Official Rythmik Audio Subwoofer thread - Page 1241 - AVS Forum | Home Theater Discussions And Reviews
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post #37201 of 39454 Old 02-26-2019, 04:28 PM
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Originally Posted by 3db View Post
My bad. The Velodyne was used in the other forum and I mixed the two up. I meant to post sensing coil.

So if the servo does limit frequency response, does it do it on both ends of the bass spectrum? I thought the sensing coil generated feedback based on the amplitude of the signal the driver is producing rather than its frequency. That's where I'm getting stuck. If what you say is true, then the LV12-R that I own is capable of 19Hz just from the driver/cabinet alone and that the servo reduces the amount of distortion of the output?

No need to get chirpy. I'm not criticizing you.
Sorry, general snarkiness on several fora seems high lately and I must have read more into your post than you meant. My hand-waving posts are not usually meant to be 100% rigorous, just trying to provide a little insight without assuming an engineering background (in which case you wouldn't be asking what feedback does).

It is hard to describe feedback theory and application without knowing the technical level of the audience. And even harder in words; I work better with a whiteboard. The following is hand-waving.

The servo can extend the useful linear range of the sub, which makes it possible to modify the intrinsic frequency response curve of the driver/box combination, which allows for a bit more bass extension. The limitation in frequency is at the upper limit; the lower limit is generally unaffected by feedback unless intentionally modified (e.g. analog tone controls were often designed as feedback circuits).

The frequency limitation of a servo, like any feedback circuit be it in your speaker, power amplifier, or car's engine controller, depends upon how much gain and bandwidth you have. See e.g. https://en.wikipedia.org/wiki/Loop_gain . In words, you sense the output, invert it, and apply it back to the input of the amplifier (or apply it to the inverting/negative input of the amplifier circuit with the signal going to the in-phase/positive input). This is feedback, not specific to a subwoofer. There is some delay through the amplifier and potentially through the feedback circuit itself. The amplifier only has so much gain and bandwidth; the greater the bandwidth, the lower the delay, and the greater the gain, the more it can be reduced by feedback to linearize (improve) the output.

The greatest bandwidth is for an open-loop amplifier with no feedback. But that is also the highest distortion way to do it. Most add some feedback, with the output signal used to compensate the nonlinearity of the amplifier (or speaker), and that trades some of the amplifier's gain and bandwidth for greater linearity (lower distortion) as well as helping other things (like lower output impedance). Look up Bode plots. A catch is that, since it takes a little time for the signal to get through the amplifier (plus sensor, accelerometer, voice coil, or just a resistor circuit from the output), at some point that delay shifts the phase enough so that the feedback ends up adding instead of subtracting and now the signal builds up uncontrollably and you've built an oscillator (the amp goes unstable and squeals). You have to design the feedback circuit with the amplifier so that by the time (frequency) the signal reaches that much delay it is below the unity-gain point of the amp. Then the signal is attenuated instead of amplified, and the amp remains stable.

So you end up trading some of the amp's intrinsic gain-bandwidth to provide a more linear outcome, in general reducing both gain and bandwidth compared to an amplifier without feedback. Same thing applies to subwoofers or steam engines with a servo circuit. But, to make a stable design, the bandwidth must be well above what you actually need, and thus it is with Rythmik subs (or other servo speaker designs). Adding a servo means you may need a little more bandwidth in the amp to achieve the same bandwidth as a non-servo design, but for a sub that is easily achieved. For Ka band radar amp up around 40 GHz, it's a little harder , and you rarely find the kind of gain-bandwidth you find in audio circuits.

That is why I used (albeit quite erroneous) light analogy; the bandwidth may be a little lower, but still so high it doesn't matter. If the light reaches my eyes when I throw the switch at only half the speed of light in a vacuum that is still quite fast enough to do the job without me noticing, and listening in a vacuum is uncomfortable and has numerous other drawbacks.

HTH - Don
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post #37202 of 39454 Old 02-26-2019, 05:12 PM
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Quote:
Originally Posted by chucky7 View Post
FV25HP and G25HP output comparison:

these differences look huge to me...but if not trying for 120db+ I doubt could tell difference.
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post #37203 of 39454 Old 02-26-2019, 05:37 PM
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Originally Posted by muscles View Post
Has anyone ever heard a G25HP and an FV25HP or compared the two? Any idea on what the output difference from say 10hz-100hz? They both have the same amps and drivers, the only difference is the port, correct? Would there be a noticeable sound quality difference? I know at 20hz the FV25HP has 5-6db advantage, does the G25hp ever exceed the FV25hp in the upper frequencies? Anyone in OC or LA have an FV25hp? I am assuming that the FV25hp has the amp on the back which would make it pretty hard to get to the settings to switch, if one were so inclined to do frequently.

Greg
I can tell you that my FV15HPs pair has more TR than your g25’s pair due to ported and suspended floor versus your concrete floor.
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post #37204 of 39454 Old 02-26-2019, 10:07 PM
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Originally Posted by torii View Post
in my large open room I can very easily adjust ring of my subs to nothing or fully bloated...maybe its a lot harder in closed rooms? if I eliminate most ringing it sure sounds clean but kinda thin. I need some ringing, maybe out to 300ms is about where I like my setup.
Thing thing about this discussion is that the decay time of a room is the same no matter what speaker you put in it - so we need to be clear what we're talking about here. You can increase room ringing by making the sub louder, and decrease it by turning the volume down. But the amount of time it takes the room to stop ringing is not, I believe, what you're interested in analyzing when trying to compare subwoofers.

There is very little use in comparing a waterfall of one sub vs another if the rooms are changed as well. You are then talking about the total decay of the system, because you are hearing and measuring the whole room; and you can't isolate the component from that.
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post #37205 of 39454 Old 02-27-2019, 05:47 AM
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Quote:
Originally Posted by chucky7 View Post
Would you like to comment on the meaningfulness of comparing waterfall graph of sub A in one room with that of sub B in another?
Let us go back to the original post.

"I was impressed at how crisp and clear the bass was for music with the F12s (it was a downgrade for HT of course). I think the difference I heard was due to faster decay times (see this waterfall for decay times on my current system with the JTRs https://i.imgur.com/6drYUOR.png).".

There are two things mentioned: A) how crisp and clear the bass was for music with the F12s and B) I think the difference I heard was due to faster decay times. Now, which of A) and B) he got first? Do you think he got B) first and then conclude he should get A)? Or he got A) first and then he is trying to correlate to B)? We all think he is the latter case. So whether B is exactly 100% correct is less important and Tvuoug already tried to steer you from there. From my perspective, reason B) is just one of the factors contributes to crisp and clear sound. Examples of other factors that we address with servo subwoofers that also contribute to crisp and clear bass are:

First, servo subs address memory effects of spider and surround material. The memory effect is one of the reasons bassline is blurred (or less rhythm, not rythmik enough). When you play a sequence of notes, how does the previous note change the "state of the driver" and how that affect the next note is called memory effect. The ideal transducer is zero memory effect. Today there is no test to reliably test memory effect. For electronics, there has been staircase waveform or other proposed methods. But none of that works for subwoofers because subwoofer distortion is so high that one cannot separate harmonic distortion from memory distortion. So how do I know the memory effect is reduced in our servo subwoofers? Because I have a mathematical model to calculate the factor.

Second, less boxy sound. Drivers produce sound on both sides of cone. Where does the energy from back of the cone go? If the back energy can bounce back and hit the cone and cause the cone to move even minutely, that back wave energy (we call re-radiation) will be mixed with the next note. Now the cone is being moved and energy is now on the cone and that energy can again produce a yet more minute back wave into the box. Servo addresses this problem. When the first back wave comes back to the cone, servo feedback detects the cone movement and exerts an opposite "damping force" to counteract the cone movement. So two things happen. The first is the cone movement is reduced by a factor of 3x. Second, the amplifier force produced by the servo feedback is a "damping" force so it dissipates more energy during this counteraction process. That leads to even faster decay of boxy sound.

Third, servo corrects the low frequency response without calibration. How many manufacturers assemble their subwoofers next to an anechoic room? If they do, how much would that subwoofer be? This is important because wavelength is longer at the low end and any anomaly will be audible "over time" and that is also where all the EQ and curve correction happens with non-servo subs. We all can send a unit to Josh to test. But what is the mechanism to ensure the production units are 95% or even 99% close to that unit? This is called product consistency. Servo has absolutely huge advantage over DSP EQ because the variability of T/S parameters are in the feedback loop. DSP EQ cannot possibly know the T/S parameters of the driver.

The above are just some reasons that go beyond what Josh has tested. But that does not mean we think Josh test is less important. What good does servo do if we cannot even perform better with Josh's tests. But again science is relative to knowledge. We know there are other factors affecting the sound quality. What kind of objective and repeatable tests we can come up? Unfortunately most of are infatuated with DSP and think DSP can address everything. DSP is just as smart as we are. If we don't have the model for the problem that we want to address, DSP is not gonna solve it for us.

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post #37206 of 39454 Old 02-27-2019, 06:38 AM
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Decay time in general

I have been into a few local car dealer medium rooms. I left the room after less than a minute. For me the sound is dead because too much deafening material is put in there. it is almost like in anechoic room. If you go to a concert hall, it is the opposite of that. We hear open sound. Controlled reverberation is the key. Our HiFi systems projects sound stage because of wall reflection. So we do need them to feel the music is not dry. But at the same time, decay time of the speaker is not the same as the decay time from the wall reverberations.
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post #37207 of 39454 Old 02-27-2019, 06:49 AM
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^^^^^^
What he said.
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post #37208 of 39454 Old 02-27-2019, 07:33 AM
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Quote:
Originally Posted by Rythmik View Post
Let us go back to the original post.

"I was impressed at how crisp and clear the bass was for music with the F12s (it was a downgrade for HT of course). I think the difference I heard was due to faster decay times (see this waterfall for decay times on my current system with the JTRs https://i.imgur.com/6drYUOR.png).".

There are two things mentioned: A) how crisp and clear the bass was for music with the F12s and B) I think the difference I heard was due to faster decay times. Now, which of A) and B) he got first? Do you think he got B) first and then conclude he should get A)? Or he got A) first and then he is trying to correlate to B)? We all think he is the latter case. So whether B is exactly 100% correct is less important and Tvuoug already tried to steer you from there. From my perspective, reason B) is just one of the factors contributes to crisp and clear sound. Examples of other factors that we address with servo subwoofers that also contribute to crisp and clear bass are:

First, servo subs address memory effects of spider and surround material. The memory effect is one of the reasons bassline is blurred (or less rhythm, not rythmik enough). When you play a sequence of notes, how does the previous note change the "state of the driver" and how that affect the next note is called memory effect. The ideal transducer is zero memory effect. Today there is no test to reliably test memory effect. For electronics, there has been staircase waveform or other proposed methods. But none of that works for subwoofers because subwoofer distortion is so high that one cannot separate harmonic distortion from memory distortion. So how do I know the memory effect is reduced in our servo subwoofers? Because I have a mathematical model to calculate the factor.

Second, less boxy sound. Drivers produce sound on both sides of cone. Where does the energy from back of the cone go? If the back energy can bounce back and hit the cone and cause the cone to move even minutely, that back wave energy (we call re-radiation) will be mixed with the next note. Now the cone is being moved and energy is now on the cone and that energy can again produce a yet more minute back wave into the box. Servo addresses this problem. When the first back wave comes back to the cone, servo feedback detects the cone movement and exerts an opposite "damping force" to counteract the cone movement. So two things happen. The first is the cone movement is reduced by a factor of 3x. Second, the amplifier force produced by the servo feedback is a "damping" force so it dissipates more energy during this counteraction process. That leads to even faster decay of boxy sound.

Third, servo corrects the low frequency response without calibration. How many manufacturers assemble their subwoofers next to an anechoic room? If they do, how much would that subwoofer be? This is important because wavelength is longer at the low end and any anomaly will be audible "over time" and that is also where all the EQ and curve correction happens with non-servo subs. We all can send a unit to Josh to test. But what is the mechanism to ensure the production units are 95% or even 99% close to that unit? This is called product consistency. Servo has absolutely huge advantage over DSP EQ because the variability of T/S parameters are in the feedback loop. DSP EQ cannot possibly know the T/S parameters of the driver.

The above are just some reasons that go beyond what Josh has tested. But that does not mean we think Josh test is less important. What good does servo do if we cannot even perform better with Josh's tests. But again science is relative to knowledge. We know there are other factors affecting the sound quality. What kind of objective and repeatable tests we can come up? Unfortunately most of are infatuated with DSP and think DSP can address everything. DSP is just as smart as we are. If we don't have the model for the problem that we want to address, DSP is not gonna solve it for us.
This is a very informative post for me.
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post #37209 of 39454 Old 02-27-2019, 09:27 AM
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I feel like I got smacked around with a little knowledge there!

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post #37210 of 39454 Old 02-27-2019, 09:37 AM
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Taken to school for sure! Excellent post Brian
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post #37211 of 39454 Old 02-27-2019, 12:35 PM
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Quote:
Originally Posted by torii View Post
these differences look huge to me...but if not trying for 120db+ I doubt could tell difference.
Full disclosure, part of me was going to upgrade just for the aesthetic aspect. I like to see both drivers and i like a taller, shallower depth subwoofer. I have spoken to many people who have said that the G25HP is one of the best sounding subwoofers out there, and it gets plenty loud and has a ton of TR in movies. It was more of a lateral move for looks, but it sounds like I would miss the sound quality of the G25HP, because I do like the best sound quality and have built my system around it.

Greg

Subwoofers: Dual Rythmik F18SEs - SB13 Ultra
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post #37212 of 39454 Old 02-27-2019, 02:19 PM
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Quote:
Originally Posted by muscles View Post
Full disclosure, part of me was going to upgrade just for the aesthetic aspect. I like to see both drivers and i like a taller, shallower depth subwoofer. I have spoken to many people who have said that the G25HP is one of the best sounding subwoofers out there, and it gets plenty loud and has a ton of TR in movies. It was more of a lateral move for looks, but it sounds like I would miss the sound quality of the G25HP, because I do like the best sound quality and have built my system around it.

Greg

I still have an old velodyne sealed hgs 12 sub. it only goes to 110db but its servo and sounds very good. what made me take note is that rythmik fv15hp and fv25hp sound better than my velodyne and are ported. I need ported in my open floorplan.
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post #37213 of 39454 Old 02-27-2019, 02:34 PM
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Quote:
Originally Posted by muscles View Post
Full disclosure, part of me was going to upgrade just for the aesthetic aspect. I like to see both drivers and i like a taller, shallower depth subwoofer. I have spoken to many people who have said that the G25HP is one of the best sounding subwoofers out there, and it gets plenty loud and has a ton of TR in movies. It was more of a lateral move for looks, but it sounds like I would miss the sound quality of the G25HP, because I do like the best sound quality and have built my system around it.

Greg
You did the right thing my friend. The G25HP is just the ultimate sealed subwoofer for audiophiles. I haven't heard anything like that in a very long time.
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post #37214 of 39454 Old 02-27-2019, 03:28 PM
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I saw on the website that the rev 2 FV18 paper cones subs are on back order until the end of February. Any idea when the will be available to order? Thanks

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post #37215 of 39454 Old 02-27-2019, 03:38 PM
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This is taking too many posts than I would like in this thread. I have made my point loud and clear and I am glad some get it. That is good enough for me. This is my final post regarding this exchange.

Quote:
Originally Posted by Rythmik View Post
Let us go back to the original post.

"I was impressed at how crisp and clear the bass was for music with the F12s (it was a downgrade for HT of course). I think the difference I heard was due to faster decay times (see this waterfall for decay times on my current system with the JTRs https://i.imgur.com/6drYUOR.png).".
That is not the whole "original post". You have conveniently left out the part underlined in red, which is I was getting at:



It is clear that pink soda heard a difference in sound (I never debated this), and thinks the difference is because the decay time of the JTRs in his HT (https://i.imgur.com/6drYUOR.png) is longer than the F12s in the friends's HT (under 120 ms at 25 hz and above). What he did is very common for REW users. We heard a difference and we look for answers from the FR measurements.

Notice that in the exchanges above, I have not posted anything in the line of: "PS, you are wrong because XXX is better than YYY!!!" This is not about fanboism.

I posted the waterfall graphs of the products mentioned, which all were tested to have more than 120ms outdoors. Put these subs in any normal untreated room, the decay time will only increase. The reason CEA-2010 works is it set forth a guideline for measurements done in outdoor setting with temperate (60~80 F) and moisture range, therefore the results from different test sessions are apples to apples. This is not the case here. Period.

Quote:
Originally Posted by Rythmik View Post
There are two things mentioned...
TL; DR...

Would you please stop defending your patented Direct Servo technology because it was never under attack in the first place?

The fact is, there are much more subwoofer companies not using Servo. There are at least 3 other ID company's products that are known for very very good SQ. I have heard two of them.

Speakers: L/C/R: JTR Neosis 212HT. Surrounds: Jamo C103, KEF Q100, Polk Audio RTiA3.
Subwoofer: JTR Captivator 4000ULF.
AVR: Denon AVR-X4400H. TV: Samsung UN75NU8000FXZA.

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post #37216 of 39454 Old 02-27-2019, 04:11 PM
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Quote:
Originally Posted by muscles View Post
Full disclosure, part of me was going to upgrade just for the aesthetic aspect. I like to see both drivers and i like a taller, shallower depth subwoofer. I have spoken to many people who have said that the G25HP is one of the best sounding subwoofers out there, and it gets plenty loud and has a ton of TR in movies. It was more of a lateral move for looks, but it sounds like I would miss the sound quality of the G25HP, because I do like the best sound quality and have built my system around it.

Greg

I still have an old velodyne sealed hgs 12 sub. it only goes to 110db but its servo and sounds very good. what made me take note is that rythmik fv15hp and fv25hp sound better than my velodyne and are ported. I need ported in my open floorplan.
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post #37217 of 39454 Old 02-27-2019, 04:16 PM
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chucky7,

I think you missed a couple of things.

1. Brian explained the servo tech probably in response to 3db's inquiry, but it broadly applies
2. Brian explained (as did others) that the decay of the room and the sub are not to be confused. His last words were literally:

Quote:
Originally Posted by Rythmik View Post
But at the same time, decay time of the speaker is not the same as the decay time from the wall reverberations.
Therefore, you are having a heated agreement.
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post #37218 of 39454 Old 02-27-2019, 04:41 PM
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Quote:
Originally Posted by chucky7 View Post
Would you please stop defending your patented Direct Servo technology because it was never under attack in the first place?

The fact is, there are much more subwoofer companies not using Servo. There are at least 3 other ID company's products that are known for very very good SQ. I have heard two of them.
Chucky, Brian does not defend his servo technology. He does not need to. Most people including myself found what he posted about servo technology is very clear and informative for consumers. It is free education as it does make lots of sense and I appreciate what he wrote.
There are companies out there that can achieve good to great SQ quality without servo, no one argues with that. Servo is one way to achieve that great SQ, not the ONLY way. In the context of the OP, I do believe Rythmik servo is what makes them having better SQ than JTR.
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post #37219 of 39454 Old 02-27-2019, 04:43 PM
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Originally Posted by muscles View Post
Full disclosure, part of me was going to upgrade just for the aesthetic aspect. I like to see both drivers and i like a taller, shallower depth subwoofer. I have spoken to many people who have said that the G25HP is one of the best sounding subwoofers out there, and it gets plenty loud and has a ton of TR in movies. It was more of a lateral move for looks, but it sounds like I would miss the sound quality of the G25HP, because I do like the best sound quality and have built my system around it.

Greg
Greg,

Your system is music first - sealed.
The kind of music you listen to - ported.
Your room looks to be open - ported.
What you already have - sealed.

If you were starting from scratch, I would definitely recommend ported because of output per dollar at ULF. But you are not... Personally, I feel the FV18 I heard already sounded like sealed so I don't think you will be giving up much SQ if you go with ported.
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post #37220 of 39454 Old 02-27-2019, 05:12 PM
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Originally Posted by Rythmik View Post
Let us go back to the original post.

"I was impressed at how crisp and clear the bass was for music with the F12s (it was a downgrade for HT of course). I think the difference I heard was due to faster decay times (see this waterfall for decay times on my current system with the JTRs https://i.imgur.com/6drYUOR.png).".

There are two things mentioned: A) how crisp and clear the bass was for music with the F12s and B) I think the difference I heard was due to faster decay times. Now, which of A) and B) he got first? Do you think he got B) first and then conclude he should get A)? Or he got A) first and then he is trying to correlate to B)? We all think he is the latter case. So whether B is exactly 100% correct is less important and Tvuoug already tried to steer you from there. From my perspective, reason B) is just one of the factors contributes to crisp and clear sound. Examples of other factors that we address with servo subwoofers that also contribute to crisp and clear bass are:

First, servo subs address memory effects of spider and surround material. The memory effect is one of the reasons bassline is blurred (or less rhythm, not rythmik enough). When you play a sequence of notes, how does the previous note change the "state of the driver" and how that affect the next note is called memory effect. The ideal transducer is zero memory effect. Today there is no test to reliably test memory effect. For electronics, there has been staircase waveform or other proposed methods. But none of that works for subwoofers because subwoofer distortion is so high that one cannot separate harmonic distortion from memory distortion. So how do I know the memory effect is reduced in our servo subwoofers? Because I have a mathematical model to calculate the factor.

Second, less boxy sound. Drivers produce sound on both sides of cone. Where does the energy from back of the cone go? If the back energy can bounce back and hit the cone and cause the cone to move even minutely, that back wave energy (we call re-radiation) will be mixed with the next note. Now the cone is being moved and energy is now on the cone and that energy can again produce a yet more minute back wave into the box. Servo addresses this problem. When the first back wave comes back to the cone, servo feedback detects the cone movement and exerts an opposite "damping force" to counteract the cone movement. So two things happen. The first is the cone movement is reduced by a factor of 3x. Second, the amplifier force produced by the servo feedback is a "damping" force so it dissipates more energy during this counteraction process. That leads to even faster decay of boxy sound.

Third, servo corrects the low frequency response without calibration. How many manufacturers assemble their subwoofers next to an anechoic room? If they do, how much would that subwoofer be? This is important because wavelength is longer at the low end and any anomaly will be audible "over time" and that is also where all the EQ and curve correction happens with non-servo subs. We all can send a unit to Josh to test. But what is the mechanism to ensure the production units are 95% or even 99% close to that unit? This is called product consistency. Servo has absolutely huge advantage over DSP EQ because the variability of T/S parameters are in the feedback loop. DSP EQ cannot possibly know the T/S parameters of the driver.

The above are just some reasons that go beyond what Josh has tested. But that does not mean we think Josh test is less important. What good does servo do if we cannot even perform better with Josh's tests. But again science is relative to knowledge. We know there are other factors affecting the sound quality. What kind of objective and repeatable tests we can come up? Unfortunately most of are infatuated with DSP and think DSP can address everything. DSP is just as smart as we are. If we don't have the model for the problem that we want to address, DSP is not gonna solve it for us.
As an EE student taking classes in feedback control/design this was a very beautiful post to read.

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post #37221 of 39454 Old 02-27-2019, 06:44 PM
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One day I hope to have the room, but for now I just like the name...G25HP (branding important)

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post #37222 of 39454 Old 02-27-2019, 06:55 PM
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Official Rythmik Audio Subwoofer thread

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Originally Posted by chucky7 View Post

The fact is, there are much more subwoofer companies not using Servo. There are at least 3 other ID company's products that are known for very very good SQ. I have heard two of them.

Yeah and rythmik sits atop all of them.

After hearing 5-6 different brands in my room, the best SQ was Rythmik and Seaton. There is truth to servo contributing to better SQ whether you like it or not my friend.




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Subwoofers: Dual Rythmik FV18s Rev2 with Paper cone, BOSS Platform mini riser
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post #37223 of 39454 Old 02-28-2019, 02:05 AM
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rythmik subs sound good and perform well. my younger snobbier days I would never have bought an id company. I would be all over rel/jl audio with external apps and remotes...shoot my 20yr old velodyne has a dang remote...bought a 15hp just out of curiosity and was super impressed. still wish they had a remote. but they perform so well I dont miss all the fancier bells and whistles. makes you focus on setup/dialing in.

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post #37224 of 39454 Old 02-28-2019, 02:24 PM
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Quote:
Originally Posted by Rythmik View Post
Let us go back to the original post.

"I was impressed at how crisp and clear the bass was for music with the F12s (it was a downgrade for HT of course). I think the difference I heard was due to faster decay times (see this waterfall for decay times on my current system with the JTRs https://i.imgur.com/6drYUOR.png).".

There are two things mentioned: A) how crisp and clear the bass was for music with the F12s and B) I think the difference I heard was due to faster decay times. Now, which of A) and B) he got first? Do you think he got B) first and then conclude he should get A)? Or he got A) first and then he is trying to correlate to B)? We all think he is the latter case. So whether B is exactly 100% correct is less important and Tvuoug already tried to steer you from there. From my perspective, reason B) is just one of the factors contributes to crisp and clear sound.

Spot on. I was familiar with the sound of that HT with the JTR 1400, as it was pretty similar to my JTR 118HT system. Then I heard that HT with the F12s, and after hearing the difference, I was interested in learning what caused those differences, and how to explain those differences with measurements (I see that now that the answer is complicated and I can't necessarily focus on one type of measurement, such as waterfalls). Because ultimately, I like what I heard, and I want to see what it would take to get that sound in my setup as well. I think a lot of folks on AVS operate this way.

Thank you Brian and everyone else for all the info. Dual FV18s look tempting. I see there are a few different options. I am leaning towards the aluminum cone for less distortion, would that be better for 50% HT/music? Also, what difference does the 3.5 inch vs 4 inch port make?
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post #37225 of 39454 Old 02-28-2019, 02:48 PM
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Originally Posted by pink soda View Post
Spot on. I was familiar with the sound of that HT with the JTR 1400, as it was pretty similar to my JTR 118HT system. Then I heard that HT with the F12s, and after hearing the difference, I was interested in learning what caused those differences, and how to explain those differences with measurements (I see that now that the answer is complicated and I can't necessarily focus on one type of measurement, such as waterfalls). Because ultimately, I like what I heard, and I want to see what it would take to get that sound in my setup as well. I think a lot of folks on AVS operate this way.

Thank you Brian and everyone else for all the info. Dual FV18s look tempting. I see there are a few different options. I am leaning towards the aluminum cone for less distortion, would that be better for 50% HT/music? Also, what difference does the 3.5 inch vs 4 inch port make?
For 50/50 Music/HT, I would go with FV18 aluminum cone. I had the chance to listen to the FV18 paper cone and JTR 118HT in Ray's room and they sounded very similar. It was hard for us to pick a winner. However, the FV18 paper cone was cleaner and more accurate with very difficult scenes. In terms of Tactile Response, they are very close. The FV18 aluminum cone sound is more like a sealed subwoofer with the output of a ported subwoofer. It has the right amount of accuracy, articulation and tactile response. Regarding the port caps, the new port caps (4") reduce air velocity which decrease the chance of having port noise below port tune (12Hz).
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Media Room: Sierra Towers w/RAAL, Horizon w/RAAL, Sierra 2s & Lunas | Rythmik F12SE(x2) + FV25HP | Denon X6500H | Panny 820 + ATV 4K | Bluesound Node 2 | 92" Stewart ST100 | Sony VW295ES |
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post #37226 of 39454 Old 03-01-2019, 04:30 AM
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I’ve got a question? First time doing this! I recently bought a FV25HP. I tried corner loading it and it sounded and felt so much better behind the couch. The couch is in the middle of the room. Is this weird? I’ve always had my best luck in a corner. But not this time. The FV25HP IS A BEAST.
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post #37227 of 39454 Old 03-01-2019, 04:53 AM
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Quote:
Originally Posted by Darrell Ommart View Post
I’ve got a question? First time doing this! I recently bought a FV25HP. I tried corner loading it and it sounded and felt so much better behind the couch. The couch is in the middle of the room. Is this weird? I’ve always had my best luck in a corner. But not this time. The FV25HP IS A BEAST.


Each sub interacts with room differently. So not a surprise. Place it where it measures and sounds best. Even moving a few inches here or there can make a difference. Do you have REW? That can help I see what you are hearing.


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Subwoofers: Dual Rythmik FV18s Rev2 with Paper cone, BOSS Platform mini riser
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Video: Epson PowerLite Home Cinema 6500 UB; Room: 2100 cuft sealed on suspended floor
Receiver & Players: Denon X4400H, Oppo UDP-203, Roku Ultra. Apple TV, Minidsp 2X4 HD
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post #37228 of 39454 Old 03-01-2019, 08:12 AM
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Quote:
Originally Posted by Darrell Ommart View Post
I’ve got a question? First time doing this! I recently bought a FV25HP. I tried corner loading it and it sounded and felt so much better behind the couch. The couch is in the middle of the room. Is this weird? I’ve always had my best luck in a corner. But not this time. The FV25HP IS A BEAST.
What can I say Darrell ... Some of us are weird

Not exactly in the middle of the room but depth of my HT is only 10 1/2 feet. When I first pulled out my seating it did seem strange but I'm used to it now. I'm about 6 1/2 feet from my Samsung and the LRC speakers. If I put my arms out to the sides my side surrounds are about 3" away from my finger tips
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Regards, Ken (Retired)
9.1.) Denon 4520CI; Samsung 55H8000; OPPO 203; 6x SVS Ultra BS,
Ultra Center; FH 2xPolk; Rythmik F12; CyberPower CP1500PFCLCD (x2)
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ADS L1290(x2); PINNACLE BABYBOOMER SUB, PANAMAX MR4300

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post #37229 of 39454 Old 03-01-2019, 08:22 AM
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Quote:
Originally Posted by Darrell Ommart View Post
I’ve got a question? First time doing this! I recently bought a FV25HP. I tried corner loading it and it sounded and felt so much better behind the couch. The couch is in the middle of the room. Is this weird? I’ve always had my best luck in a corner. But not this time. The FV25HP IS A BEAST.
Just do a subwoofer crawl to find the best spot for the subwoofer in the room. If it's behind the couch and you have no problems placing it back there, then go for it. I have my pair of F12SEs placed one on each side of the couch and the FV25HP in the back left corner of the room. I have no other places to put them and luckily enough, they sound great.
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Media Room: Sierra Towers w/RAAL, Horizon w/RAAL, Sierra 2s & Lunas | Rythmik F12SE(x2) + FV25HP | Denon X6500H | Panny 820 + ATV 4K | Bluesound Node 2 | 92" Stewart ST100 | Sony VW295ES |
Desktop: Dynaudio BM5 mkIII | Rythmik L22 | Apogee Quartet | 27" iMac| Bedroom: B&W 685 S2 | Rythmik LVX12 | Marantz SR6013 | Sony X700 + ATV 4K | Sony XBR-65Z9D |
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post #37230 of 39454 Old 03-01-2019, 09:01 AM
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Quote:
Originally Posted by Darrell Ommart View Post
I’ve got a question? First time doing this! I recently bought a FV25HP. I tried corner loading it and it sounded and felt so much better behind the couch. The couch is in the middle of the room. Is this weird? I’ve always had my best luck in a corner. But not this time. The FV25HP IS A BEAST.
What you experience is the TR feeling near field behind you versus further away in the corner. Having sub closer to you reduces the room interaction with your MLP. Corner placement can make sub sound boomier. Place it where it sounds best to you.
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