DACs, DIRAC, Preamplification - What am I not understanding?

[newrival]

I have been lurking for some considerable time and now stepping out of the shadows.

I have been running a mDSP SHD into an amplifier to a set of speakers (Revels, JBLs, or NHT), along with two homemade subwoofers, each with Speakerpower amps, for sometime now, and have loved what DIRAC did for my system. (Worth noting is that I have a turntable into a phono preamp going into the SHD.)

Not too long ago, I got a crazy deal on an Okto DAC8 Stereo, and so I picked it up to see what benefits could be had.

Here's where I am at:
The stereo is in a large space at the moment and I would like to keep it here.
When I use the SHD as a "preamp" I cannot get the system to play all that loudly, the SHD does not have adjustable voltage, and I have no additional gain between it and the amp.
When I use the DAC8 to the amp (came with the upgraded voltage output - stated 4.8v), it will play significantly louder - and I do realize there is a -10db reduction in overhead for Dirac.
Here's where I get stuck: I want DIRAC, I want an analog in, I want to be able to play loudly, and I want the performance of the DAC8.
Would it be insane to add a preamp, something like the Audio-GD HE-1 to everything that I've got??

I'm guessing that would look something like Streamer >>> DAC8 >>> SHD >>> Preamp & subs >>> Amplifier >>> speakers
with the turntable >>> phono >>> preamp.

This seems completely nuts to me, but in going through all the threads I can find here, I dont see any reasonable solutions to do it all. Most people seem to be all digital, but I am not.
Is there a device that I could swap? I looked at the DIRAC on computer sollution, but that only seems to work if it is also your source. Is there not a DIRAC unit that would work in between the preamplification and amplification sections? Is this not how it works on things like the NAD M33 or the Anthem STR? why no external device?

Sorry if i'm just being dense, but I'm just not seeing the path forward

Thanks for any assistance!

 

[NTK]

Welcome to ASR.

Placing the Okto DAC upstream of the miniDSP SHD would be a waste. The SHD will reconvert the analog output signal of the Okto DAC with its onboard ADC back into digital for processing, then output the DSP'd signal using its onboard DAC.

Why not put the Okto DAC downstream of the SHD, and feed the Okto DAC with the digital output from the SHD?

Streamer >>> SHD digital out >>> DAC8 >>> Preamp (if necessary) >>> Amplifier >>> Speakers
                                                     └─ analog out >>> subs

If the DAC8 output is insufficient and you need to amplify it, I think the Topping Pre90 is a much better choice than the Audio-GD.

 

[Kervel]

When I use the SHD as a "preamp" I cannot get the system to play all that loudly, the SHD does not have adjustable voltage, and I have no additional gain between it and the amp.

The SHD puts out 4 volts on XLR, which should drive any Poweramp to max level. If you find your volume to low, my first guess as an issue with the Dirac filters. A simple check is to turn off Dirac on the minidsp and pick a present without any filter active. Do you still have the low volume issue?

 

[levimax]

Welcome to ASR. For what you want to do a computer with an ADC for your TT seems like a great solution. You can stream, store, convert, rip, use remote control and run DIRAC from the computer. I connect my TT to a balanced DIY buffer then to an ADC and do digital RIAA, works great. If you want plug and play a Parks Puffin or a phono pre to an ADC will also work. My DSP eats up 8 dB of headroom which is a lot so I know where you are coming from. You need to be aware of your filters and gain along the chain but a computer will make that easier to manage as well. Good luck.

 

[newrival]

Welcome to ASR.

Placing the Okto DAC upstream of the miniDSP SHD would be a waste. The SHD will reconvert the analog output signal of the Okto DAC with its onboard ADC back into digital for processing, then output the DSP'd signal using its onboard DAC.

Why not put the Okto DAC downstream of the SHD, and feed the Okto DAC with the digital output from the SHD?

Streamer >>> SHD digital out >>> DAC8 >>> Preamp (if necessary) >>> Amplifier >>> Speakers
                                                     └─ analog out >>> subs

If the DAC8 output is insufficient and you need to amplify it, I think the Topping Pre90 is a much better choice than the Audio-GD.

Aren't I losing some of the benefit of DIRAC by having the SHD at the front of the chain? Am I misunderstanding how it works in the chain?

 

[newrival]

The SHD puts out 4 volts on XLR, which should drive any Poweramp to max level. If you find your volume to low, my first guess as an issue with the Dirac filters. A simple check is to turn off Dirac on the minidsp and pick a present without any filter active. Do you still have the low volume issue?

From what I understand from the manual, Dirac required 10db of overhead to boost up ton 10db of signal within the bandwidth. -10db of signal is quite a chunk out of the 4v, no?
I am going to try what you suggested tonight

 

[newrival]

Welcome to ASR. For what you want to do a computer with an ADC for your TT seems like a great solution. You can stream, store, convert, rip, use remote control and run DIRAC from the computer. I connect my TT to a balanced DIY buffer then to an ADC and do digital RIAA, works great. If you want plug and play a Parks Puffin or a phono pre to an ADC will also work. My DSP eats up 8 dB of headroom which is a lot so I know where you are coming from. You need to be aware of your filters and gain along the chain but a computer will make that easier to manage as well. Good luck.

This sounds interesting. So where is the PC in the chain of your componentry?

 

[Kervel]

From what I understand from the manual, Dirac required 10db of overhead to boost up ton 10db of signal within the bandwidth. -10db of signal is quite a chunk out of the 4v, no?
I am going to try what you suggested tonight

Yea, so if you confirm this is the issue, then you can i) check the level of your powered subs and perhaps raise the gain a little (so Dirac has more flexibility to cut away later), and ii) run Dirac again but use the settings to prevent boosting too much (essententially changing the level of the target curve).

 

[newrival]

Welcome to ASR.

Placing the Okto DAC upstream of the miniDSP SHD would be a waste. The SHD will reconvert the analog output signal of the Okto DAC with its onboard ADC back into digital for processing, then output the DSP'd signal using its onboard DAC.

Why not put the Okto DAC downstream of the SHD, and feed the Okto DAC with the digital output from the SHD?

‍ I think I'm finally getting it through my dense head. Tell me if I'm wrong:

It doesn't much matter if the room correction is upstream because it's sampling downstream and correcting the sum of the system (signal exiting the speakers and hitting the microphone). And because you'd be passing the signal on the digital domain, as is the case in how you suggested laying it out, you aren't losing anything.

Am I more or less understanding this correctly?

 

[NTK]

Aren't I losing some of the benefit of DIRAC by having the SHD at the front of the chain? Am I misunderstanding how it works in the chain?

No, you won't lose the benefits of Dirac. Dirac on the SHD shapes the frequency response curves and perform cross-over for the main speakers and subs. The SHD will then send the two (or three, if you use separate EQ for your subs) sets of signals to the corresponding output connectors. The Okto DAC simply performs the function of converting the Dirac processed digital signals into analog, and the pre/power amps provide the gain to power the main speakers.

To the SHD and Dirac, the Okto and amps are no different than any other speaker amps. (The SHD outputs, for each channel, the same signals to the coax digital out, balanced XLR out, and unbalanced RCA out.)

Dirac actually sells a software suite (link) that runs on PC/Mac, which places the Dirac room EQ processing at the very front end of the chain.

 

[Kal Rubinson]

Dirac actually sells a software suite (link) that runs on PC/Mac, which places the Dirac room EQ processing at the very front end of the chain.

And it has other advantages over the embedded version.

 

[newrival]

Also, does the digital out automatically bypass decodingthe codecs, or will I have to address that in the settings so the dac8 can do the processing.

Though, if the SHD is not decoding, how could it be applying the DSP correction to the signal if it is yet to be decoded?

 

[antcollinet]

Also, does the digital out automatically bypass decodingthe codecs, or will I have to address that in the settings so the dac8 can do the processing.

Though, if the SHD is not decoding, how could it be applying the DSP correction to the signal if it is yet to be decoded?

Any decoding needed has to be done by the SHD. But it doesn't matter which device does the decoding. You just want the DAC8 to do the conversion to analogue so you get the higher output voltage.

 

[newrival]

No, you won't lose the benefits of Dirac. Dirac on the SHD shapes the frequency response curves and perform cross-over for the main speakers and subs. The SHD will then send the two (or three, if you use separate EQ for your subs) sets of signals to the corresponding output connectors. The Okto DAC simply performs the function of converting the Dirac processed digital signals into analog, and the pre/power amps provide the gain to power the main speakers.

To the SHD and Dirac, the Okto and amps are no different than any other speaker amps. (The SHD outputs, for each channel, the same signals to the coax digital out, balanced XLR out, and unbalanced RCA out.)

Dirac actually sells a software suite (link) that runs on PC/Mac, which places the Dirac room EQ processing at the very front end of the chain.

Thanks NTK I need to think in this to let it sink in. I appreciate you thalong the time to explain it.

 

[levimax]

This sounds interesting. So where is the PC in the chain of your componentry?

I use a PC with Foobar 2000 to DAC via USB to amps. ADC for TT connected to PC and plays through Foobar 2000 which also supports FIR DSP filters. In your case you would use Foobar's VST plugin support to send its output to DIRAC which then would output to your DAC. I believe you can do the same with J River or Roon or any software player that supports VST plug ins.

 

[mdsimon2]

What specific amplifiers are you using? The SHD does not automatically apply 10 dB attenuation, did you apply this yourself?

Michael

 

[newrival]

I use a PC with Foobar 2000 to DAC via USB to amps. ADC for TT connected to PC and plays through Foobar 2000 which also supports FIR DSP filters. In your case you would use Foobar's VST plugin support to send its output to DIRAC which then would output to your DAC. I believe you can do the same with J River or Roon or any software player that supports VST plug ins.

Thank you, this actually makes sense to me - at least conceptually. haha

 

[newrival]

What specific amplifiers are you using? The SHD does not automatically apply 10 dB attenuation, did you apply this yourself?

Michael

I had a few that I use, power physics, Class D Audio, and D-Sonic. The SHD manual states not to go above -10db of attenuation, so i dont.

 

[newrival]

Any decoding needed has to be done by the SHD. But it doesn't matter which device does the decoding. You just want the DAC8 to do the conversion to analogue so you get the higher output voltage.

wouldnt that be a huge waste just to get a little gain? I thought I waould want the DAC8 to be doing the conversion, as it is a better DAC than the SHD

 

[TimW]

What are your routing matrix and output gain settings?

What about the Dirac settings on the input tab?

Where are you not going over -10? The volume control?