[Toowonphyve]

So if I understand correctly, for each -6db order slope that a 90 degree phase shift is introduced. That's why -24db Linkwitz slopes are often used because they shift phase 360 degrees, effectively placing the signals back in phase. So I instinctively chose -24db LR Crossovers between my Mids and Tweeters in my 2way active setup. One thing I didn't take into consideration though is the -6db "bass blocker" capacitor that I have installed inline on my tweeters for protection from the stupid turn-on pop I have since installing my Dayton DSP-408 (another subject for another thread).

So my question is, how should this -6db bass blocker on the tweeters be accounted for (if at all)? Should I be using a -18db High Pass on my tweeter instead of the -24db? What about the Lo Pass for the Mids? Should that stay at -24db?

The thing that made me consider this is that I have a pretty substantial dip that spans over an octave right around my mid/ tweet crossover point. However it's not a steep narrow dip like I would expect from a phase issue. Its actually a pretty smooth drop that drops about -10db somewhere in the neighborhood of 1.5k and then gradually rises back around 3k (sorry I don't have my measurements open in front of me).

Thanks in advance for any helpful insight

 

[SkizeR]

each 6db slope introduces 45 degrees phase shift, but when combining them, it results in a 90-degree phase shift. for "bass blockers" you should be making sure the crossover of the bass blocker is well below your intended crossover point though. example.. if you intend on crossing a tweeter at 2.5k, i'd aim for a crossover point of that capacitor of 1k or lower. If you do that, its nothing to worry about.

 

[jdunk54nl]

For 1khz or lower you would use a capacitor around 55-65 micro farads (that is about 700hz-600hz)

 

[SkizeR]

i keep 47uf caps in stock at the shop and is what i use on every build.

 

[GEM592]

Shouldn't really need them. The idea that you should even want them originates from very old guard car audio mythology, the roots of which are specious at best.

 

[SkizeR]

Shouldn't really need them. The idea that you should even want them originates from very old guard car audio mythology, the roots of which are specious at best.

and this is advice you should 100% ignore.

Its like saying you shouldnt wear a seat belt because you "shouldnt" get into an accident. caps are used to protect from mistakes or unpredictable happenings, which happens to all of us.

 

[GEM592]

and this is advice you should 100% ignore.

Its like saying you shouldnt wear a seat belt because you "shouldnt" get into an accident. caps are used to protect from mistakes or unpredictable happenings, which happens to all of us.

You know that is just fine. Don't listen to one ****ing thing I say.

 

[SHAGGS]

The reason to use them is to protect against unintended full range signal from being sent to the tweets.
That's why setting them well below your intended crossover freq, will only come into play if there is an anomaly or mistake with the DSP.
It's like insurance. You shouldn't need it, but if you do, it's there to save your ass.

 

[SkizeR]

The reason to use them is to protect against unintended full range signal from being sent to the tweets.

will also protect from DC offset and equipment failure.

 

[GEM592]

Yes, **** me quite thoroughly. That band-aid can indeed cure a thousand cuts. Carry on.

 

[ToNasty]

Ive been looking into this as well. Ill be crossing my tweeters at 4-4.5k. So i figure a 15uf would be perfect

 

[GEM592]

Ive been looking into this as well. Ill be crossing my tweeters at 4-4.5k. So i figure a 15uf would be perfect

Wow they must really be special.

 

[ToNasty]

Wow they must really be special.

What do you mean

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[GEM592]

Ive been looking into this as well. Ill be crossing my tweeters at 4-4.5k. So i figure a 15uf would be perfect

Crossing that low you really need to guard those cherrys.

 

[ToNasty]

Crossing that low you really need to guard those cherrys.

Low? 4k-4.5k is low?

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[GEM592]

Low? 4k-4.5k is low?

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Better put some caps on there to make sure, right?

 

[GEM592]

Low? 4k-4.5k is low?

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I admit I was making fun of you. Tweet crossover point is only ever that high in a bad 2 way setup. At that point a cap ain't going to help too much.

 

[ToNasty]

I admit I was making fun of you. Tweet crossover point is only ever that high in a bad 2 way setup. At that point a cap ain't going to help too much.

Ahh ok. Im doing 3 way. Or else id cross about 2200-2400

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[GEM592]

Ahh ok. Im doing 3 way. Or else id cross about 2200-2400

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Well given all this wisdom I don't know why you need to add first order passives into the mix, but I guess you're worried about other problems. Whatever gets you to sleep at night.

 

[ToNasty]

Well given all this wisdom I don't know why you need to add first order passives into the mix, but I guess you're worried about other problems. Whatever gets you to sleep at night.

In totally lost on what youre saying. The 15uf is just tweeter protection.

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