Makes sense for the most part. But I just don't want or need my tweeters to be producing mid-range frequencies. That's not what I bought them for. I prefer they pump out the highs. The F/R of these is 2500-30,000 Hz. So yes, a 5000 Hz cut-off would be ideal. Sonic is suggesting the PAC #BB-6PR, which have a cut-off frequency of 5600 Hz for 4-ohm tweeters. PERFECT! As most of us know, the human ear only hears frequencies between 20 and 20,000 Hz. So "technically", I wouldn't hear anything from the tweeters anywhere near their 30,000 Hz high note capabilities. But it's also a "coolness factor" to have speakers that go that high, even if only animals will here them. LOL!
I just put in Kenwood 6.5" 3-way speakers in my front doors and rear deck, only to be very unhappy with their high frequencies. In fact, my factory 2-way door speakers that only handled 15 watts max put out better highs than these Kenwoods. It's actually the first time I've been unhappy with any Kenwood speaker. So, I have plans to replace them with Clarion SRG-1622R's, which have a frequency response of 30-30,000 Hz, much broader than the Kenwood KFC-1664S's 35-22,000 Hz. I then plan to buy a pair of Clarion SRQ6933R's for the rear deck. These have a frequency response of 25-35,000 Hz! Unbelievable for a 6x9. I can't find the SRQ series in door speakers.
So, some of you might be scratching your heads and wondering why in the world I even WANT or NEED tweeters. Good question. Simple answer. I just want clearer highs. Anyone can get bone-rattling bass by just throwing a couple cheap subs in a box with an amp. I see it all day long. But when that car is bumpin along or pulls into a parking lot with all the windows down trying to impress everyone, they look awfully ridiculous when you can't hear even the faintest mids or highs because they're running stock speakers off a stock deck, then most likely running some inputs (line level or RCA) into an amp for some subs. I want just the opposite. I want people to walk up and compliment me on how crystal clear my highs sound and ask me what kind of speakers I have (like they did all day with my Stratus stereo).
So, to sum it all up, I don't think I'll worry about reproducing frequencies down between around 2,500 Hz of these tweeters and the 5,600 Hz of the bass blckers out of the tweeters.
Thanks again for everyone's opinion. I might sound crazy but I'm really just crazy for sound. But on THIS car, I have an extremely tight budget, unlike the Stratus. So no subs, no pair of 1,000 watt amps and 1,800 watt sub amp, no optima battery, nothing fancy. Just a simple 4-channel amp powering door and rear deck speakers plus my deck powering some tweeters and I'm going to call it good.