RX-8-Tobi
09-20-2003, 04:17 PM
Dear rotary and music friends.
I'm a German guy who was reading your postings very interested.
I only had an account to RX-7 Forum, so I decided to join the party. :-)
PLS TAKE YOUR TIME READING THE LONG FOLLOWING "NOVEL", IT'S WORTH THE TIME.
I did not hear a RX-8 sound system cos the RX-8 is not available here so far.
You guys are ordering the car like lunatics, so we have to wait. ;-)
I saw it first time on the IAA in Fankfurt last week. Great car.
Being rotary lunatic (owning FD), liking listening to good music and adicted to technical stuffs, this is the right forum for me I guess. ;-)
I will try to learn from you about the RX-8's factory systems. Together we can begin to improve the system if necessary.
I did not change the factory speaker setup in the RX-7 cos the German one is damn rare (around 100) and I want to leave it stock.
But I think the RX-8 will not be that kind of "collectible" and so hey, why don't do some custom stereo?!
I do work at a German car audio magazine as a sideline, so I think we will have some fun here. :-)
First of all, I think the Bose system could sound quite well and most of the "average" listeners seem to prove that.
The 9 inch doorsubs should produce enough bass for most of us. Well, I will have to hear myself.
The only bad think imo is that Bose again did not give us "real" tweeters. I would say the 2" speakers are good for frequencies upto 10kHz.
So I may miss the "magic" that higher frequencies add to the music.
Bose systems are not easy to modify/upgrade cos each component is setup with the others.
The speakers usually have low impedances to reach max output of the amps. And Bose uses (usually well done) equalization to eliminate the special car acoustics and to improve the standard quality speakers.
So any afermarket speaker will not fit the installation.
My personal opinion regarding Bose systems is: Leave it stock or throw anything out.
Well, adding subs with external amps might be a problem. How does Audiopilot react? Is the speaker were I get the high level signal time delayed or equalized?
Changing speakers is different as we do not know the impedance (it is not the same like dc resistance!). And remember the equalizing thing! Most important the spl of each speaker fits the others.
If you miss the magic I told above, I would recommend using a additional 1" tweeter left and right door.
Put it in the panel where the 2"s are living, I think it's big enough there. Just use a 3,3 yF cap to make him play over 10k (if 4 Ohms speaker).
That might work. Not sure about equalizing or Audiopilot. Just be sure that the spl level of the 1" tweeters fit the other speakers. You could use resistors to make it softer, but can't do anything to make it play louder. ;-)
Ah, not to forget, changing the simple 22yF cap will improve the 2"'s sound quality. Just use one with higher quality (foil cap), but these will get damn big.
So just wire a small high quality cap parallel to the big stock one, that works as well. Maybe 2,2 yF?
Step two would be to make your own custom stereo. Well, I think we can keep the headunit and the features like fantastic style integration, display and steering wheel switches.
Bose amps usually have high-power inputs to be able to use the same headunit like the non-Bose systems do. At least the 3rd gen. RX-7 did so.
We just need a high fidelity high/low converter. We did test one recently and it had impressive mesurements. -1 dB at 20 Hz and -2dB at 20 kHz. Wow, that should do fine for us.
It's about 150 USD, but most cheap adapters are just yuk.
Of course it is possible to replace the whole headunit thing, but lots of work and no display or remote control any more.
The frequency measurement was good work. But I have to say that frequency mesurements in car are damn tricky. You cannot just put a micro in the car.
We do use an average of 100 single mesurements (the PC does of course) to get a fitting frequency curve. Turning the mike around our head from one ear to the other.
And I have to say that the bass boost is badly needed in the car. That is because of the car acoustic, quite complicated. Maybe I will try to explain later, but I fear my English is not good enough.
Depending on the car size, we need a bass boost of about 10..14 dB starting slowly at about 250 Hz. Smaller cars need more boost, vans work fine with 10 dB.
And to compensate driving noise (hey, Audiopilot? ;->), we even need some more dBs.
And the highs should play a bit softer starting from about 8k downto -6dB at 20k.
Also the AUX-In was good job. I just don't like the thing with extra cassette unit.
If we knew the pinout and signals of the connectors, should be possible as well easier.
I don't think they used digital signals to sitch the decks, just different lines turned on/off.
We just need to know HOW...
So you see, lots of things to take care of, even many more than I did mention.
Some things that come to my mind and I want to know:
- were is the Audiopilot function integrated? The headunit? The overview says it's in the 5-ch-amp. How about the fronts then?
- impedances of speakers?
- time delay?
- speaker equalization? in amps? or headunit!?!
- frequency range of speakers and place of dividing networks? only the tweeter caps?
- what equalizer possiblities in headunit or just bass/treble?
- any low-level outs? I guess no.
- PLS post scans of the headunit connectors and what they are for!!! You should find in factory workshop manual from Mazda garage.
- Also PLS post the system specifications and the COMPLETE wiring overview.
- do the 9" have enclosures or use whole door space?
- does the headunit show CD-Text?
- ....
All of that will help us to find a way how to start serious high fidelity. ;-)
The following picture is my first contribution to this great audio forum.
It shows what components are used in the Bose system.
I think not all of you were sure what's behind the covers.
http://www.tobias-albert.de/rx_8_tobi_bose.jpg
So just slow down running a bit before we know exactly where to go. ;-)
rgds
Tobi :-)
I'm a German guy who was reading your postings very interested.
I only had an account to RX-7 Forum, so I decided to join the party. :-)
PLS TAKE YOUR TIME READING THE LONG FOLLOWING "NOVEL", IT'S WORTH THE TIME.
I did not hear a RX-8 sound system cos the RX-8 is not available here so far.
You guys are ordering the car like lunatics, so we have to wait. ;-)
I saw it first time on the IAA in Fankfurt last week. Great car.
Being rotary lunatic (owning FD), liking listening to good music and adicted to technical stuffs, this is the right forum for me I guess. ;-)
I will try to learn from you about the RX-8's factory systems. Together we can begin to improve the system if necessary.
I did not change the factory speaker setup in the RX-7 cos the German one is damn rare (around 100) and I want to leave it stock.
But I think the RX-8 will not be that kind of "collectible" and so hey, why don't do some custom stereo?!
I do work at a German car audio magazine as a sideline, so I think we will have some fun here. :-)
First of all, I think the Bose system could sound quite well and most of the "average" listeners seem to prove that.
The 9 inch doorsubs should produce enough bass for most of us. Well, I will have to hear myself.
The only bad think imo is that Bose again did not give us "real" tweeters. I would say the 2" speakers are good for frequencies upto 10kHz.
So I may miss the "magic" that higher frequencies add to the music.
Bose systems are not easy to modify/upgrade cos each component is setup with the others.
The speakers usually have low impedances to reach max output of the amps. And Bose uses (usually well done) equalization to eliminate the special car acoustics and to improve the standard quality speakers.
So any afermarket speaker will not fit the installation.
My personal opinion regarding Bose systems is: Leave it stock or throw anything out.
Well, adding subs with external amps might be a problem. How does Audiopilot react? Is the speaker were I get the high level signal time delayed or equalized?
Changing speakers is different as we do not know the impedance (it is not the same like dc resistance!). And remember the equalizing thing! Most important the spl of each speaker fits the others.
If you miss the magic I told above, I would recommend using a additional 1" tweeter left and right door.
Put it in the panel where the 2"s are living, I think it's big enough there. Just use a 3,3 yF cap to make him play over 10k (if 4 Ohms speaker).
That might work. Not sure about equalizing or Audiopilot. Just be sure that the spl level of the 1" tweeters fit the other speakers. You could use resistors to make it softer, but can't do anything to make it play louder. ;-)
Ah, not to forget, changing the simple 22yF cap will improve the 2"'s sound quality. Just use one with higher quality (foil cap), but these will get damn big.
So just wire a small high quality cap parallel to the big stock one, that works as well. Maybe 2,2 yF?
Step two would be to make your own custom stereo. Well, I think we can keep the headunit and the features like fantastic style integration, display and steering wheel switches.
Bose amps usually have high-power inputs to be able to use the same headunit like the non-Bose systems do. At least the 3rd gen. RX-7 did so.
We just need a high fidelity high/low converter. We did test one recently and it had impressive mesurements. -1 dB at 20 Hz and -2dB at 20 kHz. Wow, that should do fine for us.
It's about 150 USD, but most cheap adapters are just yuk.
Of course it is possible to replace the whole headunit thing, but lots of work and no display or remote control any more.
The frequency measurement was good work. But I have to say that frequency mesurements in car are damn tricky. You cannot just put a micro in the car.
We do use an average of 100 single mesurements (the PC does of course) to get a fitting frequency curve. Turning the mike around our head from one ear to the other.
And I have to say that the bass boost is badly needed in the car. That is because of the car acoustic, quite complicated. Maybe I will try to explain later, but I fear my English is not good enough.
Depending on the car size, we need a bass boost of about 10..14 dB starting slowly at about 250 Hz. Smaller cars need more boost, vans work fine with 10 dB.
And to compensate driving noise (hey, Audiopilot? ;->), we even need some more dBs.
And the highs should play a bit softer starting from about 8k downto -6dB at 20k.
Also the AUX-In was good job. I just don't like the thing with extra cassette unit.
If we knew the pinout and signals of the connectors, should be possible as well easier.
I don't think they used digital signals to sitch the decks, just different lines turned on/off.
We just need to know HOW...
So you see, lots of things to take care of, even many more than I did mention.
Some things that come to my mind and I want to know:
- were is the Audiopilot function integrated? The headunit? The overview says it's in the 5-ch-amp. How about the fronts then?
- impedances of speakers?
- time delay?
- speaker equalization? in amps? or headunit!?!
- frequency range of speakers and place of dividing networks? only the tweeter caps?
- what equalizer possiblities in headunit or just bass/treble?
- any low-level outs? I guess no.
- PLS post scans of the headunit connectors and what they are for!!! You should find in factory workshop manual from Mazda garage.
- Also PLS post the system specifications and the COMPLETE wiring overview.
- do the 9" have enclosures or use whole door space?
- does the headunit show CD-Text?
- ....
All of that will help us to find a way how to start serious high fidelity. ;-)
The following picture is my first contribution to this great audio forum.
It shows what components are used in the Bose system.
I think not all of you were sure what's behind the covers.
http://www.tobias-albert.de/rx_8_tobi_bose.jpg
So just slow down running a bit before we know exactly where to go. ;-)
rgds
Tobi :-)