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Any one see the Lexicon MC-12HD replacement at CES? - Page 41

post #1201 of 1296
Quote:
Originally Posted by sdurani View Post

As mentioned in my previous post, only PLIIx Music mode has adjustable parameters. Also, are you trying it with 2-channel sources or 5.1 sources? PLIIx can't adjust centre and surround extraction with multi-channel sources.

I was messing around with both, I'll check out the music mode more, but it seems like my intial impressions are going to hold, PLIIX is not as adjustable and does not sound as good as Logic 7.
post #1202 of 1296
Thanks. Does ML offer an AVR or were you using one of its products as some type of baseline? Did the Anthem perform similarly to the other Japanese AVRs?
post #1203 of 1296
Quote:
Originally Posted by Raul GS View Post

Thanks. Does ML offer an AVR or were you using one of its products as some type of baseline? Did the Anthem perform similarly to the other Japanese AVRs?
I am using two Mark Levinson products: one is the No 502 which is a full blown processor and has HDMI. It is a forgotten product but still being built and after this article, folks may want to give it a second look wink.gifsmile.gif. The other ML is just my 10+ year old No 36S DAC which naturally doesn't have HDMI but as you say, it is useful as a reference of what an older but premium product did on that front.

Currently it is my plan to mention the models and brands of the equipment tested but not associate them with the graphs/measurements. I don't want to start world war three with the manufacturers. smile.gif It is my goal to write an educational piece as opposed to a product comparison one. The reason for so much gear is to show that issues persist across products so it is not isolated one bad or good implementation. That said, I may however identify the best performing products so that they get the kudos they deserve and hopefully that will convince the others to strive for better fidelity. Given that, you may be able to narrow the results some. For the same reason I unfortunately can't answer your specific question regarding Anthem here.

Also please note that my data as of this moment is still preliminary. I will be refining and double checking them as the week goes by and then have the final answers when I write the article (this weekend or so).
post #1204 of 1296
Quote:
Originally Posted by swanlee View Post

PLIIX is not as adjustable and does not sound as good as Logic 7.
No argument about L7 having more adjustable parameters, hence the reason I still hold on to my MC-12HD. Well, that and having gotten used to HDMI and room correction over the last 7-9 years, despite being skeptical about both initially.

As for PLIIx not sounding as good, it depends on source material and preference. Hard for me to make a blanket statement since I know people that prefer PLIIx to L7. I tend to use PLIIx with movies/TV but always use L7 with music (multi-channel and 2-channel). But, I don't want to state my subjective preference as an objective fact.
post #1205 of 1296
Quote:
Originally Posted by amirm View Post

I will be refining and double checking them as the week goes by and then have the final answers when I write the article (this weekend or so).
Sounds very interesting. I assume you are probably going to start a thread in at least one forum once the article is printed. If you choose not to start a thread here, maybe you can just give a heads up when the article is published so that we can know when to look for it and where to go wink.gif
post #1206 of 1296
Quote:
Originally Posted by Raul GS View Post

Sounds very interesting. I assume you are probably going to start a thread in at least one forum once the article is printed. If you choose not to start a thread here, maybe you can just give a heads up when the article is published so that we can know when to look for it and where to go wink.gif
Thanks. I submitted it to WSR yesterday. It was a fun project, gaining insight into the performance of these products. It is for the February edition so probably out in 2-3 weeks.

Here is a shot of my workbench as an early teaser smile.gif

i-T8VfGXr-L.jpg

And yes, I will a) put a version of the article online (in http://www.madronadigital.com/Library/Library.html) and b) create a thread on WBF Forum about it (in the "What's Best In Tech Talk" subforum). If I remember, I will post a link to it here also.
post #1207 of 1296
SWEET!!!biggrin.gif
post #1208 of 1296
Quote:
Originally Posted by Peter Nielsen View Post

Right on! JBL Synthesis tech support is a true pleasure to deal with. I'd rather deal with them than with the unknown (Bryston). I have no doubts that Bryston tech support is great too, but I have no experience in this area. All I know is that JBL rocks! smile.gif

Peter - did you get your JBL/Bryston processor yet? I was curious how different the software was vs the Bryston (if they are different at all).
post #1209 of 1296
Quote:
Originally Posted by adidino View Post

Peter - did you get your JBL/Bryston processor yet? I was curious how different the software was vs the Bryston (if they are different at all).

Still waiting. It will be available end of March. I doubt the software will be much different, but we'll see.

My guess is that the only notable software changes are a change of display logo and different default settings adapted for Synthesis setups.
post #1210 of 1296
Quote:
Originally Posted by Peter Nielsen View Post

Still waiting. It will be available end of March. I doubt the software will be much different, but we'll see.

My guess is that the only notable software changes are a change of display logo and different default settings adapted for Synthesis setups.
Your conclusion is right but not the direction you are going smile.gif. Harman has put the product through extensive qualification and getting problems they are finding resolved. So when it is all said and done, it will be the same from both companies but benefiting from another set of eyes/QA on it.
post #1211 of 1296
Quote:
Originally Posted by amirm View Post

Your conclusion is right but not the direction you are going smile.gif. Harman has put the product through extensive qualification and getting problems they are finding resolved. So when it is all said and done, it will be the same from both companies but benefiting from another set of eyes/QA on it.

Amir - do you feel there is any real benefit going with the JBL Synth version over the Bryston or vice versa?
post #1212 of 1296
Quote:
Originally Posted by filecat13 View Post

Hearing something, especially a costly investment like Synthesis®, is always important before purchasing.

I wanted to comment on this, because I never listened to a single Synthesis component before purchase (which probably was a good thing in retrospect). I went about the whole thing in a different, albeit logical manner:

When it comes to the equipment, it's usually the speakers that have the most impact. That said, I started out with a Syntehsis One Array speaker-only setup. The electronics I used was TacT Audio (16 channels of Boz digital amplifiers and a TCS Mk 3). This setup was awesome! Unfortunately the TCS Mk 3 processor had a ton of problems with HDMI and a few other severe functional issues that made the experience sour. When it worked, it was to die for. When it did not, I was fearing a stoke having to deal with the issues and Radomir Bozovic (the guy behind TacT USA). Sometimes I had to wait 3 months (!) for a bug fix or repair.

The TacT problems were unsolved with the demise of TacT audio last summer. This led me to take the leap and finally throw out the processor. A very expensive upgrade, because at the same time the amplifiers (which I loved) had to go because they only accepted digital input and to make things worse, the only way to use them properly was to have a processor that controls the Boz amp setup. I was locked into an amp/prepro combo.

The Boz amps were replaced with JBL S7165 and S820 amplifiers after I read a review by Jiri at HTForums.nl. He raved about the total "blackness" (=quietness) of the S7165. This made me take a leap of faith and purchase the Synthesis amps. What intially held me back was that I feared that the background noise of these analog amplifiers would be an issue, but fortunately I was wrong. The background noise in these amps is very low and is not an issue at all. Another thing that worried me was that the fans in the amps would be noisy. This did prove to be an issue. With the higher room temperatures I and my family prefer here in the south, the fans would come on within 15-30 minutes. The fans are not quiet and to make things worse, they make a non-unform annoying slow grinding noise. This was solved by moving the amp rack into another room. This also took care of stray light from the LEDs, so in the progress I killed two birds with one stone. To be fair I would like to say that you should never consider to use these amps in the same room if silence is important to you. It won't work out, beleive me!

The SDEC-4500 is another story. After setting this up I ran into the problem that the background noise (hiss) of this unit is very high and really is an audible nuisance in a small quiet room like mine. After doing a bit of research, calculations, and checking with Harman tech support, I decided to install attenutors in the XLR connectors of all amps to mute the signal by -12dB (the highest "safe" attenuation according to my calculations when looking at the SDEC-4500 and S7165/S820 specifications). This was a great success! All backgound noise is now gone and the system is perfect! Oh, the fans in the SDEC-4500 are jet engines. Don't even think of putting these units inside the HT if you're sensitive to fan noise like me.

(My local North Carolina displaying dealer has a Syntesis One setup and I listened to the background hiss in his system. It is identical to what I experienced in my system before solving the issue, so the hiss I experienced and found unacceptable is totally normal. The SNR calculations I did also confirm this, so it's no mystery. Fortunately it is solvable by installing attenuators).
post #1213 of 1296
Quote:
Originally Posted by Peter Nielsen View Post


(My local North Carolina displaying dealer has a Syntesis One setup and I listened to the background hiss in his system. It is identical to what I experienced in my system before solving the issue, so the hiss I experienced and found unacceptable is totally normal. The SNR calculations I did also confirm this, so it's no mystery. Fortunately it is solvable by installing attenuators).

Although this seems to be normal for JBL Synth based on your findings, I'm not sure I would find that to be acceptable. Nothing from the JBL Synthesis is cheap. Noisy background corrected by attenuators sounds like a design flaw to me. No?
post #1214 of 1296
Quote:
Originally Posted by Peter Nielsen View Post

Oh, the fans in the SDEC-4500 are jet engines. Don't even think of putting these units inside the HT if you're sensitive to fan noise like me.
Those fans can be disabled. That is what I have done to my machine. You simply open the box and remove the connectors to the fans and you have a dead quiet unit. These units are based on BSS DSP units that are designed to work in rugged/harsh environment and hence the multiple fans. In typical residential setting where they run at room temp (and hopefully not on top of an amp), passive cooling works perfectly. Mine without any fans running just gets a bit warm and that is it. And yes, the mod is blessed by Harman. Your dealer should be able to do it easily.
Quote:
(My local North Carolina displaying dealer has a Syntesis One setup and I listened to the background hiss in his system. It is identical to what I experienced in my system before solving the issue, so the hiss I experienced and found unacceptable is totally normal. The SNR calculations I did also confirm this, so it's no mystery. Fortunately it is solvable by installing attenuators).
That's strange. We have a full synthesis system but don't have any audio hiss even when I stand next to the screen (speakers are behind it). We have the same S820 but the S5165 amps. What speakers are you driving with them? And what is your source/switcher?

At home, I have he SDEC-4500 driving a proceed amp and then to my Revel speakers. Again, no noise at all. This is balanced connection from the processor through the amp.
post #1215 of 1296
Quote:
Originally Posted by adidino View Post

Amir - do you feel there is any real benefit going with the JBL Synth version over the Bryston or vice versa?
There might be in the future. That is all I will say smile.gif.

P.S. Please don't hold me to it. smile.gif
post #1216 of 1296
Quote:
Originally Posted by amirm View Post

Those fans can be disabled. That is what I have done to my machine. You simply open the box and remove the connectors to the fans and you have a dead quiet unit.

Yes, you told me that. However, after trying this and measuring internal temperatures, I was not comfortable with it, fearing it will wear out components prematurely. The stock configuration does have excessive air flow, so I reduced the fan speed by installing a pair of 1N4148 diodes in series with each of the 4 fans in each unit. That way the temperature is kept on leach and the unit is a little bit less noisy.

FWIW, we keep 78F in the theatre in the summertime and never below 72F in the winter. For those that keep 68F or lower around the year, disabling the fans may be more realistic.
Quote:
Originally Posted by amirm View Post

And yes, the mod is blessed by Harman.

Really?! Thanks for that info. I need to check this with them, because it would be nice to have them completely silent.

Does Harman allow this mod while keeping the unit powered on 24/7, or have you installed a trigger to turn off the SDEC along with the amplifiers? (I can imagine that heat is less of an issue if you power off the SDEC after use).
Quote:
Originally Posted by amirm View Post

What speakers are you driving with them?

The speakers that matter (have HF drivers): 3xSAM1HF (active configuration - no SAM12X) and 4xS4Ai in a 16x22' room. Balanced connectors to S7165.

I can hear the hiss at the sweet spot without a processor connected or with the master level of the SDEC turned down all the way. The noise is generated by the SDEC, no doubt! If powering off (or disconnecting) the SDEC, the noise disappears.
Quote:
Originally Posted by amirm View Post

At home, I have he SDEC-4500 driving a proceed amp and then to my Revel speakers. Again, no noise at all.

The most likely explanation is that your Revels are not nearly as sensitive as the SAM1HF (98dB/1W/1m).

The head field technician at Harman was involved, and he admitted that they sometimes install attenuators in situations like mine. It's a real issue, but fortunately it can be solved!
Edited by Peter Nielsen - 1/30/13 at 8:42pm
post #1217 of 1296
Quote:
Originally Posted by adidino View Post

Although this seems to be normal for JBL Synth based on your findings, I'm not sure I would find that to be acceptable. Nothing from the JBL Synthesis is cheap. Noisy background corrected by attenuators sounds like a design flaw to me. No?

Keep in mind that I installed an ACTIVELY triamped One Array into a very small room (16x22'). Such a setup is intended for a much larger space. If it was installed in the intended target space (maybe 30x50'?), then you probably would not hear any hiss. If you don't go with active bi/tri-amping and install the SAM12X passive crossovers for SAM1HF/SAM2LF, speaker sensitivity is reduced to a point where hiss may be a non-issue or at least much less noticable. I just happened to set up a configuration that really brings out the issue.

The EQ (SDEC-4500P/X) combo that harman uses are rebadged BSS BLU-120 and BLU-160 pro-audio units. As such, the specs are set accordingly. The dynamic range of 108dB relate to a maximum output of +19dBu, giving a total SNR of "only" 93dB at +4dBu (which is close to the level where the S7165 has the max output power). In effect, we have 15dB of "unused" headroom to play with when needed - which is nice since this headroom allows us to attenuate by 12dB for the S7165 without bad side effects. Those that have followed the discussions about the Datasat AP20 professional unit may also remember that home users found the unit has high background noise -- it's a completely normal issue with pro gear that need to allow higher output levels than are normally needed by consumer gear/amps. Datasat solved it by providing a unit adapted for home use: the RS20i. JBL has not seen a need to adapt the SDEC-4500 specifially for the Synthesis amplifiers, but the issue can be fixed externally by attenuation if needed so it is a non-issue. Also, optimizing the output level specifically for the Synthesis amplifiers could potentially cause limitations in installations that use SDEC with other amplifiers (Crown Pro Amps, third party subwoofers, etc). It makes perfect sense that Harman has not attenuated the output specifially for the Synthesis amps. However, it would of course be nice if this issue was documented somewhere so those that experience hiss know why it's happening and how to deal with it.

Harman customer support said they have been using the STP-1 attenuators from RDL Labs with good results. While this adjustable attenuator will work, using them would in my opinion give the impression of a lab experiment and not a finished install. I designed my own attenuators: A custom designed 0.43" diameter circular PCB with 0.25% tolerance 0604 SMD resistors in U-pad configuration that fits nicely inside the shells of the XLR connectors. This allows for cleanly soldered wires and no heat shrink mess trying soldering the resistors directly to the contact/wires. The end result is a very clean install - nobody can tell that the attenuators are there unless they dismantle the XLR connectors, and even then what they see will appear store-bought. That's the way it should be! biggrin.gif
Edited by Peter Nielsen - 1/30/13 at 9:21pm
post #1218 of 1296
Quote:
Originally Posted by Peter Nielsen View Post

Keep in mind that I installed an ACTIVELY triamped One Array into a very small room (16x22'). Such a setup is intended for a much larger space. If it was installed in the intended target space (maybe 30x50'?), then you probably would not hear any hiss. If you don't go with active bi/tri-amping and install the SAM12X passive crossovers for SAM1HF/SAM2LF, speaker sensitivity is reduced to a point where hiss may be a non-issue or at least much less noticable. I just happened to set up a configuration that really brings out the issue.

Still not good though and I'm not sure that is the reason. My Triad Platinum LCR's are designed for huge rooms as well. My room is closer to 12x22 and they are dead quiet. The Plats are very sensative speakers as well.

Must be something else going on. Not sure what though.. I just don't think you should need to install attenuators in a high end system like that. Unless you have a grounding issue in the house or their is an issue with the eq since you said it goes away when taken out of the chain.
post #1219 of 1296
Quote:
Originally Posted by adidino View Post

Still not good though and I'm not sure that is the reason. My Triad Platinum LCR's are designed for huge rooms as well. My room is closer to 12x22 and they are dead quiet. The Plats are very sensative speakers as well. Must be something else going on.
Actually it is possible. The same issue can be found with other pro items (e.g. Eqs). With regards to efficiency, you speakers are efficient but they seem to be at least 3dB less efficient than the SAM12X. Are your speakers active as well? I'm not stating that you are wrong, I'm just disagreeing with your quick dismissal of PN's explanation.
post #1220 of 1296
Quote:
Originally Posted by Raul GS View Post

Actually it is possible. The same issue can be found with other pro items (e.g. Eqs). With regards to efficiency, you speakers are efficient but they seem to be at least 3dB less efficient than the SAM12X. Are your speakers active as well? I'm not stating that you are wrong, I'm just disagreeing with your quick dismissal of PN's explanation.

They are not powered. It's just concerning to me that that such a highly regarded home cinema solution is noisy. Just shouldnt be the case. Maybe it is the speakers but that's a serious flaw in my opinion.
post #1221 of 1296
Quote:
Originally Posted by Peter Nielsen View Post

Does Harman allow this mod while keeping the unit powered on 24/7, or have you installed a trigger to turn off the SDEC along with the amplifiers? (I can imagine that heat is less of an issue if you power off the SDEC after use).
This is an informal allowance from Harman. It relies on your dealer taking care with where the device is and keeping it cool. So I can't give you specific answer there. In my case, I have left mine on for days (by accident smile.gif ), with no issues at all. I always check while I am near the unit but it never gets too hot.
Quote:
The speakers that matter (have HF drivers): 3xSAM1HF (active configuration - no SAM12X) and 4xS4Ai in a 16x22' room. Balanced connectors to S7165.
Our fronts are also SAM1HF. So no difference there.
Quote:
I can hear the hiss at the sweet spot without a processor connected or with the master level of the SDEC turned down all the way. The noise is generated by the SDEC, no doubt! If powering off (or disconnecting) the SDEC, the noise disappears.
The most likely explanation is that your Revels are not nearly as sensitive as the SAM1HF (98dB/1W/1m).
I have had noisy electronics emit noise on the Revels. But per above, our other system uses your speakers and with no issues.
Quote:
The head field technician at Harman was involved, and he admitted that they sometimes install attenuators in situations like mine. It's a real issue, but fortunately it can be solved!
I am looking into this. For now, can you say what is upstream of the SDEC and how it is interconnected? I..e what processor do you have for your AV switching/decoding and how it is connected to SDEC (if balanced, whether it is true balanced or the fake variety).
post #1222 of 1296
Quote:
Originally Posted by amirm View Post

I am looking into this. For now, can you say what is upstream of the SDEC and how it is interconnected? I..e what processor do you have for your AV switching/decoding and how it is connected to SDEC (if balanced, whether it is true balanced or the fake variety).

Onkyo PR-SC5509 (same unit as the Integra 80.3). I have a true balanced connection. It did not matter if the Onkyo is on, or off. The hiss was there regardless. Even if I disconnected the 8 Phonenix input connectors from the SDEC, the hiss was there. It is totally obvious that the SDEC is the source of the hiss.

My dealer's system (which in this aspect is identical to mine) emits the same level of hiss, so I don't think I've got a bad SDEC.

Just because you can't hear it, it does not mean that the hiss is not there. Not everybody has the same level of hearing in the HF domain biggrin.gif

Nothing new here. Déjà vu. I'm hearing the same arguments dating back to 27 years ago when I had similar dealer-customer arguments:

The issue with highly efficient/sensitive speakers and amplifier hiss became obvious to me when I got my Technics high-end SB-M1 speakers back in 1986 and powered these with the state-of-the-art Technics SE-A100/SU-A200 combo and experienced hiss. These speakers had a sensitivity similar to the SAM1HF. (The sensitivity of the SB-M1 is 96dB/1M/0.8W - note the odd 0.8W specification which means the dB figure is even higher at 1W)
Edited by Peter Nielsen - 1/31/13 at 4:38pm
post #1223 of 1296
Quote:
Originally Posted by adidino View Post

They are not powered. It's just concerning to me that that such a highly regarded home cinema solution is noisy. Just shouldnt be the case. Maybe it is the speakers but that's a serious flaw in my opinion.

You're trying to make this easier than it is. It's a question of prioritizing. My room is so small that the maximum output of the One Array system will ruin my hearing and probably cause my ears to bleed. I will never use the extreme upper range, so I opt to attenuate in order to get less hiss traded for potentially more distorsion in the extreme upper range. JBL decided to optimize contrary to this and chose to have the best possible sound in the extreme end while accepting a bit off hiss.

In all honesty, during movies the projector background noise drowns the hiss to the point that I really have to listen for it. During movies it is simply not an issue! However, this is not the case when listening to music with the projector off alone in a very quiet room...

Let me give you the exact answer Harman gave me regarding the hiss I experienced:

"This is directly related to the gain structure of the SDEC to the amps (and to some degree the preamp). We do have some noise reduction happening in the SDEC to reduce this when no audio is playing. You can use attenuators on the output of the SDEC, and we have used the STP-1 from RDL Labs for this with good results, but at some point you are giving up internal digital resolution and headroom, and risking overloading the digital filters/DSP during normal listening for an improvement in noise floor when there is no audio or the system is not making sound. Of course the system should always be on and making sound.

In most rooms, the noise of the system is just at the noise floor of the room, and only in the truly exceptional, quiet rooms do you hear a hiss. It should also be clear that once any audio is playing the hiss is completely masked and the benefit is that we can play with much higher headroom and output than any other way possible.

The company suggestion is to play the system at a normal level without adjusting the gain for hiss and see if you can still hear it. You most likely cannot. We also do not suggest sticking your ear in any speaker while a movie is playing as this will cause hearing damage and is an unrealistic test of a noise floor.

In short, in some installations, there can be a very low hiss from the SDEC, but for most rooms you cannot hear it under normal listening conditions, with the benefit being higher output and lower distortion both in the analog and digital sections. We feel the benefits are worth it."

I was happy with this response, except that it would have been nice if they had specified eactly what "at some point" means for the specific Synthesis amps I'm using. My calculations say that 12dB attenuation is OK with the Synthesis amps, but I did not get that confirmed. It is clear that a detailed corrent answer will depend on what amps/subs are used in the setup.

In any case, my system now works PERFECTLY with the attenuation implemented. Why is it so hard to accept that Synthesis may need a bit of tweaking??? I'm a happy customer that spent a lot of cash and despite a few minor issues I got everything set up perfectly. Yet you guys are angry birds with nothing at stake... confused.gif
Edited by Peter Nielsen - 1/31/13 at 5:14pm
post #1224 of 1296
Nothing wrong with tweaking just seems odd to me regarding the noise. Maybe it's less of an issue than I'm imaging. I would just expect dead quiet noise floor from Synthesis. Maybe my expectations are too high... I'm sure the system sounds great regardless.
post #1225 of 1296
Quote:
Originally Posted by Peter Nielsen View Post

Onkyo PR-SC5509 (same unit as the Integra 80.3). I have a true balanced connection. It did not matter if the Onkyo is on, or off. The hiss was there regardless. Even if I disconnected the 8 Phonenix input connectors from the SDEC, the hiss was there. It is totally obvious that the SDEC is the source of the hiss.
Can you run a quick test? Connect one channel using unbalanced (RCA) connector and report back if it still makes a hiss.
Quote:
My dealer's system (which in this aspect is identical to mine) emits the same level of hiss, so I don't think I've got a bad SDEC.
Didn't assume at all that it is a bad SDEC.
Quote:
Just because you can't hear it, it does not mean that the hiss is not there. Not everybody has the same level of hearing in the HF domain biggrin.gif
I have not said once that your hiss is not there. By the same token, let's not presume that you know what my hearing ability is. I have a theory I am pursuing per above to figure out what is going on in your situation that is different than our experience. You should not feel defensive this way. If it is bothersome to discuss it, let me know and we can stop.
Quote:
Nothing new here. Déjà vu. I'm hearing the same arguments dating back to 27 years ago when I had similar dealer-customer arguments:

The issue with highly efficient/sensitive speakers and amplifier hiss became obvious to me when I got my Technics high-end SB-M1 speakers back in 1986 and powered these with the state-of-the-art Technics SE-A100/SU-A200 combo and experienced hiss. These speakers had a sensitivity similar to the SAM1HF. (The sensitivity of the SB-M1 is 96dB/1M/0.8W - note the odd 0.8W specification which means the dB figure is even higher at 1W)
No one is saying that hiss is non-existent in consumer market. It is. When we set up our reference theater, we had two parallel systems as per below picture:

TheaterFrontWall-small.jpg

As soon as the systems we set up, I heard a hiss. It was audible from about 6 feet of the front wall. I immediately assumed what you assumed: that it was the JBL system due to sensitivity of the speakers. Wrong! It was the parallel system with those arrays, planar drivers and their dedicated amplifiers (from the same company). Their amps had better specs than the JBL's as far as SNR so on paper that did not make sense. Yet, they were hissing like there was no tomorrow. We changed out the amps to Mark Levinson and the hiss disappeared. I then connected the hissing amp to Revel Salon2 speakers and the hiss was clearly audible there just the same. So much for your theory of me not hearing hiss and Revel's not being sensitive enough wink.gifsmile.gif.

Please remember that speaker sensitivity is not a standardized parameters, nor at all frequencies so the paper math on what that means in the context of noise, power, etc. can be way off. The hiss spectrum may not at all align with where the speaker is most sensitive.

Anyway, per above, if you are not interested in discussing this issue, that is fine. We can move on.
post #1226 of 1296
Quote:
Originally Posted by amirm View Post

Can you run a quick test? Connect one channel using unbalanced (RCA) connector and report back if it still makes a hiss.

Between SDEC and Amplifier, or SDEC and PrePro? I'm assuming you mean between SDEC and Amplifier, since the latter would make no difference.
Quote:
Originally Posted by amirm View Post

let's not presume that you know what my hearing ability is.

Agreed. FWIW I'm sure you would hear the hiss too. It's obvious after all.
Quote:
Originally Posted by amirm View Post

As soon as the systems we set up, I heard a hiss. It was audible from about 6 feet of the front wall. I immediately assumed what you assumed: that it was the JBL system due to sensitivity of the speakers.
Wrong! It was the parallel system with those arrays, planar drivers and their dedicated amplifiers (from the same company). Their amps had better specs than the JBL's as far as SNR so on paper that did not make sense. Yet, they were hissing like there was no tomorrow. We changed out the amps to Mark Levinson and the hiss disappeared. I then connected the hissing amp to Revel Salon2 speakers and the hiss was clearly audible there just the same. So much for your theory of me not hearing hiss and Revel's not being sensitive enough wink.gifsmile.gif.

Before setting up the system, I tested every amplifier. I ran them in stereo (2 channels at a time for the 7165 multichannel amps). I did this in 2-3 hour sessions with new channels every night. Good thing I did this, because I found one S820 channel that made some odd noises the first minutes of power up. JBL tankfully replaced that amp for me. So I have verifed each channel separately for any oddities.

I also know for sure that the JBL amplifiers are dead quiet. They make no hiss if connected directly to the source or prepro with balanced cables. Also, if the amplifiers were making the hiss, then attenuating the SDEC output signal would not help much.

Amps (and of course speakers) are ruled out, as everything work hiss free if we take the SDEC out of the equation. (Connect prepro directly to amps).

However, your suggestion to try unbalanced brings up an interesting issue. During my initial experiments to combat the SDEC hiss, I created two XLR attenuators for testing. These U-pads with three 1,000 ohm resistors for an attenuation of approximately 9.5dB and another with 2k legs for 14dB. After listening to how much these reduced the hiss in one single speaker, concluded that the 9.5dB attenuation possibly would be sufficient, but it was still far from perfect. The 14dB pad was pretty good, but being that I did this test for only one channel, I still was not sure if that would be enough.

I then took a leap of faith and created 12dB U-pads for all channels, but now I chose an input impedance of 500 ohm instead of 1kOhm. To my surprise the result was much better than I expected with all hiss now gone. I still find this a bit surprising, so I wonder if it's possibly the lower resistance load on the SDEC balanced outputs that reduces the hiss more than the added attenuation does. Since I got everything working to my satisfaction I did not look futher into this. I probably should try to make a 0dB pad with 500 ohm and see how that works out - at least this would give the answer to whether it's the attenuation or lower impedance (resistance) load that has the most impact on the hiss.

When thinking more about this, I realize I need to do what you suggest and try running one channel unattenuated and unbalanced to see if that makes a difference. It actually might!
Edited by Peter Nielsen - 2/1/13 at 7:20am
post #1227 of 1296
Not that the JBL Synthesis troubleshooting discussion isn't interesting, but wouldn't it be more appropriate to move it to a new thread (so we can get back to bashing Lexicon for not releasing anything new in this thread biggrin.gif)?
post #1228 of 1296
Quote:
Originally Posted by Peter Nielsen View Post

Between SDEC and Amplifier, or SDEC and PrePro? I'm assuming you mean between SDEC and Amplifier, since the latter would make no difference.
No, I did mean between the PrePro and SDEC. We have run into instances where if the source is not truly balanced (i.e. electrically differential or transformer based), then it will cause the SDEC to generate hiss. The solution in that case is to use unbalanced and hence my suggestion to try that. We have seen this with Marantz "balanced" outputs for example. I am not sure if the Onkyo is the same but thought it is faster to try it than to dig into the design smile.gif.
post #1229 of 1296
Quote:
Originally Posted by gsr View Post

Not that the JBL Synthesis troubleshooting discussion isn't interesting, but wouldn't it be more appropriate to move it to a new thread (so we can get back to bashing Lexicon for not releasing anything new in this thread biggrin.gif)?

True, but then this thread might die.

For the record:

SAM1HF/SAM2LF across the front
S4Ai sides and rears
S1S-EX (2) and 4645C (2) subs
S800 amps (4)
S5160 amps (2)
AV-2
SDEC4000
unbalanced StraightWire Synthesis® connectors

No hiss.
No hum.

Relative to the topic, it might be the different SDEC or the unbalanced connectors. My (older) Synthesis® One Array has no other option than unbalanced connectors from AV-2 to SDEC4000 and from SDEC4000 to the amps. It originally came with an SDP-5, which I replaced with the AV-2 to get HDMI and 7.1 analog inputs.

The system has two dedicated 20A circuits. The amps are plugged direct into one and the rest of the electronics go through a Furman PM-Pro unit plugged into the other, but I doubt the relevance of any of that.

Personally, I'm very happy that there either is no hiss or it's so slight that I can't hear it. Either way, I'm a happy camper. I would not want Peter's curse. redface.gif
Edited by filecat13 - 2/1/13 at 1:07pm
post #1230 of 1296
Quote:
Originally Posted by filecat13 View Post

Personally, I'm very happy that there either is no hiss or it's so slight that I can't hear it. Either way, I'm a happy camper. I would not want Peter's curse. redface.gif

Let me just clarify so that there are no mistakes: With attenuation in place I am a happy camper too! However, I completely agree with Amir that it would be nice to get to the root of the cause and find out why I had to apply attenuation, especially considering that you guys obviously do fine without it.

FileCat, thanks for letting me know that you're running unbalanced. It sure is starting to sound like the issue possibly could be related to the use of balanced connections. Clearly the next thing I need to try is an unbalanced connection. In fact, I should probably have tried that before trying to solve it with attenuation rolleyes.gif

Amir, are you using balanced or unbalanced in your S5165 setup ?
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