The J-Box has some big problems, according to the reviewer its not suitable for chassis evaluation due to high noise, which means you need more external devices like a separate AMP or Microphone.
Member
Joined 2003
It's noise level is acceptable, similar to what you would expect from a budget USB audio interface. You may find measurements in my review of the noise floor (white trace)
...and I produced clean impedance measurement with the device:
...and I produced clean impedance measurement with the device:
We have it so good in the modern era, sometimes we forget how things used to be.
In 1991 measuring speakers costed US$4500 = $10,000 in 2025
“when I compare it to my system from 1991. The PC alone cost me $1500 and the MLSSA card and software added another $3000 to that”
Reference:
https://www.linkwitzlab.com/frontiers_6.htm#Y -
In 1991 measuring speakers costed US$4500 = $10,000 in 2025
“when I compare it to my system from 1991. The PC alone cost me $1500 and the MLSSA card and software added another $3000 to that”
Reference:
https://www.linkwitzlab.com/frontiers_6.htm#Y -
Member
Joined 2003
I just ran some basic measurements, the intent of the review was mostly to show that the device is well functioning, not a scam or junk hardware, so there is less risk for anyone interested in purchasing and using it. Certainly a country mile better than some junk Behringer UCA202/222 that some have attempted to use for measurement purpose. Mentioned in my review, "I tested a high end speaker at 315mm, using the 4.9V output. Calibrated the mic SPL level, and adjusted the gain of both the M4 and Jbox to have 120dB of headroom. Actual SPL at the mic for this test is in the 96-97dB range."
I've not encountered any issue with linearity on any of the usb interfaces I've used (Scarlett 2i2, Steinberg UR22mkii, Motu M4), condenser mics are quite sensitive, I use a similar gain setting for either line or mic input. Mic input is often a higher impedance input than line level, perhaps is part of the issue you've encountered.
Give me a little time, I can compare noise floor level and gain setting linearity with mic input.
I've not encountered any issue with linearity on any of the usb interfaces I've used (Scarlett 2i2, Steinberg UR22mkii, Motu M4), condenser mics are quite sensitive, I use a similar gain setting for either line or mic input. Mic input is often a higher impedance input than line level, perhaps is part of the issue you've encountered.
Give me a little time, I can compare noise floor level and gain setting linearity with mic input.
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