Hiss

OK, I have an AVN 6620 and I can't seem to get rid of a faint hiss (even when volume is turned down). From past experience I check the ground on the HU by jumping it to the chasis ground (no change in hiss). Next, I tested the RCA cables for engine noise. I connected the Ipod to the RCAs behind the HU (they still ran all the way through the truck to the amp) and there was no hiss. I disconnected the antenna wire (no change).

Through all of this I believe it's the head unit. Others have had cases with this HU hissing a bit but I'd like to investigate a bit further.

When i powered my HU up for the first time I had all the power/ground wires connected (I know better than to mess with that) but plugged the preamp RCAs in while the HU was on. The subs went boom a bit but all seemed ok. Can doing this cause a grounding problem (which intern causes the small hiss)?

My gains are turned up to about 4/5 on the highs amp so perhaps that causes the hiss.

I'll tell you though, for having 5v preamps this HU doesn't output any more volume than the Pioneer AVIC F700BT (it only has 2.2V preamps). Gains stayed the same for the same % volume when I switched HUs. Does that sound right to you?


Any help would be nice


David

 

Damn man we have the same taste and the same problem. Turn your ampilifier gain to about half way setting. The hiss should be gone. I've ran into more nightmares wiring this truck than I have any other vehicle. I also have the AVN 6620. As soon as I can I'll post pics of my new door panels. My AVN will run to two amps a JL HD 600/4 running two sets of C5 6.5" component sets and the 500/1 running three W3 12's. All JL wire.

 

Hey!

Are you getting hiss even with a good RCA patch cable? For 5v rca out does it seem that gains need to be turned up a bit high on the amp to keep volume levels low on the receiver? I too noticed how to fix the hiss but when I turned the amp to half gain I gotta turn volume way up to get loud sound.

David

 

I mean 5v RCA preout isn't a low voltage preout but it's not the highest. I tried using many deferent RCA cables and routing them three different ways. I still have a hiss but, it's gone with both front and rears set at half gain. Yes this means I have to turn the AVN 6620 to about 55-60 on the volume level. Still gets very loud because I have a 600watt JL HD amp on my components. I had a 300/4 before with no hissing noise and the gain was at about 3/4 of the way up. I didn't turn the receiver up above 35 volume. Right now I using JL RCA cables so there not cheap cables.

 

I have another quick question. Do you have to really lower the midrange (on the eq) to get good sound on this unit? I have loudness off and still have to crank the mids down a bit (else I get noise piercing overpowered low-mids).

 

I don't really don't get great sound unless the EQ boost is on the High or the Low setting. Stereo imaging in this model Tacoma is very hard to achieve. Any comment I've ever heard about component sets says, "In order to achieve good stereo imaging your tweeter shouldn't be place farther than eight inches from your midrange." Obviously if you mount your speakers in stock location your tweeter would be about 24" from your midrange. A very noticable diffence. I however fixed that by moving the midrange up higher in the door panel fiberglassing to sets of components in the door. I have two 6.5 midrange speakers and three tweeters in each door. The sound is phenomenal!

 

That fixed it. For some reason I was trying to avoid using the "Low" and "high" setting thinking it was trubass. Sounds great now. Outa curiosity, what did it cost you to do that panel work on the door? Did you do it yourself?

The more I get into this, the more I feel that the speakers belong in front.

Thanks!!

 

Yeah man let's face it I spent to damn much money on this truck in audio. First time I had two sets of XR 6.5's with ********* adapters in factory location pushed by a 300/4. For low end I had one 10W7 in a ported box. The component speakers in the rear are useless with any powerfull sub behind the seat. The only reason to put in the components or coaxial speakers in the rear is simple if you have someone riding back. You have two W6's really great speakers now you need to get another set of components and put them up front as well. I bet your W6's are loud.

Take the truebass off, leave the loud on under settings. Then go into your audio, hit EQ, and turn that on high for your highs. I bet you have turn the sub settings all the way to negative six.

Do your Focal front components have adjustable crossovers? I know mine sound great right know like there bassy but, when I put my three W3's in the new box I will have to set the crossovers to 2dB tweeter boost and I'll set the midrange on HIGH just like the AVN is set. This will allo me to achieve higher volume levels out of the components to keep up with all the low in the back.

Give me your email and as soon as I clean my door panels I'll send you some pics of them. You can look at spending about 400 a door panel. I did all the mounting of the logos, speakers, and the arm rest myself.