# Super tweeter with HLCD



## GONZO151 (Jun 29, 2013)

I picked up a pair of prv audio super tweeters as part of car audio trade I made. I have been wondering what they would sound like paired with My ES horns ,I have read that they could add sparkle to the upper frequency
So if anyone could share with me the correct way to wire them in with my horns . I have the pro drivers on the horns 8ohms the super tweeter are 8 ohms 105 db spl 3-5 kHz they have 2.2 uF cap already so share what and how you would wire them.my horn amp can handle the ohm load of the horn and super tweeter wired in parallel ,My starting point for my HU xover point(pioneer prs99)

Sub- 25hz-63hz
Midbass-63hz-1k
ES horns 1k- up

I'm just looking for the ez way to connect the super tweeter being that I'm just testing them but I don't want to hurt my others equipment I read a post were a member used a 2.2uf cap with a 4.7 resistor but I couldnt get from the post what the xover point would be with that combination or why the resistor was used I do understand that I could run them on there own amp but I'm not married to the ideal on running the super tweeters in my final set up


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## SkizeR (Apr 19, 2011)

midbass crossed at 10khz?


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## rockin (Sep 13, 2012)

Don't know about MB crossed at 10K, but... get on an RTA and see where the horns roll off on top. From there its pretty easy, HP / your super tweets where they intersect w/ horns at -3 db. Did mine passively very happy w / results.


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## GONZO151 (Jun 29, 2013)

Made correction on my post it's. 63-1k mid bass


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## minbari (Mar 3, 2011)

unless you have poor treble response, I dont see why you would want one. I have the entry level horns from ES and they have more than enough treble. people think I have tweeters hidden in the dash or the vents or something.

just EQ them till they sound right.


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## Canopy (Sep 16, 2013)

minbari said:


> unless you have poor treble response, I dont see why you would want one. I have the entry level horns from ES and they have more than enough treble. people think I have tweeters hidden in the dash or the vents or something.
> 
> just EQ them till they sound right.


+1 I have ES horns and after a little eq up top I have no desire for a super tweeter.


Little off topic but what midbass are you running OP, that goes down to 63hz? Just curious cause my 8g40 drops like a rock around 125hz and I find I'm bringing my sub up too much to fill the gap.

*EDIT Found out this was due to my measurement error.


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## Eric Stevens (Dec 29, 2007)

Canopy said:


> +1 I have ES horns and after a little eq up top I have no desire for a super tweeter.
> 
> 
> Little off topic but what midbass are you running OP, that goes down to 63hz? Just curious cause my 8g40 drops like a rock around 125hz and I find I'm bringing my sub up too much to fill the gap.



8g40 Beyma should do well to 80 Hz so there could be issues with install or tuning. 

Start a new thread and post some pictures and details of the mid bass install and I will help you get it better.

eric


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## Canopy (Sep 16, 2013)

Eric Stevens said:


> 8g40 Beyma should do well to 80 Hz so there could be issues with install or tuning.
> 
> Start a new thread and post some pictures and details of the mid bass install and I will help you get it better.
> 
> eric


Eric,

I will take some pics after work and post them up along with a graph. Thanks.

*EDIT found this was due to measurement error.


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## Patrick Bateman (Sep 11, 2006)

GONZO151 said:


> I picked up a pair of prv audio super tweeters as part of car audio trade I made. I have been wondering what they would sound like paired with My ES horns ,I have read that they could add sparkle to the upper frequency
> So if anyone could share with me the correct way to wire them in with my horns . I have the pro drivers on the horns 8ohms the super tweeter are 8 ohms 105 db spl 3-5 kHz they have 2.2 uF cap already so share what and how you would wire them.my horn amp can handle the ohm load of the horn and super tweeter wired in parallel ,My starting point for my HU xover point(pioneer prs99)
> 
> Sub- 25hz-63hz
> ...


There's a couple of options here:

1) If you use the 2.2uf cap by itself, you'll be rolling off the super tweeter at 9khz. So basically it's going to be adding some 'air' in the octave from 10khz to 20khz.
2) If you think it's too loud, then put a resistor between the cap and the amp. For instance, a 10 ohm resistor will drop the level by seven decibels. You can get that resistor at Radio Shack for $2.

Personally, I would probably put the resistor between the cap and the compression driver. Doing that makes the crossover work better, because it reduces the effect of the compression drivers impedance peak.

If you go *that* route, you have to drop the cap to a lower value. One microfarad, to be exact.

So in this scenario, it would look like this:

amp -> 1mfd cap -> 10ohm resistor -> positive terminal of your supertweeter


If you don't have any 1mfd caps laying around, then just do it like this:

amp -> 10ohm resistor -> 2mfd cap -> positive terminal of your supertweeter



Note that you can use insanely high frequencies for compression drivers. I personally cross them over at 20khz or so. The reason that this works is that compression drivers have a response that looks like this:










Due to the high frequency droop of a compression driver, when you combine the two filters you end up with flat response. For instance, here's what happens when you roll it off at 20khz:

1) At 20khz the filter is reducing output by 3dB. So the output at 20khz goes from -18dB to -21dB.
2) At 10khz (one octave lower) the filter is reducing output by 9dB. So the output at 10khz goes from 7dB to -2dB. (reduced by nine dB.)
3) At 5khz (two octaves lower) the filter is reducing output by 15dB. So the output at 5khz goes from 14dB to -1dB. (reduced by fifteen dB.)
4) At 2.5khz (three octaves lower) the filter is reducing output by 22dB. So the output at 2.5khz goes from 17dB to -5db. (reduced by 22dB) 

Hope that makes sense. The combination of the cap and the compression drivers natural response yields a flat response. So if you have enough power, there's a lot of good reasons to set the filter up really really high in frequency.


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## subwoofery (Nov 9, 2008)

Always wondered... With conventional drivers, I often hear that the best way to cross a mid to a tweeter is to match the dispersion caracteristics @ the Xover. 
With a horn, which controls dispersion, do you want a super tweeter with narrow directivity or the opposite. 

I do know that the higher you go, the less the horn controls dispersion over the compression driver. Correct? If yes, then horns have wider dispersion above 10kHz than let's say @ 2kHz. 

Kelvin


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## Eric Stevens (Dec 29, 2007)

Horns are Subject to the same laws of physics and beam more at higher frequency as well. The horn to mid bass crossover at say 800 Hz is easy since they are both in their power response frequency range. It gets more difficult with conventional tweeter because you are up higher where the mid is beaming.

Eric


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## Patrick Bateman (Sep 11, 2006)

subwoofery said:


> Always wondered... With conventional drivers, I often hear that the best way to cross a mid to a tweeter is to match the dispersion caracteristics @ the Xover.
> With a horn, which controls dispersion, do you want a super tweeter with narrow directivity or the opposite.
> 
> I do know that the higher you go, the less the horn controls dispersion over the compression driver. Correct? If yes, then horns have wider dispersion above 10kHz than let's say @ 2kHz.
> ...


Directivity control is simply dictated by size.
A 10" waveguide will start to beam at 1350hz.
A 10" woofer will start to beam at 1350hz.

At high frequencies a waveguide is omnipolar, but that's simply because the throat is straight. For instance, a 1" compression driver will start to go omni at 13,500hz, because a 1" wavelength is 13,500hz.

So a 10" waveguide with a 1" throat will control directivity from 1350hz (10") to 13500hz (1")


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## GONZO151 (Jun 29, 2013)

I wanted to test my ES horn with my ipad RTA app so broke out my smd signal gen. And my 
Behringer ECM 8000 mic via my IRig(48v pre amp) to see how high my horns would play ,now this was just a simple bench test using a signal gen . I placed the horns about 12" from the horn mouth and the signal gen in Hi setting starts at 515 hz so I started there and worked my way up to the limit on the signal gen. Being 22.5 kHz .well the horn played up to 19.4 kHz @ 64 db then dropped off the screen ,on the lower end 505 hz @79 db then it curved down to 200 hz @32 db. I stopped there I didn't want to chance damaging 
the driver . So this simple test helped clear up for me that the horn dose play up high and doesn't just become in audible 
So I tested the super tweeters 19.28 kHz @58 is we're it dropped and being that my rta only go's to 20 kHz I don't know what the limits of the horns or tweeter are beyond that
So I leaned the horns played as high as the super tweeter did ,but louder .this my be do to the 2-3 db difference in sensitivity .from my listening test nothing magical happened 
When I wired them in with the horn LoL ..it just added very bright top end 
So I'm not going to install them after all it's not because the super tweeters sound crappy with the horns but it didn't make that much of a difference to me in to added them in . One member posted above that if I eq the upper feq. That would help my horns well
From what I learned from the rta readings is that all the horns would need to get 
A little more sparkle is some top end eq ing , Im sure other people may have better super tweeters than my prv and like what they sound like in their set up I just don't think in my case It adds anything that I couldn't already get with my dsp/eq so I'll pack them away and use on another install (not a scientific test 
It's just my own research and listen pleasure )


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## Patrick Bateman (Sep 11, 2006)

If you repeat that test with your microphone about three feet above the horn mouth, you'll find that the treble is disappearing with a quickness.

Having said that, it's easy to "add it back" with EQ, which is what I do. While adding ten or fifteen dB of EQ at 1khz is a really bad idea, at 15khz it's no big deal because excursion is basically nil at high frequency and we've got efficiency to burn.


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## GONZO151 (Jun 29, 2013)

Thanks for the info I wasn't sure what the ideal distance would be so I just use 12"


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## Eric Stevens (Dec 29, 2007)

The horns will obviously measure best right at the horn mouth but they don't lose that much on the top at the listening position. The new pro and ultra drivers have quite good top end not beginning to roll off until very high in frequency. 

Look for a response curve posted by Big Red in the HLCD section for the response on the Ultras.

Eric


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## Patrick Bateman (Sep 11, 2006)

Eric Stevens said:


> The horns will obviously measure best right at the horn mouth but they don't lose that much on the top at the listening position. The new pro and ultra drivers have quite good top end not beginning to roll off until very high in frequency.
> 
> Look for a response curve posted by Big Red in the HLCD section for the response on the Ultras.
> 
> Eric


Oh I know, hope it didn't come off as harsh, I just wanted to make the point that the horns should be measured OFF axis not on.

Measuring horns is really an art; it took me about five years to come up with a method that comes up with good results. IMHO, all of my high frequency measurements from before 2008 or so are semi-worthless because I was working on a set of false assumptions.


It boggles my mind that people have five hundred page discussions of what the best amplifier is, yet loudspeaker measurement is barely discussed.


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## Eric Stevens (Dec 29, 2007)

No offense or harhness taken. 



Patrick Bateman said:


> It boggles my mind that people have five hundred page discussions of what the best amplifier is, yet loudspeaker measurement is barely discussed.


Getting good at speaker measurements takes experience and knowledge. 

Might have something to do with most consumers and industry professionals speakers are more of an art than amplifiers where people think the performance can be easily or even solely expressed with numbers derived from technical measurements.


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## BigRed (Aug 12, 2007)

I think Todd Luliak said it best. A good sounding car is a careful mix of art and science.


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## rockin (Sep 13, 2012)

GONZO151 said:


> I placed the horns about 12" from the horn mouth


?? 

Install everything where it will be installed permanently, place the RTA mike where your head will be, play some pink noise and gather some data. 
Why would you ever measure anything other than exactly WHERE it will be installed (esp. horns) and a mike anywhere other than where your ears will be ?

I love theory, it's like boresighting a rifle. It'll get you on the target, but then you need to measure and tune to hit the bullseye. There are too many variables IMO that cannot be accounted for by theory in car audio. When I boosted 14k -20k on my horns it sounded like ASS reheated. Your mileage may vary. As you point out this is only about satisfying your personal taste (which is always nice) We have different horns installed in different vehicles w/ different processors, etc. u get the idea.


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## Patrick Bateman (Sep 11, 2006)

rockin said:


> ??
> 
> Install everything where it will be installed permanently, place the RTA mike where your head will be, play some pink noise and gather some data.
> Why would you ever measure anything other than exactly WHERE it will be installed (esp. horns) and a mike anywhere other than where your ears will be ?
> ...












^^ For the same reason that guys like Paul Spencer measure speakers this way

In order to get a good clean measurement, you need about five to ten cycles to hit the mic without a reflection.

So lets do the math:

If you wanted to get ten cycles at your mic, and you wanted to measure down to 100hz, then you need to eliminate all reflections within 112.5 feet. No, seriously, a hundred and twelve feet.

(speed of sound / 100hz) * 10 cycles =
(13500 cycles per second / 100hz) * 10 =
1,350 inches = 
112.5 ft​
Now, obviously, that's crazy talk. It just can't be done.

So let's knock our criteria down to five cycles, and set a lower limit of 250hz:

(13,500 / 250hz) * 5 =
270" =
22.5​
If you have a big yard, and a big ladder, you can probably get a clean measurement down to 500hz, maybe 250hz.


I'm not 100% opposed to doing measurements in the car, but I see them as "icing on the cake." I make my decision on whether a waveguide or horn will work using the semi anechoic measurements first. *Some horns just work better than others, and semi anechoic measurements will show you that.* If you check out my 'edge of no control' thread at diyaudio, you'll see what I mean. I measured the same compression driver on four different horn profiles, and the JBL progressive transition waveguide won. As a bonus, it was also the second cheapest! Gotta love that combination. An RTA is going to 'blur' out all the things that tell you whether a waveguide or horn is working well. Easiest way to tell if a horn sucks is to look at the impulse response, not the frequency response. (Frequency response is actually derived from the frequency response, so technically you *could* see it in the FR, but it's easier to see in the impulse response.)



Here's an anecdotal example of how measuring anechoically can save you a lot of time and work:

I began making my own horns in the late 90s. I would build one or two horns a year. The first one that really worked well was the one documented in the thread titled "twelve inch woofers in my dash." That was in 2006. *So we're talking about eight years of trial and effort.* That was literally thirty percent of my lifetime dedicated to trial and error.

In the past three months, I have tried about five different horns for my Mazda6. I was able to determine whether the horn was working well in about one week each. Basically mount the compression driver, take it outside, measure it semi-anechoically, EQ it flat, listen to it.

Here's the kicker:

*The JBL PT waveguide worked the best. I had it sitting on my bench, and noticed something funny: it's virtually the same shape as the waveguide I built in 2006.*

So I'd stumbled onto a very very good waveguide shape eight years ago, but it took eight years of trial and effort to get there. A mic and semi anechoic measurements can get you there in weeks not years.









Here's a pic of the well regarded QSC waveguide, my mold from 2006 in the middle, and a male mold I made based on using the QSC as a female mold. *See the similarity?* The one in the center wasn't copied from QSC, we both just zeroed in on the same shape coincidentally.









Here's a LeCleach mold I made. *See how it's much deeper?* These deep horns were the norm in car audio in the 90s, but they just don't work well off-axis. I've read stories about cars that used very deep horns in an effort to lower the frequency of the horn flare. I've also heard the cars didn't sound good. See a trend here? wide and shallow sounds good off axis, deep and narrow doesn't.

Another great thing about this process is that you develop a 'short hand' for what does and DOESN'T work in a car:

1) shallow horns work better than deep
2) wide angles work better than narrow
3) even a tiny amount of vibration will cause the horn to have peaks and dips across the entire bandwidth

That last one is another example of something you'll NEVER see with an RTA. Five years ago I literally had NO idea that my horns and waveguides need to be bulletproof. You'll notice that most of the ones I build now are wood / fiberglass composites. That's why I do that : it improves the frequency response. (And the impulse response.)



Net effect is quite magical, the quality of the horns I'm making now is leaps and bounds beyond what I was doing in 2009. And what I was doing in 2009 wasn't too shabby either.

I really want to give all this information away btw, I don't compete, I hope that my 'research' helps raise the bar when it comes to putting horns in cars.


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## rockin (Sep 13, 2012)

and I think all that research is absolutely crazy over the top. I've followed your work for a while, ever since you put the foam inserts in the horn bodies. The fact that someone is that obsessed with the engineering and performance of HLCDs is daunting. The fact that you share the results of your research with this community for free is awesome, IMO. I appreciate theory now more than ever. It is useful to save money and time and get close on the first install. But I still say the final step, the "icing on the cake" is critically important. Whatever the theoretical performance predicts, the final results don't lie, right?


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## Patrick Bateman (Sep 11, 2006)

rockin said:


> and I think all that research is absolutely crazy over the top. I've followed your work for a while, ever since you put the foam inserts in the horn bodies. The fact that someone is that obsessed with the engineering and performance of HLCDs is daunting. The fact that you share the results of your research with this community for free is awesome, IMO. I appreciate theory now more than ever. It is useful to save money and time and get close on the first install. But I still say the final step, the "icing on the cake" is critically important. Whatever the theoretical performance predicts, the final results don't lie, right?


The more I measure, and the more I listen, and the more I build, the more I think that what happens in the first millisecond is what's important.


















^^ Here's the impulse response from a B&W 801.
*See how the sound has a peak, and then it slowly decays?*
And in that decay, there's some wiggles?
That's good performance, and in a car this would sound really good.

















^^ Here's the impulse response from a Dunlavy SC-IV
*See how the sound has a peak, then just 'fades to black' inside of one millisecond?*

That's exceptional performance. Probably not even possible to do this in a car, but I'd like to get close.

When you listen to a system with this kind of impulse response, elements in the music just fade into an inky black background in milliseconds. When a piano is played, the notes decay cleanly and quickly. When someone sings, their words are intelligible and articulate.

An RTA can't pick this up; you really have to look at the impulse response, step response, etc.


Also, once you start chasing this kind of performance, you start to spend a lot of time obsessing over phase, not frequency response. (Though both are important.) The B&W has great frequency response, but the impulse response of the Dunlavy fades to black quicker because of the type of crossover filter used.


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