Or more.
Sure you can measure LF in a room. The near-field (mic close to cone) can give a reasonable response of the woofer anechoic response. If the mic comes out further you are measuring the speaker and the room. To properly measure this you need to map the reponse with a 3D map with many measures.
dave
The long waves bouncing around the room interfering causing peaks or nulls at anyone point, how accurately can you measure the level at any one frequency? The level can also rise due to room gain although you may not hear it as perception reduces.
If you have good kit, you can measure what it is at a spot… x,y,z and freq (so a 4D matrix, not a 3D one).
Put the xyz on a 3D countour plot with a slider for frequency. The chart needs to be rotatable so it can be looked at a number of ways.
As you slide the freq down from about 300 Hz or so you should start to see the standing waves pile up as the wavelengths get longer.
Then you want to 1st use placment, then EQ with the multiple subs to try to minimize the hills and maximize the dales. For bass from the mains you have a little bit less control placement wize (they still have to be where midTop works), but EQ might help.
I imagine a DSP where you can do that in the bass with subs, but have the mains just go down naturally, and have the Subs dialed in to fill their ripples. That idea might be patentable except that i have said it here.
From what Toole says, Harmon have a software tool (proprietary) for modeling the woofer placement, adding real world measures and outputting suggestions for level, phase, & EQ for setting each woofer. I am sure there are also lots of suggestions in Geddes multiple woofers thread.
dave
Put the xyz on a 3D countour plot with a slider for frequency. The chart needs to be rotatable so it can be looked at a number of ways.
As you slide the freq down from about 300 Hz or so you should start to see the standing waves pile up as the wavelengths get longer.
Then you want to 1st use placment, then EQ with the multiple subs to try to minimize the hills and maximize the dales. For bass from the mains you have a little bit less control placement wize (they still have to be where midTop works), but EQ might help.
I imagine a DSP where you can do that in the bass with subs, but have the mains just go down naturally, and have the Subs dialed in to fill their ripples. That idea might be patentable except that i have said it here.
From what Toole says, Harmon have a software tool (proprietary) for modeling the woofer placement, adding real world measures and outputting suggestions for level, phase, & EQ for setting each woofer. I am sure there are also lots of suggestions in Geddes multiple woofers thread.
dave
Are you saying that a Faraday cage would not block the transmission of a wireless mic placed inside the cage?
Sorry but you are applying the wrong concepts or parameters here.
Faraday cages stop *electromagnetic* waves, period.
Frequency is not an issue; a Faraday cage will happily block what we call "radio waves" , going up to light frequencies (and higher) and down to mains line ones (which sit solidly in the low Audio Frequency range) and lower, down to and including DC (zero Frequency) , as long as all are electromagnetic.
The "Audio" frequencies you claim are not affected are Mechanical/Acoustic, absolutely unrelated.
So....faraday will block out low audio frequency range then, including zero? As all as they're all electromagnetic??
But audio frequencies are not affected, like acoustic are not affected??
Does that mean if I wrap my...radio within an faraday it will stop things signals in and out?
I thankyou others for recommendations but what microphones would captive acoustic the best? Despite other noises being around - like low frequencies?
But audio frequencies are not affected, like acoustic are not affected??
Does that mean if I wrap my...radio within an faraday it will stop things signals in and out?
I thankyou others for recommendations but what microphones would captive acoustic the best? Despite other noises being around - like low frequencies?
I have this situation but it's an long story...and i'll keep it belief....
My daughter has parabolic microphone sound amplifier and monocular will enable you hear sounds up to 300 feet away. She brought it some 2 years ago for bird watching - quite an natural lover that one. But recently she tried to use it on the neighbor's to see if it would help...well...all she caught was clear radio music but when she attempted to record it as an test. It didn't even show??? Could someone please explain this?
My daughter has parabolic microphone sound amplifier and monocular will enable you hear sounds up to 300 feet away. She brought it some 2 years ago for bird watching - quite an natural lover that one. But recently she tried to use it on the neighbor's to see if it would help...well...all she caught was clear radio music but when she attempted to record it as an test. It didn't even show??? Could someone please explain this?
Try wrapping your portable AM radio in aluminium foil to see if that stops the radio signals from reaching the set's internal AM aerial.
Sound would be able to escape out through the foil, but there won't be any sound produced if the Faraday cage is effective at blocking the incoming radio signal.
Sure, if you want to be pedantic about it. The concept I was tying to apply here was humor. Apparently it missed the mark for the literal minded.
The only way to stop a mic gathering sound in a Faraday cage would be if that mic was using RF to transmit to a receiver outside the cage. Meant in jest. The joke is dead if you have to explain it.
From what I'm told, just from inside our house and everything was quiet here apparently.
Seems like a recording problem to me. If she "caught" it can we assume she heard it on earphones? How did she attempt to record that signal? Is the recorder built into the parabolic mic rig, or is it an external device?
Perhaps the neighbours have found a way to jam your daughter's surveillance system!
The microphone was inbuilt into the parabolic mic rig, she heard it but couldnt capture it. There is a little more to it but am i able to message you privately instead by any chance? Im seeking for as much advice as possible.
Perhaps the neighbours have found a way to jam your daughter's surveillance system!
Thankyou for the humour but unfortunately i was hoping for a more serious reply.
Anything you can hear through earphones can be recorded.
Earphones are electromechanical transducers which are driven by a combination of voltage and current (a.k.a. "power").
You can tap that voltage and direct it to a recording device, to a scope to see waveform, to an analyzer, to a preamp and send it milesaway, to a radio transmitter, whatever.
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