I'm after an in box measurement of an A26RE4 - with known baffle dimensions please.
I am dubious of the Seas posted curve. I know Seas use an inbox measurement as stated in the conditions (28L) but unsure how they have determined the bass / lower midrange response. To me - it looks like they are showing an infinite baffle response and not the in box with baffle step response.
i.e. I'd expect this driver if nominally 88.5dB sensitive to show about 3 - 4 dB less output at 100Hz than the stated ~ 89dB in the attached image.
Any thoughts please?
Edit: If the A26 has built in "BSC" then thats good. I'm just concerned most of the kits I've seen assume 89dB sensitivity - about that of the woofer above the baffle step. So I'm wondering how these designs sound.... whether they are a bit thin.
I am dubious of the Seas posted curve. I know Seas use an inbox measurement as stated in the conditions (28L) but unsure how they have determined the bass / lower midrange response. To me - it looks like they are showing an infinite baffle response and not the in box with baffle step response.
i.e. I'd expect this driver if nominally 88.5dB sensitive to show about 3 - 4 dB less output at 100Hz than the stated ~ 89dB in the attached image.
Any thoughts please?
Edit: If the A26 has built in "BSC" then thats good. I'm just concerned most of the kits I've seen assume 89dB sensitivity - about that of the woofer above the baffle step. So I'm wondering how these designs sound.... whether they are a bit thin.
Last edited:
Theres nothing wrong with Seas measurement. Due high value of Le that driver has built-in BSC compensation.
Plus, 25 liters is smal box for 10in, resulting in high system Q, further boosting the low end.
For independent measurements, dibirama made it on IEC baffle:
https://dibirama.altervista.org/home-page/woofer/131-seas-a26re4-woofer-10-8-ohm-80-wmax.html
I have account there, if you want frd/zma files I can download them for you.
Plus, 25 liters is smal box for 10in, resulting in high system Q, further boosting the low end.
For independent measurements, dibirama made it on IEC baffle:
https://dibirama.altervista.org/home-page/woofer/131-seas-a26re4-woofer-10-8-ohm-80-wmax.html
I have account there, if you want frd/zma files I can download them for you.
Thanks for the link. I've registered and downloaded.
However - the measurement there is on an IEC baffle - not in box with baffle step losses - correct?
I've used similar inductance woofers and unsure how high inductance solves baffle step. I thought high inductance helped with natural acoustic rolloff (LP).
I'm helping someone who wants to run the A26 ported in a large box - therefore a small box / high Qtc won't be boosting the low end, so I want to be careful advising him on overall system sensitivity (and obvious cone unloading / excursion issues).
However - the measurement there is on an IEC baffle - not in box with baffle step losses - correct?
I've used similar inductance woofers and unsure how high inductance solves baffle step. I thought high inductance helped with natural acoustic rolloff (LP).
I'm helping someone who wants to run the A26 ported in a large box - therefore a small box / high Qtc won't be boosting the low end, so I want to be careful advising him on overall system sensitivity (and obvious cone unloading / excursion issues).
In the below Graph
PURPLE = dibrana IEC baffle measurement
RED = Seas in 28L box measurement
GREEN = My estimated in box measurement allowing for baffle step (I took the PURPLE dibrana IEC measurement, subtracted the IEC baffle response and added in the in 110L vented box model plus box diffraction via frequency response combiner)
Interestingly I get using an original IEC baffle measurement, a similar baffle diffraction profile from 300Hz up compared to Seas.
This leads me to believe my baffle size is similar to Seas meaning the farfield response can be relied upon.
I however cannot understand how the bass response from Seas can be close to IEC levels if they did a full sweep (Assuming anechoic) in BOX measurement.
PURPLE = dibrana IEC baffle measurement
RED = Seas in 28L box measurement
GREEN = My estimated in box measurement allowing for baffle step (I took the PURPLE dibrana IEC measurement, subtracted the IEC baffle response and added in the in 110L vented box model plus box diffraction via frequency response combiner)
Interestingly I get using an original IEC baffle measurement, a similar baffle diffraction profile from 300Hz up compared to Seas.
This leads me to believe my baffle size is similar to Seas meaning the farfield response can be relied upon.
I however cannot understand how the bass response from Seas can be close to IEC levels if they did a full sweep (Assuming anechoic) in BOX measurement.
