Electrical Crossover and Acoustical Response

[jtrosky]

What speaker could you possibly have, and installed how that you are crossing at 55hz to 750 hz?

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I'm crossing it at those *electrical* values to get an acoustical crossover of 65hz/500hz (LR24) - that was the whole point of this thread - using different electrical crossover points to accomplish the acoustical crossovers that you want. :-)

This is a door-mounted 6x9 midbass speaker though. Yes, I realize that most people don't like to cross that low, but it works for me... These particular speakers actually play down to 40hz pretty well, believe it or not (the Kenwood Excelon KFC-XP6903C component set).

[jtrosky]

Wouldn't shaping the acoustical phase with eq accomplish the same thing if electrical crossovers were just in the wrong spot with each position?

Yes, you could - but like I mentioned, if I crossed them electrically at the same point I actually want them cross acoustically, I would need a huge boost (6dB+) at the crossover area to meet my target curve. By "extending" the electrical crossover, I can get the acoustical crossover that I want without needing any boost.

By changing my electrical crossover point from 500hz/24dB to 725hz/36dB, I don't need to boost this area at all to meet my curve:

[Hillbilly SQ]

I'm crossing it at those *electrical* values to get an acoustical crossover of 65hz/500hz (LR24) - that was the whole point of this thread - using different electrical crossover points to accomplish the acoustical crossovers that you want. :-)

This is a door-mounted 6x9 midbass speaker though. Yes, I realize that most people don't like to cross that low, but it works for me... These particular speakers actually play down to 40hz pretty well, believe it or not (the Kenwood Excelon KFC-XP6903C component set).

My Audiofrog gs690's would hammer quite nice crossed in the 40's or 50's too. Had a preset with them crossed at 40 with all the big midbass cuts to level out the response into the 2000's just to show off. One of the only times I considered not even having a subI had mine at 70hz iirc because they were playing up to 2500 to gb10's but as a dedicated midbass I bed 50hz woulda been fine with enough door treatment.

[jtrosky]

My Audiofrog gs690's would hammer quite nice crossed in the 40's or 50's too. Had a preset with them crossed at 40 with all the big midbass cuts to level out the response into the 2000's just to show off. One of the only times I considered not even having a subI had mine at 70hz iirc because they were playing up to 2500 to gb10's but as a dedicated midbass I bed 50hz woulda been fine with enough door treatment.

Honestly, that is one of the reasons I cross them so low (65hz) - because I don't have a "real" sub - just an 8" self-powered under-seat sub (JBL BassPro SL). So between the 6x9s playing low and the underseat sub, they combine to give me a nice flat response in the subwoofer area - I actually overlap them a little. It's only flat to about 40hz though- falls off quickly after that). So I don't get the deepest bass without a "Real" sub, but I get down to ~40hz at very good levels with what I have. I won't be putting a "real" sub in the trunk. My overall response is in one of the pics I posted above in this thread.

Like I said, it works for me. :-) Some 6x9's can really handle a lot of bass it seems. Believe it or not, even having them play that low, without *any* sound deadening (yet), I still don't hear any rattles while playing music. I'm sure there are some, but when the system is loud enough to cause them, I don't hear any rattles - at least not yet (new car with pretty new audio system - eventually, it will start to rattle, I'm sure). Will deaden the doors once the weather warms up...

[Brego]

Yes, you could - but like I mentioned, if I crossed them electrically at the same point I actually want them cross acoustically, I would need a huge boost (6dB+) at the crossover area to meet my target curve. By "extending" the electrical crossover, I can get the acoustical crossover that I want without needing any boost.

By changing my electrical crossover point from 500hz/24dB to 725hz/36dB, I don't need to boost this area at all to meet my curve:

Could you accomplish the same result if you used 600/12dB instead of 750/36dB? 12dB Xo's gives a more natural sound, and you could reduce the gap in your Xo's to the Speaker Curve...

[SkizeR]

I'm crossing it at those *electrical* values to get an acoustical crossover of 65hz/500hz (LR24) - that was the whole point of this thread - using different electrical crossover points to accomplish the acoustical crossovers that you want. :-)

This is a door-mounted 6x9 midbass speaker though. Yes, I realize that most people don't like to cross that low, but it works for me... These particular speakers actually play down to 40hz pretty well, believe it or not (the Kenwood Excelon KFC-XP6903C component set).

Yeah, no dont do that. See where I said just because the response doesnt say do, doesnt mean they're not being sent to the moon. That's WAY too much boost near a high pass filter

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[jtrosky]

Could you accomplish the same result if you used 600/12dB instead of 750/36dB? 12dB Xo's gives a more natural sound, and you could reduce the gap in your Xo's to the Speaker Curve...

I believe that 600/12dB and 725/36dB crossovers would actually end up almost exactly the same, so it really doesn't matter which one you use. Whether you use 12dB or 36dB slopes really doesn't matter if the end result is the same (which is a 24dB acoustic slope in this case). Again, the *electrical* crossover frequency/slope you use doesn't matter - as long as the acoustic slope ends up where you want it. I wanted a 500hz/24dB crossover in this case - and both 600/12dB and 725/36dB both end up at the same result in this case, for my midbass freq response.

Yeah, no dont do that. See where I said just because the response doesnt say do, doesnt mean they're not being sent to the moon. That's WAY too much boost near a high pass filter

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You lost me on this one - not sure if you quoted the wrong post or what? Don't do what? The whole purpose of me using those "alternate" electrical crossover (725hz/36dB) settings was so that I avoided using any boost near the low-pass filter. I don't use any boost at all near the high-pass filter - I just let the speakers roll off naturally.

[Brego]

.... yeah, SkizeR, you lost me on that one too.....

Are you referring to this statement >>

the only thing that matters about the "electrical crossover" is protecting the speakers from signal that is too low in frequency for them to handle. Just becuase your response reads that a tweeter is crossing over at 2k on the rta, and your crossover in the dsp software shows 1k, those tweeters are still seeing and playing that 1k signal.

That would suggest to me that a 600/12dB works out better than 725/36dB.......

[jrwalte]

I don't think it matters on the high cutoff of a bandpass and Skizer is just referencing a high pass. A speaker can play any higher frequency without damage, it just beams and falls off. But you can damage a speaker if you set the highpass too low for the speaker to handle, even though it is making your acoustical crossover point look better. In a case like this, you should move the acoustical cross over up the freqency range and let the lower 'bigger' speakers play higher.

[jtrosky]

Agreed - that is the only thing I can think of as well... He's talking for speaker protection specifically. In my example, that doesn't apply since I'm talking about a low-pass xover for a midbass speaker.

For my 3.5" coaxials, I actually use the same electrical crossover as the acoustical crossover I want (500hz, 24dB in my case) - I could actually cross over lower if I wanted on those. My issue was only with my one midbass speaker - and using a higher crossover point really helps in that case.

I just didn't understand his post because the post he quoted was talking about the xover for a low-pass xover and he mentioned a high-pass.