Accidentally ran my dac wide open into amp -- could I have damaged my speakers?

[Rischa]

Evening, all. I had the bright idea to use my RME adi-2 as a preamp into my Denon PMA-1700NE (through the external pre-in). Unfortunately I pressed play forgetting that the dac volume was set to 0 dB and the ref level to 7 dbu, and my speakers got hit with all that wattage for about 5 seconds before I could turn it down (of course in my panic I tried turning down the amps volume first, forgetting I had bypassed it). My speakers are Ascend Acoustics Sierra LXs, so I know they can generally handle the max watts the Denon could have been pumping out, but could the fact that it was so sudden have caused any damage? After testing out a few albums it seems like everything is sounding ok, but I know better than to trust my ears 100% on this sort of thing. Thanks in advance for your input.

 

[Sokel]

I assume it was music that played back, right?
I such case there's no way all amp's power came into life and probably your speakers are fine playing for such a short period.

(lesson learned I hope)

 

[Mikig]

happened to me too with a preamp, changing input or output something brought it to maximum volume. The speakers still sound good, normally if something physical happens to the drivers, you would hear it.

 

[Rischa]

I assume it was music that played back, right?
I such case there's no way all amp's power came into life and probably your speakers are fine playing for such a short period.

(lesson learned I hope)

Yes, music. And lesson learned is always my attitude toward this sort of mistake. Hopefully they're not expensive lessons, though! Appreciate the response.

 

[wwenze]

happened to me too with a preamp, changing input or output something brought it to maximum volume. The speakers still sound good, normally if something physical happens to the drivers, you would hear it.

Minor damages are often inaudible but show up with measurements. Even a phone spectrum app works for this task to check if both speakers perform identical.

 

[Rischa]

Minor damages are often inaudible but show up with measurements. Even a phone spectrum app works for this task to check if both speakers perform identical.

I have an app called spectroid on my phone if that would work. What would I look for in the spectrum?

Spectroid: https://play.google.com/store/apps/details?id=org.intoorbit.spectrum

 

[Chrispy]

Most likely if it sounds fine later on, it is fine. Curious, why use an integrated amp as if it is a power amp?

 

[wwenze]

I have an app called spectroid on my phone if that would work. What would I look for in the spectrum?

Spectroid: https://play.google.com/store/apps/details?id=org.intoorbit.spectrum

I use spectroid too. Kept it after testing a few from Play Store.

Since the phone mic is not calibrated, the actual shape of the FR is not as important (although phone mics today can be quite accurate). But if you see the shape from two speakers are different from each other, then one of them is damaged.

 

[Rischa]

I use spectroid too. Kept it after testing a few from Play Store.

Since the phone mic is not calibrated, the actual shape of the FR is not as important (although phone mics today can be quite accurate). But if you see the shape from two speakers are different from each other, then one of them is damaged.

That's great, thanks for the tip. I'll give it a try later tonight

 

[LTig]

I use spectroid too. Kept it after testing a few from Play Store.

Since the phone mic is not calibrated, the actual shape of the FR is not as important (although phone mics today can be quite accurate). But if you see the shape from two speakers are different from each other, then one of them is damaged.

...or the difference is due to the speakers not being in the exact same spot.

 

[wwenze]

...or the difference is due to the speakers not being in the exact same spot.

That's why close mic should be used

EDIT: Then again if your listening position shows L/R channel differences higher than what is accepted as normal variation between measurers, that's another problem that needs to be fixed isn't it.

 

[JIW]

According to the manufacturer specifications, the input sensitivity is 0.85 V RMS which is 20*log10(0.85) - 10*log10(0.6) = 0.81 dBu. Thus, the input may have been 6.19 dB higher than at which the amps produce maximum power. This would lead to heavy clipping and thus produce a lot of strong high frequency components stressing the tweeters in particular. While the speakers may be able to handle a lot of power, that it only for unclipped signals.

To check if the speakers are still okay, you can run a slow frequency sweep at a moderately high level and listen for any buzzing or rattling. If there is none, they may well be okay.

To avoid such incidents going forward, you can set the RME's reference level to -5 dBu and only if you need more output than available at 0 dB increase it to 1 dBu.

 

[dualazmak]

Just for your possible reference and interest, this morning I shared my "counter measures" in my post here #63 on the thread entitled "Never damaged a speaker...".