Possible to eliminate that slight hiss? [Archive] - Audio & Video Forums


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07-12-2004, 01:23 PM
I've become accustomed to having my speakers audibly hiss when I turn them way up. Usually it's not an issue, because most of what I listen to is relatively loud. With extremely quite sources, though you can sometimes <i>just</i> hear that hiss. Seems like it's been like that with every audio system I've ever owned.

Is this something that it's possible to eliminate/greatly reduce? Will using only shielded speaker cabling alleviate the problem, or is this just "one of those things sound systems do"?

Thanks for any help.

07-12-2004, 01:42 PM
Is this something that it's possible to eliminate/greatly reduce?
There are a number of strategies for lowering the noise floor, depending upon the source. It might help to clarify your situation. It is quite normal for most preamps / receivers to have far more gain than necessary to fully drive an amp. Cranking the gain control to the maximum clockwise position is not a practical test. Hiss with a CD source should really be non-existent. It is more common with vinyl sources with their higher gain stages. Which is it?

Proper cable routing and separation of signal vs. power related cables is key. Cleaning all contacts using products like Caig's Pro Gold can help. Isolating other kinds of devices on the same power line can help.

Will using only shielded speaker cabling alleviate the problem, or is this just "one of those things sound systems do"?
Shielded speaker wires will do little for perceived hiss, but shielded ICs can. Sound systems really shouldn't hiss. Mine does not even with vinyl.


07-12-2004, 01:48 PM
A bit of hiss is quite normal in any powered circuit. It's created by heat, which is generated by electricity running thru the circuits. When you turn it waaaay up, you're amplifying all the noise generated in the previous stages.

Generally, the better the electronics involved, the lower the hiss but it's always a possibility.

This noise can be accentuated by having speakers with an upward tilt (bright), turning an amp way up and/or sitting very close to the speakers.

Now, you can try the tricks mentioned above, but don't expect it to go totally away. To a great degree, I'd agree that it's "one of those things". People expect total silence and it just ain't gonna happen.

07-13-2004, 05:18 AM
I think that about answers my questions. Thanks for the responses!

07-13-2004, 09:36 AM
I think that about answers my questions. Thanks for the responses!

Well, since you've got both my son's and my name in your name, I feel compelled to reply.

Over the years, either my hearing has become selective, or I've discovered that you can have a virtually dead silent system, even at high volumes. The reason I say "selective" is that I can certainly hear the hiss in some of my acquaintance's systems, but I never hear it at home in my #1 and #2 systems, though I do hear it a bit in #3.

Of course, your system is going to be as hissy as the component(s) with the most hiss, unless there is some mitigating component between it and final sound reproduction. So, you really have two goals: 1) eliminating (or controlling) as much hiss generating componentry as possible, and 2) suppressing or mitigating the hiss that exists.

Here are a few suggestions that work in most typical home systems. (Some help with hum as well.) If you've got a monster (meaning big, not Monster) system, then hopefully many of these things were taken into consideration by the designer/installer.

1) Plug all elements of the system into the same electrical circuit(s).
2) Use a noise filtering power supply/surge suppressor. (Not recommending any brands or configurations here.)
3) Make sure input connections from TV, cable, satellite are tight and properly grounded.
4) Eliminate all dimmers, motors, servos, toasters, etc. from the circuit. (In fact, a dedicated circuit works better.)
5) Route power cords and component interconnects on oppposite sides of your rack, stand, or entertainment center.
6) Keep all coax cable separate from power cords AND interconnects.
7) As much as possible, "drape and shape" interconnects so they don't lie together in a tight bundle. This is especially true for those that go from components to pre/pro and those that go from pre/pro to amplifiers.
8) Route speaker wires away from power cords AND away from interconnects.
9) Try to keep a bit of separation between speaker cables that must follow each other in parallel runs.
10) Keep speaker cables away from electrical wiring. It's in the walls, and sometimes in the ceilings and floors. For example, if your listening room is above the garage, there's wiring for the garage lights and garage door opener, plus the light fixtures (flourescent or incandescent) and opener motor, in or immediately below the floor of your room.
11) Make sure speaker cables are securely attached at both ends. Pull on them to make sure they're seated well. Don't assume because the nut is tight that the connection is tight.
12) Test the effects of inserting your components' plugs in both ways if the polarity isn't readily determined.

Beyond all this, your equipment needs to have a very low noise floor. My Fosgate Audionics FAP-T1 and Citation 5.0 based systems start with pre/pros that are renowned for low noise floors--so low that I can't hear them. Same with the amps and other components: the less noise the better.

Use the right combination of components (including speakers) and the best equipment set up, and you have a virtually silent system at any volume level. If one or more of your components is noisy, there's no help for it, although some of the steps outlined above may help.

Looking at the S/N (signal to noise) ratio can help, but it's not the only consideration. Anything better than about 80db is tough to distinguish at low volume levels, but increasing the volume level can introduce an audible difference. Components that have a S/N ration above 100db fare better as the volume gets louder but don't have any real advantages at normal levels.

Some good info and troubleshooting tips can be found here:


07-13-2004, 06:18 PM
...anyway. I bought a new (well, new for me) preamp, and when I used it, it seemed to have more background noise/hiss than I cared for. Remembering that its internal gain was adjustable, I took the top off and fiddled with the little DIP switches, to change the max gain from 19dB to 3.5dB. Backgrounds are very quiet now. The gain is still sufficient.