The stereo system errors again. With respect to the timbral errors and EQ, one can dampen the peaks a bit 1-1.5 dB. Regarding the dips, just make sure there are no dips of the reflective sound. Rather a bit more energy 1-2 kHz.
Do you have the drivers separate as well?First measurements -
Near field woofer
View attachment 313584
On-axis frequency response
View attachment 313585
Note: with the LR 48dB/oct filters it is much smoother and more flat than with LR 24dB/oct filters. Q-notch at 6500Hz is used.
But doesn't it make it easier if you choose a suitable distance between the speaker elements and then play around with various settings? You should probably calculate and simulate the whole thing first, but still. This is what Kimmosto wrote:I've designed numerous analog active and passive speaker crossover as day job and never, absolutely never, any of the highpass or lowpass filters was one of the textbook filters. Textbook filters are only useful, in very rare cases, for final acoustical target... in practice you need variable Q. You know, the textbook filter XO phase response falls apart the moment you have another slope in the vicinity, be it a natural roll-off (LF system corner frequency) or be it the XO to an adjacent way. In a two-way, these additional slopes are sufficiently far away from the XO point, but from three ways up (notably including any subwoofer XO) you cannot use any textbook XO filter function anymore as it stops summing correctly because phases are are not matching anymore. And that's just for the final target functions, mind you.
For example, if you settle for a target for low-to-mid 3rd-order XO with a constant 60 degree phase offset (because 90 degree standard 3rd order Butterworth would give more lobing issues and less efficient summing etc), how you are going to do that without free access to filter Q? As mentioned, you then must use additional PEQ and shelves to bend your fixed filter's magnitude and, much more importantly, phase to the required target. Again, that's for the target function alone, not the actual required electrical filter which is pretty much arbitrary and thus needs arbitrary control over parameters.
This project is not intended to create the SOTA speaker, it is rather about learning and evaluation of SW xover and DSP approach.
Hi PMA, that looks great.First measurements -
Near field woofer
View attachment 313584
On-axis frequency response
View attachment 313585
Note: with the LR 48dB/oct filters it is much smoother and more flat than with LR 24dB/oct filters. Q-notch at 6500Hz is used.
Hi PMA, that looks great.
Perhaps I missed it, what is the crossover point you ended up with?
Thanks, very clear. Makes sense, I think I see what you are doing.Thank you. The reply to your question is not quite simple, as the resulting acoustical characteristics are a mix of electrical and mechano-acoustical transfer functions.
However, the electrical filter scheme I used as a 1st iteration is this:
View attachment 313775
... and the corresponding EKIO filters:
View attachment 313779
This is the measured spectrogram:
View attachment 313778
This is definitely not the end of the game. Low frequencies below 40Hz have to be cut sharply, as the miniature woofer has hard times when there are such frequencies, which results in great cone excursion + distortion. Sweeps from 20Hz are now impossible, I have to start at 50Hz, even without the 150Hz/6dB shelf filter. I also plan to cut everything above some 15-18kHz, as the horn tweeter behaviour deteriorates there quickly.
Yes, I was first thinking about capacitor instead of the 1st order HP in the scheme, hopefully my amp has very low noise, so there is no issue with the noise from horn tweeter.Thanks, very clear. Makes sense, I think I see what you are doing.
Not to throw too many random suggestions... If you have any residual noise with that sensitive tweeter, you can replace your 1st DSP order filter with a capacitor (5kHz in your 1st iteration example). It would knock down any remaining noise, and provide some measure of protection against issues and accidents.
Not sure what your end purpose is, but if it's desktop/computer the limited bass isn't the worst problem, I even find the vibrations distracting.
I love these software crossovers. Very intuitive and flexible and really quick!
Good job PMA.Thank you. The reply to your question is not quite simple, as the resulting acoustical characteristics are a mix of electrical and mechano-acoustical transfer functions.
However, the electrical filter scheme I used as a 1st iteration is this:
View attachment 313775
... and the corresponding EKIO filters:
View attachment 313779
This is the measured spectrogram:
View attachment 313778
This is definitely not the end of the game. Low frequencies below 40Hz have to be cut sharply, as the miniature woofer has hard times when there are such frequencies, which results in great cone excursion + distortion. Sweeps from 20Hz are now impossible, I have to start at 50Hz, even without the 150Hz/6dB shelf filter. I also plan to cut everything above some 15-18kHz, as the horn tweeter behaviour deteriorates there quickly.
I think this is as messy (or clean ) as can be expected. I would have expected that the little woofer would be a bit wider at 2 kHz. You may try to lower the crossover point towards 2 kHz to improve things a bit.This is the normalized horizontal directivity, measured under my limited conditions. We can see that the horn tweeter is pretty directional.
View attachment 313809
Unfortunately, resonant frequency of the horn tweeter is 2.5kHz and recommended crossover frequency is 4kHz (datasheet). It does not work nice near 2kHz (distortion). Both drivers need very sharp cut - the woofer has break-ups above 4kHz and tweeter is messy below 3kHz.I think this is as messy (or clean ) as can be expected. I would have expected that the little woofer would be a bit wider at 2 kHz. You may try to lower the crossover point towards 2 kHz to improve things a bit.
Ah, do you have the distortion plot? Compression drivers can sometimes be used below its resonant frequency, but it depends highly on the particular design.Unfortunately, resonant frequency of the horn tweeter is 2.5kHz and recommended crossover frequency is 4kHz (datasheet). It does not work nice near 2kHz (distortion).
Yes, I have it, as a part of standard REW measurements .Ah, do you have the distortion plot? Compression drivers can sometimes be used below its resonant frequency, but it depends highly on the particular design.
Obviously But can you show it? I'm anyway interested in what these cheap drivers can do distortion-wise.Yes, I have it, as a part of standard REW measurements .
One "problem" I see here is the off-axis dip 1-2 kHz vs peaking at 3-4 kHz. This will exaggerate the stereo system errors since reflections in the 1-2 kHz range is a way to "fill in" the stereo system error dip. It is no solution to the problem but it is a way to milder it. I would suggest listening in stereo in a normal room and play with a bit of increase 1-2 kHz and a small dip at 3-4 kHz, but still being within +/- 1.5 dB on-axis or so.This is the normalized horizontal directivity, measured under my limited conditions. We can see that the horn tweeter is pretty directional.
View attachment 313809