It seems that the manufacturer is unwilling or unable to answer my question.
I have written to them several times before, but they never responded. This is.
Anyway, what do you think this noise could be? Is it possible that it is a cone resonance and this is completely normal, since 18" drivers are almost always offered as subwoofers for use e. g. below 100 Hz and therefore it does not matter how they behave at higher frequencies?
Has anyone experienced anything like this with an 18" (or larger) woofer?
I have written to them several times before, but they never responded. This is.
Anyway, what do you think this noise could be? Is it possible that it is a cone resonance and this is completely normal, since 18" drivers are almost always offered as subwoofers for use e. g. below 100 Hz and therefore it does not matter how they behave at higher frequencies?
Has anyone experienced anything like this with an 18" (or larger) woofer?
If you listen to music and judge what you hear, like what you recorded, that is not what it sound like in a 3-way with correct crossover.
Any 3-way sounds like that if you disconnect midrange and tweeter. You are chasing a ghost.
By the way, anything higher than 300Hz from an 18" may be critical imo. Depends on the crossover, with a 24dB/oct you may divide higher than with a 12dB/oct.
Any 3-way sounds like that if you disconnect midrange and tweeter. You are chasing a ghost.
By the way, anything higher than 300Hz from an 18" may be critical imo. Depends on the crossover, with a 24dB/oct you may divide higher than with a 12dB/oct.
PS
I had a look at the data sheet of your woofer. To me it looks capable of 500Hz for HIFI, even higher for PA use.
On the other hand, with the tiny magnet, there must be a lot of air moving to get rid of 700 Watt. For Hifi I prefer ceramic, conventionel magnets. I see no real advantage from neodym, other than wheight in PA use.
So what you hear, at high excursion in free air, should be pretty normal as air is pressed over the voice coil. With such a driver in a decend cabinet, at such excursion, you will hear nothing of this noise, as it is masked by the music. If you play music, not sine waves...
I had a look at the data sheet of your woofer. To me it looks capable of 500Hz for HIFI, even higher for PA use.
On the other hand, with the tiny magnet, there must be a lot of air moving to get rid of 700 Watt. For Hifi I prefer ceramic, conventionel magnets. I see no real advantage from neodym, other than wheight in PA use.
So what you hear, at high excursion in free air, should be pretty normal as air is pressed over the voice coil. With such a driver in a decend cabinet, at such excursion, you will hear nothing of this noise, as it is masked by the music. If you play music, not sine waves...
These all good points Turbowatch2. However what I'm talking about is not the air flow noise of the magnet system but some resonance like behaviour that is generated by higher frequencies, check comment #17 to hear.
Although maybe in a complete speaker the noise would be more masked, but if only the woofer plays, it's a very distinct and annoying noise which shouldn't be there and other woofers I tried in the same situation didn't do this.
Although maybe in a complete speaker the noise would be more masked, but if only the woofer plays, it's a very distinct and annoying noise which shouldn't be there and other woofers I tried in the same situation didn't do this.
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Okay, here is a sine sweep, the driver is in a 90 l sealed box, filled with fibreglass insulation. The noise originates from the woofer, not the box or the environment. Full of cr@p and distortion from bottom to top.
I've also tried the 1Hz sine wave and it sounds like the voice coil is rubbing, but if I gently move the cone by hand, there's no rubbing noise, only when the amp moves it.
18FX600_sine_sweep_1
I've also tried the 1Hz sine wave and it sounds like the voice coil is rubbing, but if I gently move the cone by hand, there's no rubbing noise, only when the amp moves it.
18FX600_sine_sweep_1
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OK, that sounds not healthy. At what frequency is the noise worst?
Next, I would mount the driver in the box, but magnet out in the air. Run sweep again, then feed it the frequency it is worst, from low to high volume. You should be able to find the exact source of the sound.
Are these used speakers? Did you buy them from a regular dealer or private person, described "new"?
Next, I would mount the driver in the box, but magnet out in the air. Run sweep again, then feed it the frequency it is worst, from low to high volume. You should be able to find the exact source of the sound.
Are these used speakers? Did you buy them from a regular dealer or private person, described "new"?
Double check your measurement setup. That sounds alot like when REW is glitching out. If you have another computer with REW or some other way to test I would try that first. Normally when I hear that crackle sound in a sweep I have to change the speaker channel to another in REW then change it back. You could even go to youtube and find a video with a sweep and see if it still makes that noise.
@YSDR There are a few possibilities regarding the noise. One is a bad DC output protection relay in your amp, but that usually starts as a channel independent issue from L to R sides and not commonly both channels at once, equally as noisy. It does sound alot like dirty relay contacts to me.
The next possibility is something in the crossover ie cross-coupling between the LF LP inductor and other coils close by, especially when inductors aren't orientated correctly to each other (right angles to one another). Inductor saturation distortion can also sound like that under certain circumstances with cored LP inductors, especially ferrite core types with thin windings and a small core.
On a rare occasion, I had a strange issue with some Selenium woofers, specifically WPU1507 models. When the drivers were installed, I heard a buzzing sound at specific frequencies, which also showed up as elevated H3 distortion. That turned out to be the xover, specifically the LP inductor located too close to the woofer magnet. That one took me a long time to figure out.
I recommend playing the test sweep again and carefully pushing the cone in with your hands (supported evenly on both sides) to see if the noise worsens or.improves. if the drivers have a kapton (polyimide) VC former, its possible they're deformed or blistered from previous high power abuse. The other option is loose adhesive points or a warped former inside the moving assembly. That could be caused by the VC former hitting the pole plate from over excursion. It only takes one time of that happening to permanently damage the VC. Thats more common on drivers with a flat rear pole plate, not so much with a bumped pole plate, which avoids this issue.
Your best bet is using an adjustable sine wave generator and sweeping it manually up or down to the frequency it makes noise, then leaving it at that frequency and touching/pushing/pulling on various parts of the cone, surround, dustcap and spider. That should for sure show the exact issue and isolate the symptom.
Lastly, another possibility to consider is a rubbing VC caused by uneven torqueing of mounting fasteners or mounting flange deformation of the driver basket creating a VC alignment issue. Some drivers have very.tight VC gaps and in some circumstances a rubbing VC can be the result from the slightest twist or warp in the basket when mounting screws are tightened unevenly. This is more common with cast frame drivers which have a tight VC gap as mentioned before, such as Beyma, Cervin Vega, ScanSpeak, Altec, JBL, EV to name a few. Storing large LF drivers sideways can cause the cone and VC assembly to droop sideways over a long time. Its more common on older subwoofer drivers with low Fs and soft, high compliance suspensions (acoustic suspension woofers). A driver with dual spiders and / or accordian surround rarely shows this issue.
A trick I've used before is pushing on various outer areas of cone closer to the surround and listening for any VC rubbing without a signal applied with the driver mounted and then in free air. It will usually show itself on one specific area of the cone. If it happens with the driver mounted, try loosening and tightening some of the fasteners a little while listening. Pusbing on the spider or surround edges should provoke the problem if its caused by a rubbing VC, either due to a warped former, unevenly torqued basket or uneven mounting flange.
The next possibility is something in the crossover ie cross-coupling between the LF LP inductor and other coils close by, especially when inductors aren't orientated correctly to each other (right angles to one another). Inductor saturation distortion can also sound like that under certain circumstances with cored LP inductors, especially ferrite core types with thin windings and a small core.
On a rare occasion, I had a strange issue with some Selenium woofers, specifically WPU1507 models. When the drivers were installed, I heard a buzzing sound at specific frequencies, which also showed up as elevated H3 distortion. That turned out to be the xover, specifically the LP inductor located too close to the woofer magnet. That one took me a long time to figure out.
I recommend playing the test sweep again and carefully pushing the cone in with your hands (supported evenly on both sides) to see if the noise worsens or.improves. if the drivers have a kapton (polyimide) VC former, its possible they're deformed or blistered from previous high power abuse. The other option is loose adhesive points or a warped former inside the moving assembly. That could be caused by the VC former hitting the pole plate from over excursion. It only takes one time of that happening to permanently damage the VC. Thats more common on drivers with a flat rear pole plate, not so much with a bumped pole plate, which avoids this issue.
Your best bet is using an adjustable sine wave generator and sweeping it manually up or down to the frequency it makes noise, then leaving it at that frequency and touching/pushing/pulling on various parts of the cone, surround, dustcap and spider. That should for sure show the exact issue and isolate the symptom.
Lastly, another possibility to consider is a rubbing VC caused by uneven torqueing of mounting fasteners or mounting flange deformation of the driver basket creating a VC alignment issue. Some drivers have very.tight VC gaps and in some circumstances a rubbing VC can be the result from the slightest twist or warp in the basket when mounting screws are tightened unevenly. This is more common with cast frame drivers which have a tight VC gap as mentioned before, such as Beyma, Cervin Vega, ScanSpeak, Altec, JBL, EV to name a few. Storing large LF drivers sideways can cause the cone and VC assembly to droop sideways over a long time. Its more common on older subwoofer drivers with low Fs and soft, high compliance suspensions (acoustic suspension woofers). A driver with dual spiders and / or accordian surround rarely shows this issue.
A trick I've used before is pushing on various outer areas of cone closer to the surround and listening for any VC rubbing without a signal applied with the driver mounted and then in free air. It will usually show itself on one specific area of the cone. If it happens with the driver mounted, try loosening and tightening some of the fasteners a little while listening. Pusbing on the spider or surround edges should provoke the problem if its caused by a rubbing VC, either due to a warped former, unevenly torqued basket or uneven mounting flange.
Thanks Samps, indeed it was a REW problem with the previous measurements, I changed the output device and the sweep is clean now, at least from the software side. The VC is not rubbing and the problematic aera is in the midrange I think. Maybe I hear the elevated 3rd HD around 500Hz or some IMD or both?
Here is a measurement with 500Hz LR4 low-pass (that's I will want to use with the completed speaker), the low-end distortion is probably due to the flimsy test box:
Thanks the advices profiguy but this would be an active speaker with DSP crossover, so there is no passive xo elements.
Here is a measurement with 500Hz LR4 low-pass (that's I will want to use with the completed speaker), the low-end distortion is probably due to the flimsy test box:
Thanks the advices profiguy but this would be an active speaker with DSP crossover, so there is no passive xo elements.
I think the problem you found out on your own is that 400hz is pretty high crossover point when it's also a steep crossover,
and this is more of an issue than 3rd harmonic- a low order HD that's just masked by auditory system.... It's not too exhilarating trying such crossovers with earphone/headphone either unless you are below 200hz or so.
and this is more of an issue than 3rd harmonic- a low order HD that's just masked by auditory system.... It's not too exhilarating trying such crossovers with earphone/headphone either unless you are below 200hz or so.
Please, how many times I need to write down that other woofers (e.g. Eminence Kappalite 3012LF) in the same situation with the same crossover don't sounds problematic/distorted at all.
But yeah, maybe the crossover is indeed too high for the Faital 18FX600, because it's not a midwoofer and that huge cone can resonate/distort easily.
But yeah, maybe the crossover is indeed too high for the Faital 18FX600, because it's not a midwoofer and that huge cone can resonate/distort easily.
Of course, each filter order has a different sound, which is why they are called different filter orders and thus can perform different functions. I don't think the crossover order itself is the problem here, because I wrote many times in this thread that other woofers I tried with the same filter order do not show this problem.
Moreover, even without any filter, the distortion is still audible, but it slightly masked by higher frequency content.
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IMHO a filter order and crossover frequency means very little without knowing the drivers used with it. I heard many speakers with 4th order crossover within the 250-1000Hz range and none showed a problem like this, so please go out of this thread with this theory. As I said, the distortion is there even if no filter is in use.