fatalus Posted July 1, 2008 Share Posted July 1, 2008 I would like to share my experience with upgrading my Bose system keeping the Bose headunit though. First of all I decided to upgrade the front speakers. I bought JL audio VR 650 components which fit fine in the stock tweeter location and with help of spacers in the stock door pods. Fairly neat install but the result was not so good as far as sound quality is concerned. Soundwise there was an improvement in quality, though tweeters sounded little harsh and mids muffled, but it was more than obvious that the Bose amp lacked even the slightest power to drive these speakers, which even made them sound less loud than the trashy Bose speakers. So I bought a JL audio G2250 amp to drive the front speakers. The installation was performed by a professional but I dont think he would make it without my instructions and the service manual! I put the amp in the passenger glove box and routed RCAs direct from the Bose headunit. The problem was with the speaker wires. it was impossible to locate them in the wire harnesses in the car, so the only option was to connect the pre-amp wires that leave the headunit with the speaker outputs of the JL amplifier. Then we had to go to the rear hatch and ,after taking out the whole trunk to locate the bose amp, bridge the pre-amp wires that come to the bose amp with the speaker cables that leave the bose amp! Everything else went as planned and the job was done rather quickly. As for the sound result...one word....AMAZING improvement compared to both the stock system and the speaker-only upgrade!! Amazing clarity, no harshness at all from the tweeters and fantastic detail! The only problem that i noticed is that the Bose subwoofer now almost works less than 50% of its previous power. I attribute this to the loss of pre-amped signal from the front speakers which does not reach the bose amp now, and to the fact that the rear speaker signal which is the only that reaches the bose amp now, is faded by -3,-4 in favor of the front. Anyway the end result even with the sub working low is zillion times better than before even bass-wise!!! I wonder if it would help if I connected and "copied" the pre-amp rear channel signal to the front pre-amp inputs of the bose amp as well. Any ideas on these or will I have to proceed and buy a sub amp and even a new sub in the near future? Quote Link to comment Share on other sites More sharing options...
Rob_Quads Posted July 1, 2008 Share Posted July 1, 2008 I think you have some of your inputs and outputs mixed up in the wording making it hard to work it all out... connect the pre-amp wires that leave the headunit with the speaker outputs of the JL amplifier. This means your connecting two OUTPUTs together? You sure you didn't mean the speaker inputs of the JL amp? Are you then trying to get the signal to the speakers by bridging the amp? Why didn't you just do... Bose Head unit...................................Bose Amp................................................Speakers Bose Head unit......CUT......JL Speaker Level input/JL Speaker Output.......CUT.........Speakers Quote Link to comment Share on other sites More sharing options...
fatalus Posted July 1, 2008 Author Share Posted July 1, 2008 Actually I meant it like that... The cables that used to transfer the pre-amp signal from headunit to the Bose amp were cut and they were connected to the speaker output of the JL amp , thus making them transfer speaker signal instead! It was the only way to avoid putting new speakers cables all over. Quote Link to comment Share on other sites More sharing options...
garry Posted July 2, 2008 Share Posted July 2, 2008 fatalus - in my opinion here you will always be fighting a losing battle using the bose amp and sub. The bose sub is of extremely poor quality, it'll be low powered compared to your front end and you have no ability to adjust the x-over point meaning the sub will be playing too much in the way of high frequencies which will be generally ruining your sound. If I were in your shoes I would invest a little more money on a decent sub + box + amp and I can assure you the improvement will be the same again. Now you have a power line run into the car to run your amp for your front-end, much of the hard work towards instaling a sub amp + boxed sub has been done! Also, I would recommend looking at a couple of products - both of which are intended to take speaker outputs from oem headunits and remove equalisation, boost signal and split into proper pre-out signals, as used by amplifiers. alpine pxe-h650 http://www.alpine-electronics.co.uk/ind ... d=pxe-h650 jbl cleansweep http://mobile.jlaudio.com/products_clea ... page_id=94 both do of course come at a price... but if you consider it being money you would have otherwise spent on a decent headunit then it's maybe not such bad value considering it lets you keep the oem look and will be easily transferrable to your next car. Quote Link to comment Share on other sites More sharing options...
fatalus Posted July 2, 2008 Author Share Posted July 2, 2008 I agree with you garry. A monoblock amp and a new sub + box preferably in the stock location is next in my plans. I can also add that now that the sub is almost non-existent in the sound picture, even basswise the system is awesomely better. The front speakers that run full range now more than make up for the low sub volume. I would just like to experiment by trying to raise the bose sub volume, see if it can merge with the rest of the system before I upgrade it. And you are also right, the installation of a new sub+amp will be easy considering the JL amp has pre-amp outputs which can be directly connected to my next sub amp. So no fuss with cables.. I could also say now with 100% certainty that the stock amplifier is completely rubbish. It is extremely powerless and the crossovering that it does is S-H-I-T! So for everyone that considers upgrading, this is the first thing that must be bypassed!! Quote Link to comment Share on other sites More sharing options...
Madmarky Posted July 2, 2008 Share Posted July 2, 2008 The Problem with the bose amp and speaker is they run at ohmage to after market HU's and amps. You say you used factory wires to wire up the front speakers, imo this is a bit of a waste on spending a load of money on decent front speakers. The quality would be so much better running new speaker cables, it takes some time to get them through the ISO connector in the door but it is possible. At the end of the day if you are happy with it then thats the main thing, any installation pics ? Quote Link to comment Share on other sites More sharing options...
fatalus Posted July 2, 2008 Author Share Posted July 2, 2008 Sure I could do better with new speaker cables but IMHO it is not worth the extra hassle and money considering that the result using stock wires is awesome. I could easily say it is on par with a good home system and I cannot imagine it being sooo much better with new wires. About pics I would love to have some but fortunately the whole system is completely stealth. Only the amp in the glove compartment can be visible and I will be back with photos ASAP. Quote Link to comment Share on other sites More sharing options...
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