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Joined 2009
you can maybe use a hammock for a listening chair but that begins to border suspension insanity
Its still a prototype, but looking better than ever!
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
All we need now is some swingin' music!
Lionel Hampton !!!
An externally hosted image should be here but it was not working when we last tested it.
Look here :
http://www.jazzprofessional.com/memorial/Lionel Hampton VOA.htm
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The latest update was cloth grilles for the main dipoles. I made a frame from 15x15mm lumber, and just stabled the cloth on the rear side. Looks nice from the front at least....
An externally hosted image should be here but it was not working when we last tested it.
Great work, Stig!
I am curious. Will you tell us more about the wall treatment/s hidden behind the drapes on the left and right and behind the main speakers? What have you placed where, why, and their resulting effects?
Thanks again for the great pictures and for providing an incentive to an amateur such as myself to experiment with something similar.
I am curious. Will you tell us more about the wall treatment/s hidden behind the drapes on the left and right and behind the main speakers? What have you placed where, why, and their resulting effects?
Thanks again for the great pictures and for providing an incentive to an amateur such as myself to experiment with something similar.
The room is build as a LEDE room - Live End Dead End, mening that one end of the room is "live" (reflective / diffused) and the other "dead" (non-reflective).
The walls are covered with absorbers - approx 15 cm of Rockwool with a 3 cm Rockwool ceciling tile on top to keep the Rockwool dust from entering the room. In each corner there's a corner trap, made from ceiling tiles placed at 45 degrees in the corner, and the room behind is filled with Rockwool. Thickness is 1 meter in the middle. I have the same treatment in the ceciling, but not covering the entire surface. The front end of the room is more or less reflection-free down to 200 Hz. The corner traps are effective to approx 50 Hz.
The walls are covered with absorbers - approx 15 cm of Rockwool with a 3 cm Rockwool ceciling tile on top to keep the Rockwool dust from entering the room. In each corner there's a corner trap, made from ceiling tiles placed at 45 degrees in the corner, and the room behind is filled with Rockwool. Thickness is 1 meter in the middle. I have the same treatment in the ceciling, but not covering the entire surface. The front end of the room is more or less reflection-free down to 200 Hz. The corner traps are effective to approx 50 Hz.
With those black cubes and widely lit ceiling your room now reminds me of early Cray and IBM supercomputer installations - celebrated with the same aura of mystery and "dark force". I'm only missing a console with blinking lights - and the door through which Darth V. would enter the room.
I know of people who believe that your room treatment had become necessary with the introduction of your dipoles. Looking at the first pictures in this thread (when it all started) I already can see a black curtain.
Could you clarify, if - and if "yes" - what parts of your room treatment have been added in context with these dipoles?
Thanks, Rudolf
I know of people who believe that your room treatment had become necessary with the introduction of your dipoles. Looking at the first pictures in this thread (when it all started) I already can see a black curtain.
Could you clarify, if - and if "yes" - what parts of your room treatment have been added in context with these dipoles?
Thanks, Rudolf
The room was built 13 years ago, and nothing has changed since then, except for the black drapes. They are just cosmetic anyway... The dipoles have not required any changes to the room.
The black speakers and drapes, and no visible LED's or any equipment is because I like to listen in complete darkness. It shuts out the eyes, which is the dominant of our senses.
I know may people like to hear the dipole rear wave reflected off the front wall. I'm not one of them... or else I could have taken some of the absorbtion away.
The black speakers and drapes, and no visible LED's or any equipment is because I like to listen in complete darkness. It shuts out the eyes, which is the dominant of our senses.
I know may people like to hear the dipole rear wave reflected off the front wall. I'm not one of them... or else I could have taken some of the absorbtion away.
Yes, I am familiar with the LEDE concept. Last Fall I implemented my first humble foray into open baffle (at least for the mids). Immediately, I went to work to change the reflective values of parts of my room which helped this OB system really come alive and image very well. Not too many these days seem to remember LEDE.
I am anxiously looking forward to putting up a "nude" system using (per channel) 4 Audax HP210Z2, 2 Audax HM130ZO, and the venerable Seas 27TDC tweeter. It will be embellished by a stereo pair of 15" subs, 2 ALESIS M-EQ230 equalizers, a Dalquist LP-1 low pass filter, and a pair of highly modded amps. It will be a very modest attempt to appreciate nudeness, but that's what this hobby is all about.
.I am anxiously looking forward to putting up a "nude" system using (per channel) 4 Audax HP210Z2, 2 Audax HM130ZO, and the venerable Seas 27TDC tweeter. It will be embellished by a stereo pair of 15" subs, 2 ALESIS M-EQ230 equalizers, a Dalquist LP-1 low pass filter, and a pair of highly modded amps. It will be a very modest attempt to appreciate nudeness, but that's what this hobby is all about.
I've heard the same dipole speakers* in both my LEDE room and a non-treated room, where they are quite close to the front wall also. The imaging is more accurate in the dead room, and everything sounds a bit bigger in the live room, but you do loose the finer details. To put it simple: In the dead room you are transported into the recording, in the live room you have the recording in your room. I'm not saying that either one is bad or incorrect, its more a matter of preference.
* : http://www.diyaudio.com/forums/mult...kwitz-presentation-dipole-speaker-system.html
* : http://www.diyaudio.com/forums/mult...kwitz-presentation-dipole-speaker-system.html
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Lately I've been listening to different XO points between the 8" woofers and the 21" H-baffle subwoofers - 80, 100 and 120 Hz. I've been very careful to ensure that the three different XO's resulted in exactly the same frequency response, or else I would be comparing different frequency responses instead of XO points.
I like the 120 Hz XO best. Compared to 80 Hz, the cone movement of the 8" woofers is dramatically reduced. Sonically, the bass and lower midrange is cleaner, especially noticable on piano and acoustic bass.
I like the 120 Hz XO best. Compared to 80 Hz, the cone movement of the 8" woofers is dramatically reduced. Sonically, the bass and lower midrange is cleaner, especially noticable on piano and acoustic bass.
Time for a little update!
I've moved back to 100 Hz XO between the subs and 8" woofers. There was "something" happening around 120 Hz in those giant H-baffles.... anyway, its gone with 100 Hz XO.
If you take a look at this drawing, you'll see that the side sub's are quite close to the walls:
Not a good idea, so I moved all subs approx 30 cm closer to the listeing position. Now the sub's are breathing much better, and the bass is cleaner. Only problem is that the two center subs are very close to the listening position, I can almost touch them with my feet when sitting in the listening chair....
Next thing up is to tune the room a little more. Updates will follow!
I've moved back to 100 Hz XO between the subs and 8" woofers. There was "something" happening around 120 Hz in those giant H-baffles.... anyway, its gone with 100 Hz XO.
If you take a look at this drawing, you'll see that the side sub's are quite close to the walls:
An externally hosted image should be here but it was not working when we last tested it.
Not a good idea, so I moved all subs approx 30 cm closer to the listeing position. Now the sub's are breathing much better, and the bass is cleaner. Only problem is that the two center subs are very close to the listening position, I can almost touch them with my feet when sitting in the listening chair....
Next thing up is to tune the room a little more. Updates will follow!
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Hi,
it seems to me that you are pretty close to where you want to go with this project. A couple of months ago everything was in flux and it has been a lot of fun to watch you play. How about something more exciting? Have you considered adding servo-feedback to your subs? A friend of mine has had great success with this for a closed box sub. I believe that the improvement would be even greater for an open baffle sub given that the excursion is often greater for an OB. You will need to beware of the dipole resonance of course(could be a show-stopper?).
Here is a link to the servo-sub built by my friend (in norwegian, sorry...):
Servobass. +- 1 dB fra 12 til 100 Hz
He got a reduction in total harmonic distortion as follows:
23Hz 26.4% => 4.76%
35Hz 8.4% => 1.32%
47Hz 5.33% => 0.94%
59Hz 4.06% => 0.85%
70Hz 3.25% => 1.09%
The subwoofer had 2x10" XLS elements in a 63ltr box. The drive level was 30Vrms for the measurements I mentioned above. I have unfortunately not listened to the sub, but the measurements speak for themself. I keep wondering why there is so little interest in building servo-subs.
regards,
Øyvin
it seems to me that you are pretty close to where you want to go with this project. A couple of months ago everything was in flux and it has been a lot of fun to watch you play. How about something more exciting? Have you considered adding servo-feedback to your subs? A friend of mine has had great success with this for a closed box sub. I believe that the improvement would be even greater for an open baffle sub given that the excursion is often greater for an OB. You will need to beware of the dipole resonance of course(could be a show-stopper?).
Here is a link to the servo-sub built by my friend (in norwegian, sorry...):
Servobass. +- 1 dB fra 12 til 100 Hz
He got a reduction in total harmonic distortion as follows:
23Hz 26.4% => 4.76%
35Hz 8.4% => 1.32%
47Hz 5.33% => 0.94%
59Hz 4.06% => 0.85%
70Hz 3.25% => 1.09%
The subwoofer had 2x10" XLS elements in a 63ltr box. The drive level was 30Vrms for the measurements I mentioned above. I have unfortunately not listened to the sub, but the measurements speak for themself. I keep wondering why there is so little interest in building servo-subs.
regards,
Øyvin
I guess there's little interest in servo feedback because of the complexity of it all, and such systems are a bit tricky to tune and get stable as I understand?
When playing "loud" I rarely go above 1 W to each 21" woofer, thus the cone excursion remain low, and THD should be low as well. I have not measured THD, but that would be rather quick to do with my CLIO. Will look into it.
I've also mounted the drivers in opposing directions, which do reduce 3rd harmonic a lot.
When playing "loud" I rarely go above 1 W to each 21" woofer, thus the cone excursion remain low, and THD should be low as well. I have not measured THD, but that would be rather quick to do with my CLIO. Will look into it.
I've also mounted the drivers in opposing directions, which do reduce 3rd harmonic a lot.
Here's a couple of THD measurements on one of the H-baffle subs. At 1 meter they produce quite an SPL as you can see - 100 dB at 40 Hz, and close to 90 dB at 20 Hz with 1 W input. Even when playing loud, I rarely go above 1 W to each sub.
Both 2nd and 3rd is around 1%.
At 0.1 W its more or less the same.
At 10 W cone excursion starts to get substatial, and THD is rising at low frequencies, as expected. Still not bad - around 3% at 20 Hz. Also note that the SPL is close to 100 dB at 20 Hz.
An externally hosted image should be here but it was not working when we last tested it.
Both 2nd and 3rd is around 1%.
At 0.1 W its more or less the same.
At 10 W cone excursion starts to get substatial, and THD is rising at low frequencies, as expected. Still not bad - around 3% at 20 Hz. Also note that the SPL is close to 100 dB at 20 Hz.
An externally hosted image should be here but it was not working when we last tested it.
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Looks like you have the perfect set up for listening to Blumlein recordings, with the 90º included angle between the main speakers.
Do you have any/many pure Blumlein recordings? I could send you a couple of mine if you send me your address by PM.