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JBL 660 GTI

3K views 16 replies 4 participants last post by  e39 touring 
#1 ·
Holy moly, these rock!



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#5 · (Edited)
Next week(wife leaves town and I’ll work toward my first 3way (front stage - get your mind out of the gutter)



They’ll go in the OE kicks, which should bring my sound out!


Using adapters like these:



...and the money shot. Honestly looks better in person, and probably if I cleaned my dash a bit!
(Guess what brand trim ring that i?.....hint: not Pioneer)
Anyone have a P99RS remote FS?! LOL




Thanks for watching!


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#9 ·
Thanks!
Go cabrio! Do you Tune with roof open and windows down?

I took it a step further and tune outside - no garage wall reflections.


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#7 ·
Sorry but you will have far better, like infinitely better... midbass with the jbls in the kick panel! You will now have overlapping phase issues from the mids in the kicks and the jbls in the doors... I wouldn’t think twice about putting the jbls in the kick panels IB
 
#8 ·
Please elaborate.

These are too hefty for my kicks - the pods and the JBLs that reside in them produce intense midbass..... And I’d need new door cards to go back.
The pods aren’t just screwed to the cards, they are very solidly mounted to the door metal, which is deadened. CCF MLV etc. midbass is NOT an issue.

So what are these cancellations you speak of?

I’m pretty certain this is a somewhat typical 3way arrangement.

L in doors
M in kicks
TW in sail

I’m an engineer, so don’t worry about getting too technical - I’ll follow.... I want to know. Planning to add the mids to the equation this week!


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#12 · (Edited)
I for sure tweak on the road. One of the reasons I went for P99.
During main tuning, however, I was amazed when I parked outside of the garage. I also sat in the seat FWIW.
If you think about it, a cabrio has less reflections...perhaps the old “don’t waste your time with a cabrio system” is horse ****. I think they have SQ potential.
Just need plenty of power, my cabrio is the most powerful of my 3. Although it doesn’t require a ton of power for a car with a cabin. My 2005 Scion TC only has an Eclipse EA3532 5ch (4x40 + 120w) and sounds so wonderful. I have a feeling they under rated that series though. My 12” pounds.

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#13 ·
I will illustrate...

phase as measured with smaart from door mounted midbass vs a kick or under seat will look something like this...

275915

That’s an underseat midbass, playing with mids from memory... note how both traces of left and right overlay and they will also sum with 6db as they are so similar in timing and phase, nowt how flat (straight) the phase response is (you can clearly also see the phase issue just above the crossover (200hz) that’s minimal at 230hz) on the midbass, I try and keep phase issues away from main passbands and away from crossovers if majorly big wrinkles!

Now look at a typical door mounted midbass

275916


the orange trace is a sub, the blue and green is door mounted left and right midbass... yes they really do swap phase at the ears due to room modes and reflections higher up... so whil you can get the sub to play nicely with the midbass at the crossover region, it’s more or less impossible to get food phase coherence and summation through there useable bandwidth... and crossing to mids at the top end will be almost impossible as the phase of the two will be different...

to get the mids correct you will have to get both mids in phase (and therefore time) Throughout there pass band... so how can you get mids in phase and also cross to mid bass that aren’t in phase and do it well? You can’t...

midbass are the hardest drivers to sort the phase with due to the longer wavelengths involved so it makes sense to put them somewhere which by nature has less phase issues... it doesn’t matter how well your doors are deadened or built, or what time alignment/phase adjustment you use you simply can’t correct for an installation that is not good for phase in the first place

I hope that makes sense and the pics show it well...
 
#15 ·
Now look in 1/48 octave below 300hz... 1/3 or 1/6 hides all manner of fudges and can serve to make you boost freqs that simply don’t need it...

As an example you have a -12db hole that’s only 5hz wide at 86hz...

you look at this with 1/6rd octave resolution and the band covering that frequency that’s effectively flat around the dip now shows up as being -4db As the high q dip pulls the rest of the band down, so you then add 4.3Q 4db boost at this frequency, the response goes up by 3db, but in reality you’ve just boosted the flat section by 4db, the cancellation just cancelled the direct sound some more and stayed at -12db... now it sounds peaky...

may point is always look in detail first, then decide what you will cut and boost after you know what will effect your listening position negatively and what won’t hurt...

avoid boosting areas with narrow Q dips as it will mess with the sound, but you’ll miss those without decent resolution, the same goes for higher up the spectrum... narrow Q dips effect 1/3 or 1/6 octave less as the dip as a percentage of the total bands area is way less 👍🏼
 
#17 ·
Yes, it needs work. It was just nice that my first real attempt was somewhat successful....matching a target, blending drivers in my first 3way.


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