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AV Pre-Pro and bi-amping

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Thread Starter #21
There are a lot of issues raised in your post.

1) there is no point in passive biamping
2) if you are going to use active crossovers it’s better to do this digitally
3) if using digital crossovers you don’t want a DAC8 stereo, you want a DAC8 pro
4) for analog crossovers Ashly makes a decent one but i know of no analog crossover that won’t be the SINAD bottleneck if you are using an Okto DAC8 and PuriFI amps

Why not figure out where the crossovers are going to be before we figure out the HT bypass mode?
1) Yes that would a temporary situation.
2) Agreed
3) Yes makes sense
4) OK I don't know anything about performances of analogue Xover.

Could we do Xover with a mini dsp studio shd?
It could be placed before dac8 and could take digital output from prepro?
 

waynel

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#22
1) Yes that would a temporary situation.
2) Agreed
3) Yes makes sense
4) OK I don't know anything about performances of analogue Xover.

Could we do Xover with a mini dsp studio shd?
It could be placed before dac8 and could take digital output from prepro?
Yes , that’s a good solution and will add room correction for music mode as well. (You will need to bypass the crossovers in your speakers). If doing this you can use any AV pre/pro and send the LR pre outs to an ADC then send to miniDSP. No switches or splitters needed.

If you are going to use subs as well for music then you will need more channels and a NanoDigi would work well with the Okto DAC8 pro.
 
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Thread Starter #23
Yes , that’s a good solution and will add room correction for music mode as well. (You will need to bypass the crossovers in your speakers). If doing this you can use any AV pre/pro and send the LR pre outs to an ADC then send to miniDSP. No switches or splitters needed.

If you are going to use subs as well for music then you will need more channels and a NanoDigi would work well with the Okto DAC8 pro.
So basically you're saying that signal from prepro to studio shd will follow the path: DAC from prepro --> external ADC --> studio shd.

Is there anyway to avoid the double conversion and direct digital signal from pre-pro to studio shd?

Don't understand your second part. For sub I could use second AES/EBU output from shd studio with a cheaper DAC?
 

waynel

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#24
So basically you're saying that signal from prepro to studio shd will follow the path: DAC from prepro --> external ADC --> studio shd.

Is there anyway to avoid the double conversion and direct digital signal from pre-pro to studio shd?

Don't understand your second part. For sub I could use second AES/EBU output from shd studio with a cheaper DAC?
No, a bi-amped 2 channel system requires all 4 channels of the SHD studio, L high, L low, R high, R low. No channels left for subs. A nanodigi handles 8 channels , same for Okto DAC 8 pro.
 
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Thread Starter #25
Yes , that’s a good solution and will add room correction for music mode as well. (You will need to bypass the crossovers in your speakers). If doing this you can use any AV pre/pro and send the LR pre outs to an ADC then send to miniDSP. No switches or splitters needed.

If you are going to use subs as well for music then you will need more channels and a NanoDigi would work well with the Okto DAC8 pro.
Sorry, what would you use the NanoDigi for?
 

waynel

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#26
Sorry, what would you use the NanoDigi for?
To do the crossover digitally as well as room correction. This is instead of a SHD studio.
 
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Thread Starter #27
No, a bi-amped 2 channel system requires all 4 channels of the SHD studio, L high, L low, R high, R low. No channels left for subs. A nanodigi handles 8 channels , same for Okto DAC 8 pro.
OK understood! :)
 
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Thread Starter #28
To do the crossover digitally as well as room correction. This is instead of a SHD studio.
Thanks a lot Waynel! Understood :)

One thing not clear. Is there anyway to avoid double conversiin digital to analogue by prepro and then analogue to digital by external ADC? What ADC would you suggest?
 

Tom C

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#29
A person runs into this problem in other use scenarios as well. The difficulty boils down to content protection. Cable boxes, satellite boxes, TV’s and Blu-ray disc players don’t usually have multi-channel digital out, other than HDMI, due to HDMI licensing agreements (and most DSP units and digital sound cards for PC don’t have HDMI in). Most often you find analog out, and in some cases digital stereo out. Having said that, my DirecTV satellite box has toslink optical 5.1 Dolby out. So, it’s really important to plan things out according to your exact use case. If you go with bi-amp stereo (and from the sounds of it, that’s what you’d like to do), things are sometimes a bit easier...

You mentioned streamer, and you mentioned AVR, which to me implies home theater. Do you have a streaming music service now, or do you have a particular one in mind? Do you want audio for watching TV to go through this system? The answers to these questions will affect your system choices, because of content restrictions.

For the crossover, you have to choose if you want digital or analog. Analog is possible and exists, but is harder to find, may be more expensive, and may not do as good a job performance wise as a digital crossover. For these reasons, I expect most people wanting to do something like this find a digital crossover to be preferable.

If you decide on a digital crossover, whatever device you want to use will have either a digital input, or a built-in ADC. And there’s the rub. One way or the other, you have to have a suitable digital interface between the source and the DSP, and the options are restricted. An AVR is purpose built for multichannel home theater, so while you might be able to adapt it for your application, there may be alternatives that would be somewhat simpler and save you time, money and space.

A lot of DSP devices are designed specifically for room correction, so they take the range of audio frequencies and divide them into 10, 12, 15 bands or more. What you want to do is much simpler. You want a separate band for each driver in the cabinet, so maybe two or three, likely four at most, for each cabinet. One solution you might consider is something like a Crown 1502. It is a stereo power amp with a built-in digital ADC and crossover, so analog in and analog out, which simplifies connecting it into the system. It would be relatively easy to use for what your looking to do, and would work with anything, at least anything I can think of. That’s especially important if you ever want to reconfigure the system to use different sources, a different preamp, or different speakers. Harman has little charts available online to help explain how their systems work and how to put them together.
 
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#30
Hello

This is how I do it. My mains have a pair of dedicated stereo amps and an active crossover. The L/R output of my HT prepro drives the active crossover. It's a very simple set-up no difference than if I was using a stereo preamp. This all done analog after the prepro. I can do all the EQ I want digitally in the Prepro. My sources are all digital.

Rob :)
 

Tom C

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#32
That dbx looks sweet! Depends on how you run it though. THD+ noise is spec’ed at .004% @ +4dBu and degrades to .04% @ +20dBu. Is that within your tolerance for noise and distortion? Eigentakt level of performance would probably be lost/wasted if this is in the chain.
 
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#33
That dbx looks sweet! Depends on how you run it though. THD+ noise is spec’ed at .004% @ +4dBu and degrades to .04% @ +20dBu. Is that within your tolerance for noise and distortion? Eigentakt level of performance would probably be lost/wasted if this is in the chain.
Perhaps if one looks at it from the perspective of speaker distortion?
 

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