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Title: PA HF artefact Post by: Eric on October 02, 2012, 10:46:11 am Peter,
when I start playing with PA engaged, I perceive a very high frequency tone. This tone is very low volume and very high frequency, and it starts about 1 second before the music. After the music has stopped playing, the tone fades out after about 2 seconds. Of course the tone can be heard much better when you put yourself close to the loudspeakers, but once you know how it sounds, you can easily hear it fom the listening position. Is this something you recognise? Or am I the only one? Cheers, Eric Title: Re: PA HF artefact Post by: PeterSt on October 02, 2012, 12:27:43 pm Hi Eric,
When you say "it starts 1 second before the music" are you sure this isn't just the music already, but a silent lead-in of it ? Otherwise, what happens when you set "After SFS Rounds = 1" and have an SFS of something like 60 (not too low in any case) ? Regards, Peter Title: Re: PA HF artefact Post by: Eric on October 02, 2012, 01:32:13 pm Peter,
it could very well be a silent lead-in of the track, I don't know. When I apply "After SFS Round = 1", the start of the artefact has been postponed - but it has not disappeared. It remains there during the play of the track, including the silent lead-out of the track (or whatever happens at the and). As I said, it's volume is at pretty low level, but audible depending on the kind of music. Could this be the price we have to pay for playing with PA engaged? Or can you let it disappear? Cheers Eric Title: Re: PA HF artefact Post by: PeterSt on October 02, 2012, 02:09:17 pm Eric - thanks.
This could be a most sneaky one. Can you still hear it while music starts to play softly (or just plays softly with that SFS Rounds = 1) ? If so, can you point me to a track I might have, and when you don't think so FileMail it to me ? Peter PS: From the NOS1 specs : DC can not be sustained ... This is what might be happening when the music plays softly ... Title: Re: PA HF artefact Post by: Eric on October 02, 2012, 02:31:24 pm Peter,
as an example, take the first track of Pink Floyd - Dark Side Of The Moon. Cheers Eric :15a: Title: Re: PA HF artefact Post by: PeterSt on October 02, 2012, 06:27:49 pm Eric, bad luck for you I'm afraid ...
Let me first tell you that DSOTM is noisy as hell in the original version as well as the "original master recording" I have here, and I don't hear you talk about that. This is just an indication what I hear through my (115dB) speakers. Otherwise ? Nothing. I checked with "silent" recordings as well. But also I recall that I measured it before and no anomaly (at silence) was to be seen. Tip : look at the DC Blocking of your amplifier(s). I have the hunch that you may hear those caps. Not that I have heard about such a thing ever, but I think it can. Good luck ! ... Peter Title: Re: PA HF artefact Post by: Eric on October 02, 2012, 06:56:04 pm Thanks for the tip Peter,
I will ask Bert to take a look at the caps (this was planned anyway). Cheers Eric |