Hello Outlaws, I need your help. I am a bachelor this weekend, and--oops--I guess I got a little too exerberant (actually waaaaay tooooo exerberant) with my volume, it appears! I think I "blew" my center channel, whatever blew/blown actually means. I have NHT M6's for center, left, and right (not run full range as I have subwoofers too) run by a 990 and powered by a 7700 for center (as well as 4 surrounds and zone 2) and two 2200 monoblocks for the left and right.

In any event, I seem to have lost the high end on the center channel as it is now muffled--but the dual woofers and midrange are still moving (I couldn't tell about the tweeter). I thought it might be the tweeter, so I put on my "tool time" hat and switched out my right and center tweeters leaving the actual speakers and setup intact. Unfortunately, after I did that, BOTH the center and right channels were muffled. Therefore, I switched the tweeters back and the right channel highs reappeared, but the center channel highs were still a bust. So, it appears, more is wrong with the center speaker than just the tweeter. Is there separate "coils" or other "driver" components that I can visually check to see if they are damaged? I really am at a loss and wonder if I need to just buy one new M6, which is going to be difficult as they stopped production last year and I doubt people that have them are going to want to part with just one and not multiples!

PLEASE HELP. Also, I want to try to fix/replace before my wife gets home on Thursday, so she won't be the wiser about my volume inadequacies and desire to compensate with high volume!

On a related note, how does a 200 watt amplifier blow/damage a speaker rated at 250 watts RMS, with 400 watts peak, and 200 watts recommended? Also, what volume setting on the 990 is safe in case I want to turn it up again?

Thanks in advance!

Ed.

Ed,

It appears that you have damaged both the tweeter and the crossover network. You may be able to purchase new components from the shop where you bought the speakers.

If you must resort to purchasing a used speaker to recover components, you might check Audiogon and eBay. However, my quick search did not reveal any currently for sale.

A speaker rated at 200 W RMS will have a tweeter that is capable of handling about 40 W RMS. However, an amplifier driven into hard clipping will deliver power quite a bit above its rating and most of this will be high frequency distortion. This, with a 200 W RMS amp, may deliver upwards of 300 watts to the tweeter. Tests of the 7700 (and 7500) indicate that Outlaw was quite conservative on the power ratings.

My advice is just to fess up, move another speaker from somewhere into center, and search for parts/replacement.

The power delivered to the speakers depends on the dB level set on the volume of the 990, the individual channel calibrations set in the 990, and the source material. However, if you're getting into the positive numbers that's usually a pretty good sign that you're approaching reasonable limits. The system will start to sound "loud" as harmonic distortion begins to increase at the onset of clipping.

Steve

Sounds like your amp or preamp may have taken a hit to the center channel as well. I'd suggest changing out the center and right preamp outs to the amp, which should tell you if your problem is the 990 or the 7700.

Steve and Greg, thanks for the input. As for Greg's comment about potential problems with the center channel and amp, I was worried about that too; and I even thought at one poibt that is what happened. Therefore, to confirm, I switched some connections to try to isolate any center or amp problems--which seems simple in concept but is actually quite confusing when you are not quite sure what the problem is but still trying to predict "if I do this, this sould/should not happen", especially when you are only a hobbiest and not totally confident your assumptions are correct!). I also switched between stereo and upsample and switched connections again. And, finally, after I switched the tweeters back to where they belonged, I swapped my right and center speakers, and switched connections and between stereo and upsample again. Based on this, I am pretty confident that all the 7700 channels, the 990 channels, and other speakers are fine, but the high end on one speaker (now on the right) is gone with probable tweeter AND cross-over damage as suggested by Steve.

I guess I am going to send the speaker back to NHT for repairs. In the meantime, I don't have a replacement speaker so I will keep the right speaker vacant as TV relies heavily on the center channel, and upsampling to my surrounds fills in the gap adequately for the time being.

If anyone else has any suggestions or diagnosis tecniques, I welcome them, especially on a good CD/DVD to help absolutely confirm all my other speakers are fine.

Thanks again. Ed

You might want to try a setup/calabration disc that gives you frequency sweeps for each channel.
I use the "Avia Guide to Home Theater" DVD for this sort of thing, but there are several available.

It's not hard to repair a crossover. Locate it in the speaker cabinet and see if any capacitors are blown. If so find the same size on line buy it and solder it in!

While your speaker is out being repaired you can adjust the 990 to give you a phantom center channel which will probably sound better than a missing right speaker. Since your speakers are back to original setup with the original tweeters, try swapping the whole right and center speaker. If the problem moves to the right speaker then it is a speaker problem. If not it is an input problem. It is also possible you damaged more than one speaker so you might want to try the left speaker as the center.

It is also possible you damaged the amp.(less likely by far) I had a channel on my 7125 die a while back and just swapped out to a spare channel for a while until I sent it back to Outlaw for some TLC. In the future, you may want to consider an inline fuse with your positive connection. I use a 1 amp sloblo fuse. It will pass about 60 watts to my old Advents so I don't blow them as they are connected to my 7500 for now. This way, when the fuse blows, it protects the speakers from too much exuberance.