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[Dave DND]

I would suggest save the turd polishing, and find a solution! I mean who's the expert here?

Fair comment -

Option 1 that I am working on:  I have modified a Porsche / Bose adaptor that should allow ANY aftermarket head unit to run in place of the OEM one, but will full integrate with teh BOSE amp / speaker setup - needs a bit ow tweaking.

But you may be more interested in Option 2, for those of you who like OEM stuff, as not only do I have a CD70 up and running, but it is also starting to show some of the data on the screen from the check control - Admitedly its a bit "heath robinson" at the moment with a couple of extra circuit boards hung off the rear, but I have about 70% of the fuel computer functions and bulb warnings operating through it at the moment !!

But, you are missing the point - This thread is not about replacing or upgrading BOSE, its about a replacement speaker solution for those of you refusing to move on.

[Dave DND]

The only reason the ice industry dont like the system is they cant sell us anything to add to it or replace it with.

No, its because the car is old and dead - there is no money left in it

When most of the cars are worth significantly less than a grand, what is the point in spending tens of thousands in research and development when most of you are not going to spend more than the car is worth on the finished product.

I think my route would be aftermarket speakers and an amp that takes speaker level inputs. No visible difference from standard and a much greater choice of components.

And I have been banging on about that for ages - keep the visual appearance and retain full functionality, but upgrade all teh bits that cannot be seen by the visable eye - You all do it to the engines, tweaking and tuning and adding bits, yet refuse to apply the same logic to the audio

I just don`t understand why not?

And no, it does not have to be chavved up with gay blue LEDS, nor anything you will find in 99% of car audio shops, I agree with you there, most of it nowadays is utter tat - but thats not what I am trying to offer you all is it?

[Dave DND]

No matter how hard you polish a turd - its still a turd !!

please tell Simon Cowell that !!!!!!

Amen to that one !!! 

[Dave DND]

Is there no way of fooling the system with a parallel resistance across the speaker?

Did have a play with this, but the volume levels were all out of balance with the cabin and the sub became really "boomy" by comparison - Also tried two pairs of lower wattage 4 Ohm speakers in parallel to try to get the volume right that way, but the sound was truly awfull.

No, the BOSE system was designed to run just about as well as it could at the time, and very difficult to upgrade a single component of it without really upsetting the balance - hence the emphasis on the need to replace and not retain bits

Its also going to be very intersting to see what some of the Ideas from MaxV6 throw up, as he is certainly coming at this problem from a very different direction, but cannot fault some of his theories and ideas !!!

[Dave DND]

Interesting the ice industry cant sell us a set of speakers to improve the thing.

Actually they do, and always have - but you also need a new amp to run them.

[feeutfo]

Interesting the ice industry cant sell us a set of speakers to improve the thing.

Actually they do, and always have - but you also need a new amp to run them.

I fully expect you to be told to take a chill pill Dave. But I won't hold me breath.

[MaxV6]

since someone mentioned it, i'll take a moment to deal with it.....   in public..

the resistor across speaker to fool the amp thing.

the problem with this is three fold really..

1) a Speaker is not a straight resistor,  it's a reactive load,   the impedance it presents to the amp varies with frequency (and power )

so while it may nominally be say 2 Ohms at 1KHz, it maybe 4 Ohms at 15Khz, and 2.5 Ohms at 65 Hz   , or some other such nonsense...  (figures here are entirely made up to illustrate a point, not pulled from actual data on the system)

the trouble here is that with only a nominal 2 Ohms as the starting point, , ANY measurable variance is quite large with respect to the nominal average...

2) A resistor, is NOT a reactive load,  it's broadly flat line , (*at audio frequencies anyhow)   and does not present any back thrust to the amplifier....     whereas the moving coil of the driver does....   as it moves around in the magnetic field due to the drive signal,  it in turn generates current by the same process...         

thus , slapping a straight resistor across a higher impedance  speaker in parallel,  to "fool" the amp, changes how the speaker reacts to input....   and the impedance presented, and frequency response sensitivity changes....   

so, the only way to do it, is to build a dummy reactive load,  with the appropriate impedance characteristics to compensate correctly across the required audio bandwidth,  , and present the the amplifier with the drive load it is expecting....   at all frequencies..

of course doing so, wastes a significant portion of the power the amplifier is putting in to the system,  and you end up with a lower maximum volume.... 

the complication here , is that since the Bose system, as i understand it, is response compensated for volume... this may result in a very odd spectral balance 

there are still ways to cheat a bit further, but it potentially gets increasingly complex , and still may not be a perfect result... 

3) 2 Ohm drivers use a thicker voice coil winding wire ,  and have a different motor mass ,  making the transient response different from an otherwise identical driver (say a 4 Ohm or 8 Ohm coil, using the same cone and spider assembly.. ) and their efficiency is also different...  (dB/W) ,  this is not really something that can be compensated for in a parallel reactive load.... 


with all that in mind, it is potentially cheaper and quicker to find a source of new replacement 2 Ohm drivers for those users who want to keep their Bose rigs,  but have failing , biodegrading drivers...

that said, i still fancy having  a play with the idea....   seeing if i can get the relevant performance parameter specs for the original drivers, and a range of alternatives, and if it's possible to calculate a compensatory reactive load that would use commonly available cheapish components....       the  moment you start needing custom wound components,  it becomes financially silly.....       but IF that's all possible, seeing how well it performs.... 

the suspicion Dave and i share, is that it's not feasible in a practical reality,  and certainly not for the average DIY miggy owner.

my interest is largely theoretical,  rather than any urgent need....   my car is non bose, so i can change drivers any time i like.....   

[MaxV6]

as to how much current a speaker generates by moving, did you know a common trick in recording is to tape a Yamaha NS10 bass driver to the front of a kick drum, and then hook it up to a mic pre-amp and use it as microphone....   

it's small in comparison to the amplifier output, but it IS there....

indeed yamaha even started manufacturing  a kick drum mic based on that .....    it's  called the sub-kick.

(i'll get me anorak and go sit quietly in the corner for a bit .....  ) 

[adey2]

i was looking on fleabay re speakers and there a company in america selling the 2ohm ones, but for some unknown reason he has in his listing will post worldwide but not to the eu countries wtf is that about

[feeutfo]

Guessing it's not straightforward to replace the cone? No? Thought not. 

[MaxV6]

well,  actually , now you mention it, i guess wembley speaker services might be able to find a cone kit for them.....   unlikely , but possible....

in other drivers,  (bearing in mind i am so NOT a car audio specialist.... so have only "normal-ish, if somewhat picky" experience with the specific environment, )  often it's the edge materials that are the problem,  foams and rubbers that decay and rot....  and are A) near impossible to completely remove, making a good seam join around the edge and former....   and B) going to fail again  anyway....

paper cones in the dry, are MUCH longer lived than the rubber and foam surrounds...  ....  I've got paper coned guitar speakers from the 1960's that still work just fine....  but have been refitted with new edgings....  it depends on the glue and the edge material really in those cases....  coz there are other similar aged drivers that are likely to disintegrate if used in anger....

PA & Instrument amplifier drivers and high end Studio monitor speakers are my field....  not car speakers..

[MaxV6]

i was looking on fleabay re speakers and there a company in america selling the 2ohm ones, but for some unknown reason he has in his listing will post worldwide but not to the eu countries wtf is that about

probably something daft like lead solder used on coil feed wire....

[feeutfo]

Re foam kits seem available on eBay, so guess it's doable. Depends where they fail i supose?

A new market reparing Bose speakers for Dave perhaps?

[Dave DND]

Re foam kits seem available on eBay, so guess it's doable. Depends where they fail i supose?

A new market reparing Bose speakers for Dave perhaps?

The foam does seem to dissapear in large chunks rather than simply deteriorate, and yes, this is certainly a weakness of the speaker. The other problem is that due to the high moisture content of the environment that the speakers are in, ie: the door, they are constantly subject to dripping water from the window seals, condensation from low overnight temperatures and fairly fast changes of temperatures when the haeter is put on. The result is that the compressed paper cone has largely lost its structure over the years. Visable deterioation is very easy to identify with a quick inspection.

A good experiment for you over the winter - put a piece of cardboard outside overnight, let it get damp and cold, but not wet, then dry it out with a hairdryer and leave it to bake in the sun during the day - repeat this process for a week or so, and at the end of it, have a look at the state of the cardboard - the surface will be knackered (so will the inside, but you can`t see that bit) - well, thats broadly whats happening to the speakers.

It is also important to bear in mind how car audio has evolved over the years, and I`m not talking about the technology, more the requirements. In the early days, the manufacturers felt it a very good idea to install speakers in all four corners as it distracted from the noise and rattles of the car, and industry statistics also proved that more vehicle faults were reported when the stereo had failed, which they obviously did in the early days. We`ve all been there, you are either singing along or thinking "I`m sure that thud wasn`t there before" when the volume is turned down. As "radio noise" was far more important than "radio sound" at the time, remember it was still very much a novelty, the speaker components were built on an absolute shoestring and had little or no quality whatsoever - the budget for a Cavalier speaker was around 10 cents, and that wouldn`t buy you any quality at all. And this also explains why the makers like BOSE achieved such phenominal success with the systems they designed - rather than noise makers, they designed something that sounded very good - and had speaker manufacturing been more advanced, then yes, plastic may well have been used instead of paper, but it wasn`t. Nowadays, the emphasis on car audio has once again shifted from how it sounds, to "how many gadgets can you cram in" and all of us who have been driving for a few years will all see this as a backwards step - me included. Car audio was better ten years ago than it is now, and that really hurts me to say that.

Many companies do actually offer a recone and repair service for many of the older subwoofers, but it is not a cheap or easy job. But typical prices for this are around £80+ per speaker, hardly worth it for such a cheap speaker, which is why a modern replacement is often considered.

Speakers are certainly out there, an amplifier solution is certainly out there, they always have been, but the underlying argument is not about BOSE, its about putting your hands in your pockets and justifying what is being offered as a very good alternative many years later.

And there lies the real problem - the subject of "Vehicle running costs".

But I will now eagerly await an answer to this question from the BOSE purists out there who refuse to accept that anything could ever sound better.

And my question is, If the BOSE system was so good all those years ago, then why has the company themselves always been at the cutting edge of audio technology and have indeed remained a strong contender in the 21st century by designing new and innovative, and often stunning sounding systems incorporating modern speaker technolgy instead of remaining with the paper cone technology and limited sound quality of a very early system design, or did they not see themselves that there was significant room for improvement 20 years later?

[Dave DND]

chrisgixer, just so I know I am going in the right direction, I need you to answer a question for me.

Are you hoping that I can find a solution to:

A) Upgrade the sound quality of the BOSE audio system, and accept that this will mean the replacement of various BOSE components within - (excluding the head unit)

or

B) Find a workable solution for those of you who have broken elements of the BOSE system and need to replace the now discontinued faulty BOSE components within so that the BOSE system can be retained as much as possible - (excluding the head unit)