Tracking down distortion?

[PaulB]

I have a suspicion that my new 412's have a problem... Very occasionally and unpredictably I hear a very very subtle transient "crackle" in the upper mid range on one speaker. I can't decide if it's a poor recording (I've noticed it mainly on a few older A to D releases and some very small label releases) but I'm skeptical since it's always the right speaker. It sounds almost like a dirty connector or pot (but isn't). I'm pretty adept technically but I've never dealt with anything like this. Where would you guys start to figure out if there is a problem and narrow down the cause? I'm especially concerned since these are no longer available and the thought of shipping it for repair is pretty horrifying. Thanks in advance...

(You sure you want to keep those dirty old 4343s Steve?) :biting:

PaulB

[Mike Caldwell]

First off I would try swapping the speakers left for right and see if the problem moves with the speaker. If it does it's in the speaker cabinet it self. If the problem does not move it somewhere before the speaker.

Mike Caldwell

[PaulB]

I'm planning to try that Mike, but the problem is so sporadic I'm hoping I can reproduce it by remembering what track I was listening to at the time. Think I may bring home my sweep gen and try to find the "sweet" spot.

[Mike Caldwell]

You beat me to my next suggestion of trying a test tone generator or a CD with tones on it.

Mike Caldwell

[invstbiker]

(You sure you want to keep those dirty old 4343s Steve?) :biting:

PaulB

Paul, just did a CSN concert on the Paul B's, now biamped, dude, fly out to PHX, (I'll pick-U-Up) and we'll party. Anytime after Labor day, I gotta go to work in SD....

[PaulB]

Thanks for the offer Steve. Ya think they'll let me bring them back as carry on? ;)
I just stumbled over the thread about your bass issues, wish you'd have called me. Glad it worked out though...

PaulB

[PaulB]

OK... I've been on the trail of my "distortion".

I have figured out this: it actually seems to be in both channels (my right ear is slightly better so I think it picked it up more readily). It seems to be the UHF driver. Seems to be very specific frequencies or combinations. 99.99% of the time the 412s are really outstanding. Actually I think I'm picking up some sounds due to them being brighter and perhaps more efficient than my 4343s were (RIP) that I hadn't heard previously and I'm wondering if this is what I'm really hearing.
I have used both my CD player in the CD input, as well as my DVD player in it's input with the same results. The best comparison I can make that may be readily available is on Miles Davis' "Kind of Blue", the opening track ("So What") there's a very faint crackle in the first few notes he blows. I know this is inherent in the recording (at least my copy) because I can hear it on three different systems I've owned. I hear the same thing but much fainter on my new system...very occasionally. Things like sibilance on vocals (again...not always) have a tinyyyyyyy crackle. I can repeat it on (here's an esoteric recording) Ute Lemper's "All that Jazz", track 3 opens with some very faint "effects", almost like sonar sounds...they have the mystery crackle. It seems unlikely that both speakers have the identical defect so what am I hearing? Some bizarre receiver issue? (Brand new AVR 7300 direct from HK). Just hearing minute details on recordings that I haven't noticed before? Losing my sanity?

SOS...SOS...SOS...

[PaulB]

This has been driving me nuts. But I think I found the answer. It's (at least in the case of the Ute Lemper recording which is the only one I can positively reproduce the crackle) in the recodring. I don't have another system that can reproduce the freqs in question so I loaded the CD in my PC and opened it in Sound Forge and expanded the waveform at that point and sure enough, there's the "crackle". Why the hell it's there baffles me but it is. I assume I'd find the same thing on any other passage where I hear the sound. What's baffling is why I never heard it on a much better system before. Speaker placement? Whatever it is, at least I know I'm not losing my sanity (or ears)...

[invstbiker]

Your're not losin' it, you're just particular. at our age perfection is in, back then who cared, now, totally different. I "pulled my (whats left of it) hair out, trying to find my bass. Well, I've got it now, thx to this forum!! Help me out, 'caus I can't remember....Tommy, The Who. HS teacher was in to this, name?? Well, it's on now, 4343's and WOW, great stuff, after a few brewskis and a eh hem...that's a good story...:D