PA hiss

B

bluesbro

New member
Hi All,
I finally bought my PA (well almost). A new Crate csm16 mixer & and a spa-200 amp. I am using 2 - new 12" with horn monitors till I can afford some mains.
This setup hisses pretty loud. My question is how can I elimidate the hiss? My first thought is the cheap amp 100w RMS stereo into 4@ ohms. I am using 8 ohm speakers. Can someone clarify the watt rating ohm thing? All cables are new. It is hooked up via mixer L&R channels to L&R channel on amp with 1/4" cables & correctly. Speakers are 10' from the amp and 10' from each other.
Sound coming thru mics sound good and not distorted. However, I just can't live with this loud hiss.
Any help or thoughts would be greatly appreciated.
Thanks in advance
John
 
Well I reduced the hiss in half by plugging the amp into another power source. I guess a power conditioner will do the job.
The noise is still there but not as bad.
Any other suggestions on how to get a PA almost dead quiet?
 
if PA is on same circuit as lighting system, put pa on different circuit. Sometimes you will get a 60hz hum.

another thing to do is that sometimes those pre's on the mixers are noisy and if you put the faders/knobs to zero this will cut down on hiss.
 
Check your gain structure for one. And... well, that's all I have.

Many times I find myself pushing the faders and a hiss develops. It usually takes me a few minutes before I realize I could fix it easier by pushing up the trims.
 
All PA systems have some type of power hiss. You are usually pumping a lot more power through PA speakers than studio monitors. I've never known Crate to be a high quality mixer mfg so chances are it is just a noisy mixer.

Is the hiss bad when music is playing?
 
The music is fine. I had my reverb box turned to high on the post on my mixer. The hiss is now almost gone. I have to put my ear about 3 feet from the monitors to ear it. One problem gone.

Next problem is feedback. I have 5 cheapo Samson & shure 58 mics on vocals. The problem is I cannot get enough volume out of these monitors before feedback occurs.
My drummer's sound is louder the the damn monitors.
I have played with all the mixer levels and settings without success.
I have moved the mics all over the room trying to find a place where they do not feedback. No Luck.

Any tips or suggestions.

Sorry for the basic ? 's this is my 1st PA system. I'm learning.
Thanks
John
 
If the feedback is in your rehearsal room you need to deaden the room more. A small reflective room with a drummer and a PA is a sure recipe for feedback problems.

The 58's should be fine but the Sampsons probably dont help. Make sure the speakers are as directly off axis (behind) the mics as possible.

You can try a parametric or graphic EQ and cut the frequencies that are causing the feedback. This will affect your sound so use sparingly.
 
Thanks All
Well I solved the feedback, hiss, low volume problem. It was the cheap Crate amp I was using for the monitors. I hooked up an QSC 2404 (?) and everything sounds perfect. The crate amp makes a popping sound every now and then, especially when you turn it off. It Pops (loud) 5-10 seconds later every time you turn it off. It must be defective. Anyways, I am much better off with the QSC amp. I"ll return the crate for another QSC amp.

Thanks everyone for the support.
This is a great forum.
John
 
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