# Slope / Tweeter Decisions on Focal Set-up



## Analog Values (Jan 19, 2017)

As a newcomer to your community _(first posted this weekend in new member introductory forum)_, I’d very much appreciate your advice regarding installation of new car speakers. Here is my situation:

*Vehicle:* 2017 GMC Sierra 1500 Crew Cab, SLE Premium Plus Package, Premium Bose system with subwoofer in center console.

*Plan:* Replace Bose factory system _(other than head unit)_ in a three phase approach.

•	*Phase 1:* Replace factory speakers with Focal ES 165KX2 component and Focal EC 165K coaxial speakers. Purchase made (good deal on them), with installation scheduled for February 9th – 10th. These will be powered by Kenwood Excelon 400XR-4 stop-gap Phase 1 amplifier. Bose subwoofer will continue to be powered by factory amplification _(I guess, unless it proves to be more of a liability than asset)_.

•	*Phase 2:* Install pre-amp (DSP) along with quality amplification, replacing Kenwood Excelon 400XR-4. May use bridged Kenwood to power Bose subwoofer _(in the event that does more good than harm)._

•	*Phase 3:* Add subwoofer and sub-amp.

*My question is this:* The slope, tweeter level and tweeter shelf installation decisions outlined below will be made by my installer, as I have no guidance to provide. I’ll simply rely on his ear and his experience to make those calls. Yes, I know what you’re thinking: “if you were installing these speakers yourself, you could make those decisions with your own ear, *******”. However, that said, are there any rules of thumb guiding these decisions?

•	*Slope:* The high-pass crossover slope is 12 dB/octave. A switch on each crossover allows me to choose between 18 dB/octave and 12 dB/octave slopes for the high-pass crossover. Another switch allows me to choose between 12 dB/octave and 6 dB/octave slopes for the low-pass crossover. The crossover point for both is 3,000 Hz.

•	*Tweeter Level:* A three position switch on the crossover allows me to adjust the output level of the tweeter to -3 dB, 0 dB, or +3 dB.

•	*Tweeter Shelf:* Another switch on the crossover turns on/off a high-frequency boost, designed to improve definition.

*Focal Speakers:* Just prior to this post, I did take an opportunity to look up some previous threads on Focal speakers. There seems to be quite a diversity of opinion, and I suspect the answer to my question above will simply come down to individual taste _(as most things do). _I’ve actually never listened to the speakers I bought, nor any competitors in the same price range. For Phase 2 amplification, I suspect I’ll drive to some not-so-nearby city to listen to equipment which caught my fancy, absent the opportunity to actually compare it to anything else. Ironically, the number one principle for judging audio equipment is listening to music in a side-by-side comparison. Ironic, because that’s virtually impossible to do. Instead, I read about equipment hoping to find brands complementing my philosophical bent, and end up purchasing equipment I’ve never heard. It’s a barbaric world, wherein my hope for survival is gut instinct and a little help from friends _(such as yourselves)_.

The primary con I’ve read about Focal is that is has an edgy tweeter _(a legitimate concern given the bright nature of digital format to begin with). _I may very well suffer tweeter fatigue in Phase 1, but perhaps address it with a Phase 2 DSP. The reason I bought Focal is it seems to be a top brand in my area, and I got a good deal on these particular speakers. I was looking at the flax, but lucked into a highly discounted upgrade. You’ll laugh at this, but my original plan was to start at the front-end, and work my way backwards to the speakers. However, I was convinced by my dealer that any amplification I was looking at would fry my factory speakers, so I needed to start at the back-end instead. Oh well. I don’t know what they’ll sound like, but I got a good deal on speakers that should be of decent quality. Time will tell. One can only do what one can do.

Thank you for your help!


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## Alrojoca (Oct 5, 2012)

Not sure I quite got all you wrote, but if you decide not to use the focal passive crossover and decide to use a DSP with pandpass active crossover, I would start with -24db slopes.

Keep in mind you need 4 channels for active or DSP offering the bandpassing active network for a 2 way front. 

Not easy since you need to match level woofers and tweeters to hear a balanced and smooth response. You will also need to High pass and Low pass each tweeter and woofer and a frequency gap may be hard to prevent unless the woofer will play high enough to the lowest frequency the tweeter can handle, oh wait, 3Khz, then I would set the DSP like this:

-24 db slopes for both, tweeter HP at 3000 hz, either no low pass or LP at 20khz, woofers LP at 2500 Hz to start, (maybe others know those Focal woofers better) most 6.5" should be crossed betwee 1800 and 2400 Hz, this will be the gap but you can boost EQ between say 2000 and 3000 hz, it is just aboutr trying and tuning, 12 db slopes may work, using 24 db slopes the drivers will have more protection, less stress and the tweeter's sound is less harsh with steeper slopes. 

Then using the focal passive crossovers, you will need only 2 channels versus 4 (biamp), much easier since no level matching needs to be done between the woofer and tweeter, or just the flip of the crossover switches until it sounds good. 

Not sure if this helps or answers at least a fair portion of your question. DSP=hours of tuning and trying X points, slopes etc. Passive is just plug and play 15 min set up and you still will have 2 channels for rear speakers or keep the ones you have working and most likely distracting or polluting your front stage if the levels are not reduced to create ambience for a good stage.


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## Lycancatt (Apr 11, 2010)

use the 12 db slopes on both, and the -3 db position on the tweeter level. if you need the shelf, you can create it in the stock radio..or something like it. that kenwood is actually a pretty good amp and I'd suggest using it unti everything else is upgraded because that amp upgrade money can be better spent on door deadening and a proper dsp.


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## MacLeod (Aug 16, 2009)

I'd set the crossover to -3 db. In nearly 30 years of fiddling with car audio I've never heard a passive crossover that sounded better at 0 db. -3 or even -6 db have always worked better for my ears. 

I wouldn't worry about the tweeter shelf thingamajig. You can mess with that if/when you get a DSP or little better EQ. That'll be a more proper way of tweaking those things.

You should be good with those Focals. I've been a fan of Focal for a couple decades now. Morel and Scanspeak are tied for my #1 favorite but Focal are awful close. Yes they can have a bit of a bite in a car environment but after some tweaking and tuning and maybe even a little elbow grease you can get them sounding very sweet especially for music like jazz or classical and rock.


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## 08Diesel (Dec 10, 2016)

Emailed focal (have a similar setup) he said to cross them at 3500 hz with a 24 db slope


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## Alrojoca (Oct 5, 2012)

08Diesel said:


> Emailed focal (have a similar setup) he said to cross them at 3500 hz with a 24 db slope


That's sounds like a manufacturer is CTA, extreme protection behind 

What they say isn't always what we should do. One way to know is knowing the FS value, then double that and with a 12 or 24db slope would be fine.

Sometimes it is hard to know the FS value since some manufacturers do not show it or takes time to find it.

I just checked them, I was not aware they had a biamp passives, looks like a great set and high priced too. Very good power handling, glad to see Focal steeping up in power handling since their sets use to handle like half the power of what these handle, even for the expensive models.

For the ones using a DSP, and plan to remove the passives, the FS is 1500hz, for that set, this means they can be crossed at 3000hz safely with a -12db or steeper slope.


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## MacLeod (Aug 16, 2009)

The Fs may tell you how low you can safely cut a tweeter but it doesn't always mean it'll sound good that way. Once you get below 2.5K, it's been my experience that they don't sound good and really start to sound kinda nasally with too much bite. Now larger tweeters like 2" would likely be different but I just think a little 1" dome is gonna have have limits to what it can reproduce and still sound good. My old Scan tweets could easily play down to 2K but no matter what car I used them in or tweaking tricks I tried, I always wound up with them at 3.2K.


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## Analog Values (Jan 19, 2017)

Thank you very much for the technical feedback. I’ll digest all of this and have a conversation with my installer.

I also appreciate the positive feedback from Lycancatt on the Kenwood amplifier. That’s encouraging with respect to Phase 1 performance, and I may incorporate a two channel bridge configuration for rear door backfill speakers in the ultimate configuration. _(Maybe, don’t yet know.)_

I’ll post a more serious inquiry later on about Phase 2 equipment I should investigate. However, I will say, I’m surprised and befuddled by the bi-amping situation:

•	Focal recommends that these speakers be bi-amped. So far, so good.

•	However, my installer is unwilling to bi-amp the speakers, because he says the risk of blowing out a tweeter is too great. What?

•	And when I ask people about bi-amping, I generally get the sentiment expressed by Alrojoca earlier in this post. Bi-amping *could possibly *sound better, *if* someone *properly* tunes a *good quality* DSP. The underlying implication is that the average dweeb _(such as myself)_ has virtually no shot of getting it right.

What do you think? Is the risk of blowing a tweeter too great to take? Is successful bi-amping beyond the reach of average dweebs? _(You can be honest; I have a thick skin.)_

I’ll leave you with this survey question. MacLeod is aware of my struggle in transitioning from home audio to mobile sound. That said, if I reminded my installer to cut the same length of wire for each speaker wire, would he think:

A: “that goes without saying, dickhead”, or

B: “who does this prissy ******* think he is?”

Looking forward to survey results…..


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## MacLeod (Aug 16, 2009)

Analog Values said:


> •	Focal recommends that these speakers be bi-amped. So far, so good.
> 
> •	However, my installer is unwilling to bi-amp the speakers, because he says the risk of blowing out a tweeter is too great. What?


You might need a new installer.



> •	And when I ask people about bi-amping, I generally get the sentiment expressed by Alrojoca earlier in this post. Bi-amping *could possibly *sound better, *if* someone *properly* tunes a *good quality* DSP. The underlying implication is that the average dweeb _(such as myself)_ has virtually no shot of getting it right.


Bi-amping is a great way to dial in some really good SQ even thru a passive crossover. Being able to adjust the tweeter's gain in relation to the mid's can give you a lot more flexibility in dialing in the sound. Ya gotta think, those crossovers were designed while the speakers were likely mounted into bookshelf speakers and not in a car. Even if they were, with the million different cars and the million different possible mounting locations, it would be impossible for them to dial it in perfect for every application. With a dedicated amp channel, you can dial in the tweeter level independent of the mid and to a level that works best for your ears.



> I’ll leave you with this survey question. MacLeod is aware of my struggle in transitioning from home audio to mobile sound. That said, if I reminded my installer to cut the same length of wire for each speaker wire, would he think:
> 
> A: “that goes without saying, dickhead”, or
> 
> ...


Well let me just say that the signal traveling thru your speaker wires is traveling at the speed of light....186,000 miles per second. An extra foot of speaker wire on the left mid aint gonna make any difference and it won't add enough length to increase resistance. So....prissy huh?


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## Analog Values (Jan 19, 2017)

I wouldn't have said so a week ago, but I am starting to feel a bit prissy. I need to grab that flagon of ale.......


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## MacLeod (Aug 16, 2009)

Analog Values said:


> I wouldn't have said so a week ago, but I am starting to feel a bit prissy. I need to grab that flagon of ale.......


Yeah leave those panty waist girly men from the home audio crowd and let them sip wine while listening to their $80 extension cords with the magic rocks on them. Come hang out with us knuckle draggers.


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## Alrojoca (Oct 5, 2012)

Depending on where the tweeters are, dash or wired through the doors.

Bi amping will need an extra run of wire from the amp, maybe that is why, he does not want to bi amp them since it is extra work.

I'd say if not bi amped there might be more risk of damage to the drivers.

He is tapping in the factory wire these are the 2 scenarios:

1
If tweeters are on the doors, sail panel etc, he will be forced to run a second line of wire, I would choose the new line to run the woofers, it will be shorter assuming the amp is in the rear part of the vehicle.

2
If they are on the dash area, way more easy, since they won't need to go through the door for the second line of speaker wire, it can be run up behind the glove box, no need to remove the dash, just fish it from the top to the bottom.


Then you have the passive xover location, you may not want them in the doors, moisture, constant banging of the door will reduce the xovers life. Near the amp is ideal, but then if the amp is far behind the run of wire with the factory wiring doubles in length and if it's 18g there might be a resistance issue.
Passives in the dash or kick panel area is also an option if the room allows it, the wire run is the same if the amp is still in the rear area.


That is why if bi amping the factory wire should be used for the tweeters since they need less power and heat to run.


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## Analog Values (Jan 19, 2017)

Thank you very much, Alrojoca! You guys are truly awesome in providing much needed information. For the record, tweeters are in the dash and Phase 1 is just the four channel Kenwood powering all four speakers. Bi-amping won't happen until I upgrade amplifier in Phase 2.

I was going to leave the thread at that, but you're all over my Focal speakers, so I have to ask one more question. Under the Phase 2 bi-amping scenario _(with quality DSP and righteous amplifier)_ how much power is too much? The components are rated 120 RMS - 240 Peak, and the coaxials are 80 RMS and 160 peak. The twist in all this, is that the component speakers are wired at 2 ohms and the coaxials at 4.

My entry level understanding was that we should match amplifier and speaker ratings as close as we can, but it doesn’t take long to pick up on the sentiment weak / distorted power blows speakers, not strong / clean power. People I’ve talked with don’t seem to be too concerned about too much strong / clean power. This sparked some notional thinking on my part about using a four channel amp rated at 150 watts per channel. That might make some since at 4 ohms, but sounds pretty crazy at 2. Would that be delivering something like 600 watts per side? Should I tone this down to a 75 watts per channel amplifier? Even that would be well over the 120 RMS.

What do you guys think? How much is too much? And does the 2 ohm thing strike you as kind of weird? _(Although I'll clearly benefit from that in Phase 1.)_

Thanks!


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## Alrojoca (Oct 5, 2012)

Using 2 channels for the components, makes sense if you are running rear fill, otherwise bi amping you loose 2 channels.


I think your amp puts 100 W at 2 ohms, it will be fine. Many here almost double the power to the woofers, I ran my Morels handling 140W with an amp bridged at 220-240 W same thing now with a set of Hertz HSK XL that handle 120W, as long as you don't high pass them below 80hz and use a stepper slope they can handle the extra power since music is dynamic and he extra power simply improves the peak power dynamics. If you can afford more power great, what you may not want to do is, bridge the amp and connect the 2 ohm speaker load to it.
Assuming we are talking about the same xr400 amp, the fronts will get 100W each, and the rears 75W each. With 2 and 4 ohms respectively


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## fhpchris (Dec 29, 2015)

Analog Values said:


> Thank you very much, Alrojoca! You guys are truly awesome in providing much needed information. For the record, tweeters are in the dash and Phase 1 is just the four channel Kenwood powering all four speakers. Bi-amping won't happen until I upgrade amplifier in Phase 2.
> 
> I was going to leave the thread at that, but you're all over my Focal speakers, so I have to ask one more question. Under the Phase 2 bi-amping scenario _(with quality DSP and righteous amplifier)_ how much power is too much? The components are rated 120 RMS - 240 Peak, and the coaxials are 80 RMS and 160 peak. The twist in all this, is that the component speakers are wired at 2 ohms and the coaxials at 4.
> 
> ...


I have the older KRX2s that were crossed over at 4700hz. I run them active on a JL 300/2v2(mids) and JL 300/4v3(tweeters, and a channel pair for future 3-way) I run an Audison Bit One and recommend them to everyone.

On your question on Amplifier power, I think anything 150 RMS*4 would run them active quite well. You will not need to turn the amp up all the way, and you will have tons of headroom. My mids (in my DSP) are -5db, Tweets -7.5db and neither gain is up near the max. (less than 0DB overlap, set with DD1+). Car does 116DB with no sub with just that one component set in music (turned up all the way). I am probably only using ~80w per channel going to the mids, maybe 20-30w going to the tweeters. Anything in the JL HD600 power range will work perfectly for what you need to do. 6 channels of 150*6 would be nice to run active. I would recommend doing that if you have the budget/space. You could also do two 150w RMS*4 amps (like two JL HD600s) and bridge channels 7 and 8 to a real sub. (ported 8 or something)

You do not need to worry about matching amplifier power levels front and back, because the DSP will take care of all of that. Even if you only run active without a DSP, you can set channel levels with gain.

I would not get an amplifier with less power than 150w RMS*4 for the fronts and 100w RMS *2 for the rear. I would personally want plenty of headroom. Even if you got a huge amp that does 300w RMS @ 2ohm (DC Audio 175.4k, for example) you can just turn the gain down. The headroom would be absolutely great to have. You could simply buy a JL XD 600/6 (or 800/8, bridging the last 2 channels to a sub) and run your whole system with a little amp.

My component set is extremely unimpressive below 90hz or so. I think you should find room in your budget or build to put some kind of sub in there (before waiting for stage 3), even if it is just a ported 8w3 or Rockford P2 or something cheap. I have spent tons of time listening to your component set.... I think you will be pretty happy with everything as long as your install goes well! 



> The primary con I’ve read about Focal is that is has an edgy tweeter (a legitimate concern given the bright nature of digital format to begin with). I may very well suffer tweeter fatigue in Phase 1, but perhaps address it with a Phase 2 DSP. The reason I bought Focal is it seems to be a top brand in my area, and I got a good deal on these particular speakers. I was looking at the flax, but lucked into a highly discounted upgrade. You’ll laugh at this, but my original plan was to start at the front-end, and work my way backwards to the speakers. However, I was convinced by my dealer that any amplification I was looking at would fry my factory speakers, so I needed to start at the back-end instead. Oh well. I don’t know what they’ll sound like, but I got a good deal on speakers that should be of decent quality. Time will tell. One can only do what one can do.


The install matters so much! I would not focus on worrying about a tweeter brightness, because a good DSP lets you control all of that. Even if you run Active without a DSP, you can easily tune everything with just gain. The ES KX2s are bright, but not in a bad way. The big advantage of the DSP is that you can fix all the small issues. Your speakers will be in stock locations and everything will not be perfect...even if you have the perfect speakers! The install matters just as much as the hardware.

I would not even use the passive crossovers. I would probably just buy 8 channels of amplification that was at least 150*6 + 300-600 for a sub and just be happy. You could save a ton of money and space by running this all off one or two amplifiers ( sub included)


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## MacLeod (Aug 16, 2009)

Analog Values said:


> Thank you very much, Alrojoca! You guys are truly awesome in providing much needed information. For the record, tweeters are in the dash and Phase 1 is just the four channel Kenwood powering all four speakers. Bi-amping won't happen until I upgrade amplifier in Phase 2.
> 
> I was going to leave the thread at that, but you're all over my Focal speakers, so I have to ask one more question. Under the Phase 2 bi-amping scenario _(with quality DSP and righteous amplifier)_ how much power is too much? The components are rated 120 RMS - 240 Peak, and the coaxials are 80 RMS and 160 peak. The twist in all this, is that the component speakers are wired at 2 ohms and the coaxials at 4.
> 
> ...


Buy as much power as you can afford. It's not about loudness, it's about be able to reproduce those intricate little details like the sound of fingers plucking a bass string or Diana Krall's little breaths in between vocals. You need power to reproduce those realistically. 

A 500 watt amp isn't making 500 watts all the time. It's like horsepower. Would you say I don't need a V8 because I don't drive over 65? Of course not. That extra horsepower would be great to have on tap when you need to accelerate into traffic fast or pass that 130 year old woman doing 35 down the freeway or when you need to haul a bunch of stuff. Same with a big powerful amp. It's not there to be loud all the time. It's there for when you need it. 

Use common sense with the volume know and pay attention. Your speakers will tell you when they're being stressed too hard. I've seen guys running insane amounts to drivers, like 350+ to mids and tweeters without blowing anything. Wattage isn't just about volume just as horsepower isn't just about driving fast in a car.


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## Analog Values (Jan 19, 2017)

Intricate little details? Won't that be lost at the 16 gauge wire splice point with factory wire?

Just kidding; I'm encouraged to hear a knuckle dragger speak of intricate little details!

Thank you all for the help, and I'm very encouraged by the fact I can add as much clean power as I can afford without worrying about damaging the speakers. Perfect!

Thanks again.


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## MacLeod (Aug 16, 2009)

Analog Values said:


> Intricate little details? Won't that be lost at the 16 gauge wire splice point with factory wire?
> 
> Just kidding; I'm encouraged to hear a knuckle dragger speak of intricate little details!


Well the SQ guys are all about those intricate little details. It's those details that we're all in a desperate and never ending search for.



> Thank you all for the help, and I'm very encouraged by the fact I can add as much clean power as I can afford without worrying about damaging the speakers. Perfect!


Well now let's make sure we're on the same page. You can go stuffing 500 watts to your tweeters, crank it up to max volume and not worry about anything happening. You still have to exercise proper gain settings and common sense with the volume. That's true of even lower powered amplifiers. With those things covered, you're good to go.


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## syc0path (Jan 23, 2013)

Analog Values said:


> May use bridged Kenwood to power Bose subwoofer


Bose speakers typically use non-standard ohm loads (generally 2ohms, but I've heard some mention of 1ohm). Bridging into a 2ohm load is not recommended for the vast majority of amps.


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## Analog Values (Jan 19, 2017)

Yes, what to do with that Bose subwoofer prior to replacing it is a curiosity for me. I contacted Bose to see what it is, with the answer being it's a 5.25" subwoofer wired into 1 ohm, receiving 75 watts of factory power. It may be best to simply have it removed.

And yes, I'm much more interested in protecting my hearing than producing extraordinary sound effects. I'm not prone to reckless behavior.

But I do feel a paradigm shift coming on. My thinking has been SQ resides with class AB amplifiers, but the 'most power I can afford' sentiment may challenge that thinking. I sense an opinion being expressed that I should get over myself, and throw down with a class D amplifier that produces more power. Perhaps it's time to discard my mom jeans, and power up like a real man.


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## Alrojoca (Oct 5, 2012)

class AB amps=big, power hungry or less power efficient.

Some may prefer them for the front stage, and not to drive subs. It can be a controversial topic. No worries class D amps deliver SQ and SPL too


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## Analog Values (Jan 19, 2017)

You all are extremely helpful, as I try to gain my equilibrium in this world. I was about to say one more question, but it seems I will never run out. There is a lot of discussion here about the value of headroom, which I completely understand. However, I'm used to measuring it in a different way. I have a British rack of home electronics, characterized by a modest RMS rating but with monstrous peak headroom. It can handle anything that comes its way, but you wouldn't know it from RMS. Does that play in mobile audio? For example, I was looking around the web and saw some Genesis equipment that caught my eye, thinking it might correlate to my taste in electronics. The RMS didn't blow me away there either, but for some reason (don't remember why) I perceived they had strong peak headroom.

Does this make any sense? I've been poking around the web, not really knowing what to make of what I see.


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## Alrojoca (Oct 5, 2012)

The only thing I can say, is in a car well tuned you will have the music closer and deal with more reflections and other issues, once you have a decent amount of power for the extra headroom.


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## Analog Values (Jan 19, 2017)

Well, my Phase 1 completed this week in *UTTER DISASTER*! As noted above, my plan was to install final configuration speakers with a stop gap amplifier, to be followed by DSP, final configuration amplifier and subwoofer in subsequent steps. However, I encountered *catastrophe* by trying to execute Phase 1 without a DSP.

Things started out well:

•	The molex in my rear door had several empty honeycomb slots, allowing my installer to cut a hole to accommodate the 16 gauge speaker wire without a splice. *Win!*

•	The front door molex had no such empty honeycombs, but there was some manner of grommet that seemed to be placeholder for wiring not included in my truck configuration. Accordingly, the installer cut a hole in the grommet and strung 16 gauge wire without a splice. *Win!*

•	The installer also humored me by cutting the speaker wire in equal lengths. *Style points!*

Then, I listened to the install: all high end with no mid-range or bass…….unrecognizable……….severe degradation of audio quality relative to the Bose system I just replaced! What the……..!

My installer then explained.

•	Without a DSP, they used some manner of line out converter that was still connected to the Bose amplifier. _(It’s a strong demonstration of my naiveté that I didn’t realize this.)_

•	The Bose amplifier had separate channels going to the front tweeters, front woofers, rear woofers and subwoofer.

•	The Bose subwoofer signal was left in place going to the factory subwoofer, and the rear backfill woofers received a feed with the full frequency range. So far so good.

•	You’ve probably figured it out by now, but that left two Bose amplifier feeds to choose from in channeling music to the front component speakers. They are not bi-amped at this time, so only one feed could be used to power the front tweeter / woofer component set. The woofer signal had no high end at all, so the installer used the tweeter feed to power my front components. Disaster! My prized Focal component speakers are being powered by the Bose tweeter feed comprised of nothing but high frequency. Unbelievable…………….!

If I seem a bit crestfallen, you should hear my wife! Here I go expending political and monetary capital on a stereo upgrade, and it sounds far worse than before I started! To say my credibility has taken a hit would be an understatement. _(Are you familiar with marital discord?)_

I’m now in need of a little help from my friends, as I’ll be posting a new thread asking for Phase 2 recommendations on a DSP and final configuration amplifier. I perceive this to be an awkward time to buy a DSP, as we seem to be on the verge of a new generation. The Zapco HD/DSP-Z12 V PRO and Audison BIT One HD seem yet to be available, and I’m very interested in achieving 24 Bit playback capability. Oh well. It appears Phase 2 will happen a bit sooner than I anticipated.

By the way, here is what the installer did according to his own judgment:

Slope: The high-pass crossover slope is12 dB/octave. A switch on each crossover allows you to choose between 18 dB/octave and *12 dB/octave *slopes for the high-pass crossover. Another switch allows you to choose between _*12 dB/octave *_and 6 dB/octave slopes for the low-pass crossover. The crossover point for both is 3,000 Hz.

Tweeter Level: A three position switch on the crossover allows you to adjust the output level of the tweeter to _*-3 dB*_, 0 dB, or +3 dB.

Tweeter Shelf: Another switch on the crossover turns on/*off* a high-frequency boost, designed to improve definition.


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## badmotorscooter (May 22, 2009)

Rip the Bose crap out asap. Get a new head unit because you will fight with the Bose amplifier eq for eons. I know DSP's can sum multiple input channels but you can not fix the existing phase shift. I tried keeping the factory head, but soon ripped it out, and now life is much better. The factory Bose system has a 350Hz high pass on the dash speakers, an a 350Hz low pass for all the door speakers. There is a 50Hz bump in the low end, and a 25Hz subsonic filter that you can not defeat or "eq out".


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## Analog Values (Jan 19, 2017)

Man, replacing my factory head unit is tough love, badmotorscooter. I'm not ready to go there quite yet, but you may have added a new phase to my plans.

Tough road.


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## badmotorscooter (May 22, 2009)

Analog Values said:


> Man, replacing my factory head unit is tough love, badmotorscooter. I'm not ready to go there quite yet, but you may have added a new phase to my plans.
> 
> Tough road.


You can get your factory head reprogrammed $100-$200, but not sure how that applies to the Bose units, it should not matter. All eq is in the AMP at the back wall, but GM left no wires for the factory "preamp" head as it wasn't needed for Bose installations. I almost did this, but I can't live off playing lossy file types either.


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## brumledb (Feb 2, 2015)

I had the radio reprogrammed in my 2014 Sierra SLT and it works fine. I have several different sources mainly use Tidal from my phone and ALAC from iPod. But I also use 320kbps from flash drives and sd cards. 


Sent from my iPhone using Tapatalk


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## Alrojoca (Oct 5, 2012)

Sorry to hear it. That is the issue with some factory systems. I thought eventually the DSP will be added, factory amp removed or replaced, but the head units have some filtering and EQ that may be hard to correct or makes things impossible.

A good shop or installer should know this before doing the work, or at least be flexible if the sound is 2 times worse than before.

Another option if you want to keep the factory HU, is to install a single din HU and new amp, in a different location and just connect very small cheap speakers to the factory system for gps or other stuff, it will depend on the room available, sacrifice some space, glove box etc. You can get a single din HU for $100 with 6 channels, BT, T Alignment, USB and High pass filter, that is all you need to enjoy those Focal speakers


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