Hi all, I am attempting to measure individual drivers sans XO mounted on the actual speaker baffle. I am getting reflections as you can see from the Impulse response. I have been trying to find the source of the reflection to minimize it. Not sure if you would consider it a deal breaker or not to making good measurements. I am using Omni Mic with a stand the measurement in this case is the midrange and it is 32 in off the floor. I measure it on axis near and at 24 inch away with similar results. My first instinct was that it could be the room, then I checked the from baffle. not sure what else it could be. Clues would be helpful for the experienced builders out there. TY!!
Attachments
Usually, the obstacle that's nearest to the loudspeaker is the floor, but you say it's 32 inches from it !! If you mean the bump in your impulse response at 0.5ms, then that could be the driver (or some part thereof).
Last edited:
The nearest boundary noramlly indeed.
If your timing is right, it is only a half msec from the initial impulse.
thats a little over foot under standard conditions.
The mic stand and mic will also cause a reflection in the measurement. Did you check that?
Especially if you dont take measures to avoid it, the default Omnimic stand is short and fat ontop of it all.
And since it is so short it is standing on something?
Measure something else, and see if you get the same. My hunch is that it's actually the speaker, but without seeing the setup, that's a guess. Any stuffing in the box? Is there a box, or just a baffle?
You could show us the response gated out to 3ms, then maybe 4ms. Also show the impulse further out.
You could show us the response gated out to 3ms, then maybe 4ms. Also show the impulse further out.
Last edited:
@ThatSoundsGood I agree with you. No matter what I do I cant get rid of it. My suspicion is that the box for the mid is a bit small and it does not have enough stuffing. reflection off rear wall possible??
I would need a lot more information to determine that. Box dimensions, driver used, internal stuffing, is the box properly sealed and braced, on-axis frequency response and a waterfall chart. If you can measure with REW and send me the measurements I could look at it.
![PXL_20250407_164659388[1].jpg](/community/data/attachments/1353/1353612-aad9a4f04256bd1d9078ca257b33f4d5.jpg?hash=yf_Lq-O0qV)
![PXL_20250407_164710251[1].jpg](/community/data/attachments/1353/1353613-c4aef48f043812d091bc44542d231c20.jpg?hash=RAWsSu-pe0)
It could potentially be a reflection off of the waveguide of the mid woofer. But it's likely just the woofer. Here is a picture of the impulse response of a ScanSpeak mid-woofer. You can see the first reflection around 3.6ms. Everything before that is the speaker.
Attachments
Hi Jim Cool for the photos 👍
Nothing to say about your measurement in your first post. You should upload a photo with a longer time windows at least 6ms. We will see if you have a reflection ?
This is a other typical measurement of a 4" mid MU10RB in my latest project, the first reflection is 4.6 ms. You always have ripple in the first ms.
Nothing to say about your measurement in your first post. You should upload a photo with a longer time windows at least 6ms. We will see if you have a reflection ?
This is a other typical measurement of a 4" mid MU10RB in my latest project, the first reflection is 4.6 ms. You always have ripple in the first ms.
It will be interesting to see the impedance plot.
Peaks there may indicate a strong internal reflection.
Peaks there may indicate a strong internal reflection.
Hi Jimbones,
is that the impedance of the "single" driver without crossover?
If yes, something is wrong, the second peak around 800Hz shouldn't be there
is that the impedance of the "single" driver without crossover?
If yes, something is wrong, the second peak around 800Hz shouldn't be there