Swapping out just the amp in a Bose car will DEGRADE sound quality because you are eliminating the built in equalization curves that have been "optimized" for the vehicle + the cheap Bose speakers installed. You're better off replacing both amp and speakers. Alternatively, replacing JUST the tweeters is likely to work, only because minimal EQ is used, and the factory system does not have a sophisticated crossover slope. You have to level-match them, though.

You cannot produce quality bass using the factory enclosure, without violating the laws of physics. By quality bass, I mean meaningful volume in the last audible octave (20-40Hz) at low distortion. I am not aware of any bass driver, at any cost, that can produce high quality bass from an enclosure of the factory dimensions. The closest you'll get will maybe be dual 6.5" with heavy EQ in a rigid replacement enclosure.

 

Agreed. The replacement amp story is the classic installer recommendation.

Happy to demo to anyone in the tri state area that a straight speaker swap with the stock amp yields excellent results and I'm not the only one that has done it.

Also agree about deep bass from the stock enclosure. However, swapping the sub drivers is also a huge improvement. Right, nowhere near 20hz,but a huge improvement nonetheless.

 

Yeah, I tend to agree with you on the amp thing. With home audio while an amp does make a difference, the biggest difference is the speakers themselves.

I'm not sure I'm ready to tackle doing the speaker replacement myself. I'll see how much a good audio shop charges for it.

I also don't need/want 20Hz bass. My dual 18" home theater set up provides plenty of that What I want is tight punchy mid- to low base, not subsonic stuff. I'm pretty sure I could achieve that by changing out the drivers in the existing sub box. And if necessary I'd change out the amp as well, but it looks like that would be pricey to do as I'd likely need a line convertor with DSP to do that and the good ones are at least $700.

 

You got it. The speaker install is pretty ambitious, but hopefully I've provided enough tips to make it a bit easier. Some have had a shop do the work at pretty nominal cost.

 

I am not so sure about this. I have three experiences that point to swapping the amp will have a bigger improvement on sound than just swapping speakers. But before I go on, I will fully admit that "better" is subjective when it comes to sound. For some, a bigger bass is more important that say accurate female voice and much of taste depends on taste in music styles. So, I am fully OK with disagreement on this question of amp vs speakers. Also, the "biggest" impact in any multi-component system will come from improving its weakest link and to determine that, that you must experiment and I believe it is the electronics from my experience #2 below.

My three experiences:
1 - I replaced the complete stereo, amp, headunit, speakers in my 2000 S Boxster that had the upgraded factory system. I did this in steps. My first instinct was to replace just the speakers and keep the look stock. My installer recommended replacing the Becker head and amp first. I did this.... I kinda knew I was going to do the whole system in time... The difference in sound was very surprising to me.. gone was the tizzy harshness and vocals sounded more natural. I didn't have to turn up the volume as high to hear with the top down as did before. Higher definition, or higher fidelity, system (in general) allows the ear-brain system to not work as hard to interpret the data and therefore you don't have to play a system loud to hear clearly. Much less fatigue using a high fidelity system in a noisy environment. Then, a few months later, I replaced all of the speakers. There again was a big improvement but honestly, the biggest improvement by far was from replacing the electronics.

2 - A friend at a local Porsche meetup had a 997.2 where he replaced just the headunit/nav/communications/amp and installed all Alpine electronics. He left the Bose speakers alone. Wow.... it "clearly" sounded better than my 997.2 with all Bose electronics and now Focal speakers. It was just better. Here is my real proof in that the darn car/system was the exact same as mine so I had an apple-to-apples comparison. We both jumped from car to car and difference was obvious.

3 - Now this is very subjective..... when I replaced the speakers in my 997.2, I was very happy with the sound upgrade but I can still hear the deficiencies with the electronics. I have been a home audio nerd since my teens and am now in my 50s and I know what a bad transistor amp sounds like and to me, the Bose amp sounds like classic bad MOSFETs. I don't know if the amp uses MOSFETs but it certainly sounds like it to me. The accuracy of the Focal speakers exposed it for me. Again, I know this is really subjective, but when I realized (fantasized?) that the amp sounded like a classic, cheap MOSFET design, I realized that the biggest improvement ultimately would come from an amp swap. For those nerds my age, the Bose electronics sounds like those 70s era Japanese amps built during the THD reduction wars where they used massive feedback to drive the measurements down.

To summarize, this opinion is highly subjective and frankly, the only way to really know, is to compare different approaches in the same car and I had the opportunity to do just this in scenario 2 above (and 1 but that was a Becker system).

Anyway, it is OK to dissagree. If someone can figure out how to tap into the Bose headunit and grab the 5.1 pre-outs, I will snap in a new amp in a nanosecond and report back. Of course, after that, I will now be suspicious of what evil the Bose pre-amp would be doing but I would be stuck with it because I want the 5.1 DVD-A processing it offers.

"Swapping out just the amp in a Bose car will DEGRADE sound quality because you are eliminating the built in equalization curves that have been "optimized" for the vehicle"
My comment: Possibly... but it really depends on way too many factors. What counts is does the end simply sound better? When the equalization curves are built, assuming they put dummy heads with microphones in the ears, they not only equalized for the cabin environment but also the deficiencies in the total system of electronics and speakers. So you really don't know what is happening when you start swapping as some things are improved and some degraded... the proof is in the eating and my system now sounds better with the Focal speakers.

Just a note on my musical taste: I could care less about sub-woofers, bazookas, or any explosive device that sets of car alarms. I know people who rate audio systems by how many car alarms they set off..... oh well......vive la différence.

Peace
Bruce in Philly

 

Bruce, I can certainly appreciate your experience on this. As you say, there's certainly no way to know. Here's what I would say:

For your 1st observation, 15 yrs ago, factory stereos did not integrate cabin/speaker equalization curves. So replacing the electronics, of course, should give you better sound. Nowadays, for cars with the Bose equalization, you are removing this benefit when you swap out only the amp. As to the reason why installing new speakers didn't provide a big improvement, I would have to know more about the installation and the speakers you put in. It is very easy to "upgrade" speakers and make your sound worse. Things like improper level matching, poor choice of mounting location, crossover issues, gaps in mounting seals, etc. - you can easily make your factory system worse (or better in some areas and worse in others).

For the second, again, I don't know the details of your friend's installation vs. yours. If his Alpine setup included basic equalization, or often, a microphone-based auto-EQ (Alpine's Imprint system), then it's certainly possible his system could have sounded better than even a basic competition-level system. It's been done before. The JBL team inserted an $700 MS-8 mic-based EQ into a factory BMW sound system and took 1st place in a major sound quality competition. What concerns me is that in your comparison vehicle, Focal speakers were inserted into a system with Bose electronics - was a system integration device inserted to flatten the factory EQ before you did this? If not, of course, it's going to sound worse. It's like taking a good stereo system and having someone "mess with" the EQ curve. And I'm also curious how the Focal system was installed (particularly on how you integrated it with the factory sub).

For your 3rd example, nowadays, as you must know, it is ridiculously easy for even the crappiest electronics manufacturer to produce an amp with flat frequency response and inaudible levels of distortion. Yes, even Bose can do this. Gone are the days where the factory electronics are so bad that upgrading them makes a big difference. To give you a counter example, I initially kept the Bose amp, THEN added factory EQ flattening prior to feeding an aftermarket amp/speakers. I subsequently upgraded to a Pioneer deck, eliminated the need for factory EQ, and well...there was absolutely no difference between the 2 setups. And this is with Focal Utopia Be speakers and a Mcintosh amp.

People are free to do what they like. If they upgrade the amp alone (and remove the Bose EQ), then there WILL be a difference in sound. And if that "difference" is interpreted as an improvement, great. And if not, there's always the option of upgrading everything else.

 

That was my instinct...but... I think we have it a bit backwards... Keeping the Bose electronics and swapping speakers keeps the curves that are related to the cabin.... the cabin didn't change only the speakers. If all speaker designers build for a flat response within a frequency range, then swapping speakers should not hurt the desired effect of cabin shaping as the shape (equalization) is stored in the Bose electronics.

Replacing the electronics is when you loose the shaping for the cabin. Swapping electronics for higher-end stuff, as is the Alpine units, you usually have a ton of controls such as an equalizer, independent gain control by amplifier channel, and selectable crossover frequencies. While you can argue it would never be as good as dummy heads with microphones and say 1/3 band digital equalization, you can get a darn good match if you have good and experienced ears... I had it in my Boxster.

Interesting stuff.

By the way, I have used those microphone/Audyssey shapers for home theater and usually ditch their recommendations an just do it by ear. I have a few test CDs with tones and sweeps that I use and, I believe, get better results. The problem with these home units is they add time delay and reverb to give a "big sound" and that just annoys me. It always adds some odd phase shifty thing that really bothers me. Remember listening to those simulated stereo records like the early Beatles with headphones? Blech.

Peace
Bruce in Phillly

 

My feeling is there is always more than one way to skin a cat. I've spent my fair share of time playing with high end home theater and 2 channel audio. Yes, higher quality more revealing speakers will unmask crappy electronics or what they are. It will also reveal your sources poor quality as such if they are so.

I have no doubt Bose has a special equalization curve to work with their crappy 2 ohm amp and their WalMart quality speakers. It seems to me it may not make much of a difference whether you swap one out vs the other. Both are bad.

OTOH we have testimony from people here on this forum who've done the speaker swap and testify that they can hear a significant difference. I'm inclined to believe that a speaker swap will make the bigger difference.

That's going to be my phase 1 upgrade. If I'm not satisfied with that, I'll add the amp/DSP to the system.

 

Ok, I'll say it again, good move. No money back guarantee, but I'm sure you'll be happy . The Bose amp is pretty good. I've read and heard all this stuff about sound eq from the amp, but then I saw the low and high pass caps on the speakers themselves. I think the speakers have Neo magnets, that's why they are pretty light, but swapping them out with reasonably priced alternatives makes a night and day difference. Just be sure to replace everything or disconnect what you don't replace. And keep to the same maker and preferably the same line of speaker from that make throughout the car. You really want the voicing of all the speakers to be the same.

When Bruce referred to those other experiences, I noticed something else was consistent. Not only was the amp replaced, but also the head unit. The head unit will make a pretty good difference - much more so than an amp. All the stereo shops will want you to swap out the head unit and replace it with a $2000 Alpine with the $600 fiber optic interface to run with the Bose amp. Change the drivers for half that money, add a Dension if you need digital and you will retain the stock look, be able to switch everything out when you sell the car and have much better sound. I'm sure a new Alpine head unit will give better sound out of your crappy Bose speakers, but I think it is really not the best solution.

Good luck and let us know how it works out.

 

Conrad, aka ryem3, hope I got that right brother. Just want to thank you. Iv finally gotten myself to do this project and all I can say is I am pleased with what I did. At first I got the polarities mixed up and I said this sounds awful. Then a researched and found out my misstake. Reversed the speaker polarities and now it sounds so good. I couldn't imagine the big difference. I think I hit an accident by going with 3 inch speakers at the back as it just provides enough rear fill to be noticeable. I am totally impressed with this install. For the first time I can say I am happy with my sound system. Don't know how it will sound with focal rear fills but the speaker I used really seemed to complememnt the focal tweeters and mid range speakers. Going with focals for the rear full could have been an overkill. Seriously this is one mod that should be recognized.

 

Thanks man. Be sure to do my sub mod. It is really cheap, totally easy and hugely rewarding. Do those rear speakers - I got those coax speakers for $100 a pair. Oh and be sure to note my update on the rear panel install. When I did it in my second car, I didn't remove the rear panels to install them.

 

Brother, never really thought your upgrade will make listening to the sound system a pleasure but it is. Now.. Can't imagine it getting better still. I have done my rear speakers and seriously think it's also part of the listening experience. I however have not done the sub change. Don't have access yet to those sub exchange speaker, but as it is the bass seemed matched. I will go and get those sub speakers one day and I'm sure it will impress me again. I just have to back read were the specs are.

 

This is an epic thread......thanks to all involved.

Took me quite a while to find out where the details of the sub mod were (2/12/14 10:28 PM FWIW).

Maybe someone out of the kindness of their heart can compile the latest recommendations.

 

I'm still doing mods to this mod. Current try is to put in a 2.75" 4ohm full range speaker with 90 sensitivity. The speaker immediately has more mass in the speakers..it fits perfectly albeit tightly. But initial sound test, the center speaker still overpowers the rest of the system. The speaker cover is not yet installed. I will fix all things in place and give it another try. Will keep all inforemd

 

For info I followed this wire legend:
http://cai-store.com/pages/car-audio...ns-for-997-987
This has the legend for pre and post 2008 cars.
For everyone's reference