Frustration with SurroundBar and DPR-2005

[tiredofspam]

Hello all...sorry for the length of this post, but I'm really aggravated and I wanted to show that I've covered all the bases (anyway, I THINK I have).

This is my first new setup in about ten years so I might be behind the times a bit so I appreciate any suggestions anyone may have.

I've searched the forum and the web and can't find an answer to this problem and I'm about ready to get rid of everything.

Purchased an H/K DPR-1005 back in November and had only front and center speakers (JBL) hooked up while I searched for a full 5.1 (maybe 7.1) setup.

Purchased the Surroundbar (and PSW10 subwoofer) last month - got it home and quickly found a problem. Hooked it up and configured it per the instructions...sounded FANTASTIC...until I selected a mode (any mode) that used the surround speakers.

Terrible hiss...like white noise...even with the volume turned almost all the way down. Sounds like rain...didn't get louder when the volume was turned up but was already pretty loud. Really noticeable in DTS mode (Saving Private Ryan, Apollo 13, etc.) during some quiet scenes but was still loud in any mode that utilized the surround speakers. (Note that when testing DTS mode, I used a DTS DVD player, optical cable, set to DTS/bitstream mode with DTS turned on and a DTS version of the DVD. Just making sure that everyone understands that this isn't due to having anything mismatched though I did try out every possible combination.)

Called Polk Tech Support to verify that it couldn't possibly be the speakers...they said "no", nothing in the SurroundBar could be causing the hiss.

Okay...RMA'd the receiver to HK (cost $32 to ship it)...got a replacement DPR-2005 a few days ago. Hooked it up...same thing. Exactly the same thing.

Checked all the wires - using good quality 12ga stranded O2-free copper for the speakers, very short (less than 18" since the receiver is on a shelf below the SurroundBar)...optical from the Comcast DVR and DVD recorder. Everything is cleanly connected - no shorts. Tried another DVD player connected with optical - same results.

Went to test tone (DTS mode) on the DPR-2005 - cycled through L, R, C, RS...as soon as the LS kicked in, the hiss started and stayed on through subsequent cycles until I exited and started it again. (Same thing happened with the DPR-1005 that I RMA'd.) This eliminated the other boxes - now, the problem is isolated to the receiver and the SurroundBar.

Disconnected the LS and RS wires from the SurroundBar and connected them to my old JBL's...total silence...cranked up SPR and lotsa stuff blowing up on screen (and through all speakers)...but no hiss. Reconnected the RS and still no hiss...reconnected the LS and HISSSSSSSSSSSSS. Tried the opposite - same result: As long as only ONE of the SurroundBar surround channels is hooked up (either one, doesn't matter) and the other connection is hooked up to an external speaker, no hiss. Both hooked up: HISSSSSSSSSSS.

Packed the SurroundBar up (figured there had to be a short in it somewhere) and exchanged it - hooked up the new one and SAME RESULT: HISSSSSSS.

So...now I've switched out an $800 receiver with a $900 receiver and swapped out the SurroundBar with another one...almost $2k for just these components and I've got frigging HISSSSSSSSSSSSSSS.

Anybody got ANY idea WTF the problem is?

Remember...two DIFFERENT model receivers (both HK), two SurroundBars, no shorted connections to the speakers or receiver (high quality copper), optical to the external components (though I can reproduce the hiss in test mode on the receiver when it isn't connected to anything). Only happens in a surround mode - DTS, anything 5.1.

I'm going to call Polk and HK in the morning to see if there is some incompatibility between the SurroundBar and HK digital path receivers.

I'm really po'd by this entire problem - I could have bought a cheap Theater-in-a-box for a fraction of the cost of this setup and not have had any problems. I don't WANT a crappy T-i-a-b...I want THIS to work.

Sorry for venting but has become a very expensive problem.

Thanks for your help.

Dave

[Dennis Gardner]

2 receivers, 2 surround bars, same noise indicates its the DVD Player.

Edit: I reread your post and do think it is a receiver setup issue. I don't have experience with the surround bar but can't imagine it being the problem.

[tiredofspam]

Nope...two different DVD players (both optically connected) and a Media Center PC (coax connected) - same results on all.

(Plus, the test mode on both receivers caused the same hiss without any other components (DVD or PC) connected.)

Thanks for the reply.

Dave

[tiredofspam]

Dennis,

You would think so...the SurroundBar is supposed to be passive and shouldn't cause (or induce) any noise. But, disconnecting one of the surround cables from the SurroundBar (either L or R) and connecting it to another speaker stops the hiss. It only happens in DTS (or any 5.1 mode) with BOTH SurroundBar surround speakers connected.

Very weird.

[Dennis Gardner]

It still sounds like a PCM bitstream issue in the surround channels.

You might check for proper polarity on the surrounds. It sounds like maybe the LS is out of whack and causes some type of oscillating to start. I would also make sure that the receiver is set for 5.1. My HK senses when no speaker exists, but with a surround bar, you should be using sides and not rears.

Other than those ideas, I'm stumped.

[dorokusai]

I just installed a HT for a friend, including a SB and HK AVR, no issues.

Are you using the stock wiring harness for the SB?

Have you tried using a coaxial connection as opposed to optical?

This ONLY happens on DTS?

[tiredofspam]

Dorokusai:

I didn't use the stock harness since it is 25' long and I didn't want (or need) to cut it up in the event that I have to return (as opposed to "exchange") it again.

I used high quality copper for the connections between the receiver and speakers and checked for shorts.

The noise occurs in DTS 5.1 (and any other surround mode that uses the surround channels - the noise stops if I turn off the surrounds (via receiver setup), essentially giving me DTS 3.1).

Which model HK did you set up for your friend? The DPR series are straight digital end-to-end as opposed to the AV series which are analog converted to digital (I think!).

I did speak to Polk tech support and he reiterated that the SurroundBar is passive (which still makes perfect sense since it isn't externally powered).

He DID say something, however, that may shed some light on the problem, at least as far as the DPR-series is concerned (can't speak to the AV-series since I don't have one): The SurroundBar uses a common-ground setup for the connections to the receiver - I haven't been able to find ANY information concerning the connections ON the receiver (i.e. whether it uses a common-ground or floating-ground system). The manual doesn't say anything about the speaker connections other than basic hookup. And one NORMALLY wouldn't hook up a single ground loop (like the SurroundBar uses) for discrete speakers so they may have neglected to mention this in the manual.

Calls to HK have gone unanswered at this point (I've got other issues with my "new" receiver that have to be dealt with (they shipped a refurb unit with no remote instead of a brand new unit that I was promised)). I'll see if I can get an answer from them concerning the internal connections.

Funny thing is: If the SurroundBar uses a common ground system, why is the HK totally silent (as far as the hiss is concerned) when the L, R, C and ONE surround channel is connected? You would think that hooking up ANY TWO of the five would cause a problem since you are essentially shorting out the floating ground at that point.

(Also, I DID try both optical and coaxial...)

Dennis and Dorokusai: I cut all external devices and was able to reproduce the problem in the receiver while performing the test tone setup (see earlier post). It apparently is NOT dependent on the signal coming into the receiver as the test tones trigger the hiss as soon as the last surround channel is activated. (Happened in both the DPR-1005 and DPR-2005. Still happened in the DPR-2005 after I swapped out the SurroundBar.)

Again, thanks for your insight...

[heiney9]

Have you got another AV unit besides the HK? Maybe a buddy or a neighbor could bring a different Receiver over and see what results you get then. I know it's a PITA, but you've already got a lot of time and effort invested. Sorry to hear HK hasn't responded to your inquiries, I've heard they have a great CS department. Your situation maybe the 1 in a million combo that just doesn't work, for whatever reason.

H9

[tiredofspam]

That's my next try...I'll have to tear everything down to do it but I can hook up my old Onkyo. It has Prologic 5.1 but no optical inputs (the main reason I upgraded to the HK).

Didn't get through to HK today so I'll have to try again tomorrow.


Thanks.

[Dennis Gardner]

Try swapping polarity on one of your surrounds. Having them out of phase would look like a short to your receiver since the surrrounds have grounds in common.

[tiredofspam]

I'll give the polarity swap a try tomorrow (after I talk to HK).

Found this: http://forums.audioholics.com/forums...ad.php?t=11546

so I'm not the only one with this type of problem, apparently. (Not SurroundBar but same type of noise.)

[SuperDave]

It does sound like a grounding issue. Make double sure polarities are correct.
Good luck bro
I would not reverse polarity but I would make sure they are all correct.

[tiredofspam]

Thanks.

I just found another enthusiast forum/website where one of the members posted links to service manuals for a boatload of HK receivers (including the DPR 1005/2005).

I checked the schematic and it shows a common ground for all of the speaker connections so it is definitely NOT a floating ground vs. common ground problem.

Here's the link if anyone has an HK receiver (AVR and DPR series):

http://forums.audioholics.com/forums...light=dpr+2005

Back to the drawing board...

(Also, I'll heed SuperDave's advice about NOT changing the polarity of one of the surrounds in light of the common ground confirmation - no sense in purposely dead-shorting the thing.)

Again, I appreciate all of your help.

[Dennis Gardner]

It does sound like a grounding issue. Make double sure polarities are correct.
Good luck bro
I would not reverse polarity but I would make sure they are all correct.

Checking polarity is what I meant to convey. Since you didn't use the harness, something might be switched.

[tiredofspam]

Thanks Dennis,

I figured as much...I did double- and triple-check the polarity.

I think, just for laughs, that I'll use the Polk (25') harness...just to see if it makes a difference. (I'm sure that it won't but, at this point, what the hell?)

[Dennis Gardner]

Are you using side surround or rear surround posts on the AVR?

[tiredofspam]

Side surrounds - manual (and Polk tech guy I talked to today) both say SurrR and SurrL for 5.1.

SBR and SBL are only used for 6.1/7.1 (eventually I want to hook up a pair of rear speaker in addition to the SurroundBar but ain't happenin' until I can get rid of the noise).

So, the configuration (receiver => SurroundBar) is:

Front R => Front Right (and PSW10 subwoofer input Right)
Front L => Front Left (and PSW10 subwoofer input Left)
Center => Center
Surr R => Surround Right
Surr L => Surround Left

[tiredofspam]

Okay....some other weirdness.

The schematic for the DPR-2005 confirms that the receiver uses a common-ground at the binding posts.

The Polk tech guy says that the SurroundBar also uses a common-ground setup.

Ergo...

Since in a common-ground scenario, all of the black terminals on the receiver are hooked up together and all of the black terminals on the SurroundBar are hooked up together, you SHOULDN'T need more than one wire to connect the negs on the receiver to the negs on the SurroundBar.

So I did some experimentin'...

Disconnected the black RS lead at the SurroundBar and ran the test tones in sequence...as soon as the sequence hit the RS, the tone was MUCH louder than when the neg was connected. And, as soon as the sequence hit LS....HISSSSSS (plus the tone) which didn't go away through subsequent cycles until I turned the tone off and started it over.

Disconnected the black LS lead (in addition to the black RS lead) and cycled the tones - louder and hiss.

Remember, there are still three blacks on the receiver hooked up to three blacks (RF, LF, and C) on the SurroundBar - shouldn't have had ANY effect if both the receiver and SurroundBar are common-ground...correct?

(Also disconnected the subwoofer for this test - had no effect.)

Disconnected the RS completely and tried the test - no sound out of the LS at all. Hooked the LS back up (+ and -), no RS and the tones cycled through perfectly with no hiss. (Except for the RS tone which was silent since no RS was hooked up.)

This tells me that more is going on inside the SurroundBar than meets the eye...correct me if I'm wrong but the SurroundBar cannot be common-ground if there isn't a tone in the LS with the LS positive-only and three other negs connected.

I understand the need for grounding the receiver and speakers but common is common - one heavy wire, any neg post on the receiver to any neg post on the SurroundBar should work.

[Dennis Gardner]

SDA effect is done with phase shifting in their older models. A right channel signal is run 180 degrees out of phase at a lower output level into the left SDA speaker. This cancels the inter-aural crosstalk of stereo sources. I don't know how the technology is done in the surround bar, but I assume it is similar. Sound comes from the SDA speaker even without any posts hooked to the corresponding (same side) stereo channel. This is normal.

It does sound like your receiver doesn't like the load being presented by the SDA channels and may thus cause your noise. The SDAs present no problem for my HK AVR7200, but they are an entirely different topology than your DPR.

I have one more hookup suggestion. Hook the main output channels L&R(which you know to work fine) into the surround speakers. If the SDA crossover causes the noise with these good channels, then it is your receiver not being compatible with the SDA wiring scheme.

Good Luck, and sorry for your experience so far,

DG

[tiredofspam]

Since I haven't had any previous experience with SDA-type speakers, I was kind of wondering if this might be "normal". I can almost understand "some" hiss but this is way too annoying to enjoy listening to any 5.1 stuff.

When I listened to the setup at the store, they MAY not have been using a full 5.1 - I certainly know a lot more about this now than I did three weeks ago.

I'll give it a shot and let you know what happens.

Thanks,

Dave

[Dennis Gardner]

Let me assure you that "noise" isn't a normal description for the SDA effect only a wider soundstage of what you are currently getting out of your speakers before connecting the SDA cable. The effect has more to do with cancelling out unwanted crosstalk instead of adding anything.

[shack]

Dorokusai:

I didn't use the stock harness since it is 25' long and I didn't want (or need) to cut it up in the event that I have to return (as opposed to "exchange") it again.

I think I would use the stock harness and see it the issue still persists. Don't cut it...just coil it up. The SDA cable is a key component in the original SDAs. I don't know about the soundbar...but there may be something missing by not using the harness...and causing the hiss.

I think, just for laughs, that I'll use the Polk (25') harness...just to see if it makes a difference. (I'm sure that it won't but, at this point, what the hell?)

Did you?

[tiredofspam]

Just pulled the Polk harness out of the package...to be honest, it is (or looks like) five pair of stranded, unshielded (18ga?) wire with tinned ends.

Doesn't look like anything "special" except for the fact that it is 25' long and wrapped in plastic.

But...what the hell...I'll give it a shot.

[tiredofspam]

Dennis,

Thanks again for your reply. I read the white paper on the technology behind SDA (and SurroundBar). I figured that the cancelling effect was similar to noise cancelling headphones and would reduce rather than create noise.

Sorry to keep beating on this subject but there's a lot of money invested in this HT (including the 42" plasma set and Media Center PC). The wife is about to hang me!

[Dennis Gardner]

Try just the L/R mains hooked into the surrounds. This will isolate if it is a surround decoding error or the surround crossover causing it.

[tiredofspam]

Okay...connected the Polk harness - still have hiss.

So...following Dennis' advice: disconnected everything from the SurroundBar and hooked up the receiver LF to the SurroundBar LSurr and receiver RF to the SurroundBar RSurr.

As soon as the test tones cycle to the LF (LSurr) - the hiss starts.

So, it appears that ANY signal to the SurroundBar surround connections causes the hiss but, again, ONLY when both surround channels are connected. Either one, singly, and I have complete silence except for the test tone.

I pulled out my old (analog) Onkyo TX SV727 (Dolby ProLogic but no DTS) and I'll try it out tomorrow...too late to screw around with it anymore tonight....

Also, since I was holding the SurroundBar in my lap during the testing, I noticed another noise emanating from it (besides the hiss)...hard to describe but it almost sounded like a machine shop banging away through a brick wall. Very rhythmic and cyclic...low frequency but not bassy...I may try to record the noise and save it as a wave file (and post a link) tomorrow to see if anyone can identify it. I'm pretty certain that it ISN'T 60Hz hum (like from a fluorescent bulb or a motor since there isn't anything that could generate this kind of noise within 30 feet of the receiver. I really can't "ground" the receiver to the electrical outlet without physically attaching a wire to it - the power cord, for some reason, is only two conductor (there is NO ground pin on the receiver so I assume it DOESN'T require any external grounding).

I would bet that it is some kind of digital noise but it only occurs in the surround speakers and only when BOTH surrounds are connected. Also, it occurs while using the test tones so it isn't coming from an external source (like the DVD player or PC which are connected optically but turned off).

Ain't nothin' there to generate all that racket!

[shack]

That settles it....gremlins...you have gremlins and you are SOL.

[tiredofspam]

Perhaps a swig of some fine Tennesse Jack would settle the little *&#*@#'s down...

[Dennis Gardner]

Sounds like you've found the first HK/Polk compatibility problem that I've heard of. It has to be in the crossover common grounding of the SDA signal and the receiver reacting to the load it "sees". As has been stated in many threads around these parts, HK and SDA have always been good partners together.

Sorry that you have run into this, as both pieces are nice performers, just not together.

DG

For future search reference: HK/Harman Kardon/DPR/Digital Path Receiver/SDA/Stereo Dimensional Array

[shack]

Nah..you're screwed. They never settle down and they never go away. Just gotta live with them.