Is the DSP stereo's bass weaker than standard 10-speaker?

[CFoote]

Originally Posted by iPhoneEngineer

OK, good to know! Now, is it possible to have the nav screen but no Carver/DSP?

Yep....NAV and DSP are two seperate items. I have a X5 I ordered new in 2001, and back then the "DSP" system only gave you DSP settings, the speakers were exactly the same as the base stereo. I saved the $1500 and just got the NAV. Not that BMWs NAV is anything to write home about as you know But it does what its supposed to; give directions...

Chris

[RichardTS]

Originally Posted by dekaliber

I have a navi on the M and I don't think it's that bad. I have all EQ and DSP settings off. IMO, the less electronics between the signal and the speaker, the better.

I don't remember it being all that different from my 3.0si, which did not have Navi, but did have premium sound.

I don't know. It's a sports car with a sweet engine and very little concern for dampening outside noise. (In fact, don't the 3.0si coupes have a sound generator to funnel in engine noises?)

Right on. Turn all echo snd room settings down to nothing. Set the equalizer dead in the middle on all frequencies. In the tone controls set bass and treble to the mid-points. Your system is now 'flat' and now you can find out where you want it.

Choose an original CD (NOT some MP3 job you did on your computer) that is a known good recording. Note that rock is very rarely recorded well and you can usually fond some good jazz recordings. When you start to dial something in, dial it in in small amounts and listen to it over time. You will eventually find where it works for you.

[MrTomas]

iPhoneEngineer, your problem with minimal output from the Carver woofers sounds exactly like mine. Have you made any progress on this, or learned any more?

[iPhoneEngineer]

Originally Posted by MrTomas

Have you made any progress on this, or learned any more?

Not yet, but the next step is near. I was finally able to find out from the dealer which day of July that the factory representative (usually called the "Factory Guy") will be on-site. It's only one day a month, and they supposedly don't know what day until the start of the month. I've been asked to bring the car in at 8AM on July 28th, and may not even be able to talk to him personally. BMW Mountain View is a large dealership, but I have been consistently disappointed by their service on multiple occasions, and will start going to another dealership for service if this doesn't turn out well.

Anyway, I found out that "there's an app for that," and downloaded some stereo test and SPL meter apps. There's a huge drop in output below 40Hz, but I haven't had the chance to try it on my friend's base roadster yet.

I haven't yet decided how best to indicate my research to the factory rep. Probably write up a note to leave with the car, at least, but I'm also thinking of taking some videos of the tests in each car and leaving them on an iPad.

[MrTomas]

What apps are you using for your stereo tests?

After I wrote the my previous question, I dug a little deeper into my own car. I popped the passenger side woofer grill and watched the cone move using an LED flashlight. The flashlight made it pretty clear how far the cone was moving. I got it to move 1 to 1 1/2 cm with some moderately high volume levels. I used my Jurassic Park CD which has some nice isolated low frequencies on track 1.

So, I guess in my case its a matter of properly tuning the DSP and tone setting to my liking.

By the way, I can't seem to get decent bass out of my iPod rips. I've been using the 192Kbps import setting, and the low end really drops off. It just doesn't compare to the original CD sound quality.

[Blind32]

I'm also intrested in the app. Maybe we could do a case study. All of us use the app with the same mp3, same settings and see what the results are.

[vicj]

Originally Posted by iPhoneEngineer

Not yet, but the next step is near. I was finally able to find out from the dealer which day of July that the factory representative (usually called the "Factory Guy") will be on-site. It's only one day a month, and they supposedly don't know what day until the start of the month. I've been asked to bring the car in at 8AM on July 28th, and may not even be able to talk to him personally. BMW Mountain View is a large dealership, but I have been consistently disappointed by their service on multiple occasions, and will start going to another dealership for service if this doesn't turn out well.

Anyway, I found out that "there's an app for that," and downloaded some stereo test and SPL meter apps. There's a huge drop in output below 40Hz, but I haven't had the chance to try it on my friend's base roadster yet.

I haven't yet decided how best to indicate my research to the factory rep. Probably write up a note to leave with the car, at least, but I'm also thinking of taking some videos of the tests in each car and leaving them on an iPad.

Of course there's a large "Drop off" under 40Hz. Your talking about 6.5 inch subwoofers in a TINY enclosure. It's not going to play like a JL 12-inch in a huge box. 40 Hz is pretty darn low. Plenty low for almost all music.

[CFoote]

Originally Posted by Blind32

I'm also intrested in the app. Maybe we could do a case study. All of us use the app with the same mp3, same settings and see what the results are.

That would not be a bad idea at all. I have a '05 with Carver, I'll be happy to help, but we have to have exact same volume settings and would probably be best to burn the MP3 to a CD so we have the same volume level for everyone...

[iPhoneEngineer]

Originally Posted by vicj

Of course there's a large "Drop off" under 40Hz. [...] 40 Hz is pretty darn low. Plenty low for almost all music.

You're certainly right...and my apologies for not including more in my last post. I actually ran out of time to thoroughly test this last weekend, but I'll describe what I tried and what's next.

So far I haven't spent any money on the App Store for this--under the logic that people will be much more willing to reproduce in their cars with free apps.

Frequency generators:
- "SubShredder" is a free app that will generate tones at six frequencies from 20-90Hz. This was the only tone generator I've had a chance to try out. There's a notable drop in output as measured by the SPL apps (below) at 20 and 30Hz, but as vic mentions, this is not unreasonable and shouldn't affect normal listening. More interestingly, there appears to be a ~10dB drop in my car between the 60Hz and 90Hz outputs, but I wasn't able to verify this trend with more frequencies because SubShredder's options are limited.
- "FreqGen" is another free frequency generator with many more options, but no automated sweeps. I will use this more tomorrow.
- There are many other frequency generators on the app store, including some cheap ones that do frequency sweeps, but I haven't bought any of them.

SPL meters:
- "SPL Meter" is a free, basic SPL meter. It seems to work well and is probably the best app for any comparisons.
- "RTA Lite" is a real-time [frequency] analyzer, which does a fast fourier transform and displays a breakdown of volume at different frequencies. This could also be a good comparison option, if people use the screenshot feature (simultaneously hit home and power buttons) to share their results at various frequencies.
- Again, there are more non-free SPLs and frequency analyzers.

Now, the big problem with these apps is that you need two to do the test. The frequency generators don't support playing their tones in the background while the SPL meters listen. So, at least until I dig into the audio APIs and write an app myself, you can only repeat the test with two iOS devices. Any combination of two iPhone, iPod touch, or iPad devices would work.

Is there anyone here interested in collaborating on a test who does have the devices necessary? If so, what generation iPhone do you have? It's likely that the iPhone 4 and iPhone 3Gs microphones have different sensitivities in practice, so we'll have to control for that. I have every generation and can repeat tests for people with a different device if desired.

I am going to run tests in my friend's base Z4 tomorrow, and will use a 3Gs as the recording device since it has the most units out there.

Also, how can we standardize volume levels? I don't remember, but is there a setting on the nav screen that shows an objective volume level indicator? In the meantime, I'll pick a frequency and bring the output up to a certain volume as recorded by the SPL apps.

Anecdotal reports indicate that there is a fairly widespread problem with the Carver subs, as some people are reporting admirable performance while others are sorely disappointed. It would be great to get together some hard evidence just in time for my next confrontation with BMW. In particular, people with awesomely-performing Carver systems, and two iOS devices, are the key comparison for my car--if there are any out there!

[dekaliber]

I wonder how much the SPL meters on the iPhone will tell you because I doubt the microphones are going to be as sensitive to deep bass as it is to higher frequencies. I would imagine that it's optimized to pick up the range of the human voice. I can't see how a full-range microphone would fit in an an iPhone chassis or even be reasonable from a cost perspective, considering a good one costs as much as or more than an iPhone.

Of course, correct me if I'm wrong since you have much more to do with the iPhone's design than I do.

You can buy an actual SPL from Radioshack for not much money (I can't remember if it was $20 or $50). It's what most semi-serious hi-fi audiophiles use for testing audio systems in their home. It will also solve your problem of needing two iDevices to do the test.

I confess that I don't know a whole lot about car audio specifically, so I don't know how manufacturers optimize subwoofer response. Position of the microphone will likely affect readings since there will be parts of the car where signal response is attenuated or amplified based on the acoustics of the cabin.

As far as standardizing volume, the control knob "clicks", so maybe you can turn the volume completely off (and then go a bit further just to make sure), and then standardize it to 20 clicks clockwise from zero or something like that.

[Blind32]

I can offer my help. Some of my family have iPhone 3GS's that I'm sure I could borrow for a quick test. Verison 4.0.1. I have a Z4M Coupe with nav. To be honest, I haven't looked into the stereo models of our cars and whatnot, I just hook up my aux in and it sounds good. Radio sounds like crap tho.

[wildag]

I have an iPhone 4 and a Z4M with Nav.

[CFoote]

I've got a 3GS with 4.0.1....'05 Z4 with Carver system.

I'm assuming we'll be testing top up

Chris

[CFoote]

Don't forget that the sound systems changed in '07. '03-'06 were supposedly the same while '07+'08 are the "THX" approved setup (and apparently the system got worse from what I've read)

Chrs

[thekurgan]

Originally Posted by CFoote

Don't forget that the sound systems changed in '07. '03-'06 were supposedly the same while '07+'08 are the "THX" approved setup (and apparently the system got worse from what I've read)

Chrs

The new THX is actually a nice system, for a stock radio, but there are a couple of things I've noticed:

1. DSP through the navi system harms sound quality
2. The subs need to break in a bit, then they sound very nice
3. JAZZ seems to be the best setting for many types of music

[chickdr]

Originally Posted by CFoote

Don't forget that the sound systems changed in '07. '03-'06 were supposedly the same while '07+'08 are the "THX" approved setup (and apparently the system got worse from what I've read)

Chrs

Are you sure about that? I understood the THX system was started in '06 with the refresh. It would make more sense the stereo was the same for 03/04/05 and then for 06/07/08. See post #4 here: http://www.bimmerfest.com/forums/sho...d.php?t=130986

Maybe this announcement meant it would be implemented for the 07 model year?

[iPhoneEngineer]

Originally Posted by dekaliber

I wonder how much the SPL meters on the iPhone will tell you because I doubt the microphones are going to be as sensitive to deep bass as it is to higher frequencies. I would imagine that it's optimized to pick up the range of the human voice. I can't see how a full-range microphone would fit in an an iPhone chassis or even be reasonable from a cost perspective, considering a good one costs as much as or more than an iPhone.

Of course, correct me if I'm wrong since you have much more to do with the iPhone's design than I do.

You're right to suspect that...I do too. I'm not personally involved with hardware design or familiar with the microphone specs offhand. However, as long as one doesn't rely too much on the "objective" decibel rating, and focuses on comparisons to other cars that seem to have good vs poor bass performance, there should still be a consistently detectable difference of significant magnitude.

Yes, the volume knob "clicks" would work, or the steering wheel controls...

Gotta run this morning, but I'll report some preliminary findings comparing against my friend's base stereo Z4 Roadster (yes, top up). If anyone knows for sure whether 2006 had the THX certification, that difference could be key in making sure appropriate comparisons are made...

[CFoote]

Originally Posted by chickdr

Are you sure about that? I understood the THX system was started in '06 with the refresh. It would make more sense the stereo was the same for 03/04/05 and then for 06/07/08. See post #4 here: http://www.bimmerfest.com/forums/sho...d.php?t=130986

Maybe this announcement meant it would be implemented for the 07 model year?

I'm pretty sure the THX system started in '07, if you look at the press release it was in '06, past the time the 2006 model year started. I don't think they implemented the THX system midway through the 2006 production process...

[edit: Just looked at '06 brochure, did not mention THX certification, but '07 brochure does]

Chris

[crfine88]

Originally Posted by danlauz

I had both car, one without NAVI and the actual one withNAVI and, definitively, the sound with NAVI is not good at all.

I have play with the setting of the base ans treble and EQU and, the net result is almost no BASS and most of the sound going to the front speaker. its much better but, never as good as my previous Z4MC without NAVY.

any other comments ?

+ 1^

I owned an '06 M roadster with business CD and the sound/ bass quality was awesome

I now own an '06 M coupe with Navigation and bas distortion is terrible.

Speaker config was the same in both cars

I have had it in two local BMW dealers. Both state that the stereo system is fine.

My dad bought an '06 M roadster without nav and his sound/ bas quality is awesome.

I am thinking about getting rid of the Navigation system.

[psygnosis]

I have a 2004 with Nav and DSP and the bass is great. More would be nice, but I never felt that it was lacking. Weird that there are so many inconsistencies with the radio in the Z4. I wonder if it's the radio, or more likely the amp.

[ZStig]

Originally Posted by crfine88

+ 1^

I owned an '06 M roadster with business CD and the sound/ bass quality was awesome

I now own an '06 M coupe with Navigation and bas distortion is terrible.

Speaker config was the same in both cars

I have had it in two local BMW dealers. Both state that the stereo system is fine.

My dad bought an '06 M roadster without nav and his sound/ bas quality is awesome.

I am thinking about getting rid of the Navigation system.

I think its the coupe/roadster acoustic difference. more panels rattle in the back in the coupe. I've confirmed this at a test drive back to back

[rich337]

I'm okay with the sound system, but the speaker rattles behind the seats drive me INSANE!!