Question about hiss from Sony STR-DA4ES...owners please help! (1 Viewer)

[Greg Schwabacher]

I posted this question over on AVS Forum, but haven't had any luck with answers. I mentioned it in another thread here, too, but no luck there either, so here goes:

I just got my new receiver this past weekend, and I have noticed a fair amount of hiss through the speakers at high volumes with using a DSP mode (like dts:neo-6 or DPL-II) with an analog-only input or when an input is forced to analog mode. For example, if I set the receiver to the TAPE input, it's dead quiet (unless I crank it to -10 dB or higher, when I can hear just a bit of analog noise). However, if I turn DPL-II or something similar on at this high volume setting, then the hiss volume rises substantially. Of course, this is at very high volumes and isn't generally noticable in normal listening -- there hasn't been a source playing when I noticed the hiss. Plus, it's easily avoided, because I don't hear any additional noise when using DSP modes with a digital signal!

What I'm wondering is if this is normal. All of my older Sony receivers (STR-DA50ES and STR-D915) exhibit similar behavior, so I think it's just the nature of the beast. Still, my mind is on it now, and I probably will never use DPL-II or similar processing modes with analog-only sources.

If you own a 'DA4ES, please check for this hiss before you reply and say you can't hear it...it's something you wouldn't likely notice unless specifically checking for it, as I doubt many people frequently applying DPL-II or similar algorithms to non-digital sources.

 

[Seth_L]

My DA5 is just as quiet (maybe quieter) in DPL II as it is in analog mode. It's not audible until about -15dB on the volume scale.

Seth

 

[Greg Schwabacher]

Seth-
Did you engage DPL-II on a non-active ANALOG ONLY input (like the tape input)? My 'DA4ES is waaaaay louder with DPL-II engaged on an analog input than in analog direct mode. Digital inputs are another matter altogether -- very, very quiet regardless of sound field.
I just got finished comparing the DSP/analog noise (using my Rat Shack SPL meter) from my old 'DA50ES to the noise from my 'DA4ES and they both are very, very comparable at max volume. I have to believe that my 'DA4ES is performing properly based on my measurements and based on another user's observations here.
Thanks for the response, though!! Anyone else care to weigh in?

 

[Seth_L]

Greg,

Yes, I tried it on a non-active Analog only input. The Digital inputs should be completely silent because the amps are turned off unless there is a signal with some amplitude present.

Seth

 

[Greg Schwabacher]

Seth, when I checked the digital inputs, I made sure that I played back a digital signal with a very low amplitude signal so that the amps wouldn't be muted...that's how I was able to verify that the hiss was lower in digital mode. Thanks for the follow-up, though.

 

[TonyTone]

Just waking this post up since I'm experiencing something familiar to what Greg is describing--basically, when I crank the volume anywhere higher than -20 dB on my DA4ES when on any input (e.g., SAT, VCR, TAPE, CD) except DVD, I can clearly hear hiss from my speakers at 3 feet (and probably even at a greater distance). At levels higher than -10 dB the hiss is unmistakable. At no time during this "test" was any of the connected equipment powered on.

I'm also puzzled that the CD/SACD input (I have a very old Sony 10-disc CD changer--remember the 10-disc magazine?-- connected to it) is generating hiss even though the changer (again, not powered on) is connected to the receiver via optical, while OTOH there is no hiss from the DVD input even though the DVD player is connected to the DVD input via digital coax regardless of whether or not it is powered on. I didn't do any thorough testing beyond what I just described; I'll swap cables between the CD and DVD (and try different digital inputs) tonight to see if I can eliminate the cable or input as culprits. I would have thought that if there would be any hiss from the digital inputs, it would have been equipment connected via coax...

In any case, is what I described above (either one) typical? Please forgive me if this has been discussed already, but I'm still new to the technical aspects of what to expect when setting up a HT system.

Thanks!

 

[Alex F.]

Regarding a Sony 5ES that I purchased last week: Yesterday I pulled it out of our den and will return it to the store. The biggest problem was hiss.

The unit was intended for occasional surround-sound use in our den system. My plan was to use the 5ES's rear-channel amps (and free up an Adcom 5400 power amp for another room) and to use the front-channel preamp outputs to feed our McIntosh 6500 integrated amp, which drives the mains.

I tested the 5ES's preamp outputs only (using the Mac and Adcom power amps). Unfortunately, on all inputs and in any mode--digital and analog, and stereo, DD, DSP, etc.--the hiss became intrusive at the listening seat 8-feet away when the Sony volume readout was at about -15 db or above. In combination with the Mac at unity gain and Polk's LSi-25 loudspeakers, this translates to a typical, enjoyable level (loud but not too much so) for DVD movies; PLII-enhanced and DSP-enhanced CD music; and stereo and PLII VCR audio.

I am very disappointed in the 5ES's preamp section. The sonics, too, were below expectation--not as smooth as I had hoped for and a bit hard and edgy in the upper midrange area. I ran the 5ES for several days hoping it would break-in and become smoother and cleaner, but it did not.

I first became aware of the hiss while playing a familiar Strauss waltz CD (via a Sony 7000 DVD player's coaxial digital output). With the disc not playing, there was silence, as would be expected when no digital signal is present. But when the CD began playing, well, it was a veritable hiss concert.

For the time being I went back to our Denon AVP-8000, which was expecting a home in our upcoming theater room. The Denon's sonics are far superior--much smoother, and it has a relaxed, easy-going liquidity throughout the midrange that is completely nonfatiguing yet enormously detailed.

If I don't find a suitable unit for the den, the Denon pre-pro will have to become accustomed to habitating in the den permanently. Of course, then the theater room will need a new pre-pro...

I had expected the 5ES to solve a problem. Instead it became a problem itself.

Back to the drawing board.

Have a nice weekend, everyone!

 

[Greg Schwabacher]

Tony-

What I've noticed is that any time a DSP sound field is applied to an analog input, the hiss is more pronounced. I suspect what you've done is put your receiver in Auto Decode mode. That is, believe it or not, an actual DSP mode, and when feeding this mode via an analog input, you'll notice this hiss. If you switch your receiver to Analog Direct mode or 2 channel stereo (for audio inputs), I bet this hiss disappears.

The workaround I see for this is to simply feed the receiver a digital signal any time you think you'll be doing any sound field processing.

After doing some rough measurements and crude calculations, I figure that the signal-to-noise ratio of the analog inputs when used with active DSP processing is somewhere around 80 dB, give or take. The Analog Direct mode's and digital inputs' S/N ratios are much, much lower.

I'm practically convinced this is typical, at least for Sony receivers. Both my STR-DA50ES and STR-D915 (older Sony receivers) exhibit similar behavior when digital processing is combined with analog inputs.

As far as your DVD player is concerned, maybe it's possible that your receiver is detecting a low-level coaxial digital signal from the DVD player even when it's turned off (does COAX appear on the receiver's display?). The receiver mutes its output on low-level digital signals, so you wouldn't hear hiss if this were the case. You also may have inadvertently engaged Analog Direct mode on the DVD input, or you could have set the input mode for the DVD input to Coaxial instead of to Auto. I bet money if you force the DVD input mode to analog and switch on some type of digital signal processing (DPL-II, DCS, or Auto Decode) you'll hear that hiss.

 

[David S]

"With the disc not playing, there was silence, as would be expected when no digital signal is present. But when the CD began playing, well, it was a veritable hiss concert".

But does not this point to the source (the masters)/the CD itself. I'm not sure I'd point the full blame on the Sony here. My Miles Davis-Kind of Blue SACD has a lot of hiss in the intro to "So What". As the band kicks it up, the music masks the hiss/but it must be still there, no? Just cant hear it in not so soft passages. Press pause, hiss reduced. Between tracks no hiss either. Its just during the tunes. I do not see how the equipment is at fault here. Maybe during pause, preamp mutes something, but there is no hiss between tracks. I've checked, and this seem univeral on KOB, the CD, SACD. I do wonder about the vinyl though.

Same is true on Mingus Ah Um, and Dylan Blond on Blond SACDs. For comparison, I have loads of CDs/other SACDs with no hiss at all. There is just a lot of recorded music out there that carries hiss with it. A lot does not. Thats why if I'm demoing stuff/the CD's are key to me to hear how good a piece can really get. As a result though, a good preamp can make a bad recording sound really bad!

 

[Alex F.]

As I said, it's a CD with which I am familiar. And, no, the hiss is not there when the disc is played through my Denon pre-pro. I checked this just to be sure. The source of the hiss is the Sony 5ES.

 

[TonyTone]

Greg--I'm pretty sure I did the Analog Direct and 2-ch stereo tests on the various inputs (CD, TAPE, SAT), and I still heard hiss when volume knob is cranked past -20 dB. I'll double-check tonight but I'm pretty sure I got hiss when I tested the night before.

As far as the DVD input is concerned--I can't recall if COAX appeared in the display when I selected DVD input on the receiver. I do know that I didn't inadvertantly engage Analog Direct when in DVD mode.

Any of this still doesn't explain why there would be hiss on the CD input when a) CD changer is connected via optical; and b) when I first selected CD input, IIRC the receiver had automatically gone into 2-ch stereo mode since I hadn't selected a DSP mode previously (I believe each input remembers the last DSP mode that was active); also, I most likely hadn't selected any of the various 4/5-channel soundfield modes since the display showed only the L and R speakers as active.

 

[Greg Schwabacher]

You might have gotten a teeny bit of hiss past -20 dB in Analog Direct mode on those inputs, but if you engage a DSP mode with an active analog input, I bet you'll notice a lot more hiss. Let me know!

 

[Greg Schwabacher]

Hey Tony, did you get a chance to re-check this? Personally, I'm most interested in the relative levels of hiss you notice when you have DSP engaged on an analog input and when you don't.

 

[TonyTone]

Okay Greg (and whoever else may be interested in the following)--here are my totally unscientific findings after messing around with the various inputs and decoding on my DA4ES:


Input
DSS (Video1) 3 3 2 RCA
VCR (Video2) 3 3 0 RCA
(Video3)**** 3 3 1 n/a
DVD (DVD/LD) 0 0 1 Coax
PS/2(TV/SAT) 3 3 0 RCA
(TAPE)****** 3 1 1 n/a
(MD) ******* 3 1 1 n/a
CD (CD/SACD) 3 1 1 Optical

Translation of the above table and other stuff:

--Column 1=Input (actual input label in parentheses), Col2=AUTO DEC mode, Col3=2-ch stereo mode, Col4=Analog Direct mode, Col5=Audio cable type--if there is an easier way to properly cut and paste a nicely-formatted table, please tell me how!
--Receiver volume was set at 0 dB unless otherwise noted below
--Any and all attached equipment to the various inputs were powered off
--Listening position was centered between the FL and FR speakers, about 3 feet from each front speaker
--No additional sound field decoding (e.g. Cinema studio, Church, etc.) enabled during testing (sorry Greg--didn't get a chance to test with DSP since I was testing just for hiss in general regardless of any type of decoding)
--The stuff in parentheses refer to the actual input label printed on the back of the 4ES
--The numbers represent relative hiss levels on a scale of 0 to 3, where 3=unmistakable (not extremely loud) hiss, 2=hiss at 1/2 volume intensity (guessing) of 3, 1=very faint hiss (meaning that I can't hear any when volume knob is at -10 dB from same listening position stated above), 0=no hiss
--"n/a" implies no equipment attached to input
--All attached equipment, the TV, and the 4ES itself are connected to a Monster HTS1000 surge protector.
--Of course, when I hit "Mute" during any input, there's no hiss at all!

Greg--the "Audio Input Mode" of the DVD input was initially set to "Coaxial Fixed"; when I changed it to "Auto 2-ch" I was able to hear hiss, so you were right in this regard.

What's puzzling is that although I'm using mid-grade Monster Cable RCA audio interconnects for the DSS (Video1) input and RatShack Gold-series RCA audio interconnects for the VCR (Video2) input, when I enable "Analog Direct" for either input, I get some hiss on the DSS input but none on the VCR input; however, there is a very faint whine on the VCR input in "AD" mode (nowhere near as loud as the hiss detected on the DSS input when it's in "AD" mode though). Since it can't be easily determined as to if the whine heard on the VCR input when it's in "AD" mode is an issue with the RatShack RCA cable or the VCR itself, I'm not gonna bother swapping cables (too much work pulling the AV stand out and yanking cables, you know!). Even if it could be narrowed down to a cable issue, it's still weird that there is no hiss from the RS cable connected to the VCR input in AD mode while there is some hiss from the Monster cable connected to the DSS input when in AD mode.

I apologize if any of the above isn't low-level technical enough for some of you but I feel that the info given above may be enough for someone in this forum to determine if any of it is normal/acceptable for the DA4ES, if not all receivers in general.

Thanks!

 

[Greg Schwabacher]

Tony-

Your findings completely jive with what I've found on my reciever.

Let's look at the second column. Believe it or not, AUTO DECODE is a DSP mode (because it uses the DSP to determine what bass to send the sub). Since we know we're going to get hiss with any DSP mode when applied to an analog input, that explains all the threes in your second column. The lone zero next to DVD in the second column can be explained away because you have an always-active digital coaxial input from your DVD player, and digital signals with low or no amplitude cause the receiver to mute its outputs.

Now, on to your third (2-ch) column. This one is weird, but I've noticed the exact same thing on my 'DA4ES. That is...it seems like, for the 2-CH STEREO mode, the receiver applies DSP processing to the analog video inputs but does NOT apply DSP processing to the analog, audio only inputs. That's why you've recorded threes in column three for all your video inputs but only ones for all your audio-only analog inputs.

Finally, for your fourth column...Analog Direct is generally the most quiet (well, other than digital) on my receiver, and the level of hiss can vary widely depending on the input. My CD input is the quietest...which to me makes sense because this input seems to be on a totally separate circuit from the other inputs. Notice how when you switch in and out of the CD/SACD input you can hear a distinct "click?" That's why I think it's on a different circuit. Also, analog inputs without anything connected to them are louded that those with components connected but powered off. You can make shorting plugs for your analog inputs if this bothers you.

If it makes you feel any better, I can detect very low intensity whines from different analog inputs at different times. I haven't even made any attempt to diagnose these, but since they come and go, I figure they're just noise.

So, we've confirmed that both our receivers perform EXACTLY the same when it comes to hiss. Nice matrix, BTW!! Based on this and threads on other forums, I think our receivers are performing properly.

 

[Greg Schwabacher]

Tony-

One other question for you...what kind of speakers are you using? What's their sensitivity? Man, I wish you had an SPL meter!

All though I'm 99% sure what we're hearing is the nature of the beast, I'm going to try to go to a local store tomorrow or Monday that carries the 'DA4ES and give it a little listen. We'll see...

 

[TonyTone]

Greg--S38 (89dB) and S-CenterII (91dB) up front, S26 (87dB) in back, and a SVS 25-31 PC+. I have an SPL meter but didn't use it during my unscientific test since I was just testing for any audible hiss and how loud it was, depending on input type and audio output (AutoDec, 2-ch, Analog Direct).
Also, do you find that when you turn on the internal 4ES test tone generator and select "Fix", it is sending a low volume (but distinctly audible) test signal to the sub regardless of what speaker you've selected during the test? This low volume signal coming from the sub is distinct from the normal test signal emanating from the sub when you explicitly choose it during the test. Odd, if you ask me...
Lemme know what you find out during your field trip!

 

[Greg Schwabacher]

Wow! My Klipsch speakers are substantially more efficient than your JBL's (98dB front, 97dB center, 95dB surround), which means that at any given volume setting, mine will be that much louder. In other words, at max volume, the hiss is up to 9dB louder!

I think the low volume test signal that the 4ES is sending your sub is a result of the crossover settings you've chosen for each speaker (I noticed it both when the test tone generator was set to "Auto" and "Fixed"). When I set all of my speakers to "Large," the low volume signal you describe disappears, or at least it did on my 4ES.

I probably won't get a chance to go on my "field trip" until tomorrow, and maybe not until next weekend. I'll let you know what I find out, though!!

 

[Kevin C Brown]

Greg- You can try this. Worked on the TA-E9000ES pre/pro, but obviously, that design is miles apart from the receiver (except for the SHARCs!).

If you go into the config, and "set" each physical connection for each source input, that helped the noise level a lot on the pre/pro. In other words, for the DVD input select coax, for the CD input select optical (or whatever).

NOT THE SAME AS AUTO FORMAT DECODE. That's just DSP. This is for the physical connection. On the pre/pro, if you let it "find" the source signal itself, the noise floor was a lot higher. If you "set" each input, was much better.

 

[TonyTone]

Greg--
Yep, the sub test tone bleedthrough occurs regardless of whether the test tone selector is on "Auto" or "Fix". I won't worry about it too much since you said the same thing happens on your 4ES. It is still kind of odd that there is some sub bleedthrough even though you selected a specific speaker to test during the "Fix" test tone setting. Not a good thing IMHO if one were to use the internal test tones to balance the various channels.
Kevin--you're correct; I found the same thing when I was testing for hiss on the DVD input. There is hiss when DVD input is set to "Auto-2ch", but no hiss when set to "Coaxial/Optical Fixed"--except of course when you select "Analog Direct" mode, in which case all bets are off.