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09-11-2018 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,540
Joined on 05-28-2004

Post #: 26
Post ID: 25105
Reply to: 25103
The thoughts...
I has been thinking the whole evening about the subject of the ULF hardness I was experiencing today and here is my leading hypothesis. I always was pitching that a sharp order filter is a barbaric thing to do, particularly at LF. Still, here I am, using the 4th order at my ULF. The 4th order at ULF was a good thing to do in my former room where I have slow opening true 40Hz horn load with over dumped driver. I needed to modulate speed and weight at the bottom of the soft sounding horn. In my current room I have no “soft sounding horn” but I have a direct radiators that are neutral in terms of “loading”. So, I need a completely different crossover at my ULF and I might even revise the architecture and let the IB to move slightly into auditable range.  I am thinking about second order now, probably at 20-25Hz… It will be very interesting to experiment…


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
09-12-2018 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,540
Joined on 05-28-2004

Post #: 27
Post ID: 25107
Reply to: 25105
Mess…
Ok, spent a half of the nigh to working with my IB problem and discovered that everything that I do now is a complete mess.
 
First of all the crossover that I used is not what I though it is.
 
I found my old there from which I learned that I modified my crossover to fine-tune my former listening room. 
 
http://www.goodsoundclub.com/Forums/ShowPost.aspx?PageIndex=6&postID=16218
   
So, I had 4th order on one side and 3rd on another side and only God know how it sounded in combination. My desire to soften the filter is still there but I have no idea where to go with it and how high can I run my IB in compare to my woofer towers. The most complicated thing is that if I go with 2 order then I might go all the way with line-level passive filters. The tossing away the active tube crossover has own problem: I am not sure I like how my DC-coupled SS amp sound in bass. So, there are so many variables involved I have difficulty to know where to go without being wasteful. I think the best idea would be to bring a digital crossover in the game and to try to get good sounding configuration from harmonics stand point. Then render the found filter in analog passive mode and try to make all the things to sound right. I wonder if somebody locally can lend me for a month some kind digital crossover to experiment. I use to have one but got rid of it… 
 
Another thing. Overnight I connected the Milq’s bass channels to drive my IB. The Milq has no power and you do here the clipping at high volume but the harmonics are spectacular and I wish I had 100W SET to drive my IB….


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
09-14-2018 Post does not mapped to Knowledge Tree
ArmAlex
Iran
Posts 81
Joined on 02-15-2009

Post #: 28
Post ID: 25108
Reply to: 25107
100W SET
Romy maybe you could borrow the 100W SET needed for IB channel from your old times friend Tim Smile))
09-15-2018 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,540
Joined on 05-28-2004

Post #: 29
Post ID: 25109
Reply to: 25107
My new IB, the first blood, good one.
This mooring I decided to play with my infinite baffle. The mess with my analog crossover hat was calibrate for my old listening room gave me bad IB taste. I bought used stinky Behringer DCX2496 Ultradrive Pro crossover for $100 to find my new crossover point. The Behringer is a spectacular machine with all imaginable flexibility and very fast making all possible experiments and listening the results I recognized that I need to disconnect my woofer to and to run IB all the way up to my midbass channel. So, I ended up preliminary with somewhere around 52-56Hz, second order Bessel of cause. There is a lot of flexibility and ease to make all possible adjustments, I had a LOT of fun to shape my sound, I did no measurement and played purely by ears. For, the things will be revised as some measurement be made.


I am quite surprised with the sound I go. It is very good and it was VERY easy, it was kind of insulting how easy it was. The bass now fill the whole room very evenly and the sweet spot grew very dramatically. The midbass got surprisingly cleaned up, become more granular, lost some compression and become much more open. The lower octave is truly infinite, very solid and very nicely mixed with the rest of the sound, I am very surprised how easy it all come together. Probably the biggest beneficially of all is imaging, it is kind of become insane. I spend the whole morning like a pig in shit, swimming with my new sound. Even Amy flocked to my listening room and we did some listening and calibrations together.


Now, here is what I need. I mist like I stay with 2nd order and I need to nail down the specific frequency I will end up, it is important do not confuse frequency with volume.  I need figure out if it worth for me to get rid of my bass line-arrays and to give my Midbass Vitavoxes for a 1/3 octave lower. I need to review the system installation in the room from imaging perspective, this is a whole new imaging game and I am willing to cash everything that comes free with this game. I need to implement the final crossover at analog level. I do not know if it will be in the amp made as passive line-level or it will be fully active with tube buffer. The second order is very simple filter and might end up with passive line-level but I do not know if my stinky SS amp will sound Ok in bass. As now despite all superbly positive thing in the sound all bass notes basically the same: courtesy to the digital crossover and SS amplifier. I need to render my final filter at analog level and see where I will end up with lower octave notes discrimination. I might end up with some kind of PP DSET around 845 or 211 tube but at this point it would be looking too far…


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
09-15-2018 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,145
Joined on 10-12-2006

Post #: 30
Post ID: 25110
Reply to: 25109
Zobel?
Glad to hear you've found a short cut.  Of course you don't want to run the Auras too high, but the IB should allow them go go higher than they might in a box, and it should also improve the transition to the bass.  If you decide to go SET it might be nice to set the impedance?  I forget, do you still have your old ML2 LF units?  Like I said in other threads, I'd probably start with tune-able Hypex, if only because I am curious, also always a sucker for the promise of an easy fix.  This might also be fed from your DSET...



Best regards,
Paul S
09-15-2018 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,540
Joined on 05-28-2004

Post #: 31
Post ID: 25111
Reply to: 25109
Too freaking good to be true
Made today a first sweep of one channel, surprisingly good. I did not work with it; just made it to sound OK, within the context of slope (harmonics) and volume and then measured what I was listening. The flatness and depth of response is kind of surprises me. The bass towers are disengaged, one sweep is juts horns and another with IB

IB_NoBassTowers.jpg



"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
09-17-2018 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,540
Joined on 05-28-2004

Post #: 32
Post ID: 25112
Reply to: 25111
More thinking about IB and some configuration changes
There are few more observations I would like to share after listening my new IB over this weekend. 
 
The midbass. The midbass channel that is handled by a single Vitavox 15 driver with use of my new IB became if not more propitiate but at least more articulate and communicative. I am not sure why but it is quite noticeable. Since I am planning to stop driving the bass towers from my Mil’q bass channel I am planning to bring the Milq’s bass channel to drive that Vitavox driver.  This will gives a LOT of opportunity to pay with loading and to experiment with many other things. Why would believe that IU will have an extra bass channel in my amplifier! And who would feel that it is a bad thing!?… 
 
http://www.goodsoundclub.com/Forums/ShowPost.aspx?PostID=22459 
 
 The volume. To my very huge surprise the enter playback to become to sound MUCH louder at MF. As I moved to this new listening room I am always was bitching that I have no volume even though the size of my listening room did not change too much. It made me to get for active gain in preamp in some cases.  With introduction of my IB channel I got my volume back and subjectively the playback sound now twice louder. Oh, the glory of ULF channel!!!!


The bass arrays. As much as I love them but for now I am not planning to use them. The IB gave a very different type of sound and I would like to get THAT. I would never though that it would come to it and I always expected to use my bass arrays for bass and IB for ULF, or sub bass. The uniqueness of my situation is that my IB turned out to run from 5Hz to 120Hz with relatively flat response, something that I absolutely not expected. So, I was considering to bring the bass arrays to my basement storage but here is why Amy interjected and I am not sure how to deal with it now. Amy insisted that the bass arrays must stay in the listening room as she feel that it looks very pretty. Indeed, for the woman the size matters… 
 
The crossover. I will be building this week a second order Bessel 40-50Hz crossover with 12AX7 as a buffer after the filter.  I am deciding if I need to go with passive filter or to drive the filter with another active stage. Bothe will work very well. Dima calculated a filter values for me in passive mode but I wonder if I get more dynamics in I put juts in from of a filter another 12AX7. I do not have answer for this question now. Most likely I will put the two tube into the game and will make a switch that would allow me to defeat the first tube. 
IB_Filter.jpg 
 


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
09-17-2018 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,145
Joined on 10-12-2006

Post #: 33
Post ID: 25113
Reply to: 25112
"Inactive" Bass Towers in the Room
It seems likely that the bass towers would affect the sound  in that situation, perhaps eating some sound waves?  Are you going to listen with them in and out or the room, or just leave them there, no matter what?


Best regards,
Paul S
09-17-2018 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,540
Joined on 05-28-2004

Post #: 34
Post ID: 25114
Reply to: 25113
The wifey investigation.
I absolutely agree with you. The bass towers should impact imaging negatively and I feel it would be a good idea to move them out. I am still sitting on fence with this idea. Not the last point is that I kind of clandestinely envoy what is going on between my fife and the woofer towers. Any man out there is fighting with his wife for his wife to accept his speakers but my wife is fighting with me to keep the ugly woofer towers in our listening room. The situation amuses me and I am willing to investigate where will it lead…


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
09-19-2018 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,540
Joined on 05-28-2004

Post #: 35
Post ID: 25115
Reply to: 25114
The crossover is ready to go.
The crossover is built and will be testing it for the rest few days. I am sure it will do some “comforting” for my SS amp. The question I have no answer for myself if I need to use an input active stage. My preamp, having 8R output impedance can perfectly drive this crossover but it might be that the input buffer give more dynamic and lower range. Who know, I will experiment.



"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
09-23-2018 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,540
Joined on 05-28-2004

Post #: 36
Post ID: 25117
Reply to: 25112
Back to the drawing board, the question is what is next?
Yesterday I spent most of the day to play with my IB, trying to make it to sound the way how I like.  I pretty much wanted to re-implement on analog level that surprisingly good result I got with digital crossover. So, I have built my along crossover with two cathode followers, the image above. It is the same Bessel 50 Hz and I turned it on I did not like the sound too much and measuring response nit was clear why. So, I was keep sweeping the room and keep adjusting the crossover, the midbass section and the rest of the things until I go very even response for both right and left channels. I can post the sweep, it is much better then the sweep I posted above.  Basically I went with ~ 35Hz crossover that begin to roll off before the room gains at 90Hz. As I sat to listen it is was kind of huge disappointment. The magic I got with digital crossover is completely gone. The sound is even but not “fantastic” as I got initially. I can write a whole book how good and magical it was with digital crossover but with analog crossover it was just too boring to describe it. Interesting that measurement-vise the response with analog filter is way better, however, bad response with digital filter does not bother me at all.


I feel that I got hit by phase, the digital filter run perfect Bessel and it was the key. Dima feel that I got hit by harmonics and tube filters has own harmonics that did not work in my case.  His theory is supported by the fact that I hear subjectively “right” sound at 50Hz digital and 35Hz analog. I do not think he is right and I believe I know that difference between harmonics and phase. Phase give magic, harmonics give comfort.


So, I need to experiment more, I will change the tubes and will get rid of the first buffer in my crossover. I would hate to learn that I need a phase precession of digital crossover to get my “magic” back. The Behringer’s lower bass is very bad and I would for sure will not be able to live with it. There are some projects out there that change the Behringer output stages that might presumably improve the lower bass but I personally have very little experience with it or trust to the people who play with digital crossovers. I need to admit however that the midbass with Behringer was very- very good…


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
09-23-2018 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,145
Joined on 10-12-2006

Post #: 37
Post ID: 25118
Reply to: 25117
Sub Amp/XO with High Level Input?
Some Hypex-type sub amps with ULF X/Os have high level inputs.  Maybe this is a way to feed the thing from your DSET, if this is a goal for you?  I think most of this type X/O and amp combination have an input buffer, and most of them have 180/variable phase options.  From what I've heard they are no gimmie, and certainly not good when driving usual fart machines or "sledgehammers".  However, I have heard them working well enough to keep me very interested.  Perhaps in the end there is no There there; but perhaps higher demands going in could make an acceptable solution with these basic tools?



Best regards,
Paul S
09-25-2018 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,540
Joined on 05-28-2004

Post #: 38
Post ID: 25119
Reply to: 25117
Some insanity…
The twins have a horrible night, probably the last stage of teasing or perhaps we overplayed with them last night…. We took them from the cribs to our bedroom and after an hour of fighting I left Amy with Abby and took Charlie/Kai to sleep with me in my office’s bed. The poor kid is too excited and does not sleep, neither do I, thus posting at my side is the most productive thing I can do… 
 
I need to say that I am thinking a few hour a day about the dilemma I faced a few day ago. The phase setting I go with digital crossover were so spectacular that I literally flabbergasted. It was so interesting that I am afraid to plug the digital crossover back as if I do and if it again throw that stunning phase sound then I afraid that I will keep that poison thing in my system. For sure it is possible to upgrade the reasonably horrible input and out stage of DCX2496 to something better and considering that I run ONLY sub 50Hz and with no EQ of any kind it might be acceptable. I absolutely hypnotized with an ability to dial in by 1 degree timing on LF channel. I also have no idea how to live with timing luxury that DCX2496 offers and the tonal/harmonic indifference that the unit has. I have no idea of the modification of I/O would change it to the direction I want to. 
 
The biggest mystery for me and it is what I am thinking about all time is what digital filter does to my sound that analog could not. Is it a precision of the Bessel curve? I hope it is not. I hope it is something that I am still missing. One way or another I need to find is as the sound I got with analog filters is not even remotely where I would like to be.


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
09-25-2018 Post does not mapped to Knowledge Tree
anthony
Posts 193
Joined on 08-18-2014

Post #: 39
Post ID: 25120
Reply to: 25119
Have you tried...
 Romy the Cat wrote:

 
The biggest mystery for me and it is what I am thinking about all time is what digital filter does to my sound that analog could not. Is it a precision of the Bessel curve? I hope it is not. I hope it is something that I am still missing. One way or another I need to find is as the sound I got with analog filters is not even remotely where I would like to be.


Romy, have you tried a conventional non-tubed filter (say an RC filter)?  Have you measured the frequency response of the tube filter?  If the tube and digital filters are the same they will sound generally the same so my only thought is that they are not the same.
09-25-2018 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,540
Joined on 05-28-2004

Post #: 40
Post ID: 25121
Reply to: 25120
Everything is up to grabs now...
Anthony, the filter I use in the tube filter is a regular RCRC filter, there is nothing special in there. It has two buffers, input and output and it is it. The point you made is very same as I do: if the digital and analog filters are the same then what is the difference? Sure, I have the sweep from analog filter and it works fine. It might be worth to do a digital sweep and to compare the difference but something very strongly suggest me that it is not amplitude problem but phase/timing problem. The character of the sound with digital filter is like nothing that might be described at am realm domains. The sound with digital filter feels like does not stick to things and rather randomly dancing in the room with clearly updatable amplitude deviation that does not bother hearing at all. There is no other world then “magic” that I can describe it, it is almost like the playback got instantly positioned to DPoLF, at least it was the only time when I hear such a dramatic gain in quality audio reproduction….  
 
I do not so anything now and I am trying to process what happened. I have no explanation and I do not want to move or change anything to lose it. I will do one step on a time to find what was it and how can I manage it.


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
09-26-2018 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,540
Joined on 05-28-2004

Post #: 41
Post ID: 25122
Reply to: 25121
Eventualy!
OK, I have found the problem I had with my digital and analog crossovers, now everything is consistent. It turn out that my contractor why built for me the IB manifold confused the polarity of right and left channels. I was not able to use the phase tester with analog crossover as the filtration too deep and I have no access to the drivers up close.  With digital crossover I was able to bypass the filter and test the phase and everything was in phase. With analog crossover the R and L IB channels were out of phase and the reason why the digital crossover sounded so well was because my digital crossover was set to invert polarity of channel B. I discovered the problem when I made the first time sweep for both channels. 
 
So, the digital filter is gone. I end up with 35Hz Bessel and below is the response for both channels individually. I am positively surprised, (VERY SURPRISED!!!) with final sonic result I got and with relatively low amounts of efforts it took. I will work with small bells and whistles of response and tonal/dynamic (tubes, cables etc…) aspect of sound but the basics is there…

IB_BothChannals.png



"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
09-26-2018 Post does not mapped to Knowledge Tree
anthony
Posts 193
Joined on 08-18-2014

Post #: 42
Post ID: 25123
Reply to: 25122
Awesome
You said it sounded like a phase problem and it was.  Couldn't have been easier to fix either. 
Page 2 of 2 (42 items) Select Pages:  « 1 2
   Target    Threads for related reading   Most recent post in related threads   Forum  Replies   Views   Started 
  »  New  Macondo’s lowest channel...  Good highs...  Horn-Loaded Speakers Forum     148  950131  09-15-2010
  »  New  Romy The Cat's new Listening Room..  Won't be the last time he makes that trip!...  Audio Discussions  Forum     478  1874929  03-28-2010
  »  New  Getting more power from SET vs. properly distorting SS...  Sound Board...  Audio Discussions  Forum     4  32341  05-09-2011
  »  New  How to get a LOT of SET power...  Not a refrigerator but......  Audio Discussions  Forum     101  579225  02-26-2006
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