# Horns and dash tweeters



## chevbowtie22 (Nov 23, 2008)

I've been doing quite of bit of reading on old school horn installs and I've seen quite few with dash tweeters. I guess I'm a bit curious of this. I'm currently running CD1 Pros in my setup and I don't *need* tweeters on the dash but I'm always open for trying something new. Especially considering I have 2 channels not being used on my amplifiers.

My questions are for the sake of experimenting what would be recommended for tweeters? Metal or soft dome? Maybe crossed over at around 12,000hz with a 6db slope? Like I said its mainly for an experiment.


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## Broshi (Jun 9, 2012)

In on this. I've been looking to invest in a solid midrange for the a-pillars to potentially better my image. I've never really thought about tweeters though as the frequency range tells me a dedicated midrange would be more suitable. That way I'll have dedicated midbass, a higher xover for the horns and the midrange frequencies should be more level. 

That's at least the assumption. Down to see what others post on this though.


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## quality_sound (Dec 25, 2005)

That would defeat the purpose of running horns. 

You can run tweeters, but if you do, only cover the area that the norms roll off at, assuming they roll off at all. If they don't you won't really gain anything. 


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## Patrick Bateman (Sep 11, 2006)

chevbowtie22 said:


> I've been doing quite of bit of reading on old school horn installs and I've seen quite few with dash tweeters. I guess I'm a bit curious of this. I'm currently running CD1 Pros in my setup and I don't *need* tweeters on the dash but I'm always open for trying something new. Especially considering I have 2 channels not being used on my amplifiers.
> 
> My questions are for the sake of experimenting what would be recommended for tweeters? Metal or soft dome? Maybe crossed over at around 12,000hz with a 6db slope? Like I said its mainly for an experiment.


This is definitely something I've considered. I think that having a crossover point in the middle of the midrange is really tricky. In my Unity and Synergy horns I can basically make it 'look' like one driver, and that fixes the issue.

But if you're *not* doing a Unity or Synergy horn, then you're going to have a handoff from your horns to your midranges around 1khz, and that's a frequency where it's really tricky to integrate two drivers.

I know that a lot of people try to figure out how to stretch the bandwidth, so that we're doing something like 500hz to 20khz with one driver. *But that's just not practical; even a $2000 TAD struggles to do that, and there's nothing under $2000 a pair that can do it.*

Once you accept that, then you start thinking of either pushing the xover point *up*, or pushing it *down*. And both solutions are valid, but really hinge on how much space you have.









On the left is the horn and compression driver that I had in my '01 Accord; it's a good example of what you can shoehorn into a daily driver. The 2470 that's attached to it is rated for a 500hz crossover. I had radian aluminum diaphragms in there, and it was good to about 15khz iirc.

I built those almost ten years ago, and with the advent of better software, I could probably reduce the footprint by about half. But it's still going to be B-I-G; this is not a project for subcompact 


As far as the tweeters up top, I think that's fairly straightforward. The main thing that 'gives away' the location of a tweeter is early reflections and diffraction. In addition, our sensitivity to that top octave is poor, so you have a lot more leeway at 10khz than at 1khz or 2khz. (Due to the Fletcher Munson curves.)

The ideal tweeter would have very very high power handling, to keep up with the compression drivers. You'd want it in a non-diffractive enclosure, like a sphere, so diffraction doesn't 'give away' it's location. Most of your perception of width is going to be dictated by the location of the compression driver and the midrange, so you have a lot of flexibility in where to put it.

Long story short, I'm picturing something like this:

1) midrange or midbass in the doors or in the kicks, or maybe even in the rear quarter panels
2) big, big compression drivers under the dash in custom horns. (All of the existing horns are too small for a 500hz crossover.)
3) a small neo tweeter with a big voicecoil. Something that can put out at least 115dB. It might even be a compression driver like the BMS 4540. Note that with a 10khz crossover, you barely need any horn at all, because the wavelengths are so small.


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## thehatedguy (May 4, 2007)

The B&C DE5 and DE7s are much smaller than the BMS pictured and would be a great tweeter in a very shallow waveguide.


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## chevbowtie22 (Nov 23, 2008)

This all kind of spawned from reading about old installs. Especially the one regarding the blazer from a different thread. My stage height isn't exactly the best but I honestly think its my 8's in the doors that is bringing it down. My fiancé has a set of Focal 30th anniversary components in her factory locations in her 2011 Nissan Altima coupe. Its amazing what tweeters up top on the dash can do. Then again she is also running an MS8 too. Lol


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## quality_sound (Dec 25, 2005)

You don't NEED tweeters up top to get stage height. I know plenty if people with kicks that stage just fine. 


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## Broshi (Jun 9, 2012)

I have decent imaging with my current setup (horns being coupled with bottom of dash and mids in OEM location), but I would probably need kicks and deeper/wider horn mounting for better imaging. The horn mounting will be HARD to pull off due to a shallow footwell, but the kicks will be impossible because, well, 10s. Aiming with pods are a MAYBE, but I reckon a midrange in the a-pillar will help imaging TREMENDOUSLY.


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## thehatedguy (May 4, 2007)

As long as you keep the 10s below beaming, then aiming won't matter.

The thing with tweeters and horns is this IMO, because of how high you are talking about crossing them over, getting them integrated might pose a problem. Dr. Geddes says it would mess up the polar response, and Tom Danley says you need to have you speakers spaced within a 1/4 wavelength of each other for them to sum as a single source. 

Adding them might, might give you more air on the treble because you have increased the dispersion pattern up high as with the conventional horns (and speakers in general), it really narrows from beaming. And you might have some pattern flip going on up that high (though I'm not up on what/how that sounds)..but it makes sense that the treble's dispersion pattern would change because of that. And different horn profiles beam the treble more than others.


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## roduk (Sep 19, 2008)

I have a set of Veritas running B&C DE250's, these sound great, but I also have a set of Infinity Emits sat on the shelf gathering dust… thinking aloud, is there a way/point of mounting the tweeter 'inside' the horn throat somehow to compliment it from 12k up??


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## Patrick Bateman (Sep 11, 2006)

roduk said:


> I have a set of Veritas running B&C DE250's, these sound great, but I also have a set of Infinity Emits sat on the shelf gathering dust… thinking aloud, is there a way/point of mounting the tweeter 'inside' the horn throat somehow to compliment it from 12k up??


There's a 'zone' in a horn, from the diaphragm to the exit of the compression driver, where aiming will make a difference.










In this pic, you can see that my compressin driver isn't firing straight down the throat; it's tilted UP by about 20 degrees.

But this will only have an impact on a narrow bandwidth, because the throat of the compression driver basically acts like a waveguide for the first inch or two. So the directivity for the first couple inches is dictated by the compression driver itself, not the horn it's attached to.

This effect is pretty narrow in bandwidth; on a 1" compression driver it only impacts about 13,500khz to 20khz, or less than one octave. This is because the sound above 13,500khz is dictated by the compression driver, not the horn.

Below 13,500 the horn takes over, and if you want to change the angle of the output of the horn you'll have to physically modify the horn.

Hope that makes sense. Basically you can picture a horn as a series of segments, each one responsible for a fraction of the bandwidth. (IE, the first 1-2 inches is responsible for an octave, and then the next 1-2 inches are responsible for the octave below the last, and on and on until infinity.)


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## Datsubishi (Jan 9, 2012)

chevbowtie22 said:


> I've been doing quite of bit of reading on old school horn installs and I've seen quite few with dash tweeters. I guess I'm a bit curious of this. I'm currently running CD1 Pros in my setup and I don't *need* tweeters on the dash but I'm always open for trying something new. Especially considering I have 2 channels not being used on my amplifiers.
> 
> My questions are for the sake of experimenting what would be recommended for tweeters? Metal or soft dome? Maybe crossed over at around 12,000hz with a 6db slope? Like I said its mainly for an experiment.





chevbowtie22 said:


> This all kind of spawned from reading about old installs. Especially the one regarding the blazer from a different thread. My stage height isn't exactly the best but I honestly think its my 8's in the doors that is bringing it down. My fiancé has a set of Focal 30th anniversary components in her factory locations in her 2011 Nissan Altima coupe. Its amazing what tweeters up top on the dash can do. Then again she is also running an MS8 too. Lol


Have you looked into the CDT upstage kit? I'm not saying its the be all and end all of stage height enhancing, but I thought it was an interesting concept and have thought about it myself. It comes with its own crossovers so you wouldn't necessarily need to use your other two amp channels. Search for CDT upstage on this site, or even just google it, and see what opinions and reviews come up. 

On the other hand, there are decent write ups on specific crossover points they use and tweeter style right on their website. You could copy their idea and see how it works out for you. I'm sure there's some black magic built into their crossovers, but with some time and tuning you could end up with a decent effect. 

Definitely try the tweeters mounted in spheres to reduce diffraction as well. I tried it and the sound was definitely harder to pinpoint. All I used was some small foam craft balls, a hole saw, and a flat sheet of sandpaper to create a very easy functional product.


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## edouble101 (Dec 9, 2010)

How many of you guys that are having imaging/width/height using HLCD's have properly mounted them? I am not referring to just having them mounted securely under the dash. Are they height balanced? Is the parallel alignment of the throat angle near the center line of your ears?


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## Mic10is (Aug 20, 2007)

MANY old Skool horn installs used Tweeter(s) simply for RTA purposes. Consideration has to be given that Competition used to be scored on SQ,Install, RTA and SPL.
Many compression drivers start rolling off quickly above 12khz. adding a Tweeter, which was wired in series or parallel with the horn on a switch , added the ability to put all the dots on the screen and score better in RTA.


Simple experiment to check where the height issues are originating. Turn off sets of drivers and listen.
Shut off the mids and listen to the horns by themselves. where is the stage height?
turn off the horns and listen to the mids themselves...where is the stage height?

typically it is midrange and lower frequencies that pull the stage height down, not higher frequencies which horns will typically play.


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## thehatedguy (May 4, 2007)

Phase and irregular FR will pull the stage down and diffuse imaging.


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## nadams5755 (Jun 8, 2012)

i found that having the horn levels too high pulled the image down, my ears would be drawn right to them.

there's a bit of rainbow with my midbasses in the doors but it's tolerable given the amount of effort i want to put into this.


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## chevbowtie22 (Nov 23, 2008)

Wow this thread took off. 



edouble101 said:


> How many of you guys that are having imaging/width/height using HLCD's have properly mounted them? I am not referring to just having them mounted securely under the dash. Are they height balanced? Is the parallel alignment of the throat angle near the center line of your ears?


Mine are mounted level and flush to the dash. In fact I even have a strip of tape fully sealing the mouth to the underside of the dash.



Mic10is said:


> Simple experiment to check where the height issues are originating. Turn off sets of drivers and listen.
> Shut off the mids and listen to the horns by themselves. where is the stage height?
> turn off the horns and listen to the mids themselves...where is the stage height?
> 
> typically it is midrange and lower frequencies that pull the stage height down, not higher frequencies which horns will typically play.


The majority of the horn frequencies are at about mid way up the dash. Some of the higher frequencies are up on the dash BUT I have noticed this fluctuates greatly based on what I'm listening too. If shut off the horns the 8's are VERY easily localized low. In fact with the horns on some of the male vocals still stay low.



nadams5755 said:


> i found that having the horn levels too high pulled the image down, my ears would be drawn right to them.
> 
> there's a bit of rainbow with my midbasses in the doors but it's tolerable given the amount of effort i want to put into this.


I do need to drop the horns down just a bit. The issue I'm running into personally is if I drop the horns down a bit in output my 8's become even more localized. I'm sure it's an equal issue but I'm still trying to nail it down. It's a never ending cycle of tuning. Lol.


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## thehatedguy (May 4, 2007)

Phase, FR, and time alignment will get you there. Worry about the first 2 of those first.


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## Eric Stevens (Dec 29, 2007)

OK here is the steps to getting stage height as high as possible. I would suggest getting it as good as you can without any processing and then fine tune with whatever processing you have available to you. This is based upon a two seat set up and would vary a little for a single seat set up.

Set crossovers for midbass to horn according the horn and driver combination. I prefer steep slopes of 24dB/oct or steeper in most cases.

Set gains level of midbass first since they are the weakest link in the system, then adjust the level of the horns to where it is on the bright side still or if using an RTA where the top end (>10Khz) is equal to the output from the midbass.

Do the following from the drivers side seat.

Start with everything in electrically correct polarity and all processing off and set to normal phase and use the in phase and out of phase track on the IASCA CD track #3. Listen to the horns with the midbass shut off and see if it sounds more focused and centered in phase or out, if it sounds more focused and centered out of phase, reverse the right horns polarity at the amplifier or on the processor if available. If its best in phase leave it as is. Next do the same with the midbass with the horns off. Do any reversing of polarity on the right side if needed.

Then play the horns and midbass together and listen to track 3 again and make sure it sounds more focused and centered in phase than out of phase. Then go to track 11 on the IASCA CD and listen to height of anouncers on left right and center. If high leave it as is, if low reverse the polarity of both horns at the same time. In many cases you will want to try it both ways until you settle on which way the stage is at its highest.

After this is done if you have signal delays in the your processor for each speaker you can do further alignment of the horn to midbass. To do this you would sit in the drivers seat blalance all the way left so sound is only coming from the left speakers and listen to the announcer on the IASCA CD or other spoken voice and delay the midbass in small increments until the voice is as high as possible with just the left side playing, copy this delay setting to the right side midbass.

Next would be to do separate left right EQ if avialable or just EQ both channels together.

Eric


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## Horsemanwill (Jun 1, 2008)

eric,

have you done that write up yet i keep tellin you to do?


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## quality_sound (Dec 25, 2005)

So no T/A to balance the left and right sides?


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## edouble101 (Dec 9, 2010)

Here is a video to show part of the installation requirements.

Horn install #2 - YouTube


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## Eric Stevens (Dec 29, 2007)

quality_sound said:


> So no T/A to balance the left and right sides?


For two seat which is the outlined above I might delay the signal on the left side between .05 and .35 milliseconds to focus up the center if needed. I am essentially using the delay as finite phase adjustment.

For single seat I do many things the same but when I get to setting the delays I vary my technique for setting the delays for maximum height and depth etc.

For best results you need to do separate left right EQ also in single or two seat systems. 

Eric


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## quality_sound (Dec 25, 2005)

I remember the EQ method you taught Terry (which works very well, BTW) way back in the 90s. The TA part threw me until you reminded me it was for two seat. 

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