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Discussion Starter #1
Hi All,

I posted a week+ ago about the sibiliance in the system for my Honda Accord. At the time, I had Infinity 6030cs components just installed in the front, Infinity Kappas in the back, and a 75rms watt amp powering it all. Wanting desperately to keep the factory headunit, so that's still there.

After checking amp settings and wiring, the sibilance was still harsh, and I got a great tip on here to try the DLS T25 tweeters which are notoriously laidback (not harsh like Infinity, apparently). Well, I just got them installed and the sounds is STILL PRODUCING SIBILANCE. S's and T's pierce through every song. These tweeters are slightly better, but not enough.

I am going to admit something so please don't bite my head off: I had a local, reputable shop do the installation so I don't know much at all about car audio and haven't been doing any of the work myself. All I know is that I can't stand the sibilance anymore and don't know what to do about it. Is it the headunit? The acoustics? Is there a break-in period for tweeters? Can it be solved with an EQ? Any ideas? Sorry but this has been a money pit.

Thanks,
Joe
 

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Pictures of how they're installed?

EQ may or may not fix it depending on whether the problem is a peak, overall level matching issues, phase/deflection issues, etc...
 

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What is the crossover point on the tweeters? I assume you are running a passive crossover. Switching out the tweeters alone with a passive crossover might screw up the actual crossover point you are getting if the tweeter isn't the same ohm load. No telling where the crossover point is when that crossover isn't built for that specific tweeter.
Your new DLS tweeter could be more sensitive and creating an imballance. Attenuation could be the cure (resistor in series?).

I've had problems with sibilance and have my tweeters in the door as well. I was able to get rid of most of it with time alignment and EQ but also by raising the crossover point. I went to an active setup to cure this problem.
I'm still not sure what did help the most as I've tried several things.
There are still a few recordings where I hear it, but I can hear it on my headphones (German Maestro) as well on those recordings.
One problem I found was that I sort of trained myself to hear those SSS and T's after a while. It was like I was only hearing S and T sounds and I was able to hear it on home audio and at other places as well. The only difference was that I would forget about it after a while at those other places but always remembered to listen for it in the car :laugh:.
I tried wrapping the tweeters with the foam ear pads from a cheap head set and that seemed to help out a bit. That's easy to try out.
I assume the DLS are 25mm tweeters. I think the bigger the tweeter, less chance of them beeing harsh. I have 28mm Hertz Space One tweeters, most call them laid back, the reason that I got them, but I know they can produce sibilance in my door position. Before that I had Pioneer tweeters TS-e170ci (TS-D720) and in hind sight, they produced less sibilance but the Hertz sounded way more open so I focussed on curing those. At one point I noticed I was enjoying my music and not focussed on hearing the SSS and T sounds, that's when I knew it was possible to cure it (or cure me ;)).
So chances are most tweeters will sound harsh in that position. Have you tried wiring one or both out of phase (reverse + and -)? Maybe an L-pad could be used if your crossover does not have different level positions like 0 db, -3 db etc.
Try and unhook the tweeters for a drive and listen only to the woofers. Who knows, they might be part of the problem. It won't sound pretty but it will give you an idea of the sound they produce up high. Do the same by unhooking the woofers and only listening to the tweeters for a day/drive.
You'll be surpriced to hear them play by themselves. That's when I realised it could be a phase problem between woofer/tweeter. My HU has TA so I started playing with it some more and I still think the solution came from the Time alignment.

Here's my tweeter door position:


I'm very happy with my setup now, so don't give in right away. Just try different things, like trebble control on the stock HU etc.
I tried everything from changing out amplifiers and reducing diffraction, tweeter aiming but in the end I suspect part of the problem was my focus on hearing the sibilance. Now I'm just enjoying the music again. It is very difficult not to focus on the sibilance after a while, that's why I suggest listening to only the tweeters / only the woofers to hear what they actually play.
 

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As you're running off the factory HU and they have crappy "EQs" and often have built in EQ to take account of sh!t factory speakers I would try running the amp straight off an ipod and see if the sibilance is still there

Cut 4-6Khz, that's where you'll get sibilance:

Interactive Frequency Chart - Independent Recording Network

It's unlikely your crossovers would be crossing the tweeter higher than this, normally more around 2-3.5KHz, check and see if the crossover LPF's the mid-if not your sibilance could be coming from the mid and not your tweeter.

As you're running off the factory HU and they have crappy "EQs" and often have built in EQ to take account of sh!t factory speakers I would try running the amp straight off an ipod and see if the sibilance is still there-if it's gone it's your source unit's EQ if not then check the crossover.
 

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Discussion Starter #9
Yes, I did make sure that it is set to 0db rather than 3db+. I am not sure about the crossover points on the tweeters since someone else did the install, unfortunately.

How would I go about hooking my iPod up as the source to my amp? Sorry, really remedial DIYer here.
 

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Also make sure the tweeters are not clipping.

Do you know what clipping sounds like?
 

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Discussion Starter #11
These are brand-new tweeters and they are sibilant event at low volumes, and my previous tweeters did the same thing, so I don't think it's clipping.
 

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These are brand-new tweeters and they are sibilant event at low volumes, and my previous tweeters did the same thing, so I don't think it's clipping.
Clipping can happen either from the amp or to the amp, so new tweeters may not rule it out yet.

If your signal to the amp from the headunit is too loud, you get clipping before the amp has even touched the signal, where if the amp gains are set to high you get clipping from the amp itself.

How are you getting a signal from the stock headunit? If the shop used a high level converter, it may be set too high so try to trim it back a bit a see if that helps. If the high level converter they used does not have any adjustments, then you should have them make sure it matches your amplifier input range or replace it with one that can be adjusted.

Your amp should have an aux input which you can plug your mp3 player directly into so you can rule out the headunit/converter as the source of the problem.
 

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Clipping can happen either from the amp or to the amp, so new tweeters may not rule it out yet.

If your signal to the amp from the headunit is too loud, you get clipping before the amp has even touched the signal, where if the amp gains are set to high you get clipping from the amp itself.

How are you getting a signal from the stock headunit? If the shop used a high level converter, it may be set too high so try to trim it back a bit a see if that helps. If the high level converter they used does not have any adjustments, then you should have them make sure it matches your amplifier input range or replace it with one that can be adjusted.

Your amp should have an aux input which you can plug your mp3 player directly into so you can rule out the headunit/converter as the source of the problem.
I agree with the above.

Here is a great diagnostics tool:

Get a pair of walkman-style headphones. The kind you get for free on an airplane work great.

Cut off the end-plug, and solder up some Male RCA jacks. Also buy some double-female ended RCA adapters.

Put the headphones on, and plug into your audio signal BEFORE it goes to the amps.

IE, we are creating a low-level listening device.

You can also use this:

RadioShack® Mini Audio Amplifier - RadioShack.com

THAT little beauty will tell you if you have clipping or not.

Download a 1 KHz test tone and burn it to a CD and play it. If you hear distortion, you are clipping!
 

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Discussion Starter #14
So I plugged in a headphone to dual-RCA wire into my amp and played the iPod directly in to the front channel, and when I switched the amp into two channel mode, there was no sibilance at all. When I left it in four-channel, there was mild sibilance but less than when the amp is connected to the LOC and headunit. Is there a certain significance to that??? Thanks, all!
 

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Is it possible you're getting low frequency material to the tweeters? Mine got very harsh when this happened to me. They never blew but they sounded terrible.

It sounds like they're running on the Infinty's passives?
 

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Discussion Starter #17
When you switched it into two channel mode, how did you have everything wired?
I had the red/white RCA input ends connected into the front channel of my amp, and on the other end of the wire was a single headphone end that was plugged directly into my iPod. In two channel mode on my amp, everything sounded more unclear than coming from my headunit, but no sibilance at any volume!

I then tried switching to four channel and there was minor sibilance but didn't seem as much as when the signal was coming from the headunit/LOC.
 

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Discussion Starter #18
Is it possible you're getting low frequency material to the tweeters? Mine got very harsh when this happened to me. They never blew but they sounded terrible.

It sounds like they're running on the Infinty's passives?
Yes, I am running on the Infinity passives but I think everything is crossed over correctly because it is a really simple crossover with few options. Could the crossover be to blame at all? It isn't only that it is sibilant, but there does sound like some minor distortion, especially with female vocals, coming from the tweeters. It sounds sibilant on the back deck Kappa 6X9's tweeters too, however.
 

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I'm wondering if the tweeters are out of phase? or maybee they NEED to be out of phase, some times this does the trick, but not always.

This might sound strange, but you can also try adding a ferrite choke to the line just before the tweeter, this may cut them enough to take care of your issue.
Ferrite Core 1/4" Cord Noise Suppressor 110-450
 

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Yes, I am running on the Infinity passives but I think everything is crossed over correctly because it is a really simple crossover with few options. Could the crossover be to blame at all? It isn't only that it is sibilant, but there does sound like some minor distortion, especially with female vocals, coming from the tweeters. It sounds sibilant on the back deck Kappa 6X9's tweeters too, however.
I'm not at all educated on passive crossovers but I do believe the impedance of the tweeter has an effect on the crossover point. So if the Infinities had a 2 ohm tweeter and the new tweeter is 4 ohm, it might be causing problem such as too high or low of a crossover point.
 
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