8l 60Hz does not look good, I would not use this tuning. I did mine in 5-6l, tuned below 60Hz. It was not 15W revelator kind of the bass, but it was enjoyable overall, I would not definitely call it "no bass below 200Hz". You may need more bafflestep compensation.
The 2way below, I did direct comparison to KEF LS50 Meta passive, and I liked Sica coax better, more relaxed and balanced sound. KEF sounded little shouty and cuppy.
The 2way below, I did direct comparison to KEF LS50 Meta passive, and I liked Sica coax better, more relaxed and balanced sound. KEF sounded little shouty and cuppy.
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Very interresting. I double checked SICA website - manufacturer did some measurements with 9L 58Hz tuned box, so I am not far from it.
Another mention by manufacturer is 8L 68Hz box.
My 8.5L box:
It is a picture from Vituixcad from your sim? I cannot get such curve as yours on 5-6L enclosure
Try 5l in your sims. The peaking will get flat.
Manafacturers use various cabinets to measure the drivers. It is not meant to provide good woofer alignment a sound good.
Manafacturers use various cabinets to measure the drivers. It is not meant to provide good woofer alignment a sound good.
Ok, I tried 5L sims: what tuning you recommend? 60Hz?It looks good with only ~70Hz and around it.
And another clarification - yes, I know the peaking is kind of bad, but the idea is to get some bass from it. I always thought that ~2dB "peak" is not much to worry about. It will be even less after some minor stuffing. I have built some projects with such simulated peaks - they are not troublesome IMHO. Do this peak impact some other sound qualities in lower freq (with this driver)?
And another clarification - yes, I know the peaking is kind of bad, but the idea is to get some bass from it. I always thought that ~2dB "peak" is not much to worry about. It will be even less after some minor stuffing. I have built some projects with such simulated peaks - they are not troublesome IMHO. Do this peak impact some other sound qualities in lower freq (with this driver)?
@svp: I have only used the Sica Coax as dedicated midrange ie no bass. There is no mention of the box from Sica datasheet. We dont now efternal dimensions.
I guess as @PKAudio mentioned, Maybe you did not properly account for baffelstep. Ie worst case lower bass is -6 dB lower than midrange. Result is feeling of no bass at all.
I guess as @PKAudio mentioned, Maybe you did not properly account for baffelstep. Ie worst case lower bass is -6 dB lower than midrange. Result is feeling of no bass at all.
There definitely is. Twice. On the first page it is mentioned 8L 68Hz, and on the second - 9L 58Hz. So smth in between is a good starting point. Right?
https://sica.it/wp-content/uploads/2023/12/Z002810.pdf
Baffle is exactly the size of the driver ext dimensions and even smaller - part of it is printed with 3d printer, another part is bent cardboard-foamboard. Basically it is on the side of the cylinder, just more on the top.
IMPORTANT UPDATE: I rechecked my all the settings in EQ APO, preamp (Presonus Studio 26c - there are no settings after all), changed amplifier, from shitty Topping MX3 to another shitty and as a bonus also noisy with hissing sounds FXAUDIO FX5025 Pro. Both of them are fed with almost identical 24V supplies. There is some simple EQ inside MX3, but it was set to 0. And a little miracle happened: now the bass is here! This speaker is not transformed to the subwoofer, but now the low notes are full of energy, the sound is more or less as supposed to be. Why I am so sure that the sound is transformed? Because the speaker is on the table with computer, and with similar SPL now the table is rattling a little. I did NO changes to the EQ APO file. No other changes also - just changed the amp.
Still not suitable for dance parties, but old Love Parade motives are listenable
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Nice you found the issue!
Yes, but we dont know the dimensions of the bafle. I admit they properly measured in rather Small bafle, but we dont know for sure.
Bafflestep (BS) is basically loss of bass depending of baffle dimensions and room placement of speaker.
We can simplify even further and say main determine factor is baffle width.
In perfect scenario with flat response of driver in infinity baffle, BS can be roughly calculated with 115/(width of baffle in meter). 16 cm = 115/0.16.
Reality is not so simple and if you just measure 1 meter distance and no gating, what you see on graph is totally masked from influence of reflections of the room.
Good practice is this:
Nearfield of port+ nearfield of driver (not gated). Merge with farfield (gated).
Use diffraction tool in VCad.
Then continue simulation of filter from there.
I admit also that Sica Coax is quite challenging to get good results. One has to accept that smooth on axis and off axis is not possible (at least not in my non perfect baffle). But fun it sure is.
I would also rate Sica in at least same ballpark as Kef LS50.
1. Nearfield of port+ nearfield of driver (not gated).
2. Merge port + driver
3. Use diffraction tool in VCad.
4. Merge with farfield (gated).
Baffle step are fluctuations in the range of ~6dB, and in reality closer to ~3-4dB with real life boxes. In my case baffle step is in ~750Hz range, baffle shape is round, and the problem was in <200Hz range with amplitude in 10dB or even more in all the low Hz range. I am not so good at understanding diffraction around whole box sides, but in this case it was 100% not baffle step problem.
Amp is the primary cause and lesson learned - try everything you have at hand. It seems that those TPAXXXX amps are not only pleasant to listen, but also much more accurate than others in my zoo of audio junk: that includes 3116 and 3250 series. I never liked that Topping amp, and now my suspicions are confirmed.
Also: the timbre overall is MUCH more pleasant now. No metalic-plastic sound anymore. This driver went from looking as hi-fi to being hi-fi
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Clarification: tweeter steps are the same except port, right?
And if it is coax unit - how far from surface of the woofer I should put mic? It is not possible to put it directly on the center and very close, as the tweeter occupies center. Side? Center as close to tweeter, just on the same position as measuring tweeter - do not touch the mic, just switch amp from tweeter to woofer?
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You don't need nearfield measurements, because gated farfield will allow accurate measurement for the entire tweeter range.
Mic distance should be enough to include baffle diffraction influence, so I guess 50 cm to 1 m should be good.
There is a very good description in vituixcad help/manual how to do measurements:
https://kimmosaunisto.net/Software/VituixCAD/VituixCAD_Measurement_REW.pdf
I like all the Kimmo did for the community, really grateful for that, but this manual is... So much different to the other methodic I found on the internet.
Probably need more idiot-proof steps, like in your post before this one.
To get enough baffle-step as well as diffraction information, 1 meter is basically the minimum.
If that's not possible you basically have to guess and "average" between measurements and simulations of the baffle.
But even that is pretty doable, unless you have a very crazy shaped baffle.
Two other alternatives for baffle/diffraction simulations are Edge (Tolvan) and Boxsim.
Both have been around for a very long time.
They all offer quite similar results, so it might just come down to which workflow and interface you prefer.
Both have been around for a very long time.
They all offer quite similar results, so it might just come down to which workflow and interface you prefer.
Is that "1meter plus" because of the a) wavelengths, b) wavelength/room dimensions ratio or c) distance to the mic and baffle width ratio?
For example: if my baffle is ~17cm width will I get more accurate results at 1m than if my baffle is ~34cm.
I emailed Sica out of curiosity and they kindly sent me some CAD files for the 5.5C1.5CP and the 4C1.5CP. I replicated the profiles into an Ath4 script and the results are pretty cool. I "validated" the sim by comparing directivity with the Donhighend Fianco build, and it seems to match very well.
Looking at the curved profile of the surround and the basket, it's pretty obvious to use a very narrow baffle to minimize diffraction, and as always, with a fair amount of roundover or chamfer. Just a 6mm chamfer with a 158mm wide baffle seems to almost completely remove the diffraction around 2-3kHz. I almost feel bad about all the builds hardly paying any attention to this.
Also made an axisymmetric sphere-like enclosure with a roughly continuous profile. I think a KEF-like flange covering some of the surround might help with the funk around 8kHz or so, as the innermost accordion kinda protrudes from the overall profile - will sim further
Only tried the 4C quickly in a small enclosure - couldn't make IB work for some reason. Seems pretty decent as well, I don't care much about the top octave
Looking at the curved profile of the surround and the basket, it's pretty obvious to use a very narrow baffle to minimize diffraction, and as always, with a fair amount of roundover or chamfer. Just a 6mm chamfer with a 158mm wide baffle seems to almost completely remove the diffraction around 2-3kHz. I almost feel bad about all the builds hardly paying any attention to this.
Also made an axisymmetric sphere-like enclosure with a roughly continuous profile. I think a KEF-like flange covering some of the surround might help with the funk around 8kHz or so, as the innermost accordion kinda protrudes from the overall profile - will sim further
Only tried the 4C quickly in a small enclosure - couldn't make IB work for some reason. Seems pretty decent as well, I don't care much about the top octave
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My results. BR ~7.7L (not including the vent), tuned to ~59Hz, with some stuffing, probably ~100g. Custom 3D printed baffle. Will try to make even smaller box with a bit higher tuning. Below my rookie builder opinions and screenshot. Critique is welcome.
Currently listening from PC with EQ APO virtual crossover, from passive elements only, with convolver export from VituixCAD, measurements for simulation done with Sonarworks calibrated mic, which I trust more or less, 15 degree steps only in horizontal impedance - with simple 100Ohm "rig". I feel I am 90-95% of what can be squeezed from this driver as 2-way system with reasonable crossover. Next step is for me to measure it again and to build real crossover.
Pros:
-Good driver. Hifi. Worth building a project. Not something in between. Well built, heavy, strong. Survived couple of drops from 1-1.2m heights while in test box... (facepalm) - will not survive if membrane is touched.
-Good looking - already mentioned. Will repeat, as it looks as if has some designer pedigree
-Detailed on a very broad range - lows, mids, highs.
-Pretty pleasant timbre. On the warmer side, still a bit too sharp/detailed for late night listening.
-In the nearfield it is a true coax experience: on some songs I even start to look at the driver to check if there is really someone playing inside the speaker?Daft Punk RAM sounds so cozy and good with it. This is probably one of the first times, when I look with eyes into mono playing speaker and try to locate... synthesizer
-Can make pretty flat SPL response with reasonable x-over. Screenshot attached.
-For those measuring sound quality in numbers, it is possible to squeeze a score of 7.1-7.2 Mr. Saunisto-VituixCAD coefficient with some tuning and a bit more complex passive xover. I stopped at ~6.9 (~7.05 on 10 and 20 degrees hor), because want simplicity, little BBC dip and some other personal preference. Screenshot attached.
Cons:
-Very VERY sensitive to small changes in (virtual) crossover. For example in one step in some element from 1.2 to 1.5uF or vice versa, or even smaller - you can get unlistenable sound. One small change in resistor - also.
-Very VERY sensitive to small changes in baffle size and shape - again from "wow, how good it sounds" to "smth is VERY wrong " only 3-5cm, even if it is rounded and 3D printed in both cases. My advice from personal preference is narrow very rounded baffle for this project.
-Midrange from 1-4kHz is hard to simulate: couple dB too high, and the speaker is unlistenable, couple of dB too low - it sounds extremely boxy. Personally think there is very narrow window where it sounds right/neutral.
-Little bass. It plays more like 4.5inch speaker. I tried to build bigger box, but the quality suffers, probably will get limited by excursion very soon. Need some 2.5 with other SICA non-coax 5inch or proper 3-way for primary system. Don't get me wrong, for a bookshelf or tabletop speaker it is MORE than enough. Subwoofer crossed to 100-120Hz will solve most of the deficiency problems.
-Woofer SPL needs to drop fast past 3-3.5kHz, as sound above gets distorted a lot, you can hear with ears without measuring, so need pretty aggressive filter.
Ignore this measurement thing of ~600Hz, this is because of the stand. The baffle is custom. You will get very different results in ~1-3kHz, the region which is very sensitive for this driver.
Comments are more than welcome
Currently listening from PC with EQ APO virtual crossover, from passive elements only, with convolver export from VituixCAD, measurements for simulation done with Sonarworks calibrated mic, which I trust more or less, 15 degree steps only in horizontal impedance - with simple 100Ohm "rig". I feel I am 90-95% of what can be squeezed from this driver as 2-way system with reasonable crossover. Next step is for me to measure it again and to build real crossover.
Pros:
-Good driver. Hifi. Worth building a project. Not something in between. Well built, heavy, strong. Survived couple of drops from 1-1.2m heights while in test box... (facepalm) - will not survive if membrane is touched.
-Good looking - already mentioned. Will repeat, as it looks as if has some designer pedigree
-Detailed on a very broad range - lows, mids, highs.
-Pretty pleasant timbre. On the warmer side, still a bit too sharp/detailed for late night listening.
-In the nearfield it is a true coax experience: on some songs I even start to look at the driver to check if there is really someone playing inside the speaker?Daft Punk RAM sounds so cozy and good with it. This is probably one of the first times, when I look with eyes into mono playing speaker and try to locate... synthesizer
-Can make pretty flat SPL response with reasonable x-over. Screenshot attached.
-For those measuring sound quality in numbers, it is possible to squeeze a score of 7.1-7.2 Mr. Saunisto-VituixCAD coefficient with some tuning and a bit more complex passive xover. I stopped at ~6.9 (~7.05 on 10 and 20 degrees hor), because want simplicity, little BBC dip and some other personal preference. Screenshot attached.
Cons:
-Very VERY sensitive to small changes in (virtual) crossover. For example in one step in some element from 1.2 to 1.5uF or vice versa, or even smaller - you can get unlistenable sound. One small change in resistor - also.
-Very VERY sensitive to small changes in baffle size and shape - again from "wow, how good it sounds" to "smth is VERY wrong " only 3-5cm, even if it is rounded and 3D printed in both cases. My advice from personal preference is narrow very rounded baffle for this project.
-Midrange from 1-4kHz is hard to simulate: couple dB too high, and the speaker is unlistenable, couple of dB too low - it sounds extremely boxy. Personally think there is very narrow window where it sounds right/neutral.
-Little bass. It plays more like 4.5inch speaker. I tried to build bigger box, but the quality suffers, probably will get limited by excursion very soon. Need some 2.5 with other SICA non-coax 5inch or proper 3-way for primary system. Don't get me wrong, for a bookshelf or tabletop speaker it is MORE than enough. Subwoofer crossed to 100-120Hz will solve most of the deficiency problems.
-Woofer SPL needs to drop fast past 3-3.5kHz, as sound above gets distorted a lot, you can hear with ears without measuring, so need pretty aggressive filter.
Ignore this measurement thing of ~600Hz, this is because of the stand. The baffle is custom. You will get very different results in ~1-3kHz, the region which is very sensitive for this driver.
Comments are more than welcome