speaker wire question

[Art Todesco]

[SteveB]

You're talking to someone with about forth percent hearing loss from industrial noise, years of commercial diving (quick pressurizations, decompression chambers, 305' exposures, and training chamber runs of pressuring to 200' in forty seconds) and about seventeen too many ZZ Top concerts. Good enough is good enough for me.

I can barely tell the difference between a .357 round and a fart.

Steve

[Choreboy]

The problem is resonance. Many TVs have cabinets that resonate at varous frequencies. The sound from internal speakers will be noisy and distorted.

The resonance of a room can make a tape recording sound terrible. For ten years I listened to Koss Pro4AA headphones to avoid the resonance of room acoustics. Those phones usually performed better than speakers. In an ideal situation, good speakers could be better; the sound could be fuller and less harsh.

Then I read about damping factor. It was defined as the ratio between speaker impedance and amplifier impedance. Feeding speakers with a relatively low impedance can make a difference because speakers resonate. They are more efficient at resonant frequencies, and their impedance is proportionately higher.

My phones were 32 ohms, but receivers were usually designed to feed headphones through 220 ohms. At frequencies where the impedance was 32 ohms, my phones would be getting 1/8 the voltage from the amplifier. If, for example, they resonated at 500 and 2000 Hz and their impedance rose to 220, they'd be getting 4 times more voltage, or half the amp's voltage. In that case, feeding the phones through 220 ohms would make

500 and 2000 Hz harsh and other frequencies relatively weak.

It cost me only a few cents to change the circuit to a voltage divider with an output impedance of 0.5 ohm. This meant the voltage at my phones would be pretty constant for all audible frequencies. What a difference! The phones were clearer, less harsh, and had a wider, more even response.

I didn't have to go as low as 0.5 ohm. If I'd built a 3.2-ohm divider, that would have given me a damping factor of 10 with my 32-ohm phones. That would probably have been fine.

18-gage copper wire has 6.5 ohms per 1000 feet. If your speaker were 50 feet from the amp, that would be 100 feet of wire or 0.65 ohms. For a 6-ohm speaker, I imagine that would sound fine to most people.

28-gage copper has 66 ohms per 1000 feet. For a speaker 50 feet from the amp, the resistance would be about the same as the impedance of a

6-ohm speaker. I imagine the difference would be audible.

18 gage sounds big enough for speakers 50 feet away, but the OP might want to test it by hooking up one speaker through the wire he intends to use, then using to balance control to see if it still sounds as good as the other speaker.

The insulation on zip cord usually has a ridge along one of the conductors. That's how I keep my polarity straight with using it for loudspeakers.

[JustDave]

Oxygen free speaker wire is great! In fact, I use it for all my table lamps now. Makes the light purer and whiter. ;-)

JustDave

[Edwin Pawlowski]

Your nose is gone too, huh?

[User Example]

Who cares what it sounds like as long as it is loud.

[Choreboy]

When you opened this thread, you asked, "Will adding longer wire affect the sound?" Were you joking?

Some have said wire resistance doesn't matter with cheap speakers. I think it matters more. Cheap speakers have worse resonance problems, which means they will be more affected than expensive speakers if both are fed through too much resistance.

I think the same applies to those of us with damaged hearing. Aren't we the first to have troubled understanding conversation at a party in a room with bad acoustics? Likewise, our ears are less able to accommodate uneven speaker response.

[SteveB]

I wear hearing aids, and have done so for about two years now. If I knew they were this great, I would have gotten them ten years ago and saved myself one million "Whaaaaaa?" 's.

For now, my hearing is so skewed that I don't remember what it is like to hear clearly. So, I just want to have things fairly correct so that I have an even chance of hearing things the best I can.

I have two JVC cabinet speakers, pretty good for their time. I would say they are about 20 years old, but in very good condition.

Would I be ahead by taking these better speakers and putting them on the smaller Magnavox system? Would it be advisable to use four speakers, hooking two to each channel? I just want to listen to music at low levels, but at least hear fairly close to what is being put out by the amp. The unit has a graphic equalizer on it, so I can tweak it a bit.

For anyone with hearing problems, I cannot stress enough how much hearing aids have helped me in so many ways.

Steve

[Choreboy]

They may soon need work. I have 4 hip-high EPIs and two smaller ones, all about 20 years old. A year or two ago Louis Armstrong's cornet started sounding scratchy and I found that the foam surrounds in the four big woofers were crumbling from age. I replaced the foam for $40 plus my labor. Now I wonder how much longer the midrange surrounds will last, and I haven't checked the little speakers.

For the best sound, I'd play the two better speakers alone. The other speakers could be used to play in another room. If the amp output is through a capacitor, running them at the same time will reduce bass response. The increased current might blow the amp.

As a boy, I could hear a mosquito anywhere in the room. Later I served on a ship with a winch that ran long hours at sea. It had been converted from electric to hydraulic. The hydraulic lines brought a very loud mosquito-like whine throughout the ship. I hated it. My hearing was tested when I left. It was diminished in the 3k range. The doctor said it was true for everyone aboard. After that, my ears wouldn't warn me of the presence of a mosquito. I need to get a pet bat for protection!

[~^Johnny^~]