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Discussion Starter · #1 · (Edited)
As per topic, I am running a 2005 Subaru Forester, I have a set of JL Audio ZR splits in the front doors. The tweeters are in the sail panels behind the mirrors. I am currently using the factory headunit, until I decide what NAV screen to buy. So there is no external amps, processors. Just the JL Audio passive crossovers

My problem is, I cannot get a centre image, UNLESS I wire all the entire system out of phase, then its centre image is pretty good. But, the system sounds like horrid with no dynamics or impact.

Connected correctly, the system sounds tonally pretty good, nice dynamics and a very clean sound. But no centre image.

I have even moved the tweeters from the OEM location which is normally cross-firing aimed at the opposite headrest., currently the are in OEM locations on the mirror sails, but now cross firing at each other. Still no joy!! Even tried connecting them out of phase to help.. no joy. The weird thing is, tweeters in phase or out of phase there is no audible difference. The sound stage does not change

When listening to the Left, Centre, Right channel test from drivers seat. Left is accurate and nicely spaced on LHS, centre is on my speedo cluster, RHS is just besides me. On LHS this is complete mirror image of the drivers side.

I am banging my head against a wall here. As I know a car with tweeters behind the mirror sails can and should have a decent centre image.

I am guessing there is some weird cancellation in play, but I have really no idea where to start!
Any ideas??
 

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Have a look at the axis of the door mounted speakers relative to your sitting position.
 

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Read all the alpine Type-X (old and new, ref, pro etc) component speaker manuals.
A lot of them are on crutchfield.

They give decent strategies for dealing with various speaker locations using phase
and attenuation. For instance you may want to wire just the passenger side tweeter
out of phase depending on the setup.
 

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Hate to break it to you, but with a 2 way set up in stock locations and no T/A, you are not going to get a very good image. You are adjusting the tweet location, but the mid has a ton of imaging queues that you are neglecting. Only good way to get a solid image in a 2 way is a lot of processing or kick panels.
 

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(The weird thing is, tweeters in phase or out of phase there is no audible difference. The sound stage does not change)

tweeter phase doesnt matter. wavelengths are too short
 

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tweeter phase doesnt matter. wavelengths are too short
Yes it does. I'll prove it to you at the next meet. Time aligning tweeters is also useful. Amplitude plays a big role but arrival time will screw you every time.
 

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As per topic, I am running a 2005 Subaru Forester, I have a set of JL Audio ZR splits in the front doors. The tweeters are in the sail panels behind the mirrors. I am currently using the factory headunit, until I decide what NAV screen to buy. So there is no external amps, processors. Just the JL Audio passive crossovers

My problem is, I cannot get a centre image, UNLESS I wire all the entire system out of phase, then its centre image is pretty good. But, the system sounds like horrid with no dynamics or impact.

Connected correctly, the system sounds tonally pretty good, nice dynamics and a very clean sound. But no centre image.

I have even moved the tweeters from the OEM location which is normally cross-firing aimed at the opposite headrest., currently the are in OEM locations on the mirror sails, but now cross firing at each other. Still no joy!! Even tried connecting them out of phase to help.. no joy. The weird thing is, tweeters in phase or out of phase there is no audible difference. The sound stage does not change

When listening to the Left, Centre, Right channel test from drivers seat. Left is accurate and nicely spaced on LHS, centre is on my speedo cluster, RHS is just besides me. On LHS this is complete mirror image of the drivers side.

I am banging my head against a wall here. As I know a car with tweeters behind the mirror sails can and should have a decent centre image.

I am guessing there is some weird cancellation in play, but I have really no idea where to start!
Any ideas??
Place the tweeters lower (closer to the mids), then flip the polarity of the right speaker system (at the crossover input). Then set the sub/mid crossover point at 80 Hz/12db/oct. and play with the subwoofer polarity to get the best midbass transition and up-front bass effect.

It probably won't be perfect, but I think it will be a lot closer to being right.

Good Luck.

Manville Smith
JL Audio, Inc.
 

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You probably won't be able to, especially if you expect it to have a center image and 3-d soundstage like with a decent home setup in a decent room. They have whole articles about this in the Journal of the Audio Engineering Society. For you to get proper soundstage, you'll need:
a) equal time arrival, so you'll need t/a
b) similar freq resp curves for your L and R channels, so heavy EQ for each channel
c) and once you got a and b, the big one is you have to eliminate REFLECTIONS. It's been shown that the sound from the R tweeter will bounce off your driver's side glass, and produce an equally loud sound in to your LEFT ear. Ive done sine sweeps from individual channels and heard certain frequencies are perceived from both ears and somestimes from the OPPOSITE side! It's because of the heavy reflections from all the glass in your car. If you want better soundstage, drive a convertible with the top down...or at least open your front windows and sunroof.

One solution go b and c is to use digital room correction that uses a calibrated mic and DSP to eq your whole system and correct for reflections. It's a big improvement and not all implementations of it work as well. I believe Alpine does something like this.

Alternatively, you could just shoot for what most people are satisfied with car audio, and that is a balanced soundstage that runs from left to right and across the windshield and that's it.

SG
 

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Phase is a usable bandaid to partially get around the need of time alignment. I too own a Subaru Forester, an 02 S, and my bro too, an 04 XT. The biggest problem you have is time alignment. The second biggest problem you have is the difference in off-axis angle between the near and far woofers, 30 degrees on the far woofer, a high 60 degrees on the near woofer. What you get is a difference in frequency response in the midrange and this too messes up imaging (after you've corrected with time alignment.

Basically, you're stuck. Until you're willing to buy a HU or processor with 3-way x-over capability and time alignment, you can't do much. As well, unless you're willing to play with aiming the woofers using custom pods, you're also stuck needing separate EQ for the left and right sides.

I suggest you start thinking about grabbing a Pioneer P880PRS(old)/P800PRS(new) HU and a 4 channel amp. Basically the HU's front outputs go to channel 1 and 2 on the amp and then to each tweeter. The HU's rear outputs go to channel 3 and 4 on the amp and then to each woofer. You have separate volume and time alignment control for each single driver as well as a separate left and right 16-band EQ to fix the off-axis roll off differences and even out the response between both sides. Until you do this, you can't get a good center image. It simply won't happen. When you do eventually do this, everything will be really, really good.

The only other thing to address is cabin noise, although, the newer models(03+) are a big quieter then my older gen 02. It's quite useful to dampen out the vibrations in the doors. Any panel vibrations makes noise and brings your attention to that location, making good transparency difficult.
 

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Hmm - I have kind of mixed feelings on the answers I was seeing here after all the time I have been on this site reading, thinking, and trying it. Maybe I am in one of those moods. Anyway, this is what I found worked for me and would recommend doing the same - I just went through all of this and know the pain.

If you haven't done it already, pull the tweeters and keep them loose, add some extra wire to them - like a couple feet. Go down to WallyMart or whomever and buy a couple packages of those 1" square Velcro style fasteners. Put one side on the back of the tweeters and plaster the interior where you think would be possible locations for placement with the other side of the velcro schtuff. Along the A-pillars you might have two or three spots alone. Then the sail panels, the top of the dash, under the dash, all the usual places and maybe some unusual ones too - I have seen tweeters done in the AC vents that worked very well. My car had black squares everywhere and people looked at it funny... Then, start with the tweeters at one point. Listen to them for about 10 - 20 hours. Then move them to the next spot and do it again, until you have listened to every position. Try different angles too as this can make a lot of difference. Somewhere you will find that magic spot where everything just starts to work in harmony.

I did this in my car and finally found the sweet spot was under the dash pointing towards the opposite seat. Yeah - it took hours and hours - and I am at the luxury of being in my car 10 hours a week minimum, so I had lots of time to kill doing the critical listening. I did this for several months and it paid BIG dividends. In the process I found I could try a location, say in the pillars about mid way up, firing across and would have good imaging but a very narrow stage. Then try them in the sail panels and have a very wide stage but low and it wouldn't keep focus. Some other spot would seemingly get "two" stages split in the middle. Once I tried everything up top, I tried under the dash and the location and angle they are at now has a stage a little above the dash, it is fairly wide on the drivers side - beyond the left pillar and way out to the right somewhere. It does not lose focus at all. EQ is very minimal - probably use more EQ to shift the center of the stage than to boost/cut response and even then everything is in the range of 3dB worst case if that.

Was it worth the time? Hell effing yes. I admit I might have got lucky. At times I thought of giving up. It is finally starting to sound like what I want it to sound like. Now I have to fix a few other things, build a permanent amp rack, deaden the car, and get the midbass drivers properly installed and it should be done. And then I may be in audio bliss thanks to everyone on this site and the DIYMA attitude that at least used to be present.
 

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Discussion Starter · #15 ·
Thanks for the advise, I have taken it all on board, a new headunit and processor are in the works; when $$ allow.

Just one thing still sticks in my mind, we have a Mazda 6 at home with the premium Bose system which has nearly the same setup as my car. Mids in the doors and tweeters on the mirror sails. This has a centre image. When listening to the test track, when the female voice says she is currently centred... she is in the Mazda, whereas in my Forester she is ontop of my instrument cluster??

How come the Mazda can image with no TA and mirror sail mounted tweets and I can't even get close??

Sorry for the dumb questions, I just get around this.
 

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Thanks for the advise, I have taken it all on board, a new headunit and processor are in the works; when $$ allow.

Just one thing still sticks in my mind, we have a Mazda 6 at home with the premium Bose system which has nearly the same setup as my car. Mids in the doors and tweeters on the mirror sails. This has a centre image. When listening to the test track, when the female voice says she is currently centred... she is in the Mazda, whereas in my Forester she is ontop of my instrument cluster??

How come the Mazda can image with no TA and mirror sail mounted tweets and I can't even get close??

Sorry for the dumb questions, I just get around this.
Mazda cared.
 
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