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  »  New  45Hz Bass Horn..  Can We Ever be Saved From Ourselves?...  Horn-Loaded Speakers Forum     23  315365  09-19-2006
  »  New  8" Goto Woofer for 60Hz Horn..  It's not a Goto 8in driver...  Horn-Loaded Speakers Forum     5  87437  11-03-2008
  »  New  The Macondo’s Upper Bass Channel: what is next?..  Görlich again...  Horn-Loaded Speakers Forum     30  290633  10-28-2007
  »  New  Jessie Dazzle Project..  Will this better to be auditable?...  Horn-Loaded Speakers Forum     172  1562966  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  2925295  03-28-2010
  »  New  Problems with horns: upper bass ..  Must it be about loading?...  Horn-Loaded Speakers Forum     109  1170572  03-25-2005
  »  New  Midbass Horns and Real Estate...  Just a youtube video......  Horn-Loaded Speakers Forum     247  2144247  07-26-2009
  »  New  Macondo’s lowest channel...  What truly are you tryin to accomplish?...  Horn-Loaded Speakers Forum     150  1397212  09-15-2010
  »  New  Practical Guide for Back Chambers Tuning...  Back chamber’s cost-benefit....  Horn-Loaded Speakers Forum     5  75963  10-21-2006
  »  New  Superbly interesting effect: Suspended decoupled floor ..  Superbly interesting effect: Suspended decoupled floor ...  Playback Listening  Forum     0  18102  10-08-2010
  »  New  Midbass impedance bumps -- why and what to do?..  You need to stop deceive yourself....  Horn-Loaded Speakers Forum     18  194158  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  17284  02-03-2011
  »  New  Impulse response, short notes and midbass horns...  A possible solution to better impulse?...  Horn-Loaded Speakers Forum     14  128276  06-13-2011
  »  New  My new “New” listening room, 2024..  That is not enough efforts in this direction....  Audio Discussions  Forum     31  18110  05-08-2024
06-02-2013 Post does not mapped to Knowledge Tree
noviygera


Chicago, IL
Posts 177
Joined on 06-12-2009
Post #: 441
Post ID: 19423
Reply to: 19422
Humidity
fiogf49gjkf0d
Is it possible that over last two years, the humidity difference (or change) has been setting in both driver and midbass wood horn structure? This can be tested. Install a dehumidifier in your attic and run for a month, listen to change in sound.
06-03-2013 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,155
Joined on 05-28-2004
Post #: 442
Post ID: 19426
Reply to: 19422
Trying to do it with less blood.
fiogf49gjkf0d
Paul, Alinco magnets perfectly able to drop a charge "just like that" and I presume that it is what happened. If cause the environmental difficulties would not do it alone, at least for that time. Over winter I had output tubes worn up on both amps and as 6C33C begin to die they did the “pinging”. The pinging is outburst of energy that mostly likely near DC signal and DC discharges Alinco very aggressively.  Saying that, I’ve been observing this behavior of 6C33C for years I need to say that I did not see that impact the pinging had to drivers. However in my past the drivers were MF driver and I never had Alinco on bass. So, it very much might be that my drivers got demagnetized. I can’t to be sure however and I can stick as now my gaussmeter to anywhere and I do not know how a discharged Vitavox sound. It feels like the long decay from discharged driver but I it is mostly because I have no other explanation and because I did observed somewhat similar effect with other driver, not bass drives, however.

Jessie, to re-magnetize the drivers is very simple, in my case the key would be to do it in place as to remove driver from attic is pain in ass. I would need to figure out the polarity, wind some 1-2GA wires around the magnets and lead those wires outside the back chamber. Then get some 3-4 Farad, high discharge current capacitors bank and run the capacitors through the wires with some kind SS or mechanical switch. There are no needs to remove any membranes; all you need to do is to disconnect VC to make sure that any inductive current would not have room to flow.
 
For sure it is perfectly doable but that itself would be a big project, not to mention that I am sure that the re-magnetizing has some own kinks about which I am not informed and that takes time to learn. So if I chose to do so then I would need some kind of objective evidence that the de-magnetizing allegations are correct. I do not have that evidence as now. A friend sent me email suggesting that it could it be just that the decay time for the room has changed for a frequency range. It is possible but why it did it with upper knee of my midbass horn but did not affected anything in lower knee of upperbass horn?

Well, there is another option - try to find another non- Alinco driver, let say ceramic or Neodymium that would be more or less immune to de-magnetizing. Well, this is whole different subject as to addition of those driver is figure out how they would behave in my horn would take literally half-life.

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
06-03-2013 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,155
Joined on 05-28-2004
Post #: 443
Post ID: 19428
Reply to: 19426
Recharging the Alnico
fiogf49gjkf0d
Well I was thinking how I can verify that my midbass drivers had sunk magnets. I can take one of the drivers off; take them apart and compare them with another of my Vitavox 15 inchers. I can measure the magnetic force in the gap and it will be objective. However, no one knows if the other drivers that I have are fully charged and I do not know how much it has to be: 12.5T, 1.4T, 1.6T? who knows, I might call to Vitavox Mike to ask perhaps…

Another option would be to get a devise to read BL, a weak magnet will lower value.

http://www.daytonaudio.com/index.php/dats-dayton-audio-test-system.html
 
Usually 15-17 would consider low BL and 21-24 high BL. What would be the right BL for the 50 year old driver? Hmmm, who knows…
The most that piss me off in this whole story is that I might get all over it and recharge the driver but the reason why I have more HF from horns then I used to have will be some kind of other little stupid thing the I overlooked…. The recharging the Alnico after 50 year would never hurt however…

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
06-03-2013 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,155
Joined on 05-28-2004
Post #: 444
Post ID: 19429
Reply to: 19428
How nice!
fiogf49gjkf0d
Oops, I just learned that at the NEW Vitavox site there is all data I need:

http://www.vitavoxhifi.co.uk/pages/pdf1.php

The fully charged BL is 19.6, how nice….

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
06-03-2013 Post does not mapped to Knowledge Tree
rickmcinnis
Posts 60
Joined on 10-18-2010
Post #: 445
Post ID: 19430
Reply to: 19429
Certainly not an expert (as you know) but ...
fiogf49gjkf0d
Boston had a cold winter this year.  Well, you have a cold winter every year!
I could see that an alnico magnet in an attic, which I assume is not heated, could be affected by the cold.
Have you ever monitored the temperature in the attic?
For that matter the heat build up in the summer could be taking its toll?
Just what you need a climate control system for your attic drivers!
From what I have learned about re-magnetizing it is unlikely, as resourceful as you are, that you can do this yourself.
Bite the bullet, take them out and send them to GREAT PLAINS AUDIO who will do it for you for a pittance.
They know what they are doing with vintage drivers.  
I would send both of them as I suspect is your intention.
Hope all is well, other than having weak woofers.
Take care,
06-03-2013 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,155
Joined on 05-28-2004
Post #: 446
Post ID: 19431
Reply to: 19430
Planning and wishing..
fiogf49gjkf0d

Well, there are a few places that can re-charge the drivers, GPA can do it for sure but it is not practical in my view as to remove the drivers from attic horns and to ship them is more pain then to pay to GPA $20 to re-charge them. The re-charging is truly not so difficult posses and I would like to do it in place. I do not see myself to send the drivers each year but I do not mind to do once a year in house firework and to re-charge the midbass magnets. Also, there is an attitude thing: the assholes who recharge the drivers never give you the measurable data of magnetic force before and after. I call them assholes as the last time I sent my S2 to be recharged I did explicitly requested the numbers before and after and I did paid extra to do the measurement. The guy who did it told me that he “just forgot to measure it before”. Thank you very much, the moron! I wonder if he goes under knife to a medical procedure he ask his doc some evidence that he is in fact sick?

Anyhow, I need to find at some old supply sale some used chip device like this:

http://www.magnet-physik.de/fileadmin/Mediendatenbank/1_Produkte/1_Magnetisiertechnik/IM-M_e_2121.pdf

Then I will be able to do something like this but skipping the ugly part with caps, charges, and commutation…

http://www.audioheritage.org/vbulletin/showthread.php?6406-Loudspeaker-magnets-magnetizing-fixture&highlight=magnet+charger

The Vitavox magnets are well exposed and I will wire 20-30 turns of thick wire and I think I will be fine. All that I will need to do is figure out the polarity of the coil, I am still thinking about it. BTW, would it be possible to rent such a magnetizing devise? It probably cost 2-3K it means that it might be rentable for $50 a day. That would be phenomenal!

Meow?

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
06-03-2013 Post does not mapped to Knowledge Tree
rickmcinnis
Posts 60
Joined on 10-18-2010
Post #: 447
Post ID: 19432
Reply to: 19431
Well, if anyone could ever do this ...
fiogf49gjkf0d
It would be you!
I should have known you had researched this more than the posts revealed.
I know I would not want to wrestle those drivers out of the attic, either.  I figure you have replacements to use temporarily so you would not be without, but ...!  Now one must consider wrestling that contraption up there ...
It is amazing how people will tell you they will do something and then, after you have received them back you get the "Oh, well, we forgot" response.
I got some chokes from SOWTER to be used as a passive low pass filter and asked them to measure them before shipping since I do not have the equipment to do it.  "OH, YES, that is no problem", they say at the time of the order.  Of course, when I got them I had to write and ask what the values were and, well, ...
When you master this process, and I am lucky enough to make a pilgrimage I will bring a pair of drivers that need the treatment.  I would love to see this!
(Have you watched THE VANISHED EMPIRE?  It has become one of my favorites.  I am curious what you might think of it. Not as cerebral (by a long shot) as Tarkovsky but a very honest film)
Take care,
06-03-2013 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,155
Joined on 05-28-2004
Post #: 448
Post ID: 19434
Reply to: 19419
What was absolute wonderful…
fiogf49gjkf0d
I would like to share that wonderful experience I had 2 nights back when I spent the whole night to juts to listening my midbass horns. I did not do it for two year or so and to hear juts the midbass back as I did it during the post-contraction was very didactic. There is nothing as educational as to play one or two horn with just 40- to 107 Hz and think about the colors, density, shape, structure, texture of the sound they create. I would live all the rest observation of what I observed with me but there was one that strikes me as never before – the direction. Again and again I am applauding to myself with that super kinky decision to put the midbass in the hidden view above and behind the listening position. As I was listening the low octave coming from the horns I did very clearly hear them as the direct source FROM the front of loudspeakers.   There was some room diffusion of chose but the main midbass image was coming from front. Apparently the longer wave were shooting across my 27 feet room and bounce back to me. What was a brilliant idea to hide the horns where they do not bother anybody and where they secretly do their duty! If I even move and will be ever rebuilding my room then I would very much try to mimic something like this. The living experience in listening room will be VERY much different if I has even single 7-8 feet horn sitting on my laps.

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
06-03-2013 Post does not mapped to Knowledge Tree
rickmcinnis
Posts 60
Joined on 10-18-2010
Post #: 449
Post ID: 19435
Reply to: 19434
There is much to be learned from listening to one driver within its range and ...
fiogf49gjkf0d
wide open, just to hear what it does with either condition.
It is illuminating and surprising, especially the first times, you hear, in one case, how it divides up the spectrum and in the other case how the driver responds above the range you intend to use.  With the filters we both use there is plenty of them left in the mix well beyond crossover
As if I am telling anyone on this forum something they do not already know.
There is no question the attic horns are elegant, they are beyond simple brilliance.
Now for you to make your basement into horns for the lowest frequencies.
There has to be, at least, one giant project!  (I wish I had a basement)
06-04-2013 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,155
Joined on 05-28-2004
Post #: 450
Post ID: 19438
Reply to: 19434
God, what a remarkable idiot I am!!!
fiogf49gjkf0d
Unbelievable idiot!

Last night an audio guy visited me and I played to him some music. I was not sitting in the listening spot but what stroked me was now stringent and how shallow the playback sounded. I was waling around the listening room, scratching my back a wondering what the hell is going on. The electricity is great recently but sound is not elegant as I am accustomed to. Listening more and more I suddenly realized that I do not have my bass. I have my soft and nice midbass but I did not have my last exhale of Macondo that I am so proud off. Then to my shame I realized that that meters on my ULF power amp are not moving.  Reaching back and tracing the cables I learned that the ULF crossover was just disconnected. A month  or two back, when I connected the small Pilot speakers with own amps I did not have empty output on my preamp and I unplugged the ULF crossover to use the  Pilots. So, I do not use ULF for good tow months.

Putting back the ULF was like coming back home. The long decay of my midbass does not sound so horrible anymore, apparently the ULF, kicking at 20Hz does moderated the midbass decay. I still feel that there is a very very minor midbass decay issue but it no nears close to what I am experienced lately.

The playback again sound spectacularly and the re-charging of the drivers project is  not at my radar anymore.


I need to look further into the midbass and ULF interaction as it is very interesting subject.

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
06-05-2013 Post does not mapped to Knowledge Tree
rickmcinnis
Posts 60
Joined on 10-18-2010
Post #: 451
Post ID: 19443
Reply to: 19438
I have noticed a similar phenomenon
fiogf49gjkf0d
And thought it was in my head.
Not that I have infra-woofers ...
When listening to the individual parts of my system I had noticed that when the 75 hz horns were played by themselves there is a bloat in the 100 hz region that goes away when the subwoofers are returned into the system.
It is not related to relative phase because with either polarity the bloat would go away so it is not simple cancellation.  Of course, it was different eac way, but ...
Seems if the waveform is not put back together, even if imperfectly put back together, something goes wrong.
So I think this affects frequencies even higher than where you experienced it.
Good news that you no longer have to concern yourself with magnetizers!
We are all unbelievable idiots so don't feel bad.  
06-05-2013 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,155
Joined on 05-28-2004
Post #: 452
Post ID: 19444
Reply to: 19443
It looks like how it works
fiogf49gjkf0d
The effect indeed is very interesting. I think it has to do with some complex phase interaction what the high knee of ULF squashes the lower knee of midbass. From general perspective I would say that this is not good as I would prefer to observe summation not cancelation. However, this all happens at lower octaves where it very hard to manage anything phase related as the length of the wave is very long. Hypothetically one can run the ULF at a specific phase point. Like cheap subwoofers have a phase dialers that allow selecting any of the 360 degree point. Then we could dial in the exact phase, assuring that we have phase summation at midbass/ULF interaction. There are two problems with this approach. First it is impossible, or very hard to make delays with screwing with sound. At LF it is somehow possible but it is very, very, very hard. Second if we do have the proper midbass/ULF interaction then the midbass have to be build taking this ULF-inspired decay under consideration.  It is practically impossible as to observe the effect possible ONLY after the midbass is build. Looking at the reality of a real life room and some absurd cannels positioning (like midbass in my room) it is unfeasible to predict anything in design stage.

In practical world I think the way how it is done in Macondo is very optimal. The midbass is made as it shell be but the ULF is sitting at transition slope. The fact that it is at transition slope made is very very flexible and it might run at virtually unlimited gain. So, sliding the ULF up and down of the transition slope I in reality modulate the ULF decay, do I do summation or cancelation, I do not really know  if it is summation or cancelation and do not particularly case. This is not how I envisioned it before but it looks like how it works…

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
05-10-2016 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,155
Joined on 05-28-2004
Post #: 453
Post ID: 22611
Reply to: 13597
The end
fiogf49gjkf0d
Well, that is kind of the end of the little midbass era. As we begin to prepare the moving in a month I removed the Vitavox driver from Midbass horns. The even went unnoticed in my family but I have a lot in my hard to feel about. The new house is great, and I am pretty sure that I will be able to get in new listening room a decent Sound but I do not think I will be able even to undertake the project like I did with my midbass horns. I truly believe that no one able to appreciate how elegant it was done in term of room incorporation and how effective it was sound.

"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
05-10-2016 Post does not mapped to Knowledge Tree
mats
Chicago
Posts 85
Joined on 09-18-2005
Post #: 454
Post ID: 22613
Reply to: 22611
Many share
fiogf49gjkf0d
Ah Romy, of course it's a big deal. You did something very special, and shared it with the world. You brought Bruckner into your home, followed you heart, and we all shared a little in the joy. It was truly amazing and inspiring on so many levels. Take it all with you in your heart, to your new home, and play it again for all of us. Well done Cat, very well done. 
12-17-2016 Post does not mapped to Knowledge Tree
Scott L
Posts 17
Joined on 02-26-2008
Post #: 455
Post ID: 22895
Reply to: 22611
A new house --- again
 Romy the Cat wrote:
fiogf49gjkf0dWell, that is kind of the end of the little midbass era. As we begin to prepare the moving in a month I removed the Vitavox driver from Midbass horns. The even went unnoticed in my family but I have a lot in my hard to feel about. The new house is great, and I am pretty sure that I will be able to get in new listening room a decent Sound but I do not think I will be able even to undertake the project like I did with my midbass horns. I truly believe that no one able to appreciate how elegant it was done in term of room incorporation and how effective it was sound.


Sorry Romy, but it has been several months since I have been here. I had only recently been drawn back here because of the topic of the
Infinite baffle bass.

Changing homes again with an elaborate stereo system is no small undertaking. I would not be able to do it.

Best of luck to you and your family !!
04-28-2018 Post does not mapped to Knowledge Tree
vintageman
Posts 2
Joined on 07-17-2014
Post #: 456
Post ID: 24824
Reply to: 14041
Vitavox 15/40
Hi how did your vitavox speaker project go?Im looking for a 1956/57 single original cone 15/40 to complete my vitavox project. Anyone got one?
Page 23 of 23 (456 items) Select Pages:  « First ... « 19 20 21 22 23
   Target    Threads for related reading   Most recent post in related threads   Forum  Replies   Views   Started 
  »  New  45Hz Bass Horn..  Can We Ever be Saved From Ourselves?...  Horn-Loaded Speakers Forum     23  315365  09-19-2006
  »  New  8" Goto Woofer for 60Hz Horn..  It's not a Goto 8in driver...  Horn-Loaded Speakers Forum     5  87437  11-03-2008
  »  New  The Macondo’s Upper Bass Channel: what is next?..  Görlich again...  Horn-Loaded Speakers Forum     30  290633  10-28-2007
  »  New  Jessie Dazzle Project..  Will this better to be auditable?...  Horn-Loaded Speakers Forum     172  1562966  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  2925295  03-28-2010
  »  New  Problems with horns: upper bass ..  Must it be about loading?...  Horn-Loaded Speakers Forum     109  1170572  03-25-2005
  »  New  Midbass Horns and Real Estate...  Just a youtube video......  Horn-Loaded Speakers Forum     247  2144247  07-26-2009
  »  New  Macondo’s lowest channel...  What truly are you tryin to accomplish?...  Horn-Loaded Speakers Forum     150  1397212  09-15-2010
  »  New  Practical Guide for Back Chambers Tuning...  Back chamber’s cost-benefit....  Horn-Loaded Speakers Forum     5  75963  10-21-2006
  »  New  Superbly interesting effect: Suspended decoupled floor ..  Superbly interesting effect: Suspended decoupled floor ...  Playback Listening  Forum     0  18102  10-08-2010
  »  New  Midbass impedance bumps -- why and what to do?..  You need to stop deceive yourself....  Horn-Loaded Speakers Forum     18  194158  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  17284  02-03-2011
  »  New  Impulse response, short notes and midbass horns...  A possible solution to better impulse?...  Horn-Loaded Speakers Forum     14  128276  06-13-2011
  »  New  My new “New” listening room, 2024..  That is not enough efforts in this direction....  Audio Discussions  Forum     31  18110  05-08-2024
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