Replacing front/rear woofers on EX with a two-way speaker: would the tweeters on the two-way work?

[SSMEX]

I have a 2017 EX sedan and would like to upgrade the speakers only. The Polk Audio DB 652 (two-way) seems to be a popular and fairly cost effective option, but I'm totally confused as to how a two-way speaker works when replacing the stock woofer.

My understanding is that the EX has eight channels—

• Four woofer channels (two in each front door, two behind the back seat headrest)
• Four tweeter channels (same locations)

—and that there's a factory crossover that happens inside the amplifier that separates low/mids from the highs such that the former goes into the woofers and the latter into the tweeters.

Does this mean that the tweeters in the DB 652 are entirely unused? If so, can the tweeter channels be piped back into the woofer? Of course, not having to replace the tweeters would make the project significantly easier.

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[bikejog]

—and that there's a factory crossover that happens inside the amplifier that separates low/mids from the highs such that the former goes into the woofers and the latter into the tweeters.

Yes there're 'crossovers', but not at the output of the amplifiers, but at the input. Each tweeter and midrange is driven by a dedicated amplifier. The midrange amplifiers output frequencies up to around 5KHz and the tweeter amplifiers output start around the same frequency.

Does this mean that the tweeters in the DB 652 are entirely unused?

Depends on the crossover point of the Polk. If the crossover point is < 5kHz, then it will be used from the crossover point to 5kHz.

If so, can the tweeter channels be piped back into the woofer?

You mean to route factory tweeter back to the Polk? There're two ways.

1. Use a DSP to combine the factory tweeter and midrange outputs and feed that combined output to an external amplifier that drives the Polk.
2. Not recommending you do this, but it can be done. Looks like with a little diy, you can bi-amp the Polk. Unsolder the Polk's crossover and connect factory midrange output to the woofer and the factory tweeter output to the tweeter. If the Polk midrange and/or tweeter is not a good match to the factory crossover points, then some frequencies will not be produced. But this has the same problem if you were to drop in a set of aftermarket components.

 

[SSMEX]

Wow this is awesome.

1. Not recommending you do this, but it can be done. Looks like with a little diy, you can bi-amp the Polk. Unsolder the Polk's crossover and connect factory midrange output to the woofer and the factory tweeter output to the tweeter. If the Polk midrange and/or tweeter is not a good match to the factory crossover points, then some frequencies will not be produced. But this has the same problem if you were to drop in a set of aftermarket components.

This is really interesting, and may be worth a try. Is it necessary to remove the crossovers if the factory tweeter positive is soldered to the circuit post-crossover? If that's problematic, I might just connect to the tweeter wires directly. I suppose it could be problematic that the Polk crossover point is lower than the factory amplifier crossover point and that the frequencies between these points disappear entirely?

 

[bikejog]

Is it necessary to remove the crossovers if the factory tweeter positive is soldered to the circuit post-crossover?

I'm not sure what you mean by post-crossover?

 

[SSMEX]

I'm not sure what you mean by post-crossover?

As in soldering the factory tweeter output to the part of the circuit that is after the crossover components.

 

[bikejog]

As in soldering the factory tweeter output to the part of the circuit that is after the crossover components.

Below is a simple passive crossover circuit. It's not your Polk's crossover. So you're saying connect the midrange and tweeter amp outputs as showed in the first pic? The answer to that is no (don't do it) because the midrange and tweeter amplifiers will be connected together via the 39uF cap. That's a no-no.

The Tweeter+ and Woofer+ labels in my previous diagram might not be correct after some more thinking. I'll remove those labels. But you can clearly trace where the woofer (copper) and the tweeter (black) wires go.

A simple way is just disconnect the Polk tweeter wires from the Polk crossover and connected them only directly to the factory tweeter output. But it is not ideal since the Polk Crossover is still connected to the midrange and it can roll off the midrange earlier than the factory signal provides resulting in a dip in the midrange and it also introduces some phase shift.

So the best solution is to disconnect the Polk Crossover. And if you know what you're doing, you don't have to unsolder everything like as an example showed in the second pic. You just have to unsolder enough so the tweeters and woofers are isolated. After thinking this over, having a common GND for two different amp channels might not be a good idea for car amps. So I've removed mention of common GND.

If you can detail how the Polk speakers and crossovers are wired, then we might be able to help you further. In lieu of that, you can just remove all the crossover components and check to make sure the tweeter and woofer wires are isolated with a DMM before connect them to the amps.

EDIT: Removed common GND.

 

[SSMEX]

This is incredible information. I'm going to give this a try and report back. Despite the extra work involved, I think this is much easier, cleaner, and cheaper than having to replace the factory tweeters, especially if you're concerned about reversing this mod before any sale. Thanks so much for these diagrams and descriptions!

The answer to that is no (don't do it) because the midrange and tweeter amplifiers will be connected together via the 39uF cap. That's a no-no.

Good to know. Without any warning, I probably would've tried this first.

A simple way is just disconnect the Polk tweeter wires from the Polk crossover and connected them only directly to the factory tweeter output. But it is not ideal since the Polk Crossover is still connected to the midrange and it can roll off the midrange earlier than the factory signal provides resulting in a dip in the midrange and it also introduces some phase shift.

I figured the Polk crossover on the woofer only was potentially an issue. I might do a quick test to determine where the crossover point is, just for completeness's sake.

 

[bikejog]

This is incredible information. I'm going to give this a try and report back. Despite the extra work involved, I think this is much easier, cleaner, and cheaper than having to replace the factory tweeters, especially if you're concerned about reversing this mod before any sale. Thanks so much for these diagrams and descriptions!

The only pro of doing that is cheap. There're tweeters out there you can do none destructive installs. My Focal k2 power 165kr for instance. I can revert back to stock when I sell my car. If you route the factory highs to the Polk, then the tweeter will be way below ear level. It's ok I suppose, after all, that's the way it was before the mid-90s.

I think the first thing you should try is to simply connect the factory midrange output to the Polk as is. The Polk will produce all the frequencies from the factory midrange output. The only potential downfall is if the timbre is way off, then it may sound awful. And there's gonna be some frequency shift, but my understanding is that's more of a concern when integrating the midrange and the sub.

 

[86salmon]

Are you replacing all four door speakers? Wouldn't it be simpler to just use component sets or raw drivers?

 

[SSMEX]

Are you replacing all four door speakers? Wouldn't it be simpler to just use component sets or raw drivers?

I have the sedan so the two rear woofers and tweeters are on the rear shelf, but yes I'm replacing at all four corners. My main motivation for using a two-way speaker is to avoid dealing with tweeter mounting. I know there are non-destructive tweeters, but they cost more and require removal if I want to sell the vehicle. The only downside to modifying the two-way speakers is the extra initial complexity and the fact that the tweeters are lower than they ideally should be.

 

[86salmon]

I have the sedan so the two rear woofers and tweeters are on the rear shelf, but yes I'm replacing at all four corners. My main motivation for using a two-way speaker is to avoid dealing with tweeter mounting. I know there are non-destructive tweeters, but they cost more and require removal if I want to sell the vehicle. The only downside to modifying the two-way speakers is the extra initial complexity and the fact that the tweeters are lower than they ideally should be.

I would spend more for a better component set for the front and not even bother with the rears. The rear deck is a pain to take apart (I've done it twice... Ugh) and they're mostly for fill anyways

Another option is deadening the doors and just replacing the tweeters. It's amazing how big a difference even that made for me before I added my subwoofer

I have these right now
https://www.parts-express.com/Peerless-OT19NC00-04-3-4-Fabric-Dome-Tweeter-4-Ohm-264-1122

They sound worlds better

 

[bikejog]

I would spend more for a better component set for the front and not even bother with the rears. The rear deck is a pain to take apart (I've done it twice... Ugh) and they're mostly for fill anyways

I have to agree with that. A set of component of the same model is usually no more than 50 more.

And one thing I just thought about now is you really don't know the actual impedance of raw woofer and tweeter Polk drivers. It's possible they used a 4 ohm woofer with an 8 ohm tweeter and what not. So maybe you should do more research before going to bi-amp the Polk.

 

[Ksthomas]

My understanding is that both the tweeters and woofer are receiving a full range signal and the “crossover” is the small capacitor on the factory tweeter (I have a hatchback, for the record). I recently installed Infinity 6530cx components, an LC2i and a JBL amp and I used ONLY the factory tweeter wires into the crossover. The factory wires that were connected to the woofer are completely disconnected and I’m getting a full range signal to the Infinity crossover. The harness on the back of the head unit only has 8 wires (4+ and 4-). Those wires appear to just split without a crossover at some point before the door.

 

[bikejog]

Oops @Ksthomas is correct. @SSMEX, you don't need to mod the Polk speakers at all. Just do what Ksthomas did. I was confused your EX with an EX-T. What I said apply to the EX-T. Not the EX. Sorry!

Don't do what I said. If you connect the factory tweeter output to the raw Polk tweeter and crank it up, then you'll likely blow the Polk tweeter.

 

[Gi.Pax]

Sorry to come in forth but i need to know. With premium 12speaker sound system i will found dedicated outputs for door speaker? no need for crossovers that comes in with the upgrade speaker kits?

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