Hello
Last year I started a new project, replica of Troels 61-NAC, but I faced some weird tweeter behaviour especially in top end.
TBH it's not audible (at least in my ears).
What causes that strange tweeter ringing
1. Unproper measurement
2. Tha stepped baffle shape
3. Something else
Tweeter SB26ADC-C000-4
Measurement equipment
Mic UMIK-1
External SC Behringer UCA202
Amp Denon PMA-520AE
REW
That is baffle shape H390 W190mm
step 19mm
That's are the measurements
Tweeter is on baffle no crossover applied.
Distance 1meter on axis tweeter level
Gated measurement w 3.5ms window
Thank you in advance
Greetings
Last year I started a new project, replica of Troels 61-NAC, but I faced some weird tweeter behaviour especially in top end.
TBH it's not audible (at least in my ears).
What causes that strange tweeter ringing
1. Unproper measurement
2. Tha stepped baffle shape
3. Something else
Tweeter SB26ADC-C000-4
Measurement equipment
Mic UMIK-1
External SC Behringer UCA202
Amp Denon PMA-520AE
REW
That is baffle shape H390 W190mm
step 19mm
That's are the measurements
Tweeter is on baffle no crossover applied.
Distance 1meter on axis tweeter level
Gated measurement w 3.5ms window
Thank you in advance
Greetings
Did you measure it where it is placed in the photo? If so the cabinet to the right could be causing some nasty reflections. I looked at the factory measurements and this tweeter looks very flat between 1kHz and 18kHz.
It could be this, but 15-20kHz wave is around 3-1,5cm length, so the problem may be at this distance from tweeter. The first problem starts at ~7kHz, which is ~5cm wavelength - exactly distance form baffle step!
Or the tweeter can be just bad. Another one from the pair measures the same?
Besides, it is strange why the OP still used so much "yesterday" tech of stepped baffle, when there is something what has only benefits and not much drawbacks: waveguide!
My living room is about 3.5m (11ft) wide.
During the measurements the speaker and the mic were on the equal distances from the side walls and 1.2m (~4 ft) from the floor and the ceiling.
After the tweeter I measured the midwooffer and the response was just OK.
During the measurements the speaker and the mic were on the equal distances from the side walls and 1.2m (~4 ft) from the floor and the ceiling.
After the tweeter I measured the midwooffer and the response was just OK.
Cabinet edges cause reflections but not ringing. It is good to test condition of sound card, amp and UMIK with REW.
Good SB26ADC-C000-4 have clean waterfall: https://hificompass.com/en/speakers/measurements/sbacoustics/sb-acoustics-sb26adc-c000-4
Good SB26ADC-C000-4 have clean waterfall: https://hificompass.com/en/speakers/measurements/sbacoustics/sb-acoustics-sb26adc-c000-4
i'm not sure if it is ringing or reflections.
The only way to find out I will have to make another measurement on some plane baffle.
If they are of sufficient angular resolution to see the issue.
These are the waterfalls measured in 15 degree increment
Hope that will help.
Аfter reading the comments I am convinced the problem is caused by the edge of stepped baffle.
Hope that will help.
Аfter reading the comments I am convinced the problem is caused by the edge of stepped baffle.
I know the dome breakup is at 16-17kHz. Anyway it's out of the hearing range.
I'm curious about the constant dips at 7.3kHz. They not seem to be due tweeter's ringing, but some reflections from the step's edge. Am I right?
I guess Troel's desighn has the same drawbacks.
For sure I'll try to find some appropriate waveguide.
I'm curious about the constant dips at 7.3kHz. They not seem to be due tweeter's ringing, but some reflections from the step's edge. Am I right?
I guess Troel's desighn has the same drawbacks.
For sure I'll try to find some appropriate waveguide.
Can this "ringing" be reflections from room? Long time also indicates that it cannot be caused by diffraction from edges of front panel.
Is speaker located, when measured, as far from any item in room as possible?
Is front panel attached to rest of the case only with tapes as can be seen on image? Maybe front panel itself is ringing?
Have you any other speakers/tweeters in other case, can you measure them to exclude sound card, amp and UMIK problems?
Is speaker located, when measured, as far from any item in room as possible?
Is front panel attached to rest of the case only with tapes as can be seen on image? Maybe front panel itself is ringing?
Have you any other speakers/tweeters in other case, can you measure them to exclude sound card, amp and UMIK problems?
It's unlikely as the first impulse reflection appears around 3.8ms and I set the window at 3.5ms.
The baffle is fitted very tight into the box as I made 1cm rebate around. But such a possibility still exists.
Yes I have another speaker and I will try when I have more time.
