Stereo = Front Mains?

**Chrisbee** · **08-29-06, 11:31 AM**

Is there any difference between an analogue signal from the RCA/phono Stereo sockets and that from the Front Mains signals from their respective 6-channel analogue RCA/phono sockets on the same DVDP?

Are they interchangeable?

**JCD** · **08-29-06, 02:40 PM**

I'm not sure I follow.. are you saying that there is a 5 channel out (for DD) AND a separate 2 channel out (for stereo music) from your DVD player?

If so, my GUESS would be that the signals are different -- full two channel on one and the discrete l/r channels in DD on the other. If it were stereo only, then maybe they would be the same.

I'm sure someone smarter will confirm or deny my answer..

JCD

**Chrisbee** · **08-29-06, 04:00 PM**

From here on it gets horribly complicated:

On my NAD T533 DVDP I have 5.1 analogue out and stereo L&R out sockets as well as various digital connection options.

I'm curious to know what the difference is between the discrete L&R mains and the stereo L&R when watching DVDs.

At the moment I use the analogue stereo sockets on the DVDP for films because of the natural sound quality from my Naim pre-power. I could put the L&R analogue Mains signals though my Naim pre-power but the SQ doesn't seem as good as the stereo option. Presumably the processing is taking its toll and the Naim gear is ruthlessly exposing it.

I'm trying to avoid pushing the Front Mains signal through my old Yamaha 3.1 DSP E800 Processor. When I put the whole 5.1 from the DVDP through the Yamaha DSP the sound quality is very disappointing from the mains. The same problem using the digital connections. So I connect only the analogue Rears to the DSP from the DVDP and and enjoy rather basic 4.0 Dolby surround but with sub-10Hz extension from the IB.

I am really not sure redirecting bass from setting Rears to small (and Centre=No) works with the stereo sockets. Logically it shouldn't. The problem is I need the all redirected bass I can get for my biamped IB. Which is running in parallel (via active CX) with my stereo/Mains.

NAD has told me not to try and use the DVDP as a processor like this and I should just buy an AV receiver (preferably one of theirs of course). I haven't heard an AV 5.1 receiver I really like yet at a price I am willing to accept to try and compete against the superb Naim stereo SQ on DVDs.

The top-end NAD kit is indeed rather nice but just too expensive for my (wife's) tastes. I haven't heard the mid-priced models but assume they will offer typical mid-price SQ however affordable they may seem.

Which brings me right back to square one. I am unwilling to give up my Naim SQ on films. So I must try and achieve a better surround compromise that works without expending a fortune on new kit. Are there any other possible options open to me?

All suggestions warmly welcomed.

**eddthompson** · **08-29-06, 06:42 PM**

id imagine, if you dvdp is like mine, the stereo outs are the stereo down mix from the DD 5.1, NOT the L and R channels.

The way your doing it, id guess the sound effects destined for the rear are being sent to the fronts as well.

On my denon, the is an option called "source direct", this kills all processing other than the decoding, and the 5.1 sockets sound pretty decent using this.

My problem is i need the sound crossed over at 80hz (thx speakers) so i run the dvd player with its processing, the delay and bass management is pretty good for sacds, and even cds, makes the imaging much better.

For DD/DTS though, i use coax to my reciver and let it decode it all.

ps, if you like the naim "sound" i doubt any av gear will appease you :P

edd

**Chrisbee** · **08-30-06, 01:44 AM**

Hi Edd.

I think I shall just have to try the Front Mains analogue outs again to feed the Naim pre for films. That should ensure bass redirection from Rears and Centre finds it way home to the Mains.

I liked the CD analogue stereo perfomance on the NAD DVDP so much I stopped using my CD player for quite some time. It has a silky smooth quality but perhaps lacks a little "excitement". My wife calls it; "easy listening" on a good day.

The only reason I'm getting "hot and bothered" about all of this is worrying about my missing redirected bass. I'd like even greater dynamics from my IB but can't seem to get the missing LFE because of my CX-split, front mains/IB setup.

**Chrisbee** · **08-30-06, 06:58 AM**

I can finally report success!

Using the Front Mains sockets off the DVDP to feed the Naim preamp produced the most brutal AV experience I have ever suffered by a very large margin.

I watched the whole of The Twin Towers with the dialogue averaging 80dB and have just struggled from my chair completely exhausted. I was totally wasted by vicious 110dB (C-uncorrected) effects that had to be heard to be believed. Not just your usual AV booms and yet more booms. But solid reality writ very large. There was no warmth at all. Just incredibly realistic destruction. Exactly as depicted on the screen.

There was an increase in brightness over the stereo sockets but it was well worth it. After months of trying I finally have the IB perfoming just as it should. It went very loud before and I really believed that was as much as it could manage. It just wasn't getting all the bass redirected from the missing channels. Now it is!

Nothing even comes close to what I've just been through.

**eddthompson** · **08-30-06, 07:44 AM**

im pretty sure the .1 channel would have been down mixed to the stereo outs as well, but along with the rear channels at the same time, which could have muddied things.

Another idea to try for 5.1 is perhaps drive your IB with the .1 sub out from you dvd player, the problem you could have here is whether it provides enough drive for the ep2500, and if you can controll the crossover point in your player (i can in mine), although, you would have to set the voulme with the ep2500 everytime you changed volume on the pre.

just get another 2 naim pres

that will give you 6 channels of naimness and great controll over individual levels, and since hd-dvd is going the way of the decoder in the player, your sorted

edd

**Chrisbee** · **08-30-06, 08:41 AM**

edd

The .1 option won't fly without a major rethink and I'm a happy bunny already as far as sub perfomance is concerned.

The stereo option definitely lacked the brutal dynamics I'm suddenly getting now.

The stereo option was actually louder in output so I didn't need as much volume on the preamp. Now I'm at 9 o'clock instead of 8.

I also had exactly the same settings in the DVDP so can only assume that stereo wasn't getting the redirected bass. I'm talking chalk and cheese here on dynamics and bass SQ.

I've had months trying get the IB right on stereo on dozens of films without the result I have achieved only today. It was often very loud before (regularly checked on the meter) but it wasn't brutal like it is now. I also wasn't getting much cone movement or floor effects. Now the baffle wall wants to join the party! I might try sand loading or concrete blocks in the wall to increase inertia. Otherwise its got to be an opposed driver manifold.

Can I live with the slightly increased brightness? I'll just have to learn to. It's just what I've been hearing on every surround system I've ever heard. A slight scratchiness and sibilance is how I would characterise it compared with my usual liquid silk SQ.

**eddthompson** · **08-30-06, 09:26 AM**

Id guess the crushing of dynamics was due to the downmixing, its usualy bad.

With the 5.1 its not downmixed, even when you only use 4.0, it just moves the .1 bass to the fronts, and moves the centre there as well, nothing to complicated.

the shrill brightness etc, well, ive never been a fan of DD or dts, even cd sounds better, another issue of course is at high volumes treble can get out of hand, one of the main reasons apperntly THX rolls it off a little, (according to home theatre secrets anyway)

As i thought about the .1 output i realised it was a no go, but id typed so much i couldnt be bothered to delete it, i like to ramble.

i dont suppose your naim gear has a treble control

i may come across as slightly scathing to naim gear, actualy, i love the stuff, im a real flat earther at heart with reagrds to hifi, but you wouldnt catch me feeding icky digital stuff into salesburys finest, would have to be an lp12, with maybe an aro

i dont have room for a stereo hifi at the moment, so unfortunatly its shoved through the av system, which is purely av in concept, other than the record deck

but i cant be without my vinyl.

edd

**Chrisbee** · **08-30-06, 12:50 PM**

I wouldn't call it shrill by any means.

It's just a slight overemphasis of the high end which exaggerates certain common sounds.

Turning the bass up even higher is a pretty good antidote!

**F1 fan** · **08-30-06, 08:42 PM**

The 2CH and 5.1 front LR outputs on my Pioneer DV563 dvd player are exactly the same.They are parrallel outputs from the same opamp.

**Chrisbee** · **08-31-06, 03:06 AM**

Quote:

F1 fan wrote:

The 2CH and 5.1 front LR outputs on my Pioneer DV563 dvd player are exactly the same.They are parrallel outputs from the same opamp.

Interesting, but how did you discover this?

By lifting the lid?

**eddthompson** · **08-31-06, 04:34 AM**

pretty easy to find out realy, just try both sockets with a test tone like on the avia disc or the thx optimiser, you will soon find out where the rear/centre/sub signals are being routed.

edd

**Chrisbee** · **08-31-06, 12:40 PM**

How does playing a test disk with my DVDP differentiate between stereo L&R and 5.1 Mains L&R?

The DVDP will still play L&R whichever sockets I use. Will it not?

**eddthompson** · **08-31-06, 02:56 PM**

to find out where the rears get routed, also the bass. As a test disc does lesft, centre, right, rear right, rear left, sub you should be able to figure out where they are being routed.

If on the stereo outs the rear effects occur from the fronts as well as the rears, you know its a down mix, rather then just l&r

edd

**brucek** · **08-31-06, 03:01 PM**

Quote:

If on the stereo outs the rear effects occur from the fronts as well as the rears, you know its a down mix, rather then just l&r

Yep...........................

**Chrisbee** · **08-31-06, 03:09 PM**

Quote:

eddthompson wrote:

If on the stereo outs the rear effects occur from the fronts as well as the rears, you know its a down mix, rather then just l&r

edd

How will stereo output to the rears if it's 2.0?

**eddthompson** · **08-31-06, 04:00 PM**

if its down mixed, the stero output will combine the 5.1 sound track into 2 channels.
Including the rear sound effect, much like the L and R would output the rears if you switched off the rears in the speaker size menu.

edd

**F1 fan** · **08-31-06, 06:05 PM**

Quote:

Chrisbee wrote:

Interesting, but how did you discover this?

By lifting the lid?

Yes I lifted the lid to do some mods and I also have the schematic.

**Chrisbee** · **09-01-06, 03:59 AM**

Well, I ran The Calibrator DVD test disk on DD 5.1 ID voice recordings using the analogue Stereo sockets.

L&R ID were normal with total silence from the other (L or R) channel not being tested.

Centre channel clearly came from dead centre between both stereo speakers.

The rear ID signal sounded out of phase (and slightly bassier) but still came from the front speakers.

Sub is set to None in the DVDP menu and produced no signal from the speakers in this test.

Then I switched on my Yamaha rear channel processor/amp.

The rears play normally provided they are connected to the 5.1 rear sockets. Which is to be expected since I was using a 5.1 test. But I was getting a double dose from front and rear by using the Stereo socket connections.

When I move the DVDP output cables over to 5.1 analogue Main L&R sockets the rear signal can no longer be heard from the front speakers.

Interestingly(?) there is no output from any speakers whether sub is set to none or large in the DVDP. There is no difference here wether the DVDP is connected to the stereo or the 5.1 sockets.

My fuzzy logic suggests that the sub channel signal should be sent to the front mains. Obviously it's not! My conclusion is that any bass redirection would have to take place in an AV receiver provided the sub socket on the DVDP was connected. Perhaps bass redirection is only possible in the digital domain with digital cabling?

Conclusions? The Stereo sockets produce a double dose of rears when the rear processor/amp is switched on. So best surround sound should come from the 5.1 discrete sockets. The stereo socket option merely provides a slight "surround effect" to liven up DVD watching.

**eddthompson** · **09-01-06, 05:09 AM**

as i suspected.

on my dvd player, the sub level is very low on these calibration things, ive not tested it with the sub set to off as my speakers roll off at 80hz (stupid thx again).

To get the bass up to a decent level on the analogue cables, i need to run the sub at +10db in the dvdp menus, on the reciver, the mains are at -4 and -1, and the sub i set anywhere between +5 and +12 so using the 5.1 analogue cables the sub is getting between a 15 and 22db boost.

If your running your mains as large, you still will get bass, as the front channels are full range in 5.1, im not to sure where the ,1 track is going at the moment.

There is a 20-20000hz sweep on the thx optimiser, but i dont know if this uses the .1 channel, this could be tricky to sus where you bass is going.

I cant see why the speaker setting would affect the digital, as this would be handled in the reciver, on my system for the coaxial DD link i set all the speakers sizes and distances in the reciver, then have to the same thing in the dvdp for sacd/dvd-audio so i have the correct bass management, and in 5.1 analogue mode, my amp does nothing but change the level.

ramble ramble.

edd

**Chrisbee** · **09-01-06, 05:30 AM**

Not boring at all edd. I'm learning from your experience and that's what is important.

Remember that I don't have a "proper" 5.1 AV receiver. Just the old Yamaha DSP E800. Which may be 5.1 in the processing but is only 3.0 (rears + centre in the amp compartment.

This is why it is important to me to sort out what is happening to the .1 bass.

For DVD films my system is basically a triamped 4.0 DVDP.

I don't like the sound of the Yamaha when it gets its grubby hands on my main speaker signal.

So I'm not giving it that chance just to get the .1 redirected to the mains.

I don't like the Yamaha's SQ on coax digital connections either so that's out.

Until now I've had hardly any interest in the compexities of surround sound. So I really haven't done much reasearch around the subject of LFE redirection.

I cannot imagine many others are using their DVDPs quite like this.

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