Tweeter hiss noise, is this normal?

[Meruem]

if you hear noise with the head unit off, that doesn't always mean the amp is off.
pull the fuse at the battery for the amp. does the noise persist?

if so, it's not related to your sound system.

i've seen/heard amplifiers that had a whine or a hiss due to internal radiated noise. it's not normal, but it can happen and is usually tied to the switching power supply. hell, i've got a rockford amp on my test bench right now that has a very high frequency whine. you'd never know in the trunk but under a seat it would drive you nuts.

I'll give that a try tomorrow, ty

 

[DARKHART 10+ year member]

Once you pull the fuses and it still persist as kha stated it's not the system, also check under the dash where they ran the main power for the amp through the firewall, if they made the hole too big and didn't properly grommet it then the excessive opening could be just large enough to allow more sound from the engine bay into the cabin. As unlikely as it sounds I have seen it happen and as far as buying the Audison amp goes, I don't think I would spend anymore money with them because it still sounds like you have engine noise once the system is turned on as well.

 

[Meruem]

Once you pull the fuses and it still persist as kha stated it's not the system, also check under the dash where they ran the main power for the amp through the firewall, if they made the hole too big and didn't properly grommet it then the excessive opening could be just large enough to allow more sound from the engine bay into the cabin. As unlikely as it sounds I have seen it happen and as far as buying the Audison amp goes, I don't think I would spend anymore money with them because it still sounds like you have engine noise once the system is turned on as well.

Good idea, ty! Never would have thought of that

 

[Meruem]

I didn't get a chance to perform any maintenance on the car today. It was a busy day at work.

I did notice that I'm getting a lot of https://en.wikipedia.org/wiki/Galvanic_corrosion on my positive battery lead. battery is brand new and purchased 3 months, 12 days ago. Got the battery tested at two car shops. 12volts stable @ idle. ~13.95 volts stable while reveing engine. Both places the battery checked out ok

battery testing shop did not claim it to be an issue and that some cars get corrosion on their positive very easily and some do not hardly ever get corrosion.

Meh.. just drawing at straws

 

[hispls 5,000+ posts]

OP, it's really time you do some troubleshooting to isolate the problem. Trust and believe that any audible noise is unacceptable and you should NOT be paying to make that go away (unless you're buying equipment at walmart).

If the shop is just trying to up-sell you on new equipment RUN away from them. A simple process of elimination should be able to isolate the source of your problems by just pulling wires and listening for noise.

I'd like to say first of all, if your battery terminals are corroding clean those up really good and use either some Vaseline or dielectric grease on them to keep corrosion from returning.

Have you removed the RCA cables from the amp then listened for the noise? Remove at the head unit, remove at the amp. Where is the amp grounded? Have you upgraded the ground from the battery - terminal to the vehicle frame?

This should NOT cost you money to fix. Either the install is bad or you have a faulty piece of equipment that should be warrantied. Buying snake-oil wires is NOT going to fix this.

 

[Meruem]

Have you removed the RCA cables from the amp then listened for the noise? Remove at the head unit, remove at the amp. Where is the amp grounded? Have you upgraded the ground from the battery - terminal to the vehicle frame?

This should NOT cost you money to fix. Either the install is bad or you have a faulty piece of equipment that should be warrantied. Buying snake-oil wires is NOT going to fix this.

I removed all the RCA's form the AMP and the speaker hiss from the tweeters was still there at the same volume level

I'm going to try a new AMP next week (audison sr4) to see if it resolves the issue

I'm not sure where the AMP is grounded. I'll ask.

Also not sure where the battery is ground, i'll try and find out

 

[Meruem]

Here's some pictures of my battery and my negative terminal Negative Terminal - Album on Imgur. I can see 3 cables connected to it. One of them goes straight down and grounds to the chassis. the other two go somewhere I dont know.

I still need to ask the shop where they ground the amp ... likely not near the car battery though since the amp is clear back in the trunk area.

 

[Meruem]

Here's some shots of my engine/battery: 2008 Rav4 Car Battery 20150207 - Album on Imgur

 

[Meruem]

here are some shots of the amp power wire connected to my positive terminal going through my firewall.. best shots i can get.. without tearing everything apart (which i dont know how to do) : Positive Terminal to AMP in engine compartment - Album on Imgur. The power wire is the smaller one with the dark black plastic around it

it looks like they piggybacked another firewall entry. I dont know what that big tube is next to it is. any idea what that could be?

 

[Meruem]

Have you removed the RCA cables from the amp then listened for the noise? Remove at the head unit, remove at the amp. Where is the amp grounded? Have you upgraded the ground from the battery - terminal to the vehicle frame?

So I removed the RCA cables from AMP and the hiss noise remains from the tweeters. So it must be somewhere in this chain: Car Battery -> 100AMP inline fuse -> AMP -> [9wire, stock speaker wire runs, hertz speaker wire, other wires in the car] -> New Hertz Speakers

I had my battery/alternator checked at two places and both checked out my battery was functioning very normally. I'm glad they offer these tests for free

I really starting to think it is the zapco a crappy amp. I'll know for sure next week when I get the audison sr4 installed

 

[Meruem]

Lowend rcas can cause this, but most of the time its the speaker wire used during install.
If the speaker wire is lowend and is near the door window motor or by power wires you will hear a faint hiss noise especially from tweeters.

If it was the rca then it would get louder by engine going faster or when gains are high enough to produce an amplified sound.

If its the same with the gain all the way down 99% time its the speaker wires.

I finally got around to removing my front passenger door to see the wiring. It does look like the wires are near the mirror motor wire. I took some pictures here: Possible Tweeter Hiss Cause From Mirror Motor Wire - Album on Imgur

Do you think this could be the cause, possibly? I'm not so sure because the stock JBL's wires for the components were probably wired in a similar way (i have no clue though), and I didnt have hiss with those stock tweeters.

 

[los33 10+ year member]

I finally got around to removing my front passenger door to see the wiring. It does look like the wires are near the mirror motor wire. I took some pictures here: Possible Tweeter Hiss Cause From Mirror Motor Wire - Album on Imgur
Do you think this could be the cause, possibly? I'm not so sure because the stock JBL's wires for the components were probably wired in a similar way (i have no clue though), and I didnt have hiss with those stock tweeters.

At this moment you are better off testing a new amp before going any further as the window motor can cause hiss, but mainly only when the motor is in use.

 

[Meruem]

At this moment you are better off testing a new amp before going any further as the window motor can cause hiss, but mainly only when the motor is in use.

ya i agree

 

[Meruem]

Got a new amp. Interesting results.

The shop put in a Audison SR - SR 4 to replace the Zapco

They also cleaned up the install a bit, I like it a lot.

You can see the progression as they tried to address the hissing noise

First Install: First Service - Album on Imgur

Second Install: Second Service - Album on Imgur

Third and current Install: New Audison SR4 (Replaced Zapco ST-5X) - Album on Imgur

Results: Hiss is present; however, it can now be made quieter and even eliminated (at listening position) by adjusting the gain on the Audison AMP. Adjusting the gain on my old Zapco did not affect the hiss level at all. With the Zapco, full counter clock gain had the same perceived hiss loudness as full clockwise.

Today when I got my car back, the Audison SR4 was at full gain, so I heard the hiss. The noise level of the hiss was, I'd guess, 20-30% less than the Zapco. Also, the Zapco hiss had little poping noises in the hiss, which the Audison does not. The Audison sounds like pure clean hiss. I'd rather hear clean hiss than inconsistent poppy hiss, if I have to hear it. Though I have to consider, the shop made cable routing changes, and who knows what else, which could have improved things. So the improvements may not be completely amp related

I came home and started doing some testing. These are my observations:

* At 0 volume on the head unit, with any source, the hiss now goes away completely. Previously with the Zapco amp, the hiss was the same loudness when the volume was at 0 or 20, regardless of gain setting

* All sources on the head unit except USB1 and USB2 make a hiss noise with my system, even with nothing plugged in or connected on those sources

* The head unit specs say "Three sets of 5-volt preamp outputs send a high-powered, low-noise signal to your external amps." The Audison SR4 says VRMS (see pictures on third install). I have no idea if VRMS directly corresponds to the preamp volts on the head unit, anyone know? Is VRMS the same as Gain? I figure VRMS and Gain are the same thing since there is no dial labeled "Gain" on the Audison SR4.

* I notice better sound quality from the Audison AMP. Sounds cleaner and clearer. Though: When I lower the VRMS (to reduce the hiss), I have to turn up the head unit volume more, and I can't tell if I'm loosing sound quality. I want to say it sounds better with the gain set to full clockwise, but its hard to tell. Is there a difference in setting the amp to full gain, with a lower head unit volume level versus setting the amp to less gain with a higher head unit volume level?

* At 5 VRMS, I can not hear any hiss at listening position volume 1-24. I start to hear very little his at volume 25+. The hiss gets progressively louder as I increase the head unit volume. Listening to music volume is around the 35's range for this VRMS.

* At 6VRMS, I can hear a low level of hiss at volume 1 which is tolerable. The hiss doesn't start to get louder until about volume 25+

* At 7 through 10VRMS, I can hear a progressively louder hiss from the tweeters at listening position. However, I very much like like how, with this amp, the hiss goes away completely at 0 volume on the head unit

* 10VRMS sounds AMAZING. And the fact that I can just turn the volume to 0 now to eliminate the hiss, is great. Previously with the Zapco, I had to turn off the entire head unit/AMP to eliminate the hiss. This was no good because then I could not receive Bluetooth calls. The hiss at 10VRMS is very noticeable in a quiet environment (like a parking lot or a garage), but when driving the road noise pretty much covers it up unless you are specifically listening for the sound.

* At 10VRMS, and at about 18-21 head unit volume is my sweet spot. At 5VRMS (no hiss), I need to put the head unit around 35 to get the same loudness/clarity. These Hertz speakers seem to really brighten up the louder you play them. I still am trying to determine if 10VRMS @ 18-21 volume sounds the same as 5VRMS @ 35-40 volume. My subjective opinion is that the 10VRMS sounds better.

What do you think is better for sound quality. Setting the head unit high pass filter to off, and setting the amp high pass filter to 50hz (which the hertz speakers are rated for). Or setting the amp to "full" and setting the head unit high pass filter to 50hz?

Also what do you think is better, setting the VRMS to full clockwise and managing the hiss, or setting it to 5VRMS and having to turn up the volume on the head unit a lot more?

In response to my previously mentioned engine whine noise. This one confuses me because sometimes I can hear it and sometimes I cant. It's been too long that I can no longer tell if it's normal for my car or not. It's not that bad, I suppose. I'll live with it

 

[Meruem]

I used these settings today: http://i.imgur.com/LicyXeH.jpg and I'm pretty happy with it. In between 5 and 6. I don't hear any hiss at all unless I turn the volume up really loud with nothing playing. That seems pretty normal to me. Enjoyable loud listening volume is around 30 (50 is the max it goes to) on the head unit

Also on the head unit, I use "C.AUDIO+ (clear audio+) Reproduces sound by optimizing the digital signal with the Sony recommended sound settings: [ON], [OFF]. (Automatically sets to [OFF] when [EQ10 PRESET] is changed).". Not sure what it does exactly, but music sounds louder and clearer with it on.

high pass filter on the head unit is off and set to 50 on the amp. going to try 55 instead, because the bass is just a tad loose sounding on some songs