# Depth of Stage, Your Tweeter, and You...



## mattyjman (Aug 6, 2009)

Ok, Question about ideal tweeter placement. Upcoming install in my BMW, I'll be running L4SE in the kickpanels... and the tweeters will be up above the dash somewhere. My original thoughts were for the tweeter to replace the factory location, sail panels. 

In location playing with the L4SE's a few weeks ago, I was able to achieve a pretty wide an deep stage, just running full range. I would like to keep that and plan to run them pretty high, possibly up to 8k or so, where the tweeters will come in and anchor the stage. So this is where my question is...

With ITD, and IAD, (all the mumbo jumbo i really don't understand), will I loose any of that depth of stage by using the sail panels, as opposed to the a-pillars? 
Here is a pic for reference... talking about maybe 3-4 inches back further, but more than likely the pillars would need to be built out a little further inward as well.

Tweets will be firing off axis

http://i282.photobucket.com/albums/kk252/m123default/BMW 335 Convertible Build/DSCN2127.jpg


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## Mic10is (Aug 20, 2007)

Depth, not likely. distance to stage--slightly.

Depth is one of if not the most misused term in car audio. Depth does not refer to how far forward the stage is from the listener.
Depth refers to the distance or space from the front of the stage to the back of the stage and in and around images. Depth quality is what gives the recording a 3D like quality.

how far the stage is from you is soundstage relative to listening position.


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## mattyjman (Aug 6, 2009)

Okay... let me rephrase then so we are clear... is this going to make the stage narrower ( front to back) than if the tweeters were in the pillars? I assume that the front of the stage would be closer to the listener if in the sail pannels, but would the back of the stage become equally closer to the listener?


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## Mic10is (Aug 20, 2007)

Measure the distance--theres your answer. at the freq you are going to run the tweets--time arrival will have a negligible effect, it will be primarily intensity


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## mattyjman (Aug 6, 2009)

And by intensity, you mean that the level at which the tweeter plays, relative to the mids, will have more of an impact than distances? ... 

Like I said this stuff sometimes elludes me...


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## Mic10is (Aug 20, 2007)

mattyjman said:


> And by intensity, you mean that the level at which the tweeter plays, relative to the mids, will have more of an impact than distances? ...
> 
> Like I said this stuff sometimes elludes me...


above 2000hz our ears rely more on intensity or amplitude ie..volume that it does for time arrival.

at 8khz the tweets dont be doing much except adding the top end sizzle and sparkle. 

Im not a huge fan of separating the mids from the tweets very far, but if you are going to do it, have a mid that can play easily up to 6khz and run the tweet at at least 5khz and up.

Keep in mind the slope as well, a shallow slope means it will be playing the freqs below the XO point more.


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## mattyjman (Aug 6, 2009)

do you foresee any issues with this type of alignment in this car?


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## mitchyz250f (May 14, 2005)

A 4" speaker will start to beam at 3K or so, by the time you are 8K they are beaming so much that no amount of eq will fix it. The pic is from a Vifa 4", but they all behave the same. 

Why do you want to cross so high? I have a question along the line of ultimate tweeter possitioning. The sail panels are wider than the A Pillars, and the angle left and right is more extreme, will that make the stage wider? Some have said it will.


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## ErinH (Feb 14, 2007)

^ that's not entirely true and not all drivers behave the exact same. I used to think so, but after doing my own testing I found it not to be true. If you look at the data I acquired (see: my own test setup) the L4SE beams around 9khz on-axis. If you do the math, you get 1.6khz beaming (based off ~diameter of 4"). The OEM data shows a bump from 1k-2khz but it's not what I'd necessarily call beaming as it's not a sharp rise in response like the one at 9khz.
Off-axis, the drivers smooth out pretty well, so 15* off is a good aiming point (it's what I went with in my car) to get that top end peak starting @ beaming and to match up with a set of tweeters a little on the 'hot' side (ie: higher gain than normal) so it grabs the upswing of the 8khz peak and carries it out to 20khz (slope @ ~12dB crossed over @ 12khz). Up to 8khz they do just fine even out to 30*

Additionally, beaming does not propagate. It's relative to the driver size and doesn't have harmonics like you're suggesting with the "@ 8khz it's only going to be worse". 


Here's the results:


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## ErinH (Feb 14, 2007)

you may be right.

Edit: I'll try to elaborate...

You are right regarding how I define it (wrongly). Beaming to me isn't so much about rolloff as it is the peak in response you get _before _rolloff. But, I certainly failed to include that beaming is in direct relation to rolloff and therefore jacked up my reply earlier. So, let me try again now that you've helped correct my reply. 

Beaming should be in the range you stated; 13500/2/(driver effective diameter). In this case it's about 2khz for a 3.5" effective diameter (half surround to half surround). My results and own listening show that there is not a dramatic rolloff at this frequency at up to 30* off axis; rather one at about 7khz between 0 and 30*. At 60*, rolloff is ~ the calculated result above begins to take precedent. This gets back to why I said "not exactly" above. While you typically have driver rolloff start at 1/2 wavelength = to driver eff diameter, it's not always as clear cut. Additionally, one can use these features if they know where it exhibits this response and they understand how they want to use it. Like I said above, I'm crossing my l4se's @ 8khz and catching it just as the top end starts to blossom. I've synced this to the tweeter's response and this has allowed to me to both cross high, avoiding the low end distortion of the tweeter, but also hit a 'target curve' a bit more easily. 

So, while beaming may be an issue to some, if used wisely it can be beneficial. Furthermore, I haven't found there to be significant issues with this particular driver beaming in my used passband (250-8khz). However, I did have the problem with the Scan 12m when fired on-axis; I had to cut it below 4khz, otherwise beaming would occur and the stage would pull right to the speaker(s).


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## mattyjman (Aug 6, 2009)

okay, another question...

when placing the tweeter on the left side... both locations are going to struggle to overcome the two dash humps shown in this picture...










would pillar locations be better than sail panels, as they can use the windshield some to disperse the sound? 

i'll do some testing on my own, but haven't yet, so i'm simply looking for suggestions and best practices. 

(i'm assuming that i'll have to invest a bit on a dash mat)


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## Big Mike (Jul 2, 2011)

Interesting read. I've been refreshing myself after a break in car audio and this helps.


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## ErinH (Feb 14, 2007)

honestly, Matt, you're much better off getting some sticky-tack (stuff you put up posters on the wall with) from hobby lobby or the like and doing some experimentation. Don't forget some banana test lead clips. 
In my recent rebuild I found the stock locations (far corners of the dash) has helped to get more depth (layered and distance from listener) than when I had tweeters mounted closer to me; above the 12m's on axis). 

Personally, I've heard MANY setups that all do things differently and some have worked successfully where others using the same methods haven't. Sometimes what you think/expect to work well just doesn't. This comes down to the environment (car) and the tune. I think you'll be much better off doing some experimentation. I toyed with center mounted tweeters (a la Patrick Bateman's thread here) and while I found the focus was _much_ better, I actually did lose stage width. I think most people would have really enjoyed it and it was going to be part of my own 'testing people' because it really did do such a good job focusing the image and the loss in width was minimal compared to the gain in focus.
Still, though, I would have actually gone with the tweeters in the center of the dash but couldn't find a way to easily access this location for install and knew that getting to them again should I need to would be a huge hassle, so I went with the stock location. 

Had I not been running the l4se's so high, I might not have been able to put them back there without losing cohesiveness in the soundstage, but I found it to work well in this case. Plus, the tweeters in my install are essentially helper tweeters and I'm not putting much weight in them in order to get the car sounding nice. 
I spent about 3 hours doing listening in various positions before deciding on what I have now (l4se's @ 15* off axis, tweeters in the dash corners). I spent an hour of that time playing with mounting them in the center of the dash at the windshield.


You guys wanna throw a wrench in to things????... consider how the baffle changes the FR, too, of your X driver. I love me some data, but I put as much stock in real listening tests as the data. The two combined can you make you _one shaaaaarrrrrp cookie_! (in the same voice I say it to my 8 month old... hoping I get a big ol' smile out of you guys like I do out of her)


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## ErinH (Feb 14, 2007)

cajunner said:


> let's not get out of hand, now..
> 
> :surprised:
> 
> ...



Totally agree. Check my edit.


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## mattyjman (Aug 6, 2009)

bikinpunk said:


> *honestly, Matt, you're much better off getting some sticky-tack (stuff you put up posters on the wall with) from hobby lobby or the like and doing some experimentation.*


i totally agree and intend on doing so... while it's 115 degrees outside, i was hoping for some brest practices... ideally that would cut down how much time i need to spend playing around with locations...

but you are totally right, every install and location can sound totally different than another...


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## ErinH (Feb 14, 2007)

for reference, here's a picture of mine (not finished)


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## ErinH (Feb 14, 2007)

mattyjman said:


> i totally agree and intend on doing so... while it's 115 degrees outside, i was hoping for some brest practices... ideally that would cut down how much time i need to spend playing around with locations...
> 
> but you are totally right, every install and location can sound totally different than another...



I had to amend my post: don't forget the banana clip test leads. 


It's hot as hell here, too. Luckily, my garage is well insulated so I put the A/C down to 68*F, closed the garage door, opened up the garage-to-house door and let the garage cool off a few hours before I started working. Next house is going to have A/C _in_ the garage.


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## mattyjman (Aug 6, 2009)

bikinpunk said:


> I had to amend my post: don't forget the banana clip test leads.


what for? these tweets have push terms...


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## mitchyz250f (May 14, 2005)

I agree that not all same size speakers beam at the same frequency. In particular some of the flat cone TB speakers show remarkable resistance to beaming.

When I used the term beaming I mean when off axis response is different than the on axis response. Some car speakers have a rising response since almost all car speaker installs are off axis. The chart you show has beaming beginning at 3 Hz. If you are trying to do a two seat car, I think that may cause some issues.

Andy always says use the speakers within their piston range (before beaming) to maintain a good power response. Poor power response can cause poor imaging and phantom even imaging.


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## mattyjman (Aug 6, 2009)

okay, beat the heat, sat in my sweltering car, and took a listen. i'm glad i did as I think i've come up with good locations now. good thing, as my top 2 options i liked the least -- sail panels, pillars off axis

so here is what i have... driver side tweeter aimed at opposite listener and tilted up a few degrees, a little bit more off axis than on axis to the opposite listener.

passenger side tweeter, on axis with the driver, tilted slightly up a few degrees. 

again, this just goes to show how important listening is before any install work is completed. i would have modified the sail panels and then been greeted with sub-par results. now i have a pretty good idea on how to proceed from here. 

here are some pics...


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## BigRed (Aug 12, 2007)

Did u try the tweeters with the same angle and some tweeking? If u don't care about cosmetics then have at it


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## mattyjman (Aug 6, 2009)

yeah, i played around quite a bit with the different locations and angles. as far as cosmetics, i think i'll be able to to mold these in pretty well. in fact, with the angle they are in, i may even be able to get these completely hidden within a new molded a-pillar. 

**small note about this install, my wife didn't want me tearing into the car that much, said that i would ruin it, and basically committed me to using the sail panels. she's going to be gone for a few weeks visiting her family out of the country... i intend on making it so she'll never know.


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## AAAAAAA (Oct 5, 2007)

I am surprised you can hear a difference at all in your stage placement with them xovered at 8khz.

That's more or less where height cues can be heared but that's a moot thing in car audio IMO since the sounds are always coming from the same height. Higher then that and it might as well be mono you are listening to as localisation is almost non existent at that point.

Here is come interesting info on depth perception.

How far away or close something sounds like has little to do with how you are hearing it or how it is being reproduced, but all to do with memory. When listening to something, we have to go back on previous experience to recognise if the sound is something that sounds far away or close by. So if you are hearing something you have never heard before and you are blinded, there is no way for your ears to tell you it's distance.

While as a known sound,for example someone speaking close VS somone from far away can be interpreted by our brain using past experience to get a ruff estimate on distance.


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## mattyjman (Aug 6, 2009)

AAAAAAA said:


> I am surprised you can hear a difference at all in your stage placement with them xovered at 8khz.


for that specific reason i didn't use a 8k crossover point, but rather something closer in the 2k region (i'm not sure exactly). 

it may sound dumb, but i'm designing this system to be as versatile as possible. let's say i get everything in and simply don't like the l4se's running so high, well now i have the ability to change up crossover points to my liking, not having to worry about location as much, as i already have taken that into consideration. if i just slapped them up there, relying on 8k as THE crossover point, then if wanted to change my mind, i'd be doing a whole new build to compensate for a better location. 

is this good practice to follow? i don't know for sure, but it makes sense to me.


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## mattyjman (Aug 6, 2009)

cajunner said:


> that location is using the dash and windshield as mild horn loading, I would be a little suspect of why the decision was made to go there other than apparent loudness..
> 
> but hey, we all have subjective shoes to fill and if stuffing a dome into the far corners is working, by all means...


how does apparent loudness come into play, when these two tweeters were the only things playing? i could understand if i had some mids playing at the same time, and moving them in the corners made them mate better with the mids, but this whole testing was done with just those two tweeters. these locations gave off the greatest sense of space, as well as a decent center. 

i'm not trying to be combative here, and i'll admit i don't know ****, but i don't understand your statement. could you qualify that a bit more?


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## ncv6coupe (Oct 25, 2009)

matt, I'm sure you have a HUGE peak in the mid highs say 8-12k. Thats what he meant by apparent loudness. Honda does it in almost all there cars now. Just look at where bikinpunk chose to put his helper tweets. They also have that very strong first reflection ala sound out on the windshield wiper pillar.


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## sqnut (Dec 24, 2009)

mattyjman said:


> so here is what i have... driver side tweeter aimed at opposite listener and tilted up a few degrees, a little bit more off axis than on axis to the opposite listener.
> 
> passenger side tweeter, on axis with the driver, tilted slightly up a few degrees.
> 
> ...


That's kind off cross firing placement and yes it works well most of the time. Play with the angles though before you do the final install. Play with angles on both axis.

It sounds better because frequencies 2k and above are more balanced with the tweets more on axis, exactly like Mic mentioned earlier in the thread. If you can take one thing from your experiment, let it be the fact that at the end of the day its about how it sounds.

It's good to know about how it measures and it's effect, but at the end of the day, it's about how it sounds. Yes, what measures better will sound better. You're never going to get perfect measurements in a car and even if you did your environment would still crap up the sound. Use the bit-1 for all it does. You're using it to tame the environment a bit and you have to hear your way through.


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## Wesayso (Jul 20, 2010)

This:


mattyjman said:


>


reminds me a bit of the Gary Summers Mercedes:









Link: 5.1 Mercedes C230 - Install Logs - Car Audio and Electronics
He later modified them a bit With a lip above the tweeter (and mid in his case) to tame reflections. He's a member here and there are pictures of this mod on this site somewhere.

Here it is:









Thread:http://www.diymobileaudio.com/forum/1264840-post101.html

Maybe it's of some help to you...


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## billg71 (Dec 17, 2009)

Just following, interesting thread...

Bill


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## mattyjman (Aug 6, 2009)

Wesayso said:


> This:
> 
> 
> reminds me a bit of the Gary Summers Mercedes:
> ...


thanks for posting that... because that is eerily similar to the image in my head that i was planning for these pillars. i doubt i would have such a large eyebrow, but i figured if i could control initial reflections off the glass, and then order a dashmat, that would kill any sort of crap the hard surfaces might generate. how to make it stealth... that's the question.


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## ErinH (Feb 14, 2007)

I talked to him a bit about those things. I don't even recall what was said, though, lol. I just know that he shaved down the dash bezel brow to cut down on reflections. And, I do know I've never heard that kind of detail in a system before. It was very, very nice. I got 3rd place to him at MECA finals with the tune I heard. Needless to say, I was happy to even have gotten that close after getting to hear it myself. Plus, the dude is totally cool to yap with.


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## Wesayso (Jul 20, 2010)

mattyjman said:


> thanks for posting that... because that is eerily similar to the image in my head that i was planning for these pillars. i doubt i would have such a large eyebrow, but i figured if i could control initial reflections off the glass, and then order a dashmat, that would kill any sort of crap the hard surfaces might generate. how to make it stealth... that's the question.


Can't wait to see what you come up with...


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## narvarr (Jan 20, 2009)

mattyjman said:


> thanks for posting that... because that is eerily similar to the image in my head that i was planning for these pillars. i doubt i would have such a large eyebrow, but i figured if i could control initial reflections off the glass, and then order a dashmat, that would kill any sort of crap the hard surfaces might generate. how to make it stealth... that's the question.


The dashmat will help A LOT. I would go as far as to say that it is a must for anyone with mids and/or tweets mounted above the dash. I just installed mine today and the difference that it makes in detail alone is more than worth the price and effort. Imaging is more stable and it moved my stage from on top of the dash to just out beyond the windshield.


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## narvarr (Jan 20, 2009)

Any updates on this?

Sent from my X10i using Tapatalk


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## mattyjman (Aug 6, 2009)

we weren't able to do what i was thinking originally, but the tweeters are conceptually in the same location. Jon installed my gear, and he posted a build log here: http://www.diymobileaudio.com/forum/diyma-member-build-logs/110941-mattyjmans-2008-bmw-335i.html


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## narvarr (Jan 20, 2009)

mattyjman said:


> we weren't able to do what i was thinking originally, but the tweeters are conceptually in the same location. Jon installed my gear, and he posted a build log here: http://www.diymobileaudio.com/forum/diyma-member-build-logs/110941-mattyjmans-2008-bmw-335i.html


NICE! Any comments in how it sounds in relation to your original question?

Sent from my X10i using Tapatalk


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## mattyjman (Aug 6, 2009)

The depth I have now is mostly contributed to how far back I have the mids ... the tweets sound good where they are and as mentioned earlier, intensity of each determines the effect that each have on the stage. I intend on getting a dashmat and I would be interested in seeing how that changes things


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## narvarr (Jan 20, 2009)

mattyjman said:


> The depth I have now is mostly contributed to how far back I have the mids ... the tweets sound good where they are and as mentioned earlier, intensity of each determines the effect that each have on the stage. I intend on getting a dashmat and I would be interested in seeing how that changes things


A dashmat should help solidify your stage and create a more focused image. It did wonders for mine, but my mids are above the dash so your results may differ.

Sent from my X10i using Tapatalk


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