Speaker power handling

[Goliath]

Hi everyone,

Today I was playing some music at quite a loud level, not sure what the dB reading was, but it was loud. I have Polk RTI-A3 speakers and an Onkyo 515. It is 130 watts 6 ohms. I heard a weird sound coming from the tweeter, it sounded like heavy distortion and I turned it down. Problem is that distorted sound is still there, no matter the source.

My question is, how would I improve volume and prevent this from happening again? Buy a speaker with a better handling capability or a bigger amp? I could turn the volume down but I like my music loud.

 

[ski2xblack]

You have to figure out a few things. The basics are your room size, your desired listening level, the sensitivity of your speakers, and their upper spl and power handling limits. Also keep in mind the logarithmic nature of power demands for greater spl. It's a juggling act, and there are limits, which it seems you have met in your system.

With the information presented, I'm guessing you fried your tweeter, probably from sending it a horribly clipped signal with more high frequency content at higher power levels than it could endure. If it's scratchy at all volumes now, you have a part of the voice coil that has gotten too hot and managed to unwind itself, rubbing against the magnet.

Using the same Polks, after you replace the fried tweeter, with a more powerful amp may help you avoid clipping, but will increase the risk of thermal or mechanical damage from simply applying too much power.

I'm a big proponent of higher sensitivity speakers, as they sidestep this issue, and in many cases have lower distortion measurements to boot.

 

[Goliath]

My room is 5 x 6. I sit 3 meters from the speakers.

Here are my speakers :

RTiA3 - Bookshelf | Polk Audio®

If I were to upgrade and get these :

RTiA9 - Floorstanding | Polk Audio®

Would they be better equipped to handle the high volumes? I ask because the tweeter is the same, so I don't know if the tweeter power handling is the issue. Bass wise I'm sure I'll have much nicer and deeper bass, but if the tweeter is the same, I don't want to run into the same issue.

 

[ski2xblack]

I don't see any sensitivity specs on either of those product pages, but assuming you can dig that info up, you may want to try this calculator. I've found it fairly accurately reflects real measurements in my rooms. It would certainly help elucidate what's going on if you have your own spl meter so this is not just a shot in the dark, but a useful exercise. Using those tools, you may find that you need to apply lots of power to achieve your desired spl levels, perhaps more than the Polks were designed to handle. Or, you could find that you are using less power than expected, in which case using a more powerful amp may be a potential solution. I really can't say from this end, as I don't know if you damaged your speakers from having too much amp (doubtful with an AVR) or too little. I hope that these posts will help you determine the limits of your system in your room so you can decide accordingly.

In you first post you mention you like it loud. This is much more easily accomplished with higher sensitivity speakers than applying brute force to less sensitive speakers.

 

[Goliath]

Hi sky,

The RTI-A9's have a 90 dB sensitivity while the RTI-A3 has a 89 dB sensitivity. The RTI-A9 is a MUCH larger speaker with 3 x 7" woofers per speaker. So it has much more firepower. My question is, if the same tweeter was used, does that mean the tweeters power handling is the same? I see the power handling for the speaker is much higher than the RTI-A3.

 

[ski2xblack]

That's not really surprising, considering the bulk of the power goes to frequencies handled by the woofs. More importantly, the sensitivity is nearly identical. 1 Db is the standard of "just barely noticeable" difference, and reflects negligible difference in amp power. Because the big ones can take more, I would expect them to get a tad bit louder...remember, doubling power only raises spl by 3 db...and with more robust bass response. That may make all the difference in your system, but you may still be running in the red so to speak. I too would be worried about frying another tweeter, so my first priority would be to pick speakers/amps so that such an outcome is unlikely.

Just for the sake of comparison, compared to the Polks, the Cornwalls you inquired about in another thread would easily create rock festival level volumes, and do it rather cleanly, with far less risk of speaker damage, given the same power you feed the Polks.

edit: sorry, that wasn't you that asked about the old Klipsch, but still, as a counter example to what you use, it hopefully sheds light on your situation.

 

[TLS Guy]

Hi everyone,

Today I was playing some music at quite a loud level, not sure what the dB reading was, but it was loud. I have Polk RTI-A3 speakers and an Onkyo 515. It is 130 watts 6 ohms. I heard a weird sound coming from the tweeter, it sounded like heavy distortion and I turned it down. Problem is that distorted sound is still there, no matter the source.

My question is, how would I improve volume and prevent this from happening again? Buy a speaker with a better handling capability or a bigger amp? I could turn the volume down but I like my music loud.

I suspect you listen to highly compressed pop and rock at high volumes.

Now you need to listen. Now the tweeter, next the hair cells in you inner ear. There are no replacements for those.

The vast majority of domestic speakers talked about on these forums are not designed as high power reproducers.

Pro speakers have high sensitivity and pay a severe penalty in accuracy.

To produce a fine accurate speaker that also has high power handling is a very expensive proposition indeed. They also require active electronic crossovers, as least below about 2.5 kHz and you need a huge amount of amp power.

Classical music and rock are very different animals. Although classical music has some huge crescendos, most of it, about 90%, is relatively quiet, so the drivers and above all your ears get a break.

My advice is to turn it down.

If you want to persist be prepared to spend an awful lot of money and also begin selecting your hearing aids.

 

[ski2xblack]

TLS is correct. Good and Loud is not cheap. And once your system is not the limiting factor, your hearing becomes so. Treat your hearing with care, as you cannot undo the damage once inflicted.

That being said, I suspect your room is big enough, and your speakers are insensitive enough, that your system's limits are still probably below any potentially damaging levels. That's another reason why you need an spl meter, so you can know for certain.

Since you're obviously the inquisitive type, I would suggest these essentials for any audio nut:
-Toole's book on acoustics
-spl meter, or better yet, calibrated mic+REW or an omnimic (this will allow you to contextualize what you learn in Toole's book, as well as being a tremendous tool for calibrating your systems)