OK, Audioheads - Time to exercise your brain (12 speaker upgrade Mids/Tweet)

:hail: - First off, greetings Audiophiles, and tell me what YOU think...

So, 2015 EBP PP 201A (12 Speaker)
2 Ohm 8" Subwoofer (DVC)
2 Ohm (2 way) 6.5" Rears
4 Ohm 6.5" Midbass
8 Ohm 3.5" Mid
2 Ohm 3.5" Center
8 Ohm 1" Tweeter

Why?
1. It's cheap.
2. It's safe.

You see, the Mid and Tweeter are on the same circuit in parallel with no crossover, only a 4.7uF "bass blocking" capacitor on the tweeter input lead (+), at 8 Ohms this is about 4K.
A GROSS over simplification would be:
1/Rt [Ohms Total] = 1/R1 + 1/R2 [Ohms of each speaker on the parallel circuit]

Where 1/Rt = 1/8 + 1/8 or
1/Rt = 2/8
1/Rt = 1/4
Rt = 4 ohms for the 3.5" Mids and 1" Tweeter circuit around the crossover frequency (+/-)

So, it would appear that the 6.5" Midbass + 3.5" Mid/Tweeter circuit and the rear speakers are ALL powered by amplifier channels capable of 4 Ohms OR LESS (because why would the center and Subwoofer channels be 2 Ohms and not the others? But I digress).

...but wait, there's more!

The "bass blocking" capacitor creates increased impedance below a certain frequency based on the impedance of the circuit creating some WILD impedance measurements overall. So the 4.7uF Capacitor at 8 Ohms is (roughly) a 4,233Hz crossover, the impedance at 2,000Hz could be 8 Ohms (Mid) and 32 Ohms (Tweet)

Where 1/Rt = 1/8 + 1/32 or
1/Rt = 4/32 + 1/32
1/Rt = 5/32
Rt = 6.4 Ohms total AT THAT frequency (No wonder active crossovers are preferred!) :eyebulge:

This would create a dip in the Mids due to increased impedance, but the highs are cut 6db per octave (1st Order High Pass Filter) until the filter point is reach and going to -3db (since BOTH speakers are active) so there will be no perceptible volume change. Above this "blocking" point, there is a NO db loss since BOTH speakers are active above the "bass blocker" frequency, we go back to 4 Ohms total (see above).
Yes, eventually the sound goes well above the efficiency/capability of the 3.5" Mid and it's output slowly diminishes, that's when the tweeter shines... (well, not ours because they fall flat on their face above 10,000Hz)

Sheeew...

So, what can we do?
How about a 4 Ohm 3.5" Midbass through a Low Pass Filter (or Band Pass - easier to find) coupled with a 4 Ohm 1" Tweeter that goes through a FULL High Pass Filter (Capacitor and Inductor)?

I'm testing the factory speakers with crossovers and 8 Ohm speakers with crossovers - then (eventually) 4 Ohm speakers and crossovers if I don't like what I hear with the 8 Ohm set up. I'm guessing the 8 Ohm issue is to keep the mids and highs from totally washing out the Subwoofer (kind of like the Midbass issue we already have).

Because why give up almost 50% (or more) of our rated power if we don't have to?

[Ref]

I'm curious about this

OK, first results with the Dayton AMT (Air Motion Transformer tweeter) in 8 Ohm, these dropped right in the factory mount perfectly and with a piece of double stick tape on the outer case or a dot of hot glue would be a seamless install. The sound was a nice, but just didn't do it for me. I did get some 12,500Hz test tones that I didn't see or hear with the stock (peaked at 10KHz, 12.5KHz was inaudible and could not be see above background noise on the Android RTA Pro app).

What I did notice was a very "Crisp" and "Airy" sound that I really liked, but only if there was more of it. Imagine absolutely LOVING one of two notes in an entire song, or a second or two of a guitar/keyboard solo. The "Off-axis" listening was less than stellar, to get the full effect meant sticking your head under the rearview mirror - not very practical for daily driving. A real shame. If these were available in a 4 Ohm version or if I had room for a second set in parallel (dropping the tweeter circuit to 4 Ohms), these would be awesome. So, I can't see myself pursuing any more 8 Ohm options.

On to the 4 Ohms!

First up Polk db1001 1" tweeters - 4K to 23KHz response starts with a 4KHz crossover/bass blocker/tweeter protection/-3db option circuit that isn't TOO bulky, but may prove challenging to hide. The tweeter itself, although listed as 1", does NOT fit in the factory 1" hole - without some trimming/mods. Initially installed with a Dayton AMT on the passenger side and the Polk on the driver side, the Polk is NOT as crisp, it was definitely bright, more apparent and easily reproduced the 12,500Hz tone just like the AMTs did.
Just need to temporarily get them in the pillar without too much effort so I can continue some side-by-side listening.

Cutting the heat-shrinked Crossover/Bass Blocker/Protection module reveals quite a bit - there is an actual circuit board with 5 components for a pretty sweet Second Order (-12db) High Pass Circuit:
"PS" - Ceramic disc capacitor (single layer) circuit protection cap
C1 and C2 Combine in parallel for a 8uF Capacitance to block everything below 2,485Hz (@ -6db Linkwitz-Riley?)
R1 is a 5w Resistor, presumably to give us the -3db "yellow wire" to snip if the tweeters are too bright.
L1 is a TOTAL mystery - no visible markings, but it is most likely a .512mH Inductance Coil to help form the "4K High Pass crossover"

[On deck - AMT 4 Ohm, Pioneer Hard Domes]

OK, spoke too soon - I never installed the AMT 8 Ohm in the drivers side and I didn't test them with the 4K crossover, so we're going to back up a bit. Just got a little excited when the Amazon driver pulled in the driveway I guess...

AMT 8 Ohm in both sides with no crossover (not recommended), looking for defects like "Silibance" (6K-8K) or "Brittleness" (8K-16K). It sounds MUCH better than one stock and one AMT or one Polk and one AMT.

The "Star" performance was Shinedown - "How Did You Love (Acoustic)" (or any song featuring a bronze stringed acoustic guitar) - the realism and presence were incredible. You could hear the pick strumming strike on each string.

I'm a bit lost, which tweeter did you ultimately like in the last post? This 4ohm AMT? https://www.parts-express.com/dayto...-transformer-automotive-tweeter-pair--275-195

When all your analysis is done, please tell me which center speaker you liked. I have the 12 speaker set-up.

Captdistraction said:

I'm a bit lost, which tweeter did you ultimately like in the last post? This 4ohm AMT? https://www.parts-express.com/dayto...-transformer-automotive-tweeter-pair--275-195

Click to expand...

I went back and installed BOTH AMT-8's (8 Ohm), but still testing...

https://www.parts-express.com/dayton-audio-amt-mini-8-air-motion-transformer-tweeter-8-ohm--275-095

Edit: I liked them both, but if forced to choose, it would be the Polks out of these two. They are smoother, sound great and are always "there"; whereas the AMTs sound good, and absolutely SHINE about 5% of the time.

yep I'm sure confused

So far we have:
Stock 8 Ohm - Meh
AMT 8 Ohm, no crossover
AMT 8 Ohm, Polk 4K crossover
Polk 4 Ohm, Polk 4K crossover

It's way too early to pick one, since 2 more sets arrive this week. Besides, they're tweeters, arguably the most personal of all speakers. So many choices...

Adding a chart tomorrow, sadly it will probably make things worse...

It is the Focal Test CD plotted by weighted peak db for each frequency.
See this.

EcoBOSS said:

OK, first results with the Dayton AMT (Air Motion Transformer tweeter) in 8 Ohm, these dropped right in the factory mount perfectly and with a piece of double stick tape on the outer case or a dot of hot glue would be a seamless install. The sound was a nice, but just didn't do it for me. I did get some 12,500Hz test tones that I didn't see or hear with the stock (peaked at 10KHz, 12.5KHz was inaudible and could not be see above background noise on the Android RTA Pro app).

What I did notice was a very "Crisp" and "Airy" sound that I really liked, but only if there was more of it. Imagine absolutely LOVING one of two notes in an entire song, or a second or two of a guitar/keyboard solo. The "Off-axis" listening was less than stellar, to get the full effect meant sticking your head under the rearview mirror - not very practical for daily driving. A real shame. If these were available in a 4 Ohm version or if I had room for a second set in parallel (dropping the tweeter circuit to 4 Ohms), these would be awesome. So, I can't see myself pursuing any more 8 Ohm options.

Click to expand...

Sounds like you proved a couple of things... the nature of the Daytons and other drivers that use this technology is that they are definitely an on-axis driver. So if you listened to them in your living room about 10' away, they would sound awesome all the time! The second thing is that a car is a less than optimal environment for true stereo reproduction... which sucks, because that's why we're all here, right? :(

They use different ohm-ratings to manage heat and power requirements in a very small amplifier given the bare minimum gauge of wire ultimately from the battery. You can get away with lower ohm on the 3.5 and tweeter - probably - but don't play that game with the midbass or subwoofer.

here is a kind of general question, given the only thing we are talking about replacing is the speakers. Also we are locked down into two channel output for the doors do we know the factory crossover point? On the 9 speaker system rear deck are woofers again what is that crossover point. On 12 speaker system the rear deck gets two way speakers so mid bass to midrange crossover?

So its looks like Ford can change head amp settings, has anybody compared a 9 to 12 as built to see what Ford might be doing.

It would be nice to put in better speakers get higher efficiency and better tonal, then tweak the head end Xovers and levels. turn off noise enhance system.

Yeah, about that...
And the fact that Ford pointed the tweeters at each other...

Settings: Left side front only, Bass/Mids/Treble to "0"
Tools: Focal Test CD, Radio Shack 33-2055 Digital Sound Level Meter. MS Excel

See the color coded labels at the bottom of the graph:
Gold - Background - this is our db floor (39db actually) - listed as 40db for simplification
Light Blue - Stock, no crossover, subwoofer stuffed with Poly-Fil
Gray - Stock with 4K Polk crossover on factory tweeter
Gold - Dayton AMT-8 tweeters (direct)
Dark Blue - Dayton AMT-8 tweeters with 4K Polk crossover
Green - Polk db1001 with Polk crossover

First, compare Light Blue and Gray - this is JUST with the addition of the crossover (-12db 2nd Order) that shows that even the stock tweeters can benefit from a quality crossover - but don't bother, they fall flat on their face at 10K. Notice how the "curve" is affected all the way down to 500Hz - this is due to the crazy impedance issues with multiple speakers discussed earlier.

Next is Gold and Dark Blue shows the benefit of a crossover on the AMT-8 and the extended highs (12,500Hz). This tweeter would be GREAT for a "no fuss" drop-in for someone keeping the 8 Ohm set up if you listen to acoustic, classical and such. That 5-6K peak makes for some incredible "presence" in acoustic guitar and other strings. Off-axis volume is tricky, but it is livable. Total "stealth" install.

Finally the Green - Polk w/ the Polk 4K Crossover, install is going to be MORE involved (remove factory grille and some grinding), the cover has logos and is gray and black - not a "stealth" install at all. Extended 6.3K to 10K output has better definition all around - great of any music, but you MAY have to snip the -3db yellow wire on the crossover. I had to reduce my Treble from +3 to -3!

What does this mean? You need tweeters, they suck.
Find something nice in 4 Ohm and make sure it has more than a -3db 4.7uF cap for a "crossover".

Polk db351's and Crossover parts arrive this week - going to see what a "High Pass" crossover does for these result...

Most auto manufacturers point the tweeters at each other even if it is bad practice because it looks good.

Outstanding source for terms and stuff...