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^Lowering the subwoofers frequency^ seems like a reverse psychology approach to the spirit of, "Use your subwoofer to get better midbass"?
 
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Just wanted to say thanks for putting this on here. I was wondering where the midbass went in my car. Crossed it back at 80htz and sloped it at 24db. It's back and I love it.

I now have a bit of a transition problem where I can tell where the sub is kicking in more instead of it all blending. The punch is stronger now than when I used a 12db slope. Wondering if this is a trade off.
 

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Nice video and thanks for taking the time to make it. I was always taught to crossover the sub as high as it could be crossed and then work on the mid bass crossover next. Every car and install can be so different based on so many factors that there is no one size fits all and experimenting always seemed to yield the best results for me. It's always best to let the sub do what it does best, and even at that experimenting with box configurations, placement and phasing takes time to get it just right. Sometimes I will build two or more boxes before I arrive at one that seems to work the best.

I find that letting the sub play loud within it's intended design lets me cross the mid bass speakers higher and allows them to play cleaner and louder and makes the system much more dynamic and enjoyable. I have started builds that have taken over a year to sound decent to me and even at that, I have had some that I have never been happy with. It is the rabbit hole that is high end car audio.
 
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Great topic - thanks for the post and video @ErinH ! I missed this thread last year as I wasn't actively working on a system.

I've been on the struggle bus getting solid mid-bass up front on the 2 Accord Coupes I've owned in the last 7 years. Before the first one in 2014 I owned a GX470 with the Mark Levinson system that had 3-way in the doors with 6x9 woofers with good impact - I never really got the bass I was looking for out of Morel 6.5s after moving to the Accord. Traded that Coupe for an Infiniti G37x that used 10s in the doors for the Bose system - again an impressive output from the front doors.

For my current Accord Coupe, using the same Morels, I started experimenting (great part of DIY) with crossover frequencies - part of this was reading online the markings from the amplifier manufacturer are often not visually correct for the built in crossover frequencies - where I thought I had previously been crossing over around 80 Hz was closer to 55 Hz.

I'm planning on downloading REW soon to use and look for the null you mention in the 50-80Hz range and adjust accordingly. After running 6x9s and 10s in the doors I was convinced I would never have the same output from 6.5s - after moving the crossover frequency (both to 80) and watching this video I have some more work to do!

-Eric
 

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Would you ever have a situation whereby you cross your midbass say at 60hz if not lower and cross your sub higher?

If you have a set of 8’s as midbass you don’t want to really cross your midbass higher as there would be no point to a 8” midbass driver


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Typically you don't need to overlap. So the sub would just play the bottom octave (<60). If you dont have a null issue from the midbass location and they have enough output then you shouldn't need the sub to play the midbass pass band.
 

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I always overlap my subs and my midbasses, and something I've found helpful is to mess with the delays of ONE driver.

For instance, when my two subs and my two midbasses are running with no delay, I have a whopper of a peak at 60Hz, something like ten dB. Obviously, this is a room mode, the four drivers are hitting a room mode.

The "normal" way of fixing this would be to use EQ, which I tried. And it wasn't satisfactory; when you're using a "cut" of ten decibels, it's just going to sound weird, that's a lot of EQ.

So here's what I did instead:

1) 60Hz is 567 centimeters long.
2) Sound travels 34 centimeters in one millisecond
3) 567 divided by 34 is 16.67

So I delayed ONE subwoofer by 4.34 milliseconds.

What this does, is it puts one of the four drivers ninety degrees out of phase with the other three. If it was a "full" 180 degrees out of phase, you would get a perfect null. By delaying it by just 90 degrees, the one of four drivers is about fifty percent out-of-phase, but not 100% out of phase.

The net effect?

The peak at 60Hz disappeared. In other words, a delay of just 90 degrees on one of four drivers was enough constructive interference to completely nullify a peak in the overall response.

I imagine you could do something similar to fill in a null. IE, if you have four drivers playing at 60Hz and you have a dip, you could make one of them 90 degrees out of phase to 'fill in' the dip.

I wouldn't do this 'delay' trick with midbasses, because they cover a wider spectrum. My subs are lowpassed at around 80hz, so the delay that I introduced doesn't have much of an impact at high frequencies. But if I had delayed my midbassed by 4.34 milliseconds, instead of my subs, then there's a possibility that the delay would introduce peaks and dips ABOVE 80hz. For instance, a delay of 90 degrees at 60Hz is a delay of 180 degrees at 120Hz, and that would introduce a null.

I know this post is kinda confusing, and as always, I recommend trial and error and a lot of measurements. My main point is that overlapping your midbasses and your subwoofer can give you some tools that are not available otherwise. For instance, if you only have two drivers playing at 60Hz (your subwoofers) then this trick I describe is not as effective.

One way to visualize the tricks that I am describing, is to learn how cardioid subwoofer arrays work:


 

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I always overlap my subs and my midbasses, and something I've found helpful is to mess with the delays of ONE driver.

For instance, when my two subs and my two midbasses are running with no delay, I have a whopper of a peak at 60Hz, something like ten dB. Obviously, this is a room mode, the four drivers are hitting a room mode.

The "normal" way of fixing this would be to use EQ, which I tried. And it wasn't satisfactory; when you're using a "cut" of ten decibels, it's just going to sound weird, that's a lot of EQ.

So here's what I did instead:

1) 60Hz is 567 centimeters long.
2) Sound travels 34 centimeters in one millisecond
3) 567 divided by 34 is 16.67

So I delayed ONE subwoofer by 4.34 milliseconds.

What this does, is it puts one of the four drivers ninety degrees out of phase with the other three. If it was a "full" 180 degrees out of phase, you would get a perfect null. By delaying it by just 90 degrees, the one of four drivers is about fifty percent out-of-phase, but not 100% out of phase.

The net effect?

The peak at 60Hz disappeared. In other words, a delay of just 90 degrees on one of four drivers was enough constructive interference to completely nullify a peak in the overall response.

I imagine you could do something similar to fill in a null. IE, if you have four drivers playing at 60Hz and you have a dip, you could make one of them 90 degrees out of phase to 'fill in' the dip.

I wouldn't do this 'delay' trick with midbasses, because they cover a wider spectrum. My subs are lowpassed at around 80hz, so the delay that I introduced doesn't have much of an impact at high frequencies. But if I had delayed my midbassed by 4.34 milliseconds, instead of my subs, then there's a possibility that the delay would introduce peaks and dips ABOVE 80hz. For instance, a delay of 90 degrees at 60Hz is a delay of 180 degrees at 120Hz, and that would introduce a null.

I know this post is kinda confusing, and as always, I recommend trial and error and a lot of measurements. My main point is that overlapping your midbasses and your subwoofer can give you some tools that are not available otherwise. For instance, if you only have two drivers playing at 60Hz (your subwoofers) then this trick I describe is not as effective.

One way to visualize the tricks that I am describing, is to learn how cardioid subwoofer arrays work:


So you run your subs at 80hz and midbass at 60hz?


Sent from my iPhone using Tapatalk
 
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