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Coupe. Supposedly a very tight fit but I was assured by NW Musicar that Andy designed the GB40 FOR BMW's.

I did everything else first, keeping the factory mids for a minute while I waited for the GB40's to show up. Sounded OK. Added the GB40's. Absolutely amazing, midbass and voices just came alive!

On the install, I obviously ditched the ridiculously huge outer bezel, slotted the door card for the chrome inner bezel/grill's tabs, mounted the driver to the inner mount and installed that inside the door card with the inner bezel outside the door card poking through the whole assemble. I think some modification to the door card's mounting holes was necessary. In both cases I used a Milwaukee 12v vibrate saw with a small not terribly aggressive blade. You'll see when you get all the bits laid out.
 

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Coupe. Supposedly a very tight fit but I was assured by NW Musicar that Andy designed the GB40 FOR BMW's.

I did everything else first, keeping the factory mids for a minute while I waited for the GB40's to show up. Sounded OK. Added the GB40's, took the high pass all the way down to 250 (as low as the 7800 will let the mids go) and the low pass up to 4k. Absolutely amazing, midbass and voices just came alive!

On the install, I obviously ditched the ridiculously huge outer bezel, slotted the door card for the chrome inner bezel/grill's tabs, mounted the driver to the inner mount and installed that inside the door card with the inner bezel outside the door card poking through the whole assemble. I think some modification to the door card's mounting holes was necessary. In both cases I used a Milwaukee 12v vibrate saw with a small not terribly aggressive blade. You'll see when you get all the bits laid out.
Awesome, thanks for the info! I believe the Sedans/Wagons (my car) have slightly more depth in the doors.
 

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Yep, somewhere in that range depending on slope.



Keep in mind your driver side mid will be significantly more off axis than your passenger side. Picking a speaker with smooth FR, both on and off axis, will make it easier to achieve a matched L/R frequency response in the car. So basically... use speakers in the proper pass band (before beaming) whenever possible.


I suppose ideal is like 2500hz if you want to take into consideration the beaming effect - you would then need a tweeter that is comfortable at 2500hz which should not be too hard to find as most Scan tweeters have a FS of 500hz (for example)


Sent from my iPhone using Tapatalk
 

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Behind. Let me know if you see a better way. Not entirely sure I did it as God intended.

I have them high passed at 125 hz and low passed at 6.3 khz. Also turned down 4db.

Rugrat just got home with the e92 from his Organic Chem II class so I played the Lyle Lovett track Andy mentioned in that and then played it in my moose that has the mids and tweets up on the A pillars. No comparison. The GB40 imaging and impact are phenomenal.
 

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Hey folks, I thought this might be a good thread to post this video on. In the video I'm explaining a bit about a little known (in car audio circles) measurement called coherence.

Coherence can aide in the determination of crossover points based upon the direct to reverberate ratio of sound at the microphone position, or in the case of Smaart 8, at multiple microphone positions.

The coherence reading will be affected by speaker positioning, aiming, beaming, and the direct to reflected energy ratio on a per frequency basis.

It can be used especially in aiding tweeter and midrange placement and aiming during installation as well.

I plan on also doing a video of coherence using ARTA.

https://youtu.be/N3WcEVtAJM8
 

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Some good info in this thread. I'm kinda torn between better tweeter aiming. To many people generalize the terms with on vs off axis. So many different aiming tactics like one off axis and one on axis. Both aiming towards the center line or both aiming towards the headliner. I see so many different tweeter positions from audiophiles. Seems alot of tweeters benefits from very slight off axis aiming, that 15-20 degree area for bright tweeters. Am I safe to say that even at 30+ degrees that it can be EQ to sound just as good and less EQ with on axis. Meaning if someone wasn't going to install a dsp the benefits of on axis are greater. If someone is going to tune by dsp than a 15-30 degree off axis placement is ok because of tuning capabilities. Either route I see there will be reflection somewhere in the car. Which we all know is a horrible acoustic environment. I expect honestly a true on axis in your face tweeter aiming would need alot more toning down by dsp. A more perfect tweeter install would be more towards both aimed at center line or towards the center headliner area. When listening to opinions alot of people like off axis overall sound. Is this because this tones the high end of the frequencies down and they are using bright tweeters without dsp tuning?

Just my thoughts, let me know if I'm in the right ballpark with my comments.
 

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Hey folks, I thought this might be a good thread to post this video on. In the video I'm explaining a bit about a little known (in car audio circles) measurement called coherence.

Coherence can aide in the determination of crossover points based upon the direct to reverberate ratio of sound at the microphone position, or in the case of Smaart 8, at multiple microphone positions.

The coherence reading will be affected by speaker positioning, aiming, beaming, and the direct to reflected energy ratio on a per frequency basis.

It can be used especially in aiding tweeter and midrange placement and aiming during installation as well.

I plan on also doing a video of coherence using ARTA.

https://youtu.be/N3WcEVtAJM8
Not understanding this. Beaming is the point at which the on axis response and the off axis response begin (and continue as frequency increases) to diverge. So, at frequencies where the dispersion is narrow, there's LESS contribution from reflecting surfaces.

What are you using for the reference trace and are you using your spatial average as the other trace?
 
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