Official Rythmik Audio Subwoofer thread - Page 936 - AVS Forum | Home Theater Discussions And Reviews
Forum Jump: 
 3292Likes
Reply
 
Thread Tools
post #28051 of 28054 Old Yesterday, 10:14 PM
AVS Forum Special Member
 
DonH50's Avatar
 
Join Date: Feb 2010
Location: Monument CO
Posts: 9,653
Mentioned: 23 Post(s)
Tagged: 0 Thread(s)
Quoted: 1809 Post(s)
Liked: 1348
Wow, this thread has really wandered off... I actually did quite a bit of wading through the MQA papers and the looong article about it and generally understand the scheme. It's actually a fairly neat idea. Whether it sufficiently improves the sound and provides enough compression (loss, file size reduction) to become popular as a solution (i.e. beat out its competition) remains to be seen. Seems pretty far outside the scope of this thread, however. Ditto the never-ending Audyssey vs. Dirac Live vs. whatever room compensation scheme discussions. I have AVRs around the house with Audyssey, Dirac Live, MCACC, and YPAO at the moment. They all have their pros and cons. My main system is currently using Dirac Live for whatever that's worth.

Curious: Did Enrico or Brian ever confirm whether or not a DSP is inside a Rythmik sub? And if so what it is doing? My memory of discussions with Brian years ago are that it was all analog but I could well be wrong. Senility sucks, except I can re-read an old book or re-listen to some old music and it's all new again.
abd1 likes this.

"After silence, that which best expresses the inexpressible, is music" - Aldous Huxley
DonH50 is offline  
Sponsored Links
Advertisement
 
post #28052 of 28054 Old Yesterday, 11:11 PM
AVS Forum Special Member
 
rcohen's Avatar
 
Join Date: Feb 2005
Posts: 3,010
Mentioned: 30 Post(s)
Tagged: 0 Thread(s)
Quoted: 1246 Post(s)
Liked: 544
Quote:
Originally Posted by DonH50 View Post
Wow, this thread has really wandered off... I actually did quite a bit of wading through the MQA papers and the looong article about it and generally understand the scheme. It's actually a fairly neat idea. Whether it sufficiently improves the sound and provides enough compression (loss, file size reduction) to become popular as a solution (i.e. beat out its competition) remains to be seen. Seems pretty far outside the scope of this thread, however. Ditto the never-ending Audyssey vs. Dirac Live vs. whatever room compensation scheme discussions. I have AVRs around the house with Audyssey, Dirac Live, MCACC, and YPAO at the moment. They all have their pros and cons. My main system is currently using Dirac Live for whatever that's worth.

Curious: Did Enrico or Brian ever confirm whether or not a DSP is inside a Rythmik sub? And if so what it is doing? My memory of discussions with Brian years ago are that it was all analog but I could well be wrong. Senility sucks, except I can re-read an old book or re-listen to some old music and it's all new again.
Reading your first paragraph made me consider replying "You're welcome to change the subject," but then you did.

No, I didn't see any official response to the DSP question, just speculation from guys like me.
rcohen is offline  
post #28053 of 28054 Old Today, 12:29 AM
AVS Forum Special Member
 
enricoclaudio's Avatar
 
Join Date: Aug 2005
Location: Houston, TX
Posts: 2,676
Mentioned: 41 Post(s)
Tagged: 0 Thread(s)
Quoted: 1120 Post(s)
Liked: 1150
Quote:
Originally Posted by DonH50 View Post
Wow, this thread has really wandered off... I actually did quite a bit of wading through the MQA papers and the looong article about it and generally understand the scheme. It's actually a fairly neat idea. Whether it sufficiently improves the sound and provides enough compression (loss, file size reduction) to become popular as a solution (i.e. beat out its competition) remains to be seen. Seems pretty far outside the scope of this thread, however. Ditto the never-ending Audyssey vs. Dirac Live vs. whatever room compensation scheme discussions. I have AVRs around the house with Audyssey, Dirac Live, MCACC, and YPAO at the moment. They all have their pros and cons. My main system is currently using Dirac Live for whatever that's worth.

Curious: Did Enrico or Brian ever confirm whether or not a DSP is inside a Rythmik sub? And if so what it is doing? My memory of discussions with Brian years ago are that it was all analog but I could well be wrong. Senility sucks, except I can re-read an old book or re-listen to some old music and it's all new again.
Quote:
Originally Posted by rcohen View Post
Reading your first paragraph made me consider replying "You're welcome to change the subject," but then you did.

No, I didn't see any official response to the DSP question, just speculation from guys like me.
No DSP inside our subwoofers. Why? Here is Brian's explanation about this particular topic:

Quote:
Originally Posted by Rythmik View Post
I know these guys you mentioned all have credits. But I also have credit. I have a Ph.D in electrical engineering. So you need to understand why I said what I said.

DSP is good, but is not perfect. There was a company that claimed they can make a NHT speaker generate a perfect impulse response. I visited the company's booth in CES and asked the engineer just one simple question, does that mean the true quality of the speakers is no longer important? He refused to answer my question in front of other customers and wanted me to go away. The truth is like this. First, all speakers have characteristics changing between small signals and large signals. What is a bad speaker? A bad speaker is a speaker exhibit wild difference between small signal characteristic and large signal characteristic. Does the DSP fix the small signal characteristic or the large signal characteristic? DSP is a linear operation, it cannot fix both. But servo can fix both. Secondly, you know the car you drive does age and its feel is difference when it is cold vs when it is hot. Why do you think the subwoofer is any different? When it ages, the frequency response also changes. Does the DSP correct that? No. When the voice coil in the subwoofer is cold vs when it is hot, the frequency response is also different. Some called it thermal compression. I prefer to call it thermal memory effect. What is memory effect? If you press a memory foam, you will notice the impress takes some time to recover. The thermal effect on voice coil works the same way. You will hear the term thermal stress very often to explain how a voice coil can be fried. Now think of how the thermal comes and goes in voice coil. Does DSP correct that? No. Some subwoofers have such as poor memory effect, people think the subwoofer sounds slow with respect to the other channels. That slowness is a profound characteristic. Otherwise, all we have to do is move the subwoofer closer to us to correct it. Lastly, we all heard the term "unit-to-unit" variation. I can even extend that to "batch-to-batch" variation. How many times people find the actual frequency response is different from published spec? In fact, these variations do exist and is the explanation of what had happened (assuming the manufacturer does not make up the spec in the first place) . How does DSP address that? It cannot. Do you really think they will give each batch a different DSP correction? That will only create more service problem. As a result, you will see some frequency response measured by third party that does not look like smooth curve at all. It is a clear indication that imperfect EQ has been applied and as a result wavy frequency response is measured, especially when the reviewer pick a random unit from the market place without manufacturer's acknowledgement. It is imperfect because the correction is only valid to the sample unit in engineer's hand. If they find the production units are different from the sample unit, what do you think they will do? You would have guessed it right. Ship it. The customers will buy that DSP rubber stamp. Servo is different. It is a closed loop feedback system. It takes the unit-to-unit/batch-to-batch variation into account and adjust the needed correction. So now you can guess how can DSP generate a perfect impulse response? It can, but only at one particular level that the engineer samples. That is the reason I was sent away because the R&D already know the limitation. If TV is selling that DSP to me, I will chanllenge the same thing. DSP only works with the assumption of a model. Who double check if the model is correct? If no one does, it is just a rubber stamp. Not only that, you know that two bad characteristics in the system, instead of just one.

Now in terms of amplifier class, we also use class-D amplifiers. So I don't think there is a problem with class D amps. But I do think the transformer based amplifiers will sound better in bass and the argument does not come from weight. It is more from the technical difference if you care to understand. In your transformer-based design, the wall power goes to the transformer first and is rectified and then pass to large power capacitors. These capacitors gets charged at a rate of 120hz. Now even though I say it is at 120hz, the actual charge time is only 1/10 of the 120hz (or about 1ms duration). For the other 9/10 of the 120hz cycle, the energy comes from the power caps themselvs only (as if the wall power is gone). Moreover, you notice that the bass frequency we talk about, say 20hz, takes a span of 6 charging cycle. This is how you notice the bass signal can have a different impact than a 1khz signal on the power supply becasue the latter can be completely covered in one charging cycle. Now the most important thing for us to take note is there is no resistance between the power capacitors and the power supply of the amplifier because it is just a wire connection. So the power amplifier can take whatever is in power capacitors without restriction. So much as that I can short the power amplifier's power supply to get the max amount of current. To be more precise, I can short the power amplifier supply and the power supply unit can still survive. Not only that, you can get an electrical arc if you do with a contact, confirming the current supply is almost infinite. Certainly we don't want to do it too many times. But in short it will not be catastrophic. Now for the SMPS (switching mode power supply), the transformer sits after the power capacitors. So when transfer energy from power capacitors to the amplifier it goes through these components: MOSFET, transformer, and then rectifier. All of these components create IR drop (current times resistance) which restricts the current flow. Now try to short the power supplier of SMPS. Not only you can destroy the SMPS, you will never see the same electric arc because the current is limited. In short, it just does not supply the current in a snap.
Here is the link to Brian's post back in 2015:

Official Rythmik Audio Subwoofer thread
Matt2026 likes this.



Enrico Castagnetti @ Rythmik Audio
Media Room: Ascend Acoustics Sierra Towers w/ RAAL, Horizon w/ RAAL & Sierra 2s | Rythmik F12SE (x2) | Marantz SR7008 | Parasound Halo P5 | Emotiva XPA-3 & XPA-200 | Oppo 105D | Sony HW40ES |
Desktop: Dynaudio BM5 mkIII | Rythmik L22 | Apogee Quartet | 27" iMac|
Bedroom: B&W 685 S2 | Rythmik LVX12 | Marantz NR1606 | Emotiva XPA-200 Gen 2 | Samsung UN50JU6500 |
enricoclaudio is offline  
 
post #28054 of 28054 Old Today, 02:20 AM
Senior Member
 
Player3's Avatar
 
Join Date: May 2013
Posts: 315
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 78 Post(s)
Liked: 81
Quote:
Originally Posted by abd1 View Post
Funny, I was looking at your system in your signature and thinking that you have a really nice system (lurking for an XMC-1 myself), except that you should get rid of your RA subs and try some Rythmiks! Then I read your post and that's what you did! I had a RA BPS-212 and switched to a Rythmik LVX12 and the difference was astounding. So much so that I'm preferring listening to music in my theater room with the sub now compared to my 2-channel system, and movies are awesome. I'm in the middle of watching Sicario and the soundtrack in that movie just sucks you in and adds so much intensity. I love it. Looking forward to hearing your thoughts.
That's encouraging to hear! I'm hopeful I'll have a similar experience.

Emotiva XMC-1 and Emotiva XPR-5
Ascend Acoustics Sierra Tower and Horizon with RAAL
Atlantic Technology SR2200 Surrounds
2 x Reaction Audio Echo 18 XL
Panasonic 65" ZT60
Oppo BDP-105
Player3 is online now  
Sponsored Links
Advertisement
 
Reply Subwoofers, Bass, and Transducers

Tags
f12g subwoofer , lv12r , Rythmik , Rythmik Audio , Rythmik Audio F12 Direct Servo Subwoofer , Rythmik Audio F15 Subwoofer , servo sub

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off