RF-7 Tweets in movies

[AeroTEK]

I have been running RF-7's on a Denon 3803 for about a month now. And one thing I've noticed is that they do bring out the true sound of a recording. There are some DVD's with older sound that drive me nuts like "Patton". Recently though I have noticed that at higher volumes > -20db it seems that the tweets make a faint and rapid sound primarily in talking scenes that lack much backgroud noise. Music sounds great and video games as well (I am pretty sure). I don't notice it except in movies. A few days ago I put in a cd w/ a lot more bass than I usually do and had it at high volume and while I was out of the room it clicked off and went into protective mode. When I checked the reciever it was hot as hell and before I didn't think it much mattered in the area it was , er well so a friend assured me. I figured that all that extra bass probably caused the reciever to work more and produce more heat and forced it to shut off. Well now the receiver is out in the open and I am going to get a new open air audio rack for it eventually. Anyways back to where I was going with this... Before bad audio was always noticeable but recently I have noticed the faint repetative noises on the tweets in quite parts of movies at times. And in the same scenes that have that noise it always is there. I alread rehooked my speaker wire, am using 14 gauge proflex. I even tested the scenes on xbox ps2 and sony dvd player with digital and analog and the sounds are still there. Is it possible that my tweets could be hurt or may it eventually work its way out of the speaker? I have heard these take several hundred hours to break in, but I wonder if there is any truth to that.

Any info would be greatly appreciated.

Thanks

[JewishAMerPrince]

I would check all your connections on the back of the 3803 to be sure you don't have a stray strand or two of speaker wire that is shorted to another. The 3803 shouldn't really break a sweat with the RF7's. Till recently I had a 3801 (nearly identical amps) with my 7's and even at ear splitting levels in a huge (I mean really huge) listening room it never shut down.

As for the faint sounds, be sure that you haven't rum your speaker wires too parallel..this will cause an inductive signal crossover that could create the sounds you describe. The 7's are super efficient and will actually reproduce such minor interference. I use twisted quad 12 ga (bi-wired) just to prevent that very problem.

Jerry Rappaport

[WMcD]

My guess is that this is not an issue of partial speaker distruction.

When that happens it can be basically mechanical. The voice coil gets warped or partially distroyed from heat. The audible result is distortion on all programs.

You seem to describe that the odd sound occurs at the same point in the given recorded movie, all the time. I'll assume that it does not occur in similar situations on other movies. That points to something in the recording itself or how the decoder handles the information.

In my view, this also points away from an amp heating situation or a stray wire.

It may be that the very revealing, accurate, nature of the speaker is allowing you to hear it.

I had a problem with VHS-HiFi movies when they first came out. They would sometimes have a purring effect during quiet passages, similar to the sound of a happy cat. You wouldn't hear it on little old TV internal speakers. Yet with larger, full range speakers it was plainly audible. There was something hinky about the recording or how it was decoded.

The VHS-HiFi is now the standard. The sound is recorded on an frequency modulated track instead of a "classic" strip along the side of the tape. That is to say, there is a more sophisticated play back system which, evidently, can be prone to produce artifacts. It may be the same with DVD, etc., using a digital system with data reduction techniques, etc.

Gil

[AeroTEK]

I checked all the connections and reconnected them however I will go back and check the denon to see if any wires came off stray as I am not using banana plugs. I might try them though. On the speakers I connected the wires negative and positive at opposing ends with the bridge wires conncected. I was told by my dealer it didn't matter where they were connected as long as that wire was left in. I myself wouldn't be supprised if it isn't the audio recordings and I didn't notice that as much when I first started listening to the speakers. After all the movies I initially put in were not so talky talky... Oh and yes the slight distortion repeats on the same points of multiple movies. I almost wonder if I shouldn't get better sheilded speaker wire. Because oddly enough before I reconnected the wires I would hear the radio on my speakers when I had the volume turned way up on other inputs DVD, VCR1 etc. when those components were turned off. Any Recommendations on wire that won't cost hundreds of dollars?

Thanks

Joe

[JohnA]

You SURE don't need shielded speaker cables.

I'll bet the resolution capability of your RF-7s are so much greater than what you've had before you are now hearing a "pumping" caused by processing the signal from old analog masters through a noise gate. It's done to try to hide the background hiss inherent in the source, but it's often well below perfection. That it occurs in the same places in old movies tends to prove this theory.

[avman]

you may also want to set all digital inputs to the type of digital connection you are using,vs.'auto'. this will help prevent 'cross-talk' from the pre-amp in your receiver.if you are NOT using an input that has a digital input available,optical digital in particular, select 'optical' as the input for those unused inputs. i'm not sure if your brand of receiver has those options, but it lowered the noise floor on mine.

av.

[BBB]

VERY good point avman.Eliminate all possibilities for crosstalk interference with your setups. That's an idea that might help plenty of people here who haven't thought to do that yet with their receivers.

[Deang]

Good suggestions by everyone, and a couple of things in this thread I never knew.

You really didn't do a very good job of describing the sound -- you only said what it is doing. What kind of repetitive noise? Clicking, ticking, ringing, crackling -- what does it actually sound like? Are you 100% sure it's the tweeter?