The perils if having nice speakers,,,,, (1 Viewer)

[Jonathan T.]

So I finally started upgrading my speakers. I started with the mains of course going from som Yamaha barely better than HTIB speakers to some very nice Infinitys. Man, I can't even describe what a difference there is, but I am sure you all can relate.

But as I tend to get whenever I make a major purchase, I have been a little paranoid about blowing them. (BTW, can you blow a speaker by playing it too loud if there is no distortion of any kind?)

Today I noticed a very noticable hiss coming from my speakers when I was playing my star wars sountrack cds. It got louder if I turned the volume up and quieter when I turned it down. Immediately I suspected the speakers because I never heard the hiss on my old speakers. (do blown speakers ever hiss?)

I started looking around online and read about a test to see if it was the amp was the culprit. I turned it to an unused input and cranked the volume. dead silent. ok so its not the amp. good.

maybe it was the dvd player? but wait a minute, would there be noise on all cds? i tried a few others. I noticed that the noise was worse on live recordings, and i guess the star wars discs being orchestral music would have been recorded live, eh? so now i am at least 95% sure its the source material. But I did one more test, i ripped a track from one of the noisy discs and loaded it up into goldwave and filtered out "hiss". burned the same section of the song, back to back, the original unedited track, and then the cleaned track. well, I lost a little bit of detail from the recording, but low and behold no more hiss coming from my speakers.


So in the end, my speakers arent broken, my amp puts out a completely clean signal with no hiss of its own etc. And I have leanred that good speakers are a double edged sword, they make good recordings sound amazingly good, but they also make even slight flaws in a recodring very obvious.

Couple more questions:

Though I am not a big fan of MP3s, I do have a small collection. Sime I ripped myself, others I um, found...

The ones I ripped on my own sounds decent, but many of the others have very major pops and clicks, some really loud and jarring. I am wondering if playback of these pops and clicks can damage my speakers?

 

[Steve_D]

Yes, the double edged sword of resolution...every flaw is exposed. I can even hear a difference in the sound when the Air Con or heater fan is on or not. For me, I got to the point of wondering if I had gone as high as I wanted to go due to the fact that some of my favorite recordings were not so well recorded...I got over it.

The recorded pops and clicks are not good for speakers...you should be fine as long as you keep the volume reasonable...but I would try and find a better recording. Allofmp3.com is so reasonable, I'd give legal music a try

 

[Jonathan T.]

Got nothing against legal music, own an awful lot of it in fact, and I buy two or three cd's a month. When I download and mp3 it is for the purposes of smapling the music before I buy an album, and if i dont buy the album, it's because i didnt like the music much, so it gets deleted anyway. I think that's fair, whether it is excplicitly legal or not Some of the mp3s I have have been downloaded directly fomr the artists websites.

 

[LanceJ]

Yes. Though surprisingly, smaller amounts of distorted power has more potential for causing damage first because distorted power can contain clipped waveforms which resemble square waves--very nasty stuff for ears and speaker voice coils alike. Again, tweeters are more susceptible to being damaged by this than woofers are (a tweeter's voice coil has hair-thin wire compared to most woofers which use much thicker gauge wire [I'm guessing about 20ga or so]).

 

[Jonathan T.]

Okay, got that, but what I need to know is that If I am listening to my speakers and they are loud, but there is absoloutly no distortion, am I safe? I mean, if I am in the dnager zone, will i hear it?

 

[Lewis Besze]

Yes you're safe!

 

[Jonathan T.]

one more question. if my speaker were damaged would I know it? is it possible to have a blwon speaker that still sounds fine?

i know im paranoid beyond belief, but I can't help it.

 

[John Garcia]

There is pretty much no such thing as no distortion. I've never seen an amp that could not be turned to the point where it will run out of current and eventually damage the speakers. It is too LITTLE power that causes the problem (clipping), not too MUCH. So as long as you aren't reaching that point with your receiver, you should be OK.

No, it is not possible to have a speaker with a fried voice coil that would sound fine. Tweeters will generally just stop working; larger drivers may continue to function, but they will not sound "right".

Hiss does not always mean there is something wrong with your system. Some hiss is relatively normal. Unless it is audible in the presence of a signal, don't worry too much about it.

 

[Jonathan T.]

I guess that point must be in the realm of uncomfortably loud, because I have cranked my system up a loud as I can stand it, and its still very clear with great dynamic range.

 

[John Garcia]

Well, I guess that's a good thing. I can turn my system to uncomfortable levels with it still sounding clear too, that does not mean distortion is not present, it is just not at a level that it is intruding on the sound yet.

Hiss is frequently part of the recording, and live recordings obviously do tend to have a bit more background noise. If you dial back the hiss, you are likely killing off some of the upper highs as well, which could be part of the reason why that "hiss" was left in originally.

 

[LanceJ]

Yes.

But just remember the warning signs I mentioned above when the speaker is being overdriven. And IMO by the time the woofer is making nasty noises, the tweeter will be O.K. for the time it takes to pick up the remote & lower the volume. This is also assuming the treble control isn't turned all the way up--then the tweeter probably will lose that race (I've seen this happen).

BTW: I worry some about the people that are using very powerful receivers with small sats* because unless the sat's mid and/or tweeter is crossed over high enough or with a steep enough xover slope, the mids and tweeters are susceptible to burn-out, particularly with movies or music like classical that have wide--and unexpected--dynamic ranges. Don't forget that the receiver's bass management system only extracts certain bass frequencies from the front/center/rear channels, and not the ones the midrange & tweeter handle. So unless a speaker is specifically designed for a bass-managed system, in my opinion its published power rating is only accurate when it is being used with a FULL RANGE signal; otherwise the woofer will not give its typical warnings while the tweeter slips quietly into the Great Beyond............

* i.e. something with smaller than a 6.5" woofer.

 

[Wayne A. Pflughaupt]

Jonathan,

Sorry to be the one to break the news, but the hiss “problem” is your speakers. The good news is that it really isn’t a “problem” at all. What happened is that you went from relatively low-fi speakers to a nice pair with extended high frequency response. In other words, the hiss was always there; you never heard it before because your other speakers weren’t reproducing it!

So yes, as Steve D mentioned, good speakers can be unforgiving of poorly-recorded music.

Regarding what damages speakers: Basically for woofers or tweeters, it’s a problem of the voice coils overheating and burning through. When this happens you have an “open” connection across the speaker’s terminals, so it can’t work anymore. With woofers, if the voice coil didn’t get to the point of burning through, it can be damaged so that it makes a scraping sound when the cone is moved. This can be hard to diagnose, but it shows up most readily as a subtle buzzing or distortion at low volumes, most noticeable with simple program sources like the spoken voice.

Typically two things will cause voice coils to overheat.

The first is driving them with a wide-open amplifier. A crude example of what happens: If you remember cassette decks and their LED recording level meters, the meter would normally have a good amount of “bounce,” reflecting let’s say 15 dB or so between the signal peaks and lows. But what happens when you raise the record level? The meter hits the top of the scale, and can’t go any higher. The low end of the signal moves up towards the top of the scale as the dynamic range reduces from 15 dB to zero. If the record level is turned up high enough, eventually the meters do not “bounce” any more but are full-on.

That’s a visual of what happens when you drive an amplifier wide open. Dynamic range decreases to zero, so you now longer have fluctuating power (signal peaks and lows) going to your speaker. As such, your speakers are getting a constant, steady-state voltage. Speakers don’t like straight voltage because there’s no cone movement (which acts as air cooling), so voice coils heat up and eventually melt through.

The second thing that can cause speaker damage is playing them at high levels for extended periods of time (parties are a common culprit). This can eventually overheat the voice coil despite cone movement. Just how soon that happens will depend on the speaker’s power handling capabilities and how close to maximum the amplifier is running. Program material can be a contributing factor – for instance, hard rock music, which is typically highly compressed (thus limiting dynamic range) will fry a speaker long before a recording of a three-piece jazz ensemble, because the amplifier’s output voltage will be more constant with the former.

I some cases the speaker’s crossover can be damaged, although that’s not nearly as common as damaging or blowing the drivers.

With all that in mind, let’s take a look at some of the questions and comments posted above:
You’re not necessarily safe, and you won’t necessarily hear a problem. Naturally, if you’re bottoming out a woofer you’ll know it and you can stop that by turning down the bass. But even if you’re not hearing distortion you could damage your speakers if they’re played loud and long enough. This would be especially true in the case of say, a high-powered amplifier driving smallish speakers.

Any way you cut it, it’s not a good idea to play speakers at high volumes for prolonged periods of time. Most home speakers just can’t take that kind of punishment. If that’s your preference, you should look into professional-grade speakers, perhaps studio monitors.

Regards,
Wayne A. Pflughaupt

 

[Jonathan T.]

Thanks wayne, actually I already figured this out, hence the subject line and content of my first post....


As for the rest of your response, very helpful. I am fairly confident that even though I classify my listening volume as loud, it is still within reasonable limits. And it's usually not for more than an hour at a time with music, or two hours for a movie.

One thing you didn't comment on where the pops and clicks present in som of my mp3s. That's probably my biggest concern.