restorer-john
Grand Contributor
Shall I ring my mates at ASIO/ASD- they've got a nice one in the Ben Chifley building basement in Canberra?
https://www.abc.net.au/news/2020-08-21/inside-asio-secure-building-chamber-of-secrets/12577352
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March Audio Sointuva Speaker
- Thread starter March Audio
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Shall I ring my mates at ASIO/ASD- they've got a nice one in the Ben Chifley building basement in Canberra?
https://www.abc.net.au/news/2020-08-21/inside-asio-secure-building-chamber-of-secrets/12577352
OP
- Thread Starter
- #242
Be great if we could travel - damn covid!Shall I ring my mates at ASIO/ASD- they've got a nice one in the Ben Chifley building basement in Canberra?
View attachment 95905
https://www.abc.net.au/news/2020-08-21/inside-asio-secure-building-chamber-of-secrets/12577352
The outdoor measurements we are conducting are actually very good. 8m off the ground is enough to make the low frequency perturbations insignificant.
Can you post pictures of this kind of measurement? I am curious to know how you are practically doing...it should be a spectacular installation..Be great if we could travel - damn covid!
The outdoor measurements we are conducting are actually very good. 8m off the ground is enough to make the low frequency perturbations insignificant.
restorer-john
Grand Contributor
Hmmmm was a long time ago (97), but I remember walking into a room on steel walk way, and my mate spoke to me back to back and I could not hear sound. I will Google RF chamber, not sure what that is.
I also remember seeing a coffin-like anechoic box on rollers on YouTube, perhaps you could fab that for cheap?
Just spitballin
OP
- Thread Starter
- #247
Rf chamber is exactly the same thing but for testing radio frequency items.
I did have a small insight into Curtins RF work a few years ago for the antenna (amps) for the square km array as I worked representing Keysight products (spectrum analysers etc).
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OP
- Thread Starter
- #248
You have no idea how close that is to the truth with some testing I have performed in the past
Currently using a scissor lift to get the microphone, horizontal boom and speaker turntable off the ground.
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amazing! I am really eager to see a real picture. However the one of restorer-john is a great introduction to the concept!You have no idea how close that is to the truth with some testing I have performed in the past
Currently using a scissor lift.
AndrewDavis
Active Member
Alan, your speaker’s backside looks better than most other speaker’s front!!
OP
- Thread Starter
- #252
Here you go, this is it. Gave the crossover a good talking to. As I suspected the 3kHz dip was not just diffraction. Now resolved.
Measured at 2m corrected. Revised sensitivity is 85dB/2.83v/m (pink noise 500Hz to 2000Hz)
Measured at 2m corrected. Revised sensitivity is 85dB/2.83v/m (pink noise 500Hz to 2000Hz)
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That is some good, wide directivity, DI stays about <=5 until 5kHz.
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OP
- Thread Starter
- #254
OP
- Thread Starter
- #255
On axis frequency response stays about +- 1.5dB 50Hz to 20kHz
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OP
- Thread Starter
- #256
Impedance
OP
- Thread Starter
- #257
Low frequency response
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Looking good! Is this your first speaker design ever @March Audio ?
OP
- Thread Starter
- #259
No, I have designed a 3 way active DSP floorstander previously plus a very small passive bookshelf, but that was for my own use. This is the first commercial one.
OP
- Thread Starter
- #260
Distortion
Brown Fundamental
Black THD H2, H3
Red H2
Orange H3
Prototype has rattle at 350Hz. Will be fixed in production.
2.83 v (85dB)
96dB
Brown Fundamental
Black THD H2, H3
Red H2
Orange H3
Prototype has rattle at 350Hz. Will be fixed in production.
2.83 v (85dB)
96dB
- Status
