I need the true answer

[chanman859]

I recently purchased an 04 G35 coupe w/ bose system... traded in my 02 bmw 325i.

In my bmw I had the dice ipod connection with stock head unit etc. in the G coupe I really don't like the looks of the cassette player, and want to upgrade it to the Pioneer AVIC-F700BT. Mainly for the ipod/SD/ USB availability. Originally I didn't care much for the navigation as I already have the Garmin Nuvi 760, but the price difference for GPS vs no GPS is not much, so I might as well get one with the GPS.

I went to a couple Car Toys stores here in Seattle and they were quoting me for near 2000 to 2800 for installation etc. One of the installers were telling me that because I have the BOSE Sound system, If I was to change the head unit, I would have to change the speakers and amplifier as well. He also said that it was because the OEM speakers are running off a different ohm output and it would not match with the aftermarket HU.

I want to know if this is true? do I HAVE TO change everything? Can I not run off the HEAD unit and just use the OEM speaker, amp, etc? I don't want to spend more than 1500 USD. (that's including tax, install etc.)If It was to cost more than 1500, I will look into just an Ipod integration through the SAT as I have read in the forums.

Thanks for reading. I will look forward to your replies.

[pfarmer]

I recently purchased an 04 G35 coupe w/ bose system... traded in my 02 bmw 325i.

In my bmw I had the dice ipod connection with stock head unit etc. in the G coupe I really don't like the looks of the cassette player, and want to upgrade it to the Pioneer AVIC-F700BT. Mainly for the ipod/SD/ USB availability. Originally I didn't care much for the navigation as I already have the Garmin Nuvi 760, but the price difference for GPS vs no GPS is not much, so I might as well get one with the GPS.

I went to a couple Car Toys stores here in Seattle and they were quoting me for near 2000 to 2800 for installation etc. One of the installers were telling me that because I have the BOSE Sound system, If I was to change the head unit, I would have to change the speakers and amplifier as well. He also said that it was because the OEM speakers are running off a different ohm output and it would not match with the aftermarket HU.

I want to know if this is true? do I HAVE TO change everything? Can I not run off the HEAD unit and just use the OEM speaker, amp, etc? I don't want to spend more than 1500 USD. (that's including tax, install etc.)If It was to cost more than 1500, I will look into just an Ipod integration through the SAT as I have read in the forums.

Thanks for reading. I will look forward to your replies.

I am not sure on this however I remember reading another post here that basically did the reverse, that is they replaced the Bose amp and speakers and ran the new amp off of the original head unit.

If this is the case then it seems reasonable that you could keep the Bose and current set of speakers.

Perry

[smockers83]

The Bose speakers run at 2 ohms rather than 4 ohms, which is essentially the standard in automotive audio. In order for the head unit to work, you have to bypass the factory amp. This means that the speakers will be running off of the new head unit and not the amp. So if the HU is stable down to 2 ohms, then sure you can keep everything the same, but you would not have to replace the amp.

With the F700BT, you can hook up a sub running at 2 ohms when you bridge the two rear channels, but whether you can run a whole system at 2 ohms, I'm not sure. I would call Pioneer and ask them directly.

[chanman859]

thanks for the reply. I have just contacted Pioneer by e-mail and will be waiting on their reply.In worst case scenario, I would not mind spend a little more money to just get the head unit to power the current speakers and get an amp to power a new sub. I really don't want to change the speakers at this time as it will cost too much money.

[pfarmer]

The Bose speakers run at 2 ohms rather than 4 ohms, which is essentially the standard in automotive audio. In order for the head unit to work, you have to bypass the factory amp. This means that the speakers will be running off of the new head unit and not the amp. So if the HU is stable down to 2 ohms, then sure you can keep everything the same, but you would not have to replace the amp.

With the F700BT, you can hook up a sub running at 2 ohms when you bridge the two rear channels, but whether you can run a whole system at 2 ohms, I'm not sure. I would call Pioneer and ask them directly.

I would think this would only be the case if you are using the built in amp of the Pioneer head unit rather than its audio outputs from its RCA type of jacks. The last depends if it sports RCA outputs. I have installed several Pioneer head units and all of them had built in amps and RCA outputs. It appears this unit also supports this in the way of Front, Rear, and Sub.

I haven't torn into my Bose amp yet, but an initial look at the pdfs is that it appears to be able to accept a 'sound signal'. If that is the normal signal levels present from the Pioneer RCA outputs then the Bose may just be able to stay in place if desired. In this case 2 ohm versus 4 ohm means nothing since it is the Bose amp that would be driving the stock speakers.

If necessary you could impedence match the speakers however my experience with stock speakers is that if you are going to that trouble then you may as well replace the speakers as well, you have already done the hard work of accessing them. Now if going this far I would also bypass the built in 50w x 4 in the Pioneer as well and put in an after market amp. You can go in different directions here, in my last project I went with a pretty much plain jane Pioneer head unit and then went with (2) 5 channel amps, one channel each for FR, FL, RR, RL, and sub. In my case each channel is rated at 100w rms.

However this ends up possibly out of the poster's price range, I ended up with close to $2000 with doing the install myself.

Perry

[chanman859]

Here is the reply I recieved from Pioneer:

Thank you for contacting Pioneer Electronics, Inc.Our unit will not support 2 ohm speakers. You might check with your dealer/installer, to see if they have an adapter to allow the factory speakers.

[pfarmer]

Here is the reply I recieved from Pioneer:

Thank you for contacting Pioneer Electronics, Inc.Our unit will not support 2 ohm speakers. You might check with your dealer/installer, to see if they have an adapter to allow the factory speakers.

However their unit appears it will support another amp that could support two ohm speakers.

Assuming you like the current speakers then you have a couple of options. If the Bose accepts standard audio signal levels then you may just be able to use it by connecting it to the Pioneer head unit. If not then you could pick up another amp that supports 2 ohm speakers. This would allow you to simply replace the amp rather than digging into the doors, etc. for speaker replacement. This may actually be cheaper than speaker replacement. You could also impedance match the speakers, possibly right at the connections at the output of the Bose unit.

The Pioneer unit (according to Pioneer) will only not support 2 ohm speakers if they are being directly driven by the Pioneer head unit's built in amp. To the Pioneer head unit the speakers don't make any difference if being driven by another amp.

Perry
Modified by pfarmer at 7:19 PM 12/31/2008

[tollboothwilley]

here is what I did...

I had the BOSE stereo with Navigation also.

#1) you need a dash conversion kit#2) New stereo head unit (it can be single or double din with the kit)#3) I ran an aftermarket amp for all the speakers and rewired them all. This way when I change out to aftermarket speakers it will be a direct swap.

I also have subs, so I have another amp, power cap and that all setup in my trunk.

the regular stereo and bose stereo are not "interchangeable" without some work that is worthless.

You should be able to do all that for less than $1500 by my calculations. I do all the work on my car. I don't like others doing stuff

[chanman859]

So in the end I ended up purchasing the Pioneer AVIC-F90BT and just got it installed today. I kept all the speakers and everything... everything works fine: iphone, ipod, steering controls, the original sub/speakers, bluetooth etc. It end up costing around 1500 for everything including an installation from car toys.. I may have paid more than what I should have, but it only took 2 hours and I didn't have to mess with anything so I guess it's a win win situation... The only thing I want to change to the HU is to bypass the break, I was reading the forums on avic411.com and there's photos and instructions to change directory in the firmware for mute and also information to just ground the parking wire while I drive and the passengers can play with the navigation/dvd features...

[smockers83]

Ooo, good choice with the F90BT, that's the one I've been researching and highly thinking about purchasing. Did they bypass the amp when they installed it, do you know? And you should post up pictures of it installed. We love pictures here! How flush does it sit in the dash?

[chanman859]

I'm not really sure if you can see these or not...

Before:



After:

Playing What happens in vegas:

and different angles to see if it's "flush"





I'm not sure if they bypass the amp or not, but I do remember they telling me they added some sort of equalizer to connect to everything...

Playing with it more... there is some delay with the steering wheel buttons.. then again it's not really needed since the buttons are so much closer now.. and also with voice recognition it's easy to find the songs you need.

[smockers83]

Very nice, sir, very nice.

[chanman859]

will you be getting one, smockers?

[smockers83]

I got the OE double-din conversion kit for Christmas. With those pictures, it sits pretty flush, which is important to me, so you just sold me on it. Thanks.

[chanman859]

haha. np... upload some photos when you get yours finished! =)

[Hookm36]

I'm a little late on this thread, but please, please correct me if I am wrong. I just purchased a double din dash conversion kit, and I am about to purchase a head unit. Will not any head unit simply work with my factory bose speakers ? From what I read, the head unit MUST support 2 OHM speakers right ? Really needing an answer, dont want to purchase something only to get a headache later.....

thanks

[smockers83]

Yes, because you need to bypass the factory amp. With the Bose system, the speakers are rated at 2 ohms so since the head unit will be running these directly, you need something stable down to 2 ohms. Otherwise you can either buy new speakers as well or put resistors in place to bring the resistance placed upon the head unit up to 4 ohms.

[G_whizz]

Nice to see ya around Hook!

[Hookm36]

Good to be back Whizz.......have been gone during football season, but its time to start working on the G again !!!

Ok, Audio equipment isn't my specialty, so forgive me. So I can........

1) purchase a HU that supports 2 OHM speakers, and not have to do anything special ? (although it sounds like this might be rare?)

2) bypass the factory amp (would this require re-running all speaker wires from each speaker)

3) Or buy any head unit, and just add resistors (not really sure what or how to do this)

bottom line, I want to be able to purchase any head unit, and use the same factory speakers...........don't want to spend a arm and leg, and possibly do this my self.

I have changed out head units before, but it has been a while......

[smockers83]

If you were to bypass the factory amp, it would just be with a wire harness to connect the amp input and output together. No rewiring necessary.

I'm sure you could find resistors to put inline somewhere to up the resistance. I personally haven't done it, but I'm sure it can be done.

Or you could buy an amp on the cheap side and run pre-outs or something.

If you were to test the voltage coming out of the stock head unit to the factory amp, if they were close whether it was the high- or low-level output, you could wire up a harness of some sort and use the factory amp, therefore negating to have to bypass it or install inline resistors.

I think the easiest way to do it would be to just replace the speakers or get an amp stable at 2 ohms.

[pfarmer]

If you were to bypass the factory amp, it would just be with a wire harness to connect the amp input and output together. No rewiring necessary.

I'm sure you could find resistors to put inline somewhere to up the resistance. I personally haven't done it, but I'm sure it can be done.

Or you could buy an amp on the cheap side and run pre-outs or something.

If you were to test the voltage coming out of the stock head unit to the factory amp, if they were close whether it was the high- or low-level output, you could wire up a harness of some sort and use the factory amp, therefore negating to have to bypass it or install inline resistors.

I think the easiest way to do it would be to just replace the speakers or get an amp stable at 2 ohms.

Actually it is a little bit more complicated than just adding resistors inline. You are not after resistance matching, you are trying to match impedance, using either impedance matching or impedance bridging. In the case of the Infiniti Bose, from what I see without looking at the speakers themselves is that you are looking at speakers with 2 ohm impedance. However it may be worth looking at the speakers themselves as this may not be the case at the inputs of the various speakers, but at the inputs of a cross over network. On the schematics I have seen I don't see cross over networks, but that doesn't necessarily mean anything and that could vary based on year.

Perry

[Hookm36]

sounds like easiest way would be to just bypass the amp with a harnest, but the "best" way to just purchase new speakers correct ?

[smockers83]

It would seem like it to me. Sounds like pfarmer has some electrical engineering experience. Bose is pretty well known for using components rated at 2 ohms in order to get more power out of a low-power system, so I don't think there are any crossovers or differences in how it's wired compared to the non-Bose system.

Impedance is analogous to resistance, it's the same thing.

[pfarmer]

sounds like easiest way would be to just bypass the amp with a harnest, but the "best" way to just purchase new speakers correct ?

This may vary by year. From what I see the BOSE directly drives the speakers without any cross overs, etc. If this is the case and you decide to keep the original speakers then it looks like you can bypass the amp and impedence match or bridge as necessary. However it may be best to replace the speakers - my experience is that the stock speakers in most autos are very marginal to start with, especially quality of materials.

At the same time depending on the vehicle you may want to also upgrade the wiring to the speakers, which can either be a fairly simple job to one much more complicated, such as those vehicles where the speaker wiring runs into the doors in plastic type molded path ways from the body along with the wiring for mirrors, windows, etc.

Now if the the Bose amp accepts standard input levels and you are satisfied with the sound, than the easiest way would be to leave it in place and drive it with the rca outs from the head unit. One of the failings I see with the stock Bose unit in my 2008 is the lack of equalization control, which you should instantly gain an improvement in almost any head unit.

Perry

[chanman859]

I think is always nice to buy new speakers etc. since you are already taking everything apart, but with that is cost. if you are already spending around 900+ for a HU and other materials to make it work, it can be quite costly!

[pfarmer]

I think is always nice to buy new speakers etc. since you are already taking everything apart, but with that is cost. if you are already spending around 900+ for a HU and other materials to make it work, it can be quite costly!

But then I think that may be the point. For around $300 for both sets of doors in a 4 door you can replace those speakers with something far better than factory. Just take the material for the cones as an example. I find the factory cone material will degrade in many cases after a fairly short time compare to most after market speakers. If you bypass the factory amp then you can easily drive them in many cases past their capabilities. Of course at some point you have to pull the plug on the cash flow, but one needs to decide what the priority is since any weak link in the chain sets the limit of the performance of the entire system.

If you can keep the Bose amp then you at least have a system that is matched with the benefit of a much better equalization in most case due to the enhanced head unit. I still can't find a good reference to the inputs to the stock Bose as far as signal levels. But if you have to bypass it then you really need to consider the benefits to be had with much better speakers, especially those easier to reach. And while at it consider better door insulation as I find that a somewhat sore point in my 2008, even the factory speakers can make them buzz fairly easily.

Perry

[chanman859]

300 isnt much more but at same time i dont think it makes much difference... ive tried that in my altima back in the day.... i think to hear a significant change in sound quality, really shoudl just get an multichannel amp and get those component speakers! those have a HUGE difference...

The altima that i mentioned, was my very first car after getting my license... I ended up with alpine HU, and changed the front and rear speakers running with a 4 channel amp and also with a mono for sub... I really don't think those speakers did much good, but while running the wires through everything i thought it was worth the change...

When my friend put in those component infiniti's in his car and some of that dynamat you can hear a big difference, then when he upgraded them to component focals, it was a greater difference!

I understand your point is while you are already running something and for a little more money you can upgrade what you have... for my case, my budget was just to install the HU and leave everything stock until I save more...

In future I really do want to change all speakers out and get component focal or bostons if those are still around...

in mean time, i'll just have to use what I can afford...

[pfarmer]

It would seem like it to me. Sounds like pfarmer has some electrical engineering experience. Bose is pretty well known for using components rated at 2 ohms in order to get more power out of a low-power system, so I don't think there are any crossovers or differences in how it's wired compared to the non-Bose system.

Impedance is analogous to resistance, it's the same thing.

It really isn't exactly the same although the values are both expressed in ohms.

Impedence of a circuit will change with frequency whereas resistance can be thought of as not changing with frequency. Basically to impedence match or impedence bridge an output of one device (amp for example) to another (speakers for example) the circuit need to take in consideration of the frequencies and the range of variation.

You are pretty close in your thoughts of my experience. Basically I started out in the early sixties working on audio and video equipment and ended my career working in power generation stations. In the case of audio and video equipment you do impedence bridging for the purposes of maximization of the voltage from the source to the load. In the case of power transmission you want to maximize the transfer of power from the source to the load.

However there are similarities to the two. Keep in mind that a typical speaker can be seen as having inductance due to the nature of the windings (coil) and have capacitance due to the relationship of the windings to each other. The same can be said with the speaker cable, however at audio frequencies this is probably very minimal. Now add these same elements from both the amp and the speakers and whatever else is in the circuit (crossovers, etc.) and you need to consider impedence bridging.

In power generation you need to consider types of loads. For example in the morning you have a bunch of electric furnaces coming on line in peoples homes. Now these same people turn on their televisions. Now they all leave and go to work at the local factories with various types of loads inductive or reactive. The generating equipment, transformers, etc. all need to take this into account. Now all are setup with voltage change schedules to handle this daily variation and oil prices go through the roof, and everyone switches from electric heat to natural gas. Your local mills shut down and your inductive loads disappear. Think of the load being capacitive, what does a capacitive circuit see when initially energize, current flow or voltage? Now if inductive, current flow or voltage? Which one leads in each case. We refer to this relationship as VARS IN or VARS out and the typical short term fix is voltage adjustments to change what the load looks like to the generation equipment, often aiming for what is refered to as 'unity'. Big problem for sure, however this usually takes place over a fairly long time period allowing for infrastructure changes to the system.

Not so in high end audio equipment where these changes are basically instantaneous.

Another part of this often overlooked is reflection of the load on the source. A common speaker also does a fine job at being a microphone. That is its movement will generate a signal of its own that reflects back into the circuit driving it.

So to do this correctly you need to have a circuit you introduce that (for simplification) varies in resistance as the source and load varies in resistance and constantly satisfies the needs of both. So back to the first part of this post where the statement was made:

'Impedance is analogous to resistance, it's the same thing. '

You can think of them as being one in the same, however in reality you need to think of them as this since they really are not the same in this situation:

Impedence of a circuit will change with frequency whereas resistance can be thought of as not changing with frequency.

Perry


Modified by pfarmer at 11:43 PM 1/17/2009

[pfarmer]

300 isnt much more but at same time i dont think it makes much difference... ive tried that in my altima back in the day.... i think to hear a significant change in sound quality, really shoudl just get an multichannel amp and get those component speakers! those have a HUGE difference...

When my friend put in those component infiniti's in his car and some of that dynamat you can hear a big difference, then when he upgraded them to component focals, it was a greater difference!

in mean time, i'll just have to use what I can afford...

I'll put it this way. For $300 you can have fairly good components in all 4 doors of a sedan and I believe you will hear the difference.

That said the last line of your post is certainly a valid point, that is what you can afford.

My thinking is I would probably have done the reverse, that is I would have spent less on the head unit and spent more on the rest such as speaker replacement. The reason is that assuming you are going to power everything off the head unit, you would be hard pressed to hear the difference between lets say a mid level Pioneer head units built in amp and that of a higher level Pioneer head unit. The main differences for the most part will be in what you don't hear, like features for iPods, Bluetooth, etc. Look at the specs of various units (distortion levels, etc.) and I think you will see what I mean.

Now in a particular situation it may well come down to time. For example next month the money comes available for the speakers, you don't have to scrap anything you did. However lets say it will take a year or two to get there. For me I would prefer to go with fewer features and have a greater listening experience over a time period such as that.

Perry