Yes of course. I'm running the DSP engine in Roon with FIR filters.
I reckon that I now would have to EQ about -10dB to get to the same level as in the HF.
But it comes with a cost of more wattage and also heat dissipation problems in the membrane itself.
So every dB counts above 10kHz.
I reckon that I now would have to EQ about -10dB to get to the same level as in the HF.
But it comes with a cost of more wattage and also heat dissipation problems in the membrane itself.
So every dB counts above 10kHz.
then again above 10khz there is less and less content. so not sure if that extra 10db is a problem. i did notice foils with an aluminium tape can handle quite some power because the adhesive kind of isolates the alu from the mylar. the laminates i have here really have a problem with power handling because the glue layer is different and very thin. if you sweep them at high volume you can see the foil heatup at high frequencies and see it is losing tension haha
then go back to normal tension after it cools 🙂
then go back to normal tension after it cools 🙂
I'm really not worried about the heat. The adhesive, a thermosetting rubber, and the polyester are designed for continuous operation not exceeding 130°C.
And I guess, that an EQ of 10dB isn't really that much to worry about as you say.
But, as the EQ is in the digital realm, I cannot boost the HF levels; I must lower the frequencies below by 10dB.
Hopefully I have enough headroom for it in the various components so the SPL will have a decent level in the end.
And I guess, that an EQ of 10dB isn't really that much to worry about as you say.
But, as the EQ is in the digital realm, I cannot boost the HF levels; I must lower the frequencies below by 10dB.
Hopefully I have enough headroom for it in the various components so the SPL will have a decent level in the end.
Mid membrane 14 µm aluminium traces with 56 film (red) and 74 film (purple):
Not much difference in SPL.
THD:
Not much difference here either.
But 3HD shows some difference:
So the 56 film for the mid membrane is the winner.
For the tweeter I used old 6 µm aluminium traces 74 film as reference.
New measurements were made with 14 µm aluminium traces.
SPL:
The 6µm membrane is still the winner.
THD Distortion:
More or less the same.
3HD:
The 56 film has much lower 3HD below 1.3 kHz. Too bad it is outside the tweeter's intended range.
Not much difference in SPL.
THD:
Not much difference here either.
But 3HD shows some difference:
So the 56 film for the mid membrane is the winner.
For the tweeter I used old 6 µm aluminium traces 74 film as reference.
New measurements were made with 14 µm aluminium traces.
SPL:
The 6µm membrane is still the winner.
THD Distortion:
More or less the same.
3HD:
The 56 film has much lower 3HD below 1.3 kHz. Too bad it is outside the tweeter's intended range.
Looks smooth!! Buuuut the range is not 🙁 you have -15 dB on the FR and Ditstortion witch can never be a thing,. there is no such thing as minus 15 db distortions 🙂
by having it -15 to + 105 you get a response that looks insane flat its like insane smoothing. because in dirtortion measurents it might be max 20dB - 105 at max 🙂 else we designed the best tweeter in the world
Regarding the baking temperature and the baking time: I had to change it to 120°C for 30 minutes.
The individuel aluminium traces were "floating around" at the higher temperature (140°C for 20 minutes).
The individuel aluminium traces were "floating around" at the higher temperature (140°C for 20 minutes).
Did the lower baking temperature impact the mylar, or does it feel as stiff as when baked at a higher temperature?
The higher tempertures affected the PET film, it wiggled a bit, so I've thrown them away as they were useless.
Perhaps 120°C is too much on the safe side; I guess that a rabbit hole is coming up (down?)!
When I made AMTs , I used even 160°C for 20 minutes. But that jig was a lot more constraining:
Perhaps 120°C is too much on the safe side; I guess that a rabbit hole is coming up (down?)!
When I made AMTs , I used even 160°C for 20 minutes. But that jig was a lot more constraining:
Was the only problem when baking at 140 degrees that the traces came loose or was there a negative impact on the mylar also? Since my adhesive should handle higher temperatures I'm thinking if I should go with 140 degrees for the baking.
If you monitor the temperatur you should be able to go as high as 160°C.
Do several test with non-cut membranes to get faster evaluations.
Do several test with non-cut membranes to get faster evaluations.
I've re-tested the baking temperatures and times.
I found that 140°C and 10 minutes is sufficient.
Higher temperatures seems to distort the PET.
I found that 140°C and 10 minutes is sufficient.
Higher temperatures seems to distort the PET.
Well, 140°C and 10 minutes was too much.
Two adjacent traces that should be 0.5mm apart weren't after baking, they were actually shorted a couple of cm.
The PET hadn't shrunk; it still the correct width.
But it seems that one trace had slipped down.
I guess baking with the steel cylinder lying down is better, letting gravity work on the flat membrane.
And also lower the temperature to 130°C.
Two adjacent traces that should be 0.5mm apart weren't after baking, they were actually shorted a couple of cm.
The PET hadn't shrunk; it still the correct width.
But it seems that one trace had slipped down.
I guess baking with the steel cylinder lying down is better, letting gravity work on the flat membrane.
And also lower the temperature to 130°C.
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I'm having great trouble making the 2.5m long membranes. The root cause is that the Silhouette Cameo 5 isn't as accurate as I thought.
This is due to the fact that between each 110mm segment, the machine does a re-homing of the tool. That is in the X direction.
This re-homing causes sometimes the cut traces to be off by a fraction of a millimeter but enough to maka weeding difficult, especially for the 0.5mm bare parts.
The reason for having the shorter segments is that otherwise the cuts will be along the whole membrane to and fro and thus gets misaligned in the Y direction.
I can:
Buy a better cutter (that will cost a lot),
Build my own cutter (that will take a long long time),
Make many membranes and select the best ones (that will take some time),
Let someone else make the membranes to my specification (that will be costly and take some time)
Change the membrane layout (that might affect the performance).
Regarding the latter, I can at least for the tweeter membrane change the layout so that the traces are wider than the perfect 3mm.
This might work due to the fact that at the intented frequency range for the tweeter, it doesn't move that much.
At 3kHz, 1/100 movement is required of the movement at 300Hz to get the same Xmax, so it is worth a try:
Middle trace is 8mm instead of 3mm:
With 6µm aluminium it will still be around 6Ω.
For the mid membrane I haven't tested the 56 film without the fillers, so that is worth a try as well.
This is due to the fact that between each 110mm segment, the machine does a re-homing of the tool. That is in the X direction.
This re-homing causes sometimes the cut traces to be off by a fraction of a millimeter but enough to maka weeding difficult, especially for the 0.5mm bare parts.
The reason for having the shorter segments is that otherwise the cuts will be along the whole membrane to and fro and thus gets misaligned in the Y direction.
I can:
Buy a better cutter (that will cost a lot),
Build my own cutter (that will take a long long time),
Make many membranes and select the best ones (that will take some time),
Let someone else make the membranes to my specification (that will be costly and take some time)
Change the membrane layout (that might affect the performance).
Regarding the latter, I can at least for the tweeter membrane change the layout so that the traces are wider than the perfect 3mm.
This might work due to the fact that at the intented frequency range for the tweeter, it doesn't move that much.
At 3kHz, 1/100 movement is required of the movement at 300Hz to get the same Xmax, so it is worth a try:
Middle trace is 8mm instead of 3mm:
With 6µm aluminium it will still be around 6Ω.
For the mid membrane I haven't tested the 56 film without the fillers, so that is worth a try as well.
You need to provide a reference to level of the fundamental in your distortion graphs. Or use % presentation.
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