Bluetooth Amp Recommendations

[SSTJ]

Learned a lot from this thread. Starting this one to be more specific to my setup:

• I have a factory head unit and I want to stick with it. Not interested in aftermarket head units.
• I have 6.5 inch coaxial Polks in the sound bar.
• I have 5.25 inch coaxial Polks in the dash.
• I have a self-powered sub (PS-8) under driver’s seat.
• I hope to add tweeters to A-pillars or top of the dash.

If I plan on adding tweeters, does that mean I need a six channel amp? Or can those be wired to the same channel as my dash 5.25 speakers without much loss of quality?

If I keep the PS-8 as the sub, how should I get the signal to it? Do I need an extra channel on the amp, or should I just steal a signal from the back of the head unit? (It's factory, so has no dedicated output for a sub.)

I would like the amp to have Bluetooth capability, and some kind of remote controls (wired is fine). I would also like it to fit under the steering column.

Any recommendations appreciated!

---

Conclusions: Based on the helpful replies below, here's what I'm thinking:

• I will look for a 4-channel amp. Preferably with bluetooth, or one for which I can add a Bluetooth receiver as input.
• I will look for a set of component 5.25" speakers, putting the woofer in the dash and the tweeter on top of the dash.

 

[williambmac]

Ask @skrelnik. He is the most knowledgeable when it comes to audio

 

[kmbarreiros]

You are not really going to find an amp to do everything you are asking.
But here is the closest I could find, Has bluetooth, a remote, and only 2 channel.
It is more designed to be used by itself.
AK370-400W-DC-12V-or-AC-220V-Remote-Control-bluetooth-HiFi-Home-car-Stereo-Amplifier-Music-Receiver-FM-Radio-20Hz-20KHz

This is cheap china stuff so the power ratings are probably extremely inflated.

You really should just look into an aftermarket head unit that has front, rear/sub preouts and bluetooth built in.
Get replacement speakers then if you need more power get amps for those speakers.
Most good quality head units can power the door and sound bar speakers just fine.

 

[112dB]

Have you already purchased the gear listed, or are you in the planning stage? Whats the purpose of the stock head unit? are you planning to use it or is it just there to deter theft?

if you want to fade between the front/rear you'll need a 4 channel amp. (If you don't, you can wire your front and rears for each side to one channel, but there are caveats there...) Go with coaxials (tweeter mounted on the driver) in the overhead/soundbar and a pair of components ( separate 5.25 and tweeter ) for the front dash speakers.

You could wire in an additional set of tweeters, but to do it properly would be too much of a hassle and the sound would still likely be horrible.

As for the amp, you can also use something like the audiocontrol ACX-BT1 to add a bluetooth input to any amp. ( https://www.audiocontrol.com/car-audio/accessories/acx-bt1/ ) I have one. It was great. it died, but AC is sending me a replacement. If you go this route, you'll need a 12v+ turn on (usually a blue wire). the ACX-BT1 has this, but others such as the JL Audio Marine one does not.

Be aware of sensitivity ratings - speakers with 90+ db sensitivity will give you more output than those with 85-86 db. It's a noticeable difference, and the higher sensitivity means you can get away with using a less powerful amp.

https://www.crutchfield.com/p_530ST410DB/Soundstream-ST4-1000DB.html?tp=115 <- that may work for you but if I was going to do a 'headless' stereo, I'd probably use the ACX-BT-1 and then pick out a 4 channel amp to go with it. Then again, the simplicity of having the BT built in is a plus. FYI - I like crutchfield because I live in a small little town and get grumpy if I have to drive more than 7 miles and the nearest 'real' stereo shop is ~50 miles away.

I mounted my amp under my steering wheel. more details here: https://wranglertjforum.com/threads/112dbs-2002-sahara-stereo-install-saga.36035/

 

[kmbarreiros]

What he said is really what you should do. I just didn't feel like writing that much.
That last link is a really nice setup.

 

[SouthernLJ]

If you're planning on running tweeters, you might as well go with a component set. It comes with it's own crossover. You just need to apply power to the crossover. The crossover will divvy up the power between the mid and tweeter, as well as send them the correct frequencies. I run 6.5" Polk MM1's. They're marine rated. By going with a component set, you use two channels to power 4 speakers. If you did want run additional speakers, this would free up 2 channels of a 4 channel amp.

Most audio folks will tell you that all you need is a component set. This was my case. I went from completely stock stereo, to new head unit with Kicker indash speakers, to kicker indash speakers as well as Kicker sound bar speakers. When I got the component set and amp, I pulled all of the exists coaxial speakers out. I mounted the mids in the roll bar pods (The pods were layered up with Dynamat and stuffed with polyfill) and the tweeters were flush mounted in the dash. There are no in-dash speakers. I'm happy with the setup.

I also mounted an amp under the steering column. I mounted it to a cheap, plastic cutting board. It also had room to mount the component set crossovers, as well as the terminal blocks for the dual amp kit that takes the 4ga main run and splits it into two 8ga runs. The other 8 gauge run goes to a micro sub amp mounted in a locking Smittybilt glovebox. I run a SSA Audio 12" Demon for a sub.

One thing to note: Don't expect to be wowed by the midbass, especially if you are running co-ax speakers. The ones in the dash are, for all intents and purposes, ran free-air. Basically what you would get if you took a set of speakers and set them on a work bench and powered them up. Mounting the mids from the component set in the roll bar pod improved this a little bit. While you do have somewhat of an enclosure for them, there is little airspace and that affects mid-bass response. I had a 94 Toyota Pickup that I dynamated the whole door and the 6.5" mid from my Alpine Type-R sounded freakin amazing. That's because of how much airspace the speakers got. It's just not the same in the Jeep pods.

I have some pics I can post if you're interested.

 

[SSTJ]

Have you already purchased the gear listed, or are you in the planning stage? Whats the purpose of the stock head unit? are you planning to use it or is it just there to deter theft?

if you want to fade between the front/rear you'll need a 4 channel amp. (If you don't, you can wire your front and rears for each side to one channel, but there are caveats there...) Go with coaxials (tweeter mounted on the driver) in the overhead/soundbar and a pair of components ( separate 5.25 and tweeter ) for the front dash speakers.

You could wire in an additional set of tweeters, but to do it properly would be too much of a hassle and the sound would still likely be horrible.

As for the amp, you can also use something like the audiocontrol ACX-BT1 to add a bluetooth input to any amp. ( https://www.audiocontrol.com/car-audio/accessories/acx-bt1/ ) I have one. It was great. it died, but AC is sending me a replacement. If you go this route, you'll need a 12v+ turn on (usually a blue wire). the ACX-BT1 has this, but others such as the JL Audio Marine one does not.

Be aware of sensitivity ratings - speakers with 90+ db sensitivity will give you more output than those with 85-86 db. It's a noticeable difference, and the higher sensitivity means you can get away with using a less powerful amp.

https://www.crutchfield.com/p_530ST410DB/Soundstream-ST4-1000DB.html?tp=115 <- that may work for you but if I was going to do a 'headless' stereo, I'd probably use the ACX-BT-1 and then pick out a 4 channel amp to go with it. Then again, the simplicity of having the BT built in is a plus. FYI - I like crutchfield because I live in a small little town and get grumpy if I have to drive more than 7 miles and the nearest 'real' stereo shop is ~50 miles away.

I mounted my amp under my steering wheel. more details here: https://wranglertjforum.com/threads/112dbs-2002-sahara-stereo-install-saga.36035/

Hey, thanks for all of this. Really helpful.

I’m sticking with the stock head unit out of preference. My only problems with the stock head unit are the low power and lack of Bluetooth. A Bluetooth amp seems like a simple way to fix that. Or, sure, I like your idea of simply adding Bluetooth input any other amp.

Can you tell me more about why it would be difficult to install tweeters the right way? That’s what’s behind my question about whether I would need a six channel amp, or whether tweeters can be wired with a four channel amp. I do already have the Polk speakers in the sound bar and the dash. It’s only the tweeters that I haven’t done yet.

 

[SSTJ]

If you're planning on running tweeters, you might as well go with a component set. It comes with it's own crossover. You just need to apply power to the crossover. The crossover will divvy up the power between the mid and tweeter, as well as send them the correct frequencies. I run 6.5" Polk MM1's. They're marine rated. By going with a component set, you use two channels to power 4 speakers. If you did want run additional speakers, this would free up 2 channels of a 4 channel amp.

Most audio folks will tell you that all you need is a component set. This was my case. I went from completely stock stereo, to new head unit with Kicker indash speakers, to kicker indash speakers as well as Kicker sound bar speakers. When I got the component set and amp, I pulled all of the exists coaxial speakers out. I mounted the mids in the roll bar pods (The pods were layered up with Dynamat and stuffed with polyfill) and the tweeters were flush mounted in the dash. There are no in-dash speakers. I'm happy with the setup.

I also mounted an amp under the steering column. I mounted it to a cheap, plastic cutting board. It also had room to mount the component set crossovers, as well as the terminal blocks for the dual amp kit that takes the 4ga main run and splits it into two 8ga runs. The other 8 gauge run goes to a micro sub amp mounted in a locking Smittybilt glovebox. I run a SSA Audio 12" Demon for a sub.

One thing to note: Don't expect to be wowed by the midbass, especially if you are running co-ax speakers. The ones in the dash are, for all intents and purposes, ran free-air. Basically what you would get if you took a set of speakers and set them on a work bench and powered them up. Mounting the mids from the component set in the roll bar pod improved this a little bit. While you do have somewhat of an enclosure for them, there is little airspace and that affects mid-bass response. I had a 94 Toyota Pickup that I dynamated the whole door and the 6.5" mid from my Alpine Type-R sounded freakin amazing. That's because of how much airspace the speakers got. It's just not the same in the Jeep pods.

I have some pics I can post if you're interested.

Thanks for this. OK, I like your point about getting a component set. If I understand correctly, this would allow me to commit only two channels of the amp to power four speakers: the two dash speakers and the two tweeters. Yes?

In that case, I may consider replacing my Polk 5.25 inch coaxial speakers (currently in the dash) with a set of component speakers. Then I could get away with a four channel amp, powering all six speakers. Correct?

I do already have the Polk 6.5 inch coaxial speakers in the sound bar.

 

[SouthernLJ]

Hey, thanks for all of this. Really helpful.

I’m sticking with the stock head unit out of preference. My only problems with the stock head unit are the low power and lack of Bluetooth. A Bluetooth amp seems like a simple way to fix that. Or, sure, I like your idea of simply adding Bluetooth input any other amp.

Can you tell me more about why it would be difficult to install tweeters the right way? That’s what’s behind my question about whether I would need a six channel amp, or whether tweeters can be wired with a four channel amp. I do already have the Polk speakers in the sound bar and the dash. It’s only the tweeters that I haven’t done yet.

You're going to have to have a high pass filter to protect those tweeters. Lower frequencies will destroy them. Another positive with component sets is that many have attenuation settings on the crossover so that you can dial the highs down some. Bright tweeters can be super harsh and cause listening fatigue. I have my Polk's turned down as much as I can.

 

[SouthernLJ]

Thanks for this. OK, I like your point about getting a component set. If I understand correctly, this would allow me to commit only two channels of the amp to power four speakers: the two dash speakers and the two tweeters. Yes?

In that case, I may consider replacing my Polk 5.25 inch coaxial speakers (currently in the dash) with a set of component speakers. Then I could get away with a four channel amp, powering all six speakers. Correct?

I do already have the Polk 6.5 inch coaxial speakers in the sound bar.

Give a few to round up some pics of my setup, it may be easier to show than type.

 

[SSTJ]

You're going to have to have a high pass filter to protect those tweeters. Lower frequencies will destroy them. Another positive with component sets is that many have attenuation settings on the crossover so that you can dial the highs down some. Bright tweeters can be super harsh and cause listening fatigue. I have my Polk's turned down as much as I can.

View attachment 306887

Wow, I like how you set those flush. I have heard that higher frequencies are very directional. But you get good sound out of these without having them pointed directly at you?

 

[SouthernLJ]

So I have this lil guy powering my component set. It's 4 channels bridged down to 2 so that I am at 200 watts x2 @ 4 ohms. This feeds directly to the crossovers for the component set.

The Polk crossovers are pictured here. There are getting power directly from the amp. The two gold terminals are for 4ga power and ground. The 4 Ga goes directly to the batter with a fuse near the battery. The 4ga ground goes the chassis. Where they Y off, you get two sets of 8ga power and ground for the amps. I have 2 super short runs of 8ga going to the amp that is shown. The other 2 8ga wires go to my sub amp in the glove box.

I have all of that mounted under the steering column. Note that you could lose some steering wheel up/down adjustments, but mine ended up right where I keep my steering wheel anyways. On the crossover closest to the amp, you can see that I've already ran wiring to the mid and tweeter to it. Power comes from the amp, to the crossover, and then the crossover splits the power to the mid and tweeter. While it's splitting power, it's also splitting frequencies. This is so that your tweeter doesn't get low frequencies, and your mid doesn't get super high frequencies. As I mentioned earlier, I have the tweeter attentuated as low as they'll go. On the highest settings, the tweeters will make your ears bleed.

I set the amp gain with a multimeter. You can do this by ear but I read how to do it with a DMM and gave it a try. Usually, you want to turn your stereo up to about 3/4 volume, adjust the gain up until it starts to distort, then back it down just a lil bit.

Here's some of the crap I got for the project.

Here's my pods.

I ran 12ga, if I rememer correctly, to the mids. I drilled a hole, ran the wiring through, terminated the ends, and then sealed the hole that the wiring runs through. That wiring runs back to the crossover under the dash.

These pods weren't made for 6.5" speakers, but I made it work. I had a originally got some spacers, but I didn't like it.

Instead of using the spacers, I coaxed the speaker in. It was a tight fit. On the face of the pod, I ran speaker gasketing tape all the way around it. This sealed the speaker to pod once I screwed the speaker down.

I mounted the tweets with supplied cups. I used a right angle attachment on a drill with an appropriate sized hole saw. Otherwise it would have been very difficult to the windshield angling back.

Conclusion:
My aftermarket head unit doesn't power anything. It provides signal to the mids amp which powers the mids and tweets using 2 channels of the amp. There are no other speakers other than the sub. No in-dash coax's. Just the component set and a 12". I really enjoy it. Get's plenty loud and sounds very clear. If I had it all to do over again, I'd do it the same exact way.

 

[SouthernLJ]

Wow, I like how you set those flush. I have heard that higher frequencies are very directional. But you get good sound out of these without having them pointed directly at you?

That is correct. Higher frequencies are the easiest to pinpoint where they are coming from, the opposite of lows which is why you can put a sub for a home theater system just about anywhere and it sounds still sounds good.

The mounting cups that cam with the set allow for a little bit of adjustment. You can see in the pic that they are angled a little bit towards the driver. I think that's the max amount of play, so you can angle it that much in any direction you see fit. I messed around with the aim until it sounded good to my ears. I'm not sure if where they are at currently is where they ended up sounding the best.

 

[SouthernLJ]

Thanks for this. OK, I like your point about getting a component set. If I understand correctly, this would allow me to commit only two channels of the amp to power four speakers: the two dash speakers and the two tweeters. Yes?

In that case, I may consider replacing my Polk 5.25 inch coaxial speakers (currently in the dash) with a set of component speakers. Then I could get away with a four channel amp, powering all six speakers. Correct?

I do already have the Polk 6.5 inch coaxial speakers in the sound bar.

The problem with the dash location is that there is no enclosure. It's basically free air. I don't think you'd see any improved performance with a dedicated mid in that location as opposed to a coax. Midbass will be severely lacking. The only enclosure you're going to find is the roll bar pods, and even then, meh, but it's the best you are going to get.

If it were me, and I wanted to keep a set of co-ax speakers, I would put them in the dash, and reserve the pods for the component set. But, IMO, it will sound better and easier to set up with just a component set. If you did want to run a component set and co-axs, yes, a 4 channel amp would work. 2 channels pushing the co-ax's and 2 channels powering the crossovers which run the 2 tweets and 2 mids. One thing to keep in mind is power. Component sets can take a lot of power. Unless you had a really big 4 channel, it might be underpowering the component set.

 

[skrelnik]

Learned a lot from this thread. Starting this one to be more specific to my setup:

• I have a factory head unit and I want to stick with it. Not interested in aftermarket head units.
• I have 6.5 inch coaxial Polks in the sound bar.
• I have 5.25 inch coaxial Polks in the dash.
• I have a self-powered sub (PS-8) under driver’s seat.
• I hope to add tweeters to A-pillars.

If I plan on adding tweeters, does that mean I need a six channel amp? Or can those be wired to the same channel as my dash 5.25 speakers without much loss of quality?

I would like the amp to have Bluetooth capability, and some kind of remote controls (wired is fine). I would also like it to fit under the steering column.

Any recommendations appreciated!

A few questions here, and I will answer them as GENERALLY as possible to make it easier to follow:

Speakers come in two forms, coaxial and component.
Your current Polks are coaxial so they have a tiny built-in crossover.
Components can be used in one of two ways:
An included passive crossover is generally included when you buy these speakers - Usually a 5.25: and 1" tweeter or a 6.5" and 1" tweeter plus the passive crossover are included in a set
You can toss that passive crossover and wire each speaker directly to the amplifier, so you would need a 6-channel amp in your example. You would also need to set the high and low pass filters else you would blow the speakers.

Bluetooth amps are bountiful, if keeping the same set-up, then you only need a four channel amplifier. If you add tweeters to the A-pillars, which I do recommend, Kicker makes a set of 5.25" with 1" tweeters that come with a passive crossover, and I would recommend that with the 4-channel amplifier.

Amplifier

https://www.crutchfield.com/S-r6VxpaG0O2K/p_530ST410DB/Soundstream-ST4-1000DB.html
5.25" + tweeters and mounting hardware:

https://www.crutchfield.com/p_20647KSS50/Kicker-47KSS504.html

 

[SSTJ]

The problem with the dash location is that there is no enclosure. It's basically free air. I don't think you'd see any improved performance with a dedicated mid in that location as opposed to a coax. Midbass will be severely lacking. The only enclosure you're going to find is the roll bar pods, and even then, meh, but it's the best you are going to get.

If it were me, and I wanted to keep a set of co-ax speakers, I would put them in the dash, and reserve the pods for the component set. But, IMO, it will sound better and easier to set up with just a component set. If you did want to run a component set and co-axs, yes, a 4 channel amp would work. 2 channels pushing the co-ax's and 2 channels powering the crossovers which run the 2 tweets and 2 mids. One thing to keep in mind is power. Component sets can take a lot of power. Unless you had a really big 4 channel, it might be underpowering the component set.

OK, thanks again. These posts are really helpful.

My overhead sound bar already has Noico butyl product and poly fill. In the front, I have 3-D printed pods with Noico and poly fill also. So, I know it’s still not a great set up, but it’s better than free air. I guess I would just need to decide which set of coaxials to replace with a component set, either the front dash ones or the overhead ones.

Naïvely, when I first heard your suggestion of a component set, I didn’t realize that would also call for crossovers. Makes sense, but this is starting to sound like it might be more expensive than I planned.

I realize how cheap this sounds, but I’m just curious, for the sake of understanding: what if I just installed two tweeters, wired them to the same channels as the 5.25s, and installed an inline frequency blocker doohickey, to protect the tweeters from any lower frequencies?

Again, I think this idea has problems, I’m just eager to understand what they are for the sake of learning.

 

[112dB]

The problem with the dash location is that there is no enclosure. It's basically free air. I don't think you'd see any improved performance with a dedicated mid in that location as opposed to a coax. Midbass will be severely lacking. The only enclosure you're going to find is the roll bar pods, and even then, meh, but it's the best you are going to get.

The dash pods I have do give you an enclosure, but its way too small. Most speakers are designed to go into doors, which are large cavities, bordering on being a free-air config. The .25 cu ft or whatever the pods provide is way too small, but I thought better than having the drivers in the dash, free air. (You want to separate the sound waves coming off the front of the speaker from the back waves, which is why home speakers are built into cabinets.) I have found some 3D printer plans for slightly larger pods and plan to give them a try, eventually.

 

[SSTJ]

A few questions here, and I will answer them as GENERALLY as possible to make it easier to follow:

Hey, thanks very much. Love this forum.

Speakers come in two forms, coaxial and component.
Your current Polks are coaxial so they have a tiny built-in crossover.
Components can be used in one of two ways:
An included passive crossover is generally included when you buy these speakers - Usually a 5.25: and 1" tweeter or a 6.5" and 1" tweeter plus the passive crossover are included in a set
You can toss that passive crossover and wire each speaker directly to the amplifier, so you would need a 6-channel amp in your example. You would also need to set the high and low pass filters else you would blow the speakers.

Ok great, that makes sense. I assume that 4-channel amps are smaller and cheaper. Could I also use a 4-channel amp with the passive crossover that usually comes with a set of component speakers?

Bluetooth amps are bountiful, if keeping the same set-up, then you only need a four channel amplifier. If you add tweeters to the A-pillars, which I do recommend, Kicker makes a set of 5.25" with 1" tweeters that come with a passive crossover, and I would recommend that with the 4-channel amplifier.

Ha, yes, there it is. Got it.

If you add tweeters to the A-pillars, which I do recommend

I actually like the flush-mount approach that @SouthernLJ took, so I might still take that approach. I also enjoy dropping the windshield sometimes, so I'm beginning to think that the A-pill approach isn't for me. But I could still use what you've recommended and mount them in the location that @SouthernLJ took.

Follow-up Questions, if I may:

• May I ask about @SouthernLJ's concern that a 4-channel amp might not have enough power if two of its channels were being used to power the four speakers of a component set?
• I've seen that amp you recommended, on Crutchfield I think, but I also like the Kenwood that Crutchfield sells, for its wired remote controls. Any particular reason you recommend that amp over others like the Kenwood?

 

[skrelnik]

Have you already purchased the gear listed, or are you in the planning stage? Whats the purpose of the stock head unit? are you planning to use it or is it just there to deter theft?

if you want to fade between the front/rear you'll need a 4 channel amp. (If you don't, you can wire your front and rears for each side to one channel, but there are caveats there...) Go with coaxials (tweeter mounted on the driver) in the overhead/soundbar and a pair of components ( separate 5.25 and tweeter ) for the front dash speakers.

You could wire in an additional set of tweeters, but to do it properly would be too much of a hassle and the sound would still likely be horrible.

As for the amp, you can also use something like the audiocontrol ACX-BT1 to add a bluetooth input to any amp. ( https://www.audiocontrol.com/car-audio/accessories/acx-bt1/ ) I have one. It was great. it died, but AC is sending me a replacement. If you go this route, you'll need a 12v+ turn on (usually a blue wire). the ACX-BT1 has this, but others such as the JL Audio Marine one does not.

Be aware of sensitivity ratings - speakers with 90+ db sensitivity will give you more output than those with 85-86 db. It's a noticeable difference, and the higher sensitivity means you can get away with using a less powerful amp.

https://www.crutchfield.com/p_530ST410DB/Soundstream-ST4-1000DB.html?tp=115 <- that may work for you but if I was going to do a 'headless' stereo, I'd probably use the ACX-BT-1 and then pick out a 4 channel amp to go with it. Then again, the simplicity of having the BT built in is a plus. FYI - I like crutchfield because I live in a small little town and get grumpy if I have to drive more than 7 miles and the nearest 'real' stereo shop is ~50 miles away.

I mounted my amp under my steering wheel. more details here: https://wranglertjforum.com/threads/112dbs-2002-sahara-stereo-install-saga.36035/

Beware of misinformation like the sensitivity ratings, personally I do not even look at those ratings because of how useless they are. There is a curve where sensitivity is measured, and no two manufacturers use the same methodology, so these numbers can be skewered. Sensitivity shows how loud a speaker plays, and nothing about the quality. For tweeters I would rather have quality, but subs maybe I only care about the pounding, but that is a real sub (between 10" and 15"), not a 6.75" sub in our TJ.

Also, Don at Unexpected Creations will build you stuff and send it to you. Custom boxes, wiring and high-quality gear at reasonable prices. Our fearless leader, Chris who runs this forum, purchased a lot from him. Crutchfield is great but sometimes it's time to move on, sort of like the people who start at quadratec and then move on to other brands like Currie, OME, JKS etc.

https://unexpectedcreations.com/

 

[SouthernLJ]

OK, thanks again. These posts are really helpful.

My overhead sound bar already has Noico butyl product and poly fill. In the front, I have 3-D printed pods with Noico and poly fill also. So, I know it’s still not a great set up, but it’s better than free air. I guess I would just need to decide which set of coaxials to replace with a component set, either the front dash ones or the overhead ones.

Naïvely, when I first heard your suggestion of a component set, I didn’t realize that would also call for crossovers. Makes sense, but this is starting to sound like it might be more expensive than I planned.

I realize how cheap this sounds, but I’m just curious, for the sake of understanding: what if I just installed two tweeters, wired them to the same channels as the 5.25s, and installed an inline frequency blocker doohickey, to protect the tweeters from any lower frequencies?

Again, I think this idea has problems, I’m just eager to understand what they are for the sake of learning.

I've never seen a component set that didn't include the X-overs. As far as using inline frequency blockers, I've never tried it, or listened to a setup like that, so I have no input. The first thing that comes to mind is being able to adjust the tweeters. If you've never heard tweeters that were to high/bright/harsh, it's painful to the ear and ruins the listening experience. Before I adjusted mine, my ears would start hurting after a couple songs when I had the volume up decently high. Cranking it up to the max was unbearable.

I wish I had more input on your proposed setup with the 5.25" together with the tweeters.