Hi Graham,
If I understand correctly your circuit allows the woofer to control itself more instead of being controlled by the amplifier, in other words, it just kills a bit of the high dampening factor of the amplifier.
Hmmm, interesting. I have noiced with my Phy-Hp midranges that they don not like to be controlled too much by the amplifier. Their surround and spider are stiff enough to give them enough control on their own. In case of the Phy-Hp or any other similar wide-range stiff surround unit I think this has to do with the flexing of the cone itself. It's simply not possible to start/stop the whole cone just by controlling the force on the voicecoil. If you brutely stop the voicecoil the rest of the cone can shoot trough wich can result in a shrill sounding higher midrange.
In case of your woofers this seems less of the issue because they have a much stiffer cone, maybe I'm wrong here.
Are the values in your circuit much dependant on the woofers/baffle used ? Would like to try it out, see if I have some suitable transformers left somewhere in my junkbox.
I'm using two vintage JBL2205 Alnico's per side in a W-frame powered by a UCD700HG and no matter how much eq I apply they will not go any lower than 35 to 40Hz in my room, so I guess your circuit will not be able to get them any lower.
If I understand correctly your circuit allows the woofer to control itself more instead of being controlled by the amplifier, in other words, it just kills a bit of the high dampening factor of the amplifier.
Hmmm, interesting. I have noiced with my Phy-Hp midranges that they don not like to be controlled too much by the amplifier. Their surround and spider are stiff enough to give them enough control on their own. In case of the Phy-Hp or any other similar wide-range stiff surround unit I think this has to do with the flexing of the cone itself. It's simply not possible to start/stop the whole cone just by controlling the force on the voicecoil. If you brutely stop the voicecoil the rest of the cone can shoot trough wich can result in a shrill sounding higher midrange.
In case of your woofers this seems less of the issue because they have a much stiffer cone, maybe I'm wrong here.
Are the values in your circuit much dependant on the woofers/baffle used ? Would like to try it out, see if I have some suitable transformers left somewhere in my junkbox.
I'm using two vintage JBL2205 Alnico's per side in a W-frame powered by a UCD700HG and no matter how much eq I apply they will not go any lower than 35 to 40Hz in my room, so I guess your circuit will not be able to get them any lower.
>>If I understand correctly your circuit allows the woofer to control itself more instead of being controlled by the amplifier, in other words, it just kills a bit of the high dampening factor of the amplifier. <<
Yes. Which also increases the Qes of the driver, but not at all frequencies, hence there is control and some cut above Fs when compared to the direct connection.
>>Hmmm, interesting. I have noiced with my Phy-Hp midranges that they don not like to be controlled too much by the amplifier. It's simply not possible to start/stop the whole cone just by controlling the force on the voicecoil. If you brutely stop the voicecoil the rest of the cone can shoot trough which can result in a shrill sounding higher midrange.<<
Yes. With direct SS amplifier connection there is a closed circuit reaction in series with voice coil impedance.
>>Are the values in your circuit much dependant on the woofers/baffle used ? <<
Very much so. Woofer+baffle+position+room.
>>I'm using two vintage JBL2205 Alnico's per side in a W-frame<<
Lucky guy!
>>powered by a UCD700HG and no matter how much eq I apply they will not go any lower than 35 to 40Hz in my room<<
Part of the point I am making.
>>so I guess your circuit will not be able to get them any lower.<<
It WILL !
That boost at and just below Fs is with raised impedance, so the amplifier is not 'damping the cone as soon as it gets moving' so to speak.
Just any old junk will test this. Then refine, and then order.
I'm wondering about transformers here. Whether to buy or wind my own.
Couple of options are these, but don't know where available or prices.
http://www.dls.se/econtent/files/63/brxzm1e.pdf
http://www.lundahl.se/pdfs/datash/2418.pdf
(Also try numbers 2410 and 2414 in last address.)
For interest my original circuit was;-
Cheers ......... Graham.
Yes. Which also increases the Qes of the driver, but not at all frequencies, hence there is control and some cut above Fs when compared to the direct connection.
>>Hmmm, interesting. I have noiced with my Phy-Hp midranges that they don not like to be controlled too much by the amplifier. It's simply not possible to start/stop the whole cone just by controlling the force on the voicecoil. If you brutely stop the voicecoil the rest of the cone can shoot trough which can result in a shrill sounding higher midrange.<<
Yes. With direct SS amplifier connection there is a closed circuit reaction in series with voice coil impedance.
>>Are the values in your circuit much dependant on the woofers/baffle used ? <<
Very much so. Woofer+baffle+position+room.
>>I'm using two vintage JBL2205 Alnico's per side in a W-frame<<
Lucky guy!
>>powered by a UCD700HG and no matter how much eq I apply they will not go any lower than 35 to 40Hz in my room<<
Part of the point I am making.
>>so I guess your circuit will not be able to get them any lower.<<
It WILL !
That boost at and just below Fs is with raised impedance, so the amplifier is not 'damping the cone as soon as it gets moving' so to speak.
Just any old junk will test this. Then refine, and then order.
I'm wondering about transformers here. Whether to buy or wind my own.
Couple of options are these, but don't know where available or prices.
http://www.dls.se/econtent/files/63/brxzm1e.pdf
http://www.lundahl.se/pdfs/datash/2418.pdf
(Also try numbers 2410 and 2414 in last address.)
For interest my original circuit was;-
Cheers ......... Graham.
Attachments
Maybe you should start a new thread on this subject, it's surely interesting enough. Are there any clues how to figure out the right values by impedance measuring for example. It seems like the circuit puts a high demand on the amplifier used, not a problem in my case but I think a mediocere plate amp wich many people tend to use could run out of steam very easily.
I've got some big 100V line transformers with a 70V and a 100V tap. I have used these before as a autoformer (primary left unconnected) by connecting the amp to the 70V tap and the speaker to the 100V tap. Worked out pretty well as impedance matching for he 16Ohms Phy-Hp to the 8Ohm output transformer of my amp. Maybe thes could be used for the woofer experiment as well. These will only give a 3dB boost then offcoarse.
I've got some big 100V line transformers with a 70V and a 100V tap. I have used these before as a autoformer (primary left unconnected) by connecting the amp to the 70V tap and the speaker to the 100V tap. Worked out pretty well as impedance matching for he 16Ohms Phy-Hp to the 8Ohm output transformer of my amp. Maybe thes could be used for the woofer experiment as well. These will only give a 3dB boost then offcoarse.
Hi Sjef,
Yes a new thread would be possible, but I would so love Magnetar to gives this a try.
The new 'Stargate' baffle looks superb, and his 21" with this circuit could be just the (HT) OB ticket.
I'm not in a position to cover all the tuning aspects at the moment, but the 'ear' soon decides which values are best.
Those shown are merely starting points.
The reason for this comment being that a measured SPL/frequency response cannot tell the full story.
Also mentioned here.
http://www.audiocircle.com/circles/...?topic=53322.20
Cheers ....... Graham.
Yes a new thread would be possible, but I would so love Magnetar to gives this a try.
The new 'Stargate' baffle looks superb, and his 21" with this circuit could be just the (HT) OB ticket.
I'm not in a position to cover all the tuning aspects at the moment, but the 'ear' soon decides which values are best.
Those shown are merely starting points.
The reason for this comment being that a measured SPL/frequency response cannot tell the full story.
Also mentioned here.
http://www.audiocircle.com/circles/...?topic=53322.20
Cheers ....... Graham.
Great OB!
Congratulations Magnetar!
Would you give guidelines forthose who wouldliketo build similar OB for themselves?
How about a smaller room modifications?
I like your half cones/half drivers approach. Semms to me that the audio range is too wide to be covered by one type of speaker. (Maybe even amp.)
Hope you will be happy with your speakers fora very long time!
Congratulations Magnetar!
Would you give guidelines forthose who wouldliketo build similar OB for themselves?
How about a smaller room modifications?
I like your half cones/half drivers approach. Semms to me that the audio range is too wide to be covered by one type of speaker. (Maybe even amp.)
Hope you will be happy with your speakers fora very long time!
Re: Great OB!
These work fine in a smaller room. They are in fact gone, someone had to have them. They have a smaller room to flex their muscles in.
The idea is to to make one coherent wave front that interacts pleasantly with your room, emotions and senses. Low compression, distortion and dipole radiation helped in this case. This speaker was more empirical then anything else after building loudspeakers for thirty years.
My next compromise is on the drawing board and will be quite different. No horns or waveguides this time.
hakunin said:
These work fine in a smaller room. They are in fact gone, someone had to have them. They have a smaller room to flex their muscles in.
The idea is to to make one coherent wave front that interacts pleasantly with your room, emotions and senses. Low compression, distortion and dipole radiation helped in this case. This speaker was more empirical then anything else after building loudspeakers for thirty years.
My next compromise is on the drawing board and will be quite different. No horns or waveguides this time.
Magnetar said:
Magnetar,
I am curious as to your experience with the Pyle PDW21250 21"...
Have you run any frequency response curves or do you know of any that have been published?
I'm particularly curious as to it's behavior up to 500 Hz and beyond.
Also, do you know what the moving mass and X-max values are for the device.
Thank you ahead of time for any answers you might provide.
Your system looks like a load of fun...Enjoy!
- Jim Croft
JamesCroft said:
I would not use them above 200 hz, they have a rising response to about 1K and a peak around 1.7K that is bad but well down is crossed over below 200 cycles with a 4th order electronic crossover. In this system they filled in below the 12. I don't know the xmax but can say when high passed at 50 cycles (3rd order) with a 275 WPC power they did not strain one bit. Now they are used down to 30 cycles with no sub and are OK. I never like to run my bass without a high pass filter, for sure if it's an open baffle. It's 'stupid'...
BHTX said:Welcome back Magnetar.
No horns or waveguides?
Sounds interesting! Any clues? Pleeease??
I finally have gathered up enough RTR electrostatic drivers to make a floor to ceiling dipole line source. They still remain to be the most satisfying, transparent transducer I have ever heard. They will go down to 1200 with little compromise (a single is good 1500 to 35000 cycles with rising response) in the line. Below that (next to them!) will be a line of 5.25" concave single piece aluminum drivers (92 db/watt each) then a line of 10's all open back. With all the warts of a line array they still do somethings special that appeal to me. Mainly in the way they drive my room.
Hi Freddy,
Seems Magnetar was banned.
We don't know what happened behind the scenes.
http://www.diyaudio.com/forums/show...029#post1562029
Maybe Magnetar was provoked or treated inappropriately.
I started a thread about it but that was closed too.
( Moderators Rule ! And in this case NOT respected by me.
Something isn't right here ! )
Cheers ...... Graham.
Seems Magnetar was banned.
We don't know what happened behind the scenes.
http://www.diyaudio.com/forums/show...029#post1562029
Maybe Magnetar was provoked or treated inappropriately.
I started a thread about it but that was closed too.
( Moderators Rule ! And in this case NOT respected by me.
Something isn't right here ! )
Cheers ...... Graham.
Star Date now RTR is vertical and rising...
Freddy: as you suggested the keeper of the stargate need only position the portal at another location perhaps near the constellation of Pumma. I too enjoy the the work of the gate Meister. Post on Magnetar the Universe is infinite. Regards Moray James.
Freddy: as you suggested the keeper of the stargate need only position the portal at another location perhaps near the constellation of Pumma. I too enjoy the the work of the gate Meister. Post on Magnetar the Universe is infinite. Regards Moray James.
regarding use of 21" 30hz Q~1 speakers on a board - I tried x21 but not as refined or braced as Magnetar's setups so mine had some muddiness
X21 Madison on 2'x4' baffle halfspace with and without generic LC "boost" aka ampkiller
a high source Z precludes this LC "boost" from working
sensitivity of the 21" woofer is low in the upper bass region - here it is (with no network) versus an old Karlson 12 type box tuned to ~53Hz and a LC network which presents a brutal load for some amps and caused one of my Samson amps to go into a ratcheting mode at relatively low levels - the little Karlson was awfull punchy for something which is not supposed to "work"
X21 Madison on 2'x4' baffle halfspace with and without generic LC "boost" aka ampkiller
An externally hosted image should be here but it was not working when we last tested it.
a high source Z precludes this LC "boost" from working
An externally hosted image should be here but it was not working when we last tested it.
sensitivity of the 21" woofer is low in the upper bass region - here it is (with no network) versus an old Karlson 12 type box tuned to ~53Hz and a LC network which presents a brutal load for some amps and caused one of my Samson amps to go into a ratcheting mode at relatively low levels - the little Karlson was awfull punchy for something which is not supposed to "work"
An externally hosted image should be here but it was not working when we last tested it.
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