Hello, I'm intrested in building this open kit SBAcoustics-61-NRXC with newer SB acoustics woofer SB17NRX2C35-4 (main reason beacause I already have drivers🙂).
I read this article www.audioexcite.com >> Blog Archive >> SB17NRX2C35-4 vs SB17NRXC35-4 and how I understand drivers almost interchangeable but still need some tweeks. In past builded couple of kit's but never designed a crossover. So how could I figure out those tweeks ? Just try to put this crossver in some sort of crossover design software ? And also in the article is this sentence "Also, another factor to consider is that if combining the two NRX versions with the same tweeter, the drivers relative acosutical off-set is about 3-4mm larger using the new NRX2 driver compared to the old NRX driver." What is relative acosutical off-set? Information that I managed found myself was to technical to understand.
I read this article www.audioexcite.com >> Blog Archive >> SB17NRX2C35-4 vs SB17NRXC35-4 and how I understand drivers almost interchangeable but still need some tweeks. In past builded couple of kit's but never designed a crossover. So how could I figure out those tweeks ? Just try to put this crossver in some sort of crossover design software ? And also in the article is this sentence "Also, another factor to consider is that if combining the two NRX versions with the same tweeter, the drivers relative acosutical off-set is about 3-4mm larger using the new NRX2 driver compared to the old NRX driver." What is relative acosutical off-set? Information that I managed found myself was to technical to understand.
Jo0, you have missed something rather important:
SBAcoustics-61-NRXC
Troels uses the 8 ohm version of the midbass!
It's not going to be easy to adjust for that.
Two circuits here for the Mark 1 version of your driver:
Small studio monitor using SB Acoustics SB17CRC35-4 and SB29RDNC-C000-4
4mm extra offset on the Mark 2 midbass will just tilt the lobe down a tidge. They will sound better below axis to a slight extent, but 4mm is next to nothing really. It would take a sim to sort that out.
The second circuit is probably better if the notch is accurate. Again it would be good to sim it to see how it works. But I expect either will sound alright without adjustment.
SBAcoustics-61-NRXC
Troels uses the 8 ohm version of the midbass!
It's not going to be easy to adjust for that.
Two circuits here for the Mark 1 version of your driver:
Small studio monitor using SB Acoustics SB17CRC35-4 and SB29RDNC-C000-4
4mm extra offset on the Mark 2 midbass will just tilt the lobe down a tidge. They will sound better below axis to a slight extent, but 4mm is next to nothing really. It would take a sim to sort that out.
The second circuit is probably better if the notch is accurate. Again it would be good to sim it to see how it works. But I expect either will sound alright without adjustment.
Thank you for your response.
So this crossover made for EKA box in wich tweeter is of center yes ?
I tried to use Xsim but I having hard time to finding FRD files.
So this crossover made for EKA box in wich tweeter is of center yes ?
I tried to use Xsim but I having hard time to finding FRD files.
The Eka is a flat baffle. 200mm wide, 12-15L. Centred tweeter.
There's two ways to go here. Either adjust Troels' bass filter for 4 ohms ( Actually 3.1R versus 5.7R in your case) and allow for tweeter loudness with any different tweeter. This is stepped baffle, of course. The SB26ADC is well liked as it goes:
SB26ADC-C000-4 / Aluminum – Sbacoustics
The SB26TAC is 2dB louder:
SB26STAC-C000-4 / Fabric – Sbacoustics
Or you adapt the second EKA circuit for the SB17NRX2C35-4.
6″ SB17NRX2C35-4 / Norex – Sbacoustics
Your woofer has a sharpish breakup peak at 6kHz, so the notch should be placed there. Probably around 3.9uF/0.2mH/2.2R, but you can check that.
If you don't rebate your woofer, that should fix the 4mm acoustic offset change.
There's two ways to go here. Either adjust Troels' bass filter for 4 ohms ( Actually 3.1R versus 5.7R in your case) and allow for tweeter loudness with any different tweeter. This is stepped baffle, of course. The SB26ADC is well liked as it goes:
SB26ADC-C000-4 / Aluminum – Sbacoustics
The SB26TAC is 2dB louder:
SB26STAC-C000-4 / Fabric – Sbacoustics
Or you adapt the second EKA circuit for the SB17NRX2C35-4.
6″ SB17NRX2C35-4 / Norex – Sbacoustics
Your woofer has a sharpish breakup peak at 6kHz, so the notch should be placed there. Probably around 3.9uF/0.2mH/2.2R, but you can check that.
If you don't rebate your woofer, that should fix the 4mm acoustic offset change.
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Different driver I know but here was my build with an SB17.
Post #6 has the XO values
SB17NBAC35-4 with DA25BG08-06 project in Leak boxes
Post #6 has the XO values
SB17NBAC35-4 with DA25BG08-06 project in Leak boxes