What To Do?

[speakerman39]

My ULS-15 MK2 just arrived. Good Lord the box is HUGE! Time, to get busy. Thanks to EVERYONE that has offered me their time and their advice. It is most appreciated.

Cheers,

Phil

 

[shadyJ]

I've since played that piece quite a bit louder than what I had recorded on that you tube video and I still didn't hear anything bad coming out of the sub. It did scare me a little doing it because I don't want to damage the sub. I didn't hear any thumps or anything indicating that driver hit its hard limits. The feedback mechanism is to prevent losing control of the driver but I suppose, it can compensate for stupidity.

You aren't likely to damage the sub with a complex signal like that, however, you can't really get any useful data from a complex signal either. You would want to use a test tone to see analyze the subs performance, but test tones run loudly can damage the sub if run recklessly. In fact, Rythmik considers it abuse that voids the warranty after a point: "Abuse includes continuously playing sine wave and other test tones for an extended period. A duty cycle greater than 25% is considered abuse, where the test tone plays for 15 seconds followed by a break of 45 seconds." - from Rythmik's site. If you are interested in seeing the driver's useful excursion, you need to set up a camera aimed at the driver in fixed position ( on a tripod, ideally) with a long exposure time. Put a piece of white tape on the dustcap. Take a picture of the driver at rest while holding a ruler on the tape. Play a deep frequency tone, like 16 Hz maybe, and push the driver until its starts distorting, than take a picture that captures the full swing of the driver. You can then easily compare the before and after pics by superimposing them to see how much throw the driver has until funny noises crop up. However, it would be better to use a laptop with a calibration mic and some RTA software to see where the driver is losing it. There are some free RTAs out there that would work well like TrueRTA or the RTA in REW.

 

[shadyJ]

Since it seems to be a continuing topic here, I'll chime in with a few cents. There are a couple good sets of measurements of Rythmik subs to look at, the FV15HP by Josh and a sealed DIY 12"er by Ilkka.

http://www.data-bass.com/data?page=system&id=51&mset=50
http://www.hometheatershack.com/forums/subwoofer-tests-archived/5756-diy-rythmik-audio-direct-servo-12-sealed-56l.html

Now there are obviously limits as to what the servo can do. You can see from Ilkka's data set on the that distortion can only be controlled to a point. However, one area where both measurements agree is with respect to compression. If you look at Josh's chart titled "Long Term Output Compression (Magnitude)", you'll see just how neatly its controlled by the servo mechanism. Obviously port compression is still an issue, but that's clearly beyond the scope of what the servo can deal with. The story is similar in Ilkka's testing. Aside from where the driver is displacement limited, output increases at a predictable rate.

Not trying to sound argumentative, but a small problem with compensating for compression is that it could hide or even exacerbate thermal compression until it's too late, however if you are running your sub so hard that thermal compression becomes a threat, you are really trying to beat the sub to death anyway. Nonetheless, I think I would prefer compression be addressed by the driver alone without help from external processing. There are a lot of subs which have very good compression behavior without help from signal processing.

 

[speakerman39]

UPDATE:

Folks, the ULS-15 MK2 is friggin huge....LOL!!!! Ran Audyssey and it originally set my RTi6's and CSi5 to Large. All of the levels were in the minus range. In fact, the sub was set -12db. I did, however, go back into the settings and set all my speakers to small with an 80 Hz crossover. Then, I set the sub crossover at 90 Hz. Leaving the levels as they are for the time being.

Next Wednesday my RTi8's will be here. So, got to do this all over again. My rear stage is NOT set-up just yet. The Rti6's will be doing rear duty whereas the RTi4's will be either my front Height or Width speakers. Plan to experiment with that some to see which I prefer. So far, Pandora sounds pretty good. Can't even begin to imagine what the ULS-15 MK2 would do if I increased the level from -12db!

My Rti6's sure sound very good. That is, they are beginning to open up more. The Polk RTi series of speakers are very good for HT and decent for music listening. Really don't think I would have needed the RTi8's, but it is much too late as they are on their way to me as we speak. So far so good. Dr. Hsu is a genius!

Cheers,

Phil

 

[shadyJ]

The ULS aren't that big. After all, I use a pair on my PC desktop!

 

[speakerman39]

The ULS aren't that big. After all, I use a pair on my PC desktop!

Well, to me I think it is pretty BIG. Things are not fully dialed in just yet. But, so far I am very impressed. I have the volume setting a little over half and it really blends well. Kept the level Audyssey set at -12db. Pearl Jam sounds really good on Pandora! Love It!

Cheers,

Phil

 

[PENG]

Well, to me I think it is pretty BIG. Things are not fully dialed in just yet. But, so far I am very impressed. I have the volume setting a little over half and it really blends well. Kept the level Audyssey set at -12db. Pearl Jam sounds really good on Pandora! Love It!

Cheers,

Phil

When you get the RTi8, before you run Audyssey again, turn the sub volume down to around 10 or 11 so the trim will be back down to around 0 or a little higher but hopefully still higher than -12, say -8 wouldn't be too bad.

 

[speakerman39]

When you get the RTi8, before you run Audyssey again, turn the sub volume down to around 10 or 11 so the trim will be back down to around 0 or a little higher but hopefully still higher than -12, say -8 wouldn't be too bad.

Yeah, just read it is a good idea to turn the trim up until I can read 75 db on my SPL meter. Then, run Audyssey. Supposed to get much more accurate and better results. I am not to worried right now about that until my RTi8's get here. Plus, I will also have to put my RTi6's in the rear on walls. Thus, the RTi4's are going to be mounted for Height or Width. Plan to experiment with that to see whichever I prefer. Right now, however, the RTi6's are really sounding very good. The ULS-15 MK2 is incredible to say the least. Thanks for the tip Peng!

Cheers,

Phil

 

[3db]

Not trying to sound argumentative, but a small problem with compensating for compression is that it could hide or even exacerbate thermal compression until it's too late, however if you are running your sub so hard that thermal compression becomes a threat, you are really trying to beat the sub to death anyway. Nonetheless, I think I would prefer compression be addressed by the driver alone without help from external processing. There are a lot of subs which have very good compression behavior without help from signal processing.

Whatever your preference Shady, the servo feedback works and works very well. I'm extremely happy with my subs performance and in its price class is very hard to beat.

 

[3db]

What I was really referring to was a comparison of "with" vs "without" servo so we can see what, exactly, the servo adds!
That may be impossible.

I think this measurement you would like to see would be relevant if the servo mechanism could be disabled by a switch.. However, since Rythmik chose a low mass driver to work in conjunction with the servo, using it without the servo would likely cause a poor response.

From Jman's review of the LV-12R...

According to Rythmik the process for correcting the signal occurs in the following manner:

1. The plate amplifier receives a signal which is filtered on the pre-amp board to achieve correct integration. The signal from the preamp passes to the power amplifier which then sends the amplified signal to the voice coil of the driver. The amplified signal is shown above in red.
   
2. As the amplified signal passes through the voice coil, the cone moves and begins to reproduce the signal.
   
3. At the same time as the cone is moving in response to the amplified signal, the sensing coil is generating a feedback signal. There is no time delay between step 2 and 3 because they occur simultaneously. While the cone is moving, the sensing coil is sending feedback. The sensing coil is a specialized microphone which measures the precise output of the driver. The correction signal is shown above in blue.
   
4. The correction signal is fed back into the summing points of the amplifier. It is compared to the original signal and corrections are made without the use of any active circuits.
   
5. The driver reproduces a signal that has been corrected by instantaneous feedback. Detrimental memory effects have been eliminated and the sound is true to the original.

Some of the benefits Rythmik claims Direct Servo provides are:

• 
  
  
  • Reduction of the effects of thermal compression are eliminated under normal operation
  • Higher efficiency allowing output which would normally require a more powerful amplifier
  • Deep bass extension can be achieved using a low mass driver with superior transient response
  • Mechanical and thermal memory effects are reduced, further improving transient response
  • Much greater damping control over the cone
  • Dramatic reduction of the re-radiation of bass from inside the box

Even with my sub configured with max extension, this sub is very musical and sounds great with all the music I throw at it including jazz.

 

[speakerman39]

Here is a pic of my set-up:

Still learning how to put pics on websites. As YOU can also see I am no photographer. Much more work to do.

Cheers,

Phil

 

[speakerman39]

Here is another pic:

 

[speakerman39]

Sorry guys I am still learning here:

 

[speakerman39]

Here is another for you guys:

 

[speakerman39]

Guys, I am not too concerned about hiding wires just yet. Waiting on my RTi8's to get here then I will work on it some. Figured that I will have to move things around some. So, once all that is out of the way, then I will focus a lot more on hiding cables, speaker wire, and etc. Will post a few more pics. BTW, the tables/stands I am using for my RTi6's actually belonged to my Sister. She passed away 6-years ago. So, have been holding on to them. I think they actually look pretty good, no?

Cheers,

Phil

 

[speakerman39]

Another pic:

 

[KEW]

LOL, so I gather you binge eat candy bars while watching.
The endorphines released from chocolate are likely to make your system sound better!

Lookin' good, but can't wait to see the towers in place!

 

[speakerman39]

LOL, so I gather you binge eat candy bars while watching.
The endorphines released from chocolate are likely to make your system sound better!

Lookin' good, but can't wait to see the towers in place!

Actually Kurt, I sell candy bars....LOL. Got to make a buck here and there. But, have been known to sample a few every once in a while. Right now, just trying to get up and running. Once the towers are here and I get things moved around to where they need to be, then I will work on the wire mess as best as I can. Might have to order some new cables, and etc. for proper lengths/better fit. The ULS-15 Mk2 rocks!

Cheers,

Phil

 

[speakerman39]

Yet another:

 

[speakerman39]

One more: