Wishing a warm welcome to Rythmik Audio

[curtis]

Anyone,
can you explain to me how the damping factor and rumble filter work exactly.
I believe the rumble filter is just another term for high pass filter, correct? But I'm not sure how those settings relate to damping.

I think the Rythmik site has some good information.

The differences in damping settings were pretty noticeable to me. I use high damping and 14hz. Play around with the settings to see what you like best. There is no right or wrong here.

[RythmikAudio]

I think the Rythmik site has some good information.

The differences in damping settings were pretty noticeable to me. I use high damping and 14hz. Play around with the settings to see what you like best. There is no right or wrong here.

Curtis is correct. We have both rumble filter and extension filter. But we shouldn't confuse the two. First, extension "filter". Even though we call it "filter", it is not any loss of signal when compared to conventional sealed subwoofers. Servo subwoofers, when used without extension filter, can extend down to 5hz. But that has little practical use. So we put in a 2nd order HP filter to match a normal sealed subwoofers. Since I have to put one in anyway, I also notice all sealed subs they have slightly different corner frequency and different damping characteristic, wouldn't it better to put in one offering some versatility? So I come up with 3 frequency and 3 damping setting for a combination of 9. In practice I found them to be very useful too. My favorite is high damping (in all music, movies, and games). It gives the least ringing of the 3 damping settings (and in theory it should have no ringing at all). It also gives an edge in terms of clarity because of lack of ringing. You will notice that in all music contents, even in synthesized music such as game. As more and more customers get their hands on the servo subwoofers, they can compare notes. The low damping has the largest ringing, but it has steeper roll-off. This type of roll-off contouring combined with higher corner frequency has been used by early minimonitors such as L/S 3/5A. The advantage is that it is able to play louder (only when you set it at 28hz) as compared to 14hz high damping.

Rumble filter is different. It is a third order extra filter for those still use Vinyl, or those movies with too much subsonic content and therefore overloads the amplifier. It has only on and off position. The roll-off frequency is 20hz.

[jedi.night]

I think the Rythmik site has some good information.

The differences in damping settings were pretty noticeable to me. I use high damping and 14hz. Play around with the settings to see what you like best. There is no right or wrong here.

Thanks curtis,
Is your setup primarily for Movies or Music?

[curtis]

Thanks curtis,
Is your setup primarily for Movies or Music?

Both!

[RythmikAudio]

I am booked for a trip for whole next week. There will be no subwoofers shipped from us or Ascend. Please patiently wait for me come back to work on Nov 24.

[RythmikAudio]

I am booked for a trip for whole next week. There will be no subwoofers shipped from us or Ascend. Please patiently wait for me come back to work on Nov 24.

I have uploaded a page explaining phase alignment and its importance. http://www.rythmikaudio.com/phase1.html

The short version of it is that if one uses an HT receiver and its bass management for subwoofer and set the vented front spekaers to small, one needs to put the distance of subwoofer 4 ft farther than what it actually is (compared to the front speakers) so that it fools the receiver to put in a phase lead to the subwoofer to compensate for the extra of vented front speakers as compared to sealed front speakers. 4 ft is for 5" woofer in the front speakers. For 7" woofer in vented front speakers, I would recommend 2 ft as a ball part number to start with. For sealed front speakers, one can try just 1 or 2 ft farther to see if it improves the integraton (by filling up the mid bass sound).

[Jonnyozero3]

Interesting...do you think that any of the Auto setup routines like MCACC, Audyssey, EZset/EQ, YPAO, etc compensate for this? My AVR (HK AVR435) has always set my sub at a far greater distance than it is (chooses like 10ft when the sub is ~3ft away).

[scape]

Interesting...do you think that any of the Auto setup routines like MCACC, Audyssey, EZset/EQ, YPAO, etc compensate for this? My AVR (HK AVR435) has always set my sub at a far greater distance than it is (chooses like 10ft when the sub is ~3ft away).

my denon put it mine at 16ft, when it's at 10ft from listener. after reading brian's comment, that makes sense now. however, I'm not sure how far these calibrations actually go, where as professional setup might still enhance things.

[RythmikAudio]

Well I don't know how robust the EQ algorithm is. I deal with software that affects millions of dollars of design works every day. In that case, there is always a verification step that uses an independent type of algorithm to verify the design work. That can catch a lot of problems such as software not able to handle certain combination of data, errors in the software... etc. Unfortunately, in EQ, you don't get that. Therefore common sense is very important. If you xover at 80hz and that is a wavelength of 12ft. So any program puts a 6 ft extra is literally inverting the phase on the sub. What I would do is I will wire the subwoofer output of phase (if there is a switch on the plate amp) and now see the results from the program. If the algorithm performs consistently, it should now remove that 6 ft distance. If not, then the problem it tries to resolve is not phase problem.

EDIT: another issue is digital latency. This applies to all digital process not symmetrically applied to all channels. My Denon 4802 has a very bad latency (defined as the delay between signal in and signal out) on subwoofer channcel as compared to other channels when I use analog mode. The reason is in their design, there is no analog domain filtering on sub. It is all done in digital domain. So it needs to convert analog to digital, then digital filtering, then digital to analog, not to mention a couple of cycles to do digital FIFO bufferring to avoid overrun errors. SO it is possible that the distance is for this. BTW, the sampling rate for subwoofer is not same as the one for front channels.

Another point is, the plots I give you are all based on close-mic measurement with the least amount of interference. When you place mic at listening position, the room mode will blur phase information and making it more difficult to extract the exact phase relation. In my view, a close-mic measurements should be very important part of EQ calibration process. With that as reference, the program would know how much is contributed to subwoofers itself, and how much is to the room. These two should be handled differently.

On a different subject, I would like to say EQ and servo IS complimentary. I one time asked the designer of Audyssey about how his program impacts the basic quality of the speaker system itself. I didn't get an answer. We all know the answer. If we think of audio components such as pre-amp, power-amp, speaker as individual components in a chain and EQ is part of it, these components cannot correct the mistake/error/distortion made by other components as there is no close loop to feedback the error back to EQ in real time. One example is, if we have a ringing in the woofer at 1000hz, one may say we just EQ it out. However, most people forget that the distortion in speaker is generated at the very last stage of this chain. EQ can control the signal passing through it, but it cannot control the distortion happen at the end of the chain. For those who reads distortion plots all the time would know, if we have a 1000hz ringing, we would get a bump in 2nd order distortion number at 500hz (because 500x2=1000), and a bump in 3rd order distortion number at 333hz (333x3=1000). The problem is still there. EQ solves part of the problem. I also think making the frequency response as perfect as possible (such as getting a very flat close-mic response from speakers and good speaker location) can make EQ algorithm easier to find an optimal solution.

[Gov]

I have owned two Pioneer receivers and everytime I have run MCACC, it sets my sub almost exactly the same everytime and almost the exact distance to my listening position as well