Hi at all,
I have a question.
When measuring the farfield frequency response of a 12'' woofer (3 way speaker), placing the mic at an adequate distance from baffle, I am obviously measuring also room reflections (floor, ceiling, side walls) if the speaker is not lifted up from the floor.
Right now, I can lift up the speaker for sure to avoid the first floor reflection to be included in the gated measurement (floor reflection is at ca. 250Hz, and there is a renforcement at 500hz caused by it) , expanding the window for the gated measurement, but the question is:
Should the floor reflection be considered when projecting a crossover filter?
It is a reflection for sure, and its frequency, modes and shape will vary with distance and height of the mic, but can't really understand if it should be taken into account for developing the xover, or totally not. It's obviously possible to measure the woofer making the frequency response free from the first room reflections but in the end the speaker will sound on the ground and not lifted up. thanks a lot
I have a question.
When measuring the farfield frequency response of a 12'' woofer (3 way speaker), placing the mic at an adequate distance from baffle, I am obviously measuring also room reflections (floor, ceiling, side walls) if the speaker is not lifted up from the floor.
Right now, I can lift up the speaker for sure to avoid the first floor reflection to be included in the gated measurement (floor reflection is at ca. 250Hz, and there is a renforcement at 500hz caused by it) , expanding the window for the gated measurement, but the question is:
Should the floor reflection be considered when projecting a crossover filter?
It is a reflection for sure, and its frequency, modes and shape will vary with distance and height of the mic, but can't really understand if it should be taken into account for developing the xover, or totally not. It's obviously possible to measure the woofer making the frequency response free from the first room reflections but in the end the speaker will sound on the ground and not lifted up. thanks a lot
In ignorance, I ask. Why not?
I'm sure the engineers would take into account that the W loses some freedom in the room. At least in a late step of the XO design.
Of course a woofer down to the ground would be better.
Diyer have a lot of penalties, but at least they do not have to sell the same product to thousands of buyers.
We can adapt the artifact to the room. As long as the companies do not provide the supply of a single piece, through the online placement of the buyer's specifications.
I'm sure the engineers would take into account that the W loses some freedom in the room. At least in a late step of the XO design.
Of course a woofer down to the ground would be better.
Diyer have a lot of penalties, but at least they do not have to sell the same product to thousands of buyers.
We can adapt the artifact to the room. As long as the companies do not provide the supply of a single piece, through the online placement of the buyer's specifications.
It is practically impossible to get measurements without reflections below 500Hz, at home. IR gating to 5ms helps for higher range, but low range is painful, typically how to set W-M xo. More pain comes from that typically the woofer and mid have different elevation and thus reflections at different frequencies.
Boundaries in nearfield give boost below first null (full antiphase cancellation) and then repeating wiggles above null. The frequency where this happens depends on distance and height of source and microphone. A reflection null can not be boosted! If one does that to the signal, it just doesnt work at spot, but works in practically every other point of space in the room!
So, learn to recognize reflections and you must "equalize" the response only in your mind.
Measurements with long gating show also room's standing waves, typically below 100Hz. The lowest mode hump can be attenuated to the spot, typically around 40Hz. Higher in frequency this gets difficult and I don't recommend it, instead carefully use 2-3dB low Q attenuation (peak correction with negative gain) centered around 60Hz.
We humans have adapted to how sound behaves in a room, unlike the microphone! Moderate elevation in bass region and reflection nulls happen with natural sound sources just alike. Voicing of loudspeakers stands for trimming balance of 1/1 or 1/2 octave bands so that loudspeakers give natural sound balance. A man's speech voice is quite good for testing.
Boundaries in nearfield give boost below first null (full antiphase cancellation) and then repeating wiggles above null. The frequency where this happens depends on distance and height of source and microphone. A reflection null can not be boosted! If one does that to the signal, it just doesnt work at spot, but works in practically every other point of space in the room!
So, learn to recognize reflections and you must "equalize" the response only in your mind.
Measurements with long gating show also room's standing waves, typically below 100Hz. The lowest mode hump can be attenuated to the spot, typically around 40Hz. Higher in frequency this gets difficult and I don't recommend it, instead carefully use 2-3dB low Q attenuation (peak correction with negative gain) centered around 60Hz.
We humans have adapted to how sound behaves in a room, unlike the microphone! Moderate elevation in bass region and reflection nulls happen with natural sound sources just alike. Voicing of loudspeakers stands for trimming balance of 1/1 or 1/2 octave bands so that loudspeakers give natural sound balance. A man's speech voice is quite good for testing.
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Same logic as midrange. Do not include reflections. You could simulate the floor bounce nodes to move the woofer up or down the baffle.
Remember room modes will be room and position specific so take care of these via placement. If you were to measure and passively correct, you'd be looking at very expensive / large value components and locking your speakers to a very specific placement.
Remember room modes will be room and position specific so take care of these via placement. If you were to measure and passively correct, you'd be looking at very expensive / large value components and locking your speakers to a very specific placement.
I get best results by tuning in two stages......
Tuning the speaker as independent of reflections as possible.
Then tuning it to the room.
When i don't take the time to tune in two stages, I end up feeling I'm chasing my tail every time I move the speaker in the room, or want to alter/try something with the speaker itself. Never know what is causing what....
Plus, tuning with two separate stages teaches me what can and can't be fixed with the speaker....and how a room's acoustical problems are seldom fixed by speaker tuning.
The best way I've found to measure speakers indoors is what's shown in a video found at M-Noise
Go to 1:40 into the Real World SPL link down under M-Noise Education.
The speaker on floor, mic on floor technique, minimizes reflections about as well as can be done. Note the angle of the speaker and mic. I use it both outdoors and indoors. (I do like further than 1m when possible though.)
After I tune on the floor, and then measure the speaker at its desired location, the first step is to move the speaker around within acceptable area to restore as close as possible to the floor tuning.
The it's time to see what EQ/etc can do to help...but mostly time to find out what needs to be done to the room
If I'm not willing to do the two stage tuning, my vote is just to go with dirac or some similar room correction dsp for pure ease, and acknowledge all I want is a great one-spot tuning.
Tuning the speaker as independent of reflections as possible.
Then tuning it to the room.
When i don't take the time to tune in two stages, I end up feeling I'm chasing my tail every time I move the speaker in the room, or want to alter/try something with the speaker itself. Never know what is causing what....
Plus, tuning with two separate stages teaches me what can and can't be fixed with the speaker....and how a room's acoustical problems are seldom fixed by speaker tuning.
The best way I've found to measure speakers indoors is what's shown in a video found at M-Noise
Go to 1:40 into the Real World SPL link down under M-Noise Education.
The speaker on floor, mic on floor technique, minimizes reflections about as well as can be done. Note the angle of the speaker and mic. I use it both outdoors and indoors. (I do like further than 1m when possible though.)
After I tune on the floor, and then measure the speaker at its desired location, the first step is to move the speaker around within acceptable area to restore as close as possible to the floor tuning.
The it's time to see what EQ/etc can do to help...but mostly time to find out what needs to be done to the room
If I'm not willing to do the two stage tuning, my vote is just to go with dirac or some similar room correction dsp for pure ease, and acknowledge all I want is a great one-spot tuning.
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