Amp is class D rated at 2-4 ohm load. It does not have a 1 ohm rating.
Speakers are a 2-way for car audio.
To overcome some tweeter shortcomings, with XSim, I designed a better 3rd order tweeter crossover network (crossover design attached). Unfortunately the resistance on the predicted impedance curve appears to drop to about 1.5 ohms at 4 kHz (chart attached). If I understand it correctly, less amplifier load is used to power higher frequencies, therefore I would imagine this not to an issue. However I wanted to run this by the pros here at diyaudio. Will this design overload the amp or shorten its life, or will it be fine?
Speakers are a 2-way for car audio.
To overcome some tweeter shortcomings, with XSim, I designed a better 3rd order tweeter crossover network (crossover design attached). Unfortunately the resistance on the predicted impedance curve appears to drop to about 1.5 ohms at 4 kHz (chart attached). If I understand it correctly, less amplifier load is used to power higher frequencies, therefore I would imagine this not to an issue. However I wanted to run this by the pros here at diyaudio. Will this design overload the amp or shorten its life, or will it be fine?
Attachments
It won't overload it, but you will probably hear a suck out, a drop of actual frequency. XSim uses a theoretically ideal amplifier, with infinite current capacilities. Most amps are not perfect, and almost all amps have a rising output impedance with frequency, so this is definitely not desirable.
Looking at your design, C1 and C3 are swapped. If you are attempting a 3rd order filter, the first one is the smallest, and the second cap is the larger, often by a factor of 3-4.
Next, you may find it useful to use small value resistors on shunting devices, like C2 and L2.
Best,
E
Looking at your design, C1 and C3 are swapped. If you are attempting a 3rd order filter, the first one is the smallest, and the second cap is the larger, often by a factor of 3-4.
Next, you may find it useful to use small value resistors on shunting devices, like C2 and L2.
Best,
E
Thank you. I'm looking to improve an issue with poor tweeter design, to flatten out the pyramid shaped tweeter frequency curve that peaks at 9k with a 20db down valley at 3k. My design greatly improved this, and when I bring up the C1 value to raise the impedance, the pyramid grows back. Take a look at the attached graphs.
My main question is whether this will be a problem in real world conditions, since very little power is used to create higher frequencies.
My main question is whether this will be a problem in real world conditions, since very little power is used to create higher frequencies.
Attachments
Woofer is fine but tweeter crossover is a mess.
Sweeping from a low of less than 2 ohm to a peak of 20 ohm!!!!!
That´s not a crossover but a highly resonant load which your amplifier will not like at all.
Please redesign a new one.
Sweeping from a low of less than 2 ohm to a peak of 20 ohm!!!!!
That´s not a crossover but a highly resonant load which your amplifier will not like at all.
Please redesign a new one.
Adding L-Pad to soften impedance curve
I can add an L-Pad to soften the extremes of the impedance curve without major harm to the frequency response, however it still dips down below 2 ohms. I was not aware that volatility of an impedance curve made any difference on class D amps, only class A.
I can add an L-Pad to soften the extremes of the impedance curve without major harm to the frequency response, however it still dips down below 2 ohms. I was not aware that volatility of an impedance curve made any difference on class D amps, only class A.
Attachments
OEM Values
To give a better picture of the problem, attached is the OEM 6db crossover with frequency and impedance curves. The overlap of the two drivers along the 1.2kHz to 4kHz range combined with the fact component car speakers are non-coincident (2ft from dash mount to door) makes the mids utter mush without any clarity to voice. The deep 20db valley at 2-5kHz takes away any presence. Add the massive exaggeration at 9-11kHz makes treble scratchy with massive sibilance (vocal esses) and you can see why I want to fix this.
I have improved on many crossovers, decades ago with analog equipment and trial and error, currently with the use of software as an aid. Garbage in, garbage out may be the greater issue, but better crossover design has yielded extraordinary results on most occasions.
I am just unfamiliar with the loads on amps and needed a bit of assistance. This is a new issue for me.
FYI, I recently tested 5 old car and home tweeters and almost all exhibited this poor audio quality frequency curve (except for a 30 year old infinity EMIT car tweeter that had a ripped cone and equally old Audex 25mm soft domes. They both were reasonably flat).
To give a better picture of the problem, attached is the OEM 6db crossover with frequency and impedance curves. The overlap of the two drivers along the 1.2kHz to 4kHz range combined with the fact component car speakers are non-coincident (2ft from dash mount to door) makes the mids utter mush without any clarity to voice. The deep 20db valley at 2-5kHz takes away any presence. Add the massive exaggeration at 9-11kHz makes treble scratchy with massive sibilance (vocal esses) and you can see why I want to fix this.
I have improved on many crossovers, decades ago with analog equipment and trial and error, currently with the use of software as an aid. Garbage in, garbage out may be the greater issue, but better crossover design has yielded extraordinary results on most occasions.
I am just unfamiliar with the loads on amps and needed a bit of assistance. This is a new issue for me.
FYI, I recently tested 5 old car and home tweeters and almost all exhibited this poor audio quality frequency curve (except for a 30 year old infinity EMIT car tweeter that had a ripped cone and equally old Audex 25mm soft domes. They both were reasonably flat).
Attachments
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