HELP blown speakers


Here is my situation. I am using a set of Silverline Sonata Mk 1 speakers with Pass Aleph 2 amps and a Pass Aleph P preamp for the monitoring in my home recording studio. The Aleph P is fed from a MOTU 2408 Mk 3 Audio interface/sound card that is in turn fed by a Power Mac G4. I run all my signals through a single set of stereo outs on the 2408. All the mixing is done via software in the computer (no mixing board)The effects (reverb etc...) that the computer can generate can go from smooth and lush to downright hashy digital grungefest.

I was working on a piece of music yesterday and using an effect that can tend to produce some peaky loud transients at certain moments. Never would I say the volume exceeded 95 db. I do know that more than once I'm sure the output of the 2408 was overdriven. I was noticing that the sound had a definite distorted quality about it, but I thought that it might have something to do with the effect I was using. I started to try and figure out what was causing this and I ended my search at the speakers. It seems that both speakers have suffered damage. I confirmed this by hooking up another set of speakers, which sound fine. The sonata speakers have 2 tweeters each, and it seems that on both speakers they are damaged. The produce sound, but it is definately distorted, I don't think that the midrange and woofer is damaged, though I'm not entirely certain.

What would cause this? I didn't have the preamp volume to high, and I never played the speakers that loud. I'm pretty sure that I have caused major damage to the speakers. I'm sure I can replace the drivers, but I want to make sure this doesn't happen again. Is it possible to overdrive an input on a preamp to the point where it can damage the drivers even though the preamp is not feeding the amps that high of a signal?
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Showing 1 response by jcbtubes

I side with Mech and others on this. A relatively inexpensive audio card can produce unhealthy ultrasonic garbage, whether during clipping or simply as a byproduct of a poor digital filter. It can further cause oscillation or instability in wide-bandwidth amplification stages, like many ss electronics. Whether additional equipment instability occurs or not, this ultrasonic junk will slowly cook your tweeter and/or high-pass x-over components.

Also, don't assume that because a circuit uses tubes that it is limited enough in bandwidth to help in your situation. A good tube pre-amp or buffer stage can easily be flat to 30kHz, and some much higher. If the problem is with sample rate spiking or distortion products within its passband, they will easily be passed downstream to the next component. Mech's suggested solution is sounding better and better. Good luck.