around 110 dB, but the THD from 27 Hz and below if higher than that of the SVS (though the SVS has already refused to play louder down that low at this level). In 2 port mode the Hsu can even get up to 115 dB before it starts compressing the output and the THD is less than or equal to 10%, as well. But, this is at the expense of having flat extension only down to around 25 Hz.

The transient response to match that of the Ascend speakers is also a factor to consider. In 1 port mode the HSU sub performs very well in this area as the waterfall plots, and group delay measurements show. The SVS sub also performs very well in this area, except below 40 Hz, as shown in the waterfall plots and group delay measurements. Whether this is audible or not, I am not sure, but it is easy to see from the graphs on databass.

Now we were just comparing the older versions of both the SVS and Hsu subs, so you can expect the new models to perform even better. I think Hsu made bigger improvements over its previous model, than SVS made over its previous model though.

To me, if the larger size and weight of the Hsu sub don't scare you off, it seems like a superior sub compared to the SVS sub. Not that the SVS sub is bad in any way for the price. I just think that the Hsu sub is offering more performance in just about every category. It even comes with three different tuning options and all kinds of different adjustments to the frequency response (including the Q adjustment), where the SVS sub doesn't offer these things. The Hsu sub will be about $200 more, but that seems close enough to the SVS sub where it is reasonable to compare them.

But for you, either of the subs will hit 103 dB peaks cleanly (with low distortion) without a problem.

Thanks for all the awesome information. That is an awesome website. Again thanks for taking the time to educate me on what to look for. Have a good one. I'll update to late you know what I ended up getting when tax money gets here

[RythmikAudio]

This is Brian from Rythmik Audio. I think N. Boro provides a good explanation of the plots. But there are a few points that I want to add. Anyway, I need to explain why FV15HP is worth the money we ask for. So bear with me (or even take a grain of salt) for a moment.

First the frequency plot actually shows the VTF-15H has a roll-off of -10db at 20hz for 2 port mode and a roll-off of -9db at 14hz in one port mode. VTF-15H is capable of more than that (it was set to Q=0.3 during measrement). But we need to be careful when we compare plots. When we compare a curve with label of 110db, we cannot assume it is 110db everywhere. I believe Josh (site owner of Databass) uses the output of 50hz as the db number on the label. Why is this important? Becaus when you compare 110db curve from sub A with 110db curve from sub B, we need to check the actual output at the frequency we compare. We cannot assume they both have the same output anywhere. I had explained to Josh that we shouldn't use actual db number to label the curve because the db number is only valid at one frequency point -- 50hz. Very often it will be mis-quoted. In fact this leads to one problem, a sub with early roll-off will artificially measure better, not only in distortion (becasue the output is less), but also in impulse response (a FR roll-off at 40hz will take only half of the time of FR roll-off at 20hz), in almost every area. Just remember someone once said "the best bass is no bass" (I don't want to say who he is as he wasn't thinking clearly when he said it). Ilkka (the reference of our DIY subwoofer) had at one time usedcurve A, B, C, D.. as the label, completely do without numbers exactly for this reason.

Now, the curves from Databass for FV15HP has -3db at 18.7hz in 2 port mode. At 20hz, it has less than 1db roll-off. So first, that is a true deep extension subwoofer. Second any db label on the measurement has a better correlation with the output at 20hz whereas the so-called 110db curve for VTF-15H is more like 100db at 20hz for 2 port mode.

Now when it comes to servo, most people will think it is to reduce distortion simply because that concept is simple to understand. But it goes beyond that. One of the area that servo improves is the linear scalability. Databass site publishes curves from 90db all the way to 110db, it serves a purpose. It wants to see how a sub scales with different input level. So if we have a particular 90db FR curve, we want to see in ideal case that when input increases by 5db, the output will simply have 5db added to 90db FR curve. Same thing if the input increases by 10db, 15db, ..etc. Now the best way to check this linear scalability is we can just use 90db as reference, deduct (5db + 90db curve) from the 95db curve, and deduct (10db + 90db curve) from the 100db curve,...etc and all these plots form a so-called "output compression magnitude plot". If a system is perfectly linearly scalable, all these normalized curves will be on top of one another and be 0db. But in reality, the measurement will inevitably pick up noise in one or two measurements. That can cause it to have deviation on one or two curves. It is important to check the tend. Our FV15HP shows the best output compression curve that any sub can see (even better than Velodyne DD-18). The plot of 1 port mode shows the curves are in an extreme tight range above 30hz. The entire band of curves do move up and down because the noise in the 90db measurement curve has moves every other curves up and down at the same time.

So why is this important? Music is dynamic and constanly changing its signal strength. The ability to maintain linearity throughout the entire signal strength range is the first key to high fidelity. In non-servo, the problem is so serious that engineers just cross their fingers and hope for the best. On the other hand, servo completely solves this problem. Moreover, one reason nonservo subs have these problems is because the voice coil temperature can change after we put in that 100W to 600W power to the voice coil. When the temperature goes up, so is the voice coil resistance and that chokes the amount of current going to the driver even when the amplifier output stays the same. Unortunately voice coil temperature does not cool down instantaneously. That becomes a memory effect. We all see how a pressure on a memory foam will leave an imprint that takes time to recover. Same thing is heating up the voice coil. So why is this important? Same linear scalability needs to apply to time domain as well(vs in the domain of the signal strength as discussed above). If we measure a 90db curve A at time moment 0, we expect the same 90db curve to be repeatable at any other time. This seems to be very easy. But later we will see how much better our servo subs perform. The way to test this is Josh will publish two 90db curves in the "long term output compression" plot. The first 90db curve is what he normally runs. The second 90db curve (labelled as 90db REPEAT) is done as soon as he finishes the highest SPL sweep (after the voice coil heats up). Our sub is the only sub that has those two curves almost identical. It is not because of luck. It is because of servo operation. The problem of memory effect is that if we have notes A, B, C, and D. The sequence of these notes can change the strength of each because the power burnt by each note will affect the output of subsequent notes up to some time. It is a type of distortion. Our subs will sound more realistic because it is linear scalable on both signal and on time. The sequence of notes does not affect the playback strength of each note. You can play ABCD or DCBA and each A will have the same strength. That is the coherance we want.

As for the measurements from home theater shack, we need to add 6db to their numbers to be comparable to the number from Databass because they are measured at difference distance. If I am not mistaken, the former is at 2m whereas the latter is at 1m.

Last, I am not sure if anyone notice that FV15HP decay plots was done down to -35db from the reference and VTF-15H was done only down to -30db from the reference. In shor, the former was plotted with 5db higher resolution. It makes the direct comparison a bit more difficult.

[Johnny_Mac_III]

This is Brian from Rythmik Audio. I think N. Boro provides a good explanation of the plots. But there are a few points that I want to add. Anyway, I need to explain why FV15HP is worth the money we ask for. So bear with me (or even take a grain of salt) for a moment.

First the frequency plot actually shows the VTF-15H has a roll-off of -10db at 20hz for 2 port mode and a roll-off of -9db at 14hz in one port mode. VTF-15H is capable of more than that (it was set to Q=0.3 during measrement). But we need to be careful when we compare plots. When we compare a curve with label of 110db, we cannot assume it is 110db everywhere. I believe Josh (site owner of Databass) uses the output of 50hz as the db number on the label. Why is this important? Becaus when you compare 110db curve from sub A with 110db curve from sub B, we need to check the actual output at the frequency we compare. We cannot assume they both have the same output anywhere. I had explained to Josh that we shouldn't use actual db number to label the curve because the db number is only valid at one frequency point -- 50hz. Very often it will be mis-quoted. In fact this leads to one problem, a sub with early roll-off will artificially measure better, not only in distortion (becasue the output is less), but also in impulse response (a FR roll-off at 40hz will take only half of the time of FR roll-off at 20hz), in almost every area. Just remember someone once said "the best bass is no bass" (I don't want to say who he is as he wasn't thinking clearly when he said it). Ilkka (the reference of our DIY subwoofer) had at one time usedcurve A, B, C, D.. as the label, completely do without numbers exactly for this reason.

Now, the curves from Databass for FV15HP has -3db at 18.7hz in 2 port mode. At 20hz, it has less than 1db roll-off. So first, that is a true deep extension subwoofer. Second any db label on the measurement has a better correlation with the output at 20hz whereas the so-called 110db curve for VTF-15H is more like 100db at 20hz for 2 port mode.

Now when it comes to servo, most people will think it is to reduce distortion simply because that concept is simple to understand. But it goes beyond that. One of the area that servo improves is the linear scalability. Databass site publishes curves from 90db all the way to 110db, it serves a purpose. It wants to see how a sub scales with different input level. So if we have a particular 90db FR curve, we want to see in ideal case that when input increases by 5db, the output will simply have 5db added to 90db FR curve. Same thing if the input increases by 10db, 15db, ..etc. Now the best way to check this linear scalability is we can just use 90db as reference, deduct (5db + 90db curve) from the 95db curve, and deduct (10db + 90db curve) from the 100db curve,...etc and all these plots form a so-called "output compression magnitude plot". If a system is perfectly linearly scalable, all these normalized curves will be on top of one another and be 0db. But in reality, the measurement will inevitably pick up noise in one or two measurements. That can cause it to have deviation on one or two curves. It is important to check the tend. Our FV15HP shows the best output compression curve that any sub can see (even better than Velodyne DD-18). The plot of 1 port mode shows the curves are in an extreme tight range above 30hz. The entire band of curves do move up and down because the noise in the 90db measurement curve has moves every other curves up and down at the same time.

So why is this important? Music is dynamic and constanly changing its signal strength. The ability to maintain linearity throughout the entire signal strength range is the first key to high fidelity. In non-servo, the problem is so serious that engineers just cross their fingers and hope for the best. On the other hand, servo completely solves this problem. Moreover, one reason nonservo subs have these problems is because the voice coil temperature can change after we put in that 100W to 600W power to the voice coil. When the temperature goes up, so is the voice coil resistance and that chokes the amount of current going to the driver even when the amplifier output stays the same. Unortunately voice coil temperature does not cool down instantaneously. That becomes a memory effect. We all see how a pressure on a memory foam will leave an imprint that takes time to recover. Same thing is heating up the voice coil. So why is this important? Same linear scalability needs to apply to time domain as well(vs in the domain of the signal strength as discussed above). If we measure a 90db curve A at time moment 0, we expect the same 90db curve to be repeatable at any other time. This seems to be very easy. But later we will see how much better our servo subs perform. The way to test this is Josh will publish two 90db curves in the "long term output compression" plot. The first 90db curve is what he normally runs. The second 90db curve (labelled as 90db REPEAT) is done as soon as he finishes the highest SPL sweep (after the voice coil heats up). Our sub is the only sub that has those two curves almost identical. It is not because of luck. It is because of servo operation. The problem of memory effect is that if we have notes A, B, C, and D. The sequence of these notes can change the strength of each because the power burnt by each note will affect the output of subsequent notes up to some time. It is a type of distortion. Our subs will sound more realistic because it is linear scalable on both signal and on time. The sequence of notes does not affect the playback strength of each note. You can play ABCD or DCBA and each A will have the same strength. That is the coherance we want.

As for the measurements from home theater shack, we need to add 6db to their numbers to be comparable to the number from Databass because they are measured at difference distance. If I am not mistaken, the former is at 2m whereas the latter is at 1m.

Last, I am not sure if anyone notice that FV15HP decay plots was done down to -35db from the reference and VTF-15H was done only down to -30db from the reference. In shor, the former was plotted with 5db higher resolution. It makes the direct comparison a bit more difficult.

Brian, thank you for taking the time to give me such a detailed and informative response. It's nice to know that you truly care about sound quality and not just sales. This goes a LONG way in my book.

I think for most of us that have never engineered a subwoofer before, looking at plots and graphs is an easy way for us to decide on which subwoofer we want to buy (especially if we had never heard it before). It's good to know that plots and graphs may not always be as black and white as they seem, as one like myself that will not be buying a subwoofer again for a very, very long time will want to make the right decision for their situation.

As for my case, I wouldn't be able to afford dual VTF-15Hs or Dual FV15HPs. So, it really comes down to the PB-2000, F12, or LV12r. Taking price out of the equation between your 2 models, which would be the best for my situation: going with duals, 13x18x8ft room, tight transient response, want to be able have clean dynamic range up to 103 db at 20hz, and play linear down to 20hz. I know that I may not be able to get all that I ask for at that price point, but I really value dynamic range and linearity. If it can be tight and transient as well, that is a major plus. Knowing the things I value, what you would go for in that price point?

Again, thanks for your detailed and very informative response.