@ross51681
Good on you for trying to learn the right way to design these projects ( even if it's somewhat after the fact ). Many of us appreciate that effort!
Having said that, you'll never obtain an accurate simulation if you don't enter into the prediction software good data ( both FR and Impedance ).
I downloaded ( and reviewed ) both of your posted .dxo files and they both have ( career ) limiting shortcomings.
Here's a snap-shot of the first showing 3 Xsim data windows. Can you spot your error ( meaning, the most egregious )??
FYI, REW can capture accurate impedance curves ( which can then be exported as .zma files ) for use in simulation software.
I'd suggest looking into building the necessary adapter ( see REWs help file, or you might simply just buy DATS v3 from Parts Express > assuming you have a PC to run it ).
🙂
Good on you for trying to learn the right way to design these projects ( even if it's somewhat after the fact ). Many of us appreciate that effort!
Having said that, you'll never obtain an accurate simulation if you don't enter into the prediction software good data ( both FR and Impedance ).
I downloaded ( and reviewed ) both of your posted .dxo files and they both have ( career ) limiting shortcomings.
Here's a snap-shot of the first showing 3 Xsim data windows. Can you spot your error ( meaning, the most egregious )??
FYI, REW can capture accurate impedance curves ( which can then be exported as .zma files ) for use in simulation software.
I'd suggest looking into building the necessary adapter ( see REWs help file, or you might simply just buy DATS v3 from Parts Express > assuming you have a PC to run it ).
🙂
Yes thank you! I have since gotten a DATS and a measurement mic 🙂 I have to admit I do not see the error though in the above image...what is it?
THank you I will review this.
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Ahh, good.
Can you please post 2 updated impedance files ( taken in-situ )?
Thanks 🙂
EDIT: The error is using a woofers impedance file ( curve ) in place of one from your PRV driver.
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Ok here are my frd and zma files. I have also included a couple xsim designs...the fourth order xo @1100 seems best to me as far as phase and flat response goes.. But if I need to xo higher for off axis reasons I tried those as well.
@ross51681
Thanks very much!!
Are your response curves done with REW and a USB microphone??
If so, can you please post the .mdat file ( you might need to zip it first ).
( - I'd like to check signal polarities , etc. )
Thanks 🙂
Thanks very much!!
Are your response curves done with REW and a USB microphone??
If so, can you please post the .mdat file ( you might need to zip it first ).
( - I'd like to check signal polarities , etc. )
Thanks 🙂
That 1th order crossover has a big fault that can short your amplifier, the impendance goes to low. I made also one from the same specs (i took the project and redid it). This circuit stays above 4R so the amp won't short, it's also phase aligned as good as i could (not perfect, but very close). I included the project this time (i forgot last time).
Thanks! So here is the impedance from my fourth order...this goes too low? I figured the dip in the HF range didn't matter...am I wrong?
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Wow ok...I figured since it was such a high frequency it didn't matter. Thanks for the input!
After dinner i took another look at it and made it a bit better in the treble. (i was bored).
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It matter less than with bass, but it still can kill your amp. Especially hifi amps are not made for such low load. Some car amps may be able to drive a 2ohm load, but those are not the most hifi ones, the do that to give a lot of watt from a car battery (with relative low voltage), not to sound good.
@ross51681
I think I'll comment a bit more later today ( or tomorrow ) but for now your REW files show a few things ( that'll prevent you from getting accurate simulations ).
Not in any order of severity;
1) The horn driver file ( full impulse ) shows that it has a flipped ( negative ) polarity.
2) Both files have had their impulses "zeroed" within REW > therefore, there's no "time-of-flight//distance info" baked into their respective frd exports > therefore one must enter into XSim an offset that represents the distance between the two drivers respective Acoustic Centers. So far, I don't see anyone here ( within this thread ) adding that offset into their XSim efforts.
3) The impedance files used for these simulations should be ones created once the drivers are mounted onto the enclosure ( +/or horn/driver mounted onto its horn/waveguide or coax woofer ).
- It's clear ( to my eyes ) the woofers impedance curve ( utilized here ) doesn't come from a Bass Reflex box ( iow, it might be the "raw" woofer >> no box ).
🙂
I think I'll comment a bit more later today ( or tomorrow ) but for now your REW files show a few things ( that'll prevent you from getting accurate simulations ).
Not in any order of severity;
1) The horn driver file ( full impulse ) shows that it has a flipped ( negative ) polarity.
2) Both files have had their impulses "zeroed" within REW > therefore, there's no "time-of-flight//distance info" baked into their respective frd exports > therefore one must enter into XSim an offset that represents the distance between the two drivers respective Acoustic Centers. So far, I don't see anyone here ( within this thread ) adding that offset into their XSim efforts.
3) The impedance files used for these simulations should be ones created once the drivers are mounted onto the enclosure ( +/or horn/driver mounted onto its horn/waveguide or coax woofer ).
- It's clear ( to my eyes ) the woofers impedance curve ( utilized here ) doesn't come from a Bass Reflex box ( iow, it might be the "raw" woofer >> no box ).
🙂
1. Yes I was getting strange dips in my far field measurements so I reversed the polarity (it didn't help the issue) and the results seemed exactly the same to me. Do I need to redo it?
2. Where is this done in xsim?
3. Yes they were not mounted. My leads from the DATS are only so long...will it mess with the measurement to hook the test leads to speaker wire hooked to the drivers?
In the way you mean it, you are correct. However amps can be susceptible to noise at higher frequencies, and how they are designed at frequencies beyond the audio spectrum is a major consideration. While most amps will have protections in place, designing your load to fall to a short at higher frequencies is not good practice.