Bob The Eskimo

I would like to see this test done with the fade set to full front and full rear. If you set the fade to full rear, the 9" speakers in the front doors still put out bass. Has anyone else noticed this as well?

I have not checked it with the front fade yet, but this makes me think that maybe we should tap the door speakers for our sub signals. Same function, just a lot more cable to run.

I have not looked at the bose amp in the rear decks outputs. Does it send signals to the front speakers? If so, we can just tap them.

I own a cd with a sine sweep from 20Khz to 20hz. I will find out if the rear deck is actually full range or not.


Thoughts please.

bob

mohrt

Isn't this what the PAC OEM-1 was built to solve?

http://www.pac-audio.com/products/oem1.htm

Bob The Eskimo

Isn't this what the PAC OEM-1 was built to solve?

I don't know if what they call 'fixed level' means pre amp signal, or ballanced differential signal, so I can not answer this accurately. If it will not accept ballanced differential, then no. If so, then yes it is the answer.

mohrt

I cannot answer accurately either, although the post from the previous page notes that the PAC tech took a look at the RX8 wiring pics and claims that it should work, just hook the wires up directly to the unit.

elite

im totally confused...

Ballanced Dif. signal, whats this all about.....

Id like to test the rear fader and see if we still get LOWs comin outta the doors.

bottom like is
we need to tap somwhere thats FULL RANGE or low if we want to add a sub.

Im a firm believer to let the amp do the crossing over and let the line being tapped give a full range signal. its just the sure way to get around all this "what if" stuff.

Just really seems like taping at the HU is the better option, true signal output there.....who know, i think i am more confused them when i started

mdw33333

The amplified signal from the Bose amp to the rear speakers IS full range. There really is no more "what if" stuff. A 2 or 4 channel line level converter tied into the amplified outputs of the Bose amp is the safest, cleanest route to upgrading your sound system, period. This thread contains a detailed explaination as to why this is true.

Bob The Eskimo

The amplified signal from the Bose amp to the rear speakers IS full range. There really is no more "what if" stuff. A 2 or 4 channel line level converter tied into the amplified outputs of the Bose amp is the safest, cleanest route to upgrading your sound system, period. This thread contains a detailed explaination as to why this is true.

Well said, but has anyone tried to get a 20hz signal from the amp?

I will give it a go right now.

hang on.

Bob The Eskimo

at volume 20 and at 10hz the speakers (6x9" and 9") are clicking like mad. this is to be expected. at 20 cycles, the speakers are fluttering like crazy and trying to make the sound, but unfortunately, 6x9"s arent going to cut it.

at 27hz the 6x9"s are making audible note with little distortion, but it is horribly faint due to the free air mounting. (I have also replaced my 6x9"s with Fozgates.) the front 9" speakers chime in at about 28hz. a very faint noise, but damn if the door panel doesnt feel like it will fly off.

I would have to bet that it is full range. 100%.

the sine sweep from 20khz to 20hz even sounded like my old system used to. I know that was full range.

but, the front speakers did seem to be thicker and louder coming through. Plus, they have the bass signal from the front and the rear fade. Maybe we should tap into these and it would add the front bass signal to the rear signal for a more rounded sound. any thoughts?

Bob The Eskimo

I tried to tap into the front speakers for signal but could not run the wire into the rubber hose to connect the door to the car. what a stupid thing to prevent me from taping the source.

but anyway. . .

--------------------------------------------------------------------------------

When tapping the rear speakers, use these colors:
Left Rear + is Purple
Left Rear - is Pink
Right Rear + is Black/Blue
Right Rear - is White/blue

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These are the wire colors at the speakers themselves. I used this guide, but when I connected it to the amplifier one side was out of phase. I don't know if these pinouts were backwards or if something inside the N-774v I received was backwards. At any rate, I clipped off the connectors to the Pink and Purple wires on the left side and swapped them (Pink + and Purple -) and everything got much louder.

So, all in all, I would reccommend this approach and I would recommend the N-774v.

eXe
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I had the exact same problem. my 6x9"s that i connected are in phase, but the navone adapter seems to be reversing one of the phases. I swapped the phase on my amp and the sound almost doubled in volume. I have one sub set up as a test runing left and right signals into each of a dual voice coil speaker. With it wired properly, the speaker was not even moving. with one reversed phase, the voulme was deafening.

Man I love this. What I have now is only 1/2 of the install and it is already deafening.

Does anyone else thing the navone is reversing one of the phases?

elite

Just got off the phone with dave himself....cool guy.

He said, this IT IS possible, but if its the case the wires are simply mislabeled. Accidential mislabeling, it happens!!

He said he just got/built a new batch of those adapters, and he was checking it out now he said, he was testing so ill try to get an answer if moving forward you should double check or the new versions are all good. Obviously if you notice this out of phase (which I would imagine is obvious right away) simply switch one side.....

I should get my navone adapter today....but I ordered the 2 channel version, model N-7V. Im sure ill know right away.....ill report on that model for you all when I get it in.

very interesting.....

Bob The Eskimo

He is a really cool guy. he knows his stuff too.

It was kinda neat to hear the phase cancelation in a Dual Voice Coil sub. You could play with the left and right gains and make some freaky bass. Mre reverb of the sound rather than the sound.

Come to think of it, I think I just found a way to isolate the reverb generation used in specific music. Useful for the studio.

Otherwise, I am completely satisfied with the Navone. I am not even sure it is the navone yet. I will check my wires tonight to make sure I did not do anything stupid.

elite

i just got my converter...looks nice, hope its all wired correctly....

there is a 5th wire, black....assuming ground....did you all use that wire, or no? I think typically you dont...but im not sure....let me know..

thanks....

DreamWarrior

Wow...what a PITA. So folks, here's what I'm thinking:

1) Tapping after the Bose amp is, IMO, a really bad idea. Why? As stated, you are stuck with whatever equalization and crossover slopes bose chose to use on the speakers for which you are attempting to tap. This, IMO, is not acceptable. This is especially unacceptable if you plan on performing your own equalization and setting your own crossover slopes, which any "real" system should be doing anyway. Even for simple add-on sub systems, it is always nice to have full control over your cross-over settings an an uneditted (unequalized by the Bose amp) signal.

2) The AudioPilot crap is all within the Bose amp, so tapping into any of those speaker outputs will entirely screw up the AudioPilot. Of course, you'd be turning this off in said cases, and if you tapped in before the amp you'll be losing it anyway.

3) The speaker outputs are just that...they are usually high voltage and quicker to distort. Not to mention that they are typically biased around 1 ohm (for speakers), where-as any decent preamp output will be substantially less than that. In and of itself, this lends to potentially poor quality when converted, depending on the quality of the converter and its bias. Then throw in all the other equalization and crossover effects that the Bose amp introduces and you have an ugly situation.

So...with all this in mind is seems that the true ideal solution is to find a suitable tap into the head unit PRE-Bose. If this requires a special unit to convert the, potentially, balanced signal into a standard 4-5 volt low impedance output then so be it.

What I'm wondering is, if I was to be able to develop such a thing, who on here would be interested. Keep in mind that I'm in no means saying that I'll be able to, given my lack of spare time, but if I was...would I have supporters?

mdw33333

The reasons for tapping after the bose factory amp are valid and have been discussed in detail in this thread. Please "read" the thread to gain a better understanding as to why this is the best solution for this system. BTW, the rear speaker leads after the Bose amp are full range.

DreamWarrior

I read the thread, thanks. I've still never heard a LOC sound nearly as good as a nice clean pre-amp level signal. Obviously the Bose amp is designed to drive speakers, it is biased at around a 1ohm impedance level, and it is amplified at a much higher level than pre-amp outputs. Therefore, a LOC (or a LOC inside the amp) must take an amplified signal biased around 1ohm, convert it to a typical low level (1-5volt MAX RMS) line level signal and then re-bias it to its nominial impedance for line level inputs (which is generally MUCH lower than 1 ohm). Of course, then this signal has to be amplified again.

The is rediculous and lossy and regardless of whether the signal is full range or not, you're still at the mercy of the LOC quality AND the quality of the Bose amplifier (which IMO is not all that great). You're also bound to any equalization (AudioPilot for one) that the Bose amp performs. At least tapping in before the only eqalization you're bound to is the tone controls in the head unit (which you can at least zero). I'd be willing to put money that the Bose amp has some built-in equalization settings that they determined would make the sound "good" in the RX-8.

Anyway, I read the thread...so don't acuse me of not doing so. I know why you all believe this is the best way...I'm just trying to tell you that its not optimal and that a correctly converted pre-Bose HU signal would sound way better than the best LOC.

Bob The Eskimo

I think we are starting off on the wrong foot here. Lets bring things down so we can come to the best solution for the problem at hand.

Optimal situation is to tear the whole damn thing out of the 8 and start from scratch. This is not an option that many of us want to do.

So lets start at the begining here. The signal going into the bose amp is differential, at 1 volt. At one volt there would be a large amount of noise in the system. Yes, you can tap this (positive side only) but you would need to amp this signal several times and turn the gain up on your amp almost the whole way (running hot). you also amplify noise.

With the signal coming from the head as is, it is 180 degrees out of phase from istself. The bose amp reverses one of the phases (-), and then combines them. You experience phase cancelation that effectivley removes the noise. The signal after the amp will have less noise than the input signal if the differential is removed and then amplified. Fact.

The bose amp is full range. We have tested it with sine sweeps and dB meeters. All is good here.

The amp only puts out about 3.5 ohms at peak. No bose amp will put out 1 amp in a car that I have seen. A LOC will take this 3.5 ohm or any ohm input for that matter and bring it to a few milliohms output for the RCA input on amps. This is different than volts. Some inputs on amps can handle up to 15v. David navone has some of them himself, I have one that will take up to 20v, and another that recommends 9. They are all over the board. The fact remains that the higher the v input, the less noise the system will pick up in transmission from the head to the amp.\

Some of us have proven that the AudioPilot (crap as it may be ) works pre and post amp. It must come from somehting in the head, not the amp.

If you know of a differential signal converter that works for about 34$, we are all ears. otherwise, test and determine.

DreamWarrior

Bob:

The voltage between the head and the amp is signficant, as you said yourself, to reduce transmission noise. The balanced signal does this as well. However, if you only transmit < 1 foot between the head and a balanced signal converter, the 1 volt balanced is substantial enough. Of course, Bose obviously felt that 1 volt balanced was substantial to transmit the entire length of the car to their amp...so hey I guess 1 volt can't be that bad at rejecting noise.

Second, the Bose amp still probably has equalization.

Third, I find it hard to believe that the AudioPilot comes from the head...I don't see Bose giving their secrets away to Pioneer (who manufacture's the MP3 unit) to incorporate the Audio Pilot there, do you?

mlino01

If the the head unit on the bose and non bose are the same does that mean that the non bose equiped system is sending a diferential signal to my non bose speakers? I thought these lines were standard power feeds.

Bob The Eskimo

1. This voltage is weak. The only reason that noise removed from this system is that it is BALANCED DIFFERENTIAL. This is different than a standard preamp signal. Tap this signal and you will send a live signal directly to ground. It is weak, so it may take some time to fry the head, but it will most likely happen.

Sending a Balanced differential signal to a standard +- system is bad (similar to connecting the negative terminal on your battery to the positive terminal).

2. May be so. But none of us have been able to detect it. Post your evidence if there is any to suggest otherwise.

3. Confidentiality agreements, Patents; many things help companies work together and share secrets. We do it every day at my business. Plus, bose would not have to share anything with Pioneer who built the mp3 player. This piece just sends standard RCA signal to the head, and the head is the unit that contains the Audiopilot.

We are all willing to believe you are right, just prove your case.

Mlino01, the head must in some way be capable of putting out a speaker line output as well. A speaker can not take a balanced differential signal. The only thing you would hear would be noise.

mdw33333

Well said Bob.

skatingaway

Having read this thread I can see that the recommendation is to use the signals post amplication. However, has anyone actually succeeded in connecting to the differential outputs to provide an input to an amp, and is there a suitable connector to allow this?

My preference would be to take the signal going to the front amplifier and use this to drive an amp for a set of Focal 6.5" component front speakers and a subwoofer in the back. Anyone tired this sort of install? I would expect this to give a more neutral balanced tone - the BOSE 9" woofers in the front sound dreadful to my ears and create loads of rattle in the door panels when turned up.

LYFK

I have used the Navone converter that we talked about here for about 3 months now. It is perfect. I have not had any issues. This is the best method in my opinion, but it's the only one that I have personally tried.

Bob The Eskimo

That last post was me.

Sorry,

My computer for some reason logged me in as some other person.

Just bob here still rambling away.

skatingaway

Thanks Bob, but I believe you're connecting to the speaker outputs after the BOSE amp. What I really wanted to know was if anyone was successful in connecting to the differential outputs from the head unit.

My main concern is that, although the BOSE amp is full range, I'm not convinced that it's frequency response is flat. I've tried adjusting the bass and treble on the head unit but can't get what I would consider a decent sound output. The treble sounds harsh and the bass muddy and overblown. Is this really just down to the speakers?

newtlicious

I have read this thread thoroughly and I see both sides of the fence. I have read elsewhere that to overcome this phase differential in the pre-amp signal, you can just tap the positive leads of the pre-amp signal and ground the negatives of your RCA plugs. With this in mind I have the following questions. Could you.....
1.) send the negative RCA grounds to the same location as the amp ground?
2.) use an inline voltage amplifier to boost the preamp signal to > 1v before the sub amp.
3.) how does it hurt your HU to tap this pre-amp signal? I don't understand why it would puke just because the signal is going to a sub amp instead of the bose amp.
4.) my amp has a gain that ranges from 200mv to 5v. Would running it at 1v to match the input voltage really run it that hot? Seems on the low end of the gain to me.

skatingaway, many folks on this forum have successfully tapped the differential pre-amp signal with only 1 reported incident of a cooked HU. I consulted with rotarygod on this one and he said that he used to tap into factory HU's exactly this way (pre-amp signal, no convertor) without any problems. It seems that almost everyone involved has said that it sounded much better without the convertor.