I guess what I don't understand is that a lot of what you're saying doesn't really apply to car audio:

The audio source will be digital, so pointing out that "vinyl is best" doesn't really help. A good DAC isn't a bad idea.

The Bose headunit has been shown to output a very flat signal to the amp (not so much after), so you can't ask much more of the source. You'll hear more difference from speakers than wires or a new HU.

An external amp is preferred quality-wise over an internal amp. Some of the best head units don't even have an internal amp (p99rs).

Wiring doesn't matter that much so long as it's properly sized an insulated. Check this out : Speakers; When is good enough, enough - Page 3 coat hangers sound just as good as monster cable.

An elitest attitude towards music just rubs me the wrong way. For most ears there is a better, cheaper way to enjoy it. Especially in a sub optimal environment such as a car.

I don't have a lot of time to devote to this tonight, but I will chime in with a few thoughts. Keep in mind I have been working with audio since I was a mere kiddo.

1. Speakers offer the absolute most bang for the buck upgrade, and anything you do upstream cannot be heard through lousy speakers. So start with the speakers.

2. Sound reproduction requires clean power, and at least 50% more of it than you might think. Modern technology has made this relatively cheap. Do it if it is feasible.

3. Speakers require good, inert enclosures to sound their best. This is where Damplifier and Dynamat come in. They go a long way to converting lousy enclosures into less lousy enclosures. And, the difference is very audible--at least while you are stuck at the stop light.

4. The source can be important, but many are good enough already unless you want more features. Most source units are decent--especially the preamp outs. The Bose HU sends a flat signal to the amp, as I have demonstrated. There appears to be some jitter, but that could easily be in the laptop sound card I used to take the measurements or anywhere else in the testing system. I am willing to bet the Bose HU is fine in terms of audio. Further, in a car audio environment, while motion is occurring, most listeners cannot discern better DA converters. Don't believe me? Several recent studies have proven that self-proclaimed audiophiles and professional recording studio engineers cannot discern higher bit rates or premium converters with better accuracy than 51%. In any case, the HU is the most expensive component to replace, and the law of diminishing returns (in terms of audio) is in full effect here.

5. Cables only need to be good enough in car stereo environments. Any mid grade cables will suffice as long as they are capable of carrying the required current or have sufficient shielding according to their purpose. Home stereo and recording studio environments are different, as the noise floor and other aspects of the listening environment are completely different than what you find in a car--especially a small sports car. This car is noisy when it is moving, the Fletcher-Munson curve is always in play, and the terminal acoustics are absolutely terrible. High end cables will gain you almost nothing here. It is better to focus on finding good ground points, etc.

I will vigorously disagree with you about the order of operations in upgrading a car stereo (see my previous posts), but I would rather focus on the idea that I think you have missed my point. I am not pondering adding power. I am thinking of replacing the Bose amp, which I have shown to contain strange filter networks, which are assumed to enhance the sound of the lousy Bose speakers, with a flat EQ amp of similar specs to better compliment my newly installed non-crazy speakers, which expect to be fed a flat signal. The amp to which I linked can use all the factory wiring and is smaller and lighter. The drawbacks are in the specs (THD and SNR), but those specs can't be any worse than factory. I probably won't do it, since the system already sounds a thousand times better than before, and I only drive this car once or twice a week plus track days, but it certainly is tempting to keep pushing the envelope of what can be done while keeping a factory appearance.

Doesn't that just contradict what you said a few posts back?

The speakers play THE most important role in ANY audio system. Going from one head unit to another or swapping amps (Bose excluded) or w/e will have less of an impact on the sound as changing speakers. These days it's easy to produce a flat source because all the DACs and audio stages are IC chips and everyone is stuck using the same crap.

It's not like the old days where every stage of your source was designed from scratch using individual components.

stvnscott - I think it's lucky for us that the Bose HU signal is as flat as it is. We used to say the non-bose guys had it made but if there's any EQ'ing going on in their HU, they're f'd. At least we have a good starting point. I've already eliminated the Bose amp. Don't fret it. You'll be happy when you do. Don't forget to plug the big hole in the deck when you remove the Bose amp. :) Once removed, take a look inside. $50 says it's class-d. ;)

Hmm, shouldn't be. Speakers = better upgrade, so I agree with you.

I'd been drinking when I'd posted at least one of those though.

I was wondering if you had thought about some of the shallow mount subs to put in the doors? The 10"Alpine SWR-T10 has a cutout of 9-1/8" and top mount depth of 3-1/4"? There are few 8" as well (the Pioneer is a free air design). I am not sure of the cutout size in the door or the mounting depths, but to free up trunk space I was thinking I could go this route, just add a sub amp and remove the Bose "subs" completely? Would be easy to make a mounting bracket to fit the 8's if the 10's wouldn't fit. Just a thought I had. Replacing the tweeters, rear deck and adding the subs may push all the mids to the rear though depending on what the Bose "subs" are outputting. After looking back through, it appears as if the 9" Bose are handling the mids and lows . . . My idea would not work if this is the case . . . The Pioneer TS-SW841D has a freq response up to 1500Hz, however I am sure the rolloff on that will still leave a big midrange hole, I just saw them on crutchfield so I am looking for any spec sheets for them . . . The Pioneer website doesnt show the FA charasteristics and shows -5dB at 500Hz in the best case scenerio, but stops there. Wonder if that would work?

The problem I'm having is the lack of midbass/midrange in the front. The 9" Bose woofer/sub does a poor job reproducing mids. Bose also put a fairly large (22uf) cap on the door tweeter attempting to push that little 1.5" paper tweeter into the midrange. That combined with the center channel is where all the mids are coming from but a center channel can damage stereo imaging. To me it sounded very harsh and my first stereo mod was replacing the door tweeter caps with a 10uf.

My next step was to replace the Bose tweeter completely with a 3/4" dome. Now I needed to get the door woofer to play higher into the mids. The 8" Pyle midbass I used did a fairly good job at it, while still maintaining quite a bit of midbass punch, but it fell a little short of the upper midrange, so, I'll be replacing the tweeter again with a larger 1.25" dome tweeter. I feel then I will have a nice starting point.

Pyle PBW8S Pyle PBW8S 8" Midbass 292-2532

280wrms
1.5" voice coil
3ohm
95-5000hz
Fs 108hz
Sensitivity 96db
Depth 2.87"

https://www.rx8club.com/attachment.p...1&d=1382420723

That is the rub I guess, get some mids and midbass or just bass . . . I am just hoping to not use my trunk up with a sub (I have the spare tire kit so my trunk is already smaller). Maybe I will spring for the Focal Integration ISS 200 (if there is enough depth that is), runs the full range 40-20k with an 8 and tweet component system . . . I dont need to go bumping down the street, but I like my music full and a good bit of lows.

Even though the Pyles are considered a midbass driver they do play quite low. If I turn off my high-pass and unhook the sub it still sounds better then the Bose system and I could live with it but I do like the deep "cinema bass" that my 8" subs provide.

I'm sure the Focals will sound great up front and don't underestimate what a good set of 6x9s can do in a rear deck. I have a feeling Bose high-passed the factory rears because the Pioneers I stuck back there give the illusion of a subwoofer being in the trunk. If you do your rears, cover/seal the deck with Dynamat and put an extra layer around the edge of the speaker opening. Don't get a 6x9 with tweeters that stick up more then ~1/2" or they hit the covers. Also, the rear tweeters are seriously lacking output. New speakers bring new life back there.

Watch your depth up front. The corner of the window is right behind the magnet. Next time I shop I'm going neodymium.

How much clearance do you have with your Pyle's (approx is fine) if you recall?

Maybe 1/2"

this helps a lot
 

Although I don't own a rx8 yet, i seriously plan on getting one. this post help me understand more about the car in terms of sound quality. i currently own a 1997 jeep wrangler that has an amazing sound system. It is crisp and loud, although the wind noise while driving over 25 mph drowns out almost everything. Your post helps me understand more about the bose system, and prevents me from doing my own trial and error. Thank you.

If you do, set aside a couple grand for a new engine.

So when u spend another 6 grand for the touring model the "300 watt" BOSE in it is still crap? I have the sport and the stereo is so bad it defies description.

Bose in general is overpriced garbage if you are a true audiophile. Not saying I am, but bose is to speakers what monster is to cables .... marketing genius

Bose basically gives good midrange in everything they put out. Since most of their systems are single driver based, they usually have to roll off the lows and highs when the volume is turned up so as to not distort or "muddy" the mids and highs. It appears in this system, they have a midbass driver in the door with a tweeter. Tweets can not really handle the lower part of the midrange and a midbass driver can not handle the upper end. What they have to do is roll off the bass at louder volumes from the midbass driver in order to keep the mids clear. The saying I think goes "No high, no lows, must be Bose". So, if you don't like detailed highs or low end, it will be fine. As an example, go into a good audio store and listen to "She Talks to Angels" from the Black Crowes on a Bose system, then listen to the same song on a good set of speakers, there is a high cymbal in that song (that can be a little overpowering) which you will barely hear on the Bose and will be loud and clear on a better system. If you can find a place that sells a good set of KEFs, it will sound like someone was standing in front of the Bose blocking all the details when they switch to the KEFs it is like the person moved out of the way, the difference will be pretty shocking. Same deal in a vehicle, although with all the engine and road noise they can hide it better. This is the reason people put sound deadening materials in their cars, to make it quieter and easier to hear the nice subtleties in the music.

Yes. If I did not have a lot of prior history with Bose, I would have been SHOCKED at how much engineering went into making such a lousy sounding stereo. They would have done much better to make a high power head unit and pair it with some Pioneer or similar speakers. It would have sounded much better, and think of the weight savings considering the amp and all the wire they used.

For an OEM system it's not horrible (compared to most typical OEM stereo/speakers) but sold as a "premium upgrade", I agree. It falls well short of it's price tag. It seems like Bose threw 3 dozen darts at the dart board and none of them hit a bulls-eye. I do like the amount of bass they got out of the doors though but that's it.

Bose has always sucked in the home stereo market but I am somewhat impressed how good they get very inexpensive drivers, in an equally cheap box, to sound. Nothing justifies their price tag though.

Things will be changing soon. I ordered an Alpine MRV-F300 amp to replace the Bose amp and a pair of Alpine R Series component speakers for the front doors. PVC mounting brackets for the speakers and amp are also on the way. It may take me a few weeks to get to it, but all traces of Bose except for the head unit will soon be gone.

I need to decide what I am going to do about the balanced inputs to the Bose amp. Like kickerfox, I am measuring a constant 4.5VDC to ground from both conductors of each input to the Bose amp. I will probably just build a simple 4 channel direct box, but I will look at what I can buy first.

I used 2 capacitors (per channel) to remove the DC offset.

Scott - How's the audio system going?

After spending some more time listening to the Pyle 8" midbass speakers, I decided they're a little boxy sounding. Fs is probably too high. Too bad because they really do put out a lot of sound (drums are incredible) but there's one really peaky frequency ruining it. As loud as they are, I had trouble getting a tweeter to blend with it (tried 4 different sets) and I'm not going to bi-amp the system. Then it dawned on me. Why not an 8" 2-way ceiling speaker?

So I bought these.

Not in the car yet but they sound really good hooked to my home receiver. My 12w/ch tube amp was uncomfortably loud playing through them.

I haven't done anything with it yet. I have all the parts here, but my free time with the car has been consumed by a suspension replacement nightmare. That is all sorted out now, but with track season starting up in earnest, I doubt I will get back around to the stereo for several months.

Ceiling speaker eh? That's thinking outside the box. I wonder how an open air speaker will sound mounted in a door...

Sounds good. Have a look. There's pics here.

Don't you have an ill-advised engine swap to be working on?

;)

Lies! I'm bone stock. :D:

I'm saving up for all the plate and tubing for fabrication. The weather put me on hold as well.

Curious if anyone has the Bose Amp Connector pin outs. I have a Lc2i and sub and amp going in this week hopefully I want to jack the audio signal before its amplified by the factory unit to add my sub in. Anyone?

Super swamped with work so maybe someone else can post the pinouts but make sure you decouple both phases of the signal if you plan on just connecting it to an amp without a balanced input or you can and most likely will fry the headunit.

I posted the pinouts on page 1. Kickerfox is correct. Make sure your LCi2 can handle balanced inputs or decouple the signal lines to remove the DC offset with some capacitors.

The lc2i is suppose to handle up 400w input signal from the speakers/or amp and covert it to full or low range quality preamp signals. Only way to find out is try so ill def let you know.

I'm looking to upgrade my bose system as well. I want to get a bit more bass in my system but subs take up too much space and i need my trunk space. I was thinking about replacing the door speakers to get some more bass, what would you guys recommend? I am also getting a new kenwood head unit if that changes anything

First of all I'd like to thank the OP and others for the information provided in this thread. I got exactly what I wanted from this. I bought a 10' shallow sub and the direct fit enclosure for it. Takes up almost no room in my trunk in the top left corner and sounds amazing going off the rear speaker wires and remote wires specified on pg 1 with a LC2i and just a cheap 500w bridgeable BOSS amp. The preamp I'm getting off the LC2i is just amazing quality to me. I still have my fully powered bose system with a deeper bass to it (hits pretty damn good too). I am thinking about swapping the tweeters out next for some alpines that work in that low range someone was discussing earlier (the OP I believe) to see if that will turn things just right! I'm plenty satisfied though and glad I did my homework. Thank you all!

Careful with your tweeter selection. The Bose tweeters are crossed over very low and play well into the midrange. The hole up front is large enough as it is. Aftermarket tweets aren't crossed over low enough.


Adding a tweeter in front of the Bose tweeter, and crossing it over fairly high (1uf) would help a bit.


The whole Bose system is a disaster. I spent weeks trying to get it to sound right and finally gave up and put in a 4-ch amp and new speakers. I'm very happy with it now.

It is hard to make a direct recommendation, since there are so many products available. You might start at Crutchfield, where they recommend speakers that fit specific cars according to their hands-on research. Consider which units are in your budget, then look at their specs. You want speakers that go down to 50Hz or lower in their frequency response.

After a very quick glance, these new Kicker units intrigued me in terms of low end extension, although I wish they had soft dome tweeters.

Rear 6x9s

Front 6x8s

Anyway, don't take my word for it. Speaker selection is very personal. Spend a lot of time on research. It is always worth it in the end.

Also, per my earlier posts, consider treating the doors with Damplifier Pro or Dynamat Extreme. Those products really do improve the bass response of car speakers.

Pics or it didn't happen!

I like mine OK with the Alpine tweeter replacement. It is advertised to go down to 1000Hz, which is low enough, and it blends decently with the Bose woofer. You might consider replacing one and fading left to right to see which you prefer.

Kickerfox's idea is also sound. Find one of the tiny super tweeters that you like and add it to the sail panel to play along with the Bose tweeter. You would cross it over to handle the ultra high frequencies the Bose tweeters can't. This would essentially be creating a 3 way system. Of course, you need to be able to construct a custom crossover to get the impedance, crossover points, and loudness right for the drivers.

Find some Subaru pillar tweeters. They will fit in front of the Bose tweeter and are suited to the task. Cheap on ebay.

Focal Integration ISS 200, it is an 8" and Tweeter component set, however you will need to not use the Bose Amp, then you can replace the rears with Focal Integration ISC 690. Get a 4 channel amp, of if you want a sub a 5 channel amp and drop a 10"/12" in the rear and your system will be stellar . . . of course dynamat helps all this out even more.

I know that dynamat makes the speakers sound better but does it dampen vibrations to the point that I will be able to notice while driving?

It will help dampen vibrations and quiet the road noise "effectively" making any stereo "louder" and "cleaner". I used the quotes because it does nothing for the sound of the stereo, but you won't have all the road noise interference to contend with while listening to your system, hence you will hear more of the music and it will seem louder.

Why did you choose the alpine SPS-110TW over the alpine SPR-10TW? Was it just a matter of price or is their something else?

IIRC, the tweeter unit itself is basically the same (except for some sort of EQ Ring thingy). The main difference is in the crossover, where the R series has a steeper slope (24dB) and is adjustable for level. I wanted the more gradual slope (12dB), as I felt it would blend better with the Bose woofer. Also, I thought the crossover would be cleaner and easier to mount in the sail panel instead of behind the door panel and was unsure if the R series unit would fit up there. Then there is the fact that I fell into a set of the S series tweeter for nearly nothing...

[I am relying on memory for all the "facts" stated above and could be wrong about any of it.]

I still have not gotten around to installing the Alpine component set I bought for the front and the Alpine 4 channel amp I bought to drive it all.

Now that track season is over for me until it cools down here, I have some time on my hands. Perhaps I'll get around to it now. But it's kinda hot outside and...

http://www2.crutchfield.com.edgesuit...0MRVF300-F.jpg

http://a248.e.akamai.net/pix.crutchf...C-o_other.jpeg

http://car-speaker-adapters.com/imag...K021/image.png

I think that's the same amp I recommended to a forum member (who I've been trying to assist on his install). He's quite happy with it. Hopefully it's not the class-d version. Did you catch the Crutchfield sale on it?

Scott, what solution did you choose for decoupling the balanced signal? Are you going to try the capacitor solution or did you find a store-bought solution?

It is the Class D version (MRV-F300). Not my favorite, but I doubt I will be able to tell much difference in this car when it is moving down the road. It is cheap, small, and LIGHT and good enough for this car. I bought it using Amazon Prime for about half what Crutchfield charges.

Alpine amps have decoupled inputs, so I should not need to do anything. A quick test with the multimeter seems to confirm this. Also, my subwoofer amp is an Alpine, and it has been working fine with the Bose HU for about a year now.

My Alpine v12 series didn't. Not only did it sound like crap, it would pop when input was connected and pop again when the signal is removed. That's actually how I discovered that there was DC present. The pop indicates there wasn't any DC offset removal on the input of the amp. If there was, the signal with the DC offset may pop when first connected but once the coupling capacitor charged it won't pop again when removed.


I'd still put the 8 capacitors in there. I used 10uf 16v non-polar axial caps and shrink wrapped them in series with every lead. 10uf is probably overkill, considering the input impedance of an amp, but I had them on hand.

Scott, you still watching this thread?

Had an update/opinion/question about the balanced lines from the head unit. What I was doing was adding caps on each of the balanced "hots" (to remove the DC) and connecting balanced (-) to RCA ground and balanced (+) to RCA tip. This worked well but I had this buzz at low levels in 1 second intervals when listening to a CD. I assume I'm hearing a digital clock pulse perhaps on the buffer. The balanced ground (shield) was left disconnected.

What I decided to try was connecting only the balanced (+) to the RCA tip and the balanced shield/ground to RCA ground. This got rid of the noise but what I didn't expect was the increase in stereo imaging. I verified the phase is correct and mono instruments are centered and full sounding so it's not "widened" due to the R/L signals being out of phase. It's strictly a gain in stereo imaging.

Any idea why this is? We know EQ'ing was done in the Bose amplifier but is their a chance the Bose HU still uses a DSP that's making phase corrections?

BTW - Bought a Memphis 16-MC4.75. Decent amp for the $50 I paid for it. :)

Over here in the UK all S2s are R3s and come with the BOSE stereo as standard. My situation is pretty complicated and I'm over my head even before I think about stereos. I've an R3, an S1 with a single turbo RX7 FD engine that I'm having to completely redo and a winter car (Honda Accord with all the Old Man comforts including a BOSE stereo). The S1 has the built-in sat nav for which I've got a Nexus 7 tablet and a double-din conversion kit but is very noisy. As a legacy from a previous car I've got an Alpine 4-channel 450w peak amp, Focal 3 component 165 speakers with front door panels and self-made mounting boxes, Focal 2 component 165 speakers with 6x9 mount, a Pioneer 500w mono amp with Focal 8" sub in a self-made enclosure replacing the ski hatch. I also have a Focal 2 x 180w RMS per channel amp and an Alpine 12" sub speaker. Alas, I've just lost my garage so any work depends on good weather, something in short supply over the next few months.

I'm thinking of putting the legacy system into my turbo and the Focal amp in my Accord, leaving me with a blank sheet for the R3. I'm short of time and don't want to spend £s only to have to sell her in the spring should the turbo work as hoped. I'm therefore looking at keeping the BOSE and changing the front speakers for now (Dynomat, tweeters, mid/bass). Quality sound deadening and the SPS-110TW tweeters are available over here so they look a good choice, but none of the mids/bass mentioned here are available in the UK.

Can anyone recommend any Japanese or European speakers (eg Alpine, Pioneer, Focal) for the mid/bass or give me specs that I can look for in units available in the UK?

You'll have difficulty getting anything to sound right if you keep the Bose amp. It has an internal DSP and EQ. That was Bose's way to adjust for a poor audio environment, budget components, and limited power. Many OEM systems have this. If you start adding quality components, they'll never sound right.

If I had it to do all over again, I would replace the front tweeters, Dynamat the doors, add a sub, and do nothing else.

If you decide to do more than that, you really need to replace the whole system beyond the head unit. As KickerFox said, the Bose amp really screws with the signal and yields very unpredictable results through aftermarket speakers (see the plots I posted on page 2 of this thread). Some music sounds fine through my system, and some music has me pushing the fader nearly all the way to the front to escape the weirdness of the rears. I have a new amp and front component set (with brackets) ready to install to fix these problems, but I am trying to decide if I want to keep the car or buy a Miata and install a turbo, so I haven't done anything more with the car's stereo. As it sits now, if I still had the rear Bose setup, I would put it back in and call it good.

Funny, I sold my Turbo Miata to buy an 8 and do an engine swap. The Miata was impractical for long trips. That was a '94 though. I haven't been in a newer one.

Hey Stvnscott - This