I have an old sony amp connected to two (quite old) speakers, a few inches across. The problem is, when I turn up the volume especially if there's lots of bass, one speaker channel (it's stereo btw) cuts out, I've verified that it's not a problem with the speaker because the same problem happened even when I swapped the speakers around (to the other speaker, now on the same channel). What happens is the sound suddenly gets completely distorted and makes 'crunching' sounds - turning the volume back down doesn't fix it, the only fix I've found is to leave it for a while. I suspect it might be a component in the amp overheating but I really have no clue what is causing this.
You are generally causing this would be my guess. You are very likely clipping the amplifier which causes overheating and the amp shuts down to protect itself from abuse. You are also risking damage to the woofer as the crunching sound could be just the distortion from the amplifier but is more likely also the crunching of the voice coil being banged against its start/stop positions.
The answer with this amplifier/speaker combination is to turn down the bass and turn down the volume.
Thanks. Right now I have both speakers hooked up to one channel, the one that works, and the problems have stopped (for now). Do you think this is a bad idea btw? I'm not sure if the amp is designed to be able to cope with two speakers on one channel.
Well, you do point out this is a stereo amplifier so it is intended to have two channels of information playing through two speakers with one on each channel. You are missing one channel with your present connection. Music can't sound its best with one channel missing.
As far as the amplifier is concerned I doubt it is all that happy with two speakers on one output. If you've just jammed all the wires into the red and black speaker outputs of one channel, you've placed the two speakers in parallel which will show the amplifier half of the lowest impedance point of either speaker.
In more layman like terms you're f'ing with the amplifier's ability to stay in one piece.
If the amp is handling the two speaker/one output channel connection but doesn't care for the speakers connected as they should be, then you need to first check for obvious problems and then secondly make a decision. Any single strand of loose speaker wire can short the outputs of the amplifier and shut down a channel. So, it would be wise to make certain you've made nice clean connections in all locations before you proceed. Speakers should only be connected/disconnected when the amplifier has been powered down and allowed to sit for at least a minute. The amplifier might be running without shutting down at this point simply because you've removed the poorly connected speaker cable from where it was shorting.
When you make your connections be certain you have the speakers connected in phase with each other or bass quality and content will suffer. If you have no idea what "in phase" means to speaker connections, please ask as I'd rather explain something simple than explain why you have managed to blow up your system. In short, it means red goes to red and black to black at all connection points. The speaker wire is marked in some manner to allow easy identification of which leg goes where. Make certain you understand this or ask for clarification.
Next, place your speakers on the floor and in two corners of the room for maximum bass boost without cranking the bass control.
When anyone tells me they do not have enough bass or their amplifer is shutting down when it is handed lots o'bass my first inclination is the problem exists with the nut behind the volume and bass control. That would still be my inclination here since you've not disputed my first post. Turning down the volume to a reasonable, non-clipping level is the first suggestion. Lowering the amount of bass boost you ask of the amplifier is the second, coincidental suggestion - see the speaker placement suggestion above. Both suggestions should be taken together as they sympathetically affect each other.
If you want more bass than your present set up allows without risking damage to said components, buy a decent subwoofer. "Decent" meaning not some piece of junk that pretends to be something it is not. You'll need to spend a few hundred pounds on a good subwoofer or don't bother at all and live with your present system as is until you can upgrade. Throwing money at a problem isn't the best way to resolve issues such as yours but available, liquid assets do provide more options.
As most posters do you have not provided sufficient information to really assess much of what could be going on with your system and I tend not to extend my mind reading prowress to simple posts such as yours. "Really old" is meaningless to anyone over 16 and even more so to someone who uses 50 year old amplifiers on a daily basis. However, parts do fail and some of them fail gradually over time while others are pushed over the brink by that nut I mentioned earlier. Your decision is whether you continue to abuse this amplifier or not. Would you take a thirty year old car and drive it 100 MPH? Let's hope you have more sense than that on many levels. Chances are you are simply asking too much of this amplifier and you need to realize its limitations before you destroy it.
You sound very young by my standards and that too often means you still have a lot to learn. I will advise you that in audio the learning curve is all too often accompanied by blown up components and speakers. That's a shame in my opinion when a little common sense and a few questions asked could have prevented the destruction of audio equipment. Components and speakers have their limitations and they are found long before the volume control reaches 11. Excessive bass only makes for lower overall volume settings. With the tone controls set flat the upper limits for most receivers or amplifiers is at about 1 O'Clock on the volume control setting. After that distortion sets in and it will damage components if left unchecked. If you turn the bass control up, then you need to lower the volume control to compensate for the extra power consumed by asking for "more bass". Virtually every audio system operates within these same set rules. There are few exceptions here so you might as well memorize that rule right now, it will serve you well in the future if it does nothing more than save you a bit of hearing damage thirty years from now. Your ears should not hurt or ring when you turn off your audio system!
There are ways to get what you want from other components. If you have the monetary means to buy new components, you can turn your system into a bass mongering free for all which will allow the local constabularies to memorize your name and address at all hours of day and night. However, with the present system you describe, if this is where your budget places you and you would be hard pressed to make substitutions for fire damaged components, you had best learn to work within the confines of your present limitations or you will not have any system what so ever in a very short time.
I hope I've made the above message very clear. I was provided for your own good.
Lol, well it's still working, it's old I didn't pay for either component (speakers found in a skip, amp is from an old friend who didn't need/want it any more). It seems to be handling the two speakers on one channel, and yes they're in phase although it doesn't sound very different when it's supposedly out of phase. I made sure the wires were clearly indicated polarity-wise when I soldered them to the speakers a while back.
If the whole thing breaks I'll just say sod it and use my spare pair of rubbish desktop speakers (and that old bass-guitar amp I have lying around), until I've found the spare cash to get a decent amp and speakers.
Oh by the way, I am and always have been careful with the amount of bass I have, I make sure it sounds clear and isn't distorting or cutting out, if it is I just turn it off). Although the amp is hooked up to my PC and video games have been played using this amp - I'm talking grenades, explosions, gunfire, and other chaos...all in all I wouldn't be surprised if both the speakers and the amp are on their last legs. But take note, the speakers sound fine when only connected to one amp channel.
As long as the amp is stable into 4 ohms (assuming the speakers are rated at 8 ohms and the amp is solid state) running only one channel is no more or less of a load than running both channels.
It does sound as though the other channel is shutting down in protection mode. The crunching noise could be voice coil or distortion in nature.