950 2 channel bypass vs 6 channel bypass redux

Posted by: HTLearner

950 2 channel bypass vs 6 channel bypass redux - 01/27/03 07:52 PM

Hello fellow Outlaws. I posted this under the "950 2 channel bypass vs 6 channel bypass" thread, but didn't get many responses. I am re-posting here with hopes that you all will help me out.

I still don't think I understand all the differences between 2-channel stereo analog bypass and 6-channel analog direct mode, for stereo sources. I hope you all can set me straight.

My DVD/CD player is a Sony ES9000. It has only stereo 2-channel outputs for analog, no 5.1 analog outputs. Can I plug these into 2 of the 6-channel analog direct inputs on the 950 and get better sound? The ES9000 probably has better DACs than on the 950. Right now I have the ES9000 stereo analog outputs plugged into the 950's stereo analog CD inputs.

I guess I thought I was already using only the ES9000 DACs by choosing analog stereo bypass mode on the 950. How is this different than using 6-channel direct with just the left and right cables plugged in?

My goal is to use the ES9000 DACs and get pure analog sound to the mains and the subwoofer to see how that sounds-- and to still have the other modes (digital) sound good and have bass set up correctly for movies or 5 channel stereo.

So, to do this I should plug the ES9000 into 2 of the 6-channel direct inputs on the 950, turn on the 80 hz crossover switch, and select 6-channel direct mode, correct?

Does anyone have a similar setup and noticed better sound this way? Maybe this is what SDWinder is describing, but I'm not entirely sure.

Two issues I with this approach: I set up the bass to use Small speakers and have a smooth crossover point in digital modes. So it seems like the bass transition may or may not be as smooth using the 80 hz crossover switch in analog direct mode. Also there is the issue of the sub being out of phase in 6-channel direct if it is in phase for other modes? If so, that seems like a problem. If I have to keep changing the phase switch between movies, 5 channel stereo, and 6 channel direct stereo music that may not be worth it. I wonder if the Outlaws could fix this by modifying the ICBM to include a phase control for sub or with a retro-fit of the 950? Ok, here is my understanding from reading this thread:

Two channel analog bypass stereo mode:
Uses only ES-9000 DACs
Double bass
Sub stays in phase with mains for this mode and digital modes
No trim controls

Six channel direct mode:
Uses only ES-9000 DACs
No double bass
Sub out of phase with mains if it is in phase for other modes
Trim controls active

Comments and education welcome!
-HTLearner
Posted by: harp795

Re: 950 2 channel bypass vs 6 channel bypass redux - 04/07/04 11:24 AM

I've searched the forum thoroughly looking for some explaination of the differences between 2 ch bypass and 6 channel bypass. I really haven't found a detail explaination. To my ears, my CD player's analog output connected the 6 channel bypass inputs results in a larger soundstage than if plugged into the 950's CD analog inputs in bypass mode. Also, I find it interesting that you can still control bass and treble in the 6 channel bypass inputs but not in 2 ch bypass. I have always been under the impression that the 2 ch. bypass was the "cleanest" signal path for the Outlaw. Thus, no bass and treble control. Can anyone give a detailed explaination of the signal path of each input? Is there an advantage of having a 80 hz ANALOG crossover vs. the multi position digital crossover(i.e. 40, 60, 80, etc..) in the other inputs?
Posted by: gonk

Re: 950 2 channel bypass vs 6 channel bypass redux - 04/07/04 12:22 PM

Let me see what I can do here...

Two-channel analog bypass (stereo bypass): In this mode, the signal from any stereo analog input is passed directly from input to volume control and through the pre-amp outputs. At the same time, a copy of the analog signal is converted to digital and passed to the 950's bass management module. If the main speakers are set to "small," the bass management module routes this digital signal through the low pass crossover and creates a subwoofer signal, which is then converted back to analog and sent to the sub. If the main speakers are set to large, nothing happens.

Six-channel analog input: This is a separate and purely analog signal path through the 950. The subwoofer output always receives a combination of the LFE input channel and the output of 80Hz low-pass crossovers from the five full range channels. The crossover on/off toggle enables or disables 80Hz high-pass crossovers at the five full range channels. This is all sent to the volume control; I do not recall if the 950's channel delays are applied (I believe they may be), and as you note the bass and treble controls (which I don't think I've ever touched) are applied.

Fixed 80Hz analog crossover versus adjustable digital crossover: Which is better depends at least in part on your speakers. If 80Hz is the preferred crossover point for your combination of speakers and sub, we are talking about the difference between crossover slopes and fundamental design characteristics (which for well designed crossovers should yield comparable performance). If you need a significantly different crossover than 80Hz, then the digital crossover obviously is better.

I'm not sure which signal path might be classified as the "purer" route for stereo analog sources. If you prefer the soundstage when using the six channel analog input, then I would say that's the way to go.

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gonk -- 950 Review | LFM-1 Review | Pre/Pro Comparison Chart | Saloon Links
Posted by: readster

Re: 950 2 channel bypass vs 6 channel bypass redux - 04/07/04 12:57 PM

Is the Sony ES9000 an old model ? I can't imagine a dvd player not having 5.1 ch outputs.
Posted by: gonk

Re: 950 2 channel bypass vs 6 channel bypass redux - 04/07/04 01:18 PM

The ES9000 is an older model, from back when Sony's SACD format was two-channel only. In order to stay competitive with DVD-Audio, they ended up revamping the format somewhat to support multichannel SACD, but the ES9000 remained their flagship SACD player for quite a while.

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gonk -- 950 Review | LFM-1 Review | Pre/Pro Comparison Chart | Saloon Links