I had built a pair of 2ways about a month ago but had bought some pre-built crossovers. I have since been tying to learn how to design the xovers myself. By far the most difficult part of the process imo. I think I have it at least close and would like to get some opinions. I'll post a screenshot of the graph and a parts list. Also, there are no resistors in this design but I think I dont need them? I want to cross at around 2500. Anyway, any and all help and/or guidance will be appreciated. I will note that even though the video I watched on how to use this particular program said to use tweeter/woofer when doing a 2way. It wouldnt recognize my woofer unless I used TM. I'm sure its something I'm doing wrong but the results look like it might be done right?
WOOFER TWEETER
Ind: 0.76 Cap: 13.48
Cap: 10.76 Ind:0.87
WOOFER TWEETER
Ind: 0.76 Cap: 13.48
Cap: 10.76 Ind:0.87
Hello!
There is an overlaping between 1.5kHz and 3kHz which must be removed.
This is causing a +5dB bump between 1kHz and 4kHz as you can see in the black line.
You can either try a Linkwitz-Riley aligment for your 2nd order crossover or cross at different frequencies to separate a bit these two speakers (woofer a bit lower and tweeter a bit higher).
This online calculator might help out as a starting point:
https://www.diyaudioandvideo.com/Calculator/SpeakerCrossover/
There is an overlaping between 1.5kHz and 3kHz which must be removed.
This is causing a +5dB bump between 1kHz and 4kHz as you can see in the black line.
You can either try a Linkwitz-Riley aligment for your 2nd order crossover or cross at different frequencies to separate a bit these two speakers (woofer a bit lower and tweeter a bit higher).
This online calculator might help out as a starting point:
https://www.diyaudioandvideo.com/Calculator/SpeakerCrossover/
This is what i came up with by switching to Linkwitz and tweaking the inductors and caps. Better right?
Better.
Your scale range is large. We only need around 30dB below the standard level and maybe 6 above.
Have you included baffle effects?
Your scale range is large. We only need around 30dB below the standard level and maybe 6 above.
Have you included baffle effects?
You need your own measurements, but for a WAG starting point, a 2mH coil, and 10uf cap on the woofer.
Pad the tweeter using a resistor across the tweeter leads, and one in series, at the tweeter, ie after the x-over.
For tweeter x-over, I'd start with a 8uf cap, and .4mH coil, and then adjust the cap, leaving the .4mH.
Make adjustments to get both drivers 6dB down at about 2.5k.
I have not. Forgive my ignorance but how will it make it better? The black line is fairly straight. Also, I'm not seeing a section in the program to include it. Is there another way of figuring it? Would you have a link to a good tutorial. I can Google search but if you know of a good one that could help I'd appreciate it.
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The baffle step is the directivity of the box, and it can be detrimental to balance. Here's a post describing it - https://www.diyaudio.com/community/...overs-without-measurement.189847/post-2587232
It is easier if you can simulate or measure, however the quickest way to compensate is to guess the effects. There are a few different baffle diffraction software tools that are sufficiently accurate to make a positive difference. The preferred way is to measure it.
It is easier if you can simulate or measure, however the quickest way to compensate is to guess the effects. There are a few different baffle diffraction software tools that are sufficiently accurate to make a positive difference. The preferred way is to measure it.
From my very limited understanding, the baffle step loss happens around 3-400hz depending on baffle width (thinner the box, the higher it is) and slopes down to about -6dB at 50hz. The issue is that most manufacturer data is measured on a large baffle so shows no or little baffle step loss therefore having a nice flat frequency response using manufacture data will have a lot less bass (sub 400hz) in reality. This all assumes that the speaker is designed to be used a little way off the wall behind (0.5m to front baffle).
So, as a very rough approximation you can design to have rising frequency response form 4-600hz rising to about +6dB at 50Hz. However, if you are going to use the speakers near to a wall then you will then get boundary boost which may offset the baffle step loss so designing flat may be OK.
If you measure your driver in the box you have designed then the baffle step loss is baked into the curve and you can then design form there to flat if that is what you want.
For info, this is typically why the sensitivity of most speakers designed with baffle step loss included in them is about 3-6dB less than the the raw woofer driver response.
here is a quick illustration -
near field (similar to large baffle response of a woofer)
Now with 400hz baffle step loss applied
overlaid
So, as a very rough approximation you can design to have rising frequency response form 4-600hz rising to about +6dB at 50Hz. However, if you are going to use the speakers near to a wall then you will then get boundary boost which may offset the baffle step loss so designing flat may be OK.
If you measure your driver in the box you have designed then the baffle step loss is baked into the curve and you can then design form there to flat if that is what you want.
For info, this is typically why the sensitivity of most speakers designed with baffle step loss included in them is about 3-6dB less than the the raw woofer driver response.
here is a quick illustration -
near field (similar to large baffle response of a woofer)
Now with 400hz baffle step loss applied
overlaid
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Then you filter the green response to make a speaker response at about 82dB. Usually takes about a 2mH coil, if the woofer is 8 ohm. ( 2mH is a good starting point. )
Try increasing the coil until the woofer response at 1k is at 85dB. The response at 100hz will not change. Continue to roll-off the woofer until it is down to about 74dB at your desired x-over frequency. Then adjust the tweeter filter to match.
Yes, so what the box loses, the wall finds.
Usually it combines in a rough way due to the delayed wall reflections being responsible for comb filtering. On top of that, the higher baffle step frequencies may sound delayed.
So to suggest that walls affect the level of compensation would be a case of being overly polite in a difficult situation. When baffle step occurs, room placement becomes important in it's own right. You can then measure your own in room compensation level needs or, you can simulate them in room before you go.