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Discussion Starter #1
me thinks the title speaks (reads?) for itself. i've seen in various threads that nearly everyone recommends, for example, running their mids/midbass as low as possible with the steepest slope as well as the subs as high with the steep slopes too.

is it because the usage of a shallower slope is more or less unpredictable how a driver will perform due to a "non-brick wall" type slope; >36db as i've read.

is it a phase thing? or something else that i can't remember since American Dad distracted me?
 

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well if you want to run a speaker up to a point and have it fall off like rock, then a steep slope will work nicely. depending on the speaker, i like a shallower slope. like the top end of a midbass, if you cross it at 2khz, I like to use 12dB/oct. I think it sounds more natural. the top end of a sub, on the otherhand, I like to use 24dB. I dont like midbass in my subs, it makes the bass too directional, so a fast slope is better, IMHO.

if you use passives, then yes, phase is an issue. at the tuning point you will see a 90° shift for every 6dB/oct your crossover is designed for. with carefull design, you can eliminate this by swapping the speaker wires 180° (in other words, if you use a 12dB/oct on your tweeters and nothing on the midrange, swap one of them around)
 

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Discussion Starter #3
i was sort of thinking about 6db/octave slopes.
 

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I think it's also that using such shallow slopes you're going to have a big range of the same frequencies being reproduced from multiple drivers at once.
 

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Discussion Starter #5
well obviously you wouldn't want the XO points as close as you would have with more conventional points, but is there no place for them?
 

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A simplistic way of putting it is less driver interaction/overlap with the steeper slope. This addresses many of the problems that occur in the average car install.

Eric
 

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I chose a 6 dB/octave slope on my front channel high pass filter. I have my Center Stage system and 2 pairs of tweeters on those channels. The Center Stage system can be crossed over as low as 150 Hz with the included blending module, and the tweeters are handled by passive crossovers. My head unit only goes down to 1 kHz on the front channels. I use the most gentle slope because I want that extra output below 1 kHz.
 

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I'm running active with a CDA-9833 and SPX-177R's for my front soundstage. Because of space constraints (BMW Z3 Roadster) I have my speakers in the stock locations, mids in the kick panels and tweets in the doors, with no real room for a custom kick panel.

Just for the sake of experimentation I followed the installation guidelines for setting up the passive crossovers and although I haven't had a chance to tweak it yet, I like the sound so far.

Their recommended settings were with the mids set flat on the top-end and the tweets with an 18dB slope at 2.5K. It seems to have helped a lot with getting the upper-midrange out of the footwells. I am seriously off-axis on the mids...
 

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I'm considering running my new pair of Massive CK6V mids off their 18 db @ (maybe 2.5K?) passive Xover with stock tweeters off the HU, which have a 6 db cap at probably much higher than that.

How does phase work for a 18 db passive and then a 6 db cap?
 

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A simplistic way of putting it is less driver interaction/overlap with the steeper slope. This addresses many of the problems that occur in the average car install.
Eric
^^ That is the simplest way of putting it. Good sound is about tonality and imaging. Both would take a hit to varying degrees, with shallow slopes.
 

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Discussion Starter #13
i do suppose the rather simplistic way mr. stevens put it to make sense. i was messing around with the 6.5" component mid and 100hz with a 6db slope didn't sound bad.

i've decided to try and not run my 6.5" as low as i can since from what i've read, and after thinking about it somewhat logically, there is almost no way a speaker that small can play those notes with the same authority as a sub albeit with bit of tuning. in the past i was able to have them at 63 and 80hz with a 18db slope with little to no issues.
i figure if i can run the subs a bit higher, either through the use of the steepest slope i can from the HU, 18db, or a more shallow slope at a lower frequency, then i would be able to set the HPF for the mids, while attempting to keep the same slope as the sub, a bit higher and not have to worry about stressing them out as much and theoretically prolonging their life.
 

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well if you want to run a speaker up to a point and have it fall off like rock, then a steep slope will work nicely. depending on the speaker, i like a shallower slope. like the top end of a midbass, if you cross it at 2khz, I like to use 12dB/oct. I think it sounds more natural. the top end of a sub, on the otherhand, I like to use 24dB. I dont like midbass in my subs, it makes the bass too directional, so a fast slope is better, IMHO.

if you use passives, then yes, phase is an issue. at the tuning point you will see a 90° shift for every 6dB/oct your crossover is designed for. with carefull design, you can eliminate this by swapping the speaker wires 180° (in other words, if you use a 12dB/oct on your tweeters and nothing on the midrange, swap one of them around)
Phase shift occurs exactly the same in active filters, too.

I love me some shallow slopes on the midbasses - I tend to combine a shallow slope with a giant EQ suckout to hasten the roll-off at frequencies other than the strict octave poles. Call it a 'knee' or inverse Linkwitz Transform (haha). Very smooth phase transitions and then an off-the-cliff dip where I can't hear the massive phase shift anyway. This is a drastic departure from my old "steep and low" recommendation from the late 1990s. DSP makes it soooo much simpler. :)
 

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You need steep slopes and you need to eq each driver ~ an octave above and below the xover point. Beyond that, octave you need the eq to drop everything else like a rock. Attached is my eq setting for the far mid and tweet, with both drivers cut at 3khz on a 24db slope. 24db is the steepest that the bit ten goes.
 

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Discussion Starter #16
that bit ten is the next thing on my list to acquire. that is damn near exactly what i was thinking about trying out once i got the thing. does doing that sort of thing do any funky stuff to the phase that so many are obsessively worried aboot?

your pics are somewhat small, but basically you're saying that if you high-pass your mid at [email protected] then at 40 and below you are dropping all the way down? i must admit when i was planning that, i was going to go with .5 octave. so crossed at 80 i would drop everything from 60 and below.
 

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You need steep slopes and you need to eq each driver ~
Oh yeah? Why's that?

It all depends on the drivers & the mounting;)

Talk to an old school home audio purist & ask them about steep xover slopes lol

I'm not saying I totally agree with how some of those old guys think but, I do also think a large bit of the crossover slopes being offered are more for advertising than sound quality.
 

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There is no best slope as all depend on driver response, placement, separation, summing, phase and points. When it comes to car audio, all is affected by driver placement & listening position so the best you can do is utilize a competent dsp that will allow total control of slopes, points, phase, and t/a then experiment from there. I've had installs where each slope were utilized at one time or another and performed well enough to leave it be.

However, there are some old school type gurus that are competent in designing/installing with minimal added outboard electronics (eq & passives), but that seems to be an art form that is just about lost.
 

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Oh yeah? Why's that?

It all depends on the drivers & the mounting;)

Talk to an old school home audio purist & ask them about steep xover slopes lol

I'm not saying I totally agree with how some of those old guys think but, I do also think a large bit of the crossover slopes being offered are more for advertising than sound quality.
Two reasons.

1. I don't suffer from 'old school' hangovers. The best sq car from 15 years ago vs the best sq car today. Which one would win and why?

2. If you're in the car audio hobby, you would do well to ignore almost everything the home audio 'purists' say. Old school or new.
 

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To be honest old school vs new is an beat down argument that is fairly pointless. Both eras have pros & cons, but many will agree that some of the best gear occurred during previous decades and is well sought out still today. The point is that obviously certain ideals were done right back then including simple passives and shallow slopes. The difference is now more add on complex dsp is available that can rend installers rather lazy in creativity. Some of the best setups I've ever heard were simple Rockford amps running tri-mode (front stage & subs), all passives. How many would be willing to try that now? Nowadays everyone and their moms wants to use expensive add on electronics rather than keeping things simple besides a wide band eq.

As far as who would win? On a given budget and level playing field, it would be hard pressed to say that new school could compete for the same amount of x dollars. DSP has it's advantages, but is expensive!! For the same money for a versatile dsp, one could use other better components.
 
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