help with speaker setup

Ok, I recently bought two brand new floor speakers with a maximum of 400 watts a piece. I have an amp to go along with them. The problem is that when I turn the amp up to about 1/4 of the maximum wattage I begin to hear scratching noises. I listened to the speakers in the store before I bought them and they let me turn it up much louder than I try to turn my up. Anyway, I am wondering if the problem could be the wires going from the amp to the speakers. Are there special wires that will carry a higher wattage? could this be my problem? The reason I ask is because the wires are the only thing I have that aren’t new, they were on my old speakers which had no where near as much available wattage. Is it possible to output too much power for the wires to handle thus resulting in poor sound quality ? Or is it something else ?

Audiophile and electrical engineer type checking in.

“scratching noises” isn’t terribly descriptive so I will hit a couple possibilities here.

  1. There could be a manufacturing defect in the speakers, if you do here a rubbing or scratching sound, it could be the bass drivers are rubbing somewhere in the suspension or voice coil. This assumes that you got a new in the box pair and not the pair on the floor, or they could have been damaged in transit in either case.
  2. Innadequate speaker wire should not cause any problem that sounds like what you are describing. Good speaker wire should be low inductance, low capacitance, and low resistance (the last usually being the largest source of problems). Small gauge wire will noticable muddy the bass response (do to relatively high resistance). The first half cycle of a good bass drum kick uses alot more current (and power) to get the speaker moving from a stop. Cheap, skinny wires limit this short term current and take the snappy feel out of good percussion. With very highend equipment and experienced ears, small changes in sound quality do to inductance and capacitance in the wires can be heard. For most people, the heavy gauge wire available in most retail stores is adequate.
  3. Is the amp up to the task of driving those speakers?
    btw, the email in my profile is legit… feel free to use it. I am also in TX and would be happy to troubleshoot on the phone with you if necessary.

Is it a new amp as well? The problem is almost certainly in your amp.

It sound to me like the potentiometer (the dial or slider controlling the volume) is dirty. Basically, little flecks of crap in the dial interfere with the operation as you increase or decrease volume, making popping or scratching noises. You can try blowing it clean with a can of pressurized air, or open it up and get in there with a Qtip.

My only thought other than what had been mentioned is to be sure that you don’t have your CD player plugged into the phono section of your pre amp/ receiver.

I doubt it is a wattage issue. “400 watts” is a max rating. If your speakers are a typical 87db efficient model, this means that up until 87 db you will only be using a fraction of 1 watt to drive them. The scale is logarithmic after that, so 90db takes 2w, 93db takes 4, 96db = 8w, 99db = 16w, 102db = 32w, 105db = 64w, 108db = 128w, 111db = 256W. Not many people want to listen to 111db for very long.

My speakers are only 83db efficient, (which is pretty damn inefficient) and my ears give out well before my ears, and this is with a 200 watt/channel amp.

What load are the speakers putting on your amplifier? 4 ohms? 8 ohms? 2 ohms? Your amplifier might not be able to drive the speakers.

The ‘scratching’ that you’re hearing could be a rip in a driver, or manufacturing flaw.

You could help us out with some more details. What are the brands and models of speakers/amplifier?

Another thing that’s not clear. You say that you’ve only got the volume up to ‘1/4 of the maximum wattage’. What does that mean? You’ve got a 100 watt amplifier cranked to 10? Or whatever your amp is is only turned up 1/4 of the way?

BTW, don’t take that wattage rating on your speakers too seriously. The true situation is a lot more complex than that. And if they are cheap speakers, that 400watts could be peak power, not RMS, and even at that could be meaningless.

Distortion is what kills speakers. If you are hearing ‘scratching’, you are possibly doing damage. The moment you hear any distortion at all in your sound, turn the volume down until it goes away.