Airborne Dinner
Not easy to add a birdbath in my current condition, although we had one in Silverdale, Washington and it provided endless entertainment. I console myself the birds can cool off in the nearby stream any time they want - they also seem pretty well adapted to the heat, which is part of the high-prairie climate where we live. (Colorado is both hot and cold, unlike the Northern European weather of the Pacific Northwest.) Maybe later this summer, or next spring.
This is the first time since winter I've used the new Pentax K10D, so here's a 1:1 crop of a 10Mpixel full-frame shot. Sharpness could be better, since shooting through a double-pane plate-glass window isn't ideal, and the DA 50~200mm zoom is not at its sharpest at full aperture. I like the Pentax color, though - it's pretty close to what the birds really look like.
Yes, that's the mother on the left - as attentive as ever, even though the baby birds left the nest two days ago.
Not easy to add a birdbath in my current condition, although we had one in Silverdale, Washington and it provided endless entertainment. I console myself the birds can cool off in the nearby stream any time they want - they also seem pretty well adapted to the heat, which is part of the high-prairie climate where we live. (Colorado is both hot and cold, unlike the Northern European weather of the Pacific Northwest.) Maybe later this summer, or next spring.
This is the first time since winter I've used the new Pentax K10D, so here's a 1:1 crop of a 10Mpixel full-frame shot. Sharpness could be better, since shooting through a double-pane plate-glass window isn't ideal, and the DA 50~200mm zoom is not at its sharpest at full aperture. I like the Pentax color, though - it's pretty close to what the birds really look like.
Yes, that's the mother on the left - as attentive as ever, even though the baby birds left the nest two days ago.
Attachments
Nice pic Lynn,
In my own LS tests I have become quite fed up of the 'sound' changing with level due to our human hearing characteristics.
I have come up with this little subcircuit, which is my first attempt, and thus the values need to be refined to better equalise the Fletcher-Munson curves.
Needs low impedance source and >10k amplifier.
Volume control circuit here.
Characteristics in my next post.
There are bound to be other versions out there but this one remains simple with 5k lin pots, and has a smooth onset of loudness compensation.
Cheers .......... Graham.
In my own LS tests I have become quite fed up of the 'sound' changing with level due to our human hearing characteristics.
I have come up with this little subcircuit, which is my first attempt, and thus the values need to be refined to better equalise the Fletcher-Munson curves.
Needs low impedance source and >10k amplifier.
Volume control circuit here.
Characteristics in my next post.
There are bound to be other versions out there but this one remains simple with 5k lin pots, and has a smooth onset of loudness compensation.
Cheers .......... Graham.
Attachments
The Silver Iris Augie looks like a lot of fun:
Would work with a lot of the ideas here and for those people that don't require the huge output Lynn wants..
http://www.blackdahlia.com/html/tip_59.html
Also the link reminds us to be careful when comparing driver efficiencies
Would work with a lot of the ideas here and for those people that don't require the huge output Lynn wants..
http://www.blackdahlia.com/html/tip_59.html
Also the link reminds us to be careful when comparing driver efficiencies
VVLOB / Virtual Very Large Open Baffle
Hi
Following the idea of Virtual-Very-Large-Open-Baffles, even better optimisation can be found when placing the speaker on edge somwhere in the middle of the baffle.
The simulation ( sorry, still EDGE with slightly imprecise values until receiving A,B,C Dipole
) again shows a FR comparison for a 360 mm x 400 mm OB ( violet ) respectively a baffle of a closed box ( green ) – and a OB 100 times this size ( red )
All that is needed would be two planks from floor to ceiling and some sealing to the wall.
Much less ugly looking than the TANGRAM before, eh ?
NO dipole operation though.
Greetings
Michael
Hi
Following the idea of Virtual-Very-Large-Open-Baffles, even better optimisation can be found when placing the speaker on edge somwhere in the middle of the baffle.
An externally hosted image should be here but it was not working when we last tested it.
The simulation ( sorry, still EDGE with slightly imprecise values until receiving A,B,C Dipole
) again shows a FR comparison for a 360 mm x 400 mm OB ( violet ) respectively a baffle of a closed box ( green ) – and a OB 100 times this size ( red )An externally hosted image should be here but it was not working when we last tested it.
All that is needed would be two planks from floor to ceiling and some sealing to the wall.
Much less ugly looking than the TANGRAM before, eh ?
NO dipole operation though.
Greetings
Michael
The number of posts per page can be set in user preferences. If you delete your cookie, your preferences will revert to default.
1600 posts over 32 pages is 50 per page. While I haven't looked through the whole thread, my guess is that no posts have been removed...
Maybe the default changed?
Herm
1600 posts over 32 pages is 50 per page. While I haven't looked through the whole thread, my guess is that no posts have been removed...
Maybe the default changed?
Herm
Variac said:
Olsher says in that link: ''Some of you may have noticed by now the discrepancy in sensitivity between the Augie woofer and the D5nf (89dB versus about 97dB) and must be wondering how is it possible to match these drivers without padding down the Feastrex full range? The answer lies partly in the subtlety inherent in the definition of sensitivity, which is not referenced to an actual watt at 1 meter, but rather to 2.83 V across the terminals of the loudspeaker. For an 8-Ohm load, that translates into 1 watt of power sunk into the load. However, in the OB2's driver transition region, the Augie's impedance is about 6 Ohms while that of the D5nf is 16 Ohms. For 2.83 V across the OB2's input terminals, the Augie is dissipating 1.33 watts to the D5nf's 0.5 watts. The power ratio amounts to about 8.5dB and means that the Augie is working that much harder to keep up with the D5nf. Add 8.5dB to the Augie's nominal sensitivity and you end up with 97.5dB. The proof is in the measured frequency response, which is shown below.''
But speakers are voltage controlled and not power controlled devices
He probably drives from a 16 ohm tap also?
Here is a pic of what I am brewing up with people who can cut more inches of wood than fingers, repeatedly. This is the "Does it all fit?" solid model. Next I try and strangle some flat panel measurements from it, one's that someone else can read.
Then, sawdust.
Bud
Then, sawdust.
Bud
Attachments
Re: VVLOB / Virtual Very Large Open Baffle
Michael... I think that up against the wall speakers will be more in demand than dipoles.
Flat Panel Displays mounted onto the wall are becoming the main architectural feature in most homes. Getting great sound from up against the wall speakers could make one rich and famous.
mige0 said:
Michael... I think that up against the wall speakers will be more in demand than dipoles.
Flat Panel Displays mounted onto the wall are becoming the main architectural feature in most homes. Getting great sound from up against the wall speakers could make one rich and famous.