TOPIC:

Hey guys, 
   I've done a ton of measuring and tinkering in my room using REW sweeps and Umik-1 mic to determine ideal speaker placement in my decently treated listening room. I am now going to experiment with Dirac and DSP with a minidsp SHD. My question is regarding how to best implement it in the chain. I'd like to continue to use my Hegel h390 DAC and volume control, so would like to implement the SHD as a DSP device only. 

Here's how I intend to set it up: 

Auralic Aries streamer --AES/EBU xlr---> miniDSP SHD ---coax digital RCA---> Hegel h390 ----> speakers 

In this way I would use my Hegel h390's internal DAC and volume control. 

Questions: 
1.) Anyone using their miniDSP SHD in this way (i.e. digital output via coax to integrated DAC/amp?)? 
2.) Do I need to attenuate the volume on the miniDSP to get the proper output voltage via coax so as not to clip when using Hegel volume control? 
3.) Is using the miniDSP as a DAC and connecting to Hegel h390 via analog xlr connection a better way to go? (Can I still use Hegel as volume control then?)

Thanks in advance! 

 

Note there is the SHD Studio model that is all-digital (no DACs) that would be a cheaper option for what you're thinking of.

You may want to apply some attenuation on the SHD Studio to avoid digital clipping, although if this happens will depend on source material and the Dirac Live filters. The maximum attenuation you'd need is 10 dB.

Note that a key strength of the SHDs is subwoofer integration, but this is only an option if they're also used for volume control.

Yes thanks I'm aware of the SHD Studio but figured this way I have the ability to try the miniDSP SHD as a DAC/pre-amp and try the ADC with an analog source to add DSP to my turntable (even though I will probably do neither lol). The price difference wasn't that big so I decided to go for the SHD. Regardless, with either the SHD or the SHD Studio I can connect as specified above and still use my Hegel h390 DAC and volume gain, correct? 
 
I saw on Amir's review on Audio Science Review that at -6.6dB on the SHD he got 4V output via XLR. Via coax would this same attenuation reduce the output to 2V to avoid clipping in the same fashion? How should I go about figuring out the correct amount of attenuation on the SHD to avoid digital clipping?
    My source is Auralic Aries streamer via AES/EBU digital out to AES-EBU digital input on the SHD. 

Thanks again. 

tallbeardedone wrote:

The price difference wasn't that big so I decided to go for the SHD. Regardless, with either the SHD or the SHD Studio I can connect as specified above and still use my Hegel h390 DAC and volume gain, correct? 
 

Have you already purchased an SHD then? The answer to your question above is yes.

The voltage values you referred to from ASR are irrelevant if you're using a digital output, with digital clipping being the issue to watch out for as I mentioned above. I'd suggest you set the SHD master volume to -5 dB and if you don't ever hear a problem, you don't have one. You're only likely to ever have an issue with digital source material. If you want to be more sure of avoiding any issues you can measure the peak gain applied by Dirac Live as discussed in the following thread but this may well be more complicated than you want to get into as someone new to DSP.

www.minidsp.com/forum/dirac-series-suppo...nal-headroom?start=0

Yes the SHD is on the way! Sorry that was a stupid statement regarding ASR measurements. Of course he was using xlr to measure analog voltage. My bad. Thanks very much for the link. I am a physics teacher and love the science behind stereo reproduction and auditory neuroscience so I plan on really digging into the minidsp and getting the most out of the tool. I will learn how to measure the gain added by Dirac and turn the SHD master volume down accordingly to avoid clipping. Thanks. 

I may also try to use the SHD DAC. If I connect xlr analog out to the Hegel can I still use the Hegel for volume control or would I then need to set the Hegel to a set volume and use the SHD as a pre-amp? 

tallbeardedone wrote:

I may also try to use the SHD DAC. If I connect xlr analog out to the Hegel can I still use the Hegel for volume control or would I then need to set the Hegel to a set volume and use the SHD as a pre-amp? 

You could do either.

Shame that there is no direct power amp connection on the H390 because this way, you could avoid a lot of electronics (the complete preamp section) in the analog signal path. The SHD can drive almost any power amp with it's analog output. Anyway I am curious which DAC you will like more, the one in the H390 or the SHD's own.

I love the Hegel. So much power into 4 ohms and the DAC is excellent so I’m happy to feed it digital and let it do the DA conversion and amplify the analog signal, which is what it does extremely well. I will compare to the SHD DAC tho. Still unsure whether to use SHD or Hegel for volume control in that case. 

If you have an unavoidable analog volume control in the signal path (which the H390 have), then there is no reason to use the digital volume control of the SHD, apart from the slight volume reduction to prevent digital clipping caused by EQ boost.
That's why I mentioned the direct power amp connection where the digital volume control of the SHD comes handy.
Anyway, you can try both (or a combination of two) volume controls to get a picture what they do in your system.

Yup correct. But since I really enjoy the analog volume control in the Hegel I'm happy to keep using it for everything. Keen to figure out exactly how much boost Dirac adds so I can turn down the digital master volume on the SHD the minimum amount to give me max headroom in the Hegel while still avoiding digital clipping. Pretty sure the easiest way for me to do that will be adding my laptop running REW as a source, apply Dirac, then running the slow sweep while watching the SHD levels (as linked above by Ultrasonic). 

tallbeardedone wrote:

Yup correct. But since I really enjoy the analog volume control in the Hegel I'm happy to keep using it for everything. Keen to figure out exactly how much boost Dirac adds so I can turn down the digital master volume on the SHD the minimum amount to give me max headroom in the Hegel while still avoiding digital clipping. Pretty sure the easiest way for me to do that will be adding my laptop running REW as a source, apply Dirac, then running the slow sweep while watching the SHD levels (as linked above by Ultrasonic). 

This is not the method I was referring to in my link.There are two better ways to do it if you read on.

This is not the method I was referring to in my link.There are two better ways to do it if you read on.

I read the entire thread. What method would you suggest me use? I was a bit unclear on the other methods. 

tallbeardedone wrote:

This is not the method I was referring to in my link.There are two better ways to do it if you read on.

I read the entire thread. What method would you suggest me use? I was a bit unclear on the other methods. 

You just use REW in loopback configuration with the SHD acting as a 'microphone' as well as the source. I've not got time to check for specific posts right now but can later if you can't find it.

Ultrasonic wrote:

Yeah I was a bit unclear on exactly how to do that but I'm sure I'll figure it out once I have the unit here and get tinkering. The graph where you can see exactly how many dB gain is used at each frequency is super cool. Will figure it out, but may have questions so thanks in advance! 

tallbeardedone wrote:

Ultrasonic wrote:

 

Yeah I was a bit unclear on exactly how to do that but I'm sure I'll figure it out once I have the unit here and get tinkering. The graph where you can see exactly how many dB gain is used at each frequency is super cool. Will figure it out, but may have questions so thanks in advance! 

Possibly there's another thread with the details spelled out. Either way, learn to walk before you can run as you'll need to get your head around the basics of configuring your SHD and running Dirac Live first. Don't expect to just get it and have everything all sorted in an afternoon. You'll be learning and tinkering for a while.