DiyMobileAudio.com Car Stereo Forum banner
1 - 14 of 14 Posts

·
Registered
Joined
·
383 Posts
Discussion Starter · #1 · (Edited)
I apologize in advance for my lack of knowledge. Tweeters are pretty much the only thing in car audio that is greater than me. I know SOME about them, but not a whole lot. When you guys think "Well, they're just like any other speaker" I know what you mean, but this whole "in-phase, out of phase, on-axis, off-axis, invariable mount capacitance (ok I made that last one up :p I think....... lol)

Anyway. I drive a '99 S10 (build in the sig) and I've got the Boston Pro60SE's for my front stage in custom fiberglass kick panels that I made myself. I had the tweeter mounted "on-axis" (this is what the manual told me....) with the woofer, mounted right "on top" of it. The sound stage was really low, with all the sound coming from my legs. So chadillac suggested that I move the tweeters to the dash, so I gave it a try. I completely LOVED the raised sound stage. It was comparable to my friend's car (s10's small, cramped cab isn't the greatest for that sorta thing) which I was really happy with.

So now I want to get creative. I've got some decent fiberglass skills (see: build thread) so I want to mount the tweeters into the a pillars. Well of course I'm not just gonna dive in and start glassing. I want to/need to get the correct placement and angle of the tweeters first. That's where I need the help.

I know you guys can't physically hear what I'm hearing, but some definitions on some terminology would be awesome. And, of course, I'm always open to suggestions as well.

Here is the "pod" I made for the tweeter. There is a big ass washer in the back with a screw to hold it in place. It's secure in the pvc.





So when you guys say "on-axis" does that mean that the tweeter is pointing right at the driver? (human being, not speaker)

Like this?:




And then "off-axis" would be this?:





Right now the tweeters can just be too harsh, and they aren't level at all. I have the tweeters attenuated at the crossover to -4db, but even then, with the tweeters still at the a-pillar, they still seem too harsh (bands 6-10 on the EQ are turned down even). Sometimes they will be just fine with some slight movement or adjustment on the dash (just laying them there) but others can be quite sharp. I just don't physically know what the "on-axis" and "off-axis" techniques do to the sound of the tweeter. If I knew that, then I would probably be set on my own. This is what I'm trying to accomplish. A balanced sound while mounting them cleanly in the a-pillar.

So, with that being said, generally, what are the advantages and disadvantages of having the tweeter mounted on-axis or off-axis? You can get as detailed as you'd like, or a 3 word answer. I just kind of need a general idea of where to go from, because right now I'm kinda just stabbing in the dark as far as the location and angle of the tweeters should be. With a point in the general direction, I should be able to go from there.



One last thing.....

In your guys' opinion, should I have the left tweeter facing the driver, and the right tweeter facing the passenger, or have the tweeters "cross" each other, with the left tweeter facing the passenger, and the right tweeter facing the driver. Or go both "off-axis" (I think?) and have the tweeters point right at each other and have the sound "meet" in the middle of the dashboard.

Also, in-phase and out-of-phase. Is that just physically reversing the polarity of the tweeter? I've read that it will give me some type of sound delay, sound about right?


I really do apologize for the long post, I know most of you guys are gonna be like "use google...." or what not, but some opinions from this site would be very helpful, and GREATLY appreciated.

Thanks again everyone.
 

·
Registered
Joined
·
172 Posts
You have the on axis/off axis placements correct. If they are too bright then yes you can typically have them off axis to tame some of it, but you have a lot of reflection issues going on. Firstly if I was going to run them on the a-pillars I'd raise them up a bit so they fire above the hump in your dash. Also a dashmat would do you wonders as it'd clean up any of the dash reflections you may be getting. Then of course there is the windshield... You can try angling them slightly more on axis to reduce the windshield reflections and even aim them up towards your dome light as well.

Personally I've found that sail panels work better than a-pillars for soundstage width and reflections, but not sure if that's an option for you. Also if you plan on mounting them as they are in your pictures you will lose even more soundstage width so I'd say putting them inside the a-pillar would be superior.

Lastly the phase issue you're speaking of is wiring each tweeter out of phase with one another. This creates a slight time delay between the tweeters, but with all those reflections going on you are going to have phase issues already and wiring them out of phase may not do much for you. Also you can wire the tweeters in phase with eachother, but out of phase in relation to the mids. Best thing to do is simply try them wired differently until you find the right sound. Wire them both in phase and out of phase with the mids, then once you decide how you like it you can swap polarity of one tweeter and see how that goes.

I highly recommend a dashmat if you're putting tweeters up high as that alone can help out a lot of reflection issues which might tame the brightness. My guess is if they're that bright even with a -4db attenuation then you might be getting some sort of frequency boosting at key frequencies due to reflections and the dashmat may fix that.

One more thing, depending on where you cross your tweeters the phase may not matter. Higher frequency localization is attributed more by volume than by path length issues so making sure the tweeter closest to you is the same volume as the farther one is more important than having them phased to induce a time delay.
 

·
Registered
Joined
·
6,848 Posts
The "harshness" you may be hearing can come from a number of different things. Mostly because "harshness" is a pretty vague term, so it's hard for us to identify what bandwidth the problem is occurring in.

Personally, I'd just take some velcro and stick the damned things all over the car until you find a general location/aiming that you like. As the other guy alluded to, reflections could be f-ing you up the ass here. Don't be afraid to experiment with potential mounting locations, including upper doors, sail panels, kick panels, or wherever else you feel you could fabricate a housing for them.

From an electrical standpoint, play with the polarity of the tweeters relative to the midranges. Sometimes "harshness" can arise due to peaks at the xover point. You can also consider biamping so that you can tame these brutes with level controls and crossover adjustment.

If the tweeters are intrinsically just too damned bright, as many BA tweeters have been accused of being in the past, you might find some relief by mounting them a bit off-axis. If all else fails, you can also try to find a foam to actually put over them (or around them, if diffraction and local reflections are screwing you up). I've actually had good luck in the past attenuating the upper octave or so by doing that.
 

·
Registered
Joined
·
172 Posts
I agree that if they are just too damned bright some sort of cloth/foam in front of them may help. Normally this would cut out too much of the high frequencies on a typical tweeter, but on a super bright tweeter it may do just fine. I'd also recommend wrapping the a-pillars in grill cloth to help with reflections. Hell I'd try a couple layers of grill cloth directly over the tweeters or maybe make a foam ring around the perimeter of the tweeter that sticks out and then aim them off-axis.

There is no simple answer, just try moving them around in different configurations until it sounds how you like it. And be sure to leave them EQ flat while doing this and once you find the best placement you can EQ them to tame anything left.

Try this... use the velcro as MarkZ mentioned and mount them in different places. I'd try a couple inches above where you have them pictured aimed off axis. Place a towel across your dash to serve as a ghetto dashmat to help with reflections. Then if they're super bright still try placing some sort of fabric/foam attenuation by just taping it between you and the tweeter. You don't have to cover the actual front of the tweeter, just a square of material that blocks some of the output from the side.
 

·
Registered
Joined
·
383 Posts
Discussion Starter · #5 ·
Wow awesome replies guys. I really appreciate your time in reading the thread. I know it's a lot.

I think I'm gonna try and move the tweeters up the pillar more and see how that goes. The velcro idea is a great idea.

I had a feeling you guys would say "you just have to experiment" which I totally understand, but the suggestions you guys give do help me out a lot. It gives me a structure to build off of.

I'll update as I start testing. Maybe another s10 owner could benefit from this as well.
 

·
Registered
Joined
·
383 Posts
Discussion Starter · #6 ·
Also, in the end, my goal is to have the volume on the headunit set to 25 (this is where my gains are set to, also it's my "cranking" volume) with no brightness or harshness in the tweeters.

I know you guys are into SQ with the "not so high" volumes, but I do like to listen to it loud sometimes, and my goal is for it to sound great at those volume levels.

Thanks again everyone.
 

·
Registered
Joined
·
172 Posts
Actually I've always attributed at least "part" of SQ to be the ability to play loud and remain composed. This may not be a true component of SQ but nothing gives me goosebumps in my ride more than being able to crank it up loud and hear no strain from the speakers.

What can be better than Lateralus at full tilt?
 

·
Registered
Joined
·
383 Posts
Discussion Starter · #9 ·
Then you don't know me at all. :D

Keep us posted.
lol

Actually I've always attributed at least "part" of SQ to be the ability to play loud and remain composed. This may not be a true component of SQ but nothing gives me goosebumps in my ride more than being able to crank it up loud and hear no strain from the speakers.

What can be better than Lateralus at full tilt?
^that's my goal here. You took the words right out of my mouth.
 

·
Registered
Joined
·
45 Posts
Instead of using velcro, I recommend BlueStik. It's a reusable sticky putty that is made to hang posters, pictures, etc. on the walls of your home. I found that it's a lot easier to work with instead of having to remove strips of velcro and worry about the residual it might leave. You can find it at any hardware store.

BlueStik
 

·
Registered
Joined
·
383 Posts
Discussion Starter · #11 ·
Instead of using velcro, I recommend BlueStik. It's a reusable sticky putty that is made to hang posters, pictures, etc. on the walls of your home. I found that it's a lot easier to work with instead of having to remove strips of velcro and worry about the residual it might leave. You can find it at any hardware store.

BlueStik
Awesome, thanks for the tip :)



Here is Test #1:












This is definitely BETTER than what I had before, so we're gonna go from here.
 

·
Registered
Joined
·
172 Posts
You're not the only one still experimenting. I've been messing with a 3 way and am pretty happy with my locations now but these NX30s are just too damn big for my sail panels so I'll probably be looking for a smaller format tweeter to place there. Crossing at 8k right now so I can go tiny if needbe.



Anyways.. not sure how much you want to get into your setup but man many would kill to have those dash locations. They seem to work well for 3-4" mids firing up and then having tweeters in a-pillars or sail panels. Once I got this dialed in I don't think I could go back to just a tweeter.. Mids are playing from 200hz and up and my soundstage is as high and far forward as I've ever heard in any of my cars. Absolutely at my eye level and sometimes I get cymbals crashing that sound higher up not to mention it sounds like it's beyond my windshield.
 
1 - 14 of 14 Posts
Top