miggy

So I just got new speakers and an amp for the car and when I put the volume really low I get a very noticeable loud hissing sound. I saw this thread
https://www.scionlife.com/forums/vie...hlight=hissing
and was wondering if just doing that will help the problem or do I need to to do something else? I do plan on getting a new head unit and I assume that will help with hissing or will it? Thanks in advance for any suggestions.

blubox04

make sure you don't have directional rca, that could cause it.

miggy

I am not going to feel good asking this but, What is that?

Winter

that is deffinently one cause of the problem. another is cheap signal cables *ie* RCA cables.

i'm not sure if you want to spend the extra cash BUT, from my expierence in studios, a Brand name of Mogami is widely used. Mogami has many diffrent type of cables for you to choose from. if it;s not the right length or whatnot, you can go to your nearest Guitar Canter and do a special order from the "pro audio" department of the store.

Mogami sheilds thier wires and cables so nicely that there is a 98% noise reduction meaning no more "hiss". this "hiss" is known as "cable noise" and is very annoying as you've noticed...

there are other brands out there that provide simular sheilding but i garuntee you, you will not find ANYTHING better then Mogami's.

if i'm not mistaken, sheilding rates are as follows:
Mogami = 98%
Monster Cable = 82%
Livewire = 45%
Hosa = 15%
generic brand = 10% and below.

miggy

Interesting, good to know. I am going to see how much that cost, because that thing is pretty loud when no volume is on.

Winter

Mogami cables are expencive... don't be suprised to spend 30-50 bucks on a singel cable. but well worth the buy!

they can only fix cable noise though, part of your hissing may also be not enough grounding aswell, but both grounding and cable noise are causes of the Hissing factor.

DriverXa

check your ground wire, may need a heavier gauge and/or a different grounding point.

miggy

Before I go in to the shop and ask them to probably replace the wires with something better. What am I looking at price wise? Any rough estimates? So I know I am not getting screwed. Thanks.

teaBAG

the gains may be too high on the amp. how was the system tuned. depending on the deck, when there is no signal(voluma e all the way down) the deck amplifies anything it can find.

UV7

Before you go purchasing better audio cables, check the free stuff first. Does this "hiss" seem to go up and down in pitch with the RPMs of the motor? If so, then you obviously have a ground loop. This happens when there is a variance in potential between grounding points in the vehicle. Ultimately, EVERYTHING would be grounded at the same location, but this just isn't possible. To resolve the situation, you will need to verify that the ground for the amplifier is as good as possible. Ideally, the ground would be directly to the frame, but since the amp is inside the cab of the vehicle, using a bolt that makes frame contact will work. The ground point needs to be clear of all debris, finish, and paint. The surface should be smooth and down to bare metal. Also, your ground connection should be the same gauge wire as your power to allow even flow of electricity throughout the circuit.
The other common source of ground loop issues is the ____ POOR ground connection for the factory stereo. If you have replaced the factory HU with an aftermarket unit, do yourself a favor and run a better ground rather than using the factory connection.
Any variance in potential from one ground to another can cause a ground loop issue, so using the best possible ground for all your audio electronics is the safest way to go.
It is possible that your audio cables are suspect, but it is also possible that your power or ground cables for the amplifier are just too close to the signal cables themselves, thereby causing interference in the signal. Keep your signal cables as far away from power and ground wires, as well as ground connections, as possible.
Check these things out before you go spending $$$ on good quality audio cables. Good cabling is not cheap.

SCI_TC_GUY

Read through my post here:

https://www.scionlife.com/forums/viewtopic.php?t=104153

and see if any of that can help.... even with cheap wiring, you CAN avoid most noise inductance

miggy

Thanks for the info. Now I really don't know how to replace or move around these wires to better the situations. That said, if I take it somewhere to get that done, what would you say is a rough estimate for doing that? Thanks again for all your help guys.

Winter

depends on what you want to use and how much they charge for the labor.

hopefuly if the installers know what they are doing, they will make sure your grounding is done propurely and away from audio cables.

something as a reference though that i remembered. if you do go the Mogami route, a true fact about these is that you could have them side by side to upto a -8 guage power cable *ie* a main "out" generator cable and still not get any transfering inductance noise.

i really can't say anything at all that will be interesting enough to make people say "OOO I'M GONA BUY IT NOW!" but from my experience, if i was going for SQ i would deffinetly get nothing but Mogami's.

UV7

Typically, you can expect a shop to charge you their normal installation fee per device, simply because that is what they will essentially be doing. This can vary anywhere from $50 to $150+ per device depending on where you take it and what all is done. Many stores will want to replace the power, ground, and signal cabling that was originally used in order to properly guarantee their installation is free of possible noise rather than go through the trouble of inspecting and testing what is already installed.
I recommend that you at least trace the ground for the amp back to its grounding point and verify it is a good solid ground connection prior to spending additional $$$ on a professional installation. If you are willing and able, trace the ground wire from the amp back to its ground point and then come back and post where the setup is currently grounded. If you have a camera handy, post a pic of the amp and its ground connection. We may be able to help you sort out your signal noise simply by addressing the ground point. After all, the majority of signal noise is actually introduced by poor ground connections.

miggy

Thanks UV7 I'll do that. I probably wont get a chance till tomorrow to do this. Hopefully it just this. Thanks again.

miggy

So I hope this is what you asked for if you need different pics please let me know.

SCI_TC_GUY

Bad #1
Grounding point is on a painted, curved surface... That should be grounded to a flat part of metal that is sanded down to only metal (no paint/debris)....

Bad #2
RCA's are ran right next to the power wire going to the amp... seperate them with Power on one side of the car and signal cables on the other side of the car....

miggy

Well then, either they really don't know what there doing or they figure they I would assume the hiss is normal. So now I need to get that fixed. Before I do, any more problems that anyone notices? and this anyone have a recommendations for a place that you have been very happy with? you know good service and good price? I am in West Los Angeles close to UCLA. I don't going further away to a place as long as it is done right. Thanks again for everyones help.

Winter

if you debolt the rear seat, sand down one of the bolting holles and make sure the ring on the ground wire is bigging then the thread of the bolt, put it there, that way it's not just on a suport bar for the rear seat but on the actual underbody of the box. it's perfect for grounding and get rid of alot of the problem. but also like TC guy said, your RCA's should not be ran along side your power mains. if you can, put them on the complete opisite side of the vehicle to that of where your mains are ran.

i would still recommend higher quality sheilded wires aswell.

Winter

an example...