2012 Charger - Veronica

[pocket5s]

You know the saying, once you go floor...

What about a pic of where they are aimed exactly? Can we have that? Please?

Here it is in my first test, which is slightly off axis. camera is right at the head rest. the graphs above were direct on axis. The response was slightly different but not vastly so.

*coughdashboardcough*

You mean something like this??





Those are the JL 4's that arrived yesterday and I put up there to see possible fitment. I will be measuring those up there, however my dash has some issues. it is fairly flat and big, so I suspect I'll see combing issues there too. But it is still worth measuring. I even had the wild thought of cutting the flanges on my 5's and putting them on the dash. Might be worth measuring that too...

Oh, why cut them? well meca has this silly rule about dash pods can't be more than 4.5" from the dash surface, and I'm not going to the extreme class any time soon. Having said that, I can foresee a day when the dash comes apart and the sawzall case gets opened up

[captainobvious]

I'm sure you may know this already, but might I make a suggestion?

If you will be using a tweeter in conjunction with the midrange, you will not need to have the midranges aimed on axis. Place the mid 90 degrees off if you want, doesn't matter. Cross the midrange over before beaming (which in a 4" and depending on actual radiating diameter, could be around 3Khz) and it will still have even response on and off axis. This will allow you to keep a-pillar pods much less distracting visually and take up less space. Same for the kicks. The only thing you have to worry about (and test) will be how the response is affected by comb filtering from the reflections of nearby hard surfaces.
That's the challenge with the dash area. Doors pose much less of an issue, but sacrifice some depth due to proximity, and then you have kicks. A good location for PLDs, but can be a serious issue if you mount your tweeters down there because of blockage of the sound from legs.

[decibelle]

Your first pic looks as though the plug is aimed right at the steering wheel. What's it look like aimed directly at the camera, or more towards the dome light?

If you wouldn't mind throwing them up on the dash a little further forward and aimed at the dome light, I would be quite curious to see how your RTA data compares to mine. Even if you have no intention of ever putting them there, I would be interested to see the differences and similarities in response. Your dash and windshield rake are actually not too different from mine. I wonder...

The response was slightly different but vastly so.

Also, whut?

[pocket5s]

I'm sure you may know this already, but might I make a suggestion?

If you will be using a tweeter in conjunction with the midrange, you will not need to have the midranges aimed on axis. Place the mid 90 degrees off if you want, doesn't matter. Cross the midrange over before beaming (which in a 4" and depending on actual radiating diameter, could be around 3Khz) and it will still have even response on and off axis. This will allow you to keep a-pillar pods much less distracting visually and take up less space. Same for the kicks. The only thing you have to worry about (and test) will be how the response is affected by comb filtering from the reflections of nearby hard surfaces.
That's the challenge with the dash area. Doors pose much less of an issue, but sacrifice some depth due to proximity, and then you have kicks. A good location for PLDs, but can be a serious issue if you mount your tweeters down there because of blockage of the sound from legs.

Well, it does matter and that is why I posted the graphs. You can see the huge differences between on-axis in the floor and off axis in the door. The door panel itself was not a huge contributor to the response, nor was the speaker being off axis so much, but in this vehicle where they are it is. The transmission tunnel alone is huge, so between that, the bottom of the dash and the seat, I get the response you see in the first graph. Big comb filtering issues basically (like you mentioned for a dash setup).

Now, with the speaker in an anechoic like space, no it won't matter, but in car it is obviously of not much help. While I didn't post it, there are even differences, albeit slight, between direct on axis and slightly off. the environment just has too much in it to not be affecting it in some way.

If I can locate and aim them in a manner that doesn't not overly compromise height and width and gives me a much smoother frequency response without eq, then that will be my likely choice.

I wouldn't be putting them in the kicks for PLD purposes though. It is a single seat car so PLD is not much of a concern given DSP these days. I should say that while I say "kicks", it is really the floor area just a tad in front of the kicks. Most of the kick area is taken up by the midbass, and those definitely aren't moving.

The tweeters will 99% likely be staying where they are in the sails (you can see it in post 101) and they are capable of playing from 2500hz and up, which is right above the beaming point. On axis on the mids would give me a little more leeway to go up if need be as these speakers are pretty smooth up to 4k-5k where they then break up, so I have some flexibility in tuning that range, where most tweeter are 5k and up (give or take).

Your first pic looks as though the plug is aimed right at the steering wheel. What's it look like aimed directly at the camera, or more towards the dome light?

If you wouldn't mind throwing them up on the dash a little further forward and aimed at the dome light, I would be quite curious to see how your RTA data compares to mine. Even if you have no intention of ever putting them there, I would be interested to see the differences and similarities in response. Your dash and windshield rake are actually not too different from mine. I wonder...



Also, whut?

yeah, I meant "not" vastly no (corrected original post)

That pic was the first that I took and while it is hard to tell given the angle, the speaker is just about parallel to the bottom portion of the dash, but yes, it is basically aimed through the steering wheel and almost to where the dome light would be. Just to be clear, the measurements given were directly on axis though.

I actually plan to measure it on the dash, if for no other reason than curiosity and the speaker wire is long enough as it is. I actually thought yesterday what kind of effort it would take to cut the flange off these 5's, angle them back some and put them on the dash. why? well, meca modex has this silly little rule about dash pods not being more than 4.5" off the dash surface And I'm not moving back to extreme any time soon.

I will also be measuring my 4's on the dash for comparison sake. Initially up on the dash, on or semi-on axis. If I can get them in the factory dash corners without too much trouble I'll measure them there as well. I'll post up all those pics tonight.

I also plan to pull the passenger side speaker out, get it wrapped up and start seeing what the combined responses look like, and well as sound like. Width is my biggest concern at the moment, height 2nd. Either way I'll probably spend the next couple weeks playing with them and listening to decide which is the best route for me for this season. The College Station show is coming up so I can't goof off too much between now and then

[erinh]

the subtle differences you're seeing can also be chalked up to the RTA method, as you are probably already aware. Obtaining a legitimate apples to apples with RTA software is very tough. That's why I'd stick with impulse if that's what you're trying to achieve. Then you can gate the responses to be time matched to a 't', and in relation to the distance the speaker is so you're not catching all the other stuff going on. moving the mic just a touch can result in different results; and measuring just a touch longer in time will have the same effect in our car environment. just some input that you probably don't care about at this point.

I think your aiming is fine. I would, too, not aim them across the dash. Cross firing opens up a bag of worms and while beaming isn't until around the 3khz, that's assuming a 1/2 wave pattern. You have to worry about the radiation of the speaker itself but also with respect to how it interacts with your tweeter. Some home audio guys will use 1/4 calculation to determine the maximum delta between tweeter and mid for this reason. There's things about the radiation of a speaker that I can never quantify with words, fully. And when I try it sounds like hocus pocus. Suffice it to say, unless the design calls for it or the speaker has poor behavior on-axis within 30deg, I'd not fire them across the dash at 60-90deg off-axis. You'd be opening up a can of worms that is going to be tougher to correct.

Final, FWIW: Since you took the time to point out the differences, I wanted to say I actually measure with my body in the seat in most cases. I just tilt the mic up and lean the seat back a couple extra inches so I can move the mic around in the head area. The aiming of the mic toward the roof only affects HF roll off above about 8khz and I tune HF by ear anyway. Below that, the mic electet is practically Omni so it works well.

Anyway, good work so far, man. I know you're getting your help from Todd but if you want to venture in to REW (which I recommend to death) then LMK and I'd be happy to help you get set up. Ally can attest to how easy it is to use.

[pocket5s]

the subtle differences you're seeing can also be chalked up to the RTA method, as you are probably already aware. Obtaining a legitimate apples to apples with RTA software is very tough. That's why I'd stick with impulse if that's what you're trying to achieve. Then you can gate the responses to be time matched to a 't', and in relation to the distance the speaker is so you're not catching all the other stuff going on. moving the mic just a touch can result in different results; and measuring just a touch longer in time will have the same effect in our car environment. just some input that you probably don't care about at this point.

I think your aiming is fine. I would, too, not aim them across the dash. Cross firing opens up a bag of worms and while beaming isn't until around the 3khz, that's assuming a 1/2 wave pattern. You have to worry about the radiation of the speaker itself but also with respect to how it interacts with your tweeter. Some home audio guys will use 1/4 calculation to determine the maximum delta between tweeter and mid for this reason. There's things about the radiation of a speaker that I can never quantify with words, fully. And when I try it sounds like hocus pocus. Suffice it to say, unless the design calls for it or the speaker has poor behavior on-axis within 30deg, I'd not fire them across the dash at 60-90deg off-axis. You'd be opening up a can of worms that is going to be tougher to correct.

Good points. I never specified, but the rta was done with a 50 averaging and with the exception of the one measurement of the direct to cone, the mic was moving the whole time.

While I do plan to see just how much of a detriment the dash is, I never really considered cross firing them. If anything, not more than 15* or so off. Like Ally had at the GTG or Cook has in his truck. Having said that, I'm really leaning towards the floor for the time being. Unless something is just drastically better on the dash setup

Final, FWIW: Since you took the time to point out the differences, I wanted to say I actually measure with my body in the seat in most cases. I just tilt the mic up and lean the seat back a couple extra inches so I can move the mic around in the head area. The aiming of the mic toward the roof only affects HF roll off above about 8khz and I tune HF by ear anyway. Below that, the mic electet is practically Omni so it works well.

Anyway, good work so far, man. I know you're getting your help from Todd but if you want to venture in to REW (which I recommend to death) then LMK and I'd be happy to help you get set up. Ally can attest to how easy it is to use.

That is pretty much what I did for my in-seat measurements. Just waved it in front of my face in as much of a 180* arc as I could.

I tried to use REW initially but I couldn't get the damn rta portion to show anything. about 20 minutes after trying I gave up and went back to True. I had used it before so I don't know what was wrong, but that was a few hours before leaving for Todd's GTG so I didn't have time to screw with it.

[erinh]

Yea. REW just takes getting it set up once and then it's gravy.

I actually have my Kefs aimed toward the center seat. So I'm on axis to the right but about 20 degrees off axis on the left. I did this in hopes that the time/intensity tradeoff would result in less needed TA and level matching, which worked out well based on what I've had to do to other set ups in my car. So off axis isn't horrible. I just wouldn't advise an across the dash firing in nearly any case. Thus my reply above.

[pocket5s]

Yea. REW just takes getting it set up once and then it's gravy.

I actually have my Kefs aimed toward the center seat. So I'm on axis to the right but about 20 degrees off axis on the left. I did this in hopes that the time/intensity tradeoff would result in less needed TA and level matching, which worked out well based on what I've had to do to other set ups in my car. So off axis isn't horrible. I just wouldn't advise an across the dash firing in nearly any case. Thus my reply above.

Makes perfect sense.

[BigAl205]

I was curious, what kind of mic and interface are you using?

[pocket5s]

I was curious, what kind of mic and interface are you using?

Behringer ECM8000 mic with a micmate usb interface.