Those results sound typical. It seems the common denominator in all these is that the noise is higher when the pre/pro is converting an analog signal to digital, and back to analog. Mine is the same. This _should not_ be the case, if the onboard converters are anywhere near the advertised resolution of '24 bits'. Again, I can digitize and convert back to analog on my digital audio workstation _and_ do a bunch of DSP processing (more than the 950 will ever hope to do) and the result is dead silent. The 'actual' real-world resolution of my workstation is around 20 bits.

I have mentioned this before, but it bears repeating: line noise generally has _nothing_ to do with steady state elevated noise floor. Keep in mind that there is AC line filtering onboard almost all components, and the power supply in all devices filter out the remaining 'line noise', outputting DC for the circuits inside. On top of that, there is local de-coupling near the power input pins of almost all ICs inside the unit. If there is anything that gets through, is is generally things like buzzes, pops, clicks - but not steady state hiss. Also, most "power line conditioners" have nothing more than metal oxide varistors inside them, and their _only_ purpose is to protect against gross overvoltage, for example from a lighting strike. If you want an actual power line _filter_, units like the TrippLite "IsoBar" series are excellent.

[This message has been edited by soundhound (edited November 06, 2002).]

Yes but that is what most hiss in the 950 has been exactly described at: and thus not really useful.
Hiss at a few inches or foot out at un-realistic gain. (+10)
With no hiss/ or some hiss only at ‘the ear at fabric’ tweeter distance when at usable gain.

And whether or not This _should not_ be the case it does appear to be in various forms and configurations a common denominator in many units produced by other Companys.

I'm not concerned with those cases personally because they IMO are unrealistic. What does concern me are the reports of 950 hiss audible out to several feet at or near useful listening volumes.

Those cases should basically never happen in any reasonable system.

EDIT:

Also, keep in mind that on a prepro like the 950 +10 may be a useful gain setting if it's been properly setup such that '0' is 105 db.


[This message has been edited by charlie (edited November 06, 2002).]

Lena- Most of the comments on the 950's hiss are useful and meaningful. In a lot of cases, people are directly comparing the hiss in the 950 to a previous component too.

The hiss in my 950 is volume independent. Don't matter none if I have the volume set at +10 dB or -50 dB.

The hiss from all of my speakers is evident out to about 2 feet. I do not have to put my ear up against the tweeter and turn my head just so to hear it. For my rear center, the distance is 4 ft. That impedes into my listening position.

Others have posted than at normal listening volumes, they can hear hiss out to 10 - 12 ft. That is probably more rare, but I've personally never heard of any other component (except for a malfunctioning one) where the hiss was that bad.


[This message has been edited by Kevin C Brown (edited November 06, 2002).]

Lena, nobody here is complaining about hiss from a few inches or at an unrealistic gain.

Here is an example:

I have a 1050 and when I play a movie back at '60' (80 is wide open) I get peaks a bit over 105 db. Now a few seconds of reflection inform me that:

1 - This is pretty damn loud.
2 - A few more db and I'll be into clipping.
3 - Taking 1&2 together I conclude that somewhere around 65 or 70 is all the useful gain I have.

At 65 the system is dead silent with any source, analog or digital selected. This is admirable but not really a requirement - a bit of noise would be OK.

At 80 it's silent too, but that's not the point. When I had a 'big amp' on the mains a bit of noise was present at this setting, audible to about 1 - 2 inches. Also note that this would result in peak output around 135 db if all the parts were capable. In reality I would get amp clipping somewhere around 1Kw/channel followed shortly by speaker destruction and PSH.

At usable volumes with the external amp 1050 noise was essentially zero.

This topic is perhaps more appropriate for the "hissy-fit" forum.

Be that as it may, here are my observations on hiss:

1. A quality audio system with no input should exhibit no audible hiss at even less-than-normal listening distance (I will arbitrarily define as 6 feet). If it does, the problem is with the system and most likely the amplifier(s). My normal listening distance is about 20 feet and the remaining comments are based on that distance. I do not hear ANY hiss from my system in no-actual-input mode at that distance from any source EXCEPT the 950. At my normal listening distance, the hiss from the 950 is detectable but very low. I should perhaps also say that while I do not have "perfect pitch", etc. etc. my hearing is tested every year as part of the physical demanded by my employer and it happens that it is excellent i.e. quite sensitive [despite the abuse from loud music during my wild and crazy twenties!].

2. Beyond that, the expected / acceptable hiss depends upon the quality of the source. I still listen to much vinyl, and hiss / surface noise exceeds what I hear on my 950 - by a lot for some recordings, not by much for a few, and by very little for my best. Hiss from my tuner seems to depend on the quality of the station source and from most but not all stations is below that from the 950 on movie inputs; from the best stations is almost (not quite) inaudible. Hiss from CDs OR DVDs when played through my analog stereo system is totally inaudible even from less-than-normal listening distances (in many ways their only saving grace, pardon the preaching), and this is what I would have expected from a digital source had I not read the many posts before ordering.

3. So my standard digital audio source - CDs - is notable for lack of hiss/noise. The HT experenience through dolby / dts / etc. is not. Is it a problem with pre/pros? A problem with home theater / dolby / dts / etc? A problem with signal complexity? Bottom line: I listend to cheaper units, I listend to expensive units, I listened to outrageous units. The level of hiss varied - generally on a curve related to price - but in no case reached zero at normal listening levels.

SLL - for more "hisssy interesting reads" check out the PS Audio Power forum and the general forum at Audio Aslymn(sp). By the way, luck you, when I interjected the same obdervations last month, this forum ripped me a new one. How dare I try and "downplay" an obvious QC problem in Malaysia Yada yada.

Its nice to know there are some who belive interjecting this is reasonable/and offer for our reading pleasure.

I have been in audio for a very long time, and I have seen a 'dumbing down' in quality which I think started about the time home theatre came into being. You may or may not have heard of or had experience with names like Mcintosh, Marantz, Fisher, Scott etc, when they were quality companies, before they were bought up by Enron Anyway, it used to be that conponents routinely _exceeded_ their published specifications, and the name badge on the front of the unit was the name of the man who founded the company.

Things have changed.

Blame it on the computer business. Obsolenence is expected in mere months. Product problems are 'fixed' by "updates", sometimes at user cost. Marketers play fast and loose with specification claims. NOTHING is meant to last long enough to hand down to your kids.

More to the point of your original question, I think that it is a combination of marketers wanting to make things inexpensive enough to sell to the 'masses', lack of knowledge on the part of the current generation of designers as to what consitiutes solid performance, and a mentality of lack of personal responsibility for a product. Mix these with buzz words like 24 bit/96Khz "perfect sound forever" etc, and you end up with what you see today.

The 950, or ANY other digital component should NOT hiss from more than inches from the speaker at normal listening levels. It CAN be done. My digital audio workstation (24 bit) IS dead quiet even with my ear at the tweeter, when playing a track which only has dither at the 24th bit level, and that's with _any_ amount of DSP thrown in the loop. As to why the current generation of home theatre equipment can't do this, apparently at ANY cost is a mystery.

Maybe it's just that there aren't enough people out there who EXPECT solid performance, maybe they've all died off. Who knows?

[This message has been edited by soundhound (edited November 06, 2002).]

I have NEVER seen anybody bad-mouthing you in these forums. You might be mis-intrepreting the differing views by other members of this forum as some kind of personal attack. This is NOT the case. Personally, I'm very glad to hear your opinions, and they are just as valid as mine, or any body else's.