Bose Bypass possible solution

[HIBUHIBU]

Yes, indeed Bose audio is pretty damn terrible.
Reproduction of sound as intended by producer/sound engineer?
They can kiss my butt because Producer/Engineer do not listen with 9 or more speakers when they record their music.
CD is stereo because it is recorded with 2 differenct signals Left/Right only.
Having more speakers only cause phase issues.

But still like 1sty said, unless you are keeping your stock bose amp, you are really degrading the quality of the sound even further. If you do want to improve the sound quality, you really need to change the whole system and tune each equipment so they work well with each other.

Replacing the Bose speakers with aftermarket speakers would not yield any problem, however, if you replace them with 4ohm speakers, then Bose amp's power output decreases in half.(Look into Ohm's law for this)

However again, running bose speakers(2ohm speakers) directly with your new aftermarket head unit is not only a down grade, but very stressful for your new CD player.

None of the people here do not need to listen to me. I am just trying to hep and share some info/knowledge on what I accumulated from years of car audio experience. To give you an idea, I have done numerous installs involving fiberglass, MDF, etc etc. I am actualy currently in the process of custom install for my CX-7 as well.

Also, I can definitely tell you guys that 1sty DOES know what he is talking about. Just keep in mind that me and 1sty has absolutely no reason to stop you guys from getting something better. I personally love to share my limited info/knowledges to my fellow CX-7 owners.

I do not care what other audio shops tell you online/offline because from my experience, 95% of the shops do not even know what the heck they are talking about. Heck, most of them do not even know what phase is. Sure most of them can make your audio look nice, but you get an audio system to listen to the music. Not to look at it.

Do whatever you need to do, but please keep in mind that non of us here has any intention of harming you/your car. We are all here to help each other out. Aren't we?

Hope this helped.

 

[CX-7owner]

To just assume that the speakers sound terrible is just what it is, an assumption, unless you've heard it you can't really say it was a downgrade. The Bose Amp could have been holding the speakers back, but to assume that the speakers only sound good with the Bose amp, is not ok. Also replacing the Bose speakers with the Bose AMP could be a possible downgrade, because you would need to replace them with 9" shallow woofers up front, the dash speakers, that all have a low impedance, what a PIA.

 

[HIBUHIBU]

Sigh....

I did not assume anything here. I only explained why getting a new head unit and using it to powering the bose speakers directly would be a bad idea according to "Ohm's Law"

Yes, you are correct that it might sound even worse when changing all the speakers and amps. In fact, most systems that were installed on the shops actually do sound worse than OEM premium systems.

When we talk audio, we call it a "system." The reason is because musical reproduction is done through integration of various differennt components such as the source, source unit, amplifiers, crossovers, speakers etc.
Simply dropping high end audio gears into a car does not create a HI-Fi sound at all since all the individual equipments are made with different philosophy and goals. However, they do come with some ability to integrate with each other, and proper installtion and tuning makes them a what we call a Hi-Fi Audio System. Most SQ oriented systems require hundreds hours in preparation, installtion, and tuning(this literally takes as long as 6 months or longer). It is a known fact that crappy speakers installed correctly(integrity wise. It does not even need to be fancy install), and tuned to best of its ability, sound better than $1000 speakers that were installed poorly and tuned incorrectly. Therefore, to achieve a Hi-Fi system, you need to have a scientifical approach(objective) and reality approach(subjective) at the same time. It is a PITA to have a great audio system since it requires so much time and money. For most people, it is not even worth it since they are probably better off with OEM premium systems since they are mostly tuned to best of its ability(OEM spends hundreds of hours tuning alone).

What I did earlier was to give a scientific approach based on Ohm's law. I only tried to explain what is possible(or recommended) and what is not achievable. I don't think I assumed anything here.

I hope no one was offended here by my comments earlier and now. I only tried to explain.

Hope this helped.

 

[CX-7owner]

LOL who would be offended?

 

[1sty]

To just assume that the speakers sound terrible is just what it is, an assumption, unless you've heard it you can't really say it was a downgrade. The Bose Amp could have been holding the speakers back,

NO it couldn't
Bose does not design systems that way. bose is 90% electronics and 10% drivers. Remove the electronics and you have crap.
They are matched together by engineers. Its a bit arrogant to think that a basic peice of crap head units amp would be superior. In fact it would not be. Even if it were "holding back the speakers", then you would need a more powerful seperate amplifier, not a POS head units amp. yes all internal amps to head units are crap by comparision to a decent seperate amplifier.

Replace the speakers AND the Amp or replace neither. Doing otherwise is a waste of time and money.

You can easily enough replace any speaker in the car with common aftermarket gear. Adapter plates are easily made.
I would not even bother with the dash speakers. I would just disconnect them. You can make a good set of components in the doors sound a bejesus better then a set of both dash and door speakers which will be just noise as they will interfear with each other.

 

[CX-7owner]

Ok Then.(bicker)

 

[coltrane]

I just want to be able to use my alpine head unit because #1 my existing bose radio does not support mp3 #2 the alpine has back up camera #3 it integrates with my phone #4 it has dvd player $5 better nav option then mazda #6 I can run a game console to it $6 it can control multiple video outs where one person can watch a dvd in the rear and the other can be watching sat tv lets say.

AMEN! This is my thoughts and reasons exactly! Well, other than the game console thing. These are the reasons I want to add an aftermarket Navi HU, I want to keep the Bose speakers, though, its my wife's car and she says she's very happy with them, and from the time I've been in it they sound fine to me. So can I just replace the stock HU, use a wiring harness to connect, and keep both the Bose amp and speakers? That's what I've been unclear about to this point so I'd like to hear from 1sty and HIBUHIBU on that. I believe I can from the what they've said so far but I want to make 100% sure before I proceed. Thanks!!

 

[07LiquidCX7]

1sty and HIBUHIBU, are correct. If you want to replace the head unit to upgrade the features... then you need to replace the stock amp AND speakers, or neither. If you bypass the factory amp and power the Bose speakers with your head unit you are not only losing output, but also causing undue wear to the internal amp of the head unit. I prefer head units to not even come with an internal amp, but just a good set of pre-outs, like 5v-8v pre outs. I will never use an internal amp on the HU to power speakers unless specifically asked by a customer. Think about it, the highest rated internal amp is 50x4 (peak). That's like maybe 20-25 watts RMS. Any aftermarket amplifier (and the Bose one) will beat that and sound alot cleaner.

Just wanted to reiterate what I thought were the correct ways to do it, to back up 1sty and HIBUHIBU. The Bose speaker system does not sound horrible as a stock premium system... but when compared to solid aftermarket equipment (even entry-level stuff) it does sound terrible. I have yet to hear a factory system that sounds as good as a complete aftermarket install. They are getting rediculous on the amount of speakers and DSP (digital signal processing) going into it, which is leading them farther from a TRUE Hi-Fi audio setup. Now what they are good for is watching movies, since they are coming with 5.1 and Dolby processing now. But again those DSP features are not necessarily very good for reproducing clean music. Again JMHO.

 

[nikedout]

Bose System

I just contacted PAC and they said that there is yet to have a Bypass made for the New mazda 2007 CX-7... I am going to send them out my stock head unit as well as amp so that they can go ahead and make one and get it into production for the new year. Thanks for the tip...

 

[CX-7owner]

If the internal amp makes 25 watts RMS@4ohm, then @2ohm, aren't you looking at 45, 50RMS? Is the Bose system is rated at peak power? You're looking at 180watts RMS? I prefer Digital Signal Processing over regular untouched stereo sound, It sounds better In most cases.

 

[07LiquidCX7]

If the internal amp makes 25 watts RMS@4ohm, then @2ohm, aren't you looking at 45, 50RMS? Is the Bose system is rated at peak power? You're looking at 180watts RMS? I prefer Digital Signal Processing over regular untouched stereo sound, It sounds better In most cases.

Audio in most cases is a matter of personal taste. In this case you made the right decision for your listening preferences by sticking with the Bose amps. For hi fidelity musical reproduction most ppl would prefer no DSP at all. For example, my head unit (Kenwood x898) has all kinds of SRS, WOW, and DSP processing, but I run with them all off and tune with the amps. Most of the installers I know do the same. Again it's personal taste though, so there is no right or wrong way.

Technically, yes... the internal amp would make 45-50 watts RMS. The problem is that it wouldn't make it for a dependably long time (years) because the internal amps of head units aren't designed to run at 2ohms, they are strictly 4ohm stable jobs. Now if you never listen to your music very loud you MIGHT never have a problem because you aren't pushing the amp do deliver the 50 watts of power. But I bet the internal amp would still get pretty hot from being forced to run at 2ohm and this would intern shorten life. Now if your installer got clever and installed the factory speakers wired in series to bring 2 2ohm speakers up to a 4 ohm load then you would be fine. But you would lose fading/balance capabilities.

Just as a simple comparison... look at aftermarket amps like a Kicker 4 channel amp that delivers 50 watts x 4 @ 4ohm RMS. The size of it is at least 12" long by 2.5" tall x 8" wide. Plus the heat sink on it is substantial in order to disperse that much heat. Now try to imagine a head unit supplying the same amount of power in a much smaller package... it's thermodynamically impossible.

 

[HIBUHIBU]

I completely agree with you 07LiquidCX7.
I think you explained everything that I have been trying to explain in better words. Thank you.
DSPs are somewhat cheaply available these days, and many OEM or aftermarket companies definitely do take advantage of it.
It could be good or bad, BUT it depends on what kind of DSP we are talking about here.

Let's first define what the true purpose of Audio System. Shall we?
Hi-FI Audio started and still is to reproduce the music originally as intended.
This means that you should hear "exactly the same thing" that you would have heard if the singer was right infront of you at the recording studio.
You want to hear the MUSIC, NOT THE SPEAKERS.

Contrary to what people believe, Cars are terrible for Hi-Fi stereo system.
The reason is because we are first of all, skewed to one side(we are seating on the left closer to left speaker) and sound reflects too much which causes phase issues and many others. I can probably list hundreds of reasons why car is such a bad environment for true Hi-Fi.

So to get around all these obstacles that comes with harsh environment of automobiles, we need to do 2 things.
1. Installation to get around the issues as much as possible. (You don't install your stereo equipments to the car, but you install the car to your stereo. Make sense?) Few example would be kick panel, dynamat, cutting new location for the speakers, angling the speakers, closed cell foam, etc etc etc.

2. After you have done all you could do(or willing) to do the best installtion as possible(fitting your car to the stereo), now you are ready for the DSP.

Type of DSP Bose often uses is to create a music of its own. For ex, Center Point. It creates 5.1 system out of 2.1 system which is our CDs. Remember, CDs were never recorded with 5 or 6 different signals, it comes with 2 signals Left/Right. Just by doing this, they are already going against the true purpose of Hi-Fi system. Like I said before, the goal is to hear the MUSIC, not the speakers. You do not want your system to add or delete anything in the CD.

Another DSP Bose often uses is automatic equalization. you cannot turn this on or off, but you can listen and tell what is going on. First, turn your Bass to 6+ and Trebal to 6+.
Now put a cd that bumps and slowly increase the volume of your cd player. As you increase the volume the bass, mid, and trebal should increase as well up to about volume 26. keep on increasing the volume from there, and you will notice that the only part of music that gets loud is the mids. Bass and trebal stops increasing with rest of the music. As you can HEAR, your system is automatically Equalizing the music so it does not distort badly.(since stock bose subs do not really have the ability to play that loud)
Again, this type of DSP is bad because your system should reproduce the music in linear manner. The only thing that should change as you move the volume knob is, again, volume throughout the music.

Now what would be a good type of DSP then? It is type of DSP that will help your to defeat or move around the harsh environment of your car. Example would be a "Time Alignment."
"Time alignment" is a DSP that gives you the ability to delay the sound coming from your speaker by miliseconds. Why do we need this? Because, in a car, we are not in same pathlength between you and the speakers since you are seating closer to left side of the speaker.
When they record you favorite CD, they assume that you will be seating perfectly in front and center between the speakers(Left/Right) creating the perfect 60 degrees.
So by delaying the sound coming from the left speaker by miliseconds, hence, by making the sound coming from the left and right to reach you at the same time, you are one step closer to listen to music as it was recorded. Like LiquidCX7 mentioned, even this DSP, many HIFI people do not like to use too often. Many of them would rather go around the same issue with a even better/crazier install.

I agree that BOSE system uses too much DSP. It is too heavily DSPed that I feel like I am listening to speaers, not music. It sounds fine and I believe most of people will be happy with it, but it is still far from what True Hi-Fi supposed to be.
We need DSPs in car audio to get around environmental issues, but I would have been happier if BOSE used something more useful such as time alignment. I also wish they didn't DSP too heavily.

As for PAC interface, all they are going to do is find out what type of pin plug BOSE has, and put the matching male/female plugs on LOC so that a customer does not need to cut any wires. They want to sell it as plug/play
Any shop with decent skill will be able to interface your BOSE and Aftermarket Headunit using LOC.

Coltrane,

As long as you keep your BOSE amp with Bose speakers, you will be fine. Any decent shop will be able to do it for you. It should take them less than an hour. The BOSE amp is located right behind the left side or rear seats. All you need to do is remove the trunk cover and it's right there.

This thread has been interesting and fun.
Let's keep it rolling.

 

[07LiquidCX7]

^Exactly... lol I get to talk mobile audio on my e46 bmw boards all the time, but this is the first time on the CX-7 board.

I agree, time alignment (my head unit offers it) in most installs is the only DSP that should be used due to the nature of seating and speaker positioning (unless watching a movie/playing a video game). I don't typically use it because then either the passenger or the driver gets screwed. LOL so I usually tune it so that they both hear the best possible audio. Neither will be perfect, but again the best possible. ROFL, the ppl I really feel sorry for are ppl in my backseat. I don't care how the music sounds to them at all Then again I don't typically ever have ppl in my backseat.

 

[HIBUHIBU]

I am glad to see audio enthusiasts in CX-7 forum as well.
For audio forums, I am mostly at www.diymobileaudio.com or www.elitecaraudio.com

Hope what I said earlier was not too confusing for everyone.
I will be doing install for my CX-7 very soon. I will try to take few photos and see if I can show you guys how to tap into bose system.

Hope this helped

 

[CX-7owner]

CenterPoint is a horrible DSP for taking stereo to 5.1 surround, you can always hear which speakers are playing, which is not the intent for "surround sound". Now the Digital Dolby Pro Logic Surround in Volvo S40 on the other hand, is very good, but only really for the two people in front. And yes most new stock systems have limiters in them, even the crappy standard system in my CX-7 had it.

 

[07LiquidCX7]

I will be doing install for my CX-7 very soon. I will try to take few photos and see if I can show you guys how to tap into bose system.

Just finished my "simple" install of a custom sub box that bridges across the 2 rear strut towers for a 12" JL Audio 12w1v2-4. I will post pics as soon as I take them when my wife gets home from work. Came out really nice. I will eventually build a CarPC into this car with a touch screen but for now the wife just wanted some added bass to listen to. Came out REALLY nice. We are both happy with it.

 

[1sty]

If the internal amp makes 25 watts RMS@4ohm, then @2ohm, aren't you looking at 45, 50RMS? Is the Bose system is rated at peak power? You're looking at 180watts RMS? I prefer Digital Signal Processing over regular untouched stereo sound, It sounds better In most cases.

If the laws of the physical word did not include thermodynamics then yes. However NO amplifier can possibly double its power output when it goes from 4 to 2 ohms. It will loose power to heat. If the amp is designed for 4 ohm loads and not 2 ohms AND not specificly labeled as 2 ohm stable then it will loose alot of power to heat. The head unit will likely be running at 35%-50% so maybe you would get 35 watts rms. THink the japanese amps of old; a 2 channel amp that was 50x2 would only be 130-150 watts when bridged but by the numbers it should be 200 watts. That again is not physicly possible but an amp designed to run at that impedance will do a better job.

DSP is too broad a term to really know what is going on. It can be as simple as a high pass crossover. DSP is even the new meathod of equaliztion so its not all bad. We commonly use DSPs from clearone and some other brands all the time for commercial sound installtions.

That said, if the CX-7 is like the mazda 6's bose system then there is no DSP, it is all analog circuitry to complement the car and the speakers. Part of that is the volume attinuation that will lower the base and treble at higher volumes and raise it at lower volumes. This is why tapping the outputs of the amp for a sub amps signal is a major waste of time.


Just to state it AGAIN
- Replacing the head unit is fine, have fun, no problem.
- Replacing the head unit and bypassing the amp while leaving the factory speakers is bad idea.
- Replacing just the speakers is a bad idea. Bypass the amp and add a headunit to do this. However the factory system will be superior.

 

[07LiquidCX7]

Just to state it AGAIN
- Replacing the head unit is fine, have fun, no problem.
- Replacing the head unit and bypassing the amp while leaving the factory speakers is bad idea.
- Replacing just the speakers is a bad idea. Bypass the amp and add a headunit to do this. However the factory system will be superior.

^And done... (drinks)

Yes DSP can be a wide variety of things, including EQ. AudioControl and a few others make some very fine Digital Eq's... expensive too But a great tool for getting a flat signal (original, as recorded) with no peaks/valleys.

Generally speaking though DSP's are of the signal altering sort which is why I don't use them, or like them for musical reproduction. I want to hear it as original as possible.

 

[CX-7owner]

Other sources are telling me that only 1ohm would overheat, not 2ohm. ??!confusing!?? (confused)

 

[HIBUHIBU]

From what I understand, BOSE head units in CX-7 is made by Clarion and it DOES pull out flat signals. I believe it is very similar or same as mazda 6. All the DSP are done at the amplifier.
So if you are going to keep the BOSE Cd player and get aftermarket equiments, it will be fine as long as you tap it in at the input signal.
This is exactly what I am going to try. I am going to tap in my "soon to purchase" RF 3sixty.2 for aftermarket equipments. I will let you guys know how it turns out as soon as I finish.

I am personally a big fan of DSPs that help us get the flat signal and defeat the pathlength difference in a car. I believe that if used "properly" after a proper installtion(even more important), it could help us to get the true HIFI. It is a tool with blades on both sides, it is only as good as the installer/tuner's ability IMO.

CX-7=Love,

Any amplifier will heat up more as you go with lower ohms. Given the same amplifier, it will heat up more if you go from 8ohm to 4ohm, 4ohm to 2 ohm, or 2ohm to 1ohm.
There aren't too many amplifiers out there that can really handle 1ohms too well. I know old school Sony ES amplifier did. Most of the amps out there are not 1ohm stable.

If you use decent quality external amplifier with good heat sink and cooling ability, most of the time, you will be fine with 2ohms.
However, internal amps inside an aftermarket cd player is, again, not designed to run 2ohms(does not have good cooling ability such as heat sink, big fan etc etc) and it will be way too stressful for the internal amp. It also starts to sound "dirty" as it stresses more and more. (For ex. 75watts of power played by an amp rated at 100 RMS sounds dirtier than 75watts of power played by an amp rated at 200RMS. Of course, given that everything else stayed the same)
So with an external amp, you will most likely be fine to run 2ohms. With an internal amp of cd player, it will be stressful.
With 1ohm, pretend it is your birthday because you will see smoke coming out from the cd player.

Hope this helped.
This has been fun.

LiquidCX7,

Could you post a picture of your new set up?