Gap in x-overs for mid & high. Also, bringing front stage up?

[bikinpunk 10+ year member]

Saw a thread in DIYMA that got me thinking. I noticed alot of people left a large gap between mid & highs.

I never thought about having such a large gap b/t high & mid for the reason of not having to use the P-EQ in that range. Could someone explain a little more about how this works, and maybe suggest what settings I should try to get me started? I suppose you all are saying that instead of wasting a P-EQ band on the 2.6khz range you drop the x-over for mid down to say 2khz or lower and play with the P-EQ there?

Another issue is here lately it seems my music is pulled away from me, especially the vocals. I honestly don't know if it has anything to do with the heat since we've gotten near 80 the past couple days or if I've just not noticed it before. I notice, though, when I drop the tweeter down to about 2.6khz or right around there it seems to pull the soundstage forward more (to me). T/C doesn't really help solve this problem. I used Alpine's T/C JAVA program to get the values and even tweaked a tad from there to get it to where it is now.

My current settings:

X-Over

sub: 28/24db. 80/18db.

mid: 71/18db. 2.6khz/18db.

high: 2.6khz/24db. off

P-EQ:

Band Level Q

71hz -1 0.5

300hz +2 1

2.2khz -1 0.5

7.1khz +2 0.5

18khz 1 0.5

^Sorry for the format...I can't get the spaces to work right in the above. Hopefully you can make out what it is.

In all honesty the "Q" only makes my music sound more far fetched. I understand that the higher the value the wider the band plays, but I just don't really like anything above 1 at the most. If I'm not right on what this does, please feel free to clue me in.

Click to read more...

 

[JimJ 5,000+ posts]

The "gap" is there because you need to take the slopes into account. Sometimes crossing over too "closely" can give you a nasty peak at the crossover point.

 

[bikinpunk 10+ year member]

The "gap" is there because you need to take the slopes into account. Sometimes crossing over too "closely" can give you a nasty peak at the crossover point.

I never thought about that because of the graphs I've seen of x-overs. They always show them on the same level, and it seems that even though the slopes intersect, the actual point at which they're crossed over won't. I wish I had a graph to explain what I'm talking about, but what I'm asking is: Do the points truly come into contact with each other at the same response level? I thought they died off before that happened and the point intersected at say -3db?

I need to find that site that's dedicated to electrical/car audio stuff. I believe there's a graph there that shows what I'm asking.

 

[helotaxi 5,000+ posts]

I never thought about that because of the graphs I've seen of x-overs. They always show them on the same level, and it seems that even though the slopes intersect, the actual point at which they're crossed over won't. I wish I had a graph to explain what I'm talking about, but what I'm asking is: Do the points truly come into contact with each other at the same response level? I thought they died off before that happened and the point intersected at say -3db?
I need to find that site that's dedicated to electrical/car audio stuff. I believe there's a graph there that shows what I'm asking.

Technically speaking the "crossover" point is defined as the freq at which the drivers are at the same level in relation to reference. That level could be at -3dB which would be both the low an highpass filter set to the same freq, something closer to reference for a slightly overlapped filters or something more attenuated for underlapped filters. For example if you had two filters with the same slope, the mid point between the different -3dB points would be the crossover freq. As Jim mentioned, with 2 filters with the same freq set there will be a response bump centered on that frequency. If you space the filter points apart equally on either side of the crossover freq you can level out that bump.

 

[thch 10+ year member]

the issue is that, at the point of crossover, even though power to each speaker is reduced, the speakers are working together, and can provide a net gain.

this is where the Linkwitz Riley filters come into play. By placing the speakers near each other, it can be safely assumed that at the crossover point, the system would normally have a peak. by setting a gap (or by defining the crossover point as -6dB down instead of -3dB), the speakers can acoustically sum to flat, even though they do not electrically sum flat.