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  »  New  45Hz Bass Horn..  Can We Ever be Saved From Ourselves?...  Horn-Loaded Speakers Forum     23  314640  09-19-2006
  »  New  8" Goto Woofer for 60Hz Horn..  It's not a Goto 8in driver...  Horn-Loaded Speakers Forum     5  87176  11-03-2008
  »  New  The Macondo’s Upper Bass Channel: what is next?..  Görlich again...  Horn-Loaded Speakers Forum     30  289698  10-28-2007
  »  New  Jessie Dazzle Project..  Will this better to be auditable?...  Horn-Loaded Speakers Forum     172  1558792  08-03-2007
  »  New  Romy The Cat's new Listening Room..  Won't be the last time he makes that trip!...  Audio Discussions  Forum     478  2914093  03-28-2010
  »  New  Problems with horns: upper bass ..  Must it be about loading?...  Horn-Loaded Speakers Forum     109  1167383  03-25-2005
  »  New  Midbass Horns and Real Estate...  Just a youtube video......  Horn-Loaded Speakers Forum     247  2138046  07-26-2009
  »  New  Macondo’s lowest channel...  What truly are you tryin to accomplish?...  Horn-Loaded Speakers Forum     150  1393176  09-15-2010
  »  New  Practical Guide for Back Chambers Tuning...  Back chamber’s cost-benefit....  Horn-Loaded Speakers Forum     5  75654  10-21-2006
  »  New  Superbly interesting effect: Suspended decoupled floor ..  Superbly interesting effect: Suspended decoupled floor ...  Playback Listening  Forum     0  18029  10-08-2010
  »  New  Midbass impedance bumps -- why and what to do?..  You need to stop deceive yourself....  Horn-Loaded Speakers Forum     18  193442  10-21-2010
  »  New  Mystery of bass horn calibration: Radiating Surface Dee..  Mystery of bass horn calibration: Radiating Surface Dee...  Horn-Loaded Speakers Forum     0  17230  02-03-2011
  »  New  Impulse response, short notes and midbass horns...  A possible solution to better impulse?...  Horn-Loaded Speakers Forum     14  127844  06-13-2011
  »  New  My new “New” listening room, 2024..  That is not enough efforts in this direction....  Audio Discussions  Forum     31  17055  05-08-2024
10-12-2010 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,131
Joined on 05-27-2004

Post #: 381
Post ID: 14715
Reply to: 14702
This assumption is a tactical mistake.
fiogf49gjkf0d
 Bud wrote:
The next time you are at live music, listen specifically to this "dark side" of the live sounds. Then listen again to your system. I think it is the key to a whole new level of reality in out favorite illusion.

I was on Saturday at live concert:

http://classical-scene.com/2010/10/09/proud-to-be/comment-page-1/

and “thankfully” the BSO played badly. As the result I had opportunity to listen and to think about Sound. However, I do not compare Sound of live music with the Sound of my playback. This comparing is a fundamentally faulty objective that was invented by idiotic audio press to let their consumers to fight endlessly with lucrative windmills.

Rgs, Romy the Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
10-14-2010 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,131
Joined on 05-27-2004

Post #: 382
Post ID: 14734
Reply to: 13597
The fun time eventually.
fiogf49gjkf0d
Eventually the Second Milq is converted to work with new room and new midbass horn. Not I have the complete Melquiades/Macondo setup that is more or less optimized to work in my need room. The Sound is very pleasant and not is the fun time starts. Not I need to fine tune Macondo, to fine-calibrate the channels to make sound exactly how it needs to be.  I am extremely good with it and I extremely love it. This is extremely pleasant part of work and superbly gratifying. It require some listening, making some very minor changes with channels, very minor move or speakers and a lot of thinking.

At this point I think I need to find a way to introduce a quarter crossover slopes for my midbass. The second order is fine, the third is too short but I would like with second order a bit to hold the tail, very-very slightly. So I guess I would need to put around 200-300Hz another slope, probably with some kind ultra low DCR speaker level Inductor, like Jantzen Toroidal… Those fine refinements I will be doing for the next week or two….

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
10-17-2010 Post does not mapped to Knowledge Tree
rickmcinnis
Posts 60
Joined on 10-18-2010

Post #: 383
Post ID: 14745
Reply to: 14734
I think you would be happier with low dcR air coils at the speaker
fiogf49gjkf0d
Having tried many types of coils nothing was as transparent as the NORTH CREEK 8 gauge air core coils.

I do not think you will be happy with the JANTZEN or any other using a metal core.

They are much cheaper than the NORTH CREEK and look better. 

I, too, have used this combo approach to get a crossover curve and found it works well when one wants to avoid more amplification stages to get a sharper slope.

10-17-2010 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,131
Joined on 05-27-2004

Post #: 384
Post ID: 14746
Reply to: 14734
Something is not right
fiogf49gjkf0d
Last night Levine and BSO played a phenomenal Mahler 5, truly great play.  I had some issues with BSO sound and I probably will bring it up to them. Tonight I decided to listen the M5 broadcast for the first time and I realized that my bass is gone. I mean it became not as interesting as I remember it was 3-4 days ago when I was listening it last time attentively. I have no time to look into it now but something is not right….


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
10-17-2010 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,131
Joined on 05-27-2004

Post #: 385
Post ID: 14747
Reply to: 14745
A few howevers, as usually.
fiogf49gjkf0d

 rickmcinnis wrote:
Having tried many types of coils nothing was as transparent as the NORTH CREEK 8 gauge air core coils.

I do not think you will be happy with the JANTZEN or any other using a metal core.

They are much cheaper than the NORTH CREEK and look better.

I, too, have used this combo approach to get a crossover curve and found it works well when one wants to avoid more amplification stages to get a sharper slope.

Rick, thanks for the opinion.  I generally would agree: nothing beats air core coils. There are a few “howevers” of to look at the subject a bit deeper.

If we are use a very low crossover frequency then the air core become huge, really, a true barrel of copper. The inductance of could and driver, combined with capacitance of the cables and HUGE air coil create a perfect resonating detector. Combined with a driver high sensitivity one might pick radio stations and all imaginable noises right in this detector. So, to do the things properly as 10mH air core 8ga coil will be 15” in diameter and near 60 points in mass. Now, to shield this coil you would need ½ inch steel. The problem is that if you locate such a sarcophagus too close to the coil then the core will talk with it and you have no air core anymore. So you need to locate the shield no closer than let say 5-7” from the end of the coil. So, we are taking about a table size enclosure for a single coil. Do not forget that that I gave an example of 10mH air core 8ga coil but in my case I would need 30mH – I will not be able to lift up such a coil. Alternatively the shield might be done with co-netic like alloys that have 800 times more shielding capacity. Prepare to pay for the shield much more then you paid for the coil. That all combined with the fact that such a coil can’t effectively filter and the inductance of driver’s VC will crew up file in the driver’s peaks.

Do not forget that even 8ga coil the DCR of the coil is large as it has a LOT of wire, 10H of the air core will have .4R. The toroid coil with metal core will have literally a few turns of wire and will have DCR of .02R. You get purity or air core but you lose dumping as you have too high DCR. Also, I am pretty confident that all air-core advantage exist only at HF, at lower frequency it is very questionable.

How I know all it? I when over it, not once and it made me to feel OK with metal core for LF. In my case the main roll off will be by line-level filter but I can wire more curves in my amp. I need one very soft first order and I think line level will do fine for now. It possible to add a filer in plate voltage but it would require to change my amp that it a bit complex without it.Rgs, Romy the caT




"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
10-18-2010 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,131
Joined on 05-27-2004

Post #: 386
Post ID: 14750
Reply to: 14746
The “Amused to Death” efect
fiogf49gjkf0d
Last night it was a surreal experience, sort of  QSound–type experience. I still do not know here will be the exact location of my listening chair, it is debating with 2 feet, and because of this I did not bother to lock the Macondo’s channels in time alignment and in final fine amplitude balance. So, the Macondo’s channels are roughly in place but for the results I am after they are pretty much in random location. If cause this screw sound a lot but in case of Macondo this screw up has some intricate quality. Macondo now is not 2-4 misaligned channels the shot unsystematically buy 14 channels. This makes the error come from each channel littlie noticeable but it still creates some screw up phase effects.

For installs there are some moments in the Mahler 5 when triangles hit by a percussions in end of BSO stage but they sound from behind and above of my listening chair. In reality of my listening room it come midbass horn but it is very HF note that imposable to come into the midbass channel.  I was listening those things last night, catching the spooky bats of phase anomalies and I can say the it was almost finny feeling, but I was too high on my Cohiba from the mid of the first movement….


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
10-20-2010 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,131
Joined on 05-27-2004

Post #: 387
Post ID: 14759
Reply to: 14750
Talking about the midbass….
fiogf49gjkf0d
Despite the fact the I lost the quality of the lower knee of my midbass horn (I guess the primary resonance went all the way down) I keep trying to catch the right termination of midbass  low pass filter. I bought those expensive 20H coils and added it to the existing second order line level at 107Hz. The 20H coil formed another first order at around 120Hz. Sonically it was very bad – the whole rich midbass tail got striped and sound lost lash and richness. The 20H coil made almost the their order filter (coals with second order at line level) and it is too much .

Continuing experiments I concluded that somewhere between 3H and 5H will be the right final filter. Theoretically it would make the second crossover break at 600-800Hz . In practice, considering the high inductance of the Vitavox 15” driver and that the driver’s VC is in series with the filtering coil only God knows what the effective crossover they form. I do not bother to figure it out and to measure it but juts tune the roiling inductance by hearing what Sound does.  I know very presence how I need it to sound and how I would like the midbass decay to be.

Talking more widely about the midbass in my specific implementation I have to tell you that my upperbass horn greatly saves my ass.  Without a full duty of upperbass horn the midbass project would be a failure sonically. In fact the fine tuning the upperbass in relation to the room and to midbass is very very powerful tool to shape the sound in the whole room. This is a direct modification the size and impact by the “melody range”. Rubbing the midbass against upperbass it is possible to shape all imaginable effects the form the bone of the whole sound in the room. Playing with crossovers, plate currents (modifying damping a bit), with volumes and with the way how the lover MF (Fundamental channels) talk with upperbass/midbass it is possible to get very luxurious sound with gloriously-rich lower en. I do not have the final confederation yet but I have a few settings that I truly like. I would not have problem to settle with any of them…

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
10-22-2010 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,131
Joined on 05-27-2004

Post #: 388
Post ID: 14770
Reply to: 14746
Something is right.
fiogf49gjkf0d

 Romy the Cat wrote:
Last night Levine and BSO played a phenomenal Mahler 5, truly great play.  I had some issues with BSO sound and I probably will bring it up to them. Tonight I decided to listen the M5 broadcast for the first time and I realized that my bass is gone. I mean it became not as interesting as I remember it was 3-4 days ago when I was listening it last time attentively. I have no time to look into it now but something is not right….

As I predicted the Vitavox drivers, as they start working after years of sitting in the box, got softer and the resonance frequency dropped. Sine I recognized that my midbass lost its quality very aggressively I anticipated that the resonance dropped in 20s. I was wrong. Measuring resonance not I got 37.2Hz. That is very interesting as I did not expect the sound go so week with juts 5Hz off the mark.

I decided to move resonance back to 42Hz stopping it to work with open back chamber. Here I had another surprise – the driver was practically did not response to the presence of the back chamber cover. Before it moved resonance for 12Hz but now the driver was so soft that presence of the back chamber lid it recognized as almost open air! Funny but now I need to displace the back chamber again.

I took dense, non-compressible foam and fill ~ 30% and then 50% of the space in the back chamber with back chamber sealed from outside.  The resonance went to 38.6Hz. Not a lot I figured. However, the Sound got surprisingly better. Paying more with it I was able to drive the resonance to 39.4Hz and this is how I finally closed the back chamber for now. The sound is nothing like the last week, the sound is very good but it become good only if I set resonance over 38Hz -38.5Hz. I have no explanation for this phenomena and I did not expect that the 1-2Hz will do such a huge difference. I was thinking and thinking about it and then I got bored from it. If for whatever reason my horn and my driver want to have resonance over then I will give it to them and let them choke from their sick pleasure.

Anyhow, I have my midbass back and get some idea how my driver behaves as it ages. The moral of this story is that if you use vintage drivers with paper suspension in your horns and if you demand high level of operation and performance then let your vintage drivers to burn-in a lot and only then lock the operation of your horn.

The caT


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
10-23-2010 Post does not mapped to Knowledge Tree
el`Ol
Posts 225
Joined on 10-13-2007

Post #: 389
Post ID: 14771
Reply to: 14770
Verifying the driver choice
fiogf49gjkf0d
Romy, are you going to verify the decision of using fragile vintage drivers?
E.g. by trying JBL midbass drivers?
They would be closer to the design philosophy of the Fane Studio 8M.
http://www.jblpro.com/components/maxout.htm#2020H
10-23-2010 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,131
Joined on 05-27-2004

Post #: 390
Post ID: 14772
Reply to: 14771
The driver choose is always a quandary
fiogf49gjkf0d
 el`Ol wrote:
Romy, are you going to verify the decision of using fragile vintage drivers?
E.g. by trying JBL midbass drivers?
They would be closer to the design philosophy of the Fane Studio 8M.
http://www.jblpro.com/components/maxout.htm#2020H

The driver chooses is a quandary and it is always a question if the driver used is the ultimate driver to use. There is however a catch. For MF drivers it is easy to swap them in a MF horns with very limited adjustments of easy change a horn for different driver. With Midbass horn, as it might be seen from my experiments, the performance of the channel is greatly depends from how the drivers is used in the horn. I am not one of those who stick a random driver in a random loading configuration and then make conclusions about sound. I think to make my midbass horn to sound properly in context of my playback is a good month-long work. If I change a drive it would be another month to optimize and balance the things.

I admit that JBL 2020 looks very good on paper and might be a fine candidate for a horn like mine. In futures, what the sound I am getting in my room stop to be novelty and if I have any dissatisfaction with Sound then I might try other driver in midbass, the JBL 2020 will be fine and I have some others in my mind. That is why I made the mounting pate of the back chamber interchangeable. It will be however some work to do the experiment properly and I need to have motivation to do it, at this point I have no motivation and no matured expertise to assess the result properly.

Regarding the JBL 2020 specifically.  It might be a bit too tight for my horn. The 2020 has resonant frequency 60Hz that is a bit too high for my 42Hz horn. I would like a driver to have some LF “reserve” at the bottom and 2020 would not have in my type of horn. But you never know. It is absolutely impossible to predict how a driver will behave being loaded…


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
10-28-2010 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,131
Joined on 05-27-2004

Post #: 391
Post ID: 14803
Reply to: 14770
The final Midbass
fiogf49gjkf0d
Got the ultra low DCR toroids coil and pit them in use. Yes, it was very right move and they a bit trimmed the midbass tail. Playing with inductance and listening how the midbass decays (measurements are worthless in this case) I ended up with 4.8mH coil. Against 15R drive it is around 500Hz first order crossover. The most precisely is imposable to get for this type speakers level filter. So, I have First order 20Hz and second order at 107Hz bandpass in the amp at line level and then first order at 500Hz speakers level. This make is sort of 2.3 order filter. The sound not from the midbass horn is something that I call “proper sound”. I very much am proud by the way how I manage to integrate midbass into system. Many people tend to spend a lot of effective efforts into midbass solution and love to show it off. My horn is superbly disciplined and it goose what is called upon to do, nothing else. From a listening position a listener, even an experienced one would never say that there is a midbass horn in operation, not to mention a listener would say where the horn installed. The trick I pay with upperbass horn truly pays off.

So, the Midbass I think in it’s final stage, I do not feel that I need to do anything with it. The crossover is set, the back chamber is sealed and weatherproofed, the amplification channel is set and calibrated. I would love to raise the resonance frequency for 2-3Hz sometime in future but let see how it goes – I will return to this subject next summer. I load the bass channel to 1500R that is a very deep idling. I have superb dumping but I have all power eaten by transformer. So, if I run the output tube with less plate desolation then 55W then I get some clipping at very loud passages. Therefore I drive my bass amp pretty hard and I am considering loading the tube a little bit more and I would like to have some power headroom. This loading will come alone with a new OPT transformer with fast core. This will be a project for future.

Listening the sound all together one would be surpass how much this Sound is similar in the concept to the sound I had in my old listening room. Yes, I do feel that midbass is better in the new room but the room is many times larger. I in fact so pleased with the midbass integration that I last night “officially” invited a local audio guy to hear how nice it all turned out to be – something the I did not do since I moved in my new listening room.
The thing are getting along well and the only main thing now is to find the final proper configuration for the ULF channel/s

Rgs, Romy the Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
10-28-2010 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,131
Joined on 05-27-2004

Post #: 392
Post ID: 14805
Reply to: 14803
Official end of the midbass project…
fiogf49gjkf0d
I changed the new flash at my site to “Ok, the midbass horn project is successfully over. Over 3 months, over 400 posts, over 180 pictures… all publicly available…” The project started physically on July 16, 2010, ended on October 28, 2010. The preparation for the project took much longer - I would say that it was the last 8 years… The cost of materials in my rough estimate is around $5000. I will not disclose the cost of labor, it is a lot but frankly it is still lower then I initially expect.

During the project… The major fuckup was just one - the difficulties with accessing of the right size of back chamber. The major worry - the upper positioning of the midbass would too much localize the midbass direction.  The major success – an existence of a properly made, 42Hz midbass horn that is in time-aligned but invisible and doesn’t ruin the room décor. The major discovery - if horn has no reflections then it linearizes driver impedance. The major coincidence – the efficiency of midbass horns driven by Milq’s bass channel is identical to the Macondo’s MF reference efficiency. The major funny story – me telling to a person who inquired what I was building, informing him the I am building a “God’s Voice machine”

Now is the most interesting question: was it worth it? I do not know. I pretty much wasted a summer on this project but from another point of view EVERYTHING that we do is waste of time in one way of another. This midbass horn is something that I wanted, so I got it and I guess it made it worth and valuable to me.

Would I do it again? I do not know. I did it because THIS listening room did inspire me to have this THIS type of horn. If I move out of this room then I would need to get another inspiration. I am thankful that I did this project in my mid 40s it would be much more difficult for me to do it in 10 or 20 years…

I kept the whole project open and available for public, sharing my success and failures, blinders and brilliance, stupidity and cleverness. If nothing else, then I feel that my project extends knowledge base about midbass horns and create opportunity for the installations of others to sound better. So, in the way the torch of the horn-loading idea is still lit and now is passed to whoever have interest in it.

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
10-28-2010 Post does not mapped to Knowledge Tree
rickmcinnis
Posts 60
Joined on 10-18-2010

Post #: 393
Post ID: 14808
Reply to: 14805
The evolution of the colloidal loudspeaker
fiogf49gjkf0d
Glad to hear you have found a satisfying point so that you can listen to your system.

Certainly the low bass is not as critical to your being able to enjoy the system, although no question there is much to be gained from that being optimized.

Trying to get all of these elements to blend seemlessly is akin to the colloid and for those who require more sybstance than a single driver system can provide there is no choice but to find a way.  Most multi-way systems are not close to being colloidal.

I am inspired by your determination to get it right.  I find it easy to get close and try to listen past the flaws.  This is easier with my system since its resolving power is nowhere close to what your system is capable of.  I find your reports and your efforts inspiring and will try to be more critical with my adjustments.  I suspect I am not alone in finding something of use in this thread.

Now to read about the evolution of the subwoofer project ...

(Back to the air cores, I did not consider the impedance of your drivers assuming approx. 8 ohms)
10-29-2010 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,131
Joined on 05-27-2004

Post #: 394
Post ID: 14814
Reply to: 14805
…and the few Thanks….
fiogf49gjkf0d

 Romy the Cat wrote:
I changed the new flash at my site to “Ok, the midbass horn project is successfully over. Over 3 months, over 400 posts, over 180 pictures… all publicly available…” The project started physically on July 16, 2010, ended on October 28, 2010. The preparation for the project took much longer - I would say that it was the last 8 years… The cost of materials in my rough estimate is around $5000. I will not disclose the cost of labor, it is a lot but frankly it is still lower then I initially expect.

During the project… The major fuckup was just one - the difficulties with accessing of the right size of back chamber. The major worry - the upper positioning of the midbass would too much localize the midbass direction.  The major success – an existence of a properly made, 42Hz midbass horn that is in time-aligned but invisible and doesn’t ruin the room décor. The major discovery - if horn has no reflections then it linearizes driver impedance. The major coincidence – the efficiency of midbass horns driven by Milq’s bass channel is identical to the Macondo’s MF reference efficiency. The major funny story – me telling to a person who inquired what I was building, informing him the I am building a “God’s Voice machine”

Now is the most interesting question: was it worth it? I do not know. I pretty much wasted a summer on this project but from another point of view EVERYTHING that we do is waste of time in one way of another. This midbass horn is something that I wanted, so I got it and I guess it made it worth and valuable to me.

Would I do it again? I do not know. I did it because THIS listening room did inspire me to have this THIS type of horn. If I move out of this room then I would need to get another inspiration. I am thankful that I did this project in my mid 40s it would be much more difficult for me to do it in 10 or 20 years…

I kept the whole project open and available for public, sharing my success and failures, blinders and brilliance, stupidity and cleverness. If nothing else, then I feel that my project extends knowledge base about midbass horns and create opportunity for the installations of others to sound better. So, in the way the torch of the horn-loading idea is still lit and now is passed to whoever have interest in it.

I forgot to drops a few thanks to the folks who helped me with my midbass project.

The biggest thank you goes to Sergey Konovlev – my carpenter who reconstructed the attic, measured the spaces, developed AutoCAD plans, constructed horns, lifted them up, installed them, built supports and followed up with finishing the walls. He also, was a sole listener of my bitching and my assessment that he does something wrong.  In the end of the project before hosting the horns, when we were guessing if the horn will fit the narrow hole inside with less than an inch clearing I decided to make the process interesting and promised $1000 bonus if the horns fit. I will tell you that you never saw a Jew boy who was so happy to give away $1000 as I was after the horns did fit perfectly.

I would like to thanks Pablo Cheline, my local guy, who moved the horns around and helped with insulation work. A thank you goes to Bruce Edgar with whom I consulted a few times during the project and from whos experience I took some inspirations. A thanks goes also to Jeffrey Jackson who it the beginning of the projects consulted me about the materials, glues and assembling techniques. And of course the special thank goes to John Hasquin with whom I consulted during initial planning stage. Despite that John was not engaged while the project was in progress but his upperbass horn very much save the midbass, not to mention that I always have a warm feeling about John’s judgments.

There is something that is not visible besides all those posts, picture and public thought – the level of anxiety that the project brought in my regularly quite habitual life. The last crumple days before the raise the horns I got it a bit personal and was in way very psychotic.   The last 3-4 days I did not go anything besides working on the horns and did not think about anything else beside “what else my horns need”. The very last night before the hoisting the horns I did not sleep and I cough myself at 4AM on the morning waling across my listening room, patting the horns and telling them that “everything will be all right”.  Despite of that binding experience and certifiable behavior I have no particular feeling about the midbass horn now. They are in the wall, they do what they need to do and they do not bother me. I think that this type of “out sight -out of mind” approach works very good for loudspeakers….

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
11-01-2010 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,131
Joined on 05-27-2004

Post #: 395
Post ID: 14820
Reply to: 13597
Properly-operating amplification for midbass channel.
fiogf49gjkf0d
This week I will be trying to address why the Milq midbass is clipping. This is very interesting one.  Currently the Melquiades LF channel uses an output transformer 700R to 5R or 11.83 to 1. I thought before that I have much lower ratio, like 5:1 but I was mistaken. So, my 6C33C driven with 200V at 200mA is loaded with over 2100R, considering that it drives 15R driver. This is insultingly-idle operation mode for 6C33C; the tube is not loaded at all. The channel sound fine but at the max volume (when it VERY laud in the room) it clips very aggressively. Adding current to the output stage and ruing the 6C33C at 50-60W plate dissipation (250-300mA) completely eliminate clipping but the interesting question would be by. With such a idle loading of the output tube the clipping will be by deficiency of voltage. So, why adding current (and consequential drop voltage – Melquiades is not regulated) helps against clipping? I need to find the answer.

I need to find the answer as the clipping might not be where I think it is. I did not measure the amp driving my midbass channel but I will not. The clipping might be in the driver stage screen or anode or in output stage screen or anode. I need to find where it is and what clips first – current or voltage and then to reset the operation point or output tube to assure that I get max power from it. I know that I but a LOT of power and gain in output transformer. Any 6C33C amps that you see out there load this tube to 600R-800R but I load it to over 2100R. If I use this loading and run full range amps then it would be absolutely unlistenable, with all harmonics eaten and upper range brutally aggressive and even deformed. Here is however where the DSET advantage come – the channel has no upper range and in my view the super idle loading of the midbass horn is desirable. I am not sure the degree however, I might went a bit too far (as I tend to do) and loading of let say 1500R would be more appropriate. This would give some midbass “gloom” but I need to examine if it is what I want as it might change a few other things (like crossover order on ULF, like crossover order  and cut off point on upperbass and a few other parameters). I have 700R to 8R transformer or 9.35 to 1 and I might engage it. It will load the tube a bit harder and will give me a few dB of gain and power. I might as well to get another 9:1 transformer with a fast core. With this upperbass channel it is not “open bottom” channel anymore and I do not need a huge inductance on it, in fact the channel has 20Hz high pass filter.

So, I need to find what the channel clips at 40W on 6C33C plate and how can I reset to assure the optimal operation of the Milq bass channel. I think now I use no more that 1-2W from 6C33C, with the same effect I could drive my midbass from type 45/2A3 tubes. I will be posting the findings…

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
11-01-2010 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,644
Joined on 10-12-2006

Post #: 396
Post ID: 14822
Reply to: 14820
Take a Look at Power Requirements
fiogf49gjkf0d
Romy, are you  saying you are squeezing up to 60W from the 6C33C, and the mid-bass is still clipping?!?  There must be a better way than cranking still higher plate dissipation!

If you need more than 60W from the 6C33C for mid-bass now, perhaps it is time to take another look at the output scheme, at least the amplification stages?  You might get by with greater efficiency; or you might just need more line gain for more power at the tap.  I understand what you are saying about limiting frequency response, but it is still hard to believe the 6C33C sounds its best - including LF - when it is that wide open.

I remember you would not consider parallel output; but maybe this is a case where you could kill two LF birds with one lower-output-impedance stone?

Best regards,
Paul S
11-01-2010 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,131
Joined on 05-27-2004

Post #: 397
Post ID: 14823
Reply to: 14822
I do not want to lose the “too idle” mode on 6C33C
fiogf49gjkf0d

 Paul, what are you talking about? I use from my 6C33C no more then 1-2W. The 6C33C at LF might give 20 W but it is load over to 600R. I load it to near 2500R (11.83:1 transformer with 15R driver) – you figure out your how much power and gain I burn in the transformer. I do not want to have more line gain; in fact I would like to have less line gain but instead to add some gain via transformer. It is sad that I do not have tabs on it.  What I do not know is why adding current help to get rid of clipping if the tube runs at voltage deficiency. Anyhow, I need to find a good balance between the losses in transformer and attenuation in my line level.  I do not want to lose the idle mode of my 6C33C operation as it sound very good for bass. I might go for 1500R loading but with fast core:

http://www.intactaudio.com/forum/viewtopic.php?t=1085

but there are some other consideration that I have in my mind. I do feel that I a bit idle the 633C too aggressively but it might be why my hyperbolic horn does not sound “hyperbolic bass” but rather as “tratrix bass”. You never know where you will find and where you will be lose….

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
11-01-2010 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,644
Joined on 10-12-2006

Post #: 398
Post ID: 14824
Reply to: 14823
Plate Dissipation; Current Thinking
fiogf49gjkf0d
Romy, of course I know your horn is very efficient, and of course I do not mean amp output but plate dissipation, just as you did when you mentioned 50 - 60 W.  So, why the hell would that output tube clip into 1 Watt load?  I would be wondering, too!  Obviously, the energy is there at the output tube to begin with, and it is going somewhere.  If driver impedance is compatible, and it stays flat over its range, then where is the sink? With big motors, I always think, add current.

I forget if this channel has the super-long cables.  If so, have you checked the load with the cables included?

Best regards,
Paul S
11-06-2010 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,131
Joined on 05-27-2004

Post #: 399
Post ID: 14876
Reply to: 14823
How much more can I let it go?
fiogf49gjkf0d
Today I spent many hours trying to remove large LF transformers from Melquiades belly and replace them with another one that would load my 6C33C a bit harder. I do idle my output tube very hard and my objective was to get to let it go slightly.  The problem that I heard is that the amps had no power – I was burning all power in transformer.  I want to care 0dB at 40Hz at 50W on 6C33C with no clipping – in my old configuration I was not able to do it. Also, I felt the harmonically sound from midbass horn was good but sometimes it was too controlled. I would like to have more bloom, not a lot but more.  I had 11.83:1 and I replaced it with 9.3:1. It is still VERY much idea operation for 6C33C driving 15R but I very little pulled it back and got 2dB of headroom.

The result was nothing shorn of sensational – it was exactly what I was looking for. The horn got a slightly more harmonics and become warmer and more affluent. I’m much more comfortable with this sound. It still does not have this stupid bathtub sound that most of bass horns have out there and my notion to fight with midbass horn possible honk by idling out output stage still works great but it is up to the right degree and right balance. I do not know how much more I might to go into output stage loading but I think that I am approaching to very good configuration.

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
11-08-2010 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,131
Joined on 05-27-2004

Post #: 400
Post ID: 14890
Reply to: 14876
The next steps of progress.
fiogf49gjkf0d
Since I change the transformer I picked some harmonics and now I feel that my midbass has a bit too long roll off. I moved the second low pass filter close to the first filter. After a very careful listening and some thinking I ended up with setting of second filter at 130Hz. So, I have a full second order at 107Hz and then buffered first order at 130Hz, or effectively almost a 3rd order. The playback is incredibly sensitive and reacts to a 1dB and to 10Hz of crossover incredibly sharp. It is VERY interesting to set the precise operation of the midbass horn as it is possible to setting its operation incorrectly and to make sound to be better in many aspects better and more enhanced then it is.

I am sure that in the end my horn will be operating properly but as now I see a problem with my configuration. The demands of going over second and half order crossover made me to feel time delay on midbass.  So, I in way with 18dB per octave am losing my time alignment. I still think how to deal with the problem…

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
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