Speaker Measurements

[nerddude]

I am working on active crossover design for my speakers.Trying to figure out best way to take measurements.Unfortunately outside is not very quiet for measurements.
If i have to do them indoors what is the best way to get good measurements.

 

[AllenB]

Big topic. Where are you at and what is your concern?

 

[nerddude]

I had done measurements with speaker at location where its going to be in room. Microphone within 1 inch of each driver.
But when i look at impulse response its bad.
So wondering if need a different approach.

 

[AllenB]

Reflections. Take it away from the wall and use gating.

 

[markbakk]

‘Reading’ an impulse response is hard. Most of us convert them into SPL vs frequency plots, CSD or BD plots. But Allen is right, learn how to measure. I’m not advocating things, but have a look here, for instance.

 

[hollowboy]

"I am working on active crossover design for my speakers." Are these finished speakers (cabinets already built) or are you still in the design stage?

If the latter, some enthusiast / semi pro pages have a section of hints and tips:

http://www.troelsgravesen.dk/measurements.htm

http://www.zaphaudio.com/setup.html

 

[warrjon]

There is a lot of information on Linkwitz site regarding how he went about measuring speakers and how to design a good baffle. You'll have to dig through his postings to glean the relevant information, but it'll give good insight as to how to design speakers.

There is more to a great in-room sounding speaker than flat on-axis frequency response. SL goes into how off axis response shapes in-room power response, which is what we actually hear. After building LXmini+2's I set about building LX521 inspired OB and these are the best speaker I have heard in my room, it dose not matter where in the room I sit the sound stage never collapses into one speaker it's always radiating from behind the speakers.

I measured mine in my shed as it's big, but before I had this I measured in-room with driver 1/2 way between floor and ceiling, mic 500mm from driver and appropriate gating. Lower frequencies ie subwoofer was measured with mic on the floor. Hope this helps

 

[jReave]

From the late, great Jeff Bagby:

https://app.box.com/s/fefis558wna1d6pd07r3

 

[nerddude]

‘Reading’ an impulse response is hard. Most of us convert them into SPL vs frequency plots, CSD or BD plots. But Allen is right, learn how to measure. I’m not advocating things, but have a look here, for instance.

Thank you

 

[nerddude]

From the late, great Jeff Bagby:

https://app.box.com/s/fefis558wna1d6pd0

Thank you

‘Reading’ an impulse response is hard. Most of us convert them into SPL vs frequency plots, CSD or BD plots. But Allen is right, learn how to measure. I’m not advocating things, but have a look here, for instance.

Thank you

 

[jjasniew]

Unfortunately outside is not very quiet for measurements.

Certainly you could blast over anything else with a mic 1 meter in front? Or wait for your chance in time to do a sweep. If it's more like you cant play anything loudly outside, well, that's understandable.

I've taken outdoor measurements where I know a particular spike is the airplane flying overhead...

 

[markbakk]

Outside measurements in a noisy environment? Use multiple measurements (5 should do) and even the noise out. Be sure to use 2channel measurement with timing reference on one channel though.

 

[TMM]

If all you're trying to measure is frequency response, then measuring the speakers at 90-100dB SPL should easily swamp out any outside ambient noise, unless you live right next to an active freeway.