2. speakers
  3. 191863-197398

Burn Twetter Speaker

This is the second time that the tweeter of one of my Rega RX Five speakers, bought used in a physical store, has burned out.



System Specifications:


 
  • Cabinet Construction: 18mm MDF Real wood veneer
  • Cabinet Design: Band pass enclosure
  • Dimensions (cm) H x W x D: 83.5 x 18.2 x 34.2
  • Weight (each): 16.6Kg
  • Reflex Port: Front ported
  • Impedance: Nominal 6Ω
  • Sensitivity: 89 dB
  • Power Handling: 110w per channel
  • High Frequency unit: Rega ZRR
  • Mid /bass driver (Doped cone): Rega DX-125
  • Side Bass Driver: Rega RR 7.8
  • Type: 2.5 way
I'm using (or was using) them with the Rega Brio-R:

Rega Brio-R Power Output:

Input sensitivities for rated output level:
Input 1 (Phono) input sensitivity = 2.1mV at 47KΩ In p a ra lle l w ith 2 2 0p F .
Maximum Input 1 (Phono) input level = 100mV.
Input 2 to 5 (Line) input sensitivity = 210mV at 47K.
Maximum Input 2 to 5 (Line) input level = 10.25V
Power outputs at 230/115V supply voltage:
50Watts RMS both channels driven into the rated load of 8Ω .
58Watts RMS one channel driven into the rated load of 8Ω .
73Watts RMS both channels driven into the rated load of 4Ω .
93Watts RMS one channel driven into the rated load of 4Ω .
Continued high level use into 4Ω may cause the case to exceed 40° C above the ambient
temperature.



I don't understand if this issue is due to a mismatch with the amplifier since the previous tweeter had already been replaced. i also read in a brochure that "The Rega RX Five speakers, with a power handling of 110W per channel and nominal impedance of 6 ohms, seem to be usable with an amplifier ranging from 30W to 500W, according to the instructions"



However, after reading a couple of articles like this one: Gear4Music Blog and Axiom Audio Blog, it seems that the minimum power of my amplifier may be too low to properly support the speakers.



Since I usually listen at high volumes, though never at maximum volume, I'm wondering if the problem might be due to some sort of clipping or excessive overheating of my Brio amplifier, which then damages the tweeter. I also don't understand why the issue only affects the same speaker each time, and not both.



Maybe an amplifier capable of delivering 100/150/200 watts would be more suitable to support the 110W at 6-ohm impedance of my speakers?



I look forward to your kind response
gio_992
toddsyr's avatar
toddsyr
132 posts
 

About 35 years ago I bought my first decent system. I was young, cranked the hell out of it. Turned it all the way up and just a tweak down when the amp red-lined. I went through tweeters in both cabinets. Paid to heave them replaced. Tech was nice enough to explain to me about Square Wave Damage.

On an oscilloscope, a sound wave should look like a wave. When you overdrive the amplifier, the sound wave shows up without curves, but with horizontal and vertical lines. Like a square.

I didn't hear any clipping or distortion when doing the damage but the damage does occur. I have since learned you don't drive a solid state amp at more than 50% of it's power. Now I have 2 amps and less hearing, LOL!

I'm no audio expert by far, but I have not had a problem with speakers since maintaining the 50% rule.

livinon2wheels
102 posts
 

While its possible there may be a component problem in one of the speaker crossovers, it's my opinion that you need a lot more amplifier than you currently have and my guess is you would turn up your current amplifier even more if you could do it and hear clean sound. I am guessing that you probably NEED about 3 db or more headroom available in the amp if not more. 6 db wouldnt be too much to have if you want to ensure those tweeters survive. So in round numbers you have about 75 wpc available to you now with your current amp add 6 db more power and you are at 300 wpc. That would be a good place to start. If you know you are going to play loud having an amplifier that puts out twice the power of the speaker's power rating is not a bad place to start. This gets you close to that place where you are very certainly giving the speaker clean undistorted power. The distortion introduced by overdriving the amplifier creates overtones that almost certainly go up into the supersonic range above 20khz where the speakers are not designed to operate and those overtones are there in sufficient power to cause damage. Having too much clean power very rarely ever destroys a speaker under any kind of normal usage. Too little power kills tweeters with regularity...ask me how I know. Back in the day I had a 40 wpc dynaco amp SCA80Q that regularly blew tweeters in my larger Advent speakers. When I upgraded to a hafler DH-200 with a 115 wpc my tweeter problems ceased to exist. I think you will have similar results. Good luck and let us know how things turn out. :)

kennyc
1,553 posts
 

+1 likely underpowered amps overdriven to clipping, therefore need more power OR lower volume to non-clipping level.  Much less  likely - tweeters not engineered well enough for longevity.

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